GATE Civil Engineering (CE) 2015 Shift 2 Solved Paper

A 6 m high retaining wall having a smooth vertical back face retains a layered horizontal backfill. Top 3 m thick layer of the backfill is sand having an angle of internal friction, ϕ = 30° while the bottom layer is 3 m thick clay with cohesion, C = 20 kPa. Assume unit weight for both sand and clay as 18 kN/m³. The total active earth pressure per unit length of the wall (in kN/m) is: