Abstract: A series of numerical soilstructure shear tests were performed by Particle Flow Code (PFC) in two dimensions, the effect of the roughness of the interface and the particle radius on the thickness of the interface layer were studied. It is shown that the roughness of interface and the particle radius affect the thickness of interface layer significantly; the thickness of interface layer increases with the decrease of the particle radius as well as the increase of the roughness of the interface.

Key words: interface layer, direct shear test, roughness, numerical simulation