Modeling distribution and change of loess pore structure by two-dimensional distinct element method analyses

In loess area, understanding the mechanical properties of loess impacted by micro pore structure is essential for assessing the stability of slopes, mitigating landslide risks and protecting people’ lives and property. In order to investigate the relationship between changes in pore structure and shear behaviors, the discrete element method (DEM) and image processing techniques were employed to analyze the macroscopic features such as sample deformation, bond breakage, and porosity distribution within the numerical samples. Simultaneously, the changes in micro pore structure, including pore size, pore axis ratio, and pore orientation within and outside the shear band zone were investigated. The results present that the shear band formation is relevant to particle displacement, bond breakage, and force chain development, thereby impacting porosity distribution. In addition, the shear band significantly influences changes in macropores and pore orientation distribution, whereas there is a slight connection between the development of the shear band and alterations in micropores, small pores, mesopores and pore axis ratios. A comprehensive insight into the relationship between the occurrence of the shear band and the pore structure development contributes to landslide prevention and mitigation strategies.