Soil Mechanics and Foundation Engineering (Part-2) (General Engineering) (SSC JE)

Total Questions: 50

31. A clay has unconfined compressive strength of 240 kN/sq.m in undisturbed state. The clay was then remolded and the unconfined compressive strength was found to be 60 kN/sq.m. The sensitivity of this clay is : [RRB S.S.E. (Secunderabad) 01.09.2015 (Shift-I) ]

Correct Answer: (d) 4.00
Solution:

32. The numerical difference between the plastic limit and shrinkage limit of a remoulded sample is called as : [RRB S.S.E. 03.09.2015 (Shift-II)]

Correct Answer: (b) Shrinkage index
Solution:

33. The process in which a stress applied to a soil causes densification as air is displaced from the pores between the soil grains is called as : [RRB S.S.E. 03.09.2015 (Shift-II)]

Correct Answer: (c) Compaction
Solution:

Compaction– In general is the densification of soil by removal of air, which requires mechanical energy. Simplistically, compaction may be defined as the process in which soil particles are forced closer together with the result and reduction in air voids.

34. The imaginary surface connecting points to which water would rise in tightly cased wells from a given point in an aquifer is called as : [RRB S.S.E. 03.09.2015 (Shift-II)]

Correct Answer: (c) Potentiometric surface
Solution:

A potentiometric surface, also known as piezometric surface is the imaginary plane where a given reservoir of fluid will equalize out if allowed to flow. Potentiometric surface is an imaginary surface that defines the level to which water in a confined aquifer would rise when it completely pierced with walls.

35. Which of the following is not applicable to pile foundations? [RRB S.S.E. 03.09.2015 (Shift-II)]

Correct Answer: (d) Piles do not anchor structures subjected to hydrostatic uplift
Solution:

Necessity of pile foundation–
(i) When the strata at as just the ground surface is highly compressible and very weak to support the load transmitted by the structure.
(ii) Pile foundation are used to resist a horizontal force.
(iii) Pile are required when the soil condition are such that a wash out, erosion or scour of soil may occur from underneath of a shallow foundation.
• Anchor pile provided resistance against Hz pull.

36. An earth retention and excavation support technique that retains soil, using steel sheet sections with interlocking edges is : [RRB S.S.E. 01.09.2015 (Shift-II) ]

Correct Answer: (c) Sheet piling
Solution:

Sheet piles are sections of sheet materials with interlocking edges that are driven into the ground to provide earth retention and excavation support. These are usually made of steel or timber. However some times cement concrete sheet piles are also used.

37. The dry density of which sample is expected to be highest– [RRB JE 16.09.2015 (Shift-III) ]

Correct Answer: (d) Dense sand
Solution:

38. The liquid and plastic limit exist in– [RRB JE 16.09.2015 (Shift-III) ]

Correct Answer: (d) Clay soils
Solution:

• Liquid and plastic limit exist in clay.
• The become plastic only when it has clay minerals.

39. The property of soil mass pertaining to its suscentibility to decrease in volume under pressure is known as : [RRB S.S.E. 01.09.2015 (Shift-III) ]

Correct Answer: (c) compressibility
Solution:

Compressibility– Compressibility of soil is defined as gradual decreases in volume of soil.
• The coefficient of compressibility decreases with increase in effective stress.
Note– Void ratio v/s effective stress (Normal consolidation curve or Normal compression curve)

40. According to Darcy's law, for laminar flow in a saturated soil, the rate of flow is proportional to the : [RRB S.S.E. 01.09.2015 (Shift-III) ]

Correct Answer: (b) Hydraulic gradient
Solution:

Darcy's law– In one dimensional flows, for ground water movement state that the velocity is proportional the hydraulic gradient.