Influence Of Temperature Effect And Pier Settlement On Rail Geometry Of High Speed Bridge-Track System

In recent years,with a rapid development of technology in China,a larger mileage of high-speed track has been increasingly and widely built.However,the constructed tracks are emerging various problems due to external factors such as external environmental temperature changes,rain erosion,and high-speed vehicle power shock.This paper,firstly,reviews previous researches of solar temperature field and its effect,and the influence of settlement on the track of high-speed railway,and elucidates relevant theories of astronomy and heat transfer of structural temperature field in solar environment.In the context of the ballastless track system of CRTS II high-speed railway,the spatial distribution and time-varying law of temperature and temperature gradient of bridge-track system in typical period of four seasons in solar environment are analyzed.And based on this,the most unfavorable autumn and winter solstice days are selected,and the influence mechanism of the effect of solar temperature on the geometry of the ballastless track system on the bridge,and the variation law of the smoothness of ballastless track under the combined action of various settlement forms and sunshine temperature loads is studied.The main work of this paper is as follows:(1)Elucidating relevant theories of astronomy and heat transfer relating to the calculation of structural temperature field in solar environment,introducing composition of the heat load in heat-transferring process between the structure and its surrounding environment,deriving radiation intensity accepted by an arbitrary inclined plane in space based on the calculation formula of solar radiation intensity in the horizontal plane,and defining and exemplifying the space occlusion theory;(2)Explaining the temperature field analysis model and static analysis model modeling method of the CRTS ? ballastless track system on the bridge,introducing the structure and composition of the bridge-track system,describing the process of selection and analysis of model parameters in the modeling process,and carrying out the finite element simulation of the measured temperature field of the track plate so as to verify the correctness of the analytical model;(3)Simulating the solar temperature field of the bridge-track system in typical periods in four seasons,comparing the temperature field and temperature gradient distribution characteristics in the direction of vertical and horizontal bridges of the spring,summer,autumn and winter solstice,obtaining a temperature distribution curve at the most unfavorable time,and analyzing the influence of overlying ballastless track structure on the temperature distribution on the box girder;(4)Analyzing the influence of solar temperature effect on the geometrical shape of the track system on the bridge in the autumn equinox day,indicating an index classification of finite element analysis working condition setting and the track smoothness;analyzing the changing rule of height,level,orbit and gauge smoothness of the bridge-track system under solar environment,and,finally,showing the most unfavorable moment of the rail line shape of the high-speed railway on the bridge under various unsmoothed factors;(5)Studing the influence law of various types of the uneven settlement of piers on the geometrical shape of ballastless track,and the effect of the piers settlement and solar temperature on the smoothness of the track.