卡拉水电站边坡稳定及对坝址选择影响分析研究

 卡拉水电站位于雅砻江中游河段四川省凉山州境内，初拟装机1 080 MW。电站所处河段主要为砂板岩构成的纵向河谷，两岸岩层软硬相间，冲沟发育，物理地质作用强烈。在16 km河段内发育了9个大型或特大型滑坡体，总体积约772.05×106 m3。由于近坝址区山势陡峭、水流湍急、河道狭窄，滑坡体规模巨大，一旦失稳，将造成水库淤积或河道堵塞，并危及大坝及其他电站枢纽建筑物的安全，滑坡体的稳定性及其影响成为坝址选址的控制性因素。在环境地质背景研究基础上，对滑坡体稳定性进行宏观判断；通过极限平衡分析方法对典型滑坡体进行稳定计算；在滑坡体破坏规模分析、滑坡涌浪计算的基础上，分析滑坡体失稳后可能造成的工程影响，并按照“先避让、后处理”的原则，在综合考虑水能利用、电站建设条件等因素的基础上，对卡拉水电站坝址选择及下阶段的工作提出了初步意见和建议。

ANALYSIS OF SLOPE STABILITY AND ITS INFLUENCE ON DAM SITE SELECTION OF KALA HYDROPOWER STATION

The Kala hydropower project，with an installed capacity of 1 080 MW，is located in the middle reach of Yalong River in Liangshan autonomous prefecture，Sichuan Province. The river section where the dam is located is mainly composed of consequent strata of sandstone and slate. The valley slopes are intercalated with hard and soft rock stratum，with well developed erosion gullies and strong physical geology process. Within the 16 km-long river section，9 large landslides with a total volume of 772.05×106 m3 are developed. Due to the steep river banks，the rapid river flow，the narrow valley and the large landslides，any landslides might result in serious reservoir sedimentation or river blockage，and thus endanger the dam and other project structures. Therefore，the stability of these landslides and their influences become the critical factors for the selection of dam site. Stability analysis for the landslides is carried out based on the studies of the geology background，and stability of typical landslide is calculated with limit equilibrium method；potential influences on the project in case of landslide failure are studied based on the analysis and calculation of the landslide scale and their possible surges. Finally，following the principle of “first avoiding then treating”and with the comprehensive considerations of the water power utilization and construction condition of the project，recommendation on dam site selection and suggestions for the subsequent works are proposed.