双块式无砟轨道温度场试验研究和数值分析

为较准确掌握无砟轨道温度场的分布规律,建立无砟轨道温度与环境温度的对应关系,为温度应力的计算和无砟轨道设计提供基础参数,本文测试了双块式无砟轨道不同部件、不同位置的温度和环境温度变化情况,建立有限元模型对无砟轨道温度场进行了数值模拟和对比.实测数据及数值模拟的结果均表明:道床板温度随外界气温呈以日为周期的周期性变化,秋季平均每天的升温时间约为8 h,降温约16 h;由于热交换条件的差异,距轨道表面越远,轨道温度受环境气温的影响越小,道床板角部的温度变化幅度大于中部,支撑层与基床表层的温度变化幅度很小;道床板内存在较大的温度梯度,随着距表面距离的增大,温度梯度逐渐减小,至支撑层时温度梯度可忽略不计;采用有限元模拟的方法获取无砟轨道温度随气温变化规律是可行的.

Experimental research and numerical analysis of temperature field on bi-block ballastless track

In order to accurately grasp the distribution rule of temperature field on ballastless track, establish corresponding relationship between track temperature and environment temperature and provide basic parameters for the calculation of temperature stress and the design of ballastless track, the temperature in different parts and at different location of the track and environment temperature were tested in this paper. At the same time finite element model was established for numerical simulation and comparison of ballastless track temperature field. The measured data and the results of numerical simulation show that the temperature of track plate changed periodically with the ambient temperature in a day of cycles, the heating time per day is about 8 hours, cooling about 16 hours in the autumn. Due to the difference in thermal exchange conditions, the greater the distance away from the track surface, the smaller the track temperature is affected by environmental temperature, variation in the temperature of the track plate in the corner is greater than central, the internal temperature in supporting layer and subgrade layer change very little. There are large temperature gradient in the track plate, with the increase of distance away from the track plate surface, the temperature gradient of track decreases and it can be neglected in support layer. The method of finite element simulation for ballastless track temperature with the environmental temperature change law is feasible.