Effect of Scale-Dependent Particle Morphology on the Single-Particle Crushing Behavior of Granular Soil

Granular soil particles display complex, multi-scale morphologies, including overall form, roundness, and surface roughness. Due to the interplay among shape features at different scales, isolating the effect of a single-scale shape characteristic on particle crushing behavior is challenging. To this purpose, a noise-based framework was employed to produce particle series with controlled gradients in a single-scale particle shape indicator. Over 600 single-particle crushing simulations were conducted using an improved bonded particle model capable of capturing realistic particle geometries. The simulation results highlight that particle crushing strength is governed by macro-scale sphericity, and the size effect is mainly influenced by meso-scale roundness, while micro-scale surface roughness has a negligible impact on crushing strength. As sphericity increases, both characteristic strength σ₀ and Weibull modulus m increase, indicating improved breakage resistance and reduced variability in crushing strength. The extent of the size effect exhibits a clear negative correlation with roundness, attributed to the contact area between the particle and the loading platens. Regardless of the initial particle shape, crushing strength has a positive correlation with contact area between the particle and loading platens. Finally, a probabilistic model for the characteristic crushing strength, incorporating both particle shape and size, is proposed and demonstrates good agreement with the test data.