Regional Distribution Of Seepage Field And Prediction Of Water Inflow For Extra-long Mountain Tunnel Under Complex Conditions

With the large-scale infrastructure resulted from the rapid economic development, more and more tunnel projects are springing up, which makes our China into the country with the longest length as well as the largest number of tunnels. At the same time there are too many complex engineering geology and hydrogeology for the projects to cross in such vast territory of our country. Especially in the south of China, tunnels face more mountains with high-altitude, abundant groundwater resources. How to protect the tunnel structural safety as well as groundwater resources and ecological environment during the tunnel operation and construction has become the key issues.Nibashan tunnel is the depthest tunnel under construction in our country which is1648meters. The geological structure and hydrogeological conditions are very complex.With poor natural and geographical conditions and rich groundwater, the tunnel will occer high pressure Gushing water, large deformation, faults and other geological disastersins. In such great-depth and rich-water surrounding layers, face disasters such as burst mud, spring water, especially in crushing soft rock area. Groundwater is directly related to the role of the surrounding rock, lining the tunnel construction safety and durability of the structure used. But the researches in this area are short of support of system theory. So serious arbitrariness and blindness are showen when tunnel project confronts these kinds of events.It is necessary to research on regional flow field distribution and prediction of water inflow through nibashan tunnel under conplex conditions by numerical simulation. The main research work are as follows:1. Based on the seepage theory, the paper proposes a suitable flow model of Nibasha Tunnel-an equivalent medium model considering the fault. 2. We construct the hydrogeological conceptual model and mathematical model of the area by the finite difference software VISUAL-MODFLOW, and identify the model and verifty the model, which verifies the validity of the model, and laid the foundation for the study below.3. The thesis makes a research on the law of groundwater distribution and flow in tunnel site under different conditions, including under natural conditions, after the partial excavation of the tunnel and after completion of the tunnel by conceptual model of hydrogeology.Rely on the research,it predicts the tunnel water inflow.4. The article assesses the repair of the tunnel adjacent groundwater in Inflow of water recommendations.