利用热管-保温材料复合结构提高冻土区路基稳定性研究

Study on Enhancing the Stability of Permafrost Embankments with Thermosyphon-Insulated Boards

热管-保温材料复合路基是青藏铁路中应用广泛的一种新型路基结构形式.通过数学模型分析,推导出应用于青藏铁路冻土路基中的热管的热流表达式,并用热焓法考虑冻土相变问题,对该路基结构形式及在无保温材料情况下施工20 a后的路基温度场进行数值模拟.数值模拟表明:保温材料能够有效地阻止热量从路基面向下传入地基中,使0℃等温线始终在保温板底层;该路基结构形式为青藏铁路多年冻土区路基的理想结构形式,有利于克服全球变暖的影响.

Thermosyphon-Insulated Boards Permafrost Embankment is widely used in Qinghai-Tibet railway. Through analysis of mathematical model, this paper deduced the formula to express the heat flux of thermosyphons in permafrost foundation, and simulated the construction formation of both conditions, with insulated boards and without considering the phase change of permafrost, by using the method of enthalpy after the construction up to 20 years. The results can lead to the following conclusions： Insulated board can effectively protect the heat from transferring into the foundations, and the frozen table（0 ℃ contour line） is always around the lower bottom of the boards. This type of the embankments can be used in the permafrost of Qinghai-Tibet railway effectively, which will mitigate the influence of the global warming.