基于有限元的边坡稳定可靠度改进一次二阶矩法研究

An AFOSM-FEM-based Approach for Evaluating the Reliability of Slope Stability

为研究岩质边坡岩体参数变化时的稳定性,提出一种基于有限元的边坡稳定可靠度改进一次二阶矩法。首先,针对边坡工程中广泛存在的隐式极限状态函数可靠性问题,定义极限状态函数为滑体极限状态下抗滑力与下滑力的差值,考虑黏聚力及内摩擦角作为随机变量并且服从独立正态分布,求出极限状态方程中随机变量的偏导数;然后,根据改进一次二阶矩法编写了求解边坡失稳概率和可靠指标的计算程序;最后,通过算例验证了所提方法的适用性。某库岸边坡可靠性分析结果表明,该方法具有计算流程简单、便于开展、节省机时、计算精度高的优点。

To study the stability of slope under the condition of material parameters variation,a reliability analysis approach based on finite element method(FEM)and advanced first-order second-moment method(AFOSM)is proposed.Firstly,considering the reliability problem of implicit limit state function widely existing in slope engineering,the limit state function is defined as the difference between anti-sliding force and sliding force at critical stress state of sliding body,and considering cohesion and friction angle as random variables subjected to independent normal distribution,the partial derivatives of random variables in the limit state equation are derived.Then,based on advanced first-order second-moment method,the program solving the probability and reliability index of slope failure is written.Finally,an example is given to verify the application of the proposed method.The reliability analysis results of the bank slope of a reservoir show that the method has the advantages of simple calculation process,easy to carry out,time-saving and high-precision.