The effect of particle shape on particle breakage and shape evolution in gravelly soils

Abstract

Gravelly soils are widely used in transportation geotechnical engineering, with particle shape and breakage significantly influencing their mechanical behavior. In this study, an abrasion machine was used to generate particles with varying angularity. Subsequently, a series of consolidated drained triaxial tests were conducted to investigate the effects of initial particle shape on both particle breakage and shape evolution. The results indicated that particle breakage increased with higher particle angularity under the same confining pressure. Moreover, materials with higher angularity exhibited a more pronounced decrease in large particles, attributed to distinct particle breakage modes. Particle breakage not only altered the gradation but also led to shape evolution. Angular particles tended to lose angularity due to particle breakage, whereas initially rounded materials exhibited enhanced angularity. As particle breakage progressed, particles with different initial roundness converged toward a similar shape. Based on the experimental data, an empirical formula was proposed to predict the evolution of particle shape during shear processes. This study provides a theoretical foundation for predicting the long-term performance of gravelly soils, with important implications for material selection and stability assessment in transportation geotechnical engineering.