A study on the cyclic shear and particle breakage characteristics of the interface between steel and calcareous sand

Research on the mechanical properties of structure-soil interfaces is of great significance to engineering construction in the South China Sea. In this work, an interfacial cyclic shear test between steel and calcareous sand was carried out using self-developed shear equipment, and the macroscopic shear characteristics and particle breakage characteristics were analysed. The results showed that the interfacial peak shear stress under constant stiffness showed more significant weakening characteristics than under constant stress. The calcareous sand showed regular shear shrinkage and dilatancy in a single cycle and was continuously compressed with the number of cycles. The position of the shear stress-normal stress curve moved in the direction of low normal stress with the number of cycles. Under the condition of constant stiffness, the interfacial friction angle at 200kPa increased with the number of cycles, but showed the opposite rule at 1100kPa. The interface shear stiffness under constant stress first decreased and then increased with the number of cycles, while it always decreased under constant stiffness. The relative crushing value increased with the number of cycles; however, the increasing range gradually decreased, and obvious fracture was observed on the surfaces of the broken particles.