Analysis on evolution of complex network structure of soil granular materials

Complex network analysis methods can be applied to analyze the structural evolution of granular materials during loading and establish the relationships of mechanical parameters of these materials between micro/meso and macro scales. This articles mainly reviews our research results in recent years on the structural evolution of granular materials and the relationship between microscopic parameters and macroscopic mechanical properties using complex network methods. Firstly, the basic concepts of complex networks (average degree, clustering coefficient, average path length, and force chain) are introduced. Then, the microstructural evolution of granular materials under biaxial conditions and the network contact parameter changes during the initiation and sliding of soil slopes are analyzed. Furthermore, the microstructure evolution of granular materials considering particle shape, intermediate principal stress coefficient, and complex loading paths is discussed. Finally, the mesoscopic structural parameters of the contact network are associated with the macroscopic mechanical properties, and relationships between the state parameters and average degree, the microscopic structural parameters and soil dynamic strength, the average degree as well as shortest path length and yield function of the modified Cam clay model, and the average degree and the ground vertical pressure are established. The parameters in the unified hardening model are modified based on the maximum flow model.