This question was previously asked in

CGPSC Civil Official Paper 3 (Held on Feb 2018 - Shift 2)

Option 2 : 1

ST 1: Solid Mechanics

1282

20 Questions
40 Marks
20 Mins

__Concept:__

Critical hydraulic gradient (icr): The quick condition occurs at a critical upward hydraulic gradient ic, when the seepage force just balances the buoyant weight of an element of soil. The critical hydraulic gradient is typically around 1.0 for many soils.

\({i_{cr}} = \frac{{{G_s} - 1}}{{1 + e}} \)

At the critical conditions, the effective stress is equal to zero.

__Calculation:__

Given, e = 0.67, Gs = 2.67

\(∴ {i_{cr}} = \frac{{{G_s} - 1}}{{1 + e}} = \frac{{2.67 - 1}}{{1 + 0.67}} =1\)

**∴ Critical hydraulic gradient is 1**