Question

What will be the dry unit weight (in kN/m³) for a saturated soil, given that moisture content (w) = 35 % and specific gravity of soil (G_s) = 2.5?

1. 13.08 kN/m3
2. 13.58 kN/m3
3. 11.08 kN/m3
4. 10.68 kN/m3

Answer 1

Correct Answer - Option 1 : 13.08 kN/m3

Concept:

Dry unit weight, \({γ _d} = \frac{{G{γ _w}}}{{1 + e}}\)

Se = wG

Where, 

S = saturation

w = water content

G = specific gravity

e = void ratio

Calculation:

Given, 

w = 35 %, G_s = 2.5, γ_w = 9.81 kN/m³

S = 1 as given saturated soil

e = wG = 0.35 × 2.5 = 0.875

\({\gamma _d} = \frac{{2.5 \times 9.81}}{{1 + 0.875}} = 13.08\;kN/{m^3}\)