Water and Salt Migration with Phase Change in Saline Soil during Freezing and Thawing Processes

• Published in: Ground water Vol. 56; no. 5; pp. 742 - 752
• Main Authors: Wu, Daoyong, Zhou, Xiangyang, Jiang, Xingyuan
• Format: Journal Article
• Language: English
• Published: Malden, US Blackwell Publishing Ltd 01.09.2018; Ground Water Publishing Company
• Subjects: Clay; Crystallization; Freeze-thaw; Freezing; Groundwater; Mass transfer; Melting; Migration; Moisture content; Phase change; Phase transitions; Saline soils; Salinization; Salt; Salts; Soil; Soil properties; Soil salinity; Soil salinization; Soil structure; Soil surfaces; Soil temperature; Structural damage; Temperature; Thawing; Water; Water content
• ISSN: 0017-467X; 1745-6584
• DOI: 10.1111/gwat.12605

Water and salt transfer coupled with phase change may cause serious damage to engineering structures in saline soil regions. In this study, the migration of water and salt in silty clay collected from the Qinghai‐Tibet Plateau is explored experimentally and numerically during freezing and thawing processes. The results revealed that there are significant differences in the variations of liquid water content and solution concentration for different initial salt contents, due to salt crystallization and dissolution. The temperature‐induced water migration is determined by the soil properties, which can be well explained by the thermodynamics of mass transfer. The amount of salt migrated upward during cooling is slightly larger than that transported downward in the warming period, implying that salt may be accumulated in the surface soil after a large number of circulations and finally result in soil salinization. Article impact statement: Water and salt transfer with phase change in saline soil was studied experimentally, and the mechanism of soil salinization was explored.