Geogrid-aggregate interlock mechanism investigated through aggregate imaging-based discrete element modeling approach

Geogrids are commonly used in road construction for stabilization and reinforcement purposes. Factors affecting the interaction or interlock mechanisms between geogrids and aggregates may include, but are not limited to, aggregate size and shape and geogrid types and properties. To better quantify these effects, an aggregate image aided discrete element method (DEM) modeling approach is introduced in this paper. DEM simulations of laboratory direct shear tests carried out on both unreinforced and geogrid-reinforced aggregate shear box samples indicate that the aggregate imaging aided DEM can accurately predict both unreinforced and geogrid-reinforced aggregate strength properties. The use of geogrids increased the shear strength of the aggregate assembly by constraining the movement of the aggregates in the shear zone, which is often referred to as the geogrid's stiffening effect in this aggregate-geogrid composite system. Preliminary findings on the effects of geogrids with various opening shapes and geometries on the mechanical interlock are also presented to demonstrate the effectiveness of the aggregate image aided DEM model and its potential for quantifying the individual effects of geogrid aperture size and shape relative to aggregate size and shape, gradation, and density, as well as the shape and stiffness of the ribs and the stiffness of the junction between the ribs of various geogrid products.