Study On The Negative Effect Of Xueshanliang Tunnel Construction On Underground Water Environment

With the rapid development of tunnel construction, people pay more attention on environment protection, and the negative effect on underwater environment draws more attention than ever. Tunnel construction may cause the seepage of underground water and surface subsidence, and the water has bad effect on the construction and operation. The paper studied the background of hydrogeology engineering of tunnel area, and drew the influence law, then did research on water chemical analysis to find the relationship between water from tunnel and the others. Moreover, the paper predicted the water inflow, at last, evaluated the negative effects of tunnel engineering through the analytic hierarchy process.The paper based on XueShangliang tunnel project, did research on underwater environment and drew conclusion as follows:(1) According to the engineering geological, the conditions of karst region are excellent. But the rainfall is low, with the average rainfall of 729mm per year. The groundwater is buried deep, and most of the tunnel is in vertical circulation zone, and some of the tunnel is in horizontal zone, so the tunnel excavation has little influence on the groundwater.(2)The contact of water chemistry was analyzed between water from tunnel and the others by field sampling of surface water and groundwater. Through the gray correlation analysis method, correlation degree between water from tunnel and precipitation is the maximum. The water from the exit of tunnel and precipitation of the correlation degree is 0.84, however, the degree is 0.39 between Huang Long scenic area, meaning no connection. The water from the entrance of tunnel and precipitation of the correlation degree is 0.72.(3)The tunnel area of XueShanliang Mountains is generalized by numerical simulation including the recharge source rock, water and boundary condition. The simulation including no tunnel construction, tunnel excavation and in abundant water year and tunnel grouted, the inflow is respectively 7281.3 m3/d,14722.8 m3/d,2897.0 m3/d.(4) The negative effect of tunnel excavation on the groundwater is evaluated and analyzed from three aspects of groundwater recharge, groundwater runoff factor and tunnel engineering factors. The negative effect is between weak and medium, so the effect of excavation is weak and medium. Obvious or stocks like water appears inside the tunnel, and there is a little precipitation funnel, local surface water flow is affected, being less.