Question

If the load is at the surface of subgrade, the Boussinesq settlement factor is given by ________

(a) 1.5

(b) 2

(c) 2.5

(d) 3

I got this question in unit test.

I want to ask this question from Stresses in Flexible Pavements topic in portion Design of Flexible & Rigid Pavement of Geotechnical Engineering II

Answer 1

Right option is (a) 1.5

Explanation: When the load is at the surface of subgrade, z=0,

∴ \(F_B=\frac{3}{2}\frac{1}{(1+(\frac{z}{a})^2)^\frac{1}{2}} =\frac{3}{2}\frac{1}{(1+(\frac{0}{a})^2)^\frac{1}{2}} \)

∴ FB=1.5.