Research On Load Effect And Maintenance Strategy Of CRTSⅢ Slab Ballastless Track Structure During Service

During the service period of CRTSⅢ slab ballastless track structure of high-speed railway,various damage diseases will inevitably occur under the action of train load,temperature and its own material deterioration,which affects the safety and applicability of ballastless track structure during the service period.In order to ensure the safety and stability of ballastless track structure during service,this thesis studies the maintenance strategy of ballastless track structure based on time-varying reliability theory,and analyzes the actual examples of track structure under different failure modes.The main work of this thesis is as follows:(1)The full-scale test of CRTSⅢ slab ballastless track structure system is completed in the environmental box.The relative displacement between layers and the longitudinal and transverse strain of concrete at the typical position of ballastless track structure under the action of train static load,positive temperature gradient and their combined action are tested.The variation laws of displacement and concrete strain of ballastless track structure under different loads are obtained,which provides a reference for the design and maintenance of ballastless track structure.(2)Based on the beam analysis theory of ballastless track structure,the spatial finite element model of CRTS III slab ballastless track structure is established,and the mechanical effects of ballastless track structure under different loads are analyzed;The bending moments of different sections of each structural layer of track structure under different loads are obtained,which provides theoretical support for the time-varying reliability calculation of ballastless track structure.(3)Combined with the load effect of finite element model analysis,the time-varying function of ballastless track structure under different failure modes is established.The time-varying reliability index of function is calculated based on the multi-point estimation method of Gauss-Hermite integral.The calculation equations of life and cost of ballastless track structure under different maintenance measures are proposed.Combined with the time-varying reliability index,the optimization model of track structure maintenance strategy is established,The actual examples of ballastless track structure under different failure modes are verified and analyzed.