Question

For purely cohesive soil, local shear failure may be assumed to occur when the soil is ___________

(a) Medium to soft

(b) Soft to medium

(c) Hard

(d) All of the mentioned

I had been asked this question at a job interview.

This interesting question is from Terzaghi’s Analysis in division Bearing Capacity of Geotechnical Engineering II

Answer 1

Correct answer is (b) Soft to medium

Best explanation: For purely cohesive soil, local shear failure may be assumed to occur when the soil is soft to medium, with an unconfined compressive strength qu ≤ 100 kN/m^2.