Study On Characteristics And Influences Of Crts Ⅱ Slab Track Early Temperature Field

In this dissertation, the observation of temperature field and temperature warping deformation of CRTS II slab track in Beijing-Shanghai high-speed railway is carried out, then the performance of CA mortar is tested, and at last, temperature warping calculation model is built to analysis the law of temperature warping and its influencing factors of CRTS Ⅱ slab track, based on the science and technology development plan project of MOR, "Experimental study on the application technology of ballastless track engineering of high-speed railway" (No.2008G031-F).1. The significance, main research contents and research methods of study on characteristics and influences of CRTS II slab track temperature field are put forward according to summarize the research status and existing problems of slab track temperature field and its effects.2. Observing CRTS II slab track early temperature field and researching on its characteristics. Mainly include the following:(1) Before longitudinal connecting when track slab is at the "unit" stage, the changing law of slab surface and bottom temperature is analyzed, and influences of various factors such as atmospheric temperature, solar radiation, hydration heat of CA mortar and different substructure (bridge/subgrade) on the temperature gradient of slab are discussed.(2) After longitudinal connecting when track slab is at the "longitudinal connected" stage, three important relations are obtained such as the relationship between the temperature at different depths of the track structure and the maximum temperature of slab surface, the relationship between the daily maximum air temperature and the maximum temperature of slab surface, the relationship between the maximum temperature of slab surface and the maximum temperature gradient of slab, according to researching on the distribution and changing rule of temperature along the depth direction of track structure.3. Based on basic assumptions of finite element calculation of the slab track temperature warping, calculation models of unit slab and longitudinal connected slab are built and the main calculation parameters are determined. By comparing the modeling calculated results and the observed results, the length boundary conditions and simulation method of the relationship between structure layers in the model are confirmed.4. In order to study on the law of slab temperature warping deformation, considering the gravity and the rail constraint, temperature warping deformation and stress of slab on the bridge/subgrade under the effect of positive or negative temperature gradient are calculated. Then, the alternation of compressive/tensile slab warping stress caused by the alternation of positive/negative temperature gradient in one day is analyzed. At last, according to the comparative analysis of the arithmetic solution, the theoretical solution and the measured results, the accuracy of finite element modeling calculation is tested and verified.5. Aiming at the problem of gap between track structure layers in practical engineering, influences of five major factors such as the material performance of CA mortar (including compression strength, rupture strength and expansivity), the main construction process, elastic modulus of the wide seam, thickness and elastic modulus of CA mortar, different substructures (bridge/subgrade) on temperature warping of CRTS II slab track structure are discussed. Combined with the bond strength of CA mortar measured by push-plate tests, the probability of gap between track structure layers is comprehensively discussed and the effective control measures are put forward.