Stress Analysis Of CRTS? Slab Ballastless Track Structure Of High-speed Railway On Bridge

With its advantages of convenience,efficiency and comfort,high-speed rail is increasingly favored by people.Due to the strict requirements of high-speed rail for orbital settlement,the settlement of soil-based roadbed is large and difficult to control.Therefore,most of the new built railway passenger transport special line currently take the bridge as the main offline basis of ballastless track.The CRTSIII type slab ballastless track has been in operation for less than ten years,and its geometrical dimensions and material selection have not yet been finalized.For the CRTSIII type slab ballastless track on the high-speed railway bridge,the force analysis of the structural layers of the ballastless track is still not perfect when the train passes by.The research of these problems has important theoretical significance and engineering application value for optimizing CRTSIII type slab ballastless track structure and guiding the design and maintenance of CRTSIII slab ballastless track in domestic high-speed railway.Based on the beam-body finite element theory and the finite element software ABAQUS/Explicit module,the train-CRTSIII type slab ballastless track-bridge dynamic coupling dynamic model is established based on the beam-free trajectory data of the Panying Passenger Dedicated Line.The model is reliable by comparison with measured data.Through the model,the most unfavorable position of the train on the CRTSIII type slab ballastless track on the bridge foundation is studied,and the control index is obtained.In addition,the modal analysis of the simply supported beam bridge and the ballastless track system is carried out,and the dynamic response time history curve of the node at the most unfavorable position is plotted.Finally,combined with the most unfavorable position and control index,the influence of parameter variation on the dynamic response of ballastless track is studied by adjusting the speed parameter,the thickness of the isolation layer and the vertical stiffness of the fastener.Research results: The train acts on a span of beam body,the front axle wheelset is above the bridge support,and the rear axle wheelset is at the end of the third track slab,which is the most disadvantageous load position;The fundamental frequency of the model satisfies the requirements of the first-order natural frequency minimum specified by the specification,but the transverse stiffness of the beam body is small,and the arrangement of the steel bars and the transverse prestressing tendons at the flange plates should be strengthened;The dynamic response of each structural layer of ballastless track is sensitive to velocity parameters.The specific performance is that the dynamic response index of each structural layer increases with the increase of vehicle speed.When the train speed exceeds 300 km/h,the vehicle safety index,vertical displacement and vertical acceleration index of each structural layer are significantly affected by vehicle speed.;Therefore,in order to safe and smooth driving of the train,it is recommended that the train speed be controlled within the range of 350km/h or less.The thickness of the isolation layer should be controlled at 3mm~7mm,which is very beneficial to the ballastless track system.The thickness of the isolation layer has no significant effect on the natural frequency of the entire ballastless track structure system.In order to balance the high smoothness of the rail and the smoothness of the train,the optimum range of the vertical stiffness of the fastener is recommended to be 25 MN/m~35 MN/m.The conclusions obtained in this paper can provide reference for further optimization and improvement of CRTSIII type slab ballastless track structure.