Soil Mechanics and Foundation Engineering (General Engineering) (SSC JE)

Total Questions: 50

31. A sample of clay and a sample of sand have the same specific gravity and void ratio. Their permeabilities would differ because [BPSC AE (Civil) 30.03.2019 ]

Correct Answer: (d) the size ranges of their voids would be different
Solution:

Permeability–Permeability is defined as the property of a porous material that permits the passage or seepage of water through its interconnecting voids. Factors affecting the permeability of soil–
1. Grain size
2. Properties of the pore fluid
3. Voids ratio of the soil etc.
The clay have small size of particle and sand have medium size of soil particle, small particle retain more water then medium particle. So sand is more permeable then clay.

32. In a saturated clay layer undergoing consolidation with single drainage at its top, the pore water pressure would be the maximum at its [BPSC AE (Civil) 30.03.2019 ]

Correct Answer: (c) bottom
Solution:

There are two type of drainage conditions–
1. A single drained condition, that is only the top of upper layer is drained.
2. A double-drained condition, that is both top and bottom of layers are freely drained.

Pore water pressure– Pore water pressure is the pressure of groundwater held between soil or rocks in the gaps between particles. It is affected by the soil type, water flow conditions and level of the water table.

33. A saturated clay stratum of thickness 10m, bounded on top and bottom by medium coarse sand layers, has a coefficient of consolidation of 0.002 cm²/s. If this stratum is subjected to loading, it is likely that it would undergo 50% of its primary consolidation in [BPSC AE (Civil) 30.03.2019 ]

Correct Answer: (c) 284 days
Solution:


34. Which of the following parameters can be used to estimate the angle of internal friction of sandy soil? [BPSC AE (Civil) 30.03.2019 / RRB JE 30.08.2015 (Shift-III) ]

Correct Answer: (d) Density index
Solution:

35. A cantilever sheet pile derives its stability from [BPSC AE (Civil) 30.03.2019 ]

Correct Answer: (a) lateral resistance of soil
Solution:

Cantilever sheet pile wall–The cantilever sheet pile drives its stability solely from lateral resistance of the soil in which the sheet pile is driven. The sheet pile is driven to a suitable depth below the dredge line. The sheet pile acts as a cantilever.

36. Deflection of a sheet pile in a braced cut [BPSC AE (Civil) 30.03.2019 ]

Correct Answer: (a) increases from top to bottom
Solution:

Braced excavations– Excavation of soils to significant depth are laterally supported temporarily by braced sheeting and permanently by retaining walls. Braced sheeting basically consists of a sheet piling to support the sides of the excavation with stability being maintained by means of struts across the excavation.

37. The time t required for attaining a certain degree of consolidation of a clay layer is proportional to [BPSC AE (Civil) 30.03.2019 ]

Correct Answer: (b)
Solution:

Time rate of consolidation–The rate at which the consolidation occurs depends mainly on the permeability of the soil and the length of the drainage path.
• Time rate of consolidation can be calculated using the following equation

38. The static cone penetration test and a standard penetration test are performed on a soil at a certain depth. The value of static cone penetration test is 8 Mpa and the N value is 20. The soil met with at that depth is [BPSC AE (Civil) 30.03.2019 ]

Correct Answer: (a) sandy silt
Solution:

The static cone penetration test also known as cone penetration test (CPT) is a method of geotechnical investigation for testing bearing capacity and penetration resistance of soil.
Solve–

39. If the specific yield of a particular sand is 30% and its porosity is 50%, then the specific retention of the sand will be [BPSC AE (Civil) 14.10.2022 ]

Correct Answer: (d) 20%
Solution:

40. During seepage through an earth mass, the direction of seepage is [BPSC AE (Civil) 30.03.2019 ]

Correct Answer: (c) perpendicular to the equipotential
Solution:

Equipotential lines–A line along which the potential head at all points is equal.
Flow net–Graphical construction used to calculate groundwater flow through soil comprised of flow lines and equipotential lines.
Flow line–A line along which a water particle moves through a permeable soil medium.
Seepage–It is defined as the flow of a fluid, usually water through a soil under a hydraulic gradient. The direction of seepage is always perpendicular to equipotential line.