Monitoring Technology Research On Mechanical Properties Of Elevated Station Track System In Beijing-Shanghai High-Speed Railway

Due to topographical and geological condition restrictions, a considerable number of welded turnouts are set in the elevated structure of high-speed railway. High-speed railway elevated station track system, which is the weakness in high-speed railway, combines the technical characteristics of continuous welded rail, welded turnout, unballasted track as well as bridges. Thus, in order to protect the safety and stability of the train, it’s necessary to build up an automatic long-term monitoring system, testing safe status of high-speed railway track in real time and providing prediction as well as early warning for possible damage.Based on the finite element method and multi-body dynamic theory, this paper establishes the static and dynamic model of unballasted turnout on the high-speed railway bridge, and analyzes the main factors that affect the force and deformation of elevated station track system. Besides, the research of sensitive indicators and areas, the plan about the monitoring content, monitoring methods and layout scheme are also mentioned in this paper. Combined with the field monitoring test in Beijing-Shanghai high-speed railway line, the long-term monitoring system of high-speed railway elevated station is developed, which realized the functions of automatic acquisition and transmission, analysis, forecasting and early warning. Through the long-term monitoring datas, the fine spatial coupled simulation model is validated and the monitoring methods are improved, providing a scientific basis for the monitoring technology of track system in high-speed railway. The main research works are as follows:(1) Establishment of static and dynamic model of unballasted turnout on the high-speed railway bridge.According to structural characteristics and mechanical properties of slab unballasted turnout on the high-speed railway bridge, high-speed turnout-unballasted track-bridge fine model is established due to the finite element theory. Based on the multi-body dynamic theory and vehicle track coupling dynamic theory, a rigid-flexible coupling system modal of vehicle, turnout and bridge is created by adopting the co-simulation technology, which validetes the availability of the model with the data of field test.(2) The research of sensitive area of high-speed railway elevated station track system.Summarize the static and dynamic evaluation criteria of unballasted turnout on the high-speed railway bridge. With the help of the static and dynamic simulation model and evaluation criteria, this paper studied and found the sensitive area of high-speed railway elevated station track system under temperature loads and train loads, putting forward the long-term monitoring contents of high-speed railway track system.(3) The research of long-term monitoring methods and layout scheme of high-speed railway track system.According to the long-term monitoring contents of high-speed railway track system, this paper refers to the fiber grating technology to monitor the force and small deformation of structure and applies video sensing technology to control large deformation of track. The layout scheme of unballasted turnout on bridge is ensured with the theoretical results and correlation theory.(4) Establishment of the long-term online monitoring system of Beijing-Shanghai high-speed railway elevated station and analysis of the long-term monitoring data.Combined with the field monitoring test in Beijing-Shanghai high-speed railway line, the long-term monitoring system of high-speed railway elevated station is established. This system has realized the functions of automatic acquisition and transmission, analysis, forecasting and early warning. Through the analysis of the long-term monitoring data, the regularity of force and deformation of high-speed railway track system are found under long-term load.