Engineering Questions with Answers - Multiple Choice Questions
Earth Pressure Introduction – 2
1 - Question
In active state, the minor principal stress σ3 is _________
a) horizontal direction
b) vertical direction
c) can be both vertical and horizontal direction
d) in no direction
View Answer
Answer: a
Explanation: In active state, the minor principal stress denoted by σ3 is in horizontal direction. While in the passive state, the minor principal stress σ3 is in vertical direction.
2 - Question
In passive state, the major principal stress σ1 ____________
a) horizontal direction
b) vertical direction
c) can be both vertical and horizontal direction
d) in no direction
View Answer
Answer: a
Explanation: In passive state, the minor principal stress denoted by σ3 is in vertical direction. While in the passive state, the major principal stress σ1 is in horizontal direction.
3 - Question
In passive state, the minor principal stress σ3 is _________
a) horizontal direction
b) vertical direction
c) can be both vertical and horizontal direction
d) in no direction
View Answer
Answer: b
Explanation: In active state, the minor principal stress denoted by σ3 is in horizontal direction. While in the passive state, the minor principal stress σ3 is in vertical direction.
4 - Question
For cohesion-less soil, the ratio of major to minor principal stress is __________
a) σ1σ3=cos2(45°+φ2)
b) σ1σ3=sin2(45°+φ2)
c) σ1σ3=tan2(45°+φ2)
d) σ1σ3=tan2(45°−φ2)
View Answer
Answer: c
Explanation: The stress condition during plastic equilibrium is given by,
σ1=2ctan(45°+φ2)+σ3tan2(45°+φ2), and for cohesion-less soil, c=0,
∴ σ1σ3=tan2(45°+φ2).
5 - Question
The ratio of horizontal stress σh to vertical stress σv is _______
a) coefficient of earth pressure
b) coefficient of volume change
c) coefficient of compressibility
d) coefficient of consolidation
View Answer
Answer: a
Explanation: The coefficient of earth pressure is defined as the ratio of The ratio of horizontal stress σh to vertical stress σv.
∴ K=σhσv. Where, K = coefficient of earth pressure.
6 - Question
The coefficient of earth pressure for active state of plastic equilibrium is given by ___________
a) Ka=1tan2(45°+φ2)
b) Ka=tan2(45°+φ2)
c) Ka=sin2(45°+φ2)
d) Ka=1cot2(45°+φ2)
View Answer
Answer: a
Explanation: For the case of active state, the major principal stress denoted by σ1 is in vertical direction and the minor principal stress σ3 is in horizontal direction.
∴ σ1σ3=σvσh=Ka=1tan2(45°+φ2).
7 - Question
The coefficient of earth pressure for passive state of plastic equilibrium is given by ________
a) Kp=1tan2(45°+φ2)
b) Kp=tan2(45°+φ2)
c) Kp=sin2(45°+φ2)
d) Kp=1cot2(45°+φ2)
View Answer
Answer: b
Explanation: For the case of passive state, the major principal stress denoted by σ1 is in horizontal direction and the minor principal stress σ3 is in vertical direction.
∴ σ1σ3=σhσv=Kp=tan2(45°+φ2).
8 - Question
The coefficient of earth pressure for active state of plastic equilibrium in terms of sine function is _______
a) Ka=1−sinφ
b) Ka=1−sinφ1+sinφ
c) Ka=1+sinφ1−sinφ
d) Ka=1+sinφ
View Answer
Answer: b
Explanation: The coefficient of earth pressure for active state of plastic equilibrium is,
Ka=1tan2(45°+φ2),
∴ therefore in terms of sine function,
Ka=1tan2(45°+φ2)=1−sinφ1+sinφ.
9 - Question
The coefficient of earth pressure for passive state of plastic equilibrium in terms of sine function is _______
a) Ka=1−sinφ
b) Ka=1−sinφ1+sinφ
c) Ka=1+sinφ1−sinφ
d) Ka=1+sinφ
View Answer
Answer: c
Explanation: The coefficient of earth pressure for active state of plastic equilibrium is,
Kp=tan2(45°+φ2),
∴ therefore in terms of sine function,
Kp=tan2(45°+φ2)=1+sinφ1−sinφ.
10 - Question
During the active state of plastic equilibrium, the retaining wall moves _______
a) towards the fill
b) away from the fill
c) does not change its position
d) remains in equilibrium
View Answer
Answer: b
Explanation: During the active state of plastic equilibrium, the major principal stress denoted by σ1 is in vertical direction and the minor principal stress σ3 is in horizontal direction. Therefore, the movement of the wall will be away from the back fill.
11 - Question
During the passive state of plastic equilibrium, the retaining wall moves _______
a) towards the fill
b) away from the fill
c) does not change its position
d) remains in equilibrium
View Answer
Answer: a
Explanation: During the passive state of plastic equilibrium, the major principal stress denoted by σ1 is in horizontal direction and the minor principal stress σ3 is in vertical direction. Therefore, the movement of the wall will be towards the back fill.
12 - Question
In active state of plastic equilibrium, the earth pressure on the wall ________
a) increases
b) decreases
c) is zero
d) is constant
View Answer
Answer: b
Explanation: When the wall moves away from the backfill, mobilization of the internal resistance of the soil takes place in the direction away from the wall. Hence the earth pressure on the wall decreases.
13 - Question
In passive state of plastic equilibrium, the earth pressure on the wall ________
a) increases
b) decreases
c) is zero
d) is constant
View Answer
Answer: a
Explanation: In passive state of plastic equilibrium, when the wall moves towards the fill, the earth pressure increases because the shearing resistance builds up in the direction of the wall.
14 - Question
In active state, the failure wedge shows ____________
a) downward movement
b) upward movement
c) left side movement
d) right side movement
View Answer
Answer: a
Explanation: In the active state of plastic equilibrium, the wall moves away from the fill because of the mobilization of the internal resistance of the soil taking place in the direction away from the wall. Due to this the failure wedge shows downward movement.
15 - Question
In passive state, the failure wedge shows ____________
a) downward movement
b) upward movement
c) left side movement
d) right side movement
View Answer
Answer: b
Explanation: In passive state of plastic equilibrium, the wall moves towards the fill because of the shearing resistance that builds up in the direction of the wall. Due to this the failure wedge shows upward movement.