Soil Mechanics MCQs SSC JE

 

SOIL MECHANICS – 100 MCQs

(SSC JE | Easy–Moderate Level)

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TOPIC 1: BASIC CONCEPTS & SOIL PROPERTIES (Q1–Q15)

1. Soil is a ______ material.
   A) Homogeneous
   B) Isotropic
   C) Heterogeneous
   D) Elastic

2. The void ratio of soil is defined as:
   A) Volume of voids / Total volume
   B) Volume of solids / Total volume
   C) Volume of voids / Volume of solids
   D) Volume of air / Volume of water

3. Porosity (n) is related to void ratio (e) by:
   A) $n = \frac{e}{1+e}$
   B) $n = \frac{1}{1+e}$
   C) $n = \frac{e}{1-e}$
   D) $n = \frac{1}{e}$

4. If the degree of saturation is 100%, soil is called:
   A) Dry soil
   B) Moist soil
   C) Saturated soil
   D) Submerged soil

5. Unit weight of water is:
   A) 9.81 kN/m³
   B) 10 kN/m³
   C) 1 kN/m³
   D) 1000 kN/m³

6. Which phase is absent in dry soil?
   A) Solid
   B) Water
   C) Air
   D) Void

7. Specific gravity of soil solids generally lies between:
   A) 1.0 – 1.5
   B) 2.0 – 2.8
   C) 3.0 – 4.0
   D) 4.0 – 5.0

8. Water content is the ratio of:
   A) Weight of water / Weight of solids
   B) Weight of water / Total weight
   C) Volume of water / Volume of solids
   D) Volume of voids / Volume of solids

9. Bulk unit weight includes:
   A) Only solids
   B) Solids + water
   C) Solids + air
   D) Solids + water + air

10. If soil has high void ratio, it is:
    A) Dense
    B) Loose
    C) Hard
    D) Impermeable

11. Degree of saturation is:
    A) $\frac{V_w}{V_s}$
    B) $\frac{V_w}{V_v}$
    C) $\frac{V_v}{V}$
    D) $\frac{V_s}{V_v}$

12. For saturated soil, which is zero?
    A) Void ratio
    B) Porosity
    C) Air content
    D) Water content

13. Submerged unit weight =
    A) γsat – γw
    B) γd + γw
    C) γw – γsat
    D) γsat + γw

14. The three phases of soil are:
    A) Solid, liquid, gas
    B) Solid, water, air
    C) Rock, soil, water
    D) Air, sand, clay

15. Which parameter affects compressibility most?
    A) Void ratio
    B) Specific gravity
    C) Unit weight
    D) Water content

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🔹 TOPIC 2: SOIL CLASSIFICATION (Q16–Q30)

16. Soil classification helps in:
    A) Excavation
    B) Identification of soil behavior
    C) Transportation
    D) Cost estimation

17. Which system is widely used in India?
    A) AASHTO
    B) BIS system
    C) Unified Soil Classification
    D) British system

18. According to IS classification, soils are divided into:
    A) 2 groups
    B) 3 groups
    C) 4 groups
    D) 5 groups

19. Coarse-grained soils have more than:
    A) 50% passing 75 micron
    B) 50% retained on 75 micron
    C) 75% passing 4.75 mm
    D) 25% passing 75 micron

20. Gravel size is:
    A) > 4.75 mm
    B) < 0.075 mm
    C) 0.075–4.75 mm
    D) > 2 mm

21. Plasticity index =
    A) LL – SL
    B) LL – PL
    C) PL – SL
    D) WL – PL

22. A soil with PI = 0 is:
    A) Clay
    B) Silt
    C) Sand
    D) Non-plastic soil

23. Which chart is used in soil classification?
    A) Mohr circle
    B) Casagrande plasticity chart
    C) Flow curve
    D) Stress path

24. High plastic clay is denoted as:
    A) CL
    B) CH
    C) ML
    D) MH

25. Which soil has maximum compressibility?
    A) Sand
    B) Gravel
    C) Clay
    D) Silt

26. A well-graded soil has:
    A) Uniform size particles
    B) Wide range of sizes
    C) Only coarse particles
    D) Only fine particles

27. Coefficient of uniformity (Cu) should be for well graded sand:
    A) < 2
    B) > 4
    C) = 1
    D) > 10

28. Which soil is best for foundation?
    A) Clay
    B) Silt
    C) Well graded sand
    D) Organic soil

29. Expansive soil is generally:
    A) Sand
    B) Gravel
    C) Clay
    D) Silt

30. Black cotton soil is rich in:
    A) Kaolinite
    B) Montmorillonite
    C) Illite
    D) Quartz

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🔹 TOPIC 3: ATTERBERG LIMITS (Q31–Q45)

31. Liquid limit is the water content at which soil changes from:
    A) Solid to semi-solid
    B) Semi-solid to plastic
    C) Plastic to liquid
    D) Liquid to gas

32. Plastic limit is the water content at which soil:
    A) Crumbles at 3 mm diameter
    B) Flows in Casagrande cup
    C) Shrinks
    D) Becomes liquid

33. Shrinkage limit is when further loss of water:
    A) Increases volume
    B) Decreases volume
    C) Does not change volume
    D) Increases weight

34. Plasticity index indicates:
    A) Strength of soil
    B) Compressibility
    C) Range of plasticity
    D) Density

35. If PI is high, soil is:
    A) Sand
    B) Silt
    C) Clay
    D) Gravel

36. Soil with LL > 50% is:
    A) Low plastic
    B) Medium plastic
    C) High plastic
    D) Non-plastic

37. Which test finds LL?
    A) Cone penetration test
    B) Casagrande apparatus
    C) Proctor test
    D) Permeability test

38. Plasticity chart separates:
    A) Sand and gravel
    B) Clay and silt
    C) Organic and inorganic soil
    D) Fine and coarse soil

39. If PI = 5, soil is:
    A) Highly plastic
    B) Medium plastic
    C) Slightly plastic
    D) Non-plastic

40. Shrinkage ratio is:
    A) Change in volume / change in water content
    B) Change in volume / original volume
    C) Change in water / volume change
    D) Weight of soil / volume

41. Liquid limit test is done by:
    A) Rolling threads
    B) Dropping cup
    C) Penetration
    D) Sieving

42. Plastic limit test is done by:
    A) Cone penetration
    B) Casagrande cup
    C) Rolling soil threads
    D) Compression

43. At shrinkage limit, soil becomes:
    A) Brittle
    B) Elastic
    C) Saturated
    D) Liquid

44. High LL indicates:
    A) Low compressibility
    B) High compressibility
    C) High permeability
    D) Low strength

45. PI = LL – PL measures:
    A) Toughness
    B) Plasticity range
    C) Shrinkage
    D) Flow index

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🔹 TOPIC 4: PERMEABILITY & SEEPAGE (Q46–Q60)

46. Permeability depends on:
    A) Soil texture
    B) Void ratio
    C) Grain size
    D) All of these

47. Darcy’s law is valid for:
    A) Laminar flow
    B) Turbulent flow
    C) Seepage failure
    D) Capillary flow

48. Unit of coefficient of permeability is:
    A) m²
    B) m/s
    C) N/m²
    D) kg/m³

49. Clay has ______ permeability.
    A) High
    B) Medium
    C) Low
    D) Very high

50. Constant head test is suitable for:
    A) Clay
    B) Silt
    C) Sand
    D) Peat

51. Falling head test is suitable for:
    A) Gravel
    B) Sand
    C) Clay
    D) Coarse sand

52. Seepage velocity is:
    A) Discharge velocity × porosity
    B) Discharge velocity / porosity
    C) Discharge velocity × void ratio
    D) Same as discharge velocity

53. Critical hydraulic gradient is when:
    A) Soil becomes dense
    B) Soil boils
    C) Soil compacts
    D) Soil dries

54. Piping failure occurs due to:
    A) Excess load
    B) High seepage force
    C) Low density
    D) Compaction

55. Quick sand condition occurs when:
    A) i > ic
    B) i < ic
    C) i = 0
    D) i < 1

56. Flow net consists of:
    A) Flow lines & equipotential lines
    B) Stress lines
    C) Contours
    D) Water lines

57. Flow lines represent:
    A) Direction of seepage
    B) Pressure
    C) Velocity
    D) Discharge

58. Equipotential lines represent:
    A) Equal head
    B) Equal velocity
    C) Equal pressure
    D) Equal discharge

59. Discharge through soil is proportional to:
    A) Area only
    B) Hydraulic gradient
    C) Permeability
    D) All of these

60. Which soil has maximum permeability?
    A) Clay
    B) Silt
    C) Sand
    D) Gravel

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🔹 TOPIC 5: COMPACTION (Q61–Q75)

61. Compaction improves:
    A) Strength
    B) Permeability
    C) Compressibility
    D) All of these

62. Compaction is achieved by:
    A) Drainage
    B) Loading
    C) Rolling
    D) Vibration

63. Maximum dry density occurs at:
    A) Zero water content
    B) Optimum moisture content
    C) Saturation
    D) Shrinkage limit

64. Proctor test determines:
    A) Permeability
    B) OMC & MDD
    C) Shear strength
    D) Settlement

65. Heavy compaction gives:
    A) Lower MDD
    B) Higher MDD
    C) Same MDD
    D) Zero MDD

66. Increase in compaction energy causes:
    A) Increase in OMC
    B) Decrease in OMC
    C) No change
    D) Random change

67. For clayey soil, best compaction is by:
    A) Vibratory roller
    B) Sheep foot roller
    C) Smooth wheel roller
    D) Grid roller

68. For sandy soil, best compaction is by:
    A) Sheep foot roller
    B) Pneumatic roller
    C) Vibratory roller
    D) Tamping

69. Which curve is obtained in Proctor test?
    A) Stress-strain
    B) Flow curve
    C) Compaction curve
    D) Permeability curve

70. Dry density =
    A) Bulk density × (1+w)
    B) Bulk density / (1+w)
    C) Bulk density – w
    D) Bulk density × w

71. Compaction reduces:
    A) Void ratio
    B) Strength
    C) Stability
    D) Density

72. OMC means:
    A) Maximum moisture content
    B) Minimum moisture content
    C) Optimum moisture content
    D) Original moisture content

73. Higher MDD indicates:
    A) Loose soil
    B) Dense soil
    C) Weak soil
    D) Soft soil

74. Zero air voids line represents:
    A) Saturation curve
    B) Maximum density line
    C) Minimum density line
    D) Porosity curve

75. Field compaction is checked by:
    A) Sieve analysis
    B) Plate load test
    C) Core cutter test
    D) Shear test

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🔹 TOPIC 6: SHEAR STRENGTH OF SOIL (Q76–Q90)

76. Shear strength depends on:
    A) Cohesion
    B) Friction
    C) Both
    D) Density only

77. Mohr-Coulomb equation is:
    A) τ = σ
    B) τ = c + σ tan φ
    C) τ = σ tan φ
    D) τ = c

78. For sand, cohesion is:
    A) High
    B) Moderate
    C) Zero
    D) Negative

79. Direct shear test gives:
    A) Permeability
    B) Consolidation
    C) Shear strength
    D) Density

80. Triaxial test is better than direct shear because:
    A) Simpler
    B) More accurate
    C) Cheaper
    D) Faster

81. In undrained test, drainage is:
    A) Allowed
    B) Not allowed
    C) Partial
    D) Controlled

82. Angle of internal friction is due to:
    A) Shape of particles
    B) Size of particles
    C) Density
    D) Moisture

83. Clay has:
    A) High φ
    B) Low φ
    C) Zero φ
    D) Infinite φ

84. Which soil has highest shear strength?
    A) Loose sand
    B) Dense sand
    C) Soft clay
    D) Silt

85. Unconfined compression test is for:
    A) Sand
    B) Gravel
    C) Clay
    D) Silt

86. UCS value is equal to:
    A) 2c
    B) c
    C) φ
    D) ½c

87. Shear failure in soil occurs when:
    A) Stress > strength
    B) Stress < strength
    C) Stress = zero
    D) Strength increases

88. In cohesive soil, shear strength mainly depends on:
    A) Friction
    B) Cohesion
    C) Density
    D) Water

89. Which test is quick?
    A) Triaxial
    B) Direct shear
    C) Unconfined compression
    D) Consolidation

90. Factor of safety is ratio of:
    A) Stress/strength
    B) Strength/stress
    C) Load/area
    D) Area/load

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🔹 TOPIC 7: CONSOLIDATION & SETTLEMENT (Q91–Q100)

91. Consolidation is due to:
    A) Compression of solids
    B) Expulsion of air
    C) Expulsion of water
    D) Evaporation

92. Consolidation occurs mainly in:
    A) Sand
    B) Gravel
    C) Clay
    D) Silt

93. Primary consolidation is due to:
    A) Air expulsion
    B) Water expulsion
    C) Soil creep
    D) Elastic rebound

94. Secondary consolidation is due to:
    A) Water flow
    B) Air flow
    C) Soil creep
    D) Compaction

95. Terzaghi’s theory applies to:
    A) Sand
    B) Clay
    C) Gravel
    D) Rock

96. Coefficient of consolidation depends on:
    A) Permeability
    B) Compressibility
    C) Both
    D) Density only

97. Time for consolidation is inversely proportional to:
    A) Permeability
    B) Drainage path
    C) Thickness²
    D) Thickness

98. Settlement is maximum in:
    A) Sand
    B) Gravel
    C) Clay
    D) Rock

99. Consolidation test is also called:
    A) Triaxial test
    B) Oedometer test
    C) Shear test
    D) Plate load test

100. Immediate settlement occurs due to:
     A) Drainage
     B) Elastic deformation
     C) Creep
     D) Consolidation

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✅ ANSWER KEY

1 C | 2 C | 3 A | 4 C | 5 A | 6 B | 7 B | 8 A | 9 D | 10 B
11 B | 12 C | 13 A | 14 B | 15 A

16 B | 17 B | 18 D | 19 B | 20 A | 21 B | 22 D | 23 B | 24 B | 25 C
26 B | 27 B | 28 C | 29 C | 30 B

31 C | 32 A | 33 C | 34 C | 35 C | 36 C | 37 B | 38 B | 39 C | 40 A
41 B | 42 C | 43 A | 44 B | 45 B

46 D | 47 A | 48 B | 49 C | 50 C | 51 C | 52 B | 53 B | 54 B | 55 A
56 A | 57 A | 58 A | 59 D | 60 D

61 D | 62 C | 63 B | 64 B | 65 B | 66 B | 67 B | 68 C | 69 C | 70 B
71 A | 72 C | 73 B | 74 B | 75 C

76 C | 77 B | 78 C | 79 C | 80 B | 81 B | 82 A | 83 B | 84 B | 85 C
86 A | 87 A | 88 B | 89 C | 90 B

91 C | 92 C | 93 B | 94 C | 95 B | 96 C | 97 C | 98 C | 99 B | 100 B