Void ratio:
Void ratio is defined as the ratio of volume of voids to the volume of solid particles i.e,
`e=V_v/V_s`
`or, e=(V_w+V_a)/V_s`
Its value may be less than one, equal to one or greater than one. Generally, its range is form 0.5 to 1.5
Porosity:
Porosity denoted by n, is defined as the ratio of volume of voids to the total volume of soil. It is expressed in percentage.i.e,
`n=V_v/V*100`
`=(V_a+V_w)/(V_a+V_w+V_s)*100`
Degree of saturation:
Degree of saturation denoted by $S_r$ is defined as the ratio of volume of water to the total volume of voids in the soil mass. It is expressed in percentage.i.e,
`S_r=V_w/V_v*100`
For a fully saturated soil mass;
`V_v=V_w`, hence `S=1`.
The submerged soil is fully saturated soils.
For perfectly dry soil mass;
`V_w=0` and hence `S = 0`.
Water content:
Water content or content of a soil mass, denoted by w, is defined as the ratio of we....
Show MoreVoid ratio:
Void ratio is defined as the ratio of volume of voids to the volume of solid particles i.e,
`e=V_v/V_s`
`or, e=(V_w+V_a)/V_s`
Its value may be less than one, equal to one or greater than one. Generally, its range is form 0.5 to 1.5
Porosity:
Porosity denoted by n, is defined as the ratio of volume of voids to the total volume of soil. It is expressed in percentage.i.e,
`n=V_v/V*100`
`=(V_a+V_w)/(V_a+V_w+V_s)*100`
Degree of saturation:
Degree of saturation denoted by $S_r$ is defined as the ratio of volume of water to the total volume of voids in the soil mass. It is expressed in percentage.i.e,
`S_r=V_w/V_v*100`
For a fully saturated soil mass;
`V_v=V_w`, hence `S=1`.
The submerged soil is fully saturated soils.
For perfectly dry soil mass;
`V_w=0` and hence `S = 0`.
Water content:
Water content or content of a soil mass, denoted by w, is defined as the ratio of weight of water to the weight of dry soil. i.e,
`w=W_w/W_s`
The weight used in the about expressions is the weight of water loss when the soil is heated to a temperature of 105 degree centigrade to 110 degree centigrade for such length of time that its weight is constant. In routing laboratory test, a period of 24 hours is considered enough for drying.
Bulk unit weight:
Bulk Unit Weight or mass unit weights denoted by `gamma_t` is defined as the weight of soil mass per unit volume of soil mass.i.e,
`gamma_t=W/V`
=`(W_s+W_w)/(V_s+V_w+V_a)`
Dry unit weight:
Dry Unit Weight denoted by `gamma_s` is defined as the ratio of weight of solid to volume of soil.i.e,
`gamma_s=W_s/V`
Unit weight of water:
It is the ratio of weight of water per unit volume of water.i.e,
`gamma_w=W_w/V_w`
Saturated Density:
When the soil mass is saturated, its bulk density is called the saturated density. Thus saturated density is the ratio of the total weight of a saturated soil sample to its total volume (V).
i.e, `gamma_(s a t)=W_(s a t)/ V`
Submerged Density:
The submerged density or buoyant unit weight is defined as the submerged weight of the soil solids per unit of total volume (V) of the soil mass.
`gamma_(s u b)=((W_s)_(s u b) )/V`
`gamma_(s u b)=gamma_(s a t)-gamma_w`
Density (unit weight) of solids:
The unit weight of soil solids is the weight of soil solids per unit volume of solids (Vs);
i.e, `gamma_s=W_s/V_s`
Specific gravity of solids:
It is the ratio of Unit Weight of soil solid to Unit Weight of water at 4 degree centigrade.i.e,
`G=gamma_s/gamma_w`
`=W_s/(V_s*gamma_w)`
NOTE:
Unless otherwise stated, we shall denote the specific gravity (G) as the specific gravity of soil solids
Specific gravity of water:
It is defined as the ratio of Unit Weight of water at any temperature to Unit Weight of water at 4 degree centigrade.i.e,
`G_t=gamma_w/gamma_0`
Where,`gamma_0` is the Unit Weight of water at 4 degree centigrade.
Percentage of air voids:
It is the ratio of the volume of air volds to the total volume of the soil mass (V) and is expressed as percentage. Mathematically,
`eta_a=V_a/V**100`
Air Content:
It is the ratio of the volume of air voids to the volume of voids.
i.e, `a_c=V_1/V_v`
since `V_a=V_v-V_w`, `a_c=1-V_w/V_v=1-S`
Where S is the degree of saturation.
Density index or relative density or degree of density of soil mass :
It is the ratio of the difference between the volds ratio of the soil in its loosest state (`e_(m a x)`) and natural voids ratio (`e`) to the difference between the voids ratio in the loosest state (`e_(m a x)`) and t densest state (`e_(m i n)`). Mathematically
`I_D=(e_(m a x)-e)/(e_(m a x)-e_(m i n))=(rho_( m a x)(rho-rho_( m a x)))/(rho (rho_( m a x)-rho_( m i n)))`
The value of `I_D` varies from zero to unity.
If `I_D=0` then natural state of soil is in loosest form.
If `I_D=1` then natural state of soil is in densest form
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