Question

For an angle of internal friction of 30°, find the flow value Nφ

(a) 4

(b) 10

(c) 3

(d) 0

This question was posed to me by my school teacher while I was bunking the class.

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

Answer 1

Correct option is (c) 3

To explain: Given,

φ=30°

Therefore flow value \(N_φ=tan^2⁡ (45+\frac{φ}{2})\)

\(N_φ=tan^2⁡(45+\frac{30}{2})\)

Nφ=3.