关键词: 破裂面, 刚性挡墙, 无粘性土, 变分法, 解析解

Abstract: In the classical Coulomb’s earth pressure theory, the failure surface in the backfilled cohesionless soil behind rigid retaining wall in slope engineering is assumed a plane. However, it has been proved by a number of laboratory and field tests that this failure surface is actually a curved surface. In this paper, based on the vertical differential element method and the variational principle with moveable boundary, a quadratic ordinary differential equation of the first order about the failure surface is deduced. Three cases of the equation are discussed: 1) without lateral shear force at the interface between two elements, and the back of the retaining wall is frictionless, the failure surface is a plane; 2) lateral shear force is a constant, and the back of the wall is rough, the failure surface is also a plane, the two cases above mentioned are identical to Coulomb’s theory; 3) lateral shear force increases linearly from the tip to the toe, the failure surface is a curved surface. Results show that the proposed approach can predict right failure pattern of the backfilled cohesionless soil, which is in good agreement with that of the laboratory and field tests.

Key words: failure surface, rigid retaining wall, cohesionless soil, variational principle, analytical solution