The problem of soil-structure interface is an important part in studying of soil structure interaction. The interface between soil and structure is widely present in water conservancy, civil engineering, municipal and transportation projects. Roughness is the main factor affecting the mechanical properties of the contact surface. From this requirement, a new contact model has been developed that takes into account the relative surface roughness. It is based on the granular hypoplasticity. The experimental results are compared with simulations using the Mohr-Coulomb model and the new model, respectively. It is shown that the new models can represent the non-linearity of the mechanical properties of the contact surface and agree well with the experimental data.

The fabric anisotropy and anisotropic parameters have great effect on the mechanical property of sand. Based on the existing anisotropic model, a modified anisotropic hypoplastic model is developed by incorporating the relation between fabric tensor and anisotropic parameters into the nonlinear part of the constitutive model. The applicability of the improved anisotropic hypoplastic model is validated by comparing with the existing model and experimental data. As a result, it is found that the modified model can well predict the mechanical response of anisotropic sand.