Effect of concrete surface roughness on shear strength of frozen soil–concrete interface based on 3D printing technology

For most engineering projects in cold regions, the constraint damage between concrete structures and surrounding soil starts from the stick–slip failure of the frozen soil-concrete interface. The mechanism of the effect of concrete surface roughness on shear strength between concrete and frozen soil was studied to reveal the cause and essence of the stick–slip failure. The concrete surface roughness degrees corresponding to various engineering conditions were quantitatively restored using 3D printing technology. Direct shear tests on the frozen soil–concrete interface were carried out, and mesoscopic structures were analyzed after shearing. The results showed that stick–slip failure types are brittle failure of interface and strain softening failure of frozen soil under the effect of different concrete surface roughness degrees restored via 3D printing technology. The concrete surface roughness exerts a significant effect on the vertical displacement (shear shrinkage or dilatancy) of the stick–slip of a binary body. The correlations among the roughness coefficient, cohesion, and internal friction angle were examined based on the mesoscopic mechanism and Mohr–Coulomb law. The effect of concrete surface roughness on the shear strength of frozen soil–concrete interface was obtained.