Role of Inherent Anisotropy in the Mechanical Behavior of Sand-Steel Interface Using Simple Shear Testing

To investigate the influence of inherent anisotropy of sand on the mechanical behavior of the sand-steel interface, this study conducted a series of simple shear tests on Fujian sand-steel interfaces with different sand depositional angles. The results were also compared with those of sand-sand interface. The simple shear test results showed that compared to sand-sand interface, the depositional angle of sand had a smaller effect on the peak friction angle φp of the sand-steel interface, but a greater effect on its maximum dilation angle ψmax. In the sand-steel interface, the effect of the sand depositional angle on φp and ψmax was less influenced by vertical stress and relative density, whereas this effect decreased with increasing vertical stress and relative density for sand-sand interface. Under the same test conditions, the shear strength of the sand-steel interface was lower than that of the sand-sand interface, and the trend of the strength ratio with the sand depositional angle was opposite to that of the peak friction angle. Furthermore, the depositional angle of sand also played a key role in the evolution of interfacial shear displacement, with a more pronounced effect at low relative densities but no notable influence from vertical stress.