摘要
为认知冻土导热系数测试和计算方法的研究现状,从而服务于冻土温度场的计算,介绍了冻土导热系数的研究背景和导热系数对冻土温度场的贡献,并对冻土的组成和导热系数随不同负温变化的原因进行了分析。阐述了目前冻土导热系数的测试技术、计算方法、理论计算模型及土中固相矿物导热系数的确定方法,并分析了其优缺点和误差存在的原因。对冻土导热系数随温度、干密度、含水率等因素变化的研究成果进行了整理,分析了基于测温法确定冻土导热系数存在的误差及其原因,并初步提出了一种修正冻土导热系数测试结果的方法。在此基础上,提出了对冻土导热系数测试和计算的建议和展望。结果表明:温控环境和测试过程中的相变热对导热系数实测值均存在影响,从未冻水含量的角度修正相变潜热对导热系数测试过程的影响具有理论可行性;线性回归预估模型应考虑土质对测试值的初始影响,从相间热量平衡的角度建立导热系数的理论模型,对于温度场解析问题的研究具有重要作用;考虑土颗粒的多孔特性,推演不随密度变化的土中固相物质导热系数的确定方法,对于提升冻土导热系数计算模型的预测精度具有基础作用;从微观角度出发,建立能够反映土体冻结速率的导热系数模型应是冻土导热系数研究区别于常规土体的重要方向;统筹考虑导热系数、比热和潜热对温度场的影响,从温度场的角度验证导热系数计算模型的可靠度是必要的;所得到的结论可为冻土温度场解析解问题的研究和冻结法施工中的温度场预测提供借鉴。
In order to cognize the current situation of the test and calculation methods of frozen soil thermal conductivity, thus to serve the calculation of temperature field of frozen soil. The research background of frozen soil thermal conductivity and the contribution of thermal conductivity to the temperature field of frozen soil were summarized, the reasons of the composition and thermal conductivity of frozen soil vary with negative temperatures were analyzed. The contents, advantages, disadvantages and errors of the testing technology, calculation method, theoretical calculation model of frozen soil thermal conductivity were introduced, and determination method of solid minerals thermal conductivity were described. The existing research results of frozen soil thermal conductivity with temperature, dry density, moisture content and other factors were summarized. The error and its reasons for the frozen soil thermal conductivity based on the temperature measurement method were analyzed, and a preliminary correction method for the thermal conductivity of frozen soil test was proposed. On the basis, the suggestions and prospects for the test technology and calculation methods of frozen soil thermal conductivity were put forward. The result shows that both temperature control environment and latent heat of phase change have effects on the testing process of thermal conductivity, it is theoretically feasible to modify the effect of latent heat on the thermal conductivity testing process from the view of frozen water content. The linear regression model should consider the initial effect of soil mineral on the thermal conductivity values, the theoretical model of thermal conductivity established from the point of heat balance between phases plays an important role in the studying of temperature field analytical problem. Considering the porous characteristics of soils, deducing the method for determining the thermal conductivity of soil mineral with being independent of densities, which plays a fundamental role in improving the prediction accuracy of the calculation model of frozen soil thermal conductivity. From the view of microcosmic point and considering the difference between frozen soil and conventional soil, it is an important direction to establishing the thermal conductivity model reflecting the freezing rate of soil. Considering the influence of thermal conductivity, specific heat, and latent heat on temperature field, it is necessary to verify the reliability of the calculation model of thermal conductivity from the point of temperature field. The conclusions can be used as reference for the study of analytical solution of frozen soil temperature field and the prediction of temperature field in freezing construction.
作者
陈之祥
李顺群
夏锦红
冯彦芳
刘志锋
CHEN Zhi-xiang;LI Shun-qun;XIA Jin-hong;FENG Yan-fang;LIU Zhi-feng(Department of Engineering Mechanics,Dalian University of Technology,Dalian 116024,Liaoning,China;Tianjin Key Laboratory of Soft Soil Characteristics and Engineering Environment,Tianjin Chengjian University. Tianjin 300384 ,China;School of Civil Engineering and Architecture,Xinxiang University,Xinxiang 453003,Henan,China;School of Materials and Engineering,Tianjin Chengjian University,Tianjin 300384,China)
出处
《建筑科学与工程学报》
CAS
北大核心
2019年第2期101-115,共15页
Journal of Architecture and Civil Engineering
基金
国家自然科学基金项目(41472253)
天津市自然科学基金重点项目(16JCZDJC39000)
天津市建设系统科学技术发展计划项目(2016-25)
关键词
岩土工程
冻土
导热系数
未冻水含量
计算模型
测温法
geotechnical engineering
frozen soil
thermal conductivity
unfrozen water content
calculation model
temperature measurement method
