Studies on accelerating convergence method in nonlinear stochastic finite element analysis of slope stability

There is much iteration in the stochastic finite element reliability analysis of slope stability which based on the stress analysis of sliding surface,such as the iteration circulation of reliability indices,the iteration circulation of nonlinear stochastic finite element analysis and the searching circulation of the minimum reliability indices of all possible sliding surfaces.Therefore,it is very important to improve the solving method of nonlinear equations and to decrease the number of iteration.The nonlinear stochastic finite element accelerating formula was derived based on the modified Aitken formula and the method of incremental tangent stiffness and was applied to the reliability analysis of a slope.The method of reliability analysis was a limit step length iteration method(LSLIM).It was demonstrated by a two-layer slope that the proposed accelerating method was feasible.It could reduce the number of iteration and improve the running speed greatly.As to the reliability indices,it was shown that if there existed large differences between the values of reliability indices obtained from the mean first order reliability method(MFORM) and LSLIM,there should be great differences in the locations of these corresponding sliding surfaces,and vise visa.