Effects of particle surface roughness on small-strain dynamic properties of granular materials

The small-strain shear modulus and damping ratio are important dynamic properties of granular soils, which are not only influenced by packing density and stress states of the soil element but also affected by particle characteristics, such as gradation and shape of particles. As one of the important particle characteristics, however, the surface roughness of particles is often ignored by previous investigations regarding the small-strain dynamic properties of granular soils. In this study, the small-strain dynamic properties of specimens of glass beads with different surface roughness were measured using the Energy Injecting Virtual Mass resonant column system. The surface roughness of the glass beads was quantified with the assistance of the three-dimensional interference microscope. The experimental results show that the small-strain shear modulus decreases with increasing surface roughness of particles, while there is no obvious effect of surface roughness on the small-strain damping ratio. Clearly, the effects of surface roughness on the small-strain dynamic properties cannot be ignored particularly when other influencing factors, such as particle shape and gradation, are similar.