考虑有机质含量及分解度的草炭土导热系数模型改进  

Improvement of the thermal conductivity model for turfy soil in view oforganic matter content and decomposition degree

作　　者：贺元源 何玟 王力[1,2] 王世梅[1,2] 吕岩[3] 徐燕[3] 陈勇[1,2] 张先伟[4] HE Yuanyuan;HE Wen;WANG Li;WANG Shimei;LYU Yan;XU Yan;CHEN Yong;ZHANG Xianwei(Key Laboratory of Geological Hazards on Three Gorges Reservoir Area(China Three Gorges University),Ministry of Education,Yichang 443002,China;College of Civil Engineering&Architecture,China Three Gorges University,Yichang 443002,China;College of Construction Engineering,Jilin University,Changchun 130026,China;State Key Laboratory of Rock and Soil Mechanics and Engineering,Wuhan Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China)

机构地区：[1]三峡大学三峡库区地质灾害教育部重点实验室,宜昌443002 [2]三峡大学土木与建筑学院,宜昌443002 [3]吉林大学建设工程学院,长春130026 [4]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,武汉430071

出　　处：《农业工程学报》2024年第20期120-128,共9页Transactions of the Chinese Society of Agricultural Engineering

基　　金：三峡库区地质灾害教育部重点实验室(三峡大学)开放研究基金项目(2023KDZ10);湖北省自然科学基金青年项目(2024AFB082);国家自然科学基金重点项目(U21A2031);防灾减灾湖北省重点实验室(三峡大学)开放基金课题(2023KJZ23)。

摘　　要：土壤导热系数是决定土层传热性能的主要参数,影响到地温分布、土壤环境及作物生长。高有机质土的导热系数受到有机质组分直接影响,而目前土壤导热系数模型缺乏对有机质含量及分解度的考虑。该研究采用稳态比较法测定了未冻结及冻结状态下的草炭土导热系数,分析了不同层位原状草炭土性质对导热系数的影响,对比了10余种土体导热系数计算模型对草炭土的适用性,并以此提出了改进模型。结果表明:1)各层位草炭土在未冻结状态下导热系数相近(0.51~0.66 W/(m·K)),而冻结后导热系数层间差异明显(1.00~1.62 W/(m·K)),表明冻结极大地改变了土体物质组成,而有机质含量及分解度显著影响着土体的传热性质;2)考虑了干密度及组分权重的土体导热系数模型对草炭土的预测适用性更佳,但准确度仍然难以达到理想效果;3)基于土体性质的影响程度及计算模型的原理,引入草炭土有机质含量O_(c)及分解度D_(d)计算草炭土导热系数,建立了改进模型,提高了参数模型准确率(R^(2)>0.75)。研究成果可为季冻草炭土分布区的农业耕作及工程建设提供参数依据,同时可作为高有机质土体热物理性质研究的理论参考。Soil thermal conductivity is one of the most important parameters to determine the heat transfer performance of the soil layer,leading to the ground temperature distribution,soil environment,and crop growth.The composition of organic matter is directly related to the thermal conductivity of high organic soil.However,the current model of soil thermal conductivity cannot consider the organic matter content and decomposition degree.This study aims to analyze the influence of the undisturbed turfy soil on the thermal conductivity in the different layers.Additionally,more than 10 improved models of soil thermal conductivity were proposed and then compared on the turfy soil.The results indicate that:1)The thermal conductivity in each layer of unfrozen turfy soil was similar(0.51~0.66 W/(m∙K)).There was a significant difference in the thermal conductivity among the layers(1.00-1.62 W/(m∙K))after freezing,indicating that the freezing altered the composition of the soil.The higher proportion of components was found with the low heat transfer performance,due to more organic matter components and pores in turfy soil.The thermal conductivity of unfrozen turfy soil was lower than that of other organic soil with higher dry density.Most water in the soil was turned into ice after freezing,indicating the greatly improved thermal conductivity.The high content of water greatly contributed to the thermal conductivity of frozen turfy soil.Furthermore,a correlation analysis was carried out between the fundamental physical properties of turfy soil and the thermal conductivity.The soil particle size distribution,organic matter content,and decomposition degree depended mainly on the thermal conductivity of unfrozen turfy soil.2)Most prediction models of soil thermal conductivity(Campbell,Johansen,and their derived models)failed to directly consider the proportion of organic matter components in the turfy soil,leading to overestimation of the thermal conductivity of organic matter in the solid phase.Alternatively,the soil thermal con

关 键 词：土壤 模型 导热系数 有机质含量 分解度 草炭土 

分 类 号：S15[农业科学—土壤学]