Correct Answer - Option 2 : equal to specific gravity of soil
Concept:
Voids ratio:
It is defined as the ratio of total volume of voids to the volume of solids in given soil mass.
\({\rm{e}} = \frac{{{{\rm{V}}_{\rm{v}}}}}{{{{\rm{V}}_{\rm{s}}}{\rm{\;}}}}\)
e > 0, voids ratio has no upper limit
Water content (W):
Water content also called as moisture content is defined as the ratio of weight of water to the weight of soil solids in the soil mass
\({\rm{W}} = \frac{{{{\rm{W}}_{\rm{w}}}}}{{{{\rm{W}}_{\rm{s}}}}} × 100\)\({\rm{W}} = \frac{{{{\rm{W}}_{\rm{w}}}}}{{{{\rm{W}}_{\rm{s}}}}} × 100\)
For dy soils, W = 0
For moist soils it is around, W = 60 %
For a Saturated soils, W > 0
Degree of Saturation (S):
Degree of saturation of a soil is defined as the ratio of volume of water to the volume of voids in the soil mass
\({\rm{S}} = \frac{{{{\rm{V}}_{\rm{w}}}}}{{{{\rm{V}}_{\rm{v}}}}} × 100\)
For dy soils, S = 0
For a Saturated soils, S = 100 %
For partially saturated soils it ranges as 0 % ≤ S ≥ 100 %
The relation between the degree of saturation (S), voids ratio (e), moisture content (W), and specific gravity (G) is given by,
e × S = W × G
Calculation:
Given W% = 100%,
For fully saturated soil mass, we know that
S = 100%
e × s= w × G
In this case, 1 × e = 1 × G
e = G
Hence void ratio is equal to the specific gravity of the soil.
