Effect of Particle Gradation on the Shear Characteristics of Reshaped Rock Material: Experiments and Numerical Simulations

This study takes the artificial rock sample with four different particle sizes as the experimental materials to investigate the effect of particle gradation on the shear strength of artificial plagioclase. The impact of particle grading effect on pore water distribution is analyzed by nuclear magnetic resonance and laser particle size analysis. Additionally, the particle migration, the generation and development of cracks and the stress chain are simulated by PFC (Particle Flow Code). The results shown that: as the particle size increases, the free water volume of the sample increases from 88.70 (A1) to 91.79 (A4), while the bound water volume decreases from 11.29 (A1) to 8.20 (A4). The shear strength increases with the increase of particle size. The maximum contact force between particles increases with the increase of particle size, and the maximum contact force generated at a shear displacement of 2 mm is 1.1653 × 10⁵ N of A4. As the particle size increases, the crack location generated by the sample approaches the shear plane. This paper can provide reference for design and safety assessment of the engineering in the area where distributes the plagioclase.