Influence of corrugation geometry on sand-structure interface behavior

This paper presents laboratory investigations on the interface between sand and a sinusoidal corrugated surface under a constant normal load using a direct shear apparatus. Using 3D printing technology, a custom direct shear box was fabricated, enabling the construction of various corrugated surface topographies. It was shown that parts produced by FFF (Fused Filament Fabrication) method successfully replicated the properties of traditional metal components in the direct shear box. A series of interface shearing experiments was conducted using different sinusoidal corrugated surfaces. The relationship between the corrugation coefficient, $d/l$ (where d represents wave depth and l represents wavelength), and the shear resistance of the interface was evaluated. Findings revealed that as the corrugation coefficient increased, the forces exerted on the surface and the volumetric changes also increase. Force measurements provided a friction coefficient against the surface, ranging from 0.335 to 0.883. The micro-behavior of the shear zone was analyzed using Digital Image Correlation (DIC), which enabled a qualitative description of failure mechanisms for various surfaces. For surfaces with low-corrugated, direct sliding of the material along the surface was observed, whereas for high-corrugated surfaces, the shear plane appeared above the corrugation valleys, within the material, and at the corrugation peaks. A critical corrugation coefficient, ranging from 0.053 to 0.147, was identified as the threshold between low-corrugated and high-corrugated interfaces. Based on the DIC analysis, the thickness of the shear zone was determined, ranging from 4$\times$$d_{50}$ to 5$\times$$d_{50}$. Finally, this research provides valuable insights into the micro-behavior of the interface between granular material and sinusoidal corrugated surfaces.