The dry unit weight of a sandy soil in its natural condition is 16 kN/m3. The minimum and maximum dry unit weights of the same soil are found to be 12 kN/m3 and 20 kN/m3, respectively. What is the Density Index of the soil?

A rigid retaining wall 5 m high is restrained from yielding. The backfill consists of cohesionless soil having φ' = 30° and unit weight of soil γ = 18 kN/m3. Compute the total earth pressure per metre length of the wall at rest. (Consider sin(30°) = 0.5, cos(30°) = 0.866)

Calculate the average contact pressure (in kN/m2) directly beneath a square footing of dimensions 4 m × 4 m carrying a vertical load of 200 kN.