Research On Influence Of Jointless Turnout Under Temperature Load And Maintenance Measures For High-Speed Railway

The continuous welded rail with welded turnout eliminates the joint impact,significantly improves the smoothness of the line,and extends the service life of the line equipment,which is a widely used structural type of railway in China.As an important link to realize the cross-zone seamless line,the design,laying and maintenance of the seamless switch are always the focus of the public works department.According to the different design concepts of seamless switch structure in different countries,this paper focuses on comparing the internal force transfer structure of switches,especially the difference between the core rail and the end,the switch and the end setting,through digestion and absorption of foreign experience and lessons,combined with the development history of China’s seamless switch structure,This paper summarizes the research on the layout standard of the structure design,checking,paving,connecting bolts and observation piles of the more mature seamless turnout at present.By using finite element simulation software and based on the structural characteristics of switch No.18 of the passenger special line,a seamless switch model is established,and the influence of rail foundation,track and force transfer structure,and two sets of switch connection modes on the stress of seamless switches under temperature load is analyzed.Combined with the on-site maintenance and repair problems of public works,corresponding maintenance and repair measures are proposed.1.According to the results of the finite element simulation calculation when the temperature changes by 50℃,the temperature force distribution is only affected by the resistance of the fastener and the force transfer structure of the ruts.The additional temperature force of the outer basic rail is mainly transferred by the force transfer structure of the ruts.The temperature force of the inner guide rail is borne by the fastener,and the switch rail is free to expand.2.The temperature additional force of the basic rail of the ballasted turnout is mainly transmitted through the turnout pillow,and the rutting and force transmission structure has little influence on the size of the temperature additional force,but it can change the distribution of the temperature force.The use of a large gap limit can make the influence range of the additional force longer and the temperature force changes more evenly.3.In the butt turnout,the distribution of temperature force is mainly concentrated on the basic rail due to the large resistance of the fastenings,and the impact on the straight line is small,but the temperature additional force on the basic rail will be transferred to the straight line of the butt turnout due to the small resistance of the ballast bed,which can make the temperature force of the straight line of the butt turnout be about 30% higher,which is the focus of maintenance and maintenance.The temperature force of the clamp line is affected by the length of the clamp line and the structure of the switch and the force transfer.The temperature force can be reduced by about 10% by setting the stop device with large displacement,and the overall effect is limited.4.Put forward targeted suggestions on the daily maintenance and maintenance of seamless switches according to the actual problems in the works section.The switch and force transfer structure should be set up reasonably according to the actual situation on the spot,pay attention to the daily maintenance and anti-expansion inspection of the interbranch lines of the butt switch,complete the seamless transition of the semi-welded seamless switch as much as possible to avoid the occurrence of small gauge in the middle and rear of the switch rail in winter,and strengthen the industrial and electrical integration of the distance between the track and tie at the switch site to prevent the problem of switch loss.5.18 and below the total length of the seamless switch is short,theoretically can not form a fixed area within the range of the switch,so in the stress release of the switch,it is appropriate to use the release before and after the connection,keep the switch stationary release scheme.