Abstract: The shape of crushed rock particle greatly influences the shear behavior of crushed aggregate. However few quantitative evaluation indices were proposed. PFC2D (Particle flow code, 2D) was utilized in this paper to simulate the biaxial shear condition and the randomly shaped polygon particle generation method was studied based on clump logic. By comparing with the experimental results, the numerical model was validated and the parameters were determined. The angularity index was modified based on current research by dividing the clumped particles into polygons. The effect of particle shape on the shear behavior of open-graded crushed aggregate was analyzed. The results showed that, the AI (Angularity Index) was greatly influenced by the partition density, AI increased and became stable with partition density. The shear strength increased nonlinearly with the axial strain and the morphological characteristics of the curve was obviously affected by particle shape, except ball particle, all the aggregate showed shear hardening. The shear strength and friction angle increased slowly when AI was relatively small before pronouncedly increased with AI, the relationships can be fitted with power function.

Key words: particle shape, shear behaviour, angularity index, discrete element method