溪古水电站左岸三维渗流场有限元分析

3-D Finite Element Analysis on Seepage Field of Left Abutment of Xigu Hydropower Station

溢洪洞和排沙洞是溪古水电站重要组成部分,它们往往承受较大的外水压力,而排水孔是降低外水压力最好的渗控措施。为详细了解溪谷水电站左岸山体的渗流场分布以及溢洪洞和排水洞密集排水孔的排水效果,采用有自由面渗流求解的改进截止负压法和排水子结构法等渗流场求解技术,对溪谷水电站左岸溢洪洞和排沙洞三维渗流场进行了有限元数值模拟计算,重点研究了设置排水孔前后左岸岩体渗流场变化和不同排水孔间排距对岩体渗流场影响,给出了左岸溢洪洞和排沙洞优化排水设计方案。

Spillway tunnels and desilting tunnels are the important auxiliary structures of hydropower stations. They often undertake a great external water pressure. The layout of drainage holes is one effective measure to reduce the external water pressure of tunnels. In order to understand the seepage field on the left abutment of Xigu Hydropower Station and the drain effect of the dense drainage holes. By using 3-D finite element analysis on the left abutment of Xigu Hydropower Station, the seepage field around the spillway tunnel and desilting tunnel is worked out. Solving techniques for seepage field with free surface including cut-off negative pressure method and sub-structure method to simulate drainage system are adopted. The influences of drainage holes and their spaces on seepage fields are studied. Suggestions are put forward to optimize the design of drainage holes of the spillway tunnel and desilting tunnel.