Question

For a soil deposit, C=20 KN/m^2 and is found be to a purely cohesive soil. It has a critical height of an unsupported vertical cut as 4m. Find the unit weight of soil.

(a) 13 kN/m^3

(b) 20 kN/m^3

(c) 56 kN/m^3

(d) 77 kN/m^3

This question was posed to me during an online interview.

My doubt stems from Earth Pressure Problems topic in portion Failure Envelopes & Earth Pressure of Geotechnical Engineering II

Answer 1

Correct answer is (b) 20 kN/m^3

Explanation: Given,

C= 20 kN/m^2

Φ=0,this makes tan⁡∝=1

Hc= 4 m

Therefore \(H_c=\frac{4c}{γ}  tan⁡∝\)

γ = 4×\(\frac{20}{4}×1\)= 20 kN/m^3.