Question

During the active state of plastic equilibrium, the retaining wall moves _______

(a) towards the fill

(b) away from the fill

(c) does not change its position

(d) remains in equilibrium

I have been asked this question in an internship interview.

I want to ask this question from Earth Pressure Introduction topic in chapter Failure Envelopes & Earth Pressure of Geotechnical Engineering II

Answer 1

The correct choice is (b) away from the fill

The explanation is: During the active state of plastic equilibrium, the major principal stress denoted by σ1 is in vertical direction and the minor principal stress σ3  is in horizontal direction. Therefore, the movement of the wall will be away from the back fill.