Fractal models for the soil-water characteristics of unsaturated soils

Fractal models for the soil-water characteristics were categorized into three groups:fractal model for soil mass distribution,fractal model for pore surface and fractal model for pore volume-size distribution.A general expression of the soil-water characteristics was proposed based on the fractal model for the pore volume-size distribution.The proposed general expression of the soil-water characteristics gave out a good result at water contents close to saturation and at very low water content,and can evaluate both the drying and wetting curves of the soil-water characteristics using the same fractal dimension.