Question

What will be the intensity of shear stress at a depth of 4m and at a radial distance of 1m from concentrated load of 20 kN?

(a) 0.4356 kN/m^2

(b) 0.244 kN/m^2

(c) 0.652 kN/m^2

(d) 0.128 kN/m^2

I had been asked this question by my college director while I was bunking the class.

This interesting question is from Stress Distribution in section Stress Distribution of Geotechnical Engineering I

Answer 1

The correct choice is (d) 0.128 kN/m^2

Easy explanation: Given,

Z=4m

Q=20 kN

r=1

The Boussinesq’s shear stress τrz is given by,

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

∴ \(τ_{rz}=\frac{3*20*1}{2π4^3}\left[\frac{1}{1+(\frac{1}{4})^2}\right]^{\frac{5}{2}} \)

∴ τrz=0.128 kN/m^2.