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热管-保温板复合路基是青藏铁路应用广泛的一种新型路基结构形式。通过数学模型分析,推导出用于青藏铁路冻土路基热管的热流表达式,并用热焓法考虑冻土相变问题对该路基结构形式及无保温板情况施工后20年的路基温度场进行数值模拟。通过数值模拟可知:保温板能够有效地阻止热量由路基面向下传入地基中,使0℃等温线始终在保温板底层;复合路基多年冻土上限的位置要比无保温板时的高;该结构形式对路基中心、路肩和坡脚下的多年冻土上限抬升的综合效果更好;考虑施工条件后,复合路基在保温板铺设距离天然地面之上0.3~0.6 m对于路基稳定性最为有利;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。
Heat pipe - insulation board composite subgrade is the Qinghai-Tibet Railway widely used in a new type of subgrade structure. Through the mathematical model analysis, the heat flow expression of the heat pipe for the Qinghai-Tibet Railway permafrost subduction roadbed is deduced, and the temperature field of the subgrade 20 years after the construction of the subgrade structure and the non-insulation board is considered by the enthalpy method considering the frozen soil phase change. simulation. The numerical simulation shows that the heat insulation board can effectively prevent the heat from entering the foundation from the subgrade and make the 0 ℃ isotherm always on the bottom of the insulation board. The upper limit of permafrost in the composite subgrade is higher than that of the non-insulation board The comprehensive effect of the structure form on the permafrost ceiling uplift at the foot of the embankment center, the shoulder and the slope is better; considering the construction conditions, the composite subgrade is most favorable for the subgrade stability when laying the insulation board 0.3 ~ 0.6 m above the natural ground; The subgrade structure is the ideal structural form of subgrade in the permafrost region of the Qinghai-Tibet Railway, which is helpful to overcome the impact of global warming.