Soil Mechanics And Foundation MCQ Questions & Answers

1

The hydraulic head that would produce a quick condition in a sand stratum of thickness 1.5 m, specific gravity 2.67 and voids ratio 0.67 is equal to

A) 1.0m B) 1.5m C) 2.0m D) 3m

Discuss

Answer & Solution

Answer: Option B

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2

Clay layer A with single drainage and coefficient of consolidation Cv takes 6 months to achieve 50% consolidation. The time taken by clay layer B of the same thickness with double drainage and coefficient of consolidation $$\frac{{{\text{Cv}}}}{2}$$ to achieve the same degree of consolidation is

A) 3 months B) 6 months C) 12 months D) 24 months

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Answer & Solution

Answer: Option A

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3

Degree of consolidation is

A) directly proportional to time and inversely proportional to drainage path B) directly proportional to time and inversely proportional to square of drainage path C) directly proportional to drainage path and inversely proportional to time D) directly proportional to square of drainage path and inversely proportional to time

Discuss

Answer & Solution

Answer: Option B

Solution:

The degree of consolidation in soil mechanics is a measure of how much a soil sample has consolidated over time due to applied pressure.

It is directly proportional to time because the consolidation process continues as time progresses.

It is inversely proportional to the square of the drainage path because longer drainage paths result in slower consolidation.

Therefore, Option B correctly describes the relationship between the degree of consolidation, time, and drainage path.

4

Select the correct range of density index, 1_D

A) 1_D > 0 B) 1_D ≥ 0 C) 0 < 1_D < 1 D) 0 ≤ 1_D ≤ 1

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Answer & Solution

Answer: Option D

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5

For a loose sand sample and a dense sand sample consolidated to the same effective stress

A) ultimate strength is same and also peak strength is same B) ultimate strength is different but peak strength is same C) ultimate strength is same but peak strength of dense sand is greater than that of loose sand D) ultimate strength is same but peak

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Answer & Solution

Answer: Option C

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6

Within the consolidation process of a saturated clay

A) a gradual increase in neutral pressure and a gradual decrease in effective pressure takes place and sum of the two is constant B) a gradual decrease in neutral pressure and a gradual increase in effective pressure takes place and sum of the two is constant C) both neutral pressure and effective pressure decrease D) both neutral pressure and effective pressure increase

Discuss

Answer & Solution

Answer: Option B

Solution:

Understanding Consolidation in Saturated Clay:
Imagine squeezing a sponge soaked in water. The water needs time to escape.
Consolidation is similar; it's the process of water slowly leaving saturated clay under pressure.
Neutral pressure is the pressure of the water in the soil pores.
Effective pressure is the pressure that the soil particles themselves carry.
During consolidation, the total pressure stays the same. It's like the total amount of water in the sponge plus the sponge itself.
As the water escapes (reducing neutral pressure), the soil particles take on more of the load (increasing effective pressure).
Therefore, the sum of neutral pressure and effective pressure remains constant.

The Correct Answer:
Based on the above explanation, option B is correct. It accurately describes the reduction in neutral pressure and corresponding increase in effective pressure during consolidation, while maintaining a constant sum.

7

Rise of water table in cohesionless soils upto ground surface reduces the net ultimate bearing capacity approximately by

A) 25% B) 50% C) 75% D) 90%

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Answer & Solution

Answer: Option B

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8

Terzaghi’s bearing capacity factors Nc, Nq and Nr are functions of

A) cohesion only B) angle of internal friction only C) both cohesion and angle of internal friction D) none of the above

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Answer & Solution

Answer: Option B

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9

Valid range for S, the degree of saturation of soil in percentage is

A) S > 0 B) S < 0 C) 0 < S < 100 D) 0 ≤ S ≤ 100

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Answer & Solution

Answer: Option D

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10

If the natural water content of soil mass lies between its liquid limit and plastic limit, the soil mass is said to be in

A) liquid state B) plastic state C) semi-solid state D) solid state

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Answer & Solution

Answer: Option B

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Soil Mechanics And Foundation MCQ Questions & Answers | Civil Engineering