GEO TERMS: SHEAR STRENGTH OF SOIL Flashcards
a triaxial shear test is preferred to direct shear test, because _____
A. it can be performed under all three drainage conditions with complete control
B. precise measurement of pore pressure and change in volume during test, is not possible
C. stress distribution on the failure plane, is non uniform
D. none of these
A. it can be performed under all three drainage conditions with complete control
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
D. decreases with decrease in normal stress
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 compression 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
D. unconfined compression test can be carried out on all types of soils
the angle of internal friction is least for _____
A. angular-grained loose sand
B. angular -grained dense sand
C. round-grained loose sand
D. clays
D. clays
for testing a saturated clay for shear strength, the test recommended is _____
A. direct shear test
B. triaxial compression test
C. unconfined compression test
D. all the above
C. unconfined compression test
the triaxial apparatus is usually used for _____
A. unconsolidated-undrained test
B. consolidated-undrained test
C. drained test
D. all the above tests
D. all the above tests
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
A. effective stress only
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
B. angle of internal friction
the angle between the directions of the failure and the major principal plane is equal to _____
A. 90° + effective angle of shearing resistance
B. 90° + half of the shearing resistance
C. 45° - half of the shearing resistance
D. 45° + half of the shearing resistance
D. 45° + half of the shearing resistance
the angle of internal friction of clay is usually _____
A. 0° to 5°
B. 5° to 20°
C. 20° to 30°
D. 30° to 45°
B. 5° to 20°
failure of a slope occurs only when total shear force is _____
A. equal to total shearing strength
B. greater than total shearing strength
C. less than total shearing strength
D. none of these
B. greater than total shearing strength
the angle of internal friction is maximum for _____
A. angular-grained loose sand
B. angular-grained dense sand
C. round-grained dense sand
D. round-grained loose sand
B. angular-grained dense sand
a direct shear test possesses the following disadvantage:
A. a relatively thin thickness of sample permits quick drainage
B. a relatively thin thickness of sample permits quick dissipation of pore pressure developed during the test
C. as the test progresses the area under shear, gradually changes
D. none of these
C. as the test progresses the area under shear, gradually changes
which one of the following statements is true for Mohr-Coulomb envelope?
A. Coulomb suggests that the relationship between shear
strength and normal stress, is adequately represented by the straight line
B. the generalized Mohr theory suggests that, though the shear stress depends on the normal stress, the relation is not linear
C. Coulomb and Mohr suggest that a definite relationship exists among the principal stress and the angle of internal friction
D. all the above
D. all the above
if drainage is permitted throughout the test, during the application of both normal, and shear stresses so that full consolidation occurs and no excess pore pressure is set up at any stage of the test is known as _____
A. quick test
B. drained test
C. consolidated undrained test
D. none of these
B. drained test
the shear resistance of a soil is constituted basically of the following component:
A. the frictional resistance to translocation between the
individual soil particles at their contact point
B. to the structural relation to displacement of the soil because of the interlocking of the particles
C. cohesion and adhesion between the surfaces of the soil particles
D. all the above
D. all the above
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 compactness increases
D. effective angle of internal friction is a complicated function of mineralogy and clay size content
A. effective cohesion of a soil can never have a negative value
the Mohr’s straight theory is based on the following fact:
A. material fails essentially by shear
B. ultimate strength of the material is determined by the stress in the plane of slip
C. failure criterion is independent of the intermediate principal stress
D. all the above
D. all the above
through a point in a loaded soil mass, there exists typical planes mutually orthogonal on which the stress is wholly normal and no shear stress acts if is
A. 1
B. 2
C. 3
D. 4
C. 3
pick up the correct statement from the following:
A. failure plane carries maximum shear stress
B. failure plane does not carry maximum shear stress
C. failure plane carries shear stress equal to maximum shear stress
D. none of these
B. failure plane does not carry maximum shear stress
on wetting, cohesive soils _____
A. loose permeability
B. gain shear strength
C. loose elasticity
D. decrease their shear strength
D. decrease their shear strength
pick up the correct statement from the following:
A. an unconfined compression test is a special case of triaxial compression test
B. an unconfined compression test is a special case of direct shear test
C. the confining pressure is maximum during an unconfined compression test
D. the cylindrical specimen of a soil is subjected to major principal stress till it fails due to shearing along the plane of the failure
A. an unconfined compression test is a special case of triaxial compression test
the direct shear test suffers from the following disadvantage:
A. drain condition cannot be controlled
B. pore water pressure cannot be measured
C. shear stress on the failure plane is not uniform
D. the area under the shear and vertical loads does not remain constant throughout the test
all are disadvantages of direct shear test
the length/diameter ratio of cylindrical specimens used in triaxial test is generally _____
A. 1
B. 1.5
C. 2
D. 2.5
C. 2
pick up the correct statement from the following:
A. isotropic consolidation of clay can be obtained in the triaxial apparatus under equal all-round pressure
B. if the present effective stress is the maximum to which the clay has ever been subjected, it is called normally consolidated clay
C. if the present effective stress in the past was more than present effective stress, it is called over-consolidated clay
D. all the above
D. all the above
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°
B. 90°
the internal molecular attraction of a soil, the cohesion _____
A. decreases as the moisture content increases
B. increases as the moisture content decreases
C. is more in well compacted clays
D. depends upon the external applied load
C. is more in well compacted clays
the shearing strength of a cohesionless soil depends upon _____
A. dry density
B. rate of loading
C. confining pressure
D. nature of loading
C. confining pressure
the area of cross-section “A” at failure or during any stage of Triaxial Compression Test and its initial length (L) and volume (V) are related by the equation _____
A. A = (V + △V) / (L - △L)
B. A = (V - △V) / (L + △L)
C. A = (V - △V) / (L - △L)
D. A = (V + △V) / (L + △L)
C. A = (V - △V) / (L - △L)
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°
B. 45°
the shear strength in undrained clay is due to _____
A. inter-granular friction
B. internal friction
C. cohesion
D. none of these
C. cohesion
the vane shear test is used for the in-situ determination of the undrained strength of the intact fully saturated
A. sands
B. clays
C. gravels
D. highly organic soils
B. clays
depending upon the properties of a material, the failure envelope may _____
A. be either straight or curved
B. pass through the origin of stress
C. intersect the shear stress axis
D. all the above
D. all the above
the equation 𝜏 = C + σ tanφ is given by _____
A. Rankine
B. Coulomb
C. Coleman
D. Mohr
B. Coulomb
through a point in a loaded soil, the principal stress is maximum on _____
A. minor principal plane
B. intermediate principal plane
C. major principal plane
D. none of these
C. major principal plane
in a deposit of normally consolidated clay
A. effective stress increases with depth but water content of soil and undrained 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
C. effective stress and undrained strength increase with depth but water content decreases with depth
cohesionless soil is _____
A. sand
B. Silt
C. clay
D. clay and silt
A. sand
the shear strength of a soil
A. increases with an increase in the normal stress
B. is proportional to the cohesion of the soil
C. is generally known as the strength of the soil
D. all the above
D. all the above
unconfined compressive strength test is _____
A. undrained test
B. drained test
C. consolidated undrained test
D. consolidated drained test
A. undrained test
for shear strength, triaxial shear test is suitable because _____
A. it can be performed under all three drainage conditions
B. precise measurement of the pore pressure and volume change during the test is possible
C. stress distribution on the failure plane is uniform
D. all the above
D. all the above
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
A. decreases
at liquid limit, all soils possess _____
A. same shear strength of small magnitude
B. same shear strength of large magnitude
C. different shear small magnitude
D. different shear large magnitude
A. same shear strength of small magnitude
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 planes
D. all planes except horizontal and vertical planes
D. all planes except horizontal and vertical planes
pick up the correct statement from the following:
A. the property of a soil that enables it to become stiff in a
relatively short time on standing is called thixotropy
B. the ratio of shear strength in natural state to the remoulded shear strength under undrained conditions is called degree of sensitivity
C. the difference between the undisturbed shear strength and remoulded shear strength is known remoulding loss
D. all the above
D. all the above
select the incorrect statement:
effective angle of shearing resistance
A. increases as the size of particles increases
B. increases as the soil gradation improves
C. is limited to a maximum value of 45°
D. is rarely more than 30° for fine grained soil
C. is limited to a maximum value of 45°
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
B. consolidated undrained test
when drainage is permitted under initially applied normal stress only and full primarily consolidation is allowed to take place, the test is known as _____
A. quick test
B. drained test
C. consolidated undrained test
D. none of these
C. consolidated undrained test
the maximum shear stress occurs on the filament which makes an angle with the horizontal plane equal to _____
A. 30°
B. 45°
C. 60°
D. 90°
B. 45°
