Programa de Pós-Graduação em Engenharia de Barragem e Gestão Ambiental - PEBGA/NDAE/Tucuruí

URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/9395

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Análise dos efeitos da detonação na estabilidade de talude em mina de ferro no Quadrilátero Ferrífero em Minas Gerais
(Universidade Federal do Pará, 2022-08-03) AZEVEDO, Daniel Prado; MARQUES, Eduardo Antonio Gomes; http://lattes.cnpq.br/6725413897416818; ALENCAR JÚNIOR, Júlio Augusto de; http://lattes.cnpq.br/3663658632717465
The vibrations induced by blasting in mining are finite waves that can disrupt geotechnical structures. For the present research, seismographs were installed in various positions along a slope with approximately two hundred meters of difference in height from the bottom of the pit to the top, in order to analyze the speed and acceleration of the particles at the moment of the wave transmission and their consequences to the stability of rocky mass. It is known that the course of these vibratory oscillations causes the particles to move and then return to the equilibrium state. Therefore, it is important to study which waves were generated in the detonation and their behavior in the lithology covered. A slope in the selected mine, Vale S.A. property, was analyzed, which is composed mostly of phyllite and quartzite, sometimes continuous, sometimes discontinuous, as there is a fractured zone of N / S orientation that extends from the top of the slope to its base. In this context, there are at least 3 fracture directions that act as an escape zone for groundwater, constituting a geotechnical problem of material disaggregation, resulting in great erosion. The vibrations induced by the detonations of explosives in the mine can increase the erosion condition when they propagate through the fractured area. The highest seismographic reading obtained among the seismographs was used in this study and the evaluation of the reduction in the safety factor of selected sections was carried out. Later, the maximum value for vibration in which the slope remains stable is also calculated, on Slide2 software. The evaluation of the results on the slope Allowed the interpretation of the effects of vibrations on the slopes reduced between 4.1% and 4.8% the values of the safety factors and shows that the lower the slope safety factor, the greater this interference from the vibration in the stability of the structure. A difference equal to 8% was observed when comparing the section with the highest Safety Factor and the one with the lowest Safety Factor.
Acesso aberto (Open Access)
Estudo da erodibilidade de solos do reservatório da UHE Tucuruí
(Universidade Federal do Pará, 2019-10-30) SILVA, Lucas Manoel da; GOUVEIA, Fernanda Pereira; http://lattes.cnpq.br/1772072130947378; ALENCAR JÚNIOR, Júlio Augusto de; http://lattes.cnpq.br/3663658632717465
The Tucuruí Hydroelectric Power Plant, besides being the 5th largest hydroelectric plant in the world in generating capacity, transfers electric power to several Brazilian states and, having a reservoir of 2,917 km², is strongly subject to erosion. Several studies report the occurrence of erosive features near the its reservoir, besides being constantly subjected to laminar erosive actions in its drainage areas. In this work we carried out bibliographical surveys, field checks and direct and indirect analyzes of the erodibility of samples of the main soils of the Tucuruí HPP reservoir. Indirect analyzes employed semiempirical formulations based on physical and geotechnical characteristics of the, and the direct ones tested undisturbed samples under runoff, exposure to gradual and total water immersion processes, and under intense sample remoulding levels for evaluations in the Tropical Compacted Miniature - M.C.T. It was possible to notice a significant increase in the reservoir territorial occupation, favoring the exposure to erosive processes, and that the samples classified as Pedisol as Ultisol and Yellow Latosol presented average erodibility rates, as 0.0392 and 0.0323 g / cm² / min / Pa and low levels of disaggregation, while Red Latosol presented low erodibility as 0.002 g / cm² / min / Pa, medium to high levels of disaggregation and expansions, in the MCT methodology. These conclusions indicate that the agricutural activity in the area must grow crops that maintain the surface coverage of the first soil areas, and the prevention of uses that may disrupt and damage the last soil.
Acesso aberto (Open Access)
Estudo de caso de execução de aterros com misturas de argila e rejeito de bauxita
(Universidade Federal do Pará, 2023-06-05) EÇA JUNIOR, José Roberto Guimarães; ALENCAR JÚNIOR, Júlio Augusto de; http://lattes.cnpq.br/3663658632717465
The reuse of mining tailings is a real demand due to the search for sustainable exploitation of resources. Brazil is the holder of one of the largest mineral assets and, as such, is one of the largest producers and exporters of minerals on the planet. The search to meet the demand for the production and extraction of minerals has been growing every day and, along with this growth, the search for the reduction of environmental impact without loss of profitability has also been increasing. Currently, research with these objectives is extremely necessary in the search for solutions to these problems. Several studies seek alternatives for the reuse of the waste on a large scale, and one of the alternatives that make this application feasible are landfills within the enterprise itself. With the continuous updating of the regulations that govern dams, it is often necessary to reinforce old structures in order to increase the safety factor. This paper sought to analyze the applicability of mixing clay with bauxite tailings, in different proportions, for feasibility of its use in controlled landfills. In addition, it aimed to make feasible analyses regarding the research that evidenced the reuse of ore tailings and additions of other tailings materials. A case study was carried out in a mining company, collecting clay and tailings samples, and after being characterized, a pilot and an auxiliary mix were defined. As results, the mixture of 50% bauxite tailings with 50% clay resulted in a material that achieved California Support Index (CSI) values higher than those required by the Dnit 108 of 2009 standards, besides considerably improving the geomechanical characteristics when compared to the pure tailings. Thus, this research contributed to evaluate the applicability of compositions of clay and bauxite tailings in an experimental embankment in a mining area.

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