Study On Disease Characteristics Of High-Speed Railway Ballastless Track And Its Impact On Driving Safety And Quality

The ballastless track has outstanding features such as beautiful and clean,uniform stiffness,high stability,high stability,long service life and less maintenance.Therefore,the ballastless track has been widely used in high-speed railways around the world.However,the external loads of ballastless track structure during service are complex and changeable,and the mechanical properties of materials of different components are also quite different.Thus,various track diseases appear in the ballastless track structure during its service.When the disease of ballastless track develops to a certain stage,it will lead to no longer matching between the train and the underlying foundation,which will further accelerate the development of ballastless track disease,and ultimately endanger the safety and quality of driving.Therefore,it is of great engineering significance to study the influence of ballastless track structure diseases on driving comfort and safety and to determine the corresponding maintenance limits.The main contents of this paper are as follows:(1)The research status of vehicle-track coupling dynamics and typical diseases of ballastless track at home and abroad is summarized.The shortcomings of existing research are pointed out.Finally,the research contents and research ideas of this paper are put forward.(2)The LS-DYNA software is used to establish the vehicle-track-subgrade coupling dynamics analysis model,and the model verification is carried out to ensure the correctness of the calculation model established in this paper.(3)The elastic modulus of CA mortar,the length of CA mortar gap,the height of CA mortar gap and the stiffness of fasteners are selected as random variables.The Box-Behnken test design method is used to design the response surface test point,and the corresponding response surface model is constructed.Based on the reliability theory,the long-term service performance of ballastless track with CA mortar gap is analyzed.(4)The vehicle-track coupling dynamic model considering the uneven performance of subgrade is established.The uneven area of subgrade performance,compaction index of subgrade and stiffness of fasteners are selected as input samples of support vector machine.The dynamic response of wheel-rail system obtained by orthogonal test is taken as output samples of support vector machine.Then,the dynamic response mapping model of wheel-rail system is established.Finally,based on the reliability theory,the grading control criteria for the uneven performance of subgrade are determined.