Vibration performance of a prefabricated steel-spring floating-slab track for urban express rail transit

In order to explore the applicability of the steel spring floating slab track in urban express rail transit，the dynamic interacion between the CRH6 train and the floating slab track was simulated effectively，and the parameter optimization analysis of the floating slab track structure was also performed. Based on the vehicle-track coupled dynamics theory，the CRH6 train-precast steel spring floating slab track coupled dynamic model was established. In the model，the vehicle is regarded as a multi-rigid body system consisting of a car body，a frame and a wheel set. Meanwhile，the lateral，vertical，side-rolling，head-shaking，and the nodding movements of each part are considered. Regarding the rail as the Bernoulli-Euler beam supported by the elastic points，the rail support points are arranged according to the actual fastener node spacing，and the vertical，lateral and rotational degrees of freedom of the left and right strand rails. The vertical direction of the floating slab is regarded as a two-way bending elastic sheet on an elastic foundation，and the horizontal direction of the floating slab is regarded as a rigid body，considering its translational and rotational freedom；the concrete foundation is also regarded as a two-way bending elastic sheet on the elastic foundation. The normal force between the wheel and rail is determined by the Hertz nonlinear elastic contact theory，and the tangential force is determined by the nonlinear creep theory. Research shows that the traditional prefabricated steel spring floating slab track used for low-speed lines can be used in the urban express rail transit and the high-speed railways. The prefabricated steel spring floating slab track for this project can achieve significant vibration reduction effects under the premise of train operation safety. The invention of the side-mounted vibration isolator is a exploration to improve the stability of the floating slab track. Compared with the traditional method of increasing the thickness of the floating slab track to improve the quality and the stability of the track，the floating slab side-mounted vibrator is economical and effective. Therefore，the novel prefabricated steel spring floating slab track can meet the requirements of the urban express rail transit and even high-speed railways. Moreover，the research results can provide support for the dynamic design of the prefabricated steel spring floating slab beds at speeds of 160 km/h.