The aim of this study was to provide a general conceptual understanding of the effect of hardness and roughness of a continuum surface on its interface shear behavior against granular materials. A carefully designed experimental program was conducted to investigate this issue. The results were utilized to define schematically the general geometric configurations of the constitutive interface shear surface (CISS) in the three-dimensional domain of surface roughness, surface hardness, and interface shear coefficient. The proposed CISS provides a robust mean to understand the coupling effect of continuum surface roughness and hardness on the interface shear behaviour.
- Interface shear