Effect of the intermediate principal stress on the mechanical behaviour of breakable granular materials using realistic particle models

The effect of the intermediate principal stress (relative magnitude quantified by b ) on the mechanical behaviour of breakable granular materials was studied using a DEM simulation of realistic particle models. The realistic particle model obtained by 3D scanning was divided into coplanar and glued Voronoi polyhedrons to reflect particle morphology more truly and fracture. After isotropic compression, a series of true triaxial tests under various b values were conducted using cubic and isotropic specimens. The macro-behaviour showed that the peak and critical shear strength first increased to a crest and then decreased with increasing b . Particle breakage caused a decrease in dilatancy and an increase in coaxiality. Increasing b resulted in an increase in cracks oriented in the intermediate principal stress direction and more broken particles. From the particle-scale analysis, as the b value increased, both the coordination number at the peak state and the percentage of sliding contacts at the critical state decreased. Particle breakage reduced the normal and shear contact forces at the critical state.