Testing and modeling of soil-structure interface

An accurate modeling of soil-structure interfaces is very important in order to obtain realistic solutions of many soil-structure interaction problems. To study the mechanical characteristics of soil-structure interface, a series of direct shear tests were performed. A charged-coupled-device camera was used to observe the sand particle movements near the interface. It is shown that two different failure modes exist during interface shearing. Elastic perfect-plastic failure mode occurs along the smooth interface, while strain localization occurs in a rough interface accompanied with strong strain-softening and bulk dilatancy. To describe the behavior of the rough interface, this paper proposes a damage constitutive model with ten parameters. The parameters are identified using data from laboratory interface shear tests. The proposed model is capable of capturing most of the important characteristics of interface behavior, such as hardening, softening, and dilative response. The interface behaviors under direct and simple shear tests have been well predicted by the model. Furthermore, the present model has been implemented in a finite element procedure correctly and calculation results are satisfactory.