Geotechnical Engineering MCQ Unit 6 | Basic Civil Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Geotechnical Engineering”.

Questions and Answers

Unit 6

1. A basic type of failure at a finite slope may occur due to ___________
a) Slope failure and Base failure
b) Toe failure
c) None of the mentioned
d) All of the mentioned
View Answer

Answer: a
Explanation: The two basic types of failure of a finite slope may occur: (i) slope failure (ii) base failure.

2. If the failure occurs along a surface of sliding that intersect the slope at its toe, the slide is known as ___________
a) Base failure
b) Slope failure
c) Face failure
d) All of the mentioned
View Answer

Answer: b
Explanation: If the failure occurs along a sliding that intersects the slopes at or above its toe, the slide is known as slope failure.

3. The types of slip surface or failure surfaces are ____________
a) 4
b) 2
c) 3
d) 5
View Answer

Answer: c
Explanation: The types of failure surface are: i) Planar failure surface ii) circular failure surface iii) Non-circular failure surface.

4. The ratio of total depth to depth H is called _________
a) Depth factor
b) Slope depth
c) Depth failure
d) Base failure
View Answer

Answer: a
Explanation: The ratio of the total depth (H + D) to depth H is called the depth factor Df.

5. The depth factor Df for toe failure is ___________
a) Df > 1
b) Df < 1
c) Df = 1
d) Df = 0
View Answer

Answer: c
Explanation: For toe failure, Df = 1; for base failure, Df > 1.

6. Planar surface commonly occur in __________
a) Embankment with specific plane of weakness
b) All embankments
c) Soil deposit
d) Foundation of infinite depth
View Answer

Answer: a
Explanation: Planar failure surface may commonly occur in a soil deposit or embankment with a specific plane of weakness.

7. The stability of a finite slope can be investigated by which of the following method?
a) Bishop’s method
b) Swedish circle method
c) Friction circle method
d) All of the mentioned
View Answer

Answer: d
Explanation: The stability of a finite slope can be investigated by the following methods:

i) Culmann’s method of planar failure surface
ii) The Swedish circle method
iii) Friction circle method
iv) Bishop’s method.

8. According to Bennet, non-circular slip surface may arise in ___________
a) Non homogeneous dam
b) Embankment dams
c) Homogeneous dam
d) Soil deposit with a specific plane of weakness
View Answer

Answer: c
Explanation: According to Bennet (1951), non-circular or composite slip surface may arise in homogeneous dam have foundation of infinite depth, rigid boundary planes of maximum and presence of stronger or weaker layer.

9. The rupture mass sliding down a surface in a definite pattern resembles __________
a) Curve
b) Cycloid
c) Ellipse
d) Circle
View Answer

Answer: b
Explanation: Collin observed that the rupture mass slide down a sliding surface, in a definite pattern resembling that of a cycloid.

10. In stability computation, the curve representing the real surface of sliding is usually replaced by ___________
a) Arc of circle and Logarithmic failure
b) Cycloid
c) None of the mentioned
d) All of the mentioned
View Answer

Answer: a
Explanation: Failure of finite slopes occurs along a curved surface. In stability computation, the curve is represented by an arc of a circle or logarithmic scale.

1. Rectangular plot method has been suggested by _________
a) Culmann
b) Bishop
c) Singh
d) Terzaghi
View Answer

Answer: c
Explanation: A simplified rectangular plot method for finding the stability of slopes was suggested by Singh in 1962.

2. The slip circle having the minimum factor of safety is called ___________
a) Critical circle
b) Failure slip circle
c) Critical slip circle
d) None of the mentioned
View Answer

Answer: c

Explanation: A number of trial critical slip circle are chosen against sliding and factor of safety of each is computed. The circle having the minimum factor of safety is the critical slip circle.

3. In Swedish circle method ___________ analysis cases are considered.
a) φC = 0
b) C – φ and φu = 0
c) None of the mentioned
d) All of the mentioned
View Answer

4. When does the critical condition of d/s slope, occur in reservoir?
a) Reservoir is full
b) Pore pressure is high
c) Steady seepage does not occur
d) All of the mentioned
View Answer

Answer: a
Explanation: Critical condition of d/s slope occurs when the reservoir is full and percolation is at its maximum rate.

5. In the rectangular plot method if there are n-slices, the total number of ordinates will be ____________
a) n – 1
b) n
c) n – 2
d) None of the mentioned
View Answer

Answer: a
Explanation: In the rectangular plot method if there are n-slices, the total number of ordinates will be (n-1), the ordinates at the end of the last strip being zero.

6. Stability of slopes of an earth dam is tested under, which of the following condition?
a) Stability of downstream slope during steady seepage and Stability of upstream slope during a sudden drawdown
b) Stability of upstream slope during sudden seepage
c) None of the mentioned
d) All of the mentioned
View Answer

Answer: a
Explanation: The stability of slopes of an earth dam is tested under the following conditions:
i) Stability of downstream slope during steady seepage
ii) Stability of upstream slope during a sudden drawdown
iii) Stability of upstream and downstream slopes during and immediately after construction.

7. When a dam is built of impervious compressible soil, water is entrapped in the pore space due to ___________
a) Excessive pore pressure
b) Volume change in the soil mass
c) Low shear strength of soil
d) Unstable soil mass
View Answer

Answer: b
Explanation: When a dam is built of relatively impervious compressible soil, excess pore pressure develops in the air and water entrapped in the pore pressure. This is because the soil mass undergoes a change in the soil due to compaction of the dam construction and also due to a down weight.

8. The area of U-diagram in finding stability of D/S slope during steady seepage, can be measured by ___________
a) Planimeter and Rectangular plot method
b) Fellinious method
c) None of the mentioned
d) All of the mentioned
View Answer

Answer: a
Explanation: The area of U-diagram can be measured with the help of a planimeter, or else the rectangular plot method can be utilized.

9. The magnitude and distribution of pore water pressure on a slip surface can be calculated from ___________
a) Pressure net
b) Test data
c) Graphical method
d) Rectangular plot method
View Answer

Answer: a
Explanation: The magnitude and distribution of pore water pressure on a likely slip surface is estimated from pressure net which are developed from the flow net.

10. The pore water pressure at any point on the slip surface is represented by ____________
a) Piezometric head
b) Pore pressure
c) Factor of safety
d) Failure plane
View Answer

Answer: a
Explanation: The pore water pressure at any point is represented by the piezometric head hw at that point.

11. The estimation of construction pore pressure can be made with the help of ___________
a) Swedish circle method
b) Bishop’s method
c) Hilf’s equation
d) Rectangular plot method
View Answer

Answer: c
Explanation: The estimation of the construction pore pressure is made with the help of Hilf’s equation:
u = pa Δ / (va + hc γw – Δ).

12. In Hilf’s equation ‘u = pa Δ / (va + hc γw – Δ)’, hc refers to __________
a) Induced pore pressure
b) Henry’s constant
c) Volume of pore water
d) Volume of air voids
View Answer

Answer: b
Explanation: In Hilf’s equation hc refers to Henry’s constant of solubility of air in water by volume (= 0.02 at 68°F).

1. In the friction circle method, it is assumed that the resultant reaction is ___________ to the friction circle.
a) Perpendicular
b) Tangential
c) Parallel
d) None of the mentioned
View Answer

2. The friction circle may be also referred as __________
a) φ-circle
b) Plane circle
c) Cohesion circle
d) All of the mentioned
View Answer

Answer: a
Explanation: The friction circle having radius r sin φ is also called as φ-circle.

3. A circle is considered to be a critical slip circle, if it has ___________
a) Maximum factor of safety
b) Minimum factor of safety
c) Maximum radius
d) All of the mentioned
View Answer

Answer: b
Explanation: The circle giving minimum factor of safety Fc is considered as a critical slip circle.

4. The factor of safety with respect to cohesion is given by the equation ____________
a) FC = HC / H
b) FC = C / Cm
c) FC = τf / τ
d) All of the mentioned
View Answer

Answer: b
Explanation: The factor of safety Fc with respect to cohesive strength, based on the assumption that the frictional strength has been fully mobilized, is given by
FC = C / Cm.

5. The friction circle method assumes the failure surface as ___________
a) Cycloid
b) Curve
c) Arc of circle
d) None of the mentioned
View Answer

Answer: c
Explanation: Similar to Culmann’s method, the friction circle method also assumes the failure surface as the arc of circle.

6. The forces acting on a sliding wedge are ___________
a) Weight of the wedge
b) Total frictional force
c) Total cohesive resistance
d) All of the mentioned
View Answer

Answer: d
Explanation: The forces acting on a sliding wedge are i) the weight of the wedge ii) the total frictional resistance or resultant, and iii) total cohesive resistance along the slip circle.

7. The factor of safety Fc with respect to cohesive strength is based on the assumption that ___________
a) Frictional force is fully mobilized
b) Frictional force is zero
c) Total cohesive resistance is zero
d) All of the mentioned
View Answer

Answer: a
Explanation: The factor of safety with respect to cohesive strength, based on the assumption that frictional force has been fully mobilized, and the equation is given by FC = C / Cm.

8. The factor K, in the radius of the friction circle(Kr sin φ) depends on ____________
a) Radius of the frictional circle
b) Frictional resistances offered
c) Cohesive resistance
d) Central angle of the slip arc
View Answer

Answer: d
Explanation: In the frictional circle radius of Kr sin φ, the factor K depends on the central angle δ of the slip arc.

1. Rectangular plot method has been suggested by _________
a) Culmann
b) Bishop
c) Singh
d) Terzaghi
View Answer

Answer: c
Explanation: A simplified rectangular plot method for finding the stability of slopes was suggested by Singh in 1962.

2. The slip circle having the minimum factor of safety is called ___________
a) Critical circle
b) Failure slip circle
c) Critical slip circle
d) None of the mentioned
View Answer

Answer: c
Explanation: A number of trial critical slip circle are chosen against sliding and factor of safety of each is computed. The circle having the minimum factor of safety is the critical slip circle.

3. In Swedish circle method ___________ analysis cases are considered.
a) φC = 0
b) C – φ and φu = 0
c) None of the mentioned
d) All of the mentioned
View Answer

Answer: b
Explanation: In Swedish slip circle method two cases are considered: i) analysis of purely cohesive soil (φu = 0) and ii) analysis of a soil possessing both cohesion and friction (C-φ analysis).