ROTATION-TRANSLATION COMBINED MECHANISM FOR THE STABILITY ANALYSIS OF SLOPES WITH WEAK INTERLAYER UNDER RAINFALL CONDITION

摘要

Rain-induced failures are the most common cause of slope instability.This is particularly sensitive to the slopes with unsaturated weak layers.However,simple and rational evaluation methods for such a slope stability problem have not been proposed so far.In this paper,in order to obtain rigorous upper-bound solutions for the stability of slope with weak interlayer,a new failure mechanism consisting of rigid blocks undergoing impending rotational or translational movements is proposed to study the slope stability under rainfall condition and determine the safety factor combined with a strength reduction technique.Rainfall induced change of pore water pressure in slopes is analyzed by a transient seepage finite element analysis.The effects of pore-water pressure on the slope stability are then considered and incorporated into the limit analysis formulations.The proposed rotation-translation combined mechanism is finally verified by comparisons with displacement-based elasto-plasticity finite element method.The comparisons show that the proposed mechanism improves the efficiency of the previously-developed rigid block mechanisms to account for the presence of weak interlayer in the slopes and can be used as a simple evaluation method for the engineering design.