GATE 2026 CE (CE2) – Question 56
For a clayey soil stratum, the time required for degree of consolidation from 25 % to 50 % is 30 days.
The total time (in days) required for 90 % degree of consolidation of the same soil stratum is ______ (*rounded off to the nearest integer*).
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Correct answer: 173
Explanation
Time is proportional to the time factor, and for $U < 60\%$ the time factor is $T_v = \frac{\pi}{4}U^2$. So $T_{25} = 0.0491$ and $T_{50} = 0.1963$, a difference of 0.1473 for the 30 days. For $U = 90\%$ the time factor is $T_{90} = 0.848$. So $t_{90} = 30 \times \frac{0.848}{0.1473} = 172.8$ days, which is 173 days.