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.