If the backfill surface and/or the internal face of the wall are irregularly shaped or if there are point or line loads acting on the backfill, graphical methods are used for the calculation of earth pressures. One of the common methods is the Culmann Method (1966). Every graphical method can be adjusted so that it can be applied using a computer.
The Culmann graphical method is presented below.
The Coulomb theory can be applied in cases of cohesive soils. In this case, a assumption need to be made regarding the coefficient of friction, Cw, between wall and soil. Also it is accepted that in the case of active pressures, vertical fractures are developed at the top of the wall, due to the tensile forces that are generated at depth:
If the crack is filled with water, then the hydrostatic pressure creates an additional pressure on the exemplified soil-wall prism.
Gravity Walls The active earth pressures on the w...