State-of-the-art review of research on the particle shape of soil

Particle shape is one of the most important characteristics of particles and its correlation with mechanical properties has attracted great attentions. In order to systematize the influence of particle shape on the mechanical properties of aggregates, the research results of physical characterization, numerical simulation and laboratory test of particle shape were summarized and analyzed. The results show that the definition method of particle shape based on three scales (form, angularity and surface texture parameters) is the most ideal method to describe the particle shape characteristics. The numerical method can simulate the shape of a single convex particle and the arrangement structure of a convex particle assembly, but the characterization of concave particles by numerical methods is not accurate enough. There are correlations of particle shape with pore structure, natural angle of repose, limited void ratio and particle size. The permeability coefficient of the aggregate is largely controlled by the shape characteristics of the particles under the same gradation and porosity. Due to the difference in interparticle locking and the number of contact points, the particle shape in uniform particle size affects the small strain strength, peak strength, residual strength of the aggregate and the dilatancy. Finally, the problems in particle shape research are discussed and future research directions are proposed.