Soil Mechanics Chapter 3: Classification of Soil – 20 PYQs Quiz with Answers

Soil Mechanics – Chapter 3

Classification of Soil | 20 PYQ-Based MCQs | Interactive Quiz

Chapter 3: Classification of Soil
20 previous-year-pattern questions covering IS soil classification, USCS, grain size, grading, plasticity chart, A-line and group symbols. हर question 1 mark का है.

PYQ Note: Questions are presented in concise exam-style wording. Exam/year labels identify the previous-year source/paper tradition used for this practice set.

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SSC JE 2017

1. According to IS soil classification system, a soil is coarse-grained if more than ____ percent of the total material is retained on 75 micron sieve.

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

Answer: B. IS classification divides soil into coarse-grained and fine-grained based on the 75 μm sieve; more than 50% retained means coarse-grained.

SSC JE 2017

2. In Unified Soil Classification System, the symbol 'M' represents:

A) Clay B) Silt C) Sand D) Organic soil

Answer: B. In USCS, M denotes inorganic silt.

SSC JE 2018

3. In USCS, the symbol 'C' is used for:

A) Coarse sand B) Clay C) Gravel D) Capillary soil

Answer: B. C = clay and M = silt in the USCS group-symbol system.

SSC JE 2018

4. The plasticity chart is used for classification of:

A) Fine-grained soils B) Coarse-grained soils C) Gravels only D) Sands only

Answer: A. The plasticity chart primarily classifies fine-grained soils using liquid limit and plasticity index.

SSC JE 2019

5. A soil having liquid limit greater than 50% is classified as:

A) Low plasticity soil B) Intermediate plasticity soil C) High plasticity soil D) Non-plastic soil

Answer: C. In IS/USCS-style classification, LL above 50% corresponds to high plasticity (H).

SSC JE 2019

6. The group symbol CH represents:

A) Inorganic clay of high plasticity B) Inorganic clay of low plasticity C) Inorganic silt of high plasticity D) Organic clay of low plasticity

Answer: A. C = clay and H = high plasticity.

SSC JE 2017

7. For a well-graded gravel, the coefficient of uniformity C_u should be:

A) Less than 2 B) Less than 4 C) Greater than 4 D) Equal to 1

Answer: C. For well-graded gravel, C_u > 4 and 1 < C_c < 3.

SSC JE 2018

8. For a well-graded sand, the coefficient of uniformity C_u should be:

A) Less than 2 B) Less than 4 C) Greater than 6 D) Equal to 1

Answer: C. For well-graded sand, C_u > 6 and 1 < C_c < 3.

SSC JE 2018

9. The coefficient of curvature C_c is given by:

A) D₆₀/D₁₀ B) D₃₀²/(D₁₀D₆₀) C) D₁₀/D₆₀ D) D₆₀²/(D₁₀D₃₀)

Answer: B. C_c = D₃₀²/(D₁₀D₆₀).

SSC JE 2017

10. A soil having C_u = 2 and C_c = 1.5 is:

A) Poorly graded B) Well graded gravel C) Well graded sand D) Gap graded only

Answer: A. C_u=2 does not satisfy the minimum well-grading criterion for gravel or sand.

SSC JE 2019

11. The A-line on the plasticity chart separates:

A) Gravel and sand B) Clays and silts C) Sand and silt D) Gravel and clay

Answer: B. On the plasticity chart, the A-line distinguishes clay-type soils from silt-type soils.

SSC JE 2020

12. The equation of A-line in the plasticity chart is:

A) PI = 0.73(LL − 20) B) PI = 0.73(LL + 20) C) PI = 0.5(LL − 20) D) PI = LL − 20

Answer: A. A-line equation: PI = 0.73(LL − 20).

SSC JE 2017

13. In IS soil classification system, the symbol GW represents:

A) Well-graded sand B) Poorly graded gravel C) Well-graded gravel D) Gravel with silt

Answer: C. G = gravel and W = well graded.

SSC JE 2018

14. The symbol SW in USCS denotes:

A) Well-graded sand B) Poorly graded sand C) Silty sand D) Sandy silt

Answer: A. S = sand and W = well graded.

SSC JE 2019

15. The group symbol GP indicates:

A) Well-graded gravel B) Poorly graded sand C) Gravel with clay D) Poorly graded gravel

Answer: D. G = gravel and P = poorly graded.

SSC JE 2020

16. A soil is classified as ML when it is:

A) Clay of low plasticity B) Organic silt C) Inorganic silt of low plasticity D) Inorganic clay of low plasticity

Answer: C. M = inorganic silt; L = low plasticity.

SSC JE 2018

17. In soil classification, the term 'well graded' means:

A) Soil has particles of one size only B) Soil has a good distribution of particle sizes C) Soil has no fines D) Soil has only fine particles

Answer: B. Well-graded soil contains a broad and continuous range of particle sizes in suitable proportions.

SSC JE 2019

18. A gap-graded soil contains:

A) Only clay particles B) Only uniformly sized particles C) An absence of one or more intermediate particle sizes D) Equal percentages of all sizes

Answer: C. Gap grading means one or more ranges of intermediate particle sizes are missing.

SSC JE 2020

19. In USCS, the symbol O represents:

A) Organic silt or clay B) Over-consolidated soil C) Organic sand only D) Oxidized soil

Answer: A. O denotes organic silt or organic clay in USCS.

SSC JE 2021

20. Which of the following is NOT a basic group symbol used in the Unified Soil Classification System?

A) G B) S C) M D) R

Answer: D. G, S, M, C and O are standard basic symbols; R is not a basic USCS group symbol.

Quiz Complete!

Quick Revision: G = Gravel, S = Sand, M = Silt, C = Clay, O = Organic. W = Well graded, P = Poorly graded, L = Low plasticity, H = High plasticity. For well-graded gravel: C_u > 4; for well-graded sand: C_u > 6; and 1 < C_c < 3.

Soil Mechanics Chapter 3 – Classification of Soil
20 PYQ-Based MCQs • Interactive Marks • Civil Engineering Competitive Exams