白鹤滩水电站上坝线左拱座楔形体安全性能分析

 白鹤滩水电站上坝线左拱座底部岩体被陡倾断层切割成多个楔形体，坐落于拱坝底部及其下游，其稳定性直接影响到坝基和拱坝的安全。考虑楔形岩体各滑动面上复杂的渗透压力进行拱坝及楔形体安全性能分析，在FLAC3D中编制多种形式水压力施加程序，并以概念模型进行验证。根据数值计算结果，通过分析所选取结构面的典型节点位移变化，研究楔形体的稳定安全度、面安全系数及超载条件下屈服扩展状况，对其安全性能进行综合分析。研究表明：楔形体滑面考虑裂隙水压力和扬压力作用下，底部LS331滑面的安全度低于坝基接触面，上游右岸坝踵处开始出现局部屈服的超载安全系数为1.5，楔形体不能正常运行的超载安全系数为3.1，坝基不能正常运行的超载安全系数为3.3，坝基岩体整体破坏的超载安全系数为5.5。

SAFETY PERFORMANCE ANALYSIS OF ROCK WEDGES UNDER LEFT SKEWBACK OF UPSTREAM DAM LINE IN BAIHETAN HYDROPOWER STATION

The rock wedges under left skewback of the upstream dam line are cut by many steep faults in the dam site of Baihetan Hydropower Station. They locate at the bottom and the downstream of the arch dam. Their stable movement or not will affect the safety of dam foundation and arch dam. The safety performance of arch dam and rock wedges are comprehensively analyzed considering the complicated crack hydraulic pressure in joint planes between rock wedges，various of water pressures are programmed and the approach is validated using the conceptual model in the software fast Lagrangian analysis of continua in 3 dimensions(FLAC3D). According to the results of calculation and the displacement of the selected typical nodes，the stability safety degree，surface safety factor and yield expansion of rock wedges are studied. Research shows that safety degree in sliding surface LS331 is lower than that in contact surface between the dam and the foundation，upstream dam heel of right bank begins to appear local yield when the overload safety coefficient is 1.5 with a consideration of many effects；the rock wedges cannot work normally when the overload safety coefficient is 3.1；the dam foundation can?t work normally when the overload safety coefficient is 3.3；and the rock masses under dam foundation is overall destroyed when the overload safety coefficient is 5.5.