摘要
为探究冻融循环作用下岩石孔隙结构的细微观演化规律,借助电镜扫描仪、核磁共振系统开展了一系列冻融循环试验。结果表明,当冻融次数大于60次时,中孔区域围成的T2谱面积逐渐增大;当冻融次数增至120次时,由于冻结力作用造成的结构劣化损伤不可逆,T2谱右峰面积较其他工况显著增加,孔隙度逐渐增大,并呈幂指函数形式增加。在水分迁移和结晶膨胀作用影响下,岩石中微孔扩展贯通,小孔隙结构不断演变为中孔和大孔结构。孔隙结构分维值与冻融循环次数呈负相关关系,孔喉分形结果的相关性高于孔径。研究结果有助于理解寒区环境下工程岩体冻胀开裂、冻融滑塌等作用机制。
In order to explore the microscopic evolution laws of rock pore structure under freeze-thaw cycles,a series of freezethaw cycle tests were carried out by means of electron microscope scanner and nuclear magnetic resonance system.The results show that when the number of freeze-thaw cycles is more than 60times,the T2spectrum area enclosed by the mesopore region gradually increases.When the number of freeze-thaw cycles increases to 120times,the structural deterioration damage caused by the freezing force is irreversible.The right peak area of T2spectrum increases significantly compared with that in other working conditions,and the porosity gradually increases with a power exponential function.The micropores in the rock expand and penetrate due to the influences of water migration and crystallization expansion,and the small pore structure continues to evolve into the mesopores and macropores.The fractal dimension of pore structure is negatively correlated with the number of freeze-thaw cycles,and the correlation of pore throat fractal results is higher than that of pore diameter.The results are helpful to understand the mechanism of frost heave cracking and freeze-thaw collapse of engineering rock mass in cold region.
作者
覃祖淼
雷瑞德
QIN Zumiao;LEI Ruide(AVIC Institute of Geotechnical Engineering Co.,Ltd.,Beijing 100098,China;College of Civil Engineering,Sichuan University of Science&Engineering,Zigong,Sichuan 643000,China;Key Laboratory of Bridge Nondestructive Testing and Engineering Calculation in Sichuan Provincial Universities,Zigong,Sichuan 643000,China)
出处
《矿业研究与开发》
CAS
北大核心
2023年第8期132-138,共7页
Mining Research and Development
基金
四川省自然科学基金项目(2022NSFSC1033)
桥梁无损检测与工程计算四川省高校重点实验室开放课题基金资助项目(2022QZJ01)。
关键词
砂岩
冻融循环
孔隙结构
细观劣化
Sandstone
Freeze-thaw cycle
Pore structure
Mesoscopic deterioration
