Study on Transport of Groundwater of Jinping Cascade-II Hydropower Station with Long Diversion Tunnel Region

Water outburst, which often occurs in the underground construction, is one of the problems in the mountain areas in the southeast of China. Taking the JinPing cascade 2 hydropower station for example, the paper introduced the equivalent infiltration intensity method to simulate the rainfall infiltration, which based on the equivalent continuous isotropic medium model. And with the basic tool of three dimensional finite element method and the basic theory of groundwater dynamics, the water inflow and cone of depression in the zone, through the whole constructing process of diversion tunnel, are analyzed and studied. Under the influence of tunneling and without any supporting measures to deal with the seepage, the maximum water inflow value reaches 26 m³ around, and the conical depression influence radius of water cone achieves about 20KM.While adapting measures that can be concluded as "water blockage combined with water drainage", the quantity of gushing groundwater is decreasing, groundwater level can be recovered, The result of processing satisfy the engineering construction and the surface water environment.