There are a great number of soil-structure interaction problems during construction

and the mechanical characteristics of the interfaces may have significant effects on the forced deformation and interactions of soil-structure systems. Hence

following the slip theory of plasticity

the macro deformation of soil-structure interfaces was decomposed into a macro normal deformation and a series of orientated micro shear deformations associated with virtual micro shear structures in the shear plane. Based on the principle of virtual work

a multi-shear bounding surface model for coarse granular soil-structure interfaces was established in consideration of the states of coarse granular soil and within the framework of bounding surface elasto-plastic theory. Each micro shear response contains a stress-strain relation and a stress-dilatancy relation at a micro level. By introducing a state parameter dependent on soil density and normal stress

the model was used for characterizing the deformation and strength characteristics of soil-structure interfaces in different states. The effectiveness of the model was confirmed by simulating the available published interface tests between coarse granular soil and structure interfaces subjected to monotonic and cyclic loadings for two- and three-dimensional stress paths.