Earth Retaining Structures MCQ with answer and solution

Concept

Applicability conditions of Coulomb earth pressure theory

Formula

NONE

Step-by-step solution

1. Coulomb’s earth pressure theory considers the soil mass as a wedge bounded by the wall face and a planar slip surface. 2. Unlike Rankine’s theory which assumes smooth, vertical walls and homogeneous soil, Coulomb’s method accounts for wall friction and non-homogeneous backfill soils. 3. Therefore, Coulomb's earth pressure theory is applicable for non-homogeneous soils as well. Answer: B

Explanation

Coulomb's earth pressure theory considers the limit equilibrium of a sliding soil wedge behind a retaining wall and accounts for wall friction and inclined backfills. Because it uses wedge stability analysis, it can be readily adapted for non-homogeneous and stratified soil layers. This makes it applicable to non-homogeneous soils as well as uniform soil profiles.

Why the other options are wrong

A) Coulomb's theory is also applicable to non-homogeneous backfills. C) Coulomb's theory accounts for wall friction, making it suitable for rough retaining walls as well. D) Option B is correct.

Shortcut

Coulomb's theory applies to both homogeneous and non-homogeneous soils.

Common mistake

Assuming Coulomb's theory applies only to homogeneous soils, confusing its assumptions with Rankine's theory.