Shallow Foundations MCQ with answer and solution

Concept

Terzaghi calls a foundation shallow when its depth is equal to or less than its width (D_f ≤ B).

Formula

D_f/B ≤ 1

Step-by-step solution

1. Terzaghi's bearing capacity theory is for shallow footings. 2. He defines a shallow footing as one with depth D_f ≤ width B. 3. So depth equal to or less than width is the answer. Option A.

Explanation

Terzaghi says a foundation is shallow if its depth is not more than its width. In this case the shear resistance of the soil above the base is neglected and only surcharge is taken. Deeper footings are treated as deep foundations.

Why the other options are wrong

B: depth = 2 × width is deeper than Terzaghi's limit. C: width = 3 × depth is a shallow case, but it is not the definition. D: width = depth/4 means depth = 4 × width, which is a deep foundation.

Shortcut

Terzaghi shallow: D_f ≤ B.

Common mistake

Mixing it up with other limits like D_f/B < 4 or 5 given by some later authors.