孔径分布函数对水分在非饱和土体中迁移的作用（英文）

Role of the pore-size distribution function on water flow in unsaturated soil

目的:了解孔径分布函数对水分在非饱和土体中迁移的影响,并提出相关数学模型,量化非饱和土体在不同吸力作用下的渗透系数。创新点:从孔径分布函数出发探讨土体的工程性质,以日常生活中所用的阀门模型解释非饱和土体在不同吸力作用下的渗透系数。提出采用非饱和土渗透系数的实验数据,间接估算土体的孔径分布函数。方法:从物理模型推导相关数学公式,并用实验结果对数学公式进行验证。结论:孔径分布函数主导非饱和土的渗透系数;孔径分布函数是连接土体两大水力特性(包括水土特征曲线和渗流方程)的桥梁。孔径分布函数对水分在土体中迁移的作用可以用日常生活中使用的阀门模型简单描述。基于阀门模型,土体的孔径分布函数也可以由土体的非饱和渗透系数的相关实验数据间接估算得到。

The hydraulic properties of soil(i.e. soil-water characteristic curve(SWCC) and coefficient of permeability) govern the moisture flow in it. Previous research has indicated that the hydraulic properties of soil are dependent on its pore-size distribution. An improved capillary model is now proposed to explain the concept of the pore-size distribution in soil and its relationship to SWCC. A new model, the "valve model", is also proposed as the explanation for water flow in unsaturated soil. The pore-size distribution function is incorporated in the "valve model" and is used to calculate the relative coefficient of permeability for unsaturated soil. In this paper, the role of the pore-size distribution function in the estimation of SWCC and the permeability function are explained. Equations are proposed for estimating the pore-size distribution function from the experimental data of relative coefficient of permeability. The results from the proposed equations agree with the experimental data from laboratory measurement and published data.