The GATE Grind

GATE 2024 CE (CE1) – Question 41

Geotechnical Engineering · Earth pressure theories: Rankine and Coulomb, sheet piles · 2 marks · Multiple choice

A vertical smooth rigid retaining wall is supporting horizontal ground with dry cohesionless backfill having a friction angle of 30°. The inclinations of failure planes with respect to the major principal plane for Rankine's active and passive earth pressure conditions, respectively, are

  1. 30° and 30°
  2. 60° and 60°
  3. 30° and 60°
  4. 60° and 30°

Practise this question in The GATE Grind →

Show answer and explanation

Correct answer: (D) 60° and 30°

Explanation

In Rankine's theory the failure planes make the angle $45° + \frac{\phi}{2}$ with the major principal plane in the active state, and $45° - \frac{\phi}{2}$ in the passive state. With $\phi = 30°$ these are 60° and 30°.