Shear behaviors and acoustic emission for calcareous sand-biomimetic plate interface

In offshore engineering construction, calcareous sand is highly prone to particle breakage, which severely affects the long-term stability of structures. To actively regulate interface mechanical responses, snake-scale inspired surface with frictional anisotropy offers great potential. However, the physical mechanism of interaction between calcareous sand and biomimetic surface remains unclear. In this study, interface shear tests and acoustic emission (AE) monitoring were conducted to investigate the interaction between calcareous sand and biomimetic steel plates inspired by snake scale. Test results indicate that the AE signals generated by particle breakage and interface friction of calcareous sand during shearing conform to avalanche dynamics. The average relative magnitude, waiting time distribution, and aftershock sequence distribution are independent of normal stress, roughness, and shearing direction. Furthermore, a quantitative relationship was established between the power-law exponent and both the particle breakage index and the peak friction angle. The results indicate that particle breakage reduces the power-law exponent, whereas friction behavior increases it, highlighting a competitive relationship between these two mechanisms during interface shearing. This study provides a new approach for the nondestructive characterization of calcareous sand particle behavior and the evaluation of sand-structure interface stability.