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A masonry dam is founded on previous sand having porosity equal to 45% and specific gravity of sand particles is 2.65. For a desired factor of safety of 3 against sand boiling, the maximum permissible upward gradient will be
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- 0.225
- 0.302
- 1.0
- None of these
Correct Option: B
Hydraulic gradient,
| ic = | 1 + e |
= (G – 1) (1 – x)
= (2.65 – 1) (1 – 0.45) = 0.9075
Factor of safety,
| F.S = = | permissible upward gradient |
| 3 = | ipu |
∴ permissible upward gradient = 0.3025
