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Experiment No.1
NATURAL AND HYGROSCOPIC MOISTURE CONTENT
OBJECT: Study of determination of natural and hygroscopic water content.
APPARATUS REQUIRED:- (i) Balance accurate to 0.1 g (ii) Non-corrodible airtight
containers (iii) A Dissector with any desiccating agent other than sulphuric acid (iv)
Thermostatically controlled oven with interior of non corroding material to maintain the
temperature between 105 and 11 0 degrees.
THEORY:- Water present in the voids of a soil mass is called as soil water or the
moisture content. The hygroscopic water or contact moisture is the moisture which the
soil particles adsorb from atmosphere by physical forces of attraction. The property of soil
depends upon the moisture content of soil. It is pre-requisite for many other tests. Higher the
temperature less shall be the hygroscopic moisture content. Coarse gained soils have
relatively low hygroscopic moisture due to their limited specific surface. The maximum
hygroscopic capacity of various soils, i.e., the ratio of water absorbed by a dry soil in
saturated
atmosphere at a given temperature to the weight of the oven dried soil has approximately the
following average values; Sands-1.0%, Silts- 7% and clays- 17%.
For determination of moisture content of a soil, the soil sample selected depends upon
the quantity required for good representation, which is influenced by the gradation and
maximum size of particles, and on the accuracy of weighing. The following quantities are
recommended for general lab use:
Size of particles Max quantity of sample, wt in g
Passing 425-micron IS Sieve 25
Passing 2-mm IS Sieve 50
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Passing 4.75-mm IS Sieve 200
Passing 1 0-mm IS Sieve 1000
Passing 20-mm IS Sieve 2000
Passing 40-mm IS Sieve 5000
Drier the soil higher shall be the weight of the soil taken.
PROCEDURE: The following procedure is adopted to determine the specific gravity of soil:
1. A clean non-corrodible container is weighed with lid, W1.
2. Take a moist soil sample. Place it in container and weigh again with lid, W2.
3. Place the container with soil sample in an oven for drying. The temperature should be
105- 110 degrees because higher temperature may break the crystalline structure
of clay particles and result in- loss of chemically bound water of crystallization.
Lower temperature is recommended for organic soils to avoid oxidation of organic
matter present in the sample. In case of sandy soil complete drying can be achieved in
4 to 6 hours. However, in routine practice samples are dried for 24 hours.
4. After 24 hrs sample is taken out from the oven and placed in desiccators for cooling.
5. The container with dried soil is weighed say, W3.
6. The sample is then left open to the atmosphere so that it absorbs the moisture from the
atmosphere say, W4.
CALCULATION: - The percentage moisture content is calculated as follows:
Moisture content, W = [(W2-W3)/ (W3-W1)]*100
Weight of water, Ww = W2-W3
Weight of solids Ws = W3-W1
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Hygroscopic Moisture content = [(W4-W3)/ (W3-W1)]*100
Experiment No.2
LIQUID LIMIT BY CASSAGRANDE APPARATUS
OBJECT: - Study of determination liquid limit of soil using Casegrande Apparatus [IS: 2720
Part V-1985).
APPARATUS:-
(i) Mechanical Liquid limit device:- It consists of a brass cup and carnage, the base
of the device shall be of macerate Number 221 A.
(ii) Grooving Tool:- It is used for making a groove of standard size so as to fill it
while giving the soil filled in the cup a number of blows from a standard height of
1 cm.
(iii) Porcelain evaporating dish: -A porcelain-evaporating dish of about 12 cm
diameters is used for making the soil paste.
(iv) Spatula: - A flexible spatula with the blade about 8 cm long and 2 cm wide is used
for working with the soil.
(v) Balance: - A balance of capacity 200 g and sensitivity of 0.01 g is required to
weigh the soil sample.
(vi) Oven: Thermostatically controlled with interior of non-corroding material to
maintain the temperature between 105 and 110 C.
(vii) Container:- Airtight containers to determine the moisture content are required.
(viii) A 425-micron sieve
(ix) Desiccators
(x) Wash bottle containing distilled water.
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SOIL SPECIMEN:- A specimen weighing about 120 g from the thoroughly mixed portion of
the material passing 425micron IS Sieve is taken.
THEORY:- Liquid limit (Wl) is the water content corresponding to the arbitrary limit
between liquid and plastic state of consistency of soil. It may be defined as the minimum
moisture content at which the soil is still in liquid state but having a small shearing
strength against flowing, which can be measured by standard available means. At liquid
limit all soils possess certain small shear strength. This arbitrarily chosen shear strength
is probably the smallest value that is feasible to measure in a standardised procedure.
PROCEDURE:-
Adjustment of the mechanical device:-
The liquid limit device shall be inspected to determine that it is clean, dry and in
good working order, that the cup falls freely and it does not have too much side play at its
hinge. The grooving tool shall also be inspected to determine that it is clean, dry and the
critical dimension is as shown in the figure. By means of the gauge on the handle of the
grooving tool and the adjustment plate, the height through which the cup is lifted and
dropped shall be adjusted so that the point on the cup which comes in contact with the
base fall through exactly one centimeter for one revolution of the handle. The adjustment
plate shall then be secured by tightening the screw.
i. Take about 120 g of air-dried soil from thoroughly mixed portion of the material
passing 425 micron Sieve and mix it with distilled water in an evaporating desiccators
or on a glass plate. Leave the soil for sufficient time so that water may permeate
throughout the soil mass. In case of fat clays, this maturing time may be taken as 24
hours. For an average soil, thorough mixing for about 15 to 30 minutes may be
sufficient. Certain soils may require as much as 40 minutes of continuous mixing
immediately before testing. The prepared paste shall have a consistency that will
require 30-35 drops of the cup.
ii. Take a portion of the paste with the spatula and place it in the center of the cup so that
it is almost half filled. Level off the top of the wet soil symmetrically with the
spatula, so that it is parallel to the rubber base and the maximum depth of the soil is 1 4
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cm.
(a) Determination of mass of Sand in the cone 1 2
I. Mass of sand and cylinder before pouring (g)
2. Mean mass of sand in the cone (g)
(b) Determination of bulk density of sand
3. Volume of calibrating container (cm3)
4. Mean mass of sand and cylinder after pouring in the container (g)
5. Mass of sand tilling the calibrating container (g)M=M1-M3-M2
6. Bulk density of sand pHs = M/V
(C) Bulk density and unit weight of in situ soil
7 Mass of wet oil from the hole (g)
8. Mass sand and cylinder after po11ring in the hole
9. Mass of sand in the hole M, M1-M2-M(g)
10. Bulk density of soil p = M*ps/M in g/cm3
11. Bulk unit weight γv = 9.81 p
(d) Water content determination -
12. Container No.
13. Mass of container + wet soil (g)
14 Mass of container + dry soil (g)
15. Mass of container (g)
16. Mass of dry soil (g)= (13) -(14)
17. Mass of water (g)= (13) - (15)
18 Moisture content t w = r(16)/(17)*100
19 Specific Gravity (G)
20 Void Ratio (e) (19)/
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Experiment No.3
PERMEABILITY BY CONSTANT HEAD
OBJECT:- Study of determination of Coefficient of Permeability by Constant Head Method
[IS: 2720 (part XVII)-1966]
APPARATUS REQUIRED:-
(i) Permeameter Mould: - Non-corrodible material having a capacity of 1000 ml with an
internal diameter of 100 ± 0.1 mm and an internal effective height of 127.3 ± 0-1 mm
(ng.l ). The mould is fitted with a detachable base plate and a removable collar
approximately 60 mm high (Fig.2). The internal surface of the mould should be
smooth. The maximum particle size in the soil to be tested in this mould should be 10
mm. For bigger soil particles a bigger mould is used.
(ii) Compaction Equipment:- (a) For Dynamic Compaction:- 50 mm diameter circular
face, weight 2.6 kg and height of fail 310 mm (b) 50 mm diameter circular face,
weight 4.89 kg and height of fall 450 mm.
(iii) Drainage Base:- A base with a porous disc, 12 mm thick having a fitting for
connection to water inlet or outlet (Fig.3). The permeability of the disc should be
more than 10 times the expected permeability of soil. The base should also be
provided with a dummy plate (Fig.4) 12 mm thick and 108 mm in diameter Which to
be used in the place of the porous stone when the soil specimen is compacted in the
mould.
(iv) Drainage Cap:- A cap with an inserted porous dia., 12 mm thick having fitting for
connection to water inlet and outlet (Fig.5). The permeability of the disc should be
more than 10 times the expected permeability of soil. The drainage base and cap
should have fittings for being clamped to the permearneter mould. They should be
provided with leak-proof seals such as rubber 0-rings or gaskets (Fig.6). The
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apparatus should be such that there is no gap between the soil specimen and the top
and bottom porous discs when it is assembled ready for the test.
(v) Constant Head Tank:- A suitable water reservoir capable of supplying water to the
Permeameter.
(vi) Vacuum pump
(vii) Miscellaneous Apparatus:- IS Sieves 4.75 mm, mixing pan, graduated cylinder, meter
scale, stop watch, thermometer and de-aired water.
THEORY:- The ease with which water can flow through a saturated soil is known as
permeability. The consolidation process (the rate of settlement of day) depends upon its
permeability. The Knowledge of this property is essential in the solution of problems
involving dewatering, yield of water bearing strata, seepage through earth dams, stability of
earthen dams, and embankments as affected by seepage, settlement, etc. The quantity of
stored water escaping through and beneath an earthen dam depends upon the permeability of
embankment and foundations respectively present in the voids of a soil mass is called as soil
water or the moisture. Coefficient of permeability or simply permeability is usually evaluated
on the basis of Darcy law, which states that the rate of flow through a porous medium is
proportional to the hydraulic gradient. For this law to be valid the flow through soil should be
laminar. This method i.e. Constant Head Method is usually used for predominantly sandy
soils.
PREPARATION OF TEST SPECIMEN:-
(a) Disturbed Sample: - A 2.5 kg sample is taken from a thoroughly mixed air-dried or
oven-dried material. The moisture content is determined (Experiment No.1). The
sample is placed in an airtight container. The desired amount of water (either the
OMC or any specified moisture content) is added to the stored sample soil Spread
evenly over the sample, and after thorough mixing: the material is again placed in the
storage container. The permeameter mould is weighed empty to the nearest gram.
After greasing lightly the inside of the mould it is damped between the compaction
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base plate and extension collar. The assembly is kept on & solid base.
All dimensions are in millimeter
DRAINAGE BASE
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NOTE:-All dimensions are in millimeters, unless otherwise specified. The dimensional tolerance is ± 1 mm to match the assembly.
EXTENSION COLLAR
The dry density for remoulded soil sample is either MOD as found from Proctor
Compaction test, field density or any other density at which the test is desired- The amount
of oven-dried soil required can be calculated as W =yd*V (V = volume of the mould, Yd
= required density). The amount of water is evaluated by multiplying this with moisture
content (in fraction). The corn active effort may be varied to simulate field conditions. Static
compaction may also be used wherever necessary. For this, attach the 3 cm collar to the
bottom end of the 0.3 liter mould and 2.5 cm collar to its top end. Support the mould
assembly over the 2.5 cm end plug with the 2.5 cm collar resting on the split collar kept
around the 2.5 cm end plug. The 0 3 liter mould should be lightly greased from inside. After
completion of compaction the collar is removed and excess soil is trimmed level with the top
of the mould. The base is detached and the mould full of compacted specimen is weighed.
The mould with the specimen inside is assembled to the drainage base and cap having porous
discs as shown in Fig 6. The porous discs are saturated before assembling the mould.
(b) Undisturbed Sample:- Undisturbed specimen is trimmed in the form-of a cylinder not
larger than about 85 mm diameter and height equal to that of mould. The specimen is placed
centrally over the porous disc of the drainage base fixed to the mould. The annular space
between the mould and the specimen is filled with an impervious material such as cement
slurry or a mixture of 10% dry powdered Bentonite and 90% fine sand by weight to provide
sealing between the soil Specimen and the mould against leakage from the sides. When using
cement slurry the mould is kept on a flat surface other than the porous discs. The drainage
cap is then fixed over the top of the mould
TEST PROCEDURE:-
Saturation: - In case of soils of medium to high permeability the specimen is subjected to
sufficient head, flow or immersion so as to obtain full saturation. Soils of low permeability
require flow under High head for periods ranging from a" day to a week depending upon the
permeability and head. Alternately, in the case of soils having low permeability the specimen
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is subjected to a gradually increasing vacuum with bottom outlet dosed so as to remove
air from the soil voids. The vacuum is increased to at least 70 cm of mercury, which is
maintained for 15 minutes or more depending upon the type of soil. Then a very slow
saturation of the specimen with de-aired water from the bottom upwards under full vacuum is
done. When the specimen is saturated both the top and bottom outlets are closed.
Now the specimen is connected through the top inlet to the constant head reservoir.
The bottom outlet is opened and when the steady state of flow has been established, the
quantity of flow for a convenient time intervals is collected and weighed or measured.
Alternatively, the inlet may be at the bottom and water may be collected from the outlet at
top. The collection of the quantity of flow for the same time interval is repeated thrice.
Note I:- In order to ensure laminar flow condition, Cohesion less soils are to be tested under
a low hydraulic gradient, which may be from 0.2 to 0.3 for loose state of compact less and
from 0.3 to 0.5 for denser state of compactness. Coarser the soil the lower shall be the
hydraulic gradient used in the test.
Note II:- De-aired water is used for the test.
OBSERVATION:-
Sample No.
Date
Time
Location of Sample
Bore No.
Depth
Diameter of specimen, in cm =
Length of Specimen (L) in cm =
Area of specimen (A), in cm2 =
Volume of specimen (V) in cm3 =
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Specific Gravity of soil (G) =
Tare No. =
Weight of wet soil specimen after test, in g =
Weight of Tare, in g =
Moisture content, w =
Weight of dry specimen + Tare, in g =
Weight of dry specimen. W s in g =
Degree of saturation at the end of test in % =
CALCULATIONS:-
The coefficient of permeability may be obtained from the following equation k =
(Q*L)/(A*h) Where,
k = Coefficient of permeability in cm/s,
G-Rate of low in cm3/s,
Quantity collected in cm3/Time interval in seconds,
L = Length of specimen in cm,
A= Cross sectional area of specimen in cm2,
h = Constant hydraulic head causing the flow in cm,
The temperature correction is applied by the following formula:
Where,
k27 = Coefficient of permeability at 27° C,
k T- Coefficient of permeability at T°C
vT = Coefficient of viscosity at T°C,
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v37 - Coefficient of viscosity at 27 "C.
The void ratio e is evaluated as e = (V*G-W)/Ws the degree of saturations is calculated as.
Experiment No.4
PERMEABILITY BY VARIABLE HEAD
OBJECT:- Study of determination of Coefficient of Permeability by Variable Head Method
[IS: 2720 (part XVII)-1966]
APPARATUS REQUIRED:-
(i) Permeameter Mould: - Non-corrodible material having a capacity of 1000 ml with an
internal diameter of 100 + 0.1 mm and an internal effective height of 127.3 ± 0.1 mm
(Fig.1). The mould is fitted with a detachable base plate and a removable collar
approximately 60 mm high (Fig.2). The internal surface of the mould should be
smooth. (The maximum particle size in the soil to be tested in this mould should be 10
mm. For bigger soil particles a bigger mould is used,
(ii) Compaction Equipment:- (a) For Dynamic Compaction: -50 mm diameter circular
face, weight 2.6 kg and height of fall 310 mm (b) 50 mm diameter circular face,
weight 4.89 kg and height offal! 450 mm
(iii) Drainage Base:- A base with a porous disc, ,12 mm thick having a fitting for
connection to water inlet or outlet (Fig.3). The permeability of the disc should be
more than 10 times the expected permeability of soil. The base should also be
provided with a dummy plate (Fig.4) 12 mm thick and 08 mm in diameter Which to
be used in the place of the porous stone when, the soil specimen is compacted in the
mould
(iv) Drainage Cap:- A cap with an inserted porous disc. 12 mm thick having fitting for
connection to water inlet and outlet (Fig.5). The permeability of the disc should be
more than 10 times the expected permeability of soil. This drainage base and cap
should have finings for being clamped to the Permeameter mould. They should be
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provided with leak-proof seals such as rubber 0-rings or gaskets (Fig.6). The
apparatus should be such that there is no gap between the specimen and the top and
bottom porous discs when it is assembled really for the test.
(v) Constant Head sink: A suitable water reserve is capable of supplying water to the
Permeameter
(vi) Vacuum Pump
(vii) Unfocused Apparatus: -IS Sieves 4.75 mm, mixing pan, graduated cylinder, meter
scale, stop watch, thermometer and de-aired water.
THEORY:- The ease with which water can flow through a saturated soil is known as
permeability. The consolidation process (the rate of settlement of day) depends upon its
permeability. The knowledge of this property is essential in the solution of problems
involving dewatering, yield of water bearing strata, seepage through earth dams, stability of
earthen dams, and embankments as affected by seepage, settlement ale. The quantity of
stored water escaping through and beneath an earthen dam depends upon the permeability of
embankment and foundations respectively present m the voids of a soil mass is called as soil
water or the moisture. Coefficient of permeability or simply permeability is usually evaluated
on the basis of Darcy (aw, which states that the rate of flow through porous medium is
proportional to the hydraulic gradient. For this law to be valid the flow through soil should be
laminar. This method i.e. Constant Head Method is usually used for predominantly sandy
soils.
PREPARATION OF TEST SPECIMEN:-
(a) Disturbed: Sample: -A 2.5 kg sample is taken from a thoroughly mixed air-dried or oven-
dried material. The moisture content is determined (Experiment No.1). The sample is placed
in an airtight container. The desired amount of water (either the CMC or any specified
moisture content) is added to the stored sample and spread evenly over the sample, and after
thorough mixing: the material is again placed in the storage container. The Permeameter
mould is weighed empty to the nearest gram. After greasing lightly the inside of the mould K
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is clamped between the .compaction base plate and extension collar. The assembly is kept on
a solid base.
The dry density for remolded soil sample is either MOD as found from Proctor
Compaction test, field density or any other density at which the test is desired. The amount
of oven-dried soil required car be calculated as W =yd*V (V- volume of the mould, Yd
required density).The amount of water is evaluated by multiplying this with moisture content
(h fraction).The compactive effort may re vary to simulate field conditions. Static
compaction may also be used wherever necessary. For this; attach the 3 cm collar to the
bottom end of the 0.3 liter mould and 2.5 cm collar to it stop end Support the mould assembly
over the 2.5 cm end plug with the 2.5 cm collar resting on the split collar; kept around the 2.5
cm end plug. The 0.3 liter mould should be lightly greased from inside. After completion of
compaction the collar is removed and excess soil is rimmed level with the top of the mould.
The base is detached and the mould full of compacted specimen is weighed. The mould with
the specimen inside is assembled to the drainage base and cap having porous discs as shown
in Fig.6. The porous discs are saturated before assembling trie mould.
(b) Undisturbed Sample:- Undisturbed specimen is trimmed in the form of a cylinder not
larger than about 85 mm in diameter and height equal to that of mould. The specimen is
placed centrally over the porous disc of the drainage case fixed to the mould. The annular
space between the mould and the specimen is filled with ar. impervious material such as
cement slurry or a mixture of 10% powdered Bentor.ile _and SCV = fine sand by weight to
provide sealing between the soil specimen and the round against leakage from the sides.
When using cement slurry the mould is kept on a flat surface other than the porous discs. The
drainage cap is then fixed over the top of the mould.
TEST PROCEDURE:- Saturation: - In the case of soils of medium to high permeability the
specimen is subjected to obtain full saturation. Soils of low permeability require flow.
Under a high head for periods ranging permeability and head. Alternately, in the case of soils
having low increasing vacuum with bottom outlet closed so as to remove air from the soil
voids. The vacuum is increased to at least 70 mm of mercury, which is maintained for 15
minutes or mere depending upon the type of soil. Then a very slow saturation of the specimen
with de-aired water from the bottom upwards under full vacuum is done. When the specimen
is saturated both the top and bottom outlets are dosed.
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Now the specimen is connected through the top Inlet to a selected standpipe. The
bottom outlet is opened and the time interval required for the water level to fall from a known
initial head to a known final head as measured have center of the outlet is recorded. This
stand pipe is refilled water and the test is repeated till three successive observations give the
same time interval the time interval is recorded for the drop in head from the same
initial to final values, as in the first determination. Alternatively, time interval after
selecting the suitable initial and final heads, h1 and h2 respectively, time intervals is noted
for head to fall from tv, h 2) and similarly for (hr h2) ira to h2. The time intervals should be
the same; otherwise the observation should be repeated after refilling the M0 order to
ensure laminar flow condition, Cohesiveness soils are to be tested under a hydraulic
gradient, which may be from 0.2 to 0.3 for loose state of compactness and from 0.3 to 0.5.
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Experiment No.5
PLASTIC LIMIT
OBJECT:- Study of determination of plastic limit of a soil (IS: 2720 (Part V)- 1965)
APPARATUS:-
(i) Porcelain evaporating dish:-A porcelain-evaporating dish of about 12 cm diameters
is used for making the soil paste.
(ii) Spatula:- A flexible spatula with the blade about 8 cm long and 2 cm wide is used
for working with soil.
(iii) Surface for rolling-Ground-glass plate about 20x15 cm is required for rolling
the soil threat.
(iv)Container: Airtight containers to determine the moisture content are required.
(v) Balance - a balance of capacity 200 g and sensitivity of 0.01 g is required to weigh
the soil sample.
(vi)Oven: -Thermostatically controlled with interior of non-corroding material to
maintain the temperature between 1 05C and 11 0 C.
(vii) Rod:- a rod of 3 mm diameter
SOIL SPECIMEN:- A specimen weighing about 20 g from the thoroughly mixed portion of
the material passing 425-micron IS sieve is taken.
THEORY:- Plastic limit (Wp) is the moisture content at which soil changes from plastic to
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semi-solid state. Plastic limit can be defined as minimum water content at which the soil will
just begin crumble when rolled into a thread of approximately 3 mm diameter. Plastic limit
along with liquid limit and related indices is very useful for soil identification. Liquid limits
and plastic limits depend on both the type and amount of clay. Compressibility of soil
increases markedly with increasing plastic limit, whereas strength decreases. On the other
hand, the strength of soil increases with increasing plasticity index. Shearing strength, though
constant al liquid limits, varies at plastic limits for all days. High plastic clay (sometimes
called fat clay) has shearing strength at plastic limit. The shear strength of soil at plastic limit
is about 100 times that at liquid limit i.e. 1.76 kg/cm2.
PROCEDURE:- The following procedure is employed to determine the plastic limit Wp of
the soil sample:
(i) Take about 20 g of air-dried soil passing through 425-micron IS Sieve. Mix it
thoroughly with distilled water in an evaporating dish till the soil mass becomes
plastic enough to be easily moulded with fingers. In case of clayey soils the plastic
soil mass should be left to stand for a sufficient time (24 hours) to allow water to
permeate throughout the soil mass.
(ii) Take about 8 g of this plastic soil, make a ball of it. And roll it on the glass plate with
hand with just sufficient pressure to roll the mass into a thread of uniform diameter
throughout its length. The rate of roiling shall be between 80 and 90 strokes per
minute counting a stroke as one complete motion of the hand forward and back to
starting position again.
(iii) The rolling should be done till the thread diameter is 3 mm. The soil shall then be
needed together to a uniform mass and rolled gain.
(iv) Continue the process until thread just crumbles at 3 mm diameter.
(v) Collect the crumbled soil threads in the airtight container and keep if for water content
determination. The test is repeated twice more. Thus three readings are
obtained for determination.
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TABULATION OF OBSERVATIONS:-
The observations are tabulated as show on next page:
Calculations:- The plastic limit may be calculated as shown in the table
Calculation- The liquid limit of soil which corresponds to the moisture content of a paste
which would give 25 mm penetration of the cone may be determined by following equation:
WL = Wx+ 0.01 (25-x) (wx+l5)
Where, WL == liquid limit of the soil w, moisture content of soil paste
corresponding to penetration of x and
x = depth of penetration of cone in mm.
Report:- The average moisture content in whole number as determined from above equation
is reported as the liquid limit.
Note I:- The above equation is valid only for penetration value between 20 to 30 mm.
Note II:- It is assumed that at liquid limit the shear strength of soil is about 17.6 g/cm2
which the penetrometer gives for a depth of 25 mm under total siding load of 148 g.
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Experiment No.6
SIEVE SIZE ANALYSIS
OBJECT:- Study of Grain Size Analysis by sieving (Dry analysis) [IS: 2720 (part IV) -
1965]
APPARATUS:-
(i) Balance accurate to 0.1% of the weight of sample to be weighed.
(ii) Set of sieves 100 mm to 75-micron.
(iii) Rubber Pestle and mortar.
THEORY:-
In broad sense soils may be divided into two major groups depending upon the
size of particles namely coarse-grained and. fine- grained. When more than the half
material •is retained on 75-micron sieve it is called as coarse-grained soil On the other
hand if more than a half the material passes through the 75-miron sieve it is called as
fine-grained soil. The coarser fractions of soil consist of gravel and sand. Silt and clay
consists the finer fractions of the soil. Anyone grain of this fraction generally consist
of only one mineral. Grain along with the consistency limits is used for soil
classification. The dry or the mechanical analysis is carried out for coarse-grained
soil. Using a set of standard sieves carries out sieve analysis. According standard, the
sieve number is the mesh with expressed in mm or microns.
PROCEDURE:-
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The following procedure can be adopted:
1. Using a riffler, take a representative sample of soil received from the field and dry it in the
oven.
2. Weigh the required quantity of the dry soil. Keep it in a tray and soak it with water [IS:
2720 (part IV)-1965] recommends the following quantities of soil depending the
maximum sieve of soil particles present in the soil mass.
Maximum size of particle present in substantial quantities
(mm)
Weigh of soil to be taken for test
(kg)
63 50
20 6.5
10 1.5
4.75 0.375
3. Puddle the sample thoroughly on the water and transfer the slurry to 4.75 mm sieve. Wash
the slurry with a jet of water. Collect the material retained on 4.75 mm sieve and material
passing through it in a separate container. Keep the material passing retained on 4.75 mm
sieve in the oven.
4. Wash the material through the 4.75 mm sieve through a 15-micron sieve. Collect the
material passing through and retained on 75-micron sieve in separate containers and them
in the oven. The soil passing through the 75-micron sieve is used for sedimentation.
5. Sieve the dried soil retained on 4.75 mm sieve. The following set of sieves is used for
coarse grained soils: IS 63, 20, 10 and 4.75 mm. sieve the dried material retained on 75-
micron sieve. The sieve used for these soils are 21 mm, 600, 425,300, 212, 150 and 75
microns IS sieves. Arranging the various sieves one over the other in the order of their
mesh openings the largest aperture sieve at the bottom, sieving is performed. A receiver is
kept at the bottom and a cover at the top of the whole assembly. The oven-dried sample of
known weight is put on the top sieve, and the whole assembly is fitted oil a sieve-shaking
machine.
6. At least 10 minutes of shaking is desirable for soils with small particles. The portion of
20Civil Engineering Department
Sanghvi Institute Of Management & Science
the soil sample retained on each sieve is weighed. The amount of soil retained on each
sieve is noted carefully. The percentage of soil retained on each sieve is calculated on the
basis of the total mass of soil sample taken and from these results percentage passing
through each sieve is calculated.
Note: If a sizable portion is retained on 75-micron sieve (BS 200 number), it should be
washed. This is done by placing the 75-micron sieve on a pan and pouring clean water. In
this process silt and clay particles sticking to the sand particles are dislodged. Two
grams of sodium hexametaphosphate is added per liter of water used. Washing should
be continued till the water passing 75-micron sieve substantially clean. The fraction
retained on the 75-micron sieve size is dried in the oven. The dried portion is then
received again through 2 mm, l mm, 600, 425, 300, 212, 150 and 75 micron IS sieve.
The portion passing 75-micron while washing is also dried separately and its mass is
determined to get percentage finer than 75-micron.
TABULATION AND OBSERVATION:- The observation are tabulated in the following
tabular form.
S.No.
Sieve size in
mm
Weight retained
in gms % weight retained
% cumulative weight
retained % passing
1 25.4
2 20
3 10
4 4.75
5 2.35
6 1.18
7 0.6
8 0.425
9 0.3
10 0.212
11 0.15
21Civil Engineering Department
Sanghvi Institute Of Management & Science
12 0.075
SANGHVI INSTITUTE OF MANAGEMENT AND SCIENCE
DEPARTMENT OF CIVIL ENGINEERING
LABORATORY MANUAL
OF
GEOTECHNICAL ENGINEERING – I
SUBMITTED TO:- SUBMITTED BY:-
22Civil Engineering Department
Sanghvi Institute Of Management & Science
Mr. Prakash Patidar
(Sr. lecturer)
DEPARTEMENT OF CIVIL ENGINEERING
CONTENTS
Sr.No. NAME OF EXPERIMENT PgNo. REM.
1. Natural and Hygroscopic moisture content 1
2. Liquid Limit By Cassagrande Apparatus 3
3. Permeability By Constant Head 6
4. Permeability By Variable Head 12
5. Plastic Limit 16
6. Sieve Size Analysis 19
23Civil Engineering Department