Dynamic Responses Generated by Moving Vehicles in a Reinforced Embankment Overlying a Void: Insights from a DEM Study

The detrimental effect of moving vehicle loading on the antisettling performance of geosynthetic-reinforced embankments overlying voids has been ignored in current design methods but needs to be carefully investigated at a grain level. Using the discrete element method (DEM), this paper generates a full-scale numerical model of the geogrid-reinforced embankment overlying a cavity and simulates the realistic moving vehicle load by loading adjacent facet elements at prescribed phase differences. The progressively accumulated deflections of the geogrid under periodically moving loads are monitored and validated based on a full-scale test. Detailed microscale perspectives clearly reveal that higher vehicle speeds cause greater degradation of the soil arching but enhance the anchoring performance of the geogrid, which is closely related to the particle vibration behaviors in different regions. For initially complete soil arching, a minor degree of arching degradation is induced with the arching influential zone extending upward in response to the traffic load. For initially incomplete soil arching, a considerable degree of arching degradation is induced with the arching influential height obviously lowered. Once the ratio of the cavity diameter to the embankment height exceeds 1.25, the degradation of the soil arching and anchor effect shows a dramatic increase.