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

The small-strain shear modulus and damping ratio are the important dynamic properties of granular soils, which are influenced by the packing density and stress states of the soil element as well as the particle characteristics including gradation, shape of particles, etc. As one of the important particle characteristics, however, the surface roughness of particles is often ignored by the 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 roughnesses are measured using the energy injecting virtual mass resonant column system. The surface roughness of the glass beads is quantified with the assistance of the three-dimensional interference microscope. The experimental results show that the small-strain shear modulus decreases with the increasing surface roughness of particles, while there is no obvious effects 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.