Active earth pressure of narrow cohesive backfill on rigid retaining wall of rotation about the bottom

Abstract

Retaining wall construction often encounters narrow cohesive backfill and the traditional theories are no longer suitable. Hence, analytical solutions for active earth pressure of narrow cohesive backfill on a rigid retaining wall rotating about the bottom are proposed in this paper. The principle stress rotation caused by interface friction is also included. Through a typical FEM analysis and analytical derivation, the multi-segmented failure surface composed of a logarithmic spiral curve in the lower part and a tangent line in the upper part is quantitatively determined. According to the aspect ratio of the narrow backfill, three basic failure models of the narrow cohesive backfill are found together with three types of differential elements. A program is coded to automatically identify these three failure models to quickly obtain the distribution, the resultant and the application point of the active earth pressure. The proposed analytical solutions are then verified through a two-step procedure of elaborate comparisons with the FEM results and good agreements are observed. Subsequently, a parametric investigation indicates the active earth pressure is positively correlated to the aspect ratio and slope inclination angle, while is negatively correlated to the soil cohesion and interface friction.