Soil Mechanics MCQ - Determination of in-situ Density

1. Shrinking limit can be found out using alternate method, if __________
a) The specific gravity of soil is known
b) Dry volume of soil is known
c) Water content in the soil is known
d) Dry density of soil is known

Answer: a
Explanation: Alternatively, shrinking limit can be found out if the specific gravity G of the soil grains is known.

2. The filed density of a natural soil deposit cannot be determined by_____ method.
a) sand replacement
b) oven-dry
c) core cutter
d) water displacement

Answer: b
Explanation: The methods for determining field density are:
sand replacement method
core cutter method
water displacement method
rubber balloon method
The oven-dry method is used for the determination of water content.

3. Arrange the following to obtain the correct procedure of sand replacement method.
I. Measurement of soil density
II. Determination of water content and dry density
III. Calibration of the cylinder
a) (I), (II), (III)
b) (III), (II), (I)
c) (III), (I), (II)
d) (I), (III), (II)

Answer: c
Explanation: In sand replacement method, first the density of the sand used is found by calibrating the cylinder. The soil density is found with respect to sand density. Then the soil sample is taken for water content determination.

4. For calibration of cylinder _______ is used.
a) Gravel
b) Sand
c) Soil
d) Silt

Answer: b
Explanation: For calibration of cylinder, weight of the sand required to fill the pouring cone of cylinder is needed. Uniformly graded, dry, clean sand passing a 600micron sieve and retained on 300micron IS sieve is used.

5. Arrange the following to obtain the correct procedure of soil density by sand replacement method.
I. Cylinder is placed over a tray
II. Tray with central hoe is placed in ground
III. Test hole is dug
IV. The cylinder valve is opened
a) (I), (II), (III), (IV)
b) (II), (III), (I), (IV)
c) (I), (III), (II), (IV)
d) (II), (III), (IV), (I)

Answer: b
Explanation: First the tray with central hoe is placed in ground then a test hole is dug equal to depth of calibrating container. The cylinder is placed over the tray and the valve is opened for sand to run and fill the test hole.

6. In sand replacement method, if the mass of sand filling the calibrating container is 1450g and volume of calibrating container is 1000cm3, then its buk density is_______ g/cm3.
a) 1450
b) 1.45
c) 45
d) 17

Answer: b
Explanation: Given,
Mass of sand filling the calibrating container M’=450g
Volume of calibrating container V=1000cm3
∴Buk density ρ=M’/V=1450/1000
ρ=1.45 g/cm3.

7. The IS code for determination of dry density by sand replacement method is ________
a) IS 456:2000
b) IS 2720-1975/88 (Part XXIX)
c) IS 2720-1974/88 (Part XXVIII)
d) IS 800

Answer: c
Explanation: IS 456:2000 is used for design of reinforced structures. IS 2720-1975/88 (Part XXIX) is used for determination of dry density core cutter method. IS 800 is used for design of steel structures.

8. The inner diameter of the core cutter is_____ cm.
a) 5
b) 10
c) 13
d) 15

Answer: b
Explanation: The core cutter consists of steel cutter with 10cm internal diameter and 13cm external diameter. The cutter consists of hardened edges.

9. The principle of submerged mass density method is_______
a) Equilibrium of floating bodies
b) Stroke’s law
c) Archimedes’ principle
d) Darcy’s law

Answer: c
Explanation: The submerged mass density is based on Archimedes’ principle that when a body is submerged in water, the reduction in its mass is equal to the mass of volume of water displaced.

10. The plasticity of clay depends on which of the following?
a) The nature of clay minerals present
b) Volume of clay present
c) All of the mentioned
d) None of the mentioned

Answer: a
Explanation: The plasticity depends on
i) The nature of clay minerals present
ii) amounts of clay minerals present.