Experimental and simulation study on size effect of crushing strength of rockfill particles

Particle breakage significantly influences the mechanical properties of rockfill materials. Given that particle strength diminishes with increasing particle size, coarse-grained materials are particularly vulnerable to performance degradation. Understanding the size dependency of particle strength is essential for advancing research on the scaling effect of rockfill materials. In this paper, the single particle crushing test was firstly conducted on limestone, involving particle sizes ranging from 20 to 120 mm. The results indicated that the crushing strength followed a Weibull distribution, the characteristic strength exhibited a power-law relationship to particle size, and the power index was -0.54. Then a polyhedral block model was developed using Voronoi partitioning, and the parallel bond contact model was employed to simulate the crushing test. The tensile strength and cohesion of the bond were set to be size-dependent based on experimental findings. The simulation results confirmed that the particle strength distribution aligned with the experimental data, effectively capturing the size dependency of particle strength. Finally, the influence of element size on the statistical characteristics of particle strength was analyzed. It was determined that the ratio of element size to particle model size should be at least 4, with the model containing approximately 50 rigid blocks. This study can provide valuable insights for conducting numerical experiments on crushable granular materials.