摘要
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。
The ballast layer and crushed-rock layer in railway embankment can be regarded as highly porous media. In this paper, using geological conditio traditional ballast the dynamic theories for incompressible fluid in porous media and considering the temperature and ns of Qinghai-Tibetan railway, a comparative study has been made on the temperature fields of a embankment structure and two kinds of new-type embankment structures （horizontal crushed-rock embankment and U-shaped crushed-rock embankment） of the same embankment heights （5.0m）. The results indicate that in the areas where the mean annual air temperature is -4.0~C and under the assumption that the air temperature will warm up 2.6℃ in 50 years, the traditional ballast embankment will cause greater degradation of the underlying permafrost whereas the horizontal crushed-rock embankment can almost counteract the influences of climatic warming and railway construction. However, the ground temperature beneath it is still higher. On the other hand, the U-shaped crushed-rock embankment can decrease effectively the ground temperature under it, thus ensure the stability of the embankment. Therefore, following the trend of global warming, it is highly recommended that the U-shaped crushedrock embankment, which can protect the railway most Qinghai -Tibetan railway embankment structure in warmer effectively in permafrost regions, should be adopted for the permafrost regions.
出处
《土木工程学报》
EI
CSCD
北大核心
2006年第2期93-97,101,共6页
China Civil Engineering Journal
基金
国家杰出青年科学基金资助项目(40225001)
中国科学院知识创新工程重要方向项目(KZCX3-SW-351)
中国科学院知识创新工程重大项目(KZCX1-SW-04)
关键词
气候变暖
传统道碴路基
新型路基
温度场特征
climatic warming
traditional ballast embankment
new-type embankment
temperature characteristics
