游离氧化铁赋存形式对脱吸湿条件下红黏土热传导性能的影响  

Effects of occurrence form of free iron oxide on thermal conductivity of lateritic clay during drying and wetting conditions

作　　者：徐云山 肖子龙 孙德安[2] 李建平 XU Yunshan;XIAO Zilong;SUN Dean;LI Jianping(Key Laboratory of Underground Engineering of Fujian Provincial Universities,Fujian University of Technology,Fuzhou 350118,China;Department of Civil Engineering,Shanghai University,Shanghai 200444,China)

机构地区：[1]福建理工大学地下工程福建省高校重点实验室,福建福州350108 [2]上海大学土木工程系,上海200444

出　　处：《岩土工程学报》2025年第4期811-819,共9页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(42202295,42207230);福建省自然科学基金项目(2021J05219)。

摘　　要：游离氧化铁赋存形式对红黏土热传导性能的影响尚不清楚。利用热探针法对去除游离氧化铁前后原状和压实样的热传导性能进行测试,并结合红黏土在脱、吸湿条件下微观结构特征的演化,探讨了游离氧化铁和制样方式对其热传导性能的影响机制。热传导性能试验结果表明,相同含水率下压实红黏土的热传导系数小于原状样,平均约小4.8%。同条件下去铁后原状样的热传导系数比未去铁试样平均高约29.3%,去除游离氧化铁后原状样的热传导系数在含水率变化曲线上呈现滞回减弱现象。微观试验结果表明,去铁后原状试样的孔隙数量明显少于未去铁试样,未去铁原状样存在少量孔径约为10μm的较大孔隙,去除游离氧化铁后原状样中较大的孔隙基本上消失。游离氧化铁对红黏土试样热传导性能的影响机制可理解为,游离氧化铁以“包膜”“桥接”和“附着”形式将土粒或团聚体集聚胶结起来,去铁后,部分较大团聚体分散为较小团聚体或土粒,充填土中较大孔隙,从而增加土颗粒间的接触与传热路径。The influences of occurrence form of free iron oxide(FIO)on the thermal conductivity of lateritic clay are still unclear.In this study,the thermal probe method is used to measure the thermal conductivity(TC)of undisturbed and compacted specimens before and after removing FIO.Combined with the evolution of microstructural characteristics,the influence mechanism of FIO and the specimen preparation method on TC is investigated.The thermal conductivity test results show that the TC of compacted specimens is lower than that of undisturbed specimens(US)under the same water content,with an average decrease of about 4.8%.After removing FIO,the TC of the US significantly increases,with an average increase of about 29.3%.Moreover,the hysteresis phenomenon between the TC and the volumetric water content of US after FIO removal is weakened.The microscopic test results show that the pore number in US after FIO removal is significantly less than that in untreated specimens.There are a small number of larger pores with a pore size of~10μm in US without FIO removal.The larger pores are basically eliminated in US after FIO removal.The mechanism by which FIO affects the TC of lateritic clay can be understood as:FIO can aggregate and bond soil particles or aggregates in the form of"encapsulation","bridging",and"attachment".After removing FIO,some larger aggregates are dispersed into smaller aggregates or soil particles,which in turn fill the larger pores,increasing the contact and heat transfer paths between soil particles.

关 键 词：红黏土 游离氧化铁 赋存形式 热传导性能 土体微观结构 

分 类 号：TU43[建筑科学—岩土工程]