Three-dimensional mesoscale modelling of the compressive behaviors of coral sand

This paper develops a novel three-dimensional (3D) mesoscale modelling approach to study the mechanical responses of coral sands under quasi-static and dynamic compressive loading. A series of algorithms were developed to generate the 3D random particle models with controllable shape and size configurations to simulate the coral sands with random shape characteristics. Subsequently, a new compaction algorithm combining the gravity action and mechanical motion of particle models was proposed to create the 3D sand particulate system with various particle gradations. Using the 3D unstructured meshing algorithm, the finite element model of particulate system was obtained. Finally, the quasi-static and dynamic compressive behaviors of coral sands were numerically investigated in terms of the axial/lateral stress-strain curves, the mesoscopic deformation processes, and the particle breakage patterns. The results indicate that there are obvious differences in the stress-strain curves and deformation modes of coral sands under quasi-static and dynamic compression loads. Through the explicit simulation and quantitative analysis on the deformation process and particle breakage of coral sands, the grain-level responses and failure mechanisms of coral sands under different loading conditions were fully understood. Above all, it was demonstrated that the developed 3D mesoscale model has a significant feasibility in simulating and analyzing the mechanical properties of sand particulate system.