摘要
为研究冻结过程中土、水和冰三者之间的相互关系,建立了基于冻土骨架的导热系数计算模型.骨架模型由土骨架和冰骨架,以及土、水、冰三相之间的相互关系构成.当温度降低至起始冻结温度时,远离土颗粒的孔隙水最先冻结成冰核;随温度降低,冰核逐渐扩张形成贯通的孔隙冰骨架,冻土中的未冻水则存在于土骨架与冰骨架之间.根据球缺接触的土骨架理想化模型,提出了土骨架与冰骨架相互独立,土骨架与未冻水、冰骨架与未冻水相结合的混合传热模式,建立了饱和冻土的复合传热模型及冻土的导热系数模型,计算得到0℃以下冻土的导热系数理论值.分别将导热系数理论值与Johansen法计算值、混合流法计算值和瞬态法的测试结果进行对比,结果表明,复合传热法的计算值处于Johansen法和混合流法的计算值之间,其整体计算精度优于Johansen法,且计算值与实测值相对误差在10%以内.
In order to study the relationship among soil,water and ice in the thermal conductivity of soil during freezing,we establish the thermal conductivity calculation model based on frozen soil skeleton.The skeleton model consists of the soil skeleton and the ice skeleton,as well as the relationship among the three phases of soil,water and ice.When the temperature decreases to the initial freezing temperature,the pore water far away from the soil particles freezes into ice nuclei first.With the decrease of temperature,the ice core gradually expands to form a perforated pore ice skeleton.The unfrozen water in the frozen soil exists between the soil skeleton and the ice skeleton.According to the ideal model of spherical contact,we put forward the hybrid heat transfer mode which is composed of soil skeleton and ice skeleton,which are independent of each other,soil skeleton mixed with unfrozen water and ice skeleton mixed with unfrozen water.We also establish the three-phase composite heat transfer model of soil,water and ice based on saturated frozen soil and the thermal conductivity model of frozen soil.According to the model,we can obtain the thermal conductivity of frozen soil below 0℃.Compared with the calculated values of Johansen method and the mixed flow method,the results of transient method show that the calculated value of composite heat transfer method is larger than the measured value in the range of-5~0℃,the reason is that the pore ice skeleton is not mature.When the temperature is below-5℃,the calculated value of the composite heat transfer method is larger than the measured value,which is due to the hydrothermal migration in the frozen soil.The calculated values of the composite heat transfer method are between those of the Johansen method and those of the mixed flow method.The overall calculation accuracy is better than that of the Johansen method,and the relative difference between the calculated values and the measured values is less than 10%.
作者
李顺群
张翻
王彦洋
夏锦红
陈之祥
LI Shunqun;ZHANG Fan;WANG Yanyang;XIA Jinhong;CHEN Zhixiang(School of Civil Engineering,Tianjin Chengjian University,Tianjin 300384,P.R.China;Tianjin Key Laboratory of Soft Soil Characteristics and Engineering Environment,Tianjin 300384,P.R.China;Tianjin Construction Engineering Technology Research Institute,Tianjin 300204,P.R.China;School of Civil Engineering and Architecture,Xinxiang University,Xinxiang 453003,Henan Province,P.R.China;State Key Laboratory of Structural Analysis for Industrial Equipment,Dalian University of Technology,Dalian 116085,Liaoning Province,P.R.China)
出处
《深圳大学学报（理工版）》
EI
CAS
CSCD
北大核心
2020年第2期165-172,共8页
Journal of Shenzhen University(Science and Engineering)
基金
国家自然科学基金资助项目(41877251)
国家重点实验室自主研究课题经费资助项目(S18406)
天津市科技支撑重点资助项目(19YFZCSF00820)~~
关键词
岩土工程
冻土
导热系数
土骨架
冰骨架
复合传热模型
未冻水
geotechnical engineering
frozen soil
thermal conductivity
soil skeleton
ice skeleton
composite heat transfer model
unfrozen water
