Analysis of Influence of Rail Fastener Stiffness on Vehicle-induced Track-tunnel Vibration
In order to reveal the influence law of dynamic performance parameters of damping fasteners on the vibration characteristics of track-tunnel structures,the dynamic responses of damping fasteners track and common track are measured on site.The vibration characteristics of rail,ballast bed and tunnel wall of two types of tracks are analyzed and compared.The vehicle-track coupling dynamic simulation model and the track-tunnel-ground finite element model are established,and the effects of rail acceleration mobility,track vibration decay rate and tunnel dynamic response under different fastener stiffness condition are analyzed and compared.The results show that the vibrations of rail,track bed and tunnel wall in the damping fasteners track are obviously weakened.Reducing the fastener stiffness has no significant effect on the vibration response of the train body,but can cause the increase of the displacement and acceleration of the rail.Reducing the fastener stiffness will enhance the low-frequency vibration of the rail,but will weaken the high-frequency vibration of the rail.In the longitudinal direction of the rail,the vibration dissipation in the 1-50 Hz frequency band is more rapid,and the vibration in the 500-1 000 Hz frequency band tends to transmit along the longitudinal direction of the rail.The use of damping fasteners has a significant effect on the dynamic response of the tunnel in the 50-200 Hz frequency band,which can effectively reduce the vibration response at the measurement point of the tunnel wall by 6-8 dB.