Seismic bearing capacity of shallow strip foundations in the vicinity of slopes using the lower bound finite element method

摘要

The seismic bearing capacity of shallow strip foundations in the vicinity of slopes was investigated by the use of the lower bound limit analysis in conjunction with the finite element method and the linear programming technique. The combination of the most probable failure modes including slope instability and ultimate bearing capacity makes the problem difficult to solve by conventional approximate methods such as the limit equilibrium, the bound theorems of the limit analysis, and the slip line methods since these are based on assumptions about either kinematically admissible failure mechanisms or statically admissible stress fields. The pseudo-static seismic loading scheme was adopted in the presence of both horizontal and vertical acceleration fields, and the soil-foundation interface was assumed perfectly rough. Parametric analyses were conducted to evaluate the most effective factors in the form of the dimensionless strength and geometry parameters. The results of the current study were found comparable with those in the literature, and the consistency of the results confirmed the robustness of the extended finite element lower bound formulation. It was shown that the normalized limit pressure is dramatically reduced as the earthquake acceleration coefficients increases, and that it increases with higher the soil strength parameters. Moreover, the threshold distance at which the influence of the slope diminishes was found to be a function of the soil strength parameters and the slope geometry. (C) 2019 Production and hosting by Elsevier B.V. on behalf of The Japanese Geotechnical Society.