Estudo de subpressões em barragens de concreto no contexto da segurança de barragens

Abstract

Structures historically very important to the humanity progress, dams are influenced by several loads, which determine their stability and safety conditions. The uplift pressure, load pressure exerted under a structure, in an upward direction, as a result of the pressure caused by the water percolation through the concrete or rocky massif, is one of the loads that influence the structural design, as well as the resulting stability conditions. The interest in understanding the behavior of the uplift pressures motivated the development of this graduation work, conceived to study the Eletrobras design criteria for determination of the uplift pressure diagrams and to compare the obtained results to the diagrams determined based on instrumentation data. Two instrumented blocks of a dam located in the state of Paraná were selected, being calculated the uplift pressure diagrams based on the design criteria and verified its global safety conditions. Comparatively, it was also determined the uplift pressures from the piezometer records, leading to strengths at least 10% lower than the pressures expected by design criteria, as well as higher safety factors, consecutively. The obtained results lead to the conclusion that the structure is reliable, as seen along its operation, and that the design criteria can be considered conservative.