库水位变化对观音坪滑坡稳定性影响的数值分析

摘要

In order to explore the influence of landslide stability by the change of reservoir water level,a reservoir bank landslide in Southwest China is researched.According to the engineering geological conditions and genetic mechanism of landslide,the effect of variation of water level impacting on the landslide stability and sliding mode based on fluid-solid coupling is analyzed through a three-dimensional numerical model.The plastic zone distribution and X-displacements under nature state,initial impoundment,water level rise and water level fall are obtained through numerical calculation.The stability of reservoir bank landslide under different water levels is analyzed comprehensively.The results of numerical calculation and actual deformation features are also taken into account in the analysis.The results show the follows.The landslide deformation due to the first water storage of reservoir can cause the slope into unstable state.The water level rise has little influences on the landslide stability.The landslide stability is reduced sharply and the slope is likely to occur instability damage when the water level falls.The failure mode of landslide would be diverted from push mode to drag mode after the water storage of reservoir.%为深入探究水库水位变化对滑坡稳定的影响，以西南地区某库岸滑坡为例，在探明滑坡工程地质条件和成因机制的基础上，通过建立三维数值模型来分析流固耦合作用下库水位变化对库岸滑坡稳定性及滑动模式的影响。通过数值计算，获得水库天然状态、初期蓄水、水位上升和下降条件下滑坡体内塑性区分布和x方向位移变化情况。结合数值计算结果和滑坡实际变形破坏规律综合分析库水位变化对库岸滑坡稳定性的影响。分析结果显示，水库初期蓄水造成滑坡体变形开裂，使坡体处于不稳定状态；水位上升对滑坡稳定性影响较小，水位下降后滑坡稳定性大幅降低，极可能发生失稳破坏；水库蓄水后坡体滑动模式由推移式向牵引式转变。