Excavation Techniques in Hard Rock

Soil Mechanics Quiz: Test Your Knowledge

1. What is the unit weight of water?

a) 9.81 kN/m³

b) 10.81 kN/m³

c) 9.00 kN/m³

d) 8.00 kN/m³

Correct Answer: a) 9.81 kN/m³
Water has a unit weight of approximately 9.81 kN/m³ at standard conditions.

2. If the sand in situ is in its densest state, then the relative density of sand is

a) zero

b) 1

c) Between 0 and 1

d) >1

Correct Answer: b) 1
At the densest state, emin and Id = 1

3. Uniformity coefficient of soil is

a) always less than 1

b) = 1

c) equal of less than 1

d) equal of more than 1

Correct Answer: d) equal of more than 1
For well-graded gravel Cu > 4 and for well-graded sand Cu > 6.

4. If the plasticity index of the soil mass is zero, the soil is

a) Sand

b) Silt

c) Clay

d) Clayey silt

Correct Answer: a) Sand
Sand is cohesionless, so the plasticity index = 0.

5. Which of the following methods is suitable for the determination of permeability of coarse-grained soil?

a) Falling head permeability test

b) Constant head permeability test

c) None of the above

d) Both a and b

Correct Answer: b) Constant head permeability test
Falling head permeability test for fine-grained soil and constant head permeability test for coarse-grained soil.

6. Phreatic line in an earthen dam is:

a) straight line

b) parabolic

c) circular

d) elliptical

Correct Answer: b) parabolic
The phreatic line in an earthen dam follows a parabolic path.

7. With increase in temperature coefficient of permeability

a) decreases

b) does not change

c) increases

d) both a and c

Correct Answer: c) increases
With increase in temperature coefficient of permeability increases as density decreases with temperature.

8. A soil having particle of nearly same size is

a) well graded

b) uniformally graded

c) poorly graded

d) gap graded

Correct Answer: b) uniformally graded
Well graded soil has mixture of particles of all sizes, Cu>4 for gravel and Cu>6 for sand

9. When degree of consolidation is 50% its time factor is

a) 0.2

b) 0.5

c) 1

d) 0.848

Correct Answer: a) 0.2
Time factor for 50% consolidation is 0.196 Time factor for 90% consolidation is 0.848

10. A soil has liquid limit 45% and lies above A-line. The group symbol as per IS classification system

a) MI

b) CL

c) MH

d) CI

Correct Answer: d) CI
Above A line - Clay, Below A line - Silt or Organic

liquid limit

less then 35 - Low plastic, More then 50 - High plastic, 30 - 50 - Intermediate or medium plastic

Soil lies above A line and liquid limit 45 % so Clay of intermideate plasticity - CI