A Tensorial Connectivity–Tortuosity Concept to Describe the Unsaturated Hydraulic Properties of Anisotropic Soils
A Tensorial Connectivity–Tortuosity Concept to Describe the Unsaturated Hydraulic Properties of Anisotropic Soils
复制标题
描述各向异性土壤不饱和水力特性的张量连通性-曲折度概念
DOI：
10.2136/vzj2003.3130
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
G. Gee
中科院分区：
文献类型：
--
作者：
Z. Zhang;A. Ward;G. Gee
非饱和导水率的各向异性与饱和度有关。然而，在自然土壤中模拟这种现象的选择寥寥无几。提出了描述非饱和土壤导水率的张量连通性-曲折度(TCT)概念。TCT概念假定土壤孔隙连通性和/或曲折性是各向异性的，可以用张量来描述。通过引入连接性张量，与饱和度相关的各向异性可以很容易地在相对渗透率的常见模型中被引用。通过允许饱和导水率对不同的水流方向有不同的相关范围，定义了具有假设各向异性的合成米勒相似土。利用具有四个非均质性和四个各向异性的合成土壤对TCT概念进行了检验。结果表明，土壤持水曲线与水流方向无关，但与土壤非均质性有关，而连通曲折系数是土壤非均质性和各向异性的函数。TCT模型可以准确地描述各向异性土的非饱和水力函数，并且可以很容易地与常用的相对渗透率函数相结合，用于流动方程的数值求解。
The anisotropy in unsaturated hydraulic conductivity is saturation dependent. Yet, there are few options for modeling this phenomenon in natural soils. A tensorial connectivity–tortuosity (TCT) concept is proposed to describe the unsaturated soil hydraulic conductivity. The TCT concept assumes that soil pore connectivity and/or tortuosity are anisotropic and can be described using a tensor. Saturation‐dependent anisotropy can be easily invoked in common models of relative permeability by incorporating the connectivity tensor. Synthetic Miller‐similar soils having hypothetical anisotropy are defined by allowing the saturated hydraulic conductivity to have different correlation range for different directions of flow. The TCT concept was tested using the synthetic soils with four levels of heterogeneity and four levels of anisotropy. The results show that the soil water retention curves were independent of flow direction but dependent on soil heterogeneity, while the connectivity–tortuosity coefficient is a function of both soil heterogeneity and anisotropy. The TCT model can accurately describe the unsaturated hydraulic functions of anisotropic soils and can be easily combined with commonly used relative permeability functions for use in numerical solutions of the flow equation.