A study of the micro-configuration of loess based on micro-CT images

The physical and engineering properties of loess have close relationships with the characteristics of its micro-structures. The micro-CT experiments were performed for reconstruction of 3D images to illuminate the 2D pore characteristics and 3D structure characterization of the Malan loess. Firstly, slice images were corrected through the Gaussian filtering and gray images were obtained with the binary method for 2D pore characteristics. Moreover, 3D images were reconstructed in accordance with the analysis of the 3D structure characterization, which was summarized by the 3D chop, aggregate and particle.The research results show that (1) as the results of 2D pore area counting analysis, the pore areas of the soil sample tend to concentrate in the range of 0~2 000 μm². Comparing the total number with the area of pore, it can be concluded that the medium-sized pores play an important role in the soil properties formation. It is also found that the soil pore distribution on the macro level can be regarded as uniform after comparing different layer numbers of void ratio. However, its distribution in different parts of the soil is different from a micro level.(2) Depending on the analysis of the 3D images, it is found that there are four combination relationships among the soil particles in the internal of aggregate: contact, connection, penetration and fusion, and the soil particle morphology can be classified into four shapes: spheroidicity, cone, sheet and bar.