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冰川冻土 ›› 2002, Vol. 24 ›› Issue (2): 129-133.doi: 10.7522/j.issn.1000-0240.2002.0022

• 冰冻圈与全球变化 • 上一篇    下一篇

工程活动下多年冻土热稳定性评价模型

吴青柏1,2, 朱元林1, 刘永智1   

  1. 1. 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;
    2. 南京大学, 地球科学系地球环境工程计算研究所, 江苏南京, 210093
  • 收稿日期:2001-08-17 修回日期:2001-11-29 出版日期:2002-04-25 发布日期:2012-04-26
  • 基金资助:
    中国科学院知识创新工程重大项目(KZCX-SW-04);国家自然科学基金重大项目(90102006);中国科学院寒区旱区环境与工程研究所创新项目(CACX210047;CACX210086);南京大学博士后基金资助

Assessment Model of Permafrost Thermal Stability under Engineering Activity

WU Qing-bai1,2, ZHU Yuan-lin1, LIU Yong-zhi1   

  1. 1. State Key Laboratory of Frozen Soil Engineering, CAREERI, CAS, Lanzhou Gansu 730000, China;
    2. AECI, Department of Earth Science, Nanjing University, Nanjing Jiangsu 210093, China
  • Received:2001-08-17 Revised:2001-11-29 Online:2002-04-25 Published:2012-04-26

摘要: 提出了用季节融化层底板到潜在季节冻结深度区间沉积物融化所需要的热量与季节冻结层底板温度升高至 0℃所需要的热量之和 (Qt),与夏半年土体吸收的热量 (Q+)的比值来描述冻土热稳定性 (ST=Qt/Q+).根据青藏公路沿线地温温度场的监测资料,对多年冻土热稳定性模型进行了计算,并分析了多年冻土热稳定性与年平均地温、多年冻土顶板温度和季节融化深度间的关系.根据人类工程活动对多年冻土影响,将多年冻土热稳定性分为 4类:热稳定型、热稳定过渡型、热不稳定型和热极不稳定型多年冻土

关键词: 工程活动, 热稳定性, 评价模型

Abstract: In this paper a model of thermal stability is put forward, which is expressed by ratio Qt/Qt, where Qt is the total heat of thawing sediment from the bottom of seasonal thawing layer to the potential seasonal freezing depth and the heat spent in temperature rising to 0 ℃ of the bottom seasonal freezing layer, and Qt is the absorbed heat in the warm season. Based on the monitor data of frozen soil along the Qinghai-Tibetan Highway, the thermal stability model is used to analyze the relationships among thermal stability, mean annual ground temperature, permafrost table temperature and seasonal thawing depth. Analysis results show that thermal stability can well reflect the change of frozen soil under natural state and human activity. Thermal stability has a close relationship with mean annual ground temperature, temperature at the bottom of seasonal thawing layer, and seasonal thawing depth. Permafrost thermal stability linearly changes with permafrost table temperature and mean annual ground temperature Thermal stability increases with mean annual ground temperature decreasing. The higher the MAGT is, the smaller the ratio Qt/Qt is. Permafrost is easy changing with environmental factors. The relationship between permafrost thermal stability and seasonally thawing depth is an exponential one. When permafrost thermal stability is stronger, the absorbed heat in warm season can only result in slight thawing in the sediments from the bottom of the active layer to the potential seasonally freezing depth, and is unable to raise the temperature at the bottom of the active layer to 0 ℃. With permafrost thermal stability weakening, the absorbed heat in warm season can result in greatly thawing in the sediments from the bottom of the active layer and the potential seasonally freezing depth, and is able to raise the temperature at the bottom of the active layer to 0 ℃. According to the classification of permafrost stability, permafrost table change and thermal regime along the Qinghai-Tibetan Highway, permafrost can be divided into four types: thermal stable permafrost, transitional thermal stable permafrost, thermal unstable permafrost and extreme thermal unstable permafrost. Thermal stability reflects the change of comprehensive factors of frozen soil and sensitively responds to the change of environmental factors under human activities.

Key words: engineering activity, thermal stability, predicating model

中图分类号: 

  • P642.14