Numerical Simulation Analysis Of Dynamic Response Of Cross Tunnel Under Train Load

With the rapid construction of railway complex line in our country and restrained to the geology or existing buildings’ influence,many cross tunnels are inevitable,the railway tunnels and underground urban tunnels are subjected to the effect of train load,and the vibration characteristic of tunnel structure causes the surrounding soil to displace because of the vibration caused by the train passing.Through reading literature and summarizing research methods,it can be seen that there are relatively few studies on the dynamic response generated by the spatial position of wheel and rail forces successively passing through the cross tunnel structure when the train is moving.Therefore,it is of great practical significance to select a typical orthogonal three-dimensional cross tunnel model and study the dynamic response of each characteristic point of the tunnel structure when the train load wheel passes successively.The main research contents of this thesis are as follows:(1)Based on the dynamics knowledge,this thesis summarizes the mechanism of train vibration analysis and the method of understanding the dynamic equation of the structure and summarizes the way of applying the moving load of the train,which provides the theoretical basis for the establishment of the appropriate model and the solution of the subsequent model.(2)Based on the numerical simulation method,the continuous train running in the tunnel is simulated,and the dynamic response of the train wheel and rail force to different parts of the tunnel is studied,and the maximum response value of the train car connection to the tunnel is revealed.(3)The dynamic response of the trains passing through the common section and cross section of the cross-tunnel under different modes of up,down and down tunnels is analyzed in detail,and the most dangerous mode of traffic and the most dangerous section are obtained.(4)According to the existing research results,the change rules of displacement and acceleration are analyzed and compared in the most dangerous situation from the aspects of vertical displacement and vertical acceleration,under three factors: axle load of the train,different running speeds of the train and different grades of the surrounding rock.