Study On The Secondary Influence Of The Groundwater Environment For The Rebuilt Tunnel In Zhongliangshan Area

With the development of China’s economy and the progress of engineering technology,the process of urbanization has steadily accelerated so that the construction of highway tunnels and railway tunnels has continuously developed.The rapid construction of the tunnel will help to promote cities’ development,but it also damages the groundwater environment.Especially in the southwestern part of China,the tunnel excavation will break out the balance of the groundwater system,which leads to the waste of water resources and the destruction of the water environment.In this paper,the author analyzes the secondary influence analysis of groundwater environment for rebuilt tunnel of Zhongliangshan area.Through the detailed field geological survey and indoor simulation analysis,and using the VISUAL MODFLOW of groundwater numerical simulation software to establish three-dimensional numerical model of groundwater in Huayan tunnel,analyzing and studying the influence law of the regional hydrogeological conditions and the construction conditions of the tunnel on the groundwater environment to provide reference basis for the recovery and prevention and cure of groundwater environment.Conclusions are as follows:1.Through field investigation and previous survey results,then this paper summaries the characteristics of regional geological environment.This paper analyzes from the three aspects of regional physical geography,regional geological conditions and regional hydrological conditions so that concluding the great meteorological conditions in the area,the geomorphic types and the complexity of geological structures,the large change of strata lithology,the groundwater is rich and the geological environment is complex.2.Through studying the impact of Zhongliangshan tunnel on the groundwater environment,it concluded that the influence of tunnel construction on the groundwater environment is limited.The results show that the area of east valley groundwater systems is closely connected and wide distribution,west valley groundwater contact is relatively small,which is greater than that on the west side of the valley.3.It has established the conceptual model and mathematical model of the initial three-dimensional seepage field of the area of Zhongliangshan region and Huafu tunnel and three-dimensional seepage field of Zhongliangshan coal mine,and simulated area generalized as an inhomogeneous anisotropic porous medium.It uses the simulation of VISUAL MODFLOW to get initial seepage field of groundwater,and finding the result of simulation accordance with the reality.4.It uses VISUAL MODFLOW to simulate the influence of tunnel on the water environment under different conditions.The simulation results are as follows:(1)Under different working conditions,the displacement decreases with the increasing of operating time.After 10 years of operation,the drainage working conditions and the change rate of displacement under 50% conditions of water shutoff has decreased.(2)The influence range of groundwater environment under drainage condition significantly greater than the water shutoff conditions.The growth rate of the impact area was large before tunnel operation ten years ago,and the growth rate has decreased after the last ten years.(3)When the water plugging capacity increases,the maximum water level decreases obviously.(4)At different tunnel spacing,with the increase of tunnel spacing,the gradient of groundwater level becomes larger than ever,the drainage rate of tunnel increases,and the drainage volume of tunnel increases.Before the tunnel spacing of 5km,the maximum water drop depth decreases,and the water level drop depth increase significantly after 5km.