The effect of horizontal freezing on the characteristics of water migration and matric suction in unsaturated silt
2021
Tang, Tianxiao | Shen, Yupeng | Liu, Xin | Zhang, Zhongqiong | Xu, Jiayi | Zhang, Zhicheng
Existing research on the mechanism of water migration during horizontal freezing is limited. Available freezing models are mainly applicable to saturated soils subjected vertical freezing and cannot accurately describe the coupled water-heat movement in unsaturated soils. In this paper, based on the Dallavalle formula and Young-Laplace equation, the Smith empirical formulation is used to establish a link between the macroscopic and microscopic water content of the frozen soil, and derive an analytical relationship between the matric suction and unfrozen water content of frozen soil. The formula is simplified to deduce the matric suction of unsaturated silt during horizontal freezing. A laboratory horizontal freezing experiment is carried out to explore the characteristics of the freezing process. The model established for the unsaturated freezing soil is subsequently improved by incorporating the relationships between matric suction, pore ice content, temperature, and unfrozen water content in the model. Using the model, the coupled water-heat movement during horizontal freezing process can be accurately described, and a typical case is analyzed to explore the interactions of temperature, unfrozen water, ice, and matric suction. In addition, the influence of the temperature gradient and initial water content on the freezing process characteristics is studied.
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