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Match List-I (Equipment) with List-ll (Purpose) and select the correct answer using the codes given below the lists:
A. Sheep foot roller
B. Frog hammer
C. Vibratory roller
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
When the compactive effort is increased in a standard compaction test, the Optimum Moisture Content (OMC)
The effect of increasing the amount of compactive effort is to increase the maximum dry density and to decrease the optimum water content.
Compaction of soil is measured in terms of
Max dry density is achieved after the suitable compaction method at certain moisture content.
Vibro floatation techniques is best suited for densifying
Vibroflotation is most suitable for very loose sands submerged under water table. Efficiency of densification reduces with increase in silt and clay content and penetration rate reduces in case of dense sands with deep water tables.
Match List-I (Roller type) with List-ll (Soil type) and select the correct answer using the codes given below the lists:
A. Pneumatic roller
B. Smooth wheeled roller
C. Sheep foot roller
D. Vibratory roller
1. Cohesive and granular soils
2. Plastic soils of moderate cohesion
3. Cohesionless soils
4. Silty soils of low plasticity
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
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.
The unit weight of a soil at zero air voids depends on
Unit weight at zero air void corresponds to dry density of soil.
∴ it depends on specific gravity, water content and unit weight of water.
An increase in compactive effort will lead to which of the following?
For a given type of compaction, the higher the compactive effort, the higher the maximum dry unit weight and lower the optimum moisture content.
Clayey soils are best compacted by
Soil is compacted at which one of the following when a higher compactive effort produces highest increase in dry density?
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.