Study On Temperature Field Features And Effection Of Slab Ballastless Track

With the steady and rapid development of China’s high-speed railway, ballastless track is widely applied in our country because of its outstanding characteristics of good stability, strong durability, less maintenance and repair maintenance and long working life. Temperature has gradually become one of the main design and construction load of ballastless track as a result of its great influence on the track structure. In recent years, the track structure disease occurs frequently and maintenance workload increases due to the influence of temperature load effect, so we need to find the temperature distribution of the ballastless track and study on the influence of temperature load on the track structure. According to the structural characteristics of ballastless track, we study on the temperature field and temperature load effect of ballastless track. The main research work are as follows:1. Reference to the preliminary temperature monitoring experience and the simple temperature field theory analysis, we built ballastless track model scale and did temperature field monitoring test in track test platform in(?) Beijing Jiaotong University. Monitor data display that ballastless track temperature periodic change every day; daily temperature changes in amplitude and rate decreased gradually from the surface to the interior of the track plate, the vertical temperature distribution of the track structure is a nonlinear distribution, the closer to the track plate, the greater the temperature gradient is; there was a significant difference in the temperature distribution of the lateral surface of Yin and Yang.2. Based on the test monitoring data and the basic principles of heat conduction, through the finite element analysis software to establish the CRTSI and CRTSII ballastless track temperature transfer model, further to the slab ballastless track internal temperature field distribution and temperature transfer characteristic analysis. Through research, ballastless track temperature load includes the overall temperature and nonlinear temperature gradient. The nonlinear characteristics of the temperature gradient in the lateral 0.3m of the track slab is obvious, but the track plate is mainly influenced by the vertical temperature gradient, so that in high temperature and cold regions, the thickness of the plate can be increased properly to reduce the influence of temperature gradient.3. Building CRTSI and CRTSII ballastless track temperature deformation model combined with the measured and simulated temperature load combination form to study the effect of temperature load on plate non ballasted track based on the basic principles of heat conduction,. The temperature gradient is one of the main reasons which make the reciprocating void displacement between track plate and mortar layer of I type ballastless track,meanwhile, temperature gradient and overall increasing of temperature is the main reason of mortar layer damage and seam of Ⅱ type ballastless track, at the same time, it also has a large influence on the wide and narrow seam.4. By comparison, the fold line temperature distribution can be used to replace the nonlinear temperature distribution when the regularity analysis is carried out, the linear temperature distribution can be used to design the structure. With loading linear temperature distribution load in bridge-tunnel transition analysis model and analysis model of track irregularity, we found that the deformation is larger with the infect of overall temperature and vertical temperature gradient in the bridge and tunnel transition section temperature buffer zone and tunnel mouth t, meanwhile, track irregularity state is poor in temperature buffer zone and large anchor.All these should be the focus of maintenance.