Microstructure and fractal characteristics of red clay particles in existing foundation based on SEM images

The IPP (Image-Pro Plus) software was used to extract and process the information of SEM images of three kinds of existing red clay in a factory, Guizhou Province, which helps to make qualitative description and quantitative analysis to the microstructure of the soil from the study site. In addition, the fractal theory is applied to analyze the SEM images, and the method of calculating the three-dimensional fractal dimension of particles in the IPP software is proposed. The results show that，(1) The parameters of shear strength increase with the growing number of microparticles and the ratio of particle morphology, and decrease with the average area of particles. (2) The distribution and morphology of particles have obvious fractal characteristics, with fractal dimensions between 2 and 3. The parameters of shear strength increase with the increase of particle distribution and fractal dimension of particle morphology. (3) It is feasible to use the IPP software to calculate the three-dimensional fractal dimension of soil particles. Compared with the method of building three-dimensional models, this method is simple and easy to use, and its analysis results are reliable.