Segurança nas barragens Gangorra e Itaúna contra erosão interna

Abstract

Embankment are structures susceptible to seepage that can cause internal erosion processes, a phenomenon in which the fine particles of the soil are carried by the flow into the structure, which can lead to soil loss. The study of the processes in the dams located in the semi-arid state of Ceará is important, due to the greater vulnerability of the structures in prolonged periods of drought and reservoir filling scenarios, contributing to soil wear.A structure responsible for retain as soil particles and paralyzing internal erosion processes are the granular filters, which makes it necessary to good design of the granulometry of the filter materials. The selection criteria usually used, such as the Terzaghi criterion, adopted in dams projects analyzed, are not suitable for all types of filters, since they are restricted to low graded soils. Recent methods that incorporate drainage void sizing result in a more realistic approach. The present work analyzes the criterion for the size of the voids of Indraatna and Raut (2008), together with the Terzaghi criterion, where they perform simulations on the two criteria, and apply two dams located in the state of Ceará, Gangorra and Itaúna. The results show that the theory of voids in the association with the state of compression to describe the behavior of the filters are more efficient in the conventional Terzaghi criteria, pointing out a vulnerability for one of the cases analyzed.