秘鲁圣加旺水电站调节库基础液化砂层处理研究

圣加旺水电站是秘鲁东南部圣加旺河干流上的低坝长引水电站,工程位于高地震区,首部枢纽调节库基础部位分布有液化性的含砾砂层,强震下砂土液化将危及建筑物安全。采用粒径法初判和标贯法复判对该部分砂土液化性进行了判别,并根据砂土液化指数对液化等级进行了确定;根据调节库的布置情况及运行条件,优化了地基抗液化处理范围;综合考虑调节库地形、地质条件及靠近河岸等因素,经方案比选,采用了强夯加振冲碎石桩的综合处理措施;调节库基础承载力和边坡稳定性分析表明基础处理设计满足要求。

Study on foundation treatment against liquefaction of sand layer in regulationreservoir design of San Gab′án Hydropower Station,Peru

San Gabán Hydropower Station, on San Gab′án River in East-South of Peru, is a run-of-river type power station with a 16 km long diversion waterway system and a low dam height. The project is located in a high seismic intensity area, and the sand-gravel layer in the regulation reservoir foundation of the head hydro-complex has liquefaction potential, which will endanger the project safety while earthquake occurs. We carried out initial discrimination for liquefaction potential by particle size method and standard penetration test method, and the liquefaction grade of the sand-gravel layer was further evaluated by liquefaction index. Based on the reservoir layout, structure design and operation conditions, the treatment area was optimized. Through the scheme comparison, the comprehensive method of vibro-replacement stone pile and dynamic compaction was adopted according to in-site topographical and geological conditions. Analysis of the foundation bearing capacity and slop stability of the regulation reservoir showed that the above treatment against liquefaction of the sand-gravel layer could meet requirements.