基于连续-离散耦合的边坡稳定性分析研究

以河北省某露天铁矿边坡为工程背景，采用连续-离散耦合数值分析方法，对典型边坡断面进行分步开挖，结合强度折减法，计算分析坡体的变形规律和受力特征。连续、离散网格区域分别采用有限差分FLAC和颗粒离散元PFC进行建模，着重从连续-离散模型的数据一致性，剪应变增量的形成、发展与局部位移的关系，连续-离散介质受力与位移过程，离散体细观破裂与坡体塑性变形等方面，对边坡稳定性的耦合分析方法进行研究，从宏观和细观角度对边坡的失稳机制进行了较为全面的探索。结果表明：（1）计算过程中坡体应力和位移在连续域和离散域保持了较高的一致性，连续-离散耦合分析方法适用于边坡稳定性研究；（2）作为边坡失稳判据的剪应变增量变化过程主要受岩土体水平位移控制；（3）细观破裂机制可有效表征边坡的宏观塑性变形；（4）土体颗粒接触力链的方向改变是土体位移和变形的驱动因素。

Slope stability analysis based on technology of continuum-discrete coupling

In this study, the continuum-discrete coupling method is be used to an open-pit iron mine slope in Hebei province. The deformation and stress characteristics in the typical across-section of the slope excavated in the difference time steps are simulated in combination with the strength reduction method. Continuum and discrete region are analyzed with FLAC and PFC procedures respectively. Emphatically in terms of the data consistency for continuum-discrete models, the relations of shear strain increment formation, development with local displacement, the force and displacement transformation process of continuum and discrete media, meso-crack of discrete media and plastic deformation of slope mass and so on, the applicability of the continuum-discrete coupling method are studied. Based this method, the instability mechanism of the slope is illustrated from macro and micro aspects. The results show that, stress and displacement of slope in the continuum and discrete region maintain a superior consistency in the process of computation, showing the continuum-discrete coupling method is applicable to slope stability analysis; the varition of shear strain increment acting as slope instability criterion is controlled by horizontal displacement of rock or/and soil mass; the meso-crack mechanism can characterize macro plastic deformation effectively; the change of contact force chain direction between soil particles is the driving factor of displacement and deformation of soil mass.