SOIL COMPOSITION

-Ms IkmalzatulCE1303 – Engineering Material Properties

CE 1203 : Geotechnical Properties and Construction Methods

The nature of Soil

Soil is defined as a collection of mineral particles that was formed due to the weathering process of igneous rock and mixed with organic matter.

The void between particles is filled with water and gas. Cementation among the particles is weak and is due to

carbonation and oxidation between particles and or organic matter.

Characteristics of soil in general are greatly influenced by the process of the soil formation.

The structural arrangement of the particle may be loose, medium dense or dense depending on the packing of material.

CE 1203 : Geotechnical Properties and Construction Methods

Soil: A 3-Phase Material

Solid

WaterAir

CE 1203 : Geotechnical Properties and Construction Methods

The Mineral Skeleton

Volume

Solid Particles

Voids (air or water)

CE 1203 : Geotechnical Properties and Construction Methods

Three Phase Diagram

Solid

Air

Water

Mineral Skeleton Idealization:Three Phase Diagram

CE 1203 : Geotechnical Properties and Construction Methods

Fully Saturated Soils

Fully Saturated

Water

Solid

Mineral Skeleton

CE 1203 : Geotechnical Properties and Construction Methods

Dry Soils

Mineral Skeleton Dry Soil

Air

Solid

CE 1203 : Geotechnical Properties and Construction Methods

Partly Saturated Soils

Solid

Air

Water

Mineral Skeleton Partly Saturated Soils

CE 1203 : Geotechnical Properties and Construction Methods

Three Phase System

Volume Weight

Solid

Air

WaterWT

Ws

Ww

Wa~0

Vs

Va

Vw

Vv

VT

CE 1203 : Geotechnical Properties and Construction Methods

Weight Relationships

Weight Components: Weight of Solids = Ws

Weight of Water = Ww

Weight of Air ~ 0

%100(%), s

w

W

WwContentWater

CE 1203 : Geotechnical Properties and Construction Methods

Volumetric Relationships

Volume Components: Volume of Solids = Vs

Volume of Water = Vw

Volume of Air = Va

Volume of Voids = Va + Vw = Vv

s

v

V

VeRatioVoid ,

%100(%), T

v

V

VnPorosity

CE 1203 : Geotechnical Properties and Construction Methods

Volumetric Relationships

Volume Components: Volume of Solids = Vs

Volume of Water = Vw

Volume of Air = Va

Volume of Voids = Va + Vw = Vv

%100(%), V

w

V

VSSaturationofDegree

CE 1203 : Geotechnical Properties and Construction Methods

Specific Gravity

Unit weight of Water, w w = 1.0 g/cm3 (strictly accurate at 4° C)

w = 62.4 pcf

w = 9.81 kN/m3

WaterofVolumeEqualanofWeight

ceSubsaofWeightGravitySpecific

tan

WaterofWeightUnit

ceSubsaofWeightUnitGravitySpecific

tan

CE 1203 : Geotechnical Properties and Construction Methods

Specific Gravity Iron 7.86 Aluminum 2.55-2.80 Lead 11.34 Mercury 13.55

Granite 2.69 Marble 2.69 Quartz 2.60 Feldspar 2.54-2.62

CE 1203 : Geotechnical Properties and Construction Methods

Specific Gravity, Gs

CE 1203 : Geotechnical Properties and Construction Methods

Soil Unit weight (kN/m3)

Bulk (or Total) Unit weight = WT / VT

Dry unit weightd = Ws / VT

Buoyant (submerged) unit weightb = - w

CE 1203 : Geotechnical Properties and Construction Methods

Typical Unit weights

CE 1203 : Geotechnical Properties and Construction Methods

Example: Volumetric Ratios

Determine void ratio, porosity and degree of saturation of a soil core sample

Data: Weight of soil sample = 1013g Vol. of soil sample = 585.0cm3

Specific Gravity, Gs = 2.65 Dry weight of soil = 904.0g

CE 1203 : Geotechnical Properties and Construction Methods

Solid

Air

Water

Wa~0

Volumes Weights

1013.0g585.0cm3

904.0g

s =2.65

109.0g

341.1cm3

109.0cm3

243.9cm3

134.9cm3

W =1.00

Example

CE 1203 : Geotechnical Properties and Construction Methods

585.0cm3

Solid

Air

Water

Volumes

s =2.65341.1cm3

109.0cm3

243.9cm3

134.9cm3

W =1.00

%7.441009.243

0.109%100(%)

%7.411000.585

9.243%100(%)

72.01.341

9.243

v

w

T

v

s

v

V

VS

V

Vn

V

Ve

Example

THE END