Examination of interface roughness and particle morphology on granular soil–structure shearing behavior using DEM and 3D printing

•3D printing particles and interfaces were used to investigate the coupling effects of soil-particle shape and surface roughness on SSI.•The increase of asperity inclination resulted in significant particle “delamination” and lateral “slip” at the interface.•Particle backward and forward falling movement in the vertical shear plane were observed and used to define the shear zone thickness.•Threshold of particle shapes and interface roughness on particle displacement and shear strength were identified.