GATE 2020 CE (CE1) – Question 33
A fully submerged infinite sandy slope has inclination 30°, saturated unit weight 18 kN/m³ and effective friction angle 38°. Water unit weight is 10 kN/m³ and seepage is parallel to the slope. Find safety factor against shear failure, to two decimals.
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Correct answer: .59 to .61
Explanation
With parallel seepage, $FS=(\gamma_{sat}-\gamma_w)\tan\phi^{\prime}/(\gamma_{sat}\tan\beta)$. Substitution gives $(8/18)\tan38^\circ/\tan30^\circ=0.6014$. Rounded, **0.60**.