Author(s): Ram Krishna Regmi; Xuan Khanh Do; Kwansue Jung; Jaewon Kang
Linked Author(s): Kwansue Jung
Keywords: Dynamic programming; Slip surface; Spencer method; Slope stability; Safety factor
Abstract: In this paper, a dynamic programming method was employed, in conjunction with limit-equilibrium techniques, to determine the location of the non-circular critical slip surface in the analysis of a slope failure due to a rainfall event. The Spencer method of slope-stability analysis was incorporated into dynamic programming algorithm to predict the time of a slope failure and location of the slip surface. The limiting equilibrium consideration usually involves a process of minimization which identifies the critical slip surface, and its associated minimal safety factor. The most critical failure surface is the one along which failure is most likely to occur and for which the factor of safety is the lowest. This method was assessed through the data obtained from a laboratory flume experiment. The experiment was carried out under simulated rainfall in a 5.0m long, 0.3m wide and 0.5m deep flume, set at 27oslope. The dynamic programming search region was also contained the parts outside the actual slope so as to locate the points of entrance and exit of potential slip surface at any point on the surface of the model slope. The positive pore water pressure reduces the soil shear strength, so that the slip surface beneath the water table will be more unstable. Therefore, the boundary condition was provided to pass the slip surface, at least a small part, through the water table. The steepest slope of the slip surface was also assigned as a boundary condition. Pore-water pressure, moisture-content and surface-water head data obtained by a coupled twodimensional (2D) seepage-flow model and one-dimensional (1D) surface flow and erosion/deposition model were used to analyze the stability of the model slope. 1D sliding block model was used to analyze the motion of the failure mass. Furthermore, the stability of the model slope, during the movement of the sliding mass, was analyzed by updating the shape of the model slope according to the new position of the sliding mass.
Year: 2014