Finite Element Analysis of Geogrid-Stabilized Unpaved Roads

The need to increase the durability of unpaved roads and the need to improve driver comfort have led to this research: to focus more attention on the use of reinforcements for this type of road. Unpaved roads are created by using an unbound granular base layer placed on compacted cohesive soils. When the subgrade is weak, due to its poor consistency and high compressibility, generally, a geosynthetic reinforcement (geogrid and/or geotextile) is placed over the subgrade, followed by a compacted granular fill layer. The use of geosynthetics can produce several benefits, such as draining, reinforcement, filtering, separation, and proofing. This paper aims to present a numerical investigation using 3-D Finite Element Modeling (FEM) to analyze the improvement, in terms of the rutting reduction of an unpaved road system, reinforced by a geogrid, under repeated traffic loads. 3-D FEM analysis was carried out on two unpaved road sections, one reinforced and the other unreinforced, with both subjected to an impulsive wheel loading. It can be concluded that a significant improvement in pavement behavior is obtained by placing a geogrid layer at the base–subgrade interface. In fact, the obtained results show that geogrid reinforcement can provide a relevant contribution to the reduction of permanent deformations.