Analysis of cracking behaviors of five clayey materials using 3D point cloud data

In recent years, drought-induced soil cracking has become increasingly prevalent, posing significant challenges to geotechnical engineering applications due to the associated hazards. Previous studies have investigated soil cracking behaviors and mechanisms via multi-scale methods. However, research on the spatial distribution characteristics of soil cracks and their depth evolution mechanisms is still rare. This paper analyzes the three-dimensional (3D) deformation of five clayey materials. In this study, 3D surface elevation data of soil samples were acquired using a Gocator 3110 structured-light sensor. The reconstruction process involved point cloud acquisition and rasterization, Delaunay triangulation meshing, and calculation of crack depth. Different cracking behaviors are investigated, such as cracking in opening mode and shearing mode, coalescence and bifurcation of cracks, etc. The mineralogical analysis is carried out to reveal different cracking behaviors of clays. It is concluded that the crack depth of montmorillonite is larger than that of kaolin, reflecting its strong shrinkage characteristic, which makes the crack evolve deeper than the other materials. This technique enables multi-dimensional observation of soil crack propagation. The mineralogical analysis is carried out to reveal the different cracking behaviors of clays. It is concluded that microstructure and mineralogy are key factors influencing cracking behavior. Understanding soil cracking behaviors is significant for engineering protection, geohazard prevention, and geological monitoring.