In order to establish a fitting approach for soil-water characteristic curves (SWCC) with clear physical meanings

a method is presented to directly calculate the fractal dimensions through the SWCC data based on the fractal theory

and a fractal model of SWCC is proposed. To verify the proposed fitting method

seven clay samples with different dry densities are prepared using hydraulic jacks

and the soil-water characteristic curves are measured by using the pressure plate apparatus. Based on the experimental results of SWCC

the fractal dimensions are calculated. On this basis

fitting analysis of the SWCC data is performed by using the presented method. The results show that

all the correlation coefficients of the seven samples range from 0.97 to 0.99

which indicates good fractal characteristics of SWCC as well as good fitting performance of the proposed method. In addition

it is found that the fractal dimensions and the air entry values increase almost linearly with the dry density. On this basis

a prediction method of SWCC at different compaction degrees is also proposed and tested. The prediction results are in good agreement with the measured values.