Question

A point load of 700 kN is applied on the surface of thick layer of saturated clay. Using Boussinesq's elastic analysis, the estimated vertical stress $\left({\sigma }_v\right)$ at a depth of 2m and a radial distance of 1.0 m from the point of application of the load is:

• A. 47.5 kPa
• B. 47.6 kPa
• C. 47.7 kPa
• D. 47.8 kPa

Answer 1

The correct option is D 47.8 kPa

Apply Boussinesq's equation.

${\sigma }_v=\frac{3}{2\pi }\frac{Q}{z^2}{\left[\frac{1}{1+{\left(\frac{r}{z}\right)}^2}\right]}^{5/2}$

$=\frac{3}{2\pi }\times \frac{700}{(2{)}^2}{\left[\frac{1}{1+{\left(\frac{1}{2}\right)}^2}\right]}^{5/2}$

$=47.8kN/m^2$