Active Earth Pressure - The Coulomb Theory
Active earth pressure is given by the following formula:
where: | σz | - | vertical geostatic stress |
cef | - | effective cohesion of the soil | |
Ka | - | coefficient of active earth pressure | |
Kac | - | coefficient of active earth pressure due to cohesion |
The coefficient of active earth pressure Ka is given by:
The coefficient of active earth pressure Kac is given by:
for: 
for: 
where: | φ | - | angle of internal friction of soil |
δ | - | ||
β | - | slope inclination | |
α | - | back face inclination of the structure |
Horizontal and vertical components of the active earth pressure become:
where: | σa | - | active earth pressure |
δ | - | ||
α | - | back face inclination of the structure |