Question

In active state, the failure wedge shows ____________

(a) downward movement

(b) upward movement

(c) left side movement

(d) right side movement

This question was posed to me in quiz.

This is a very interesting question from Earth Pressure Introduction in portion Failure Envelopes & Earth Pressure of Geotechnical Engineering II

Answer 1

Right answer is (a) downward movement

To explain: In the active state of plastic equilibrium, the wall moves away from the fill because of the mobilization of the internal resistance of the soil taking place in the direction away from the wall. Due to this the failure wedge shows downward movement.