A Hierarchical Single-Surface Model for an Unsaturated Soil-Structure Interface

In this paper, according to the shear test of the interface between unsaturated soil and steel plate, the modified apparent roughness is used to describe interface roughness. And considering the influence of matrix suction and interface roughness, the stress variable is constructed to improve the yield and plastic potential functions. Then a modified hierarchical single-surface elastoplastic interface constitutive model (HISS-Unsaturated-Int model) is set up. The finite element calculation of HISS-Unsaturated-Int model is achieved by compiling and calling the user subroutine FRIC of ABAQUS. The interface shear test between unsaturated soil and structure with different water contents and the pull-out shear test between unsaturated soil and soil nail are simulated. The calculation results are consistent with those of experiments, which shows the modified interface constitutive model can effectively predict the shear mechanical properties of soil-structure interface under different soil moisture content, normal stress and interface roughness.