76. Coefficient of compressibility is
a) constant for any type of soil
b) different for different types of soils and also different for a soil under different states of consolidation
c) different for different types of soils but same for a soil under different states of consolidation
d) independent of type of soil but depends on the stress history of soil
Ans:b
77. The ultimate consolidation settlement of a structure resting on a soil
a) decreases with the increase in the initial voids ratio
b) decreases with the decrease in the plastic limit
c) increases with the increase in the initial voids ratio
d) increases with the decrease in the porosity of the soil
Ans:a
78. The ultimate consolidation settlement of a soil is
a) directly proportional to the voids ratio
b) directly proportional to the compression index
c) inversely proportional to the compression index
d) none of the above
Ans:b
79. A normally consolidated clay settled 10 mm when effective stress was increased from 100 kN/m2 to 200 kN/ m2. If the effective stress is further increased from 200 kN/ m2 to 400 kN/ m2, then the settlement of the same clay is
a) 10 mm
b) 20 mm
c) 40 mm
d) none of the above
Ans:a
80. Coarse grained soils are best compacted by a
a) drum roller
b) rubber tyred roller
c) sheep’s foot roller
d) vibratory roller
Ans:d
81. With the increase in the amount of compaction energy
a) optimum water content increases but maximum dry density decreases
b) optimum water content decreases but maximum dry density increases
c) both optimum water content and maximum dry density increase
d) both optimum water content and maximum dry density decrease[ES 93]
Ans:b
82. The maximum dry density upto which any soil can be compacted depends upon
a) moisture content only
b) amount of compaction energy only
c) both moisture content and amount of compaction energy
d) none of the above
Ans:c
83. For better strength and stability, the fine grained soils and coarse grained soils are compacted respectively as
a) dry of OMC and wet of OMC
b) wet of OMC and dry of OMC
c) wet of OMC and wet of OMC
d) dry of OMC and dry of OMC where OMC is optimum moisture content
Ans:b
84. Select the incorrect statement.
a) Effective cohesion of a soil can never have a negative value.
b) Effective angle of internal friction for coarse grained soils is rarely below 30°.
c) Effective angle of internal friction for a soil increases as state of compact-ness increases.
d) Effective angle of internal friction is a complicated function of mineralogy and clay size content.
Ans:a
85. 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
Ans:c
86. The shear strength of a soil
a) is directly proportional to the angle of internal friction of the soil
b) is inversely proportional to the angle of internal friction of the soil
c) decreases with increase in normal stress
d) decreases with decrease in normal stress
Ans:d
87. In a consolidated drained test on a normally consolidated clay, the volume of the soil sample during shear
a) decreases
b) increases
c) remains unchanged
d) first increases and then decreases
Ans:a
88. Skempton’s pore pressure coefficient B for saturated soil is
a) 1
b) zero
c) between 0 and 1
d) greater than 1
Ans:a
89. Shear strength of a soil is a unique function of
a) effective stress only
b) total stress only
c) both effective stress and total stress
d) none of the above
Ans:a
90. In a deposit of normally consolidated clay
a) effective stress increases with depth but water content of soil and un-drained strength decrease with depth
b) effective stress and water content increase with depth but undrained strength decreases with depth
c) effective stress and undrained strength increase with depth but water content decreases with depth
d) effective stress, water content and undrained strength decrease with depth
Ans:c
91. Select the incorrect statement. Effective angle of shearing resistance
a) increases as the size of particles increases
b) increases as the soil gradation im-proves
c) is limited to a maximum value of 45°
d) is rarely more than 30° for fine grained soil
Ans:c
92. Unconfmed compressive strength test is
a) undrained test
b) drained test
c) consolidated undrained test
d) consolidated drained test
Ans:a
93. A cylindrical specimen of saturated soil failed under an axial vertical stress of 100kN/m2 when it was laterally unconfmed. The failure plane was inclined to the horizontal plane at an angle of 45°. The values of cohesion and angle of internal friction for the soil are respectively
a) 0.5 N/mm2 and 30°
b) 0.05 N/mm2 and 0°
c) 0.2 N/mm2 and 0°
d) 0.05 N/mm2 and 45°
Ans:b
94. The angle that Coulomb’s failure envelope makes with the horizontal is called
a) cohesion
b) angle of internal friction
c) angle of repose
d) none of the above
Ans:a
95. If a cohesive soil specimen is subjected to a vertical compressive load, the inclination of the cracks to the horizontal is
a) 90°
b) 45°
c) 22.5°
d) 0°
Ans:b
96. Select the incorrect statement.
a) In a direct shear box test, the plane of shear failure is predetermined.
b) Better control is achieved on the drainage of the soil in a triaxial com-pression test.
c) Stress distribution on the failure plane in the case of triaxial compression test is uniform.
d) Unconfined compression test can be carried out on all types of soils.
Ans:d
97. If the shearing stress is zero on two planes, then the angle between the two planes is
a) 45°
b) 90°
c) 135°
d) 225°
Ans:b
98. In the triaxial compression test, the application of additional axial stress (i.e. deviator stress) on the soil specimen produces shear stress on
a) horizontal plane only
b) vertical plane only
c) both horizontal and vertical planes
d) all planes except horizontal and vertical planes
Ans:d
99. In a triaxial compression test when drainage is allowed during the first stage (i. e. application of cell pressure) only and not during the second stage (i.e. application of deviator stress at constant cell pressure), the test is known as
a) consolidated drained test
b) consolidated undrained test
c) unconsolidated drained test
d) unconsolidated undrained test
Ans:b
100. During the first stage of triaxial test when the cell pressure is increased from 0.10 N/mm2 to 0.26 N/mm2, the pore water pressure increases from 0.07 N/mm2 to 0.15 “N/mm2. Skempton’s pore pressure parameter B is
a) 0.5
b) -0.5
c) 2.0
d) – 2.0
Ans:a