摘要
地热资源开发利用背景下,土体导热性能演化研究对工程实践具有重要指导意义。本文以中国北方广泛分布的黏性土为研究对象,采用瞬态平面热源法系统测定不同含水量与含盐量条件下土体的热导率、热扩散系数及比热容,揭示其导热参数演化规律,并基于固-液-气三相组分传热特性差异阐释导热机理。通过对比三种常用热导率模型与试验数据的拟合效果,评估模型对黏性土的适用性。研究结果表明:随含水量增加,黏性土热导率与比热容显著增大,而热扩散系数变化幅度较小;当含水量达到阈值时,土颗粒间形成的连续“液体桥”使传热模式从颗粒接触传导转变为固-液复合传导;在含盐量影响分析中,Usowicz模型较其他模型更能准确表征黏性土热导率变化特征。研究成果可为黏性土地层地热资源开发及岩土工程热工设计提供理论支撑。
In the engineering context of geothermal resources development and utilization,the study on the evolution mechanism of thermal conductivity of soils is of significant guiding value for engineering practice.In this study,the thermal conductivity,thermal diffusion coefficient,and specific heat capacity of soil samples are measured under the varying conditions of water and salt content.The transient plane heat source method is employed to systematically reveal the evolution law of the thermophysical parameters of the soil and elucidate the thermal conductivity mechanism.This is achieved by examining the differences in heat transfer characteristics of the solid,liquid,and gas three-phase components.The applicability of the model to clayey soils is evaluated by comparing the fitting effects of three commonly used thermal conductivity models with the experimental data.The results of the study indicate that:it has been demonstrated that the thermal conductivity and specific heat capacity of clayey soil increase significantly with an increase in water content,while the change in the thermal diffusion coefficient is small;when the water content reaches a critical threshold,a continuous"liquid bridge"is formed between the soil particles,contributing to a change in the heat transfer mode from particle-to-particle conduction to solidliquid composite conduction;the Usowicz model is used to analyze the effect of salinity and to evaluate the heat transfer characteristics of the three-phase components.In the analysis,the said model exhibited superior capability in characterizing the change of thermal conductivity of clayey soil in comparison to alternative models.The findings of the study have the potential to furnish a theoretical framework conducive to the advancement of geothermal resource development and the conceptualization of geotechnical engineering thermal designs for clayey soil.
作者
陈琳
韩海龙
Chen Lin;Han Hailong(Beijing Delhi Technology Group Co.,Ltd.,Beijing 100025,China)
出处
《工程勘察》
2026年第2期55-60,共6页
Geotechnical Investigation & Surveying
关键词
黏性土
热导率
含水量
含盐量
导热路径
clayed soil
thermal conductivity
water content
salt content
thermal path
