Researches On Longitudinal Force Of The CWR With CRTS ? Slab Ballastless Track On Bridges Under Complex Load Conditions

Continuous Welded Rail(CWR)with ballastless track is widely used in high speed railway bridges,as it enjoys many merits.The forces that CWR on bridges bear tend to be complex.Apart from the temperature load,train dynamic load and braking load,it is also influenced by the additional force resulted from extension and flexure of the bridge,track slab and base plate.The additional longitudinal force generated in the interaction among the bridge,track slab and rail is an important factor influencing stability of the CWR with ballastless track on bridges.Excessive rail-track slab-bridge interaction will lead to unstable track and fracture of the track slab and rail which will influence traffic safety on the bridge seriously.CRTS ? slab ballastless track is widely used in Beijing-Tianjin inter-city railway,Beijing-Shanghai High-Speed Railway and Shanghai-Kunming High-speed Railway.And its application to the track on bridges brings a great change to the traditional bridge-track interaction mechanism of and its stress and deformation are different from those of the ballast track and other ballastless tracks obviously.Based on the summarization and analysis of domestic and foreign researches on the longitudinal force,detection and monitoring technology of CWR on bridges,through the combination of theoretical study and on-site measurement,this article studies the longitudinal force and deformation issues of the CWR with CRTS ? slab ballastless track on bridges under complex load conditions.Main researches and achievements of the article are as follows:1.In this research,a refined spatial coupled model for the CWR with CRTS ? slab ballastless track on bridges has been established and a longitudinal force analysis system has been developed.According to the structural composition and features of CRTS ? slab ballastless track on the high-speed railway bridge in China,on the basis of the rail-track slab-bridge interaction principle and finite element method,parametric modeling method is adopted to establish refined spatial coupled finite element models for the CWR with CRTS ? slab ballastless track on multiple simply supported bridges and large-span continuous girder bridge respectively,in which geometry and mechanical property of the rail,fastener,track slab,CA motar,base plate,sliding layer,solidification mechanism,bridge girder,chafing plate,terminal spine,roadbed and hydraulic support layer are considered in details.C#is adopted for re-development of ANSYS and researches on the longitudinal force analysis system of the CWR with CRTS ? slab ballastless track on bridges are made.Such system can realize the setting of the span number and span of the simply supported beam,span of continuous beam,structural parameter and load parameter and also features functions such as rapid modeling,calculation loading,storage of calculation results and automatic processing ofdata.Thus,a longitudinal force calculation and analysis system integrating free input of parameters,refined spatial modeling,calculation loading,accurate data extraction and automatic processing of data is formed.Comparison with the existing research results verifies the validity of the model created in this article and the universality and reliability of the analysis system.2.The research studies longitudinal stress and deformation properties of the CWR with CRTS ? slab ballastless track on bridges under complex temperature load,constant train running speed and braking conditions,and analyzes the rules of how related parameters affect the longitudinal stress and deformation.On the basis of the refined spatial coupled model for the CWR with CRTS ? slab ballastless track on bridges,researches on the longitudinal stress and deformation properties of the track on multiple simply supported bridges and long-span continuous girder bridge under complex temperature load,constant train running speed and braking conditions are made.The rules of how related parameters,such as longitudinal stiffness of fasteners,flexible stiffness of the track slab and base plate,friction coefficient of the sliding layer,longitudinal stiffness of the solidification mechanism and longitudinal stiffness at the top of pier and abutment with fixed support,affect the longitudinal stress and deformation,are investigated.Above works provide theoretical basis and reference for the design,construction and maintenance of the CWR with CRTS ? slab ballastless track on bridges.3.The research also explores the longitudinal stress and deformation properties of the CWR with CRTS ? slab ballastless track on bridges under broken rail and broken slab conditions.Longitudinal force and displacement of the CWR of CRTS ? slab ballastless track on bridges under broken rail and broken slab conditions are calculated and analyzed on the basis of the broken rail and broken slab models.Suggestions on rail fracture position and loading method of the temperature load for the calculation of the rail breaking force are made.Suggestions on crack position,width and depth value for fracture analysis of the track slab on the bridge are made,and the internal stress distribution of the track slab and crack expansion rules are analyzed in details during incomplete fracture of the track slab.4.The research establishes a dynamic analysis model for the train-ballastless track-bridge longitudinal and vertical coupled system and analyzes longitudinal dynamic properties of the train and ballastless track under braking load condition.Vehicle and ballastless track-bridge element are proposed according to the motion features of the train-ballastless track-bridge longitudinal and vertical coupled system.Finite element method and Hamilton principle are adopted to deduce stiffness,mass and damping matrix of the above two elements respectively.Vehicle subsystem and ballastless track-bridge subsystem are established and the dynamic equations of the finite element models are listed respectively.Dynamic analysis method of the train-ballastless track-bridge system with the train braked on the ballastless track on the bridge is proposed on the basis of the vehicle subsystem and ballastless track-bridge subsystem models.The longitudinal dynamic characteristics of the train and ballastless track on the bridge under braking load condition are investigated.5.A long-term monitoring system for the CWR on the high-speed railway bridge is developed and then applied to the super major bridge on the pilot section of Beijing-Shanghai High Speed Railway.Based on DH3819A wireless test and analysis device for the static strain,a real time monitoring and analysis system for the CWR of the high speed railway is established.which comprises of temperature sensors,strain sensors,temperature collection module,strain collection module,data collection controller and remote monitoring module.Then the system is used in the Grand Canal bridge on Beijing-Shanghai High Speed Railway and tests rail temperature,air temperature,plate temperature as well as rail strain.The long-term test data is analyzed.The on-site practical application indicates that,the monitoring system developed has a stable performance and a smooth data acquisition and transmission and can meet requirements for the long term,remote and real time monitoring of the CWR of high speed railway.