A hyperbolic model for mechanical behaviour of marginal soil-geosynthetic interface

Locally available marginal soils are of great interest to use as backfill material in geosynthetic reinforced soil structures due to their cost-effectiveness. The advanced stress–strain analysis of these structures necessitates the correct evaluation and the accurate description of marginal soil-geosynthetic interface behaviour. Therefore, the primary objectives of this study are numerical and analytical analysis of the soil-geosynthetic interface behaviour with application of a hyperbolic nonlinear elastic perfectly plastic constitutive model. In this investigation a series of large-scale direct shear tests was performed to evaluate the shear stress-displacement interface behaviour considering two types of marginal soils in contact with five types of geosynthetic materials in different soil moisture conditions. Accordingly, the hyperbolic model was used to simulate the soil-geosynthetic interface behaviour. Moreover, a three-dimensional finite element model of the direct shear test was developed using ABAQUS software and a user-defined subroutine was implemented to consider the hyperbolic interface model. The results indicated a very good agreement between the experimental data and the predicted finite element simulations of the direct shear tests and analytical solutions. Finally, a numerical simulation of a pullout test is presented in this paper with application of the hyperbolic interface model.