| 封闭条件下抛石路堤降温效果及机理的试验研究 |
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| 引用本文： | 赖远明,张明义,喻文兵,高志华.封闭条件下抛石路堤降温效果及机理的试验研究[J].冰川冻土,2004,26(5):576-581. |
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| 作者姓名： | 赖远明 张明义 喻文兵 高志华 |
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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;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;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;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： | 国家自然科学基金
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中国科学院专项基金
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中国科学院知识创新工程项目 |
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| 摘 要： | 在多年冻土地区道路工程的修筑与维护中, 如何保证多年冻土不退化所采取措施的长期可靠度问题日益为人们所关注. 通过室内试验研究了实际工程中半开放半封闭抛石路堤受到风沙或积雪填埋后,在不同温度变幅条件下的降温效果. 实验结果发现: 在满足一定厚度时, 封闭条件下的块石层仍具有良好的降温效果, 具有可变等效导热系数的特性, 在实验中充分体现了"热二极管效应". 在外界温度变幅较大的条件下, 降温速度和降温效率均大于温度变幅较小的情况. 通过对块石层顶底温差与其顶部温度变化关系, 以及块石层内温度场特征的分析, 证实了封闭块石层内自然对流的真实存在和对流的运动发展趋势. 试验结果为抛石路堤降温的长期可靠性提供了依据.
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| 关 键 词： | 封闭 抛石路堤 降温效果 降温机理 |
| 文章编号： | 1000-0240(2004)05-0576-06 |
| 修稿时间： | 2004年4月20日 |
Experimental Study on the Cooling Effect and Mechanism of Closed Ripped-Rock Embankment |
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| LAI Yuan-ming,ZHANG Ming-yi,YU Wen-bing,GAO Zhi-hua ,China.Experimental Study on the Cooling Effect and Mechanism of Closed Ripped-Rock Embankment[J].Journal of Glaciology and Geocryology,2004,26(5):576-581. |
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| Authors: | LAI Yuan-ming ZHANG Ming-yi YU Wen-bing GAO Zhi-hua China |
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| Institution: | LAI Yuan-ming,ZHANG Ming-yi,YU Wen-bing,GAO Zhi-hua 0000,China) |
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| Abstract: | In construction and maintenance of a road in permafrost regions, permafrost becomes the main factor influencing embankment stability. However, the long-term reliability of a measure to protect permafrost from thawing is also caught more and more people's attention. In order to research the cooling effect of semi-open/semi-closed ripped-rock embankment when snowed or sanded, embankment model experiments are carried out under different temperature amplitudes. The results show that the closed ripped-rock layer with a certain thickness has a good cooling effect, a property of alterable thermal conductivity and a thermal diode effect. The cooling speed and efficiency are better under large temperature amplitude than under small temperature amplitude. Furthermore, by analyzing the changing correlation between the top temperature and the temperature difference through the top and bottom of the ripped-stone layer, and taking consideration of the temperature field in the ripped-stone layer, it is found that the cooling effect of the closed embankment model on the soil beneath mainly relies on the thermal conductivity of ripped-stone layer, which changes with the inner natural convection. Namely, when the temperature at the top of the ripped-rock layer is higher than that at the bottom, the natural convection does not occur and heat transfer mainly depends on heat conduction between rocks; but when the temperature of the top is lower than that of the bottom, the natural convection does exist in the ripped-rock layer and so the heat transfer is composed of heat conduction between rocks and air natural convection. Therefore, when ambient temperature is lower, the equivalent thermal conductivity of ripped-rock layer is much larger than that when ambient temperature is higher. The experimental results provide the foundation for the long-term thermal reliability of the ripped-rock embankment. |
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| Keywords: | close condition ripped-rock embankment cooling effect cooling mechanism |
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