Test: Soil Compaction

QUESTION: 1

Match List-I (Equipment) with List-ll (Purpose) and select the correct answer using the codes given below the lists:
List-l
A. Sheep foot roller
B. Frog hammer
C. Vibratory roller
List-ll
1. To density cohesionless soils to relatively larger depths
2. To compact lumpy cohesive soil fills
3. To compact soils at corners and places which bigger rollers cannot access
4. To compact cohesionless soils of shallow depth

A.
A
B.
B
C.
C
D.
D

Solution:

QUESTION: 2

Match List-I (Roller type) with List-ll (Soil type) and select the correct answer using the codes given below the lists:
List-I
A. Pneumatic roller
B. Smooth wheeled roller
C. Sheep foot roller
D. Vibratory roller
List-II
1. Cohesive and granular soils
2. Plastic soils of moderate cohesion
3. Cohesionless soils
4. Silty soils of low plasticity

A.
A
B.
B
C.
C
D.
D

Solution:

QUESTION: 3

When the compactive effort is increased in a standard compaction test, the Optimum Moisture Content (OMC)

A.
Decreases
B.
Increases
C.
Does not change
D.
Is unpredictable

Solution:

The effect of increasing the amount of compactive effort is to increase the maximum dry density and to decrease the optimum water content.

QUESTION: 4

Compaction of soil is measured in terms of

A.
dry density
B.
specific gravity
C.
compressibility
D.
permeability

Solution:

QUESTION: 5

Vibro floatation techniques is best suited for densifying

A.
very loose sands below water table
B.
layered clays
C.
organic clays
D.
coarse sands and gravels

Solution:

QUESTION: 6

Given below are methods of compaction:
1. Vibration technique
2. Flooding the soil
3. Sheep foot roller
4. Tandem roller
5. Heavy weights dropped from a height
The methods suitable for cohesionless soils include

A.
1, 2 and 3
B.
2, 3 and 4
C.
1, 2 and 5
D.
3, 4 and 5

Solution:

Cohesionless soils can be compacted by vibration; flooding and dropping heavy weight from height. Kneading and tamping actions provided by sheeps foot roller and tandem roller are not effective for cohesionless soils.

QUESTION: 7

The unit weight of a soil at zero air voids depends on

A.
specific gravity
B.
water content
C.
unit weight of water
D.
All the above

Solution:

Unit weight at zero air void corresponds to dry density of soil.

∴ it depends on specific gravity, water content and unit weight of water.

QUESTION: 8

An increase in compactive effort will lead to which of the following?

A.
Decrease in both the Optimum Moisture Content (OMC) and maximum dry density.
B.
Decrease in the Optimum Moisture Content (OMC) and increase in the maximum dry density.
C.
Increase in the Optimum Moisture Content (OMC) and decreases in the maximum dry density.
D.
Increase in both the Optimum Moisture Content (OMC) and maximum dry density.

Solution:

For a given type of compaction, the higher the compactive effort, the higher the maximum dry unit weight and lower the optimum moisture content.

QUESTION: 9

Clayey soils are best compacted by

A.
sheep feet rollers
B.
vibratory rollers
C.
heavy drum rollers
D.
ramming and pneumatic tampering

Solution:

QUESTION: 10

Soil is compacted at which one of the following when a higher compactive effort produces highest increase in dry density?

A.
Optimum water content
B.
Dry side of the optimum moisture content
C.
Wet side of the optimum moisture content
D.
Saturation moisture content

Solution:

With increase in compactive effort, the optimum moisture content decrease and dry density increases. Thus soil is to be compacted on the dry side of the optimum moisture content of original (lower compactive effort) Proctor curve.