Particle Breakage, Dilatancy and Critical State in Crushable Granular Soils: A Review

Particle breakage is a pervasive micro-scale damage process in granular soils under high pressures, intense shearing, or complex stress paths, and in soils composed of weak or porous particles. By reshaping particle-size distribution (PSD), morphology, and contact networks, breakage alters compressibility, dilatancy, stiffness and strength evolution, and the location (and sometimes uniqueness) of critical and limiting states. Research has shifted from macroscopic inference toward mechanism-based “macro–micro coupling,” enabled by single-particle crushing tests, high-resolution imaging, high-pressure consolidation and large-strain shear/ring-shear testing, DEM fracture modelling, and energy-partition analyses. This review synthesizes representative studies on: breakage quantification and PSD evolution laws; limiting compression curves and micromechanical explanations based on fractal crushing and minimum-particle control; energy dissipation and modified stress–dilatancy relations including breakage work; critical-state non-uniqueness and higher-dimensional state description; and constitutive/numerical modelling strategies from probabilistic crushing to thermodynamically consistent internal variables. Special soils (carbonate sands, volcanic soils, diatomaceous soils) are discussed as benchmarks for transferability. Research priorities are proposed for building a unified, physically based framework that is identifiable from experiments and usable in engineering prediction under monotonic, cyclic, and stress-reversal loading.