Abstract: In view of the existing unreasonable assumption on interslice shear forces involved in the horizontal slice limit equilibrium method for active earth pressure on rigid retaining walls, a mobilized coefficient of the interslice shear strength of the soil is proposed and its development mode is assumed to be 3 types of function including sine, linear, and hyperbolic patterns. A series of statistical values of the coefficient is given based on a great number of model test and in-situ observed results of the earth pressure. Further, static and seismic active earth pressure on rigid retaining walls can be determined using the horizontal slice method and pseudo-static approach with rationally considering the shear forces on interslice. Planar and log-spiral modes of potential slip surfaces of the retained soil are involved in the proposed method, which takes into account wall configuration, soil properties as well as external loads. It is found that the mobilized coefficient is not usually zero in the condition that wall-soil friction angle is equal to soil internal frictional angle or half of it, and the coefficient is greatly influenced by the wall-soil friction angle. The hyperbolic profile of the mobilized coefficient for wall translation and the sine mode for wall rotation about its heel are recommended because that the introduction of the mobilized coefficient can make the application points of the resultant of the active earth pressure relatively approach to the measured values. Internal friction angle of the soil, wall-soil cohesion, and vertical seismic factor have little effect on the application point of the resultant, while the soil cohesion, dip angle of the soil top surface, wall back inclination, wall-soil friction angle, and horizontal seismic factor have a greater influence. Some examples show that calculation results including the resultant and its application point of the active earth pressure using the proposed method are in good agreement with those monitored, and the maximum errors are less than about 10% and 7%, respectively.

Key words: rigid retaining walls, active earth pressure, horizontal slice method, interslice shear forces, distribution mode