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由于铁路道碴层和碎块石铺层可以看成是多孔介质,根据多孔介质流体动力学理论,针对青藏铁路的气温和地质条件对路堤高度均为5.0m的传统道碴路基和两种新型路基结构(水平抛石路基和U形抛石路基)的温度场在全球气温变化的背景下进行了分析和比较。结果表明:在年平均气温为-4.0℃,未来50年气温上升2.6℃的情况下,传统道碴路基将会引起其下伏多年冻土的严重退化;水平抛石路基能够抵消气候变暖和铁路修建所带来的负面影响,但其下部冻土温度仍处于较高状态;而U形抛石路基则可以有效降低其下部土体的温度,确保路基的稳定。因此,在全球变暖的大趋势下,推荐该种U形抛石路基作为青藏铁路高温冻土区的路基结构,以便采用优化路基结构最大限度地利用“天然冷源”来确保冻土区的铁路安全。
Because of the ballast layer and the broken stone pavement can be regarded as porous media, according to the hydrodynamic theory of porous media, the traditional ballast embankment with the embankment height of 5.0m and two new types The temperature field of the subgrade structure (horizontal riprap embankment and U-shaped riprap embankment) is analyzed and compared in the context of global temperature changes. The results show that with the average annual temperature of -4.0 ℃ and the temperature rise of 2.6 ℃ in the next 50 years, the traditional ballast subgrade will cause severe degradation of the underlying permafrost. The horizontal riprap embankment can offset the warming of the railway However, the temperature of the permafrost in the lower part is still at a relatively high level. However, the U-shaped rubble subgrade can effectively reduce the temperature of the lower part of the soil so as to ensure the stability of the subgrade. Therefore, under the general trend of global warming, this kind of U-shaped riprap embankment is recommended as the subgrade structure in the permafrost zone of the Qinghai-Tibet Railway in order to optimize the subgrade structure to make full use of “natural cold source” to ensure that the Railway safety.