Discrete Element Method Investigation of Geogrid-Aggregate Interaction Under Cyclic Wheel Load

Geogrid reinforcement of a base course improves its performance. The interaction of the geogrid with the base is critical to the improved performance but not well understood. The Discrete Element Method (DEM) was used in this study to investigate this interaction under a cyclic wheel load. In the base course, the geogrid reinforcement was placed at the bottom or the mid-depth of the base course. A cyclic wheel load was applied on top of the base course. The effects of the traffic load and the geogrid placement depth on the performance of the geogrid-reinforced base were investigated. Under a heavier load, the geogrid placed at the mid-depth of the base performed better than that placed at the bottom of the base. Geogrid helped widen the distribution of contact force chains and mobilized its tensile strength. Confinement and tensioned membrane effects of the geogrid were two controlling factors for the performance of the geogrid-reinforced base.