Influence of temperature gradient load of slab on dynamic characteristic of train-slab track on subgrade system

A vehicle-slab track-subgrade three-dimensional finite element coupling dynamic model which can take the nonlinear contact state of different parts of slab track-subgrade system into account was established based on the domestic and foreign research results,and the corresponding program was developed and verified.With the established dynamic model,by using high-speed trains passing slab track on subgrade as example,dynamic characteristics of train-slab track on subgrade system were theoretically studied under temperature gradient load of slab and train load.The calculated results show that temperature gradient load of slab has little influence on dynamic characteristics of wheel/rail vertical force,but it has significant effect on dynamic characteristics of different components of slab track,so the adverse influence of temperature gradientload cannot be ignored when studying the dynamic characteristics of different components of slab track.For II-type slab track the influence of temperature gradient load of slab track on dynamic characteristic of train-slab track on subgrade system is greatly related to crack spacing,and the shorter the crack spacing,the smaller the influence of temperature gradient load of slab track.