Question

If θ is the angle subtended by the edges of the strip load, then the Boussinesq’s vertical pressure σz due to strip load is given by ________

(a) \(σ_z=\frac{q}{π}(θ+sinθ)\)

(b) \(σ_z=\frac{q}{π}(θ-sinθ)\)

(c) \(σ_z=\frac{q}{π}(sinθ)\)

(d) \(σ_z=\frac{q}{π} θ\)

I had been asked this question during an online interview.

This key question is from Stress Distribution in chapter Stress Distribution of Geotechnical Engineering I

Answer 1

Right answer is (a) \(σ_z=\frac{q}{π}(θ+sinθ)\)

To elaborate: The vertical pressure due to elementary line load is given by,

\(∆σ_z=\frac{2q’}{πz}\frac{1}{[1+(\frac{0}{z})^2 ]^2} \)

When θ is the angle subtended by the edges of the strip load, the Boussinesq’s vertical pressure σz due to strip load is given by \(σ_z=\frac{q}{π}(θ+sinθ).\)