Dynamic coefficient of slab track system on subgrade under high-speed trains

A vehicle-slab track-subgrade three-dimensional finite element coupling dynamic model was established based on vehicle-track coupling dynamic theory,and corresponding program was developed and verified.With the established dynamic model,taking high-speed trains passing slab track on subgrade as an example,dynamic characteristic and corresponding dynamic coefficient of slab track system were theoretically studied under load case of no track irregularity as well as load case of different kinds of track irregularity.The calculated results show that in the load case without track irregularity,the dynamic coefficient of vehicle load and slab track system is small,the value is below 1.2;in the load case of middle-long-wave random track irregularity,the dynamic coefficient of vehicle load is approximately 2.0,dynamic coefficient of slab track system is between 1.70 and 2.06,and there is no big difference between dynamic coefficient of vehicle load and dynamic coefficient of slab track system.Short-wave track irregularity has great influence on the dynamic coefficient of vehicle load,because vibration caused by short-wave track irregularity decays rapidly in slab track system,and the dynamic coefficient of upper part of slab track system is bigger than the dynamic coefficient of lower part of slab track system.