一个冻土的渗透系数模型及其验证
New model for hydraulic conductivity of frozen soils
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摘要: 寒区冻胀、融沉等冻害的核心问题是水热耦合迁移过程,而冻土渗透系数的确定是研究这类问题的关键。不同于正温条件下土的渗透系数,冻土的渗透系数涉及液态水在土、冰两种固相物质内的流动机制。如何更精确、简洁地表达冻土的渗透系数,一直没有得到很好的解决。本文基于土中冰的赋存形态,结合正温渗透系数Kozeny-Carman方程推导过程,考虑冰颗粒的阻碍作用,提出一个新的冻土渗透系数模型。本文模型通过和文献中其他学者的模型以及试验数据的比较,可以较好地吻合试验数据,验证了本文模型的合理性。相较于既有的经验模型或复杂的数学模型,本模型只有一个拟合参数,形式简洁,有明确物理依据,具有一定的应用价值。Abstract: One of the core issues in studying the problems such as frost heave and thaw weakening in cold regions is the process of hydro-thermal coupling migration. Determination of the hydraulic conductivity of frozen soils is the critical point to understand this process. Different from that of soils at positive temperatures, the hydraulic conductivity of frozen soils involves the liquid water flow in soil grains and ice particles. How to better express the hydraulic conductivity of frozen soils is an outstanding issue in the literatures. In this study, a new hydraulic conductivity model for frozen soils is proposed on the basis of a derivation process of the Kozeny-Carman equation, which is consistent to the determination of hydraulic conductivity at positive temperatures. By comparing with the models in the literatures and experimental data, the model in this study can match the experimental data well, which verifies the rationality of the proposed model. Compared with the existing empirical models or the mathematical models in the literatures, this model has only one fitting parameter. Besides the proposed model has a clear physical basis and is simple in form, which is easy to apply.