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铁路碎石道碴层能被看作高渗透率的多孔介质,由于其具有较好的通风特性,它的存在改变了寒区铁路路基的顶部热交换条件,对路基温度场产生不可忽视的影响.为了能够实现对寒区铁路路基温度场的更合理预测,基于对铁路碎石道碴层传热和通风特性的研究现状,通过风洞试验对铁路碎石道碴层的通风特性及通风阻力参数进行了试验研究.试验中选用的铁路碎石道碴平均粒径为4.2cm,孔隙率为0.433,对不同空洞风速条件下铁路碎石道碴层中的压力梯度和渗流速度进行了测试分析.结果表明:铁路碎石道碴层中空气渗流速度随着压力梯度的增大而增大,其内部压力梯度与渗流速度之间存在良好的二次非线性关系.通过计算得到铁路碎石道碴层的渗透率和惯性阻力系数,为寒区铁路路基热稳定性的数值研究提供了参数依据.
The ballast layer of railway gravel can be considered as a porous medium with high permeability. Due to its good ventilation characteristics, the existence of its existence changes the conditions of heat exchange at the top of the railway subgrade in cold region and can not neglect the subgrade temperature field In order to achieve a more reasonable prediction of the temperature field of railway subgrade in cold region, based on the research status of heat transfer and ventilation of ballast layer in railway gravel, the ventilation characteristics and ventilation resistance Parameters of the experimental study.Experiment selected railroad ballast ballast average particle size of 4.2cm, porosity of 0.433, under different hole wind speed conditions of the ballast layer of the pressure gradient and seepage velocity of the test analysis The results show that the air seepage velocity in the ballast layer of railroad gravel increases with the increase of pressure gradient and there exists a good quadratic nonlinear relationship between the internal pressure gradient and the seepage velocity.Based on the calculation of the gravel road The permeability and inertia resistance coefficient of the ballast layer provide the basis for the numerical study of the thermal stability of the roadbed in cold region.