The degree of saturation is defined as the ratio of the volume of water in the soil to the volume of voids. It is denoted by ‘S’.

Where,

S = Degree of saturation

V_{v}= Volume of void

Wc = water content

G_{s} = Specific gravity

e = Void ratio

The degree of saturation is generally expressed in percentage. Its value is equal to 0 when the soil is dry and, its value is 100% when the soil is fully saturated.

## Why degree of saturation is necessary to calculate?

The degree of saturation is necessary to calculate due to the following reason.

1) It helps to know the moisture content in the soil.

2) It helps to identify the dry density of the soil.

3) It helps to identify the required compaction rate of the soil for road construction. etc.

## How to calculate degree of saturation?

**Q) The moist unit weight of a soil is 17.5 KN/M3, given that the water content is 16% and the specific gravity of 2.75. Find the degree of saturation.**

Solution;

Given that,

Water content (w) = 16% = 0.16

Specific gravity (G_{s}) = 2.75

Degree of saturation (S) = ?

We know that,

**Q ) An undisturbed sample of a clayey soil is found to have a wet weight of 300N, a dry weight of 260N, and a total volume of 0.015m3. Suppose the specific gravity of soil solid is 2.70. Find the water content, void ratio, and degree of saturation.**

Solution;

W_{wet}= 300N

W_{dry}= 260N

V_{T}= 0.015 m^{3}

Gs = 2.70

% w =?

e = ?

S=?

We know that;

Water content,

Degree of saturation,

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