Slope Reliability Analysis Using Pseudo-dynamic Method with Monte Carlo Simulation and Multiple Slip Surfaces

Abstract:

The pseudo-dynamic Swedish circle method for seeking the factor of safety under critical initial phase is proposed to evaluate the stability for a given slip surface. A significant number of feasible slip surfaces are incorporated into the limit state function of slope reliability, and the Monte Carlo simulation method is combined to propose the seismic slope reliability analysis method based on the pseudo-dynamic Swedish circle method. The proposed methodology is applied to the stability analysis of a homogeneous slope, with a detailed investigation of the effects of shear wave velocity, horizontal seismic coefficient, and slip surface location on the critical initial phase (denoted by t_d) and factor of safety. It is found that with an increase in shear wave velocity, the factor of safety corresponding to the critical initial phase t_d gradually decreases and eventually converges to the result from the pseudo-static method. With an increase in the horizontal seismic coefficient, t_d remains constant, but the corresponding factor of safety tends to decrease. Moreover, under the same conditions, t_d also differs with the variation in the slip surface location. For homogeneous slopes, the t_d probability density function and failure probability obtained from the reliability analysis method based on the critical slip surface S_c (method 1) are essentially consistent with those derived from the analysis method based on a large number of feasible slip surfaces (method 2). However, since Method 1 fails to properly quantify the consequences of slope failure resulting from the variation in the slip surface location, it has the potential of underestimating the sliding volume. Method 2 is recommended for seismic slope reliability analysis.