Examples of polyhedra used in the simulations

By means of contact dynamics simulations, we investigate a dense packing composed of irregular polyhedral particles under quasistatic shearing. The effect of particle shape is ana- lyzed by comparing the polyhedra packing with a packing of similar particle size distribu- tion but with spherical particles. The polyhedra packing shows higher shear stress and dilatancy but similar stress–dilatancy relation compared to the sphere packing. A harmonic approximation of granular fabric is presented in terms of branch vectors (connecting par- ticle centers) and contact force components along and perpendicular to the branch vectors. It is found that the origin of enhanced shear strength of the polyhedra packing lies in its higher force anisotropy with respect to the sphere packing which has a higher fabric anisotropy. Various contact types (face–vertex, face–face, etc.) contribute differently to force transmission and fabric anisotropy. In particular, most face–face contacts belong to strong force chains along the major principal stress direction whereas vertex–face contacts are correlated with weak forces and oriented on average along the minor principal stress direction in steady shearing.