Experimental study of interface performance between calcareous sand and steel pile with different surface roughness and temperatures

Abstract

The shear characteristics of calcareous sand, a typical deposit in the South China Sea, could significantly influence the safety and stability of marine structures. Previous studies showed that many factors, such as temperature and surface roughness, could affect the mobilized shear strength between the calcareous sand and steel surface. Therefore, studies on the shear behaviors of the steel-sand interface under various thermal conditions are necessary. In this study, a new multifunctional sediment shear system has been developed and employed to investigate the shear performance. For this purpose, steel plates with different surface roughness were tested under various normal stress values, shear displacement rates and temperatures. Shear strength and deformation were analyzed using test data to reveal the relationships between several factors and the shear strength of the steel-sand interface. Results from test demonstrate that the interfacial shear strength on rough steel interfaces will be 1.45–3.15 times higher than that on the smooth steel interface. Besides, the shear strength of the interface rises significantly with the roughness of the steel plate. The peak friction angle increases rapidly at the start and then tends to stabilize with the increase of normalized roughness. The interfacial shear strength could be enhanced in low-temperature environments but would reduce in high-temperature environments, e.g. the energy pile, particularly under low normal stress. The shear displacement rate also has a positive effect on the interface shear strength for most cases in this study. Finally, a new nonlinear function is proposed to describe the peak friction angle ratio of foundation interface to consider the effect of temperature and shear displacement rate reasonably.