Aplicação dos métodos probabilístico e determinístico de estabilidade de taludes de barragem de terra: estudo de caso em Alegrete/RS

Abstract

Slope stability is usually assessed by deterministic methods, in which the soil parameters are regarded as constant and, as a result, there is also a constant safety factor. However, it is known that soil properties have great variability, and this uncertainty directly affects the safety of these structures. As an alternative, probabilistic and statistical methods were developed, which allow the consideration of the associated uncertainties in their formulation and complement the safety factor through the reliability index and probability of failure. In this way, the present work aimed to apply deterministic and probabilistic methods of slope stability in a case study in a small dam in Alegrete/RS. The methodology used consisted of modeling the cross section of the dam under study in the GeoStudio package, where the water percolation inside the soil mass and the stability of the slopes were evaluated by deterministic methods based on limit balance and stress-strain relationships. For the probabilistic analysis, the three main methods used for geotechnical works were used: FOSM Method, Point Estimation Method and Monte Carlo Method. As a result, the stability of the upstream slope is within the recommended ranges for dams, in both deterministic and probabilistic approaches. The downstream slope, however, has a lower rating than recommended. Finally, it is concluded that the use of probabilistic methods complements the analysis of slope stability in a satisfactory way, as long as there are sufficient data regarding the geotechnical parameters treated as variables.