Question

The 3m high vertical earth retaining wall retains a dry grannular backfill with angle of internal friction of ${30}^{\circ }$ and unit weight $20KN/m^3$. If the wall is prevented from yielding (no movement) the total horizontal thrust (in KN per unit length) on the wall is

• A. 0
• B. 30
• C. 45
• D. 270

Answer 1

The correct option is C 45


As wall does not move, so wall is at rest.

Coeffcient of earth pressure at rest $k_0=1-sin\varphi$

$=1-sin{30}^{\circ }=0.5$

Earth Pressure Distribution :
$k_o\gamma H=30kN/m^2$

$ResultantThrust\left(P_0\right)=\frac{1}{2}\left(k_0\gamma H\right)\left(H\right)$
$=\frac{1}{2}\times 30\times 3$
= 45 kN/m