how does the water table affect pressure on a support of exc

how does the water table affect pressure on a support of excavation?(SOE)

Solution

Answer:-Effect of water table on support of excavation:-

Q_u = cN_c + yD_fN_qR_w1 +1/2 * yBN_yR_w2

Where

R_w1 =Reduction factor for water table above base level of the foundation

Y = y_sat

R_w2 = Reduction factor for water table below base level of the foundation.

Excess water pressure tends to lift soil particles.If upward pressure is high then soil behaves like fluid.This is called quick sand condition.

Water table pressure is harmful for support of excavation

Water pressure is also known as hydrostatic pressure

Pore water pressure= y_wh_w