1

LATERAL EARTH PRESSUREGuest Lecture

Sal Collage of Engineering amp ResearchAhmedabad

Date 14th February2012

Prof SPPARMARDEPARTMENT OF CIVIL ENGINEERINGDHARMASINH DESAI UNIVERSITY NADIADMail samirddugmailcom

2

WHERE EARTH PRESSURE

Calculating lateral earth pressure is necessary in order to design structures such as

Retaining Walls Bridge Abutments Bulkheads Temporary Earth Support Systems Basement Walls

3

TYPES OF RETAINING WALLS

4

USE OF RETAINING WALLS

5

USE OF RETAINING WALLS

6

IN GEOTECHNICAL ENGINEERING IT IS OFTEN NECESSARY TO PREVENT LATERAL SOIL MOVEMENTS

Cantileverretaining wall

Braced excavation

Anchored sheet pile

7

DEFINITION OF KEY TERMS Active earth pressure coefficient (Ka) It is

the ratio of horizontal and vertical principal effective stresses when a retaining wall moves away (by a small amount) from the retained soil Passive earth pressure coefficient (Kp) It is the ratio of horizontal and vertical principal effective stresses when a retaining wall is forced against a soil mass Coefficient of earth pressure at rest (Ko) It is the ratio of horizontal and vertical principal effective stresses when the retaining wall does not move at all ie it is ldquoat restrdquo

8

LATERAL EARTH PRESSURE ndash BASIC CONCEPTS

We will consider the lateral pressure on a vertical wall that retains soil on one side

First we will consider a drained case ie The shear strength of the soil is governed by its angle of friction φ

In addition we will make the following assumptions

ndash The interface between the wall and the soil is frictionless

ndash The soil surface is horizontal and there are no shear stresses on horizontal and vertical planes ie The horizontal and vertical stresses are principal stresses

ndash The wall is rigid and extends to an infinite depth in a dry homogenous isotropic soil mass

ndash The soil is loose and initially in an at-rest state

9

LATERAL EARTH PRESSURE THEORY

There are two classical earth pressure theories They are

1 Coulombs earth pressure theory 2 Rankines earth pressure theory

10

THE RANKINE THEORY ASSUMES

There is no adhesion or friction between the wall and soil

Lateral pressure is limited to vertical walls Failure (in the backfill) occurs as a sliding

wedge along an assumed failure plane defined by φ

Lateral pressure varies linearly with depth and the resultant pressure is located one-third of the height (H) above the base of the wall

The resultant force is parallel to the backfill surface

11

THE COULOMB THEORY IS SIMILAR TO RANKINE EXCEPT THAT There is friction between the wall and soil

and takes this into account by using a soil-wall friction angle of δ

Note that δ ranges from φ2 to 2φ3 and δ = 2φ3 is commonly used

Lateral pressure is not limited to vertical walls

The resultant force is not necessarily parallel to the backfill surface because of the soil-wall friction value δ

12

LATERAL EARTH PRESSURE FOR AT REST CONDITION If the wall is rigid and does not move with the

pressure exerted on the wall the soil behind the wall will be in a state of elastic equilibrium

13

LATERAL EARTH PRESSURE FOR AT REST CONDITION

Element E is subjected to the following pressures

E

14

LATERAL EARTH PRESSURE FOR AT REST CONDITION If we consider the backfill is homogeneous

then v and h both increase linearly with depth z

In such a case the ratio of h to v remains constant with respect to depth that is

Where Ko is called the coefficient of earth pressure for the at rest condition or at rest earth pressure Coefficient

The lateral earth pressure h acting on the wall at any depth z may be expressed as

15

LATERAL EARTH PRESSURE FOR AT REST CONDITION

16

COEFFICIENTS OF EARTH PRESSURE FOR AT REST CONDITION KO

Type of soil Ip Ko

Loose sand saturated 046Dense sand saturated 036Dense sand dry (e = 06)

049

Loose sand dry (e = 08)

064

Compacted clay 9 042Compacted clay 31 060Organic silty clay undisturbed (w = 74)

45 057

17

FACTORS AFFECTING KO

The value of Ko depends upon the relative density of the sand and the process by which the deposit was formed

If this process does not involve artificial tamping the value of Ko ranges from about 040 for loose sand to 06 for dense sand

Tamping the layers may increase it to 08

18

DEVELOPMENT OF ACTIVE AND PASSIVE EARTH PRESSURES

19

HORIZONTAL STRESS AS A FUNCTION OF THE DISPLACEMENT

20

DEVELOPMENT OF EARTH PRESSURES

Active Pressures Overburden (σ1)Driving

Passive Pressures Wall (σ3) Driving

21

ACTIVE EARTH PRESSURE

‐ Wall moves away from soil

22

ACTIVE EARTH PRESSURE

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

2

WHERE EARTH PRESSURE

Calculating lateral earth pressure is necessary in order to design structures such as

Retaining Walls Bridge Abutments Bulkheads Temporary Earth Support Systems Basement Walls

3

TYPES OF RETAINING WALLS

4

USE OF RETAINING WALLS

5

USE OF RETAINING WALLS

6

IN GEOTECHNICAL ENGINEERING IT IS OFTEN NECESSARY TO PREVENT LATERAL SOIL MOVEMENTS

Cantileverretaining wall

Braced excavation

Anchored sheet pile

7

DEFINITION OF KEY TERMS Active earth pressure coefficient (Ka) It is

the ratio of horizontal and vertical principal effective stresses when a retaining wall moves away (by a small amount) from the retained soil Passive earth pressure coefficient (Kp) It is the ratio of horizontal and vertical principal effective stresses when a retaining wall is forced against a soil mass Coefficient of earth pressure at rest (Ko) It is the ratio of horizontal and vertical principal effective stresses when the retaining wall does not move at all ie it is ldquoat restrdquo

8

LATERAL EARTH PRESSURE ndash BASIC CONCEPTS

We will consider the lateral pressure on a vertical wall that retains soil on one side

First we will consider a drained case ie The shear strength of the soil is governed by its angle of friction φ

In addition we will make the following assumptions

ndash The interface between the wall and the soil is frictionless

ndash The soil surface is horizontal and there are no shear stresses on horizontal and vertical planes ie The horizontal and vertical stresses are principal stresses

ndash The wall is rigid and extends to an infinite depth in a dry homogenous isotropic soil mass

ndash The soil is loose and initially in an at-rest state

9

LATERAL EARTH PRESSURE THEORY

There are two classical earth pressure theories They are

1 Coulombs earth pressure theory 2 Rankines earth pressure theory

10

THE RANKINE THEORY ASSUMES

There is no adhesion or friction between the wall and soil

Lateral pressure is limited to vertical walls Failure (in the backfill) occurs as a sliding

wedge along an assumed failure plane defined by φ

Lateral pressure varies linearly with depth and the resultant pressure is located one-third of the height (H) above the base of the wall

The resultant force is parallel to the backfill surface

11

THE COULOMB THEORY IS SIMILAR TO RANKINE EXCEPT THAT There is friction between the wall and soil

and takes this into account by using a soil-wall friction angle of δ

Note that δ ranges from φ2 to 2φ3 and δ = 2φ3 is commonly used

Lateral pressure is not limited to vertical walls

The resultant force is not necessarily parallel to the backfill surface because of the soil-wall friction value δ

12

LATERAL EARTH PRESSURE FOR AT REST CONDITION If the wall is rigid and does not move with the

pressure exerted on the wall the soil behind the wall will be in a state of elastic equilibrium

13

LATERAL EARTH PRESSURE FOR AT REST CONDITION

Element E is subjected to the following pressures

E

14

LATERAL EARTH PRESSURE FOR AT REST CONDITION If we consider the backfill is homogeneous

then v and h both increase linearly with depth z

In such a case the ratio of h to v remains constant with respect to depth that is

Where Ko is called the coefficient of earth pressure for the at rest condition or at rest earth pressure Coefficient

The lateral earth pressure h acting on the wall at any depth z may be expressed as

15

LATERAL EARTH PRESSURE FOR AT REST CONDITION

16

COEFFICIENTS OF EARTH PRESSURE FOR AT REST CONDITION KO

Type of soil Ip Ko

Loose sand saturated 046Dense sand saturated 036Dense sand dry (e = 06)

049

Loose sand dry (e = 08)

064

Compacted clay 9 042Compacted clay 31 060Organic silty clay undisturbed (w = 74)

45 057

17

FACTORS AFFECTING KO

The value of Ko depends upon the relative density of the sand and the process by which the deposit was formed

If this process does not involve artificial tamping the value of Ko ranges from about 040 for loose sand to 06 for dense sand

Tamping the layers may increase it to 08

18

DEVELOPMENT OF ACTIVE AND PASSIVE EARTH PRESSURES

19

HORIZONTAL STRESS AS A FUNCTION OF THE DISPLACEMENT

20

DEVELOPMENT OF EARTH PRESSURES

Active Pressures Overburden (σ1)Driving

Passive Pressures Wall (σ3) Driving

21

ACTIVE EARTH PRESSURE

‐ Wall moves away from soil

22

ACTIVE EARTH PRESSURE

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

3

TYPES OF RETAINING WALLS

4

USE OF RETAINING WALLS

5

USE OF RETAINING WALLS

6

IN GEOTECHNICAL ENGINEERING IT IS OFTEN NECESSARY TO PREVENT LATERAL SOIL MOVEMENTS

Cantileverretaining wall

Braced excavation

Anchored sheet pile

7

DEFINITION OF KEY TERMS Active earth pressure coefficient (Ka) It is

the ratio of horizontal and vertical principal effective stresses when a retaining wall moves away (by a small amount) from the retained soil Passive earth pressure coefficient (Kp) It is the ratio of horizontal and vertical principal effective stresses when a retaining wall is forced against a soil mass Coefficient of earth pressure at rest (Ko) It is the ratio of horizontal and vertical principal effective stresses when the retaining wall does not move at all ie it is ldquoat restrdquo

8

LATERAL EARTH PRESSURE ndash BASIC CONCEPTS

We will consider the lateral pressure on a vertical wall that retains soil on one side

First we will consider a drained case ie The shear strength of the soil is governed by its angle of friction φ

In addition we will make the following assumptions

ndash The interface between the wall and the soil is frictionless

ndash The soil surface is horizontal and there are no shear stresses on horizontal and vertical planes ie The horizontal and vertical stresses are principal stresses

ndash The wall is rigid and extends to an infinite depth in a dry homogenous isotropic soil mass

ndash The soil is loose and initially in an at-rest state

9

LATERAL EARTH PRESSURE THEORY

There are two classical earth pressure theories They are

1 Coulombs earth pressure theory 2 Rankines earth pressure theory

10

THE RANKINE THEORY ASSUMES

There is no adhesion or friction between the wall and soil

Lateral pressure is limited to vertical walls Failure (in the backfill) occurs as a sliding

wedge along an assumed failure plane defined by φ

Lateral pressure varies linearly with depth and the resultant pressure is located one-third of the height (H) above the base of the wall

The resultant force is parallel to the backfill surface

11

THE COULOMB THEORY IS SIMILAR TO RANKINE EXCEPT THAT There is friction between the wall and soil

and takes this into account by using a soil-wall friction angle of δ

Note that δ ranges from φ2 to 2φ3 and δ = 2φ3 is commonly used

Lateral pressure is not limited to vertical walls

The resultant force is not necessarily parallel to the backfill surface because of the soil-wall friction value δ

12

LATERAL EARTH PRESSURE FOR AT REST CONDITION If the wall is rigid and does not move with the

pressure exerted on the wall the soil behind the wall will be in a state of elastic equilibrium

13

LATERAL EARTH PRESSURE FOR AT REST CONDITION

Element E is subjected to the following pressures

E

14

LATERAL EARTH PRESSURE FOR AT REST CONDITION If we consider the backfill is homogeneous

then v and h both increase linearly with depth z

In such a case the ratio of h to v remains constant with respect to depth that is

Where Ko is called the coefficient of earth pressure for the at rest condition or at rest earth pressure Coefficient

The lateral earth pressure h acting on the wall at any depth z may be expressed as

15

LATERAL EARTH PRESSURE FOR AT REST CONDITION

16

COEFFICIENTS OF EARTH PRESSURE FOR AT REST CONDITION KO

Type of soil Ip Ko

Loose sand saturated 046Dense sand saturated 036Dense sand dry (e = 06)

049

Loose sand dry (e = 08)

064

Compacted clay 9 042Compacted clay 31 060Organic silty clay undisturbed (w = 74)

45 057

17

FACTORS AFFECTING KO

The value of Ko depends upon the relative density of the sand and the process by which the deposit was formed

If this process does not involve artificial tamping the value of Ko ranges from about 040 for loose sand to 06 for dense sand

Tamping the layers may increase it to 08

18

DEVELOPMENT OF ACTIVE AND PASSIVE EARTH PRESSURES

19

HORIZONTAL STRESS AS A FUNCTION OF THE DISPLACEMENT

20

DEVELOPMENT OF EARTH PRESSURES

Active Pressures Overburden (σ1)Driving

Passive Pressures Wall (σ3) Driving

21

ACTIVE EARTH PRESSURE

‐ Wall moves away from soil

22

ACTIVE EARTH PRESSURE

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

4

USE OF RETAINING WALLS

5

USE OF RETAINING WALLS

6

IN GEOTECHNICAL ENGINEERING IT IS OFTEN NECESSARY TO PREVENT LATERAL SOIL MOVEMENTS

Cantileverretaining wall

Braced excavation

Anchored sheet pile

7

DEFINITION OF KEY TERMS Active earth pressure coefficient (Ka) It is

the ratio of horizontal and vertical principal effective stresses when a retaining wall moves away (by a small amount) from the retained soil Passive earth pressure coefficient (Kp) It is the ratio of horizontal and vertical principal effective stresses when a retaining wall is forced against a soil mass Coefficient of earth pressure at rest (Ko) It is the ratio of horizontal and vertical principal effective stresses when the retaining wall does not move at all ie it is ldquoat restrdquo

8

LATERAL EARTH PRESSURE ndash BASIC CONCEPTS

We will consider the lateral pressure on a vertical wall that retains soil on one side

First we will consider a drained case ie The shear strength of the soil is governed by its angle of friction φ

In addition we will make the following assumptions

ndash The interface between the wall and the soil is frictionless

ndash The soil surface is horizontal and there are no shear stresses on horizontal and vertical planes ie The horizontal and vertical stresses are principal stresses

ndash The wall is rigid and extends to an infinite depth in a dry homogenous isotropic soil mass

ndash The soil is loose and initially in an at-rest state

9

LATERAL EARTH PRESSURE THEORY

There are two classical earth pressure theories They are

1 Coulombs earth pressure theory 2 Rankines earth pressure theory

10

THE RANKINE THEORY ASSUMES

There is no adhesion or friction between the wall and soil

Lateral pressure is limited to vertical walls Failure (in the backfill) occurs as a sliding

wedge along an assumed failure plane defined by φ

Lateral pressure varies linearly with depth and the resultant pressure is located one-third of the height (H) above the base of the wall

The resultant force is parallel to the backfill surface

11

THE COULOMB THEORY IS SIMILAR TO RANKINE EXCEPT THAT There is friction between the wall and soil

and takes this into account by using a soil-wall friction angle of δ

Note that δ ranges from φ2 to 2φ3 and δ = 2φ3 is commonly used

Lateral pressure is not limited to vertical walls

The resultant force is not necessarily parallel to the backfill surface because of the soil-wall friction value δ

12

LATERAL EARTH PRESSURE FOR AT REST CONDITION If the wall is rigid and does not move with the

pressure exerted on the wall the soil behind the wall will be in a state of elastic equilibrium

13

LATERAL EARTH PRESSURE FOR AT REST CONDITION

Element E is subjected to the following pressures

E

14

LATERAL EARTH PRESSURE FOR AT REST CONDITION If we consider the backfill is homogeneous

then v and h both increase linearly with depth z

In such a case the ratio of h to v remains constant with respect to depth that is

Where Ko is called the coefficient of earth pressure for the at rest condition or at rest earth pressure Coefficient

The lateral earth pressure h acting on the wall at any depth z may be expressed as

15

LATERAL EARTH PRESSURE FOR AT REST CONDITION

16

COEFFICIENTS OF EARTH PRESSURE FOR AT REST CONDITION KO

Type of soil Ip Ko

Loose sand saturated 046Dense sand saturated 036Dense sand dry (e = 06)

049

Loose sand dry (e = 08)

064

Compacted clay 9 042Compacted clay 31 060Organic silty clay undisturbed (w = 74)

45 057

17

FACTORS AFFECTING KO

The value of Ko depends upon the relative density of the sand and the process by which the deposit was formed

If this process does not involve artificial tamping the value of Ko ranges from about 040 for loose sand to 06 for dense sand

Tamping the layers may increase it to 08

18

DEVELOPMENT OF ACTIVE AND PASSIVE EARTH PRESSURES

19

HORIZONTAL STRESS AS A FUNCTION OF THE DISPLACEMENT

20

DEVELOPMENT OF EARTH PRESSURES

Active Pressures Overburden (σ1)Driving

Passive Pressures Wall (σ3) Driving

21

ACTIVE EARTH PRESSURE

‐ Wall moves away from soil

22

ACTIVE EARTH PRESSURE

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

5

USE OF RETAINING WALLS

6

IN GEOTECHNICAL ENGINEERING IT IS OFTEN NECESSARY TO PREVENT LATERAL SOIL MOVEMENTS

Cantileverretaining wall

Braced excavation

Anchored sheet pile

7

DEFINITION OF KEY TERMS Active earth pressure coefficient (Ka) It is

the ratio of horizontal and vertical principal effective stresses when a retaining wall moves away (by a small amount) from the retained soil Passive earth pressure coefficient (Kp) It is the ratio of horizontal and vertical principal effective stresses when a retaining wall is forced against a soil mass Coefficient of earth pressure at rest (Ko) It is the ratio of horizontal and vertical principal effective stresses when the retaining wall does not move at all ie it is ldquoat restrdquo

8

LATERAL EARTH PRESSURE ndash BASIC CONCEPTS

We will consider the lateral pressure on a vertical wall that retains soil on one side

First we will consider a drained case ie The shear strength of the soil is governed by its angle of friction φ

In addition we will make the following assumptions

ndash The interface between the wall and the soil is frictionless

ndash The soil surface is horizontal and there are no shear stresses on horizontal and vertical planes ie The horizontal and vertical stresses are principal stresses

ndash The wall is rigid and extends to an infinite depth in a dry homogenous isotropic soil mass

ndash The soil is loose and initially in an at-rest state

9

LATERAL EARTH PRESSURE THEORY

There are two classical earth pressure theories They are

1 Coulombs earth pressure theory 2 Rankines earth pressure theory

10

THE RANKINE THEORY ASSUMES

There is no adhesion or friction between the wall and soil

Lateral pressure is limited to vertical walls Failure (in the backfill) occurs as a sliding

wedge along an assumed failure plane defined by φ

Lateral pressure varies linearly with depth and the resultant pressure is located one-third of the height (H) above the base of the wall

The resultant force is parallel to the backfill surface

11

THE COULOMB THEORY IS SIMILAR TO RANKINE EXCEPT THAT There is friction between the wall and soil

and takes this into account by using a soil-wall friction angle of δ

Note that δ ranges from φ2 to 2φ3 and δ = 2φ3 is commonly used

Lateral pressure is not limited to vertical walls

The resultant force is not necessarily parallel to the backfill surface because of the soil-wall friction value δ

12

LATERAL EARTH PRESSURE FOR AT REST CONDITION If the wall is rigid and does not move with the

pressure exerted on the wall the soil behind the wall will be in a state of elastic equilibrium

13

LATERAL EARTH PRESSURE FOR AT REST CONDITION

Element E is subjected to the following pressures

E

14

LATERAL EARTH PRESSURE FOR AT REST CONDITION If we consider the backfill is homogeneous

then v and h both increase linearly with depth z

In such a case the ratio of h to v remains constant with respect to depth that is

Where Ko is called the coefficient of earth pressure for the at rest condition or at rest earth pressure Coefficient

The lateral earth pressure h acting on the wall at any depth z may be expressed as

15

LATERAL EARTH PRESSURE FOR AT REST CONDITION

16

COEFFICIENTS OF EARTH PRESSURE FOR AT REST CONDITION KO

Type of soil Ip Ko

Loose sand saturated 046Dense sand saturated 036Dense sand dry (e = 06)

049

Loose sand dry (e = 08)

064

Compacted clay 9 042Compacted clay 31 060Organic silty clay undisturbed (w = 74)

45 057

17

FACTORS AFFECTING KO

The value of Ko depends upon the relative density of the sand and the process by which the deposit was formed

If this process does not involve artificial tamping the value of Ko ranges from about 040 for loose sand to 06 for dense sand

Tamping the layers may increase it to 08

18

DEVELOPMENT OF ACTIVE AND PASSIVE EARTH PRESSURES

19

HORIZONTAL STRESS AS A FUNCTION OF THE DISPLACEMENT

20

DEVELOPMENT OF EARTH PRESSURES

Active Pressures Overburden (σ1)Driving

Passive Pressures Wall (σ3) Driving

21

ACTIVE EARTH PRESSURE

‐ Wall moves away from soil

22

ACTIVE EARTH PRESSURE

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

6

IN GEOTECHNICAL ENGINEERING IT IS OFTEN NECESSARY TO PREVENT LATERAL SOIL MOVEMENTS

Cantileverretaining wall

Braced excavation

Anchored sheet pile

7

DEFINITION OF KEY TERMS Active earth pressure coefficient (Ka) It is

the ratio of horizontal and vertical principal effective stresses when a retaining wall moves away (by a small amount) from the retained soil Passive earth pressure coefficient (Kp) It is the ratio of horizontal and vertical principal effective stresses when a retaining wall is forced against a soil mass Coefficient of earth pressure at rest (Ko) It is the ratio of horizontal and vertical principal effective stresses when the retaining wall does not move at all ie it is ldquoat restrdquo

8

LATERAL EARTH PRESSURE ndash BASIC CONCEPTS

We will consider the lateral pressure on a vertical wall that retains soil on one side

First we will consider a drained case ie The shear strength of the soil is governed by its angle of friction φ

In addition we will make the following assumptions

ndash The interface between the wall and the soil is frictionless

ndash The soil surface is horizontal and there are no shear stresses on horizontal and vertical planes ie The horizontal and vertical stresses are principal stresses

ndash The wall is rigid and extends to an infinite depth in a dry homogenous isotropic soil mass

ndash The soil is loose and initially in an at-rest state

9

LATERAL EARTH PRESSURE THEORY

There are two classical earth pressure theories They are

1 Coulombs earth pressure theory 2 Rankines earth pressure theory

10

THE RANKINE THEORY ASSUMES

There is no adhesion or friction between the wall and soil

Lateral pressure is limited to vertical walls Failure (in the backfill) occurs as a sliding

wedge along an assumed failure plane defined by φ

Lateral pressure varies linearly with depth and the resultant pressure is located one-third of the height (H) above the base of the wall

The resultant force is parallel to the backfill surface

11

THE COULOMB THEORY IS SIMILAR TO RANKINE EXCEPT THAT There is friction between the wall and soil

and takes this into account by using a soil-wall friction angle of δ

Note that δ ranges from φ2 to 2φ3 and δ = 2φ3 is commonly used

Lateral pressure is not limited to vertical walls

The resultant force is not necessarily parallel to the backfill surface because of the soil-wall friction value δ

12

LATERAL EARTH PRESSURE FOR AT REST CONDITION If the wall is rigid and does not move with the

pressure exerted on the wall the soil behind the wall will be in a state of elastic equilibrium

13

LATERAL EARTH PRESSURE FOR AT REST CONDITION

Element E is subjected to the following pressures

E

14

LATERAL EARTH PRESSURE FOR AT REST CONDITION If we consider the backfill is homogeneous

then v and h both increase linearly with depth z

In such a case the ratio of h to v remains constant with respect to depth that is

Where Ko is called the coefficient of earth pressure for the at rest condition or at rest earth pressure Coefficient

The lateral earth pressure h acting on the wall at any depth z may be expressed as

15

LATERAL EARTH PRESSURE FOR AT REST CONDITION

16

COEFFICIENTS OF EARTH PRESSURE FOR AT REST CONDITION KO

Type of soil Ip Ko

Loose sand saturated 046Dense sand saturated 036Dense sand dry (e = 06)

049

Loose sand dry (e = 08)

064

Compacted clay 9 042Compacted clay 31 060Organic silty clay undisturbed (w = 74)

45 057

17

FACTORS AFFECTING KO

The value of Ko depends upon the relative density of the sand and the process by which the deposit was formed

If this process does not involve artificial tamping the value of Ko ranges from about 040 for loose sand to 06 for dense sand

Tamping the layers may increase it to 08

18

DEVELOPMENT OF ACTIVE AND PASSIVE EARTH PRESSURES

19

HORIZONTAL STRESS AS A FUNCTION OF THE DISPLACEMENT

20

DEVELOPMENT OF EARTH PRESSURES

Active Pressures Overburden (σ1)Driving

Passive Pressures Wall (σ3) Driving

21

ACTIVE EARTH PRESSURE

‐ Wall moves away from soil

22

ACTIVE EARTH PRESSURE

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

7

DEFINITION OF KEY TERMS Active earth pressure coefficient (Ka) It is

the ratio of horizontal and vertical principal effective stresses when a retaining wall moves away (by a small amount) from the retained soil Passive earth pressure coefficient (Kp) It is the ratio of horizontal and vertical principal effective stresses when a retaining wall is forced against a soil mass Coefficient of earth pressure at rest (Ko) It is the ratio of horizontal and vertical principal effective stresses when the retaining wall does not move at all ie it is ldquoat restrdquo

8

LATERAL EARTH PRESSURE ndash BASIC CONCEPTS

We will consider the lateral pressure on a vertical wall that retains soil on one side

First we will consider a drained case ie The shear strength of the soil is governed by its angle of friction φ

In addition we will make the following assumptions

ndash The interface between the wall and the soil is frictionless

ndash The soil surface is horizontal and there are no shear stresses on horizontal and vertical planes ie The horizontal and vertical stresses are principal stresses

ndash The wall is rigid and extends to an infinite depth in a dry homogenous isotropic soil mass

ndash The soil is loose and initially in an at-rest state

9

LATERAL EARTH PRESSURE THEORY

There are two classical earth pressure theories They are

1 Coulombs earth pressure theory 2 Rankines earth pressure theory

10

THE RANKINE THEORY ASSUMES

There is no adhesion or friction between the wall and soil

Lateral pressure is limited to vertical walls Failure (in the backfill) occurs as a sliding

wedge along an assumed failure plane defined by φ

Lateral pressure varies linearly with depth and the resultant pressure is located one-third of the height (H) above the base of the wall

The resultant force is parallel to the backfill surface

11

THE COULOMB THEORY IS SIMILAR TO RANKINE EXCEPT THAT There is friction between the wall and soil

and takes this into account by using a soil-wall friction angle of δ

Note that δ ranges from φ2 to 2φ3 and δ = 2φ3 is commonly used

Lateral pressure is not limited to vertical walls

The resultant force is not necessarily parallel to the backfill surface because of the soil-wall friction value δ

12

LATERAL EARTH PRESSURE FOR AT REST CONDITION If the wall is rigid and does not move with the

pressure exerted on the wall the soil behind the wall will be in a state of elastic equilibrium

13

LATERAL EARTH PRESSURE FOR AT REST CONDITION

Element E is subjected to the following pressures

E

14

LATERAL EARTH PRESSURE FOR AT REST CONDITION If we consider the backfill is homogeneous

then v and h both increase linearly with depth z

In such a case the ratio of h to v remains constant with respect to depth that is

Where Ko is called the coefficient of earth pressure for the at rest condition or at rest earth pressure Coefficient

The lateral earth pressure h acting on the wall at any depth z may be expressed as

15

LATERAL EARTH PRESSURE FOR AT REST CONDITION

16

COEFFICIENTS OF EARTH PRESSURE FOR AT REST CONDITION KO

Type of soil Ip Ko

Loose sand saturated 046Dense sand saturated 036Dense sand dry (e = 06)

049

Loose sand dry (e = 08)

064

Compacted clay 9 042Compacted clay 31 060Organic silty clay undisturbed (w = 74)

45 057

17

FACTORS AFFECTING KO

The value of Ko depends upon the relative density of the sand and the process by which the deposit was formed

If this process does not involve artificial tamping the value of Ko ranges from about 040 for loose sand to 06 for dense sand

Tamping the layers may increase it to 08

18

DEVELOPMENT OF ACTIVE AND PASSIVE EARTH PRESSURES

19

HORIZONTAL STRESS AS A FUNCTION OF THE DISPLACEMENT

20

DEVELOPMENT OF EARTH PRESSURES

Active Pressures Overburden (σ1)Driving

Passive Pressures Wall (σ3) Driving

21

ACTIVE EARTH PRESSURE

‐ Wall moves away from soil

22

ACTIVE EARTH PRESSURE

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

8

LATERAL EARTH PRESSURE ndash BASIC CONCEPTS

We will consider the lateral pressure on a vertical wall that retains soil on one side

First we will consider a drained case ie The shear strength of the soil is governed by its angle of friction φ

In addition we will make the following assumptions

ndash The interface between the wall and the soil is frictionless

ndash The soil surface is horizontal and there are no shear stresses on horizontal and vertical planes ie The horizontal and vertical stresses are principal stresses

ndash The wall is rigid and extends to an infinite depth in a dry homogenous isotropic soil mass

ndash The soil is loose and initially in an at-rest state

9

LATERAL EARTH PRESSURE THEORY

There are two classical earth pressure theories They are

1 Coulombs earth pressure theory 2 Rankines earth pressure theory

10

THE RANKINE THEORY ASSUMES

There is no adhesion or friction between the wall and soil

Lateral pressure is limited to vertical walls Failure (in the backfill) occurs as a sliding

wedge along an assumed failure plane defined by φ

Lateral pressure varies linearly with depth and the resultant pressure is located one-third of the height (H) above the base of the wall

The resultant force is parallel to the backfill surface

11

THE COULOMB THEORY IS SIMILAR TO RANKINE EXCEPT THAT There is friction between the wall and soil

and takes this into account by using a soil-wall friction angle of δ

Note that δ ranges from φ2 to 2φ3 and δ = 2φ3 is commonly used

Lateral pressure is not limited to vertical walls

The resultant force is not necessarily parallel to the backfill surface because of the soil-wall friction value δ

12

LATERAL EARTH PRESSURE FOR AT REST CONDITION If the wall is rigid and does not move with the

pressure exerted on the wall the soil behind the wall will be in a state of elastic equilibrium

13

LATERAL EARTH PRESSURE FOR AT REST CONDITION

Element E is subjected to the following pressures

E

14

LATERAL EARTH PRESSURE FOR AT REST CONDITION If we consider the backfill is homogeneous

then v and h both increase linearly with depth z

In such a case the ratio of h to v remains constant with respect to depth that is

Where Ko is called the coefficient of earth pressure for the at rest condition or at rest earth pressure Coefficient

The lateral earth pressure h acting on the wall at any depth z may be expressed as

15

LATERAL EARTH PRESSURE FOR AT REST CONDITION

16

COEFFICIENTS OF EARTH PRESSURE FOR AT REST CONDITION KO

Type of soil Ip Ko

Loose sand saturated 046Dense sand saturated 036Dense sand dry (e = 06)

049

Loose sand dry (e = 08)

064

Compacted clay 9 042Compacted clay 31 060Organic silty clay undisturbed (w = 74)

45 057

17

FACTORS AFFECTING KO

The value of Ko depends upon the relative density of the sand and the process by which the deposit was formed

If this process does not involve artificial tamping the value of Ko ranges from about 040 for loose sand to 06 for dense sand

Tamping the layers may increase it to 08

18

DEVELOPMENT OF ACTIVE AND PASSIVE EARTH PRESSURES

19

HORIZONTAL STRESS AS A FUNCTION OF THE DISPLACEMENT

20

DEVELOPMENT OF EARTH PRESSURES

Active Pressures Overburden (σ1)Driving

Passive Pressures Wall (σ3) Driving

21

ACTIVE EARTH PRESSURE

‐ Wall moves away from soil

22

ACTIVE EARTH PRESSURE

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

9

LATERAL EARTH PRESSURE THEORY

There are two classical earth pressure theories They are

1 Coulombs earth pressure theory 2 Rankines earth pressure theory

10

THE RANKINE THEORY ASSUMES

There is no adhesion or friction between the wall and soil

Lateral pressure is limited to vertical walls Failure (in the backfill) occurs as a sliding

wedge along an assumed failure plane defined by φ

Lateral pressure varies linearly with depth and the resultant pressure is located one-third of the height (H) above the base of the wall

The resultant force is parallel to the backfill surface

11

THE COULOMB THEORY IS SIMILAR TO RANKINE EXCEPT THAT There is friction between the wall and soil

and takes this into account by using a soil-wall friction angle of δ

Note that δ ranges from φ2 to 2φ3 and δ = 2φ3 is commonly used

Lateral pressure is not limited to vertical walls

The resultant force is not necessarily parallel to the backfill surface because of the soil-wall friction value δ

12

LATERAL EARTH PRESSURE FOR AT REST CONDITION If the wall is rigid and does not move with the

pressure exerted on the wall the soil behind the wall will be in a state of elastic equilibrium

13

LATERAL EARTH PRESSURE FOR AT REST CONDITION

Element E is subjected to the following pressures

E

14

LATERAL EARTH PRESSURE FOR AT REST CONDITION If we consider the backfill is homogeneous

then v and h both increase linearly with depth z

In such a case the ratio of h to v remains constant with respect to depth that is

Where Ko is called the coefficient of earth pressure for the at rest condition or at rest earth pressure Coefficient

The lateral earth pressure h acting on the wall at any depth z may be expressed as

15

LATERAL EARTH PRESSURE FOR AT REST CONDITION

16

COEFFICIENTS OF EARTH PRESSURE FOR AT REST CONDITION KO

Type of soil Ip Ko

Loose sand saturated 046Dense sand saturated 036Dense sand dry (e = 06)

049

Loose sand dry (e = 08)

064

Compacted clay 9 042Compacted clay 31 060Organic silty clay undisturbed (w = 74)

45 057

17

FACTORS AFFECTING KO

The value of Ko depends upon the relative density of the sand and the process by which the deposit was formed

If this process does not involve artificial tamping the value of Ko ranges from about 040 for loose sand to 06 for dense sand

Tamping the layers may increase it to 08

18

DEVELOPMENT OF ACTIVE AND PASSIVE EARTH PRESSURES

19

HORIZONTAL STRESS AS A FUNCTION OF THE DISPLACEMENT

20

DEVELOPMENT OF EARTH PRESSURES

Active Pressures Overburden (σ1)Driving

Passive Pressures Wall (σ3) Driving

21

ACTIVE EARTH PRESSURE

‐ Wall moves away from soil

22

ACTIVE EARTH PRESSURE

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

10

THE RANKINE THEORY ASSUMES

There is no adhesion or friction between the wall and soil

Lateral pressure is limited to vertical walls Failure (in the backfill) occurs as a sliding

wedge along an assumed failure plane defined by φ

Lateral pressure varies linearly with depth and the resultant pressure is located one-third of the height (H) above the base of the wall

The resultant force is parallel to the backfill surface

11

THE COULOMB THEORY IS SIMILAR TO RANKINE EXCEPT THAT There is friction between the wall and soil

and takes this into account by using a soil-wall friction angle of δ

Note that δ ranges from φ2 to 2φ3 and δ = 2φ3 is commonly used

Lateral pressure is not limited to vertical walls

The resultant force is not necessarily parallel to the backfill surface because of the soil-wall friction value δ

12

LATERAL EARTH PRESSURE FOR AT REST CONDITION If the wall is rigid and does not move with the

pressure exerted on the wall the soil behind the wall will be in a state of elastic equilibrium

13

LATERAL EARTH PRESSURE FOR AT REST CONDITION

Element E is subjected to the following pressures

E

14

LATERAL EARTH PRESSURE FOR AT REST CONDITION If we consider the backfill is homogeneous

then v and h both increase linearly with depth z

In such a case the ratio of h to v remains constant with respect to depth that is

Where Ko is called the coefficient of earth pressure for the at rest condition or at rest earth pressure Coefficient

The lateral earth pressure h acting on the wall at any depth z may be expressed as

15

LATERAL EARTH PRESSURE FOR AT REST CONDITION

16

COEFFICIENTS OF EARTH PRESSURE FOR AT REST CONDITION KO

Type of soil Ip Ko

Loose sand saturated 046Dense sand saturated 036Dense sand dry (e = 06)

049

Loose sand dry (e = 08)

064

Compacted clay 9 042Compacted clay 31 060Organic silty clay undisturbed (w = 74)

45 057

17

FACTORS AFFECTING KO

The value of Ko depends upon the relative density of the sand and the process by which the deposit was formed

If this process does not involve artificial tamping the value of Ko ranges from about 040 for loose sand to 06 for dense sand

Tamping the layers may increase it to 08

18

DEVELOPMENT OF ACTIVE AND PASSIVE EARTH PRESSURES

19

HORIZONTAL STRESS AS A FUNCTION OF THE DISPLACEMENT

20

DEVELOPMENT OF EARTH PRESSURES

Active Pressures Overburden (σ1)Driving

Passive Pressures Wall (σ3) Driving

21

ACTIVE EARTH PRESSURE

‐ Wall moves away from soil

22

ACTIVE EARTH PRESSURE

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

11

THE COULOMB THEORY IS SIMILAR TO RANKINE EXCEPT THAT There is friction between the wall and soil

and takes this into account by using a soil-wall friction angle of δ

Note that δ ranges from φ2 to 2φ3 and δ = 2φ3 is commonly used

Lateral pressure is not limited to vertical walls

The resultant force is not necessarily parallel to the backfill surface because of the soil-wall friction value δ

12

LATERAL EARTH PRESSURE FOR AT REST CONDITION If the wall is rigid and does not move with the

pressure exerted on the wall the soil behind the wall will be in a state of elastic equilibrium

13

LATERAL EARTH PRESSURE FOR AT REST CONDITION

Element E is subjected to the following pressures

E

14

LATERAL EARTH PRESSURE FOR AT REST CONDITION If we consider the backfill is homogeneous

then v and h both increase linearly with depth z

In such a case the ratio of h to v remains constant with respect to depth that is

Where Ko is called the coefficient of earth pressure for the at rest condition or at rest earth pressure Coefficient

The lateral earth pressure h acting on the wall at any depth z may be expressed as

15

LATERAL EARTH PRESSURE FOR AT REST CONDITION

16

COEFFICIENTS OF EARTH PRESSURE FOR AT REST CONDITION KO

Type of soil Ip Ko

Loose sand saturated 046Dense sand saturated 036Dense sand dry (e = 06)

049

Loose sand dry (e = 08)

064

Compacted clay 9 042Compacted clay 31 060Organic silty clay undisturbed (w = 74)

45 057

17

FACTORS AFFECTING KO

The value of Ko depends upon the relative density of the sand and the process by which the deposit was formed

If this process does not involve artificial tamping the value of Ko ranges from about 040 for loose sand to 06 for dense sand

Tamping the layers may increase it to 08

18

DEVELOPMENT OF ACTIVE AND PASSIVE EARTH PRESSURES

19

HORIZONTAL STRESS AS A FUNCTION OF THE DISPLACEMENT

20

DEVELOPMENT OF EARTH PRESSURES

Active Pressures Overburden (σ1)Driving

Passive Pressures Wall (σ3) Driving

21

ACTIVE EARTH PRESSURE

‐ Wall moves away from soil

22

ACTIVE EARTH PRESSURE

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

12

LATERAL EARTH PRESSURE FOR AT REST CONDITION If the wall is rigid and does not move with the

pressure exerted on the wall the soil behind the wall will be in a state of elastic equilibrium

13

LATERAL EARTH PRESSURE FOR AT REST CONDITION

Element E is subjected to the following pressures

E

14

LATERAL EARTH PRESSURE FOR AT REST CONDITION If we consider the backfill is homogeneous

then v and h both increase linearly with depth z

In such a case the ratio of h to v remains constant with respect to depth that is

Where Ko is called the coefficient of earth pressure for the at rest condition or at rest earth pressure Coefficient

The lateral earth pressure h acting on the wall at any depth z may be expressed as

15

LATERAL EARTH PRESSURE FOR AT REST CONDITION

16

COEFFICIENTS OF EARTH PRESSURE FOR AT REST CONDITION KO

Type of soil Ip Ko

Loose sand saturated 046Dense sand saturated 036Dense sand dry (e = 06)

049

Loose sand dry (e = 08)

064

Compacted clay 9 042Compacted clay 31 060Organic silty clay undisturbed (w = 74)

45 057

17

FACTORS AFFECTING KO

The value of Ko depends upon the relative density of the sand and the process by which the deposit was formed

If this process does not involve artificial tamping the value of Ko ranges from about 040 for loose sand to 06 for dense sand

Tamping the layers may increase it to 08

18

DEVELOPMENT OF ACTIVE AND PASSIVE EARTH PRESSURES

19

HORIZONTAL STRESS AS A FUNCTION OF THE DISPLACEMENT

20

DEVELOPMENT OF EARTH PRESSURES

Active Pressures Overburden (σ1)Driving

Passive Pressures Wall (σ3) Driving

21

ACTIVE EARTH PRESSURE

‐ Wall moves away from soil

22

ACTIVE EARTH PRESSURE

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

13

LATERAL EARTH PRESSURE FOR AT REST CONDITION

Element E is subjected to the following pressures

E

14

LATERAL EARTH PRESSURE FOR AT REST CONDITION If we consider the backfill is homogeneous

then v and h both increase linearly with depth z

In such a case the ratio of h to v remains constant with respect to depth that is

Where Ko is called the coefficient of earth pressure for the at rest condition or at rest earth pressure Coefficient

The lateral earth pressure h acting on the wall at any depth z may be expressed as

15

LATERAL EARTH PRESSURE FOR AT REST CONDITION

16

COEFFICIENTS OF EARTH PRESSURE FOR AT REST CONDITION KO

Type of soil Ip Ko

Loose sand saturated 046Dense sand saturated 036Dense sand dry (e = 06)

049

Loose sand dry (e = 08)

064

Compacted clay 9 042Compacted clay 31 060Organic silty clay undisturbed (w = 74)

45 057

17

FACTORS AFFECTING KO

The value of Ko depends upon the relative density of the sand and the process by which the deposit was formed

If this process does not involve artificial tamping the value of Ko ranges from about 040 for loose sand to 06 for dense sand

Tamping the layers may increase it to 08

18

DEVELOPMENT OF ACTIVE AND PASSIVE EARTH PRESSURES

19

HORIZONTAL STRESS AS A FUNCTION OF THE DISPLACEMENT

20

DEVELOPMENT OF EARTH PRESSURES

Active Pressures Overburden (σ1)Driving

Passive Pressures Wall (σ3) Driving

21

ACTIVE EARTH PRESSURE

‐ Wall moves away from soil

22

ACTIVE EARTH PRESSURE

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

14

LATERAL EARTH PRESSURE FOR AT REST CONDITION If we consider the backfill is homogeneous

then v and h both increase linearly with depth z

In such a case the ratio of h to v remains constant with respect to depth that is

Where Ko is called the coefficient of earth pressure for the at rest condition or at rest earth pressure Coefficient

The lateral earth pressure h acting on the wall at any depth z may be expressed as

15

LATERAL EARTH PRESSURE FOR AT REST CONDITION

16

COEFFICIENTS OF EARTH PRESSURE FOR AT REST CONDITION KO

Type of soil Ip Ko

Loose sand saturated 046Dense sand saturated 036Dense sand dry (e = 06)

049

Loose sand dry (e = 08)

064

Compacted clay 9 042Compacted clay 31 060Organic silty clay undisturbed (w = 74)

45 057

17

FACTORS AFFECTING KO

The value of Ko depends upon the relative density of the sand and the process by which the deposit was formed

If this process does not involve artificial tamping the value of Ko ranges from about 040 for loose sand to 06 for dense sand

Tamping the layers may increase it to 08

18

DEVELOPMENT OF ACTIVE AND PASSIVE EARTH PRESSURES

19

HORIZONTAL STRESS AS A FUNCTION OF THE DISPLACEMENT

20

DEVELOPMENT OF EARTH PRESSURES

Active Pressures Overburden (σ1)Driving

Passive Pressures Wall (σ3) Driving

21

ACTIVE EARTH PRESSURE

‐ Wall moves away from soil

22

ACTIVE EARTH PRESSURE

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

15

LATERAL EARTH PRESSURE FOR AT REST CONDITION

16

COEFFICIENTS OF EARTH PRESSURE FOR AT REST CONDITION KO

Type of soil Ip Ko

Loose sand saturated 046Dense sand saturated 036Dense sand dry (e = 06)

049

Loose sand dry (e = 08)

064

Compacted clay 9 042Compacted clay 31 060Organic silty clay undisturbed (w = 74)

45 057

17

FACTORS AFFECTING KO

The value of Ko depends upon the relative density of the sand and the process by which the deposit was formed

If this process does not involve artificial tamping the value of Ko ranges from about 040 for loose sand to 06 for dense sand

Tamping the layers may increase it to 08

18

DEVELOPMENT OF ACTIVE AND PASSIVE EARTH PRESSURES

19

HORIZONTAL STRESS AS A FUNCTION OF THE DISPLACEMENT

20

DEVELOPMENT OF EARTH PRESSURES

Active Pressures Overburden (σ1)Driving

Passive Pressures Wall (σ3) Driving

21

ACTIVE EARTH PRESSURE

‐ Wall moves away from soil

22

ACTIVE EARTH PRESSURE

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

16

COEFFICIENTS OF EARTH PRESSURE FOR AT REST CONDITION KO

Type of soil Ip Ko

Loose sand saturated 046Dense sand saturated 036Dense sand dry (e = 06)

049

Loose sand dry (e = 08)

064

Compacted clay 9 042Compacted clay 31 060Organic silty clay undisturbed (w = 74)

45 057

17

FACTORS AFFECTING KO

The value of Ko depends upon the relative density of the sand and the process by which the deposit was formed

If this process does not involve artificial tamping the value of Ko ranges from about 040 for loose sand to 06 for dense sand

Tamping the layers may increase it to 08

18

DEVELOPMENT OF ACTIVE AND PASSIVE EARTH PRESSURES

19

HORIZONTAL STRESS AS A FUNCTION OF THE DISPLACEMENT

20

DEVELOPMENT OF EARTH PRESSURES

Active Pressures Overburden (σ1)Driving

Passive Pressures Wall (σ3) Driving

21

ACTIVE EARTH PRESSURE

‐ Wall moves away from soil

22

ACTIVE EARTH PRESSURE

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

17

FACTORS AFFECTING KO

The value of Ko depends upon the relative density of the sand and the process by which the deposit was formed

If this process does not involve artificial tamping the value of Ko ranges from about 040 for loose sand to 06 for dense sand

Tamping the layers may increase it to 08

18

DEVELOPMENT OF ACTIVE AND PASSIVE EARTH PRESSURES

19

HORIZONTAL STRESS AS A FUNCTION OF THE DISPLACEMENT

20

DEVELOPMENT OF EARTH PRESSURES

Active Pressures Overburden (σ1)Driving

Passive Pressures Wall (σ3) Driving

21

ACTIVE EARTH PRESSURE

‐ Wall moves away from soil

22

ACTIVE EARTH PRESSURE

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

18

DEVELOPMENT OF ACTIVE AND PASSIVE EARTH PRESSURES

19

HORIZONTAL STRESS AS A FUNCTION OF THE DISPLACEMENT

20

DEVELOPMENT OF EARTH PRESSURES

Active Pressures Overburden (σ1)Driving

Passive Pressures Wall (σ3) Driving

21

ACTIVE EARTH PRESSURE

‐ Wall moves away from soil

22

ACTIVE EARTH PRESSURE

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

19

HORIZONTAL STRESS AS A FUNCTION OF THE DISPLACEMENT

20

DEVELOPMENT OF EARTH PRESSURES

Active Pressures Overburden (σ1)Driving

Passive Pressures Wall (σ3) Driving

21

ACTIVE EARTH PRESSURE

‐ Wall moves away from soil

22

ACTIVE EARTH PRESSURE

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

20

DEVELOPMENT OF EARTH PRESSURES

Active Pressures Overburden (σ1)Driving

Passive Pressures Wall (σ3) Driving

21

ACTIVE EARTH PRESSURE

‐ Wall moves away from soil

22

ACTIVE EARTH PRESSURE

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

21

ACTIVE EARTH PRESSURE

‐ Wall moves away from soil

22

ACTIVE EARTH PRESSURE

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

22

ACTIVE EARTH PRESSURE

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

23

PASSIVE EARTH PRESSURE

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

24

PASSIVE EARTH PRESSURE

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

25

MOVEMENT REQUIRED TO DEVELOP ACTIVE EARTH PRESSURE

Soil Type amp Condition

H Required

Sands Granular soilDense 0001 H to 0002H

loose 0002 H to 0004 H

ClaysStiffHard 001H to 002 HSoft material 002 H to 005H

H

H

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

26

RANKINES EARTH PRESSURE THEORIES

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

27

RANKINES CONDITION FOR ACTIVE AND PASSIVE FAILURES IN A SEMI-INFINITE MASS OF COHESIONLESS SOIL

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

28

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

29

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

30

SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL Backfill Horizontal-Active Earth Pressure

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

31

Backfill Horizontal-Passive Earth Pressure

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

32

RANKINErsquoS THEORY PASSIVE EARTH PRESSURE

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

33

Relationship between Kp and KA

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

34

RANKINErsquoS THEORY ACTIVE EARTH PRESSURE

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

35

TENSION CRACK IN SOIL

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

36

RANKINES ACTIVE PRESSURE UNDER SUBMERGED CONDITION IN COHESION LESS SOIL

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

37

RANKINES ACTIVE PRESSURE IN COHESIONLESS BACKFILL UNDER PARTLY SUBMERGED CONDITION WITH SURCHARGE LOAD

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

38

RANKINES ACTIVE PRESSURE FOR A SLOPING COHESIONLESS BACKFILL

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

39

MOHR DIAGRAM

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

40

RANKINES PASSIVE PRESSURE IN SLOPING COHESIONLESS BACKFILL

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

41

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

42

RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

43

ACTIVE EARTH PRESSURE ON VERTICAL SECTIONS IN COHESIVE SOILS

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

44

EFFECT OF WATER TABLE ON LATERAL EARTH PRESSURE

NΦ = tan2 (45+Φ2)

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

45

RANKINErsquoS THEORY SPECIAL CASES

σh = K aσv prime + uσvlsquo= σv-uu= pore water pressureSubmergence

Inclined Backfill

Inclined but Smooth Back face of wall

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

46

COULOMBS EARTH PRESSURE THEORY

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

47

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE

Coulomb made the following assumptions in the development of his theory

1 The soil is isotropic and homogeneous

2 The rupture surface is a plane surface 3 The failure wedge is a rigid body 4 The pressure surface is a plane

surface 5 There is wall friction on the pressure

surface 6 Failure is two-dimensional and 7 The soil is cohesionless

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

48

CONDITIONS FOR FAILURE UNDER ACTIVE CONDITIONS

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

49

PROCEDURE TO DRAW ABC

1 AB is the pressure face2 The backfill surface BE is a plane inclined at

an angle with the horizontal3 is the angle made by the pressure face AB

with the horizontal4 H is the height of the wall5 AC is the assumed rupture plane surface

and6 is the angle made by the surface AC with

the horizontal7 W = yA where A = area of wedge ABC

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

50

ACTIVE EARTH PRESSURE

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

51

COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

52

COULOMBrsquoS THEORY PASSIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryoverestimatesPassive EP

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

53

COULOMBrsquoS THEORY ACTIVE EARTH PRESSURE ( GRAPHICAL METHOD)

Wall Friction

CoulombrsquostheoryunderestimatesActive EP

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

54

COULOMBrsquoS THEORY SOLUTIONS

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

55

CULMANNrsquoS GRAPHICAL METHOD ACTIVE EP

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

56

CULMANNrsquoS GRAPHICAL METHOD PASSIVE EP

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

57

PRESSURE DISTRIBUTION FOR STRATIFIEDSOILS

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

58

THE LOCATION OF STRUTS AFFECTS THE VALUES AND DISTRIBUTIONS OF LATERAL EARTH PRESSURES

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

59

MODES OF GEOTECHNICAL FAILURES

Sliding Overturning

Bearing

Overall Stability Settlement

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

60

LATERAL SUPPORT

Gravity Retainingwall

Soil nailing Reinforced earth wall

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

61

SOIL NAILING

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

62

SHEET PILE

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

63

THE MAGNITUDE OF LATERAL EARTH PRESSURE DEPENDS ON Shear strength characteristics of soil 2 Lateral strain condition 3 Pore water pressure 4 State of Equilibrium of soil 5 Wall and ground surface shape

Previous conditions depends mainly on a) Drainage conditions b) Interaction between soil and wall

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

64

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

65

WALL DRAINAGEAccumulation of rain water in the back fill results in its saturation and thus a considerable increase in the earth pressure acting on the wallThis may eventually lead to unstable conditions Two of the options to take care of this problem are the following1048709 Provision of weep holes wo geo-textile on the back-face of wall1048709 Perforated pipe draining system with filter

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

66

WALL DRAINAGEWeep Holes They should have a minimumdiameter of 10 cm and be adequately spaced depending on the backfill material Geotextile material or a thin layer of some other filter may be used on the back face of wall for the full height in order to avoid the back fill material entering the weep holes and eventually clogging them

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

67

GABION RETAINING WALL

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

68

REFERANCES1 Soil Mecahnics amp Foundation Engg -

Arora2 Soil Mechanics ndash VNSMurthy3 wwwwikipediacom

69Any Question

• LATERAL EARTH PRESSURE Guest Lecture Sal Collage of Enginee
• Where Earth Pressure
• Types of Retaining Walls
• Use of retaining walls
• Use of retaining walls
• In geotechnical engineering it is often necessary to prevent
• Definition of Key Terms
• Lateral Earth Pressure ndash Basic Concepts
• LATERAL EARTH PRESSURE THEORY
• The Rankine Theory assumes
• The Coulomb Theory is similar to Rankine except that
• LATERAL EARTH PRESSURE FOR AT REST CONDITION
• Lateral earth pressure for at rest condition
• Lateral earth pressure for at rest condition (2)
• Lateral earth pressure for at rest condition (3)
• Coefficients of earth pressure for at rest condition Ko
• Factors affecting Ko
• Development of active and passive earth pressures
• Horizontal stress as a function of the displacement
• Development of Earth Pressures
• Active Earth Pressure
• Active Earth Pressure (2)
• Passive Earth Pressure
• Passive Earth Pressure (2)
• Movement required to develop Active Earth Pressure
• RANKINES EARTH PRESSURE THEORIES
• Rankines condition for active and passive failures in a semi-i
• Slide 28
• Rankinersquos Theory Active Earth Pressure
• SMOOTH VERTICAL WALL WITH COHESIONLESS BACKFILL
• Slide 31
• Rankinersquos Theory Passive Earth Pressure
• Slide 33
• Rankinersquos Theory Active Earth Pressure (2)
• Tension Crack in Soil
• Rankines active pressure under submerged condition in cohesion
• Rankines active pressure in cohesionless backfill under partly
• Rankines active pressure for a sloping cohesionless backfill
• Mohr diagram
• Rankines passive pressure in sloping cohesionless backfill
• RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL
• RANKINES ACTIVE EARTH RESSURE WITH COHESIVE BACKFILL (2)
• Active earth pressure on vertical sections in cohesive soils
• Effect of water table on lateral earth pressure
• Rankinersquos Theory Special Cases
• COULOMBS EARTH PRESSURE THEORY
• COULOMBS EARTH PRESSURE THEORY FOR SAND FOR ACTIVE STATE
• Conditions for failure under active conditions
• Procedure to draw ABC
• Active Earth Pressure
• COULOMBS EARTH PRESSURE THEORY FOR SAND FOR PASSIVE STATE
• Coulombrsquos Theory Passive Earth Pressure ( Graphical Method)
• Coulombrsquos Theory Active Earth Pressure ( Graphical Method)
• Coulombrsquos Theory Solutions
• Culmannrsquos Graphical Method Active EP
• Culmannrsquos Graphical Method Passive EP
• Pressure Distribution for Stratified Soils
• The location of struts affects the values and distributions of
• Modes of Geotechnical Failures
• Lateral Support
• Soil Nailing
• Slide 62
• The magnitude of lateral earth pressure depends on
• Slide 64
• Wall Drainage
• Wall Drainage (2)
• Gabion Retaining Wall
• REFERANCES
• Slide 69