Analysis on the Mechanism of High External Water Pressure andSeepage Field Around the Water Diversion Tunnel andEvaluation of the Effect of Drainage of Tianshengqiao-ⅡHydropower Station
Pan Hengyong; He Jiangda(Sichuan Union University)Wang Zebing(Guiyang Hydroelectric Investigation and Desigu Research Institute, Ministry of Power Industry)
The diversion tunnels of Tianshengqiao-Ⅱ hydropower station traverses many undergroundkarst rivers. During construction large quantity of karst pipe water gushed into the tunnels. According to hydrogeological condition of the karst rivers, the mechanism of high external water pressure is analysed. Two dimensional seepage field is studied to evaluate the effect of lowering the pressure acting on the lining of the diversiontunnels by using a drainage tunnel. Research shows that with a drainage tunnel the external water pressure acting on the lining of the diversion tunnels is greatly reduced. Now a drainage tunnel and its branch tunnels todrain the karst groundwater are designed and the drainage effect is very obvious. Engineering practice has verified that using a drainage tunnel is an effectual measure to lower the external water pressure.
【CateGory Index】： TV139.1