The degree of saturation of a soil sample is defined as:

Explanation:

Degree of saturation:

\({\bf{S}} = \frac{{{{\bf{V}}_{\bf{w}}}}}{{{{\bf{V}}_{\bf{v}}}}} = \frac{{{\bf{Volume}}{\rm{ }}\ {\bf{of}}{\rm{ }}\ {\bf{water}}}}{{{\bf{Volume\ }}{\rm{ }}{\bf{of}}{\rm{ }}\ {\bf{voids}}}}\)

When soil is perfectly dry,

The Volume of water = 0

Then, the Degree of saturation = 0.

Note:

For fully saturated soil, the Degree of saturation = 1

Because Volume of water = volume of voids