GATE Exam Questions - Engineering

Q1:

The total active thrust on a vertical wall 3m high retaining a horizontal sand backfill (unit weight γt = 20 kN/m3, angle of shearing resistance φ' = 30°) when the water table is at the bottom of the wall, will be:

A 30 kN/m

B 35 kN/m

C 4 kN/m

D 45 kN/m

ANS:A - 30 kN/m

Active thrust = 1/2(ka*H^2*yt).

Ka = 1-sin30/1+sin30 = 0.333.

= 1/2(0.333*3^2*20).

= 30 kN/m.