Abstract

In order to study the relationship between multifractal characteristics of particle-size distribution (PSD) and unsaturated hydraulic conductivity, taking the Hunan clay as the research object, we analysed the particle composition of the whole particle size range by a laser particle size analyser, and discussed the multifractal characteristics of PSD by using the fractal theory. The soil–water characteristic curve (SWCC) and unsaturated hydraulic conductivity were measured by the pressure plate instrument and instantaneous profile method, and the unsaturated hydraulic conductivity was predicted by the fractal model. The results show that the fractal dimension D is not a fixed value for the Hunan clay with the whole particle size range, which exhibits obvious multifractal characteristics. The value of fractal dimension D is closely related to the investigated particle size range. The larger the particles in the particle size range, the larger the corresponding fractal dimension D. By comparing the measured and predicted values of the unsaturated hydraulic conductivity, it is found that the prediction results of fractal dimension D for unsaturated hydraulic conductivity with different particle size ranges are quite different, and that those results with larger particle size ranges are more reasonable.

摘要

为研究粒度分布（PSD）的多重分形特征与非饱和导水率的关系，以湖南黏土为研究对象，采用激光粒度分析仪分析了整个粒度范围内的颗粒组成，并利用分形理论讨论了PSD的多重分形特征。土水特征曲线（SWCC）和非饱和导水率采用压力板仪和瞬时剖面法进行测量，非饱和导水率采用分形模型进行预测。结果表明，分形维数D对于全粒径范围的湖南黏土来说不是一个固定值，呈现出明显的多重分形特征。分形维数D的值与所研究的粒径范围密切相关。粒径范围内的颗粒越大，对应的分形维数D越大。通过比较非饱和导水率的实测值和预测值，发现不同粒径范围的不饱和导水率的分形维数D的预测结果存在较大差异，粒径范围较大的结果更合理。