Abstract A poor cooling effect on warm permafrost (> −1.0 °C) was observed in the crushed-rock revetment embankment (CRRE), which is widely used in the Qinghai-Tibet Railway. The filling of the porous rock layers caused by wind-blown sand and rock-weathering in the Qinghai-Tibet Plateau can further weaken the cooling capacity of the CRRE and may cause instability of the railway vehicles. This study describes a novel slope-cooling structure (NSCS), which combines a CRRE and a slope-warming prevention measure. A full-scale embankment was built using the new design in a warm permafrost region of the plateau. Ground temperatures and air speeds in the pore space of rock layer of the slopes were monitored. The thermal characteristics of the NSCS were evaluated along with its cooling performance. The results indicated that the new slope structure produced an effective cooling process on the side-slopes and the subgrade permafrost. The permafrost table was elevated and the ground temperatures at the embankment shoulders showed a decreasing trend after construction, particularly under the shady side. Asymmetrical convection process, which exhibits a significantly higher air speed and frequency in winters than those in summers, was observed to occur in the rock layers of the new structure. The NSCS decreases the heat absorption during summers and thus is beneficial for the heat-dissipating of the side-slopes. Moreover, the NSCS can reduce the sunny-shady slope temperature difference, which is induced by embankment orientation; therefore, the symmetry of the embankment temperature distribution is maintained. In general, these cooling characteristics contribute to the enhancement of thermal stability of the embankment and confirm the application of the NSCS as an effective method for the design and maintenance of embankments formed on warm permafrost.

中文翻译：

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青藏高原多年冻土路堤坡冷结构热学特性现场调查

摘要 在青藏铁路广泛使用的碎石护岸堤（CRRE）中观察到对温暖多年冻土（> -1.0 °C）的冷却效果不佳。青藏高原风沙和岩石风化造成的多孔岩层充填会进一步削弱中车的冷却能力，并可能造成铁路车辆的失稳。本研究描述了一种新型边坡降温结构 (NSCS)，它结合了 CRRE 和边坡升温预防措施。使用新设计在高原温暖的永久冻土区建造了一个全尺寸的路堤。监测边坡岩层孔隙空间的地温和风速。评估了 NSCS 的热特性及其冷却性能。结果表明，新的边坡结构对边坡和路基多年冻土产生了有效的冷却过程。施工后多年冻土台面升高，路堤肩部地温呈下降趋势，尤其是在阴侧下方。在新结构的岩层中观察到非对称对流过程，冬季的空气速度和频率明显高于夏季的空气速度和频率。NSCS减少了夏季的热量吸收，从而有利于边坡的散热。此外，NSCS可以减少路堤朝向引起的阳阴坡温差；因此，路堤温度分布的对称性得以保持。一般来说，