Proceedings of the 7 th World Congress on Civil, Structural, and Environmental Engineering (CSEE'22) Lisbon, Portugal Virtual Conference – April 10 – 12, 2022 Paper No. ICGRE 218 DOI: 10.11159/icgre22.218 ICGRE 218-1 Numerical Analysis of Unpaved Roads Subjected to Surface Maintenance Bárbara Gonçalves Mourão, Ennio Marques Palmeira, Juan Félix Rodriguez Rebolledo University of Brasilia Darcy Ribeiro University Campus, Brasilia, Brazil barbara.mourao.bgm@gmail.com; palmeira@unb.br; jrodriguezr72@unb.br Abstract - Geosynthetics have proven to be beneficial in reinforcing soils, especially in problems with large deformations, such as unpaved roads built on soft soils and subjected to high loads. Due to heavy machinery traffic, this situation occurs even during the construction period of the road, in which is necessary to perform surface maintenance to the execution of the fill layers. Several experimental studies have indicated an improvement in the mechanical performance of unpaved roads when subjected to surface maintenance. The present research aimed at numerically investigate the behavior of unreinforced and reinforced unpaved roads subjected to surface maintenance. The analyses consisted of the following steps: determination of geostatic stresses in the subgrade; inclusion of the fill layer, as well as the geosynthetic reinforcement at the interface between the materials; application of a distributed load on the fill; unloading; execution of the surface maintenance from the deformed configuration of the fill; and reapplication of the load. The results indicate that the mechanical behavior of these roads will be better represented by the sequence described. Furthermore, relevant information on loads in the reinforcement and influence of material properties were obtained. Keywords: Geosynthetics, Unpaved Road, Large Deformations, Surface Maintenance, Numerical Analysis. 1. Introduction Unpaved roads are predominant in Brazil's road modal and play an important socioeconomic role for rural dwellers, as well as for the forestry, mining, and agriculture industries. These roads, especially when made of weak subgrades and subjected to high loads, constitute a problem of large deformations, motivating the use of reinforcement alternatives such as geosynthetics. Among their benefits are an increase in the service life of the road, a reduction in construction costs by decreasing the thickness of the embankment layer, and an increase in the time required for periodic maintenance interventions [4]. The types of geosynthetics most used as reinforcement in unpaved roads are geotextiles and geogrids. Reinforcements, particularly geogrids, improve road performance mainly by enhancing the lateral confinement mechanism, guaranteed by the interlock between geosynthetic and aggregates, and by the membrane effect, mobilized from the wavy shape of the geosynthetic when subjected to large deformations [8]. In the case of geotextiles, these can also contribute as a separation element, minimizing the contamination of the fill material by subgrade fines. Due to heavy machinery traffic, this scenario of large deformations occurs even in the road construction period, requiring continuous filling of wheel tracks during the execution of the fill layers [11]. Several authors have experimentally shown the benefits of surface maintenance on the mechanical performance of roads, particularly in reinforced cases, due to the additional traction provided in the geosynthetic [1, 5, 6, 7]. Several numerical works have evaluated the performance of geosynthetics as reinforcing elements using the Lagrangian formulation of the Finite Element Method, proposed by [2], to successfully model large deformation mechanisms [3, 9, 10]. This formulation involves updating the nodal coordinates of the elements during the analysis, although it is not restricted to this [12]. On the other hand, there are not known results of numerical analyses that consider the surface maintenance required since the road execution phase. The objective of this research is to numerically evaluate, with and without the presence of geosynthetic reinforcement, the performance of unpaved roads built on soft soils after surface maintenance due to excessive deformation. To this end, the tests performed by [5] were simulated.