5. An undisturbed soil sample has a wet density of 2.5 Mg/m3 when the water content is 25%. The specific gravity of the soil particles is 2.7. Determine the submerged effective density.

The submerged effective density is 86.93 kN/m³ or 8.693 Mg/m³

Explanation:

Given;

wet density of soil sample = 2.5 Mg/m³ = 25 kN/m³

Specific gravity of solid particle = 2.7

The dry unit weight of soil;

for undisturbed state, the volume of the soil is;

Submerged effective density is given as;

density of water (ρw) = 2.7 x 25 kN/m³ = 67.5 kN/m³, substitute this in the above equation;

Therefore, the submerged effective density is 86.93 kN/m³ or 8.693 Mg/m³