土壤颗粒尺寸分布分维及对粘附行为的影响

依据Tyler和Wheatcraft推导的土壤颗粒累积质量—尺寸标度关系,计算了我国主要土壤的颗粒尺寸分布(PSD)分维,结果表明:淡栗钙土、黄绵土、黑垆土、褐土((土娄)土)、潮土、灰漠土、黑土、黄棕壤、黄壤、红壤及赤红壤(砖红壤)的PSD分维依次增大,土壤粘粒含量增加使其PSD分维增大。结合上壤颗粒表面分形特性及土壤粘附的基本原理,探讨了土壤PSD分维对土壤—固体表面粘附行为的影响。PSD分维高的土壤与固体表面粘附力大,与固体表面发生明显粘附的起始含水量提高,发生明显粘附的含水量区间增宽。

Fractal Dimensions of Soil Particle-Size Distributions and Their Effects on Soil Adhesion Behaviour

Fractal dimensions of particle-size distributions (PSD) of major soils in China were examined based on the cumulative mass-size relation given by Tyler and Wheatcraft. The results show that the PSD fractal dimension of Light chestnut soil, Yellow cultivated loessial soil, Orthic dark locssial soil, Orthic cinnamon soil (stratified old manured loessial soil), Fluvo-aquic soil, Orthic gray desert soil, Orthic black soil, Orthic yellow-brown earth, Orthic yellow earth, Orthic ted earth and Orthic lateritic red earth (Orthic latosol) increases in sequence. Fractal characteristics of soil particle surfaces and the basic principles of soil adhesion against solid surfaces were considered and then the effects of fractal dimensions of soil PSD on soil adhesion behaviour were discussed. As fractal dimensions of soil PSD increase, the plastic limit, liquid limit and plasticity index of soil were elevated; the moisture content at which soil adhesion occures and the range of moisture content at which soil adhesion phenomenon exists becomes larger and the soil adhesion force is increased ?Soils possessing higher surface fractal dimesions may have higher adhesion force on solid surfaces.