考虑岩体劣化的三峡库区顺层岩质边坡破坏分析

Deformation and failure analysis of bedding rocky slope in Three Gorges Reservoir area considering rock mass deterioration

三峡水库在正常运行期间库水位在145.00~175.00 m之间周期性波动,这对库区内广泛发育的顺层岩质岸坡造成损伤劣化,严重影响坡体稳定性。以三峡库区内典型的顺层岩质岸坡青石6号坡作为研究对象,采用FEM/DEM(有限元/离散元)耦合分析的方法模拟其变形破坏全过程。同时结合室内饱和-风干试验结果,讨论库水位长期变动条件下消落带岩体强度与结构的劣化对岸坡变形破坏演化过程的影响。结果表明:当岩体强度逐渐劣化时,仅会加快坡体变形演化速度但不会改变破坏模式;当坡体结构劣化程度增加时,坡体的变形演化速度不仅会加快,变形破坏模式也会随之发生改变。研究成果对库区内顺层岩质岸坡的防灾减灾工作提供了一定的技术支撑。

During normal operation of the Three Gorges Reservoir,the water level of the reservoir fluctuates periodically between 145m and 175m,which is bound to bring damage and deterioration to the widely developed bedding rocky bank slope in the reservoir area and seriously affect the stability of the slope.In this paper,Qingshi 6 slope,a typical bedding rocky bank slope in the Three Gorges Reservoir area,is taken as a research object,and the whole process of deformation and failure is simulated by FEM/DEM(finite element/discrete element)coupling analysis.Combined with the indoor saturation air drying test results,the influence of the deterioration of rock mass strength and structure in the drawdown zone on the deformation and failure process of bank slope under long-term variation of reservoir water level is discussed.The results show that the gradual deterioration of rock strength only acceleratedthe slope deformation process but not changed its failure mode.When the deterioration degree of slope structure increased,it would not only accelerate evolution speed,but also changed the deformation failure mode.The results provide certain technical supports for the disaster prevention and mitigation of bedding rocky bank slope in the reservoir area.