边坡稳定分析有限元强度折减法失稳判据探讨

有限元强度折减法目前广泛应用于复杂条件下边坡稳定安全度的求解,其边坡失稳判据主要有有限元计算不收敛、位移拐点及塑性区贯通等.相应存在的问题有:收敛性受非线性求解方法制约、位移曲线的拐点有时并不明确、在滑动面未知的情况下塑性区贯通判据难以准确把握临界点等.针对一经典边坡,讨论不同迭代算法的影响,提出边坡位移曲线的双拐点概念,从另一角度分析各判据,根据其特点建议联合采用位移出现拐点与塑性区全部贯通作为边坡失稳判据.

Discussion on Slope Failure Criteria for Evaluating Slope Stability Based on Shear Strength Reduction Finite Element Method

The shear strength reduction finite element method is widely employed to analyze slope stability especially under complicated conditions;currently,there are mainly three kinds of slope failure criteria： the convergence of numerical computations;the inflection point of the displacement;connectivity of plastic zone;etc.However,the convergence of numerical computations is limited by nonlinear solutions;the inflection point of the displacement is not always clear;moreover,the critical point with unknown sliding surface is not accurate using the criterion of connectivity of plastic zone.An example slope is analyzed by different iteration methods based on the shear strength reduction finite element method;it is shown that the computed result has great relationship with the iteration methods and convergence tolorence;two inflection points may occurred in the displacement curve which denpend on the initial state of the slope.As a result,the combination of the inflection point and the plastic zone is suggested as the proper slope failure criterion.