Bearing Capacity of Soil MCQ with answer and solution

Concept

Allowable Bearing Capacity

Formula

q_allowable = Min(q_netsafe, q_{safebearingpressure})

Step-by-step solution

1. Identify the given values: Net safe bearing capacity = 350 kPa and Safe bearing pressure = 400 kPa. 2. Apply the formula: Allowable bearing capacity = Min(350, 400). 3. Compare the values and select the smaller one: 350 kPa (Option B).

Explanation

The allowable bearing capacity is the maximum pressure a soil can safely support without experiencing shear failure or excessive settlement. When designing a footing, the allowable bearing capacity is taken as the smaller (more critical) value between the net safe bearing capacity (which prevents shear failure) and the safe bearing pressure (which prevents excessive settlement). Comparing 350 kPa and 400 kPa, the smaller value is 350 kPa.

Shortcut

Allowable bearing capacity is always the smaller (minimum) value between net safe bearing capacity and safe bearing pressure.

Common mistake

Students often select the larger value (400 kPa) instead of taking the minimum of the net safe bearing capacity and safe bearing pressure.