Safety Evaluation Of Fly-over Crossing Tunnel Under Seismic Load

With the rapid development of railway traffic network in our country,the number of high speed railway fly-over crossing tunnels show a growing trend,and our country is also a country with frequent earthquakes,therefore,the crack problem of the secondary lining of the fly-over crossing tunnel under seismic load will certainly become a common and difficult engineering practical problem to be solved.So,this paper mainly studies the fly-over crossing tunnel which has been built in the earthquake prone area,the law of safety factor of the secondary lining of the tunnel varies with the change of the crack under the action of seismic load,then,the security of the fly-over crossing tunnel is evaluated to provide guidance for the second lining crack problem of the three-dimensional cross-tunnel.The main content can be reflected in the following aspects.(1)When the cracks exist in different position and depth of development,the study on the law of safety factors of the lining vault,arch shoulder,arch waist and arch foot are changed with the change of the position and depth of the lining cracks.(2)Based on the effect of crack on the safety of tunnel lining,the safety of the flyover crossing tunnel is evaluated by strength calculation.(3)Through summing up a large number of valuable experience what domestic and foreign scholars have gained on the problem of two-lining crack and the study of tunnel under earthquake loading,then it is based on the research conclusions of the problem of fly-over crossing tunnel with lining cracks under seismic load in this paper,in order to solve the problem what arising from fly-over crossing tunnel with lining cracks under seismic load,the corresponding Suggestions are put forward.