Abstract:

As a typical discontinuous medium, the creep behavior of discrete granular materials strongly influences the formation and evolution of geohazards such as landslides and mudslides. However, systematic studies on the interaction mechanism between particle size and bias stress and its effect on creep behavior are still insufficient. To reveal the coupling mechanism of particle size and bias stress on creep behavior, this study carried out an indoor creep test of silica bead particles under multiple working conditions and systematically analyzed the influence of different particle sizes and bias stresses on the creep characteristics of granular materials. On the basis of the Derec creep model and experimental results, a quantitative calculation model of the creep state of granular materials was constructed, and the influence mechanism of the particle size on the creep parameters of the system was elucidated. The results show that the creep behavior of the granular system essentially reflects the dynamic balance between the internal deformation of the particles and their resistance to deformation. The creep parameter has a significant effect on the creep properties of the system by regulating the interparticle slip and creep behavior. Specifically, as the particle size increases, the creep value of the system increases significantly, and it becomes easier to enter the liquid-like flow state, whereas the deformation resistance of the system weakens and becomes more sensitive to bias stress. The particle size is positively correlated with the initial state parameters and the characteristic strain of the system, whereas it is negatively correlated with the viscous coefficient, the critical creep velocity and the critical creep stress.

Key words: particle size, granular materials, creep, state evolution, Derec model