岩溶区多软弱层复合边坡变形破坏机制分析

岩溶和软弱层的存在对边坡稳定性有重大影响。为了揭示岩溶作用下复合边坡失稳机制，以富含岩溶区某变电站场区复合边坡为研究对象，通过三维地质建模技术对钻孔数据进行处理，从而准确获取多软弱岩层界面位置以及坡体内岩溶状态。结合AutoCAD软件生成拟研究边坡地质剖面，通过ABAQUS模拟软件与AutoCAD数据接口将典型地质剖面图导入有限元数值模拟软件中，从而构建含岩溶复合边坡数值模型。采用强度折减法分别分析了复合边坡在不含岩溶时、岩溶无充填时、岩溶被黏土充填时的失稳特征。模拟结果表明：多软弱层复合边坡岩层界面对坡体的稳定有决定性作用，坡体滑移破裂均源于岩层界面处，坡体沿岩层分界面剪切滑移贯通成圆弧状潜在破裂面。岩溶对边坡的影响主要由沉降变形引起，岩溶沉降较大时，边坡呈现垮塌为主和岩层界面剪切滑移为辅的破裂形式。理论上，在某些特定情况下，坡体内岩溶对边坡稳定性有积极作用。该研究结果对于指导含岩溶复合边坡防护设计具有重要意义。

Analysis on Deformation and Failure Mechanism of Multi-weak Layer Composite Slope in Karst Region

The existence of karst and weak layer has great influence on slope stability. In order to reveal the instability mechanism of the composite slope under the action of karst, the composite slope in a substation area rich in karst was taken as the research object, and the drilling data were processed by three-dimensional geological modeling technology, so as to accurately obtain the position of the interface of multiple weak rock layers and the karst state in the slope. Combined with AutoCAD software, the geological profile of the slope was generated. Through the interface between ABAQUS simulation software and AutoCAD data, the typical geological profile was imported into the finite element numerical simulation software to obtain the numerical model of the composite slope with karst. The strength reduction method was used to analyze the instability characteristics of composite slope without karst, without karst filling and with karst filled by clay. The simulation results show that: The rock interface of the composite slope with multiple weak layers plays an important role in the stability of the slope. The sliding and fracture of the slope are all derived from the rock interface, and the potential fracture surface is connected into a circular arc along the rock interface. The influence of karst on the slope is mainly caused by the settlement deformation. When the karst settlement is large, the slope is dominated by collapse and supplemented by strata interface slip. Theoretically, the karst in the slope has a positive effect on the stability of the slope in some specific cases. The research results are of great significance for guiding the protection design of compound slope with karst.