| 冻土路基表面的融化指数与冻结指数 |
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| 引用本文： | 程国栋,江灏,王可丽,吴青柏.冻土路基表面的融化指数与冻结指数[J].冰川冻土,2003,25(6):603-607. |
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| 作者姓名： | 程国栋 江灏 王可丽 吴青柏 |
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| 作者单位： | 中国科学院,寒区旱区环境与工程研究所冻土工程国家重点实验室,甘肃,兰州,730000 |
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| 基金项目： | 中国科学院知识创新工程项目;KZCX1-SW-04; |
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| 摘 要： | 在冻土层之上筑路，由于会改变地-气界面的热物理特性，进而影响冻土层的热力→动力稳定性，故而修筑一定高度的路基成为保护冻土层所采取的一种常规措施．在修筑路基之后，与路基边坡的朝向有关的热效应是冻土路基工程保护措施必须考虑的问题．在数理分析与数值模拟分析的基础上，给出了可根据气温的年最大和最小月平均值计算路基表面的融化指数与冻结指数以及有关热状况参数的方法，并以青藏铁路北麓河段2002年为例进行了计算分析．实例分析表明，即便是没有修筑道路，北麓河地区的冻土也已经处于临界状态；路基相对的两个坡面，由于朝向不同会造成温度分布的强非均匀性，其中南和偏南方向与北和偏北方向的路基坡面热状况差异最大，有必要对路基相对的两个坡面采用不同的防护措施，一方面改善就地取土修筑路基对其下伏冻土层的直接不良影响，同时也尽可能减小路基表面温度分布的非均匀性，以避免纵向裂缝的发生。
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| 关 键 词： | 冻土 路基 融化指数 冻结指数 坡面热效应 |
| 文章编号： | 1000-0240(2003)06-0603-05 |
| 修稿时间： | 2003年7月9日 |
Thawing Index and Freezing Index on the Embankment Surface in Permafrost Regions |
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| CHENG Guo-dong,JIANG Hao,WANG Ke-li,WU Qing-bai,China.Thawing Index and Freezing Index on the Embankment Surface in Permafrost Regions[J].Journal of Glaciology and Geocryology,2003,25(6):603-607. |
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| Authors: | CHENG Guo-dong JIANG Hao WANG Ke-li WU Qing-bai China |
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| Institution: | CHENG Guo-dong,JIANG Hao,WANG Ke-li,WU Qing-bai0000,China) |
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| Abstract: | Because thermodynamic characteristics are changeable on the interface between atmosphere and ground and then influence thermodynamic stability of permafrost under the interface while a highway or railway built above tundra, embankment of a certain height is used as a usual measure to keep the permafrost stable. After the embankment built, the heating effect that changes with direction of side slopes is a question, which must be taken into account in the engineering measure to keep the embankment frozen. In this paper, based on mathematical physical analyses and numerical simulation, methods for calculating the freezing index and thawing index of embankment surface and some thermodynamic parameters from the maximum and minimum monthly mean air temperature are developed and applied in the Beiluhe passage of the Qinghai-Tibet Railway in 2002 as an example. The quantitative analysis shows that to protect the permafrost along the Qinghai-Tibet railway is necessary and scientific. A case analysis shows that the permafrost in the Beiluhe region is in a critical status, even if no railway built. Slope exposure can cause strong asymmetric temperature distribution. The maximum difference of thermal status is between the south or near south direction and the north or near north direction of the embankment slopes, so it is necessary to take different measures for the two opposite embankment slopes, in order to mitigate the direct negative effect of locally taking soil to build embankment on the underlaying permafrost, to minish the asymmetric temperature distribution on the embankment surface and to avoid lengthways fissure taking place. |
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| Keywords: | thermal effect on slope surface cumulative temperature frozen soil roadbed thawing index freezing index Qinghai-Tibet Railway |
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