| 季节冻土区水盐迁移及土体变形特性模型试验研究 |
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| 引用本文： | 吴道勇,赖远明,马勤国,王 冲.季节冻土区水盐迁移及土体变形特性模型试验研究[J].岩土力学,2016,37(2):465-476. |
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| 作者姓名： | 吴道勇 赖远明 马勤国 王 冲 |
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| 作者单位： | 1.中国科学院寒区旱区环境与工程研究所 冻土工程国家重点实验室，甘肃 兰州 730000； 2.中国科学院大学，北京 100049；3.兰州大学 土木工程与力学学院，甘肃 兰州 730000 |
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| 基金项目： | 国家自然科学基金重点资助项目（No.41230630）；中国科学院西部行动计划项目（No. KZCX2-XB3-19）；国家重点基础研究计划（973）项目（No. 2012CB026102）。 |
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| 摘 要： | 为研究盐渍化冻土水分、盐分迁移规律以及变形特性，探索寒区旱区土壤盐渍化机制，配制了不同含盐量的粉质黏土进行模型试验。试验结果表明，温度、水分、盐分和土体变形之间相互耦合。温度降低有利于盐晶体析出和未冻水结冰；反之，温度升高易于晶体溶解和冰融化。水盐相变过程中伴随能量的释放或吸收，影响土体温度。盐分改变了流体的动力黏度和土体冻结温度，并且盐分结晶使土体产生较大的吸力，加剧了未冻水含量的变化。水分是盐分迁移的介质，盐分以离子形式随未冻水迁移。降温期水分盐分向上迁移，升温期迁移方向相反。迁移速率与吸力有关，冻结缘附近吸力最大，速率最快。盐渍化冻土的变形是盐分和水分共同作用的结果，含盐量较低时冻胀和融沉是土体变形的主要因素；当含盐量较高时盐胀和溶陷占主导作用。
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| 关 键 词： | 季节冻土 盐分迁移 变形特性 模型试验 |
| 收稿时间： | 2015-05-25 |
Model test study of water and salt migration and deformation characteristics in seasonally frozen soil |
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| WU Dao-yong,LAI Yuan-ming,MA Qin-guo,WANG Chong.Model test study of water and salt migration and deformation characteristics in seasonally frozen soil[J].Rock and Soil Mechanics,2016,37(2):465-476. |
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| Authors: | WU Dao-yong LAI Yuan-ming MA Qin-guo WANG Chong |
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| Institution: | 1. State Key Laboratory of Frozen Soil Engineering, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China; 2. University of Chinese Academy of Sciences, Beijing 100049, China; 3. School of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000, China |
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| Abstract: | In order to investigate the law of water and salt migration, understand the deformation characteristics of saline frozen soil, and explore the mechanism of soil salinization in cold and arid regions, a model test of silty clay with different salinities is carried out. Results indicate that the temperature, water, salt and deformation of the saline frozen soil are coupling with each other. The temperature reduction is advantageous to precipitate the salt crystals and freeze the unfrozen water, while the temperature rise is liable to dissolve the salt crystals and thaw the ice. Heat release or absorption during the phase change of salt and water influences the soil temperature. Salt influences the water content significantly by changing the dynamic viscosity of the fluid and freezing temperature the soil, and generating a great suction when salt crystals precipitate from the supersaturated solution. Salt migrating with unfrozen water in ionic form means that water is the medium for salt migration. Salt and water are moving upward to the surface during cooling period, while the opposite direction is observed during warming period. The migration rate is related to the soil suction, and the greatest soil suction in the freezing fringe results in the fastest migration velocity. The deformation of saline frozen soil is the result of the combined effect of salt and water. Frost heave and thaw settlement caused by water freezing and thawing are the mainly deformation of saline frozen soil with low salinity, while salt heave and dissolve settlement caused by salt crystallization and dissolution play the dominant role with high salinity. |
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| Keywords: | seasonally frozen soil salt migration deformation characteristics model test |
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