Question

In active state of plastic equilibrium, the earth pressure on the wall ________

(a) increases

(b) decreases

(c) is zero

(d) is constant

I had been asked this question during an internship interview.

The query is from Earth Pressure Introduction topic in division Failure Envelopes & Earth Pressure of Geotechnical Engineering II

Answer 1

Right answer is (b) decreases

The explanation: When the wall moves away from the backfill, mobilization of the internal resistance of the soil takes place in the direction away from the wall. Hence the earth pressure on the wall decreases.