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热管路基是青藏铁路最为广泛使用的主动保护多年冻土的措施之一。针对应用于青藏铁路多年冻土工程中的热管类型,考虑路基土体中水的相变问题,建立热管—土体—大气系统的物理和数学模型,采用Carlekin方法求解,推导出考虑全球气温升高的冻土中热管热流密度随时间的变化规律。采用有限单元数值分析方法,利用青藏铁路清水河的气象和地质资料,在热管倾斜角度分别为0,°10,°20,°30,°45,°60°时,研究热管对多年冻土路基的冷却效果及提高路基整体稳定性的作用。研究表明,热管在坡脚埋设的倾斜角度为25°~30°时,对于路基中心、路肩及坡脚下多年冻土上限的抬升效果最佳,有利于保证路基的长期稳定性。
Heat pipe foundations are one of the most widely used measures for the active protection of permafrost on the Qinghai-Tibet Railway. Considering the type of heat pipe used in the permafrost project of the Qinghai-Tibet Railway and considering the water phase transition in subgrade soils, the physical and mathematical models of the heat pipe-soil-atmosphere system are established. The Carlekin method is used to solve the problem. Heat pipe heat flux in high frozen soil changes with time. By means of finite element numerical analysis and using the meteorological and geological data of Qingshui River of Qinghai-Tibet Railway, when the heat pipe tilt angles are 0 °, 10 °, 20 °, 30 °, 45 ° and 60 ° respectively, the effect of heat pipe on the permafrost embankment Cooling effect and improve the overall stability of the subgrade. The results show that when the inclined angle of the heat pipe buried in the slope foot is between 25 ° and 30 °, the lifting effect of permafrost upper limit at the foot of the subgrade, the shoulder and the slope is the best, which is in favor of ensuring the long-term stability of the subgrade.