锦屏二级水电站引水隧洞围岩稳定分析及支护设计

锦屏二级水电站引水隧洞地处高山峡谷地区,埋深大、洞线长,高地应力、高外水压力问题突出。按照围岩是地下工程中主要的承载结构这一设计思想,应用弹塑性有限元法分析了锦屏二级水电站引水隧洞开挖及支护过程中围岩的变形规律与特征、围岩应力分布及其变化规律、塑性区范围,比较研究了不同渗控方案对隧洞围岩和衬砌的工作状态的影响,得出了一些对高地下水位条件深埋引水隧洞的支护设计有普遍意义的结论。

STABILITY ANALYSIS AND SUPPORTING DESIGN OF SURROUNDING ROCKS OF DIVERSION TUNNEL FOR JINPING HYDROPOWER STATION

The diversion tunnel for Jinping Hydropower Station is located in the region with high mountainan and great gorge.The surrounding rockmasses of the tunnel are of deep embedded depth,long length and high ground stress.The problems of high stress and high external water pressure are prominent.Based on the design principle that the surrounding rockmass can be regarded as the main supporting structure for underground projects,this paper analyzes the deformation,stress distribution and plastic zone of the surrounding rockmass during the processes of excavation and supporting of the power tunnel for Jinping Hydropower Station project by using elastoplastic FEM.The influence of different seepage control schemes on the working behaviors of the liner and surrounding rock is studied comparatively.According to the numerical results,suggestions for supporting design of diversion tunnel with high groundwater level and deep embedded depth are proposed.