Structure Deformation And Risk Evaluation Of Water Inrush For Anlizhai Tunnel In Karst Area

In our country more than 70% of land area is mountain areas in which the geological conditions are complex and the distribution of karst is very extensive.With the rapid development of economic,a tunnel in the karst area should be constructed to meet the increasing traffic demand.There are prone to cause the geological disaster including inrush of water,mud and others,the larger deformation and stress in the supporting structure and surrounding rock in the construction of tunnel in karst area,and the self-supporting capacity of surrounding rock is weak,which could lead to collapse and other safety accidents and impose a serious security threat on the tunnel construction.Therefore,it is necessary to analysis the stress and deformation characteristic of tunnel structure and the risk of water inrush during tunnel excavation and ensure the safety and reduction of economic for tunnel construction in karst areas.In this paper Anlizhai tunnel in Yuqian railway was taken as a project basis.Combined with the characteristics of tunnel,FLAC3 D was used to establish the 3D numerical model and model the tunnel excavated by three-bench seven-step excavation method.The deformation behaviors of surrounding rock and the construction mechanics of supporting structure for the typical section of tunnel in the karst area was analyzed.By the site survey and engineering experience,the design of face grouting to close design ahead of the tunnel and the advanced grouting program to shutoff water,including materials,parameters and grouting order were optimized.Finally,by the quantification the risk index of water inrush influencing and controlling water inrush,the fuzzy information method was used to evaluate the risk of water inrush of Anlizhai tunnel in karst.The calculated risk level was consistent with the actual project,which should reduce the possibility of accident.