A rockfill particle breakage evolution model for predicting gradation changes

Abstract

Particle crushing will affect the strength and deformation characteristics of rockfill materials. At present, the particle crushing and corresponding gradation change laws of rockfill materials under different mechanical states are not clear. In this paper, the fractal gradation equation is combined with the existing particle crushing results of rockfill under triaxial shearing, and a more convenient equation system model is constructed, which can realize the transformation of "stressstrain-breaking index-gradation distribution". The fractal gradation equation was used to fit the gradation of four different rockfill materials, and it was found that the fitting effect was good. Combined with the particle breakage index and the fractal gradation equation proposed by Einav, the fractal dimension D can be derived from the particle breakage rate BE through equation transformation, that is, the breakage index is converted into a gradation distribution. Based on the existing particle crushing test data, a model that can predict the crushing index under different mechanical conditions is proposed. The model reflects the evolution relationship of the crushing index with the shear strain and average normal stress. Fitting was performed to verify the accuracy of the model, and the conversion between stress-strain and crushing indexes was realized. Combining the two transformation models, the evolution model of the gradation distribution law under different mechanical conditions can be obtained.