Simplified Calculation of Temperature in Concrete Slabs of Ballastless Track and Influence of Extreme Weather

In order to ascertain the temperature distribution characteristics of a ballastless track, heat transfer mechanisms between the concrete slab and the environment were investigated, and a field temperature test of the ballastless track was conducted. The spectrum analysis method was used to study the relationship between meteorological data and the measured concrete slab temperature. Further, based on thermodynamic principles and experimentation, concrete slab thermal parameters were calculated, and a simplified concrete slab temperature calculation method was established. The predicted and measured results were then compared, the influence of solar radiation, wind, and air temperature on track temperature were studied, and concrete slab temperature distribution characteristics under extreme weather were also analysed. The results show that this calculation method has good accuracy (0.4-3.0℃) and applicability in calculating concrete slab temperature. The concrete slab thermal diffusivity was determined to be 0.004 3 m2/h. Mean air temperature and solar radiation play a leading role in overall concrete slab temperature, and the air temperature amplitude greatly influences the concrete slab temperature gradient. When the wind scale is greater than 4, the concrete slab surface temperature is approximate to the equivalent air temperature. During extreme weather, the temperature at the lower concrete slab surface can reach 50℃, and the temperature gradient can reach 110℃/m.