Question

A rigid retaining wall of 6 m height has a saturated backfill of soft clay soil. What is the critical height when the properties of the clay soil are ${\gamma }_{sat}=17.56kN/m^3$ and cohesion $c=18kN/m^2$

• A. 1. 1 m
• B. 2.1 m
• C. 3.1 m
• D. 4.1 m

Answer 1

The correct option is D 4.1 m


Critical height of unsupported cut
$H_c=\frac{4c}{\gamma \sqrt{k_a}}{k}_a=\frac{1-\sin 0^{\circ }}{1+\sin 0^{\circ }}=1H_c=\frac{4c}{\gamma }=\frac{4\times 18}{17.56}=4.1m$