basis physical property
01/03/2012
SOIL COMPOSITION
SOIL COMPOSITION
Generally soil can be divided to three components in natural occurrence
This separation know as three phase systems or three phase diagram
It consists of soil solids, water and air
1
01/03/2012
Soil components in natural occurrence
Volume-Weight relationships
As a result from 3 phase diagram several relationship were produce
This relationship known as volume weight relationships. Refer to 3 phase diagram
2
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Relationship equations
V = Vs +Vv
( eq. 1)
= Vs + Vw + Va where Vs = volume of soil solids
Vv = volume of voids
Vw = volume of water in the voids Va = volume of air in voids
3
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Relationship equations
W = Ws + Ww where, Ws =
Ww=
Wa =
( eq. 2)
weight of soil solid weight of water zero (negligible)
Water content@ Moisture content
4
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Void ratio
The ratio of the volume of voids Vv to the volume of soil solid Vs
Porosity
The ratio of the volume of voids, Vv to total volume, V expressed as either a decimal or a percentage. 5
01/03/2012
Relationship between void ratio and porosity e = Vv = Vv
= (Vv/V ) = n
Vs
V – Vv 1 – (Vv/V)
1- n
n=
e
1+e
Degree of saturation
The ratio of the volume of water, Vw to the volume of voids, Vv. It’s commonly in percentage
6
01/03/2012
Unit weight
The weight of soil per unit volume
Moist unit weight
Dry unit weight
Relationship between dry unit and bulk unit weight
7
01/03/2012
Derivation –cont’d
So what is the different between unit weight and density? Unit Weight is influence by gravity forces while mass isn’t (Unit Weight=Weight/ Volume while Density=
Mass/Volume)- Weight = Mass x Gravity acceleration
So we can use the similar equations on related calculation if there is only density
Specific Gravity
Specific gravity can be determined as a ratio of the unit weight of the soil material to the
SOIL COMPOSITION
SOIL COMPOSITION
Generally soil can be divided to three components in natural occurrence
This separation know as three phase systems or three phase diagram
It consists of soil solids, water and air
1
01/03/2012
Soil components in natural occurrence
Volume-Weight relationships
As a result from 3 phase diagram several relationship were produce
This relationship known as volume weight relationships. Refer to 3 phase diagram
2
01/03/2012
Relationship equations
V = Vs +Vv
( eq. 1)
= Vs + Vw + Va where Vs = volume of soil solids
Vv = volume of voids
Vw = volume of water in the voids Va = volume of air in voids
3
01/03/2012
Relationship equations
W = Ws + Ww where, Ws =
Ww=
Wa =
( eq. 2)
weight of soil solid weight of water zero (negligible)
Water content@ Moisture content
4
01/03/2012
Void ratio
The ratio of the volume of voids Vv to the volume of soil solid Vs
Porosity
The ratio of the volume of voids, Vv to total volume, V expressed as either a decimal or a percentage. 5
01/03/2012
Relationship between void ratio and porosity e = Vv = Vv
= (Vv/V ) = n
Vs
V – Vv 1 – (Vv/V)
1- n
n=
e
1+e
Degree of saturation
The ratio of the volume of water, Vw to the volume of voids, Vv. It’s commonly in percentage
6
01/03/2012
Unit weight
The weight of soil per unit volume
Moist unit weight
Dry unit weight
Relationship between dry unit and bulk unit weight
7
01/03/2012
Derivation –cont’d
So what is the different between unit weight and density? Unit Weight is influence by gravity forces while mass isn’t (Unit Weight=Weight/ Volume while Density=
Mass/Volume)- Weight = Mass x Gravity acceleration
So we can use the similar equations on related calculation if there is only density
Specific Gravity
Specific gravity can be determined as a ratio of the unit weight of the soil material to the