Abordagem determinística e probabilística na análise de estabilidade de uma barragem de concreto à gravidade

Abstract

Historically, reservation works have been built for thousands of years. In the past, dams were used to accumulate water, for purposes such as supply, irrigation and flood control. Structures like these made the development of society possible. Nowadays, in addition to these, dams have other purposes, such as navigation, tourism, fish farming and for the generation of electricity. It is worth noting that dams are stable structures when there is strict design, execution and maintenance control. The overall safety of these works must be guaranteed through analysis of stability to sliding, tipping, floating, permissible acting stresses, buckling, vibrations, deformations and settlements. Therefore, the main objective of this work is to analyze the stability of a gravity-type concrete dam, from the profile of the spillway section of the Rio Jordão Hydroelectric Power Plant, based on parameters adopted from the characteristic literature, using deterministic methods , and compare the results found in the numerical simulation with the data obtained through the dam stability approach in a probabilistic way using the Monte Carlo Simulation. The calculations were developed through the elaboration of electronic spreadsheets. All requesting and resistant efforts were calculated, in accordance with the Criteria Manual for Civil Projects of Hydroelectric Power Plants prepared by Eletrobrás in 2003, and the checks regarding tipping, slipping and floating compose the result called as deterministic. Subsequently, the variability information of the parameters considered for the dam is inserted through the arbitration of a standard deviation. Concomitantly, a pseudo-random number simulator was created so that the entire calculation process has a real-event simulation character, presenting as a result the rupture probability and a reliability index. It is concluded that probabilistic approaches help to obtain a more significant result, since the uncertainty of the parameters involved is considered, presenting results linked to a level of confidence. And that, based on the parameters considered for the simulations, the dam presented safety factors higher than the minimum recommended by the criteria of Eletrobrás (2003).