A novel soil breakage index incorporating particle surface energy change and its application to predict the evolution of PSD during triaxial shearing

Particle breakage is an unavoidable phenomenon in granular soils, fundamentally representing the transformation of deformation energy into the surface energy. This paper, based on fractal theory, derives analytical solution for the breakage index incorporating particle surface energy change. It compares this novel breakage index with the established breakage indices. Qualitatively, the novel breakage index demonstrates similar trends to the established breakage indices. Quantitatively, the established breakage indices tend to overestimate the degree of particle breakage. Utilizing the novel breakage index, a particle breakage model and a particle size distribution (PSD) evolution model were suggested and validated. The surface morphology of the particle breakage model is found to conform to a hyperbolic paraboloid. The PSD evolution model accurately reflects the evolution trends of granular soils. Notably, quartz sand exhibits relatively high prediction accuracy, while the prediction accuracy for rockfill and carbonate sand is slightly limited.