Modelagem geotécnica de uma barragem de terra

Abstract

Earth dams are important structures from the Brazilian socioeconomic point of view, as they are an element that makes up the infrastructure of several productive sectors. Thus, the development of the geotechnical area contributes to the safety of dams from the application of new tools, which allow the simulation and verification of different scenarios to which these structures can be subjected, serving as an aid for decision-making in the field. Thus, the objective of this work was to model a study section of the Três Irmãos Dam, with the aid of the GeoStudio package tools. In this process, a bibliographical survey of the properties of the geotechnical materials was carried out and the percolation, stability, stresses and deformations analyzed for the scenarios of first filling, permanent flow regime and rapid drawdown. The study of percolation as well as stresses and deformations was carried out using the Finite Element Method, while the stability analysis was carried out using the Limit Equilibrium approach in which the Morgenstern-Price method was adopted. To complement the stability analysis, for the most critical deterministic scenario, a probabilistic simulation was performed using the Monte Carlo Method. As a result, for percolation, a value of 350 days was found for the dam to reach the permanent flow condition and 36 minutes for the critical drawdown. As for stability, the most critical region found was the upstream balance berm, which presented the lowest Factor of Safety among all the deterministic analyses. Thus, a probabilistic approach was applied to this critical condition, which had a probabilistic minimum safety factor below the deterministic one and a failure surface different from that previously found. However, observing the result of the FS probability distribution, it was concluded that the number of simulations of 50,000 was not enough for there to be convergence in the results of reliability index and failure probability. Finally, using the elastic linear model for the materials that make up the dam body and its foundation, significant settlements were observed at the studied points during transient regimes with rapid consolidation in stationary regimes.