At a lake location, the soil surface is 6 m under the water surface. Samples from the soil deposit underlying the lake indicate a wet unit weight of 18.8 kN/m3. Determine the effective and total vertical stresses in the deposit at a depth of 12 m below the soil surface.

The effective stress is 225.6 kN/m²

The total vertical stress is 338.4 kN/m²

Explanation:

Given;

depth of soil surface = 6m

weight unit of the soil samples = 18.8 kN/m³

Stress = force/area

Stress = unit weight x depth

Effective stress at a depth of 12 m below the soil surface:

= (18.8 kN/m³) x (12 m)

= 225.6 kN/m²

Effective stress = 225.6 kN/m²

Total vertical stress at a depth of 12 m below the soil surface:

= (18.8 kN/m³) x (6 m) + (18.8 kN/m³) x (12 m)

= 112.8 kN/m² + 225.6 kN/m²

= 338.4 kN/m²

Total vertical stress = 338.4 kN/m²