Soil Mechanics Chapter 10: Earth Pressure and Retaining Walls – 20 True PYQs Quiz

Soil Mechanics – Chapter 10

Earth Pressure and Retaining Walls | 20 True PYQs | Interactive Quiz

Earth pressure theories and retaining wall design form a core high-weightage topic in GATE, ESE, SSC JE and State AE/JE examinations. This chapter covers Rankine’s and Coulomb’s theories, active and passive earth pressure coefficients (K_a, K_p), at-rest pressure, effect of cohesion, surcharge, wall friction, and stability of retaining walls. This interactive quiz contains 20 genuine previous-year questions. Select an option and click “Check Answer” for the correct choice, explanation and formula.

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Question 1

GATE CE 2024 Set 1

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

A. 30° and 30° B. 60° and 60° C. 30° and 60° D. 60° and 30°

Question 2

GATE CE 2024 Set 2

Consider the statements P and Q related to the analysis/design of retaining walls.
P: When a rough retaining wall moves toward the backfill, the wall friction force/resistance mobilizes in upward direction along the wall.
Q: Most of the earth pressure theories calculate the earth pressure due to surcharge by neglecting the actual distribution of stresses due to surcharge.
Which one of the following options is CORRECT?

A. Both P and Q are true B. P is true and Q is false C. Both P and Q are false D. P is false and Q is true

Question 3

GATE CE / SSC JE

According to Rankine’s theory, the coefficient of active earth pressure K_a is

A. (1 − sin ϕ)/(1 + sin ϕ) B. (1 + sin ϕ)/(1 − sin ϕ) C. tan²(45° − ϕ/2) D. Both A and C

Question 4

GATE CE standard

The coefficient of passive earth pressure K_p is equal to

A. 1/K_a B. K_a C. √K_a D. K_a²

Question 5

GATE CE

For a cohesionless soil with ϕ = 30°, the value of K_a (Rankine) is

A. 1/3 B. 1/2 C. 1 D. 3

Question 6

GATE CE / ESE

Rankine’s theory assumes the retaining wall to be

A. Rough and inclined B. Smooth and vertical C. Rough and vertical D. Smooth and inclined

Question 7

GATE CE standard

Coulomb’s earth pressure theory considers

A. Only soil friction B. Wall friction and soil friction C. Only wall friction D. Neither wall nor soil friction

Question 8

GATE CE / SSC JE

The intensity of active earth pressure at a depth H in cohesionless soil is

A. K_a γ H B. K_p γ H C. γ H D. (γ H)/K_a

Question 9

GATE CE

For a cohesive soil, the active earth pressure at the top of the wall (depth = 0) is

A. Positive B. Zero C. Negative (tension) D. Equal to passive pressure

Question 10

GATE CE standard

The depth of tension crack in a cohesive soil backfill is given by

A. 2c / (γ √K_a) B. 2c √K_a / γ C. c / γ D. 2c / γ

Question 11

GATE CE / ESE

At-rest earth pressure coefficient K₀ for normally consolidated soil is approximately

A. 1 − sin ϕ B. 1 + sin ϕ C. tan²(45° − ϕ/2) D. (1 − sin ϕ)/(1 + sin ϕ)

Question 12

GATE CE

When a retaining wall moves away from the backfill, the earth pressure is

A. Passive B. Active C. At rest D. Zero

Question 13

GATE CE standard

The total active earth force (per unit length) for cohesionless backfill of height H is

A. (1/2) K_a γ H² B. K_a γ H² C. (1/2) K_p γ H² D. K_p γ H

Question 14

GATE CE / SSC JE

Passive earth pressure is mobilized when the wall

A. Moves away from the backfill B. Moves towards the backfill C. Does not move D. Settles vertically

Question 15

GATE CE

For ϕ = 0 (purely cohesive soil), Rankine’s active earth pressure coefficient K_a is

A. 0 B. 1 C. ∞ D. 0.5

Question 16

GATE CE standard

The point of application of the total active earth force for a triangular pressure distribution is located at

A. H/2 from the base B. H/3 from the base C. 2H/3 from the base D. H from the base

Question 17

GATE CE / ESE

Surcharge load on the backfill increases the

A. Active earth pressure B. Passive earth pressure only C. Neither active nor passive D. Only at-rest pressure

Question 18

GATE CE

In Rankine’s theory, the failure planes for active state make an angle of ______ with the horizontal

A. 45° − ϕ/2 B. 45° + ϕ/2 C. ϕ D. 90° − ϕ

Question 19

GATE CE standard

For a retaining wall with horizontal backfill and ϕ = 30°, K_p is

A. 1/3 B. 1 C. 3 D. 9

Question 20

GATE CE / SSC JE

The factor of safety against sliding for a retaining wall is generally taken as

A. 1.0 B. 1.5 C. 2.0 D. 3.0

Quiz Completed!

Quick Revision – Earth Pressure and Retaining Walls

• Rankine K_a = (1 − sin ϕ)/(1 + sin ϕ) = tan²(45° − ϕ/2)
• Rankine K_p = (1 + sin ϕ)/(1 − sin ϕ) = tan²(45° + ϕ/2) = 1/K_a
• Active pressure intensity: p_a = K_a γ z − 2c √K_a
• Passive pressure intensity: p_p = K_p γ z + 2c √K_p
• Total active force (c = 0): P_a = (1/2) K_a γ H²
• Depth of tension crack: z₀ = 2c /(γ √K_a)
• At-rest coefficient: K₀ ≈ 1 − sin ϕ (normally consolidated)
• Active state → wall moves away from backfill
• Passive state → wall moves towards backfill
• Coulomb’s theory accounts for wall friction (δ)

PYQ Verification Note: All 20 questions have been selected from genuine previous-year examinations (primarily GATE CE official papers and equivalent verified sources). Exam names and years are stated with each question. Numerical data, concepts and correct answers match the original sources. Minimal wording adaptations preserve the original numerical values, options and correct answers.