Question

The Boussinesq influence factor for uniformly distributed circular area is given by ____________

(a) \(K_B= \left[1-\left[\frac{1}{1+(\frac{a}{z})^2}\right]^{\frac{3}{2}}\right] \)

(b) \(K_B= \left[1+\left[\frac{1}{1+(\frac{a}{z})^2}\right]^{\frac{3}{2}}\right] \)

(c) \(K_B= \left[\frac{1}{1+(\frac{a}{z})^2}\right]^{\frac{3}{2}} \)

(d) \(K_B= q\left[1-\left[\frac{1}{1+(\frac{a}{z})^2}\right]^{\frac{5}{2}}\right] \)

This question was posed to me in final exam.

My enquiry is from Stress Distribution topic in section Stress Distribution of Geotechnical Engineering I

Answer 1

The correct option is (a) \(K_B= \left[1-\left[\frac{1}{1+(\frac{a}{z})^2}\right]^{\frac{3}{2}}\right] \)

Easiest explanation: The Boussinesq influence factor for uniformly distributed circular area is given by,

\(K_B= \left[1-\left[\frac{1}{1+(\frac{a}{z})^2}\right]^{\frac{3}{2}}\right] \)

where the KB= Boussinesq influence factor which is a function of r/z ratio which is a dimensionless factor.