The influence of surface roughness on the shear mechanical behavior of 2 mm spherical particle materials

Using glass beads as an ideal material analogous to soil particles makes it feasible to explore the effects of particle interactions on the mechanical behavior of the material. In this study, 2 mm high-precision spherical glass beads were selected as the raw material, and three test samples with varying surface roughness were produced using sandblasting technology. After quantifying the surface roughness of the particles, samples were prepared, and a series of laboratory triaxial consolidation drainage tests were conducted to investigate the shear behavior of particle materials with varying roughness levels. This investigation explores the effects of variations in particle surface roughness on the stress-strain characteristics, shear strength, critical state, and stick-slip behavior of triaxial samples. The experimental results indicate that an increase in particle surface roughness significantly raises the peak deviatoric stress, and the stress-strain curves predominantly exhibit strain softening behavior. Additionally, the slope of the critical state line increases, and the stick-slip behavior becomes less pronounced. The variation trend of the roughness index is similar to peak friction angle (phi max), peak deviatoric stress growth rate, slope (k) of the critical state line, and the maximum deviatoric stress drop (Delta qmax) during stick-slip process.