Correct Answer - Option 3 : 200 kPa
Concept:
As per Terzaghi’s theory, The ultimate bearing capacity of square footing is given by,
Ultimate bearing capacity (qu) = 1.3× c× Nc + q × Nq + 0.4 × γ × B × Nγ ....(1)
C - Cohesion of clay
Nc, Nq, Nγ - Bearing capacity factors, γ = unit weight of soil
q = overburden pressure = γ × D
D = depth of the footing, B = width of square footing
Calculation:
Given:
c = 27 kPa, Size of footing = 4 m × 4 m
For saturated clay ϕ = 0°
For ϕ = 0°, Nc = 5.7, Nq = 1, Nγ =0
∴ qu = 1.3 × 27 × 5.7 + γ × D × 1
It is given that the footing rests on soil, D = 0
∴ qu = 1.3 × 27 × 5.7 = 200 kPa.