Question

Which of the following is a basic assumption of the wedge theory?

(a) The slip surface is plane

(b) The backfill is dry

(c) The backfill is homogeneous

(d) All of the mentioned

This question was posed to me in a job interview.

The question is from Coulomb’s Wedge Theory topic in chapter Failure Envelopes & Earth Pressure of Geotechnical Engineering II

Answer 1

The correct choice is (d) All of the mentioned

To explain I would say: Based on the assumptions of the wedge theory:

i. The backfill is dry, cohesion less, homogeneous, isotropic, and elastically undeformable.

ii. The slip surface is a plane which passes through the heel of the wall

iii. The sliding wedge itself acts as a rigid body.