Estudo de caso: análise de estabilidade de taludes com metodologia numérica e equilíbrio limite em uma ponte de Macapá-AP

Abstract

The interaction between human beings and space – whether natural or anthropomorphized –requires compliance with certain parameters that can provide guarantees about safety in terms of its use and occupation by man. When it comes to slopes – earthworks characterized by the presence of an inclined surface –; its stability can be analyzed through probabilistic and deterministic approaches, the last presented here through the limit equilibrium method and the finite element method (FEM) – turning to the determination of a factor of safety (FS) that relates resistant forces and mobilizing forces in an attempt to avoid the establishment of a scenario that promotes landslide. In this sense, it was identified in the city of Macapá (AP) the existence of a densely occupied area that contains the main instrument of infrastructure in urban mobility destined to connect different areas of the same, the Sérgio Arruda bridge (PSA) – which interposes a body of water, the Canal do Jandiá, delimited by a slope. In view of the fact that the structure no longer serves the purposes for which it was designed, its replacement is foreseen, thus observing the change in the loading conditions that will affect the slope located in its surrounding. Therefore, the objective was to establish a comparison of the performance of conventional analysis methods of limit equilibrium against the FEM applied to the real scenario of the slope that delimits the Canal do Jandiá. For this purpose, the Geo5 software was used as a computational analysis tool, incorporating information about the geometry of the slope section – obtained through a topographic survey –; characterization of the soil in the region – based on geotechnical studies and their insufficiency based on theoretical information –; and finally, estimation of loads from the current structure, as well as the addition of these from its replacement by a new structure; adding to the study the simulation of theoretical scenarios for a predominantly sandy soil and subsequently a predominantly clayey soil. After analyzing the models produced, the FS was obtained with a satisfactory approximation for the proposed methods, observing its decrease and the increase in variance as the external overloads increased; with regard to the geotechnical composition of the adopted interfaces, for the cases studied, the sandy soil presents the highest FS indices, on the other hand, the clayey soil presents, in all cases, the lowest FS indices. For the original scenario, under the conditions of application of overloads, a relief of tensions was observed through the application of overloads originating from the future PSA, however, without retroacting from an unstable situation – considering the overloads from the current PSA –; for a stable situation, which corroborates the need to evaluate the implementation of an auxiliary containment structure in view of the intense occupation of the region and high associated risks.