ABSTRACT
Coarse granular materials are increasingly used as fills or base materials for offshore structures, dams, and subgrade for roads. These materials are basically large, angular, and granular rock obtained by blasting the parent rock (Indraratna et al. 1993). The shear strength of granular materials is often represented by Mohr-Coulomb criterion. It is assumed that the shear strength varies linearly with the applied normal stress through two shear strength parameters commonly known as the cohesion intercept and the angle of shearing resistance/friction (Barton 2013). In reality, whenever these materials are tested to high stresses, a non-linear shear strength response is observed (Marsal 1967). The effective cohesion intercept continues to increase while the effective angle of shearing resistance decreases with the increase of effective normal stress. These strength parameters, therefore, cannot be considered as constants in the analysis of granular materials (de Mello 1977)
The factors affecting the shear strength of granular materials include basic friction resistance between particles, relative density, particle fabric, particle size, particle shape, and particle breakage (Bolton et al. 1991). Particle breakage is an important factor when considering the behaviour of granular materials with crushable particles under both low and high confining pressures (Ueng et al. 2000). A more realistic and responsive shear strength criterion, involving only two different strength parameters, that remains practically constant with the applied normal stress, is advocated to represent non-linear response that minimizes the drudgery by conducting a number of triaxial tests on the material (Ramamurthy 2001).
