Abstract: To determine the distribution of the active earth pressure of the cohesionless soil under the rigid retaining wall rotating around the base (i.e., RB) mode, the discrete element simulations concerning different post-fill widths were carried out. The simulation results show that the active earth pressure distribution in the RB mode is different from the parabolic distribution of the active earth pressure in the translation (T) mode. When the soil behind the wall is in an active limit state, multiple parallel slip lines are formed inside the soil. An oblique differential element method based on slicing of slip line is proposed based on the numerical results. Based on the proposed method, the soil behind the wall is divided into several oblique differential elements, and the theoretical formula of active earth pressure under RB mode is derived according to the static equilibrium condition. In the case of infinite soils, the theoretical formula is consistent with the Coulomb's active earth pressure formula of triangular distribution. In the case of finite soils, the active earth pressure is piecewise linear distribution along with the depth. In the case of wall soil without friction, the theoretical formula will degenerate into Rankine's active earth pressure formula. Finally, the rationality and effectiveness of the theoretical formula are verified by comparing with the results of discrete element simulation, previous theoretical methods, and model tests.

Key words: discrete element simulation, active earth pressure, finite soils, rotating about the base, oblique differential element method, cohesionless soil