Study On The Ground Water Environment Impact Prediction And Protection Measures For Yujingshan Tunnel Project

Tunnel is constructed in the surface crust of the earth, where the groundwater is the most active. The excavation of the tunnel, which will probably be a new bleed passage of the surface water or groundwater around especially within the upper engineering geological place, thereby affecting the distribution pattern of groundwater, has some impact on the local groundwater environment. Regional groundwater will decline if the discharge of groundwater is not be controlled, then the groundwater outcrops, well spring, caves, underground rivers and surface water closely linked to the groundwater in the range of influence will be reduced in varying degrees, affecting the life and production of local residents.As the main tunnel of the railway from Leshan to Guiyang, there is Zhaxi water reservoir and Houshan drinking water project which are both drinking-water sources besides wells, springs. underground river and creek on Yujingshan Tunnel’s two-sides and coping. The impact of the tunnel excavation on groundwater environment will be analyzed and predicted in this paper, and protective measures will be proposed.Firstly, engineering geology, hydrogeology, development of karst and drinking-water sources in tunnel zone are analyzed; secondly, the discharge rate of tunnel is calculated using modulus method of groundwater runoff and atmosphere precipitation infiltration way, then with the support of groundwater simulation software Modflow, the influence radius is obtained through the simulation of underground seepage in tunnel zone, results are as follows: the maximum influence radius is 806.6m in the section D3K278+010～D3K279+740, the maximum influence radius is 1773.1m in the section D3K279+740～D3K280+720, the maximum influence radius is 751.3 m in the section D3K280+720～D3K282+120, the maximum influence radius is 2006.2m in the section D3K282+120～D1K285+012. and the two drinking-water sources are in its coverage; At last, the protection measures are put forward including a set of groundwater monitoring solution fit for this tunnel in order to give a similar karst tunnel involved in drinking-water sources with reference.