Seismic Stability Of The Loess Tunnel Under Action Of Train And Seepage

With the development of the “One Belt and One Road” national policy,the western region not only faced unprecedented development opportunities in the transportation,but also ushered unpredictable difficult challenge.Because of the special landform and physiognomy of the western region many highway and railway tunnel will be built through the hill.Through the scholars has made a lot of achievements on the stability of surrounding rock tunnel,the coupled seismic stability analysis of the tunnel is only a little,so using the finite element analysis software and the dynamic finite element static strength reduction,this article study the seepage stability of the tunnel under the action of the train vibration loads and rainwater seepage.The main contents are as follows.(1)The structural analysis models of the deep-buried,shallow-buried and super deep-buried tunnel are established under the action of the earthquake(the near field pulse,the near field without pulse and the far field without pulse)and the train load,then the safety factor and plastic strain cloud of the tunnel under critical failure state can be obtained,thus the stability of the tunnel under the different overlying soil thickness is discussed.(2)According to the different rainfall conditions of loess tunnel under the action of the near field pulse,the safety factor and plastic strain cloud can be obtained,thus the stability of the tunnel under the different rainfall conditions are discussed.(3)Considering the combined action of the train load,different rainfall conditions and the seismic of the near field pulse,the stability of the tunnel under the rainfall seepage and the train load are discussed.The numerical results show that the different earthquake effect on the tunnel is not too large under the same overburden soil thickness,the influence of the near field pulse is the maximum,the far field without pulse is the minimum;The safety coefficient of different overburden soil thickness tunnel increase with the increase of the overlaying soil thickness under the action of the same earthquake;Under the action of rain water seepage,the safety coefficient of the tunnel structure reduce the increase of the penetration depth.The safety coefficient under the role of train load and the rain water seepage has a downward trend compared to consider separately train load and the rain water seepage under the same overburden soil thickness.