The Material Deformation and Internal Structure Development of Granular Materials under Different Cyclic Loadings

Abstract

Common structures in engineering such as slopes, roadbeds, ballasts, etc., are closely related to granular materials. They are usually subjected to long-term cyclic loads. This study mainly focused on the mechanical behaviors of randomly arranged granular materials before they reach a stable state under different cyclic loads. The variation of the maximum axial strain and the influence of CSR (cyclic stress ratio) were analyzed. The energy consumed in each cycle under constant confining stress loading condition is significantly greater than that of the fixed wall loading condition. The internal deformation evolution of granular materials is studied in detail. The deformation mode of granular material under cyclic loading at different positions inside the material is different according to the strain variation. In addition, the strain, force chain structure and contact force magnitude are combined to explore their effects on local deformation of granular materials under cyclic loading. From the perspective of the deformation form, the material sample can be divided into several regions, and the ability to adjust particle positions determines the deformation mode of different regions. The changes of local strain with the cyclic loading also reflect the contribution of particle displacements to the evolution of microstructure. This research will provide insights into the understanding of granular materials behaviors under cyclic loading.