摘要
开展考虑温度影响的盐溶液入渗膨润土膨胀变形特性研究,对于高放废物深地质处置库的设计与安全运营具有重要意义。以高庙子膨润土为研究对象,开展了不同温度条件下NaCl和CaCl2溶液饱和的一维膨胀变形试验,分析了温度和盐溶液浓度对膨胀变形的影响;结合压汞试验和扫描电镜试验,揭示了温度和盐溶液对膨胀变形影响的微观机理。结果表明:温度和盐溶液浓度升高,达到最大膨胀应变时间缩短,最大膨胀应变减小。盐溶液浓度升高,扩散双电层厚度减小,渗透吸力和有效应力增大;同时,温度升高,集合体间孔隙收缩和晶格收缩,抑制扩散双层膨胀,导致集合体间孔隙的孔径密度降低,集合体间孔隙在水化过程中被填充堵塞,试样膨胀性能减小。在此基础上,建立了考虑温度影响的盐溶液入渗膨胀变形时程曲线模型。
Investigation on swelling deformation of bentonite infiltrated with salt solutions considering temperature effects is of great significance for design and safely operation of deep geological repositories for disposal of high-level radioactive wastes.In this study,one dimensional deformation tests are performed on GMZ bentonite specimens with infiltration of NaCl and CaCl2 solutions at different temperatures.Coupled temperature and salt solution effects on the swelling deformation properties are investigated.Meanwhile,MIP tests and SEM tests are performed to find out the micro-mechanism of the effects of temperature and salt solution on swelling deformation.Results indicate that the time to reach the maximum swelling strain is reduced and the maximum swelling strain decreases with increasing temperature and concentrations.In high concentration of salt solutions,the thickness of the diffuse double layers decreases,the osmotic suction and effective stress increase;meanwhile,the increase of temperature causes the shrinkage of inter-aggregate pores and the lattice contraction,and also inhibits the expansion of the diffuse double layers.As a result,the pore density of inter-aggregate pores decreases,the inter-aggregate pores are filled and blocked during the hydration process,and the swelling capacity of bentonite decreases.Finally,a model for the time-evolution curve of swelling deformation considering temperature and concentration of salt solution is proposed.
作者
叶为民
邵长跃
王琼
陈永贵
陈亮
YE Weimin;SHAO Changyue;WANG Qiong;CHEN Yonggui;CHEN Liang(Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji University,Shanghai 200092,China;Beijing Research Institute of Uranium Geology,Beijing 100029,China)
出处
《岩土工程学报》
北大核心
2025年第11期2237-2245,共9页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(42030714)。
关键词
高庙子膨润土
膨胀变形
盐溶液
温度
微观结构
模型
GMZ bentonite
swelling deformation
salt solution
temperature
micro-structure
model
