Question

What will be the coefficient of earth pressure at rest for a rigid retaining wall, If the backfill consists of cohesion less soil having φ = 26°?

(a) 0.1295

(b) 0.6552

(c) 0.5616

(d) 0.7383

The question was posed to me in a national level competition.

My doubt stems from Active Earth Pressure: Rankine’s Theory topic in division Failure Envelopes & Earth Pressure of Geotechnical Engineering II

Answer 1

The correct answer is (c) 0.5616

To explain I would say: Coefficient of earth pressure, K0 can be calculated using Jacky’s formula:

Given: φ = 26°

Formula: K0=1 – sin φ

K0 = 1 – sin 26°

K0 = 1 – 0.4383

K0 = 0.561628.