【作者】 吕超；

【导师】 孙强； 赵春虎；

【作者基本信息】 中国矿业大学 ， 地质工程， 2018， 硕士

【摘要】 土壤热导率参数,特别是现场热导率参数及冻土热导率参数,在地下工程中有着广泛的应用。本文从理论方面建立了土体热导率-电阻率关联模型,通过现场及室内常温与低温重塑土试验,研究了徐州丰县地区现场热导率与土壤埋深、密度、含水率、孔隙度的变化特征;基于冻土的形成机理,结合电阻率、波速响应特征,首次研究了温度影响下热导率、电阻率、波速的综合变化规律,建立了参数之间的内在关联性,得到以下成果:（1）研究区内浅层土主要为粉质黏土及粉土,热导率主要集中在1.4¹.8W·m^-1K^-1之间,随含水率近似直线增长,与密度呈对数函数关系;（2）粉土试样热导率、电阻率、密度两两呈线性关系变化;粉质粘土试样的热导率在20%含水率时普遍较其它含水率高;含水率低于30%时,热导率、电阻率、密度相互之间呈线性关系;热导率与电阻率测试结果与土体热导率-电阻率关联模型一致;（3）热导率、电阻率、波速随温度的变化可分成四个阶段:（1）相变前区;（2）剧烈相变区;（3）过渡区;（4）冻结稳定区;随着温度的下降,热导率与电阻率、波速呈负指数关系,波速与电阻率呈指数关系,相变剧烈区内,热导率呈先急剧增大后逐渐平稳的特征。论文结果可为地热系统及存在热流传播的地下工程提供理论指导。更多还原

【Abstract】 Soil thermal conductivity,especially the thermal conductivity in the field and frozen region,has widely application in underground projects.In this paper,the correlation model of soil thermal conductivity and electrical resistivity is established theoretically.Based on the field test and indoor test on remolded samples,the variations of soil thermal conductivity with soil depth,density,water content and porosity in Fengxian County,Xuzhou,were studied.Based on the formation mechanism of frozen soil,we also studied the variations of thermal conductivity,resistivity and wave velocity under the influence of temperature and analyzed the intrinsic correlation of every two parameters.The main results are as followings.(1)the soil types in the study area are mainly silt and silty clay and the thermal conductivity mainly concentrates on 1.4 W·m-1K-1~1.8W·m-1K-1.The thermal conductivity increases approximately linearly with the water content,and increases with a logarithmic function as the density increases.(2)There is a linear relationship among thermal conductivity,resistivity and density of the silt samples.The thermal conductivity of the sample with 20% water content is higher than that of the other water content.When the water content is below 30%,the thermal conductivity,resistivity and density have a linear relationship with each other.The fitting results of thermal conductivity and resistivity coincide with the correlation model of soil thermal conductivity and electrical resistivity.(3)The thermal conductivity,resistivity and longitudinal wave velocity can be divided into four stages with the change of temperature: pre-phase transformation region,intense phase transformation region,transition region and frozen stable region.The thermal conductivity has a negative exponential relation with resistivity and wave velocity.The wave velocity is exponentially related to resistivity.In the intense phase transformation region,the thermal conductivity increases rapidly and then gradually stabilize.The studies could give guidance to the management of geothermal system and the underground project with heat flow transmission.更多还原