Soil Mechanics Questions and Answers Part-31

1. What are the types of water flow in the soil
a) Turbulent flow and Laminar flow
b) Linear flow
c) None of the mentioned
d) All of the mentioned

Answer: a
Explanation: The flow of water through soils may be either a laminar flow or turbulent flow.

2. In what way, do the fluid particles travel in a turbulent flow?
a) Twisting
b) Crossing
c) Re-crossing
d) Definite path

Answer: d
Explanation: In laminar flow, each fluid particles travels along a definite path which never crosses the path of any other particles.

3. Gravels are __________ permeable.
a) Highly
b) Least
c) Partially
d) All of the mentioned

Answer: a
Explanation: The pore size in gravel is larger, hence the gravels are highly permeable than sand which is least permeable.

4. The law of flow of water through the soil was first studied by ___________
a) Taylor
b) Darcy
c) Lambe
d) Khosla

Answer: b
Explanation: In 1856, Darcy studied the law of flow of water through soil and demonstrated experimentally the laminar flow conditions.

5. Which of the following equation defines Darcy’s law?
a) q=KA
b) q=K/A
c) q=K i A
d) q=K i/A

Answer: c
Explanation: According to Darcy’s law, the rate of flow or discharge per unit area is proportional to the hydraulic gradient.
q α i
q = K i A, where K =Darcy’s coefficient of permeability
A = total cross-sectional area.

6. Coefficient of permeability or simple permeability is expressed in terms of ____________
a) cm/sec
b) m/day
c) feet/day
d) all of the mentioned

Answer: d
Explanation: As the dimension of the coefficient of permeability k are same as those of velocity. It is expressed in terms of cm/sec or m/day or feet/day.

7. The co-efficient of permeability of fine sand is ____________
a) 1.0 and greater
b) 1×10-6 and smaller
c) 1×10-2 to 5×10-3
d) 5×10-2 to 1×10-3

Answer: d
Explanation: For fine sand, the coefficient of permeability is 0.05 to 0.001 cm /sec or
5×10-2 to 1×10-3.

8. Darcy’s law is valid for only ___________
a) Laminar flow
b) Turbulent flow
c) Hydraulic flow
d) All of the mentioned

Answer: a
Explanation: Darcy’s law of linear dependency between the velocity of flow and hydraulic agent is valid for only laminar flow conditions in the soil.

9. Darcy’s law is valid as long as it is equal to or less than ____________
a) 1
b) 0
c) 0.1
d) 2

Answer: a
Explanation: In 1933, Lewis and Barnes demonstrated experimentally that Darcy’s law is valid if it is ≤ 1.

10. Stiff clays are ______________ permeable.
a) Highly
b) Least
c) Partially
d) None of the mentioned

Answer: b
Explanation: As stiff clay does not contain any porous materials, it may be termed as least permeable or impermeable.