| 引用本文: | 石亚军,马巍,杨成松,张莲海,尚飞,陈橙.冻融条件下粉质黏土中吸附水和自由水动态变化规律[J].哈尔滨工业大学学报,2024,56(3):89.DOI:10.11918/202302001 |
| SHI Yajun,MA Wei,YANG Chengsong,ZHANG Lianhai,SHANG Fei,CHEN Cheng.Dynamic change characteristics of adsorbed and free water in silty clay under freezing-thawing conditions[J].Journal of Harbin Institute of Technology,2024,56(3):89.DOI:10.11918/202302001 |
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| 冻融条件下粉质黏土中吸附水和自由水动态变化规律 |
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石亚军1,2,马巍1,2,杨成松1,张莲海1,3,尚飞1,2,陈橙1,2
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(1.冻土工程国家重点实验室(中国科学院西北生态环境资源研究院),兰州 730000; 2.中国科学院大学,北京 100049; 3.磁共振冻土成冰过程动态分析联合实验室,兰州 730000)
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| 摘要: |
| 为了研究粉质黏土中吸附水和自由水在冻融时的动态变化特征,探索土体冻融过程中土水之间物理过程。采用新型分层核磁测量技术,开展了含水量（质量分数）分别为21.1%,16.8%和12.0%的粉质黏土在封闭条件下的冻融试验,并采用电子显微镜扫描了冻融后不同深度土体的微观结构。试验结果表明:随着土体冻结过程持续,不同深度土体中自由水和吸附水均减少,且冻结区和非冻结区的自由水相对减少量均大于吸附水相对减少量；土样融化时不同深度土体中自由水和吸附水均增加；此外冻融作用导致冻结区吸附水减少,自由水增加；而未冻结区的吸附水和自由水均减少；冻融后冻结区的孔隙数量和孔隙体积增加,而未冻结区孔隙数量和孔隙体积减小。冻结过程中土体吸附水和自由水动态变化差异与水分子作用势的不均匀空间分布有关；冻融前后土体吸附水和自由水的重分布是水分迁移和土体微观结构变化共同作用的结果。 |
| 关键词: 冻土 吸附水 自由水 冻融 核磁共振 |
| DOI：10.11918/202302001 |
| 分类号:P642.14 |
| 文献标识码:A |
| 基金项目:国家自然科学基金重点项目(41630636)；国家自然科学基金青年科学基金项目(41501072)；冻土工程国家重点实验室自主课题(SKLFSE-ZT-202107) |
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| Dynamic change characteristics of adsorbed and free water in silty clay under freezing-thawing conditions |
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SHI Yajun1,2,MA Wei1,2,YANG Chengsong1,ZHANG Lianhai1,3,SHANG Fei1,2,CHEN Cheng1,2
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(1.State Key Laboratory of Frozen Soil Engineering (Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences), Lanzhou 730000, China; 2.University of Chinese Academy of Sciences, Beijing 100049, China; 3.Joint NMR Laboratory for Freeze-Thaw Processes in Soils, Lanzhou 730000, China)
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| Abstract: |
| To investigate the dynamic characteristics of adsorbed water and free water in silty clay during freezing and thawing and explore the physical processes between soil and water during these processes, a novel layered nuclear magnetic measurement technique was employed. Freezing-thawing experiments were conducted under closed conditions on silty clay with water contents (mass fractions) of 21.1%, 16.8%, and 12.0%, respectively. The microstructure of the soil at different depths after freezing and thawing was scanned using an electron microscope. The experimental results indicate that as the soil freezing process continues, both adsorbed water and free water decrease at different soil depths, and the relative decrease in free water is greater than that of adsorbed water in both the frozen and unfrozen zones. During thawing, both adsorbed water and free water increase at different soil depths. Furthermore, freezing and thawing lead to a decrease in adsorbed water and an increase in free water in the frozen zone, while both adsorbed water and free water decrease in the unfrozen zone. After freezing and thawing, the number and volume of pores increase in the frozen zone, while they decrease in the unfrozen zone. The dynamic differences in adsorbed water and free water during freezing are related to the inhomogeneous spatial distribution of water molecule interaction potential. The redistribution of adsorbed water and free water in the soil before and after freezing-thawing is the result of the combined effects of water migration and changes in soil microstructure. |
| Key words: frozen soil adsorbed water free water freezing-thawing action nuclear magnetic resonance |
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