关键词: 深埋长隧洞;岩溶水系统;地下水分水岭;地下水疏干;滇中引水工程;

Abstract: During construction of tunnels in karst area，there are some problems such as water inrush and drainage of surface-water and groundwater，which affect the water environment.How to reduce or avoid the environmental impact of groundwater and choose a good route is a key strategic issue.Taking line selection of Xianglushan Tunnel in Central-Yunnan Water Diversion Project as the background，and according to the law of karst development，5 lines were compared from vertical zoning，distribution of karst water system and groundwater environmental sensitivity，etc.The selection principle is that the tunnel length in karst area is as short as possible，tunnel should be far away from the discharge area of the karst spring，the line goes through the relatively weak karst developed zone in term of elevation，and goes through the underground watershed area，etc.Mainly considering the environmental impact of groundwater drainage in karst areas，the No.5 scheme is recommended as a representative route.The line basically passes through the underground watershed between Qingshuijiang-Jianchuan Ⅴ-2 karst subsystem and Heqing Xishan Ⅳ-5 karst subsystem.Compared with other lines，its distance in karst is shorter and closer to the underground watershed，avoiding or alleviating the problems of karst water inrush and groundwater environmental impact to the greatest extent.

Key words: deep buried long tunnel；karst water system；groundwater watershed；groundwater drainage；Central-Yunnan Water Diversion Project