基于PEM--JFEM方法的节理岩质边坡稳定性评价

Jointed rock slope stability evaluation based on PEM- JFEM method

以赞比亚一露天铜矿南帮边坡(矿体下盘)为研究对象,将Rosenbluth点估计方法与节理有限元方法相结合应用于该节理发育的岩质边坡稳定性评价中.建立以边坡岩体材料强度参数(内摩擦角和黏聚力)为输入变量,安全系数为输出变量的概率模型,点估计状态函数的求解过程引入节理有限元方法.通过现场节理及结构面调查,建立边坡节理有限元模型求解边坡安全系数,得到基于安全系数的边坡变形破坏概率统计指标,对边坡稳定性进行了概率分析,分析结果与现场失稳情况一致.该方法既考虑了岩体材料参数在赋值过程中实际存在的不确定性,同时也考虑了节理岩质边坡的节理属性,充分体现了岩层接触作用的非线性关系,使得对节理岩质边坡的稳定性评价更加合理.

With the south slope（ footwall） of an open pit in Zambia as a research subject,the Rosenbluth point estimation method（ PEM） coupled with the jointed finite element method（ JFEM） was applied to this jointed rock slope stability evaluation. A probability model was established,which puts the mean and standard deviation of rock material strength parameters（ friction angle and cohesive） as input variables and the safety factors as output variables,and the point estimation state functions were solved by the jointed finite element method. According to on-site joints and structural surface surveys,a jointed slope model was built to solve the safety factors,and then the probability distribution of the safety factors was obtained. The results of probability analysis are consistent with the instability situation on site. Since the uncertainty of rock materials and the properties of rock joints are taken into account,this method fully reflects the role of the non-linear relationship among rock layers and makes the rock slope stability estimation more reasonable.