| In the tunnel construction,groundwater is the main factor impacting the safety,quality and engineering structure stability of the tunnel construction,which is mainly hidden in the tunnel uses process and leads to soil erosion and other environmental issues. Therefore, the master of the groundwater in the tunnel area surrounding rock distribution and occurrence patterns, and the establishment of the hydrological model, quantitative evaluation to the tunnel water gushing is particularly important.Xuefengshan Tunnel No.1, total length of11679m, the maximum depth of about840m, distributes anticlines, faults and other geological structures,and it has complex formation lithology, the surrounding rock types.It is a typical Long Tunnel.The specific work is as follows on the base of the investigation on geological and hydrogeological conditions of Xuefengshan Tunnel No.1:(1) To master the relationship of groundwater changes and tunnel construction water gushing through the analysis of the observational data and the study on the characteristics and types of groundwater occurrence combined with groundwater recharge and runoff.(2) Influence tunnel of hydraulic radius is divided into five independent hydrogeological section and hydrogeological conceptual model is established.(3) Generalizate a mathematical model on the base of conceptualization,and use Visual MODFLOW to establish the three-dimensional numerical model of the hydrogeology section for the simulation of tunnel excavation seepage field through the discretization of the aquifer systems and handling of hydrogeological parameters and boundary conditions.(4)Use the simulation results to predict the tunnel area of water gushing, and regular gushing forecasting methods were analyzed to enhance the predictive accuracy.And finally propose preventive measures to be taken in the construction of tunnel construction and operation of the process to reduce gushing water caused by a variety of hazards. |
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