中文摘要：

土壤粒径分布是影响土壤水力特性最基本的土壤物理性质之一．为定量描述壤土粒径分布的非均匀特性，应用激光粒度仪对6个典型壤土土样测定了土壤颗粒的等效直径和分布规律，运用分形和多重分形理论描述了土壤粒径分布的非均匀性，计算了粒径分布的分形维数口和奇异性指数α及其相应的谱函数f（α），得到了壤土粒径分布的分形维数和多重分形谱曲线．结果表明：壤土的粒径分布具有分形和多重分形特征，单分形只能描述土壤粒径分布的整体特征，多重分形谱宽度△α定量表征了土壤粒径分布的非均匀程度，△α愈大，粒径分布愈不均匀；壤土粒径分布的非均匀程度受土壤中粘粒和砂粒含量的影响．多重分形方法为土壤粒径分布非均匀性的定量研究提供了一种精确的分析方法．

英文摘要：

Soil particle size distribution is one of the fundamental soil physical properties affected soil hydraulic properties. In order to quantitatively describe the heterogeneity of loamy soil particle size distribution, the technology of laser grain-size analysis was applied to measure the equivalent diameter and particle size distribution of six loamy soil samples, and the heterogeneity characteristics of soil particle size distribution was analyzed with fractal and multifractal theory, the fractal dimensions D, muhifractal parameters as singularity index ot and its corresponding spectral function f（α） was calculated, therefore, the fractal dimensions and the muhifractal spectra curves of soil samples were obtained. The results showed that： the particle size distribution of loamy soil exhibits fractal and muhifractal characteristics, and the fractal can only describe the whole characteristics of the soil paticle size distribution, but the heterogeneity of soil particle size distribution can be described quantitatively by the width of muhifractal spectra △α, a greater △α means a wider spectra and more heterogeneous distribution on the particle size, and the heterogeneity of loamy soil particle size distribution offected by clay and sand-grain content. The multifractal provides an accurate analysis method to quantitatively study the heterogeneity of soil particle size distribution.