WORLD FOR CIVIL

Lateral Pressures In Cohesionless Soils

For walls that retain cohesionless soils and are free to move an appreciable amount, the total thrust from the soil is

P = [½ g H²cosi[cos i - {(cos i )² – (cosf) ² }^1/2]/ [cos i +{(cos i )² – (cosf)²}^1/2

When the surface behind the wall is level, the thrust is

P=0.5gH²K_A

where

K_A=[tan(45-f/2]²

The thrust is applied at a point H /3 above the bottom of the wall, and the pressure distribution is triangular, with the maximum pressure of 2P / H occurring at the bottom of the wall.

For walls that retain cohesionless soils and are free to move only a slight amount, the total thrust is 1.12P, where P is as given earlier. The thrust is applied at the midpoint of the wall, and the pressure distribution is trapezoidal, with the maximum pressure of 1.4P / H extending over the middle six-tenth of the height of the wall.

For walls that retain cohesionless soils and are completely restrained (very rare), the total thrust from the soil is

P = [½ g H²cosi[cos i + {(cos i )² – (cosf) ² }^1/2]/ [cos i -{(cos i )² – (cosf)²}^1/2

When the surface behind the wall is level, the thrust is

P=0.5gH²K_P

where

K_P=[tan(45-f/2]²

The thrust is applied at a point H /3 above the bottom of the wall, and the pressure distribution is triangular, with the maximum pressure of 2P / H occurring at the bottom of the wall.