Spatiotemporal evolution characteristics of the non-uniform temperature field in CRTS II slab track based on measured meteorological data

Clarifying the spatiotemporal evolution of the temperature field is essential for accurately investigating thermal effects in track structures. This study developed a finite element model based on heat transfer theory and dynamic sunlight area identification to investigate the non-uniform temperature field in CRTS II slab track. Through on-site monitoring experiments, meteorological variation characteristics were captured and used to validate the accuracy of the computational model. The analysis reveals that the temperature field of the track structure under solar radiation exhibits pronounced spatiotemporal non-uniformity. Temperature fluctuations diminish with increasing distance from the track surface, while the occurrence of peak temperatures is progressively delayed, and the vertical temperature gradient of different structural layers at the same time may be in the opposite state. The vertical non-uniformity of the temperature field in the track structure is governed by the thickness of structural layers and the efficiency of vertical heat transfer within materials, while the transverse non-uniformity is primarily determined by the relative position of the sun to the track and the shadowing effects. A distinct nonlinear relationship exists between the track structure temperature and solar radiation intensity. The daily average air temperature predominantly governs the overall temperature variation of the track structure, whereas the daily air temperature amplitude primarily influences the temperature gradient within the structure. The line direction exerts the greatest influence on the temperature distribution between the two sides of the track structure, exhibiting marked seasonal correlation. The sun-shade asymmetry effect is weakest when the line direction angle is 90°.