Characteristics of particle breakage and constitutive model of coarse granular material incorporating gradation evolution

Abstract

Single particle crushing tests were carried out to research the breakage characteristics of natural rockfill particle. The results showed that the size distribution of broken particles can be described by the normal distribution, and the size distributions of all size fractions converge to a uniform normal distribution after being normalised by the size of the parent particle. Based on the breakage characteristics of rockfill particles, a gradation evolution model was proposed to predict the evolution of the gradation curve of triaxial specimen. This model adopts the loading manner of incremental stress. The correlation among the relative breakage indexes was analysed in terms of the ratio of areas enclosed by the gradation curves and it was found that there is a linear relationship between different indexes. This indicates that there is no essential difference among these indexes from the mathematical point of view. Finally, an elastoplastic constitutive model incorporating the gradation evolution model was developed. This model can predict the stress–strain behaviour and gradation evolution of triaxial specimens of limestone rockfill under the conditions of consolidation, drained and quasi-static shear loading.