冻融过程土壤水热力耦合作用及其模型研究进展

Review of the coupling of water and heat in the freeze-thaw process and its model of frozen soil

冻融过程水热力耦合是寒区水文循环的重要内容,是寒区农业、建筑、生态领域需要迫切解决的问题。本研究对冻土冻融过程、水热力耦合机理研究进行了分析:目前对于水分迁移驱动力大多归结于土壤水势梯度,采用土壤水分特征曲线进行求解,但是这种方法并没有考虑土体温度、土体形变以及土壤的物理特性指标。水热力耦合模型实现了水分、温度、应力之间的耦合,但是水分、温度、应力的变化对土壤特征参数的反馈机制并未体现;在多场作用下的分凝冰形成机理是解决土体冻胀的关键,对该问题有待进行深入研究。同时对目前主流的水动力学模型、刚性冰模型、热力学模型3类耦合模型在适用性和准确性方面进行了讨论。最后,针对目前冻融过程水热力耦合研究存在的问题进行分析并提出研究的构想。

The coupling of water and heat in the freeze-thaw process is an important part of the hydrological cycle in cold regions,and it is an urgent problem that needs to be solved in the fields of agriculture,construction,and ecology in cold regions.We analyzed the freezing-thawing process of frozen soils and water-thermal coupling mechanism.At present,the driving force of water migration is mostly attributed to the soil water potential gradient,with the soil water characteristic curve used to solve the problem.However,this method does not consider the soil temperature,deformation,and physical properties.The hydrothermal coupling model achieves the coupling between water,temperature,and stress,but the feedback mechanisms of the changes in water,temperature,and stress on the soil characteristic parameters are not reflected.The mechanism for ice formation,under the action of multiple fields,is the key to solve the problem of soil frost heave.Meanwhile,we discussed the applicability and accuracy of the three types of current mainstream coupling models:The hydrodynamic,rigid ice,and thermodynamic models.Finally,we analyzed the current problems in the study of hydrothermal coupling in the freeze-thaw process.