250+ TOP MCQs on Geotechnical Engineering and Answers

Basic Civil Engineering Multiple Choice Questions on “Geotechnical Engineering”.

1. Water content is given by:
a) Weight of water/mass of soil
b) Mass of water/mass of solid
c) Mass of water/mass of soil
d) Mass of water/weight of solid
Answer: b
Clarification: In Geotechnical Engineering, water content is an important parameter for analysing the soil. It is expressed as mass of water divided by mass of solids. It is denoted by w and expressed in %.

2. Who is the father of Geotechnical Engineering?
a) Christian Otto Mohr
b) Clausius Cleyperon
c) John Smith
d) Karl Von Terzaghi
Answer: d
Clarification: He was an Austrian civil engineer and geologist. Most of the findings in geotechnical engineering and soil properties are done by him.

3. According to Darcy’s Law:
a) q=iA
b) q=kA
c) q∞iA
d) q∞kA
Answer: c
Clarification: Darcy’s Law states that the rate of flow per unit time is proportional to a hydraulic gradient. q∞iA is the mathematical representation of the law.

4. Triaxial compression test is used to find __________ of soil.
a) Compressive strength
b) Permeability
c) Specific gravity
d) Shear strength
Answer: d
Clarification: There are 4 methods available to measure shear strength of soil – direct shear, triaxial compression, unconfined compression and vane shear test. Triaxial compression test is the most accurate one.

5. ____________ index is used to find settlement of soil.
a) Compression
b) Expansion
c) Recompression
d) Reloading
Answer: a
Clarification: A plot is made between void ratio (e) and log effective stress (logσ). It shows different curves corresponding to loading, unloading and reloading of soil. Compression index Cc= – ∆e∆logσ

6. Which of the following does not happen when compaction is done?
a) Permeability decreases
b) Water content increases
c) Shear strength decreases
d) Compressibility decreases
Answer: c
Clarification: On compaction of a soil mass, the shear strength is increased. It is tightly and firmly compacted and offers resistance to deformation and flow.

7. ____________ is the measure of loss of strength with remoulding, with water content unchanged.
a) Compressibility
b) Sensitivity
c) Stability
d) Thixotropy
Answer: b
Clarification: Sensitivity values range from 1-16. For an insensitive soil, it is 1. A soil with sensitivity above 16, is termed as quick.

8. In Geotechnical Engineering, soil is considered as a _________ phase material.
a) 3
b) 2
c) 1
d) 4
Answer: a
Clarification: Soil is a 3 phase material. It consists of solids, water and air voids. It is represented in a 3 phase diagram with volume on left side and mass on the right side.

9. Fine particles are those particles with size less than _______ mm diameter.
a) 0.023
b) 0.090
c) 0.075
d) 4.75
Answer: c
Clarification: Fine particles should pass through 75μ IS sieve. Fine particles include clay, silt and organic content in a soil mass.

10. The mass density of water at 4oC is:
a) 1000g/ml
b) 1kg/m3
c) 1000Mg/m3
d) 1000kg/m3
Answer: d
Clarification: Mass density is the ratio of mass of water to volume of water. At 4oC, it is 1g/ml or 1000kg/m3 or 1Mg/m3.

11. Percentage air voids is denoted as:
a) v
b) na
c) s
d) av
Answer: b
Clarification: Percentage air voids is the ratio of volume of air in voids to total volume of soil. It is denoted by na and expressed as a %.

12. Porosity and void ratio are related by:
a) e = n(1-n)
b) n = e(1-e)
c) 1-e = n
d) (1+n)n = e-1
Answer: a
Clarification: Void ratio is e and porosity is n. Another relationship between the two is
n = e(1+e)

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