Research On The Influence Of Groundwater Emissions To The Surrounding Water Environment In Guanjiao Tunnel

With the further development of the western development and the trend of railway construction with high speed and heavy-duty, the construction need of a large number of mountain tunnels which are deeply buried, as well as how to control the tonnage of the tunnel, the protection of groundwater resources and the ecological environment have become key issues during the tunnel design, construction and operation process. This dissertation refers the constructing case project of Guanjiao tunnel from Xining to Geermu, researches the impact of underground water drainage of Guanjiao tunnel on the surrounding water environment.Scopes and Methodologies:(1) Based on the geological investigation report of Guanjiao tunnel, this issertation analyzed of the geological and hydro-geological conditions, and concluded the coefficient of permeability and the occurrence regularity of surrounding rock groundwater within the project area, which provided and provides value basis for numerical simulation.(2) By applying the FLAC3D software and combining with the Guanjiao tunnel, the undrained models of double tunnel are established. Evolution laws of the seepage field around the tunnel have also been analyzed based on the Fluid-Mechanical Interaction theory.(3) On the numerical simulation basis, the groundwater level's changing condition and the tonnage of the tunnel of different water handling models were analyzed. Meanwhile, the mountain tunnel water handling and the key technologies of water seepage management were explored.Result:(1) In the event of full drainage, tunnel water flow differences and changing trends of groundwater levels have been drawn with and without consideration of seepage-field coupling, which provided upper limit for the controlling emission.(2) This dissertation analyzed the stress value of the full closure on the tunnel ling, concluded that with consideration of the seepage field, the maximum principal stress of the lateral tunnel ling is about 0.1 MPa larger than when without consideration of the seepage field, while it is about 0.05 MPa larger of inner the tunnel ling.(3) The impact of grouting reinforcement ring's thickness and permeability on the restrictions of tunnel displacement is being summed up. The propositional values range is given about the thickness of grouting reinforcement and permeability coefficient within the project area.(4) By Contrasting the value of drawdown in different Q_boundary/Q_lining about the the drainage model and the sealing model, the value of drawdown is 0.76 0.86m and 0.27 0.45m.