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土水特征曲线是非饱和土的一个重要的本构特性。它对于研究非饱和土的物理力学特性至关重要,同时也是非饱和土动态水力分析的一个必要条件。长期以来对这一特性的理论解释一直是对研究者的一个挑战。由于岩土内部结构的复杂多变性,而非饱和土的含水状态又涉及到许多物理及化学的影响因素,至今还未能有一个圆满的数学模型在描述这一特性时能够全面概括这些机理。首先综述了目前国际上的主要研究成果。之后,在传统的孔隙介质分析方法的基础上,利用现代表面科学的理论,分析并存于非饱和土孔隙中的水、汽两相的物理化学行为,最后利用平均理论推导出一个宏观尺度下的土水特征曲线的理论表达式。这一理论表达式揭示了土水特征曲线背后的物理化学机理,对该表达式的数学分析发现它能够很好地解释实验中所观察到的现象。最后根据这一理论表达式,提出了一个简化的土水特征曲线拟合模型。通过对多种土壤以及其他孔隙材料的实验结果的模拟证明这一模型不仅能非常好地拟合实验结果,而且优于其它现有的主要模型。
The soil-water characteristic curve is an important constitutive characteristic of unsaturated soils. It is very important for studying the physical and mechanical properties of unsaturated soils, and it is also a necessary condition for dynamic hydraulic analysis of unsaturated soils. The theoretical explanation for this feature has long been a challenge for researchers. Due to the complex variability of geotechnical internal structures, the water-bearing state of unsaturated soils involves many physical and chemical influence factors. To date, there has not been a complete mathematical model that can fully summarize these mechanisms when describing this characteristic. First, it summarizes the major international research results. Afterwards, based on the traditional method of pore media analysis, the theory of modern surface science was used to analyze the physical and chemical behaviors of water and gas phases that existed in the pores of unsaturated soils. Finally, an average theory was used to derive a macroscopic scale. The theoretical expression of the soil-water characteristic curve. This theoretical expression reveals the physicochemical mechanism behind the soil-water characteristic curve. Mathematical analysis of this expression has found that it can well explain the phenomena observed in the experiment. Finally, based on this theoretical expression, a simplified soil-water characteristic curve fitting model was proposed. Simulations of the experimental results for a variety of soils and other porous materials demonstrate that this model not only fits the experimental results very well, but is also superior to other existing major models.