Question

Directions: The following items consists of two statements; one labelled as ' Assertion (A)' and the other as 'Reason (R)'. You are to examine these two statements carefully and select the answers to these items using the codes given below:

Assertion (A): The efficiency of the sheep foot roller depends on the weight of the roller and the number of 'feet' in contact with the ground at a time.

Reason (R): Sheep foot rollers are considered most suitable for compacting clayey soils.

• A. both A and R are true and R is the correct explanation of A
• B. both A and R are true but R is not a correct explanation of A
• C. A is true but R is false
• D. A is false but R is true

Answer 1

The correct option is B both A and R are true but R is not a correct explanation of A

The sheep-foot roller consists of a hollow drum with a large number of small projections (known as feet) on its surface. These projections penetrate the soil layers during the rolling operations and causes compaction.
The sheep-foot rollers are ideally suited for compaction of cohesive soils. The rollers compact the soil by a combination of tamping and kneading action. When the roller is passed for the first time, the projections penetrate the soil layer and the lower portion of the layer is compacted. In successive passes, compaction is obtained in the middle and the top portion of the layer. This continually rising effect of the compaction is called walking-out of the roller.