A coupled model for liquid water-vapor-heat migration in freezing soils
A coupled model for liquid water-vapor-heat migration in freezing soils
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DOI：
10.1016/j.coldregions.2018.01.003
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发表时间：
2018-04-01
影响因子：
4.1
通讯作者：
Sheng, Daichao
中科院分区：
文献类型：
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作者：
He, Zuoyue;Zhang, Sheng;Sheng, Daichao
基于非饱和土力学中的渗流理论，建立了考虑气液相变和水冰相变的液态水-气-热耦合运移模型。对层状非饱和土的数值分析结果表明，蒸汽的迁移可导致总体积含水量的显着增加。总体积含水量的最大值的深度与冻结锋的深度（273.15K温度线）一致。地下水位对粉土总体积含水量的影响较小。然而，由于重力和基质势的作用，上层砂中的未冻水从砂向下流到粉土中。较低的上边界温度也会导致总体积含水量的明显增加。当上边界温度高于273.15K时，水汽运移对土柱的影响很小，仅使土柱总体积含水量增加2%。考虑到西北地区的实际工程应用，由于蒸汽迁移，高速铁路和机场的含水量也会显著增加。因此，在寒区和干旱区的实际工程中，应同时考虑液态水和水汽的保温措施。
Based on the seepage theory in unsaturated soil mechanics, a coupled model for liquid water-vapor-heat migration is established in this paper, which considers the phase changes of vapor-liquid and water-ice. The results of numerical analysis on layered unsaturated soils show that vapor migration can lead to a significant increase in the total volumetric water content. The depth of the maximum value of the total volumetric water content coincides with the depth of the freezing front (273.15K temperature line). Ground water table has a small effect on the total volumetric water content in silt. However, unfrozen water in the upper sand flows downward from the sand to the silt soil, due to gravitational and matric potentials. A lower temperature of the upper boundary can also lead to an apparent increase in the total volumetric water content. If the temperature of the upper boundary is above 273.15K, the effect of vapor migration on the soil column is small, producing only a 2% increase in the total volumetric water content. Considering actual engineering applications in the northwestern part of China, the water content of the embankments of high-speed railways and airports can also be increased significantly due to vapor migration. Therefore, both liquid water and vapor insulation countermeasures should be considered in practical engineering in frigid and arid regions.