- cohesive strength(c) -of the retained material wich can be explained as the interior own strength(shear strength)of a material besides his own weight;
- unit weight(y)-of a material wich is defined as the weight per unit volume of a material(G/V);
- angle of friction((φ-phi)-wich is the maximum angle of a certain material that will remain stable and will not begin sliding.
Also in order to proper design a retaining wall we need to take in consideration the following earth pressures categories:
- active earth pressure(Ka)
- passive earth pressure(Kp)
- earth pressure at rest(Ko)
- influence of loading
- influence of water pressure
- influence of broken terrain
- friction between soil and back of structure
- wall adhesion
- influence of earth wedge at cantilever jumps
- influence of earthquake
Recommended values for typical calculations:
- ACTIVE AND PASSIVE PRESSURE
The active state(Ka) occurs when a soil mass is allowed to relax or move outward to the point of reaching the limiting strength of the soil; that is, he soil is at the failure condition in extension. Thus it is the minimum lateral soil pressure that may be exerted. Conversely, the passive state(Kp) occurs when a soil mass is externally forced to the limiting strength (that is, failure) of the soil in compression. It is the maximum lateral soil pressure that may be exerted. Thus active and passive pressures define the minimum and maximum possible pressures respectively that may be exerted in a horizontal plane.
- Rankine theory
- ; Ka=active coeficient for earth type
- ; Kp=passive coeficient for earth type
- Coulomb theory
- For an automated calculation of active,passive and at-rest pressures you can try a free application that you can acces by clicking here .