Bearing Capacity of Soil MCQ with answer and solution

Concept

Terzaghies ultimate bearing capacity for strip footings

Formula

q_u = c × N_c + q × N_q + 0.5 × γ × B × N_gamma

Step-by-step solution

1. Terzaghi proposed the general bearing capacity equation for continuous strip footings under general shear failure. 2. The ultimate bearing capacity comprises three distinct resistance terms: cohesion, surcharge, and soil self-weight. 3. The equation is expressed as: qu = c·Nc + q·Nq + 0.5·γ·B·N_gamma. 4. Shape factors 1.3 and 0.4 apply to square footings; 1.3 and 0.3 apply to circular footings. Answer: A

Explanation

According to Terzaghi's bearing capacity theory for general shear failure of a continuous strip footing, the ultimate bearing capacity (qu) is expressed as the sum of cohesion, surcharge, and soil weight terms: qu = c·Nc + q·Nq + 0.5·γ·B·N_gamma.

Why the other options are wrong

B) Formula for square footings: 1.3·c·Nc + q·Nq + 0.4·γ·B·N_gamma. C) Omits the dimensionless bearing capacity factor N_gamma. D) Formula for circular footings: 1.3·c·Nc + q·Nq + 0.3·γ·B·N_gamma.

Shortcut

Strip footing: qu = c·Nc + q·Nq + 0.5·γ·B·N_gamma (no shape coefficients 1.3 or 0.4).

Common mistake

Applying circular/square footing shape factors (1.3 or 0.4) to a continuous strip footing.