CRTSⅡ型板式无砟轨道结构早期温度场特征研究

Study on the Characteristics of Early Temperature Field of CRTSⅡSlab Ballastless Track Structure

以京沪高速铁路CRTSⅡ型板式无砟轨道为研究对象,通过对轨道结构早期纵连阶段温度场长达半年的现场观测,研究CRTSⅡ型板式无砟轨道结构早期温度场的分布及变化规律.结果表明：轨道板面温度、轨道板温度梯度及气温三者的变化规律基本一致,且呈周期性变化,变化周期均为1d;随着轨道结构深度的增加,其温度和温度梯度的波动幅度均逐渐减小且相位差逐渐增大,当深度超出轨道板厚度（20 cm）后,二者波动幅度很小且基本趋于稳定;CA砂浆层和支承层的温度梯度变化较小;板面温度的高低决定了轨道板温度梯度的大小.采用最小二乘法对板式轨道结构早期温度场进行回归分析,建立轨道板内不同深度处的温度预估模型及轨道板面最高温度、轨道板最大温度梯度的预估模型,相关系数为0.812～0.968,表明预估模型精度较高.

Taking the CRTS Ⅱ slab ballastless track construction of Beijing-Shanghai high-speed railway as study object,the distribution and change rules of early temperature field of CRTS Ⅱ slab ballastless track were analyzed according to half a year field observation of the temperature field of track structure at its early longitudinal continuous stage.The results show that the change rules of track slab surface temperature,track slab temperature gradient and air temperature are basically the same.The change is cyclic and the change cycle is 1 day.Along with the increasing depth of track structure,the fluctuation ranges of temperature and temperature gradient are gradually reduced while the phase difference gradually increases.Both fluctuation ranges are very small and tend to be stable when the depth exceeds the thickness （20 cm）of track slab.The temperature gradients of CA mortar layer and supporting layer change slightly.The temperature gradient of track slab is dominated by the temperature of track slab surface.According to the regression analysis of the early temperature field of track slab structure by least square method,the prediction models of the temperature at different depths within the thickness of track slab,the maximum temperature of track slab surface,and the maximum temperature gradient of track slab are established.The correlation coefficient is.0.812～0.968,which shows that the prediction models are of higher accuracy.