Interface modeling for mechanistic analysis of geogrid reinforced flexible pavements

Recent research at the University of Illinois has focused on the development of a finite element based mechanistic model to provide design tools and solutions for constructing geogrid reinforced flexible pavements. One essential feature of the mechanistic model is the representation of the soil/aggregate-geogrid interface by the use of a simple, realistic interface element having normal and shear spring stiffnesses between the geogrid and soil/aggregate continuum elements. Varying the shear stiffnesses in the interface elements specified the various levels of interface bonding, i.e., perfect bonding and partial bonding. The mechanistic model pavement response predictions including interface shear stresses compared favorably with the ABAQUS contact model results for a set of model parameters. Further, relative displacements computed at the soil/aggregate-geogrid interfaces were small and unlikely to cause any large movement or slip of the geogrid at the interface indicating the use interface elements with spring stiffnesses was adequate.