Question

2. The dry unit weight of a soil is 17.5 kN/m³. Given that G_s = 2.69, and w = 9.8%, determine:

            a. Unit weight

            b. Void ratio

            c. Degree of saturation

Answer 1

The answers are 1) unit weight = 17.92 KN/m3.

2)Void Ratio = 0.507. 3) saturation = 52 % .

Given,

Dry unit weight = 17.5 KN/m3.

Gs = 2.69. , w = 9.8%. = 0.098

As we know,. Dry unit weight = G * w / ( 1 + e )

=> 17.5 = 2.69 * 9.81 / ( 1 + e )

=> e ( void ratio) = 0.507 .

By the relationship,. S * e = w * G

=> S * 0.507 = 0.098 * 2.69

=> S ,( saturation) = 0.5272 = 52 % .

=> Unit weight = ( G + S * e) * w / ( 1 + e)

=> Unit weight = ( 2.69 + 0.52 * 0.507 ) * 9.81 / ( 1 + 0.5 )

=> Unit weight = 17.92 KN/m3.

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