Question

What will be the intensity of vertical stress at a depth of 4m directly below the concentrated load of 20 kN?

(a) 0.4356 kN/m^2

(b) 0.244 kN/m^2

(c) 0.652 kN/m^2

(d) 0.597 kN/m^2

I got this question in final exam.

I want to ask this question from Stress Distribution topic in section Stress Distribution of Geotechnical Engineering I

Answer 1

The correct option is (d) 0.597 kN/m^2

To explain: Given,

Z=4m

Q=20 kN

r=0

The Boussinesq’s vertical stress σz is given by,

\(σ_z=\frac{3Q}{2πz^2}\left[\frac{1}{1+(\frac{r}{z})^2}\right]^{\frac{5}{2}}\)

∴ \(σ_z=\frac{3*20}{2π4^2}\)

∴ σz=0.597 kN/m^2.