Critical state elastoplastic constitutive model of angular-shaped and fragile granular materials

Fragile angular-shaped granular materials, such as calcareous sand, rockfill material, and ballast, show complex stress–strain–volumetric relationships due to the effects of particle breakage. This paper presents a proposed constitutive model to simulate the effects of particle breakage on the mechanical response of calcareous sand and rockfill materials in drained triaxial tests previously conducted by other researchers. Experimental results revealed an increase in roundness and a decrease in the critical stress ratio with increased particle breakage in these materials. A breakage parameter is introduced to describe the breakage behaviour of fragile angular-shaped particles. The proposed model includes the effects of the density, stress level, and particle breakage of granular materials. The simulated results show satisfactory agreement with experimental data. Thus, the newly established constitutive model can be used to predict the influence of material density, stress level, and particle breakage in drained triaxial tests of fragile angular-shaped granular materials.