Mathematical Analysis of Lateral Earth Pressure Distribution on Rigid Retaining Walls

The shape of slip surface of the wedge creating lateral thrust on rigid retaining walls plays an important role in the magnitude، distribution، and height of point of application of lateral thrust. Considering the shape of slip surface as linear، circular، logarithmic spiral، or a combination of them has been used in the literature. In the Coulomb lateral earth pressure method، a linear distribution of soil pressure on retaining walls is tentatively assumed and thus the point of application of total thrust is placed at one third of the wall height from the wall bottom. However، some experimental studies have revealed non-linear distribution of lateral earth pressures and that the point of application of resultant thrust is placed upper than one third of the wall height. In the present study، a plasticity equation is used to determine the reaction of the stable soil on cohesionless backfill supported by a retaining wall using an empirical equation derived from experiments performed in the field by others. A new analytical solution for determining the total resultant thrust on the wall is introduced and the distribution of pressures and the point of application of total thrust are computed. The results have been compared with some analytical methods، experimental data، and also with available data reported from field، demonstrating the accuracy and capability of the developed method. The results show that the distribution of the active lateral earth pressure is nonlinear and the point of application of total thrust is located about 0. 42H from the wall bottom (H=wall height). In addition، the application point of total thrust is nonlinear function of soil-soil، wall-backfill soil friction angels and the height of the wall