Question

Consider the following statements:

1. A recovery ratio of less than 1 implies that the soil has compressed.

2. A recovery ratio of greater than 1 implies that the soil has swelled.

3. A recovery ratio of less than 1 implies that the soil has swelled.

4. A recovery ratio of greater than 1 implies that the soil has compressed.

Which of these statements is/are correct?

1. 1 and 2
2. 1 only
3. 3 and 4
4. 4 only

Answer 1

Correct Answer - Option 1 : 1 and 2

Explanation:

(i) The sample disturbance depends on the design features of a sampler (cutting edge, inside wall friction and non-return valve) and the method of sampling.

(ii) Disturbance can be measure in terms recovery ratio, which is

\({L_r} = \frac{{{\mathop{\rm Re}\nolimits} {\mathop{\rm cov}} ered\ length\ of\ sample}}{{penetration\ length\ of\ sample}}\)

If, L_r = 1, Good recovery

L_r  > 1, Sample of swelled

L_r < 1, Sample of shrunk or compressed