Question

For an angle of internal friction of 300, the values of coefficients of active and passive earth pressures are given by a _____ and ____ respectively.

(a) \(\frac{1}{3}\), 3

(b) \(\frac{1}{5}\), 5

(c) 3, \(\frac{1}{3}\)

(d) 5, \(\frac{1}{5}\)

I got this question during an internship interview.

My question is from Earth Pressure Problems in portion Failure Envelopes & Earth Pressure of Geotechnical Engineering II

Answer 1

Correct option is (a) \(\frac{1}{3}\), 3

The explanation: Given,

Φ=300,

Therefore \(K_a=\frac{1-sin⁡φ}{1+sin⁡φ}=\frac{1+sin⁡30}{1+sin⁡30}=\frac{1}{3}\)

\(K_p=\frac{1}{K_a} =3.\)