Engineering Questions with Answers - Multiple Choice Questions
Earth Pressure Introduction – 1
1 - Question
The plastic state of stress when the failure is imminent was investigated by ___________
a) Rankine
b) Darcy
c) Skempton
d) Terzaghi
View Answer
Answer: a
Explanation: The plastic state of stress failure of the soil samples was studied by Rankine in the year 1860. Darcy is known for his works in the field of soil permeability.
2 - Question
___________ is used for maintaining the ground surface at different elevations.
a) Floor
b) Retaining wall
c) Ceiling
d) Roof
View Answer
Answer: b
Explanation: The retaining wall is used to resist the lateral earth pressure due to the backfill soil. It prevents the landslides by maintaining the ground surface at different elevations in hilly regions.
3 - Question
The material retained by the retaining wall is known as_________
a) roof
b) slab
c) backfill
d) footing
View Answer
Answer: c
Explanation: The material retained by the retaining wall is known as backfill. The surface of the backfill can be both horizontal as well as inclined. It should be noted that the angle does not exceed the angle of repose of the soil.
4 - Question
The backfill has its top surface ____________
a) horizontal only
b) inclined only
c) both horizontal and inclined
d) vertical only
View Answer
Answer: c
Explanation: The backfill can have its top surface as a horizontal surface or as an inclined surface. It should be noted that the angle does not exceed the angle of repose of the soil or else it will fail.
5 - Question
The portion of backfill lying above a horizontal plane of wall is called ________
a) surcharge
b) base
c) foot
d) truss
View Answer
Answer: a
Explanation: The portion of backfill lying above a horizontal plane of wall is called as the surcharge. The surcharge is a load which is imposed upon the surface of the soil close enough to the excavation to cause a lateral pressure to act on the system in addition to the basic earth pressure.
6 - Question
Surcharge angle β is ____________
a) inclination of surcharge to the vertical
b) inclination of surcharge to the normal of the wall
c) inclination of surcharge to the horizontal
d) inclination of surcharge to the tangent to the wall
View Answer
Answer: c
Explanation: The surcharge is a load which is imposed upon the surface of the soil close enough to the excavation to cause a lateral pressure to act on the system in addition to the basic earth pressure. Its inclination to the horizontal is known as Surcharge angle β.
7 - Question
A body is said to be in plastic equilibrium, if every point of it is ________
a) in the verge of failure
b) in equilibrium
c) in stable state
d) elastic state
View Answer
Answer: a
Explanation: A body is said to be in plastic equilibrium, if every point of it is in the verge of failure. The transition from the state of plastic equilibrium to the state of plastic flow represents the failure of the soil mass.
8 - Question
The stress condition during plastic equilibrium can be represented by _____________
a) σ1−σ32σ1+σ32sinφ=cosφ
b) σ1−σ32+σ1+σ32sinφ=ccosφ
c) σ1∗σ32−σ1+σ32sinφ=ccosφ
d) σ1−σ32−σ1+σ32sinφ=ccosφ
View Answer
Answer: d
Explanation: The stress condition during plastic equilibrium can be represented by the equation of Mohr-Coulomb,
σ1−σ32−σ1+σ32sinφ=ccosφ,
Where, σ1=major principal stress
σ3=minor principal stress
φ=angle of internal friction.
9 - Question
The stress condition during plastic equilibrium in terms of tangent of angle is _______
a) σ1=tan(45°+φ2)+σ3tan2(45°+φ2)
b) σ1=2c+σ3tan2(45°+φ2)
c) σ1=2ctan(45°+φ2)+σ3
d) σ1=2ctan(45°+φ2)+σ3tan2(45°+φ2)
View Answer
Answer: d
Explanation: The stress condition during plastic equilibrium can be represented by the equation of Mohr-Coulomb,
σ1−σ32−σ1+σ32sinφ=ccosφ,
since tanφ=sinφ/cosφ
∴ σ1=2ctan(45°+φ2)+σ3tan2(45°+φ2).
10 - Question
The flow value is given by ______
a) Nφ=cot2(45°+φ2)
b) Nφ=cos2(45°+φ2)
c) Nφ=tan2(45°+φ2)
d) Nφ=sin2(45°+φ2)
View Answer
Answer: c
Explanation: The flow value is given by,
Nφ=tan2(45°+φ2),
where, Nφ=flow value
φ=angle of internal friction.
11 - Question
The plastic equilibrium stress equation in terms of flow valve is _____
a) σ1=2c∛Nφ+σ3 Nφ
b) σ1=2c√Nφ+σ3 Nφ
c) σ1=2cNφ-σ3 Nφ
d) σ1=Nφ+σ3 Nφ
View Answer
Answer: b
Explanation: The stress condition during plastic equilibrium is given by,
σ1=2ctan(45°+φ2)+σ3tan2(45°+φ2),
since, Nφ=tan2(45°+φ2),
∴ σ1=2c√Nφ+σ3 Nφ.
12 - Question
The Mohr Coulomb equation in terms of stress components in x-z plane is ______________
a) ((σz−σx2)2+τ2xz))−−−−−−−−−−−−−√−σz+σx2sinφ=ccosφ
b) ((σz−σx2)2+τ2xz))−−−−−−−−−−−−−√σz+σx2sinφ=ccosφ
c) ((σz−σx2)2+τ2xz))−−−−−−−−−−−−−√=ccosφ
d) ((σz−σx2)2+τ2xz))−−−−−−−−−−−−−√−σz+σx2sinφ=cosφ
View Answer
Answer: a
Explanation: The Mohr Coulomb equation is given by,
σ1−σ32−σ1+σ32sinφ=ccosφ,
Where, σ_1=major principal stress and σ3=minor principal stress.
∴ in terms of stress components in x-z plane it is,
((σz−σx2)2+τ2xz))−−−−−−−−−−−−−√−σz+σx2sinφ=ccosφ,
where, σz=stress in z-direction
σx= stress in x-direction.
13 - Question
Combing the three equations, ((σz−σx2)2+τ2xz))−−−−−−−−−−−−−√−σz+σx2sinφ=ccosφ, ∂σx∂x+∂τxz∂z=0, and ∂τxz∂x+∂σx∂z+γ=0, lead to the equation called ___________
a) Kolter’s equation
b) Terzaghi’s equation
c) Darcy’s equation
d) Skempton’s equation
View Answer
Answer: a
Explanation: The material just in the verge of flowing plastically is still in static equilibrium and will satisfy the equations of, ∂σx∂x+∂τxz∂z=0,and∂τxz∂x+∂σx∂z+γ=0. These equations with the Mohr Coulomb equation give the Kolter’s equation.
14 - Question
The solution of Kolter’s equation gives ____________
a) permeability of soil
b) orientation of slip lines
c) specific gravity of grains
d) seepage pressure
View Answer
Answer: b
Explanation: The solution of Kolter’s equation for a given boundary condition gives the orientation of slip planes together with the stress at each point at the failure zone.
15 - Question
In active state, the major principal stress σ1 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 major principal stress denoted by σ1 is in vertical direction. While in the passive state, the major principal stress σ1 is in horizontal direction.