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

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

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

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

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

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

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

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

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)

Explanation: The stress condition during plastic equilibrium can be represented by the equation of Mohr-Coulomb,
σ1−σ32−σ1+σ32sinφ=ccosφ,
since tan⁡φ=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)

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

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

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

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

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