岩土工程学报2024，Vol.46Issue(7)：1408-1417,10.DOI:10.11779/CJGE20230473
碱-热条件下膨润土缓冲材料导热系数演化及微观特征
Microscopic analysis of thermal conductivity of bentonite as buffer materials under alkaline-thermal conditions
摘要
Abstract
The evolution characteristics of thermal conductivity of the bentonite as buffer layer materials under alkaline-thermal conditions are a key factor in the conceptual design of a deep geological repository for nuclear waste.The evolution laws of thermal conductivity of the bentonite buffer materials under alkaline-thermal conditions are investigated by using the thermal probe method for MX80 bentonite powder pretreated under different alkaline-thermal conditions.On this basis,the XRD,SEM,MIP and TGA tests are carried out on the representative specimens to reveal the mechanisms of alkaline-thermal effects on the evolution of mineral composition,microscopic morphology,pore structure and water-binding morphology of bentonite samples,and to further elucidate the microscopic mechanisms of the evolution of thermal conductivity of bentonite buffer materials under alkali-thermal conditions.The test results show that under alkali-thermal conditions,the thermal conductivity(λ)of the bentonite samples decreases with the increasing pH value of the alkaline solution and increases with the increasing ambient temperature(T).This characteristic is particularly significant in highly alkaline solutions(pH=13.0～14.0)and high temperature environments(T=60℃～90℃).The underlying cause is the dissolution of the original mineral components in the samples under the action of alkaline solution to varying degrees,as evidenced by the reduction in the contents of montmorillonite and quartz and the increase in the zeolite content,resulting in reduction in the solid content of the samples,increase in the porosity,and reduction in the dry density and water absorption properties,while the ambient temperature plays a good role in facilitating the process.关键词
膨润土缓冲材料/导热系数/碱-热条件/演化特征/微观机制Key words
bentonite buffer material/thermal conductivity/alkaline-thermal condition/evolution characteristic/micro-mechanism分类
建筑与水利引用本文复制引用
曾召田,林铭宇,孙德安,曹珊珊,车东泽,梁珍..碱-热条件下膨润土缓冲材料导热系数演化及微观特征[J].岩土工程学报,2024,46(7):1408-1417,10.基金项目
广西自然科学基金项目(2023GXNSFAA026187) （2023GXNSFAA026187）
国家自然科学基金项目(41962014,42167020) （41962014,42167020）
