Question

Quick sand condition occurs when

• A. The void ratio of the soil becomes \(1.0\)
• B. The upward seepage pressure in soil becomes zero
• C. The upward seepage pressure in soil becomes equal to the saturated unit weight of soil
• D. The upward seepage pressure in soil becomes equal to the submerged unit weight of the soil

Hint:

Quick sand condition occurs when \[ \boxed{ i=i_c \quad\Rightarrow\quad \text{Seepage force}=\text{Submerged weight of soil}. } \]

Answer 1

The Correct Option is D

Step 1: Recall the quick sand condition. Quick sand (boiling) condition occurs when the upward seepage force becomes equal to the submerged weight of the soil.

Step 2: State the condition. At the critical hydraulic gradient, \[ \boxed{ \text{Upward seepage force} = \text{Submerged weight of soil}. } \] Hence, \[ \boxed{(D)} \] is the correct answer.