Theory for Shear Strength of Granular Materials

Based on statistical methods, a theory has been proposed for the shear strength of a random assembly of spherical cohesionless particles. The theoretical analysis gives a relationship between angle of internal friction φ_cv at constant volume, interparticle friction angle φ_μ, and void ratio e. For comparison, drained triaxial compression tests have been carried out on steel spheres, uniform sands, and glass ballotini of different sizes. When φ_μ is calculated from the experimentally obtained φ_cv values it has been found that φ_μ is independent of void ratio, which is an indirect evidence to support the validity of the proposed theory. Comparison with experimental results on sands suggests that the use of the proposed theory could also be extended to random assemblies of irregular shaped particles as well.