边坡稳定性的研究，一直是岩土工程界广为关注的课题。白音华三号露天煤矿正处于首采区表土剥离阶段，由非工作帮及外排土场组成的复合边坡是否稳定，成为该矿目前急需解决的问题。本文以FLAC3D数值模拟为基础，将数值模拟、极限平衡法和可靠度分析方法整合应用，以“应力—应变力学行为”、“稳定系数”和“可靠度”为指标，综合分析了该复合边坡的稳定性。 本文根据《岩土工程勘察规范》(GB50021-2001)、霍克-布朗经验强度准则和类似工程经验，确定了边坡岩体物理力学性质指标值，并认为该复合边坡岩体类型属于软—半坚硬岩体。通过工程地质分析定性地认为，岩性、结构面、地下水、边坡形态及外载对该边坡稳定性均存在重要影响；通过多因素敏感性分析认为，内摩擦角、重度、粘聚力和地下水位等因素对该边坡稳定参数的敏感性依次变小。 本文在分析边坡稳定性时，首先利用Surfer、ANSYS等软件建立了FLAC3D数值模型，采用FLAC3D数值模拟及强度折减法，分析了边坡在静力平衡条件下和流固耦合条件下的应力—应变力学行为，并确定了潜在滑面的位置和形态。其次，借助“理正边坡稳定分析”软件，采用极限平衡法，验证了数值模拟所确定的潜在滑面，并采用简化Bishop法和Janbu法计算了最危险滑面及指定滑面的稳定系数。最后，以极限平衡法计算的稳定系数为指标，根据均值一次二阶矩法的基本原理，以数值模拟确定的潜在滑面为指定滑面，计算了边坡整体及局部的可靠度指标和破坏概率。通过分析认为，采用不同方法、不同评价指标从不同侧面均说明了该复合边坡在目前性状下整体处于稳定状态，但外排土场边坡等局部处于不可接受的风险水平；该复合边坡呈现圆弧形、平面剪切及卸荷破坏等复杂的破坏模式。研究成果与现场实际情况吻合较好。 本文研究说明了以数值模拟为基础，将数值模拟、极限平衡法和可靠度分析方法整合应用，能提高边坡稳定性评价结论的可信度，实现采用线性方法更合理地分析非线性边坡稳定性问题的目的，其方法是可行的。

It is an especially important topic of development for slope stability analysis method investigation in geotechnical engineering. In the stage of stripping topsoil within first mining area in the 3rd Baiyinhua opencast coal mine, the stability of composite slope constituted of non working wall and outer dump is one of the issues that need to be addressed urgently by the mine. Numerical simulation, limit equilibrium method and reliability analysis are integrated together based on FLAC3D platform, taking “stress-strain mechanical behavior”, “reliability” and “stability factor” as multi-indexes for evaluating, and the slope stability analysis is accomplished comprehensively by this integrated method. According to the "geotechnical engineering investigation norms" (GB50021-2001), Hawke-Brown experience strength criteria and similar engineering experience, the physical and mechanical indicators of slope rock (clay) are anlysized firstly, and the conclusion that the rock type of slope belongs to soft-half rigidity rock is drawn. Lithology, structural face, ground-water, shape of slope and outer load have important influence on the slope stability according to engineering geological qualitative analysis. The sensitivity of factors, such as friction angle, density, cohesion and ground-water, are smaller in order to slope stability according to multi-factor sensitivity quantitative analysis. During the analysis of slope stability, FLAC3D numerical model was established by softwares such as Surfer, ANSYS software firstly. With FLAC3D Numerical Simulation and strength reduction, the paper analysed stress-strain mechanical behavior of slope under the static equilibrium and solid-flow-coupled conditions, and the location and shape of potential sliding surface was defined. Then, Using the Lizheng software and limit equilibrium method, the location of potential sliding surface was certified, and the stability factors of the most dangerous and the designated sliding surface were calculated by using the simplified Bishop method and Janbu method. At last, the stability factor, which was calculated by adopting traditional limit equilibrium method, was considered as an indicator, and the potential sliding surface, which defined by the numerical simulation, was considered as specified surface, the reliability index and failure probability of slope were calculated according to the basal principle of first-order second-moment method. Through analysis, it is shown that, from different aspects by different methods and different evaluation indicators, the composite slope under the current state is in a stable state, but the local slope of Dump is under the unacceptable level of risk. Otherwise, the complicated destruction model of composite slope is the arc-shaped, plane shearing and unloading damage etc. All the researches are well accord with the actual situation at the scene. The research show that it is feasible that numerical simulation, limit equilibrium method and reliability analysis are integrated together based on FLAC3D platform, and it will promote the credibility of slope stability evaluation, to reaching a goal, namely, appling the linear method to slove the nonlinear question of slope stability.