模拟非饱和流的新型相对渗透系数模型

A Relative Permeability Model for Unsaturated Flow in Consideration of Hysteresis Effect

相对渗透系数是非饱和土渗流特性研究普遍关注的重要内容。依据非饱和土体渗流滞后效应机理,考虑土体孔隙不均匀性引起滞后效应问题,采用分形理论和白汉金-达西定律,构建了能够反映非饱和流滞后效应的土-水特征曲线模型,并在此基础上导出了一个新型的非饱和流相对渗透系数模型。所提出的模型形式简单,仅包含1个参数。结合5组代表性的相对渗透系数试验数据,验证了所提出的模型的合理性,并与Assouline模型比较,结果表明所提出的模型拟合结果整体上要优于Assouline模型。

Relative permeability coefficient is an important content in the study of seepage characteristics of unsaturated soils.In consideration of the hysteresis effect of unsaturated soil seepage caused by the non-uniformity of soil pores,a soil-water characteristic curve(SWCC)model reflecting the hysteresis effect of unsaturated flow is constructed by using the fractal theory and the Buckingham-Darcy law.On such basis,a model of relative permeability coefficient of unsaturated flow is derived.The proposed model is simple in form and contains only one parameter.The rationality of the model proposed in this paper is verified by five representative sets of test data of relative permeability coefficient.Compared with the Assouline model,the proposed model has superior fitting results.