Banca de DEFESA: João Paulo Tavares Souza

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : João Paulo Tavares Souza
DATE: 08/02/2023
TIME: 14:00
LOCAL: on line (teams)
TITLE:

ANALYSIS OF THE DECHARACTERIZATION OF TAILINGS DAMS USING THE OLSON METHOD 

KEY WORDS:

Tailings dam, Construction methodology, Olson's Method, Safety Factor.

PAGES: 108
BIG AREA: Engenharias
AREA: Engenharia Civil
SUBÁREA: Geotécnica
SPECIALTY: Obras de Terra e Enrocamento
SUMMARY:

After the accidents at Fundão Dam and Dam 1 of the Córrego do Feijao Mine, Law No. 14,066, of September 30, 2020, decreed the need to decharacterize all upstream tailings dams in operation in the country until February 25, 2022. Since this is an activity that has been poorly studied and with incipient definitions of construction processes, mapping alternative executive methodologies for the decharacterization of tailings dams is of utmost importance. In this context, the aim is to evaluate the susceptibility to liquefaction, using the Olson Method, of a typical section of a tailings dam raised upstream, considering the total removal of material from the structure as the decharacterization methodology. The Olson Method is an empirical technique that uses correlations of SPT and CPT test results to analyze the liquefaction potential of soils. This method is divided into three steps: in the first, it aims to verify the susceptibility of liquefaction of the material, then, it aims to verify the possibility of triggering liquefaction and, finally, the Safety Factor of the liquefied material. Two different construction methodologies were evaluated: removing material from the dam in the downstream to upstream direction and in the opposite direction, from upstream to downstream. The results indicate slightly higher Safety Factors in the analyses considering material removal from downstream to upstream. The higher elevations present lower Factors of Safety in both scenarios, where there is a high relevance of the tailings strength ratio in the overall stability of the structure. As excavation occurs, the strength parameters of the starter dam and raising become predominant, increasing the Factors of Safety in all types of analysis and causing the results of the liquefied analyses to approach the peak scenario values. It can be seen, therefore, that with the progress of the decharacterization, there is no significant influence of the tailings strength properties on the overall stability of the structure, a result in line with what was expected and that corroborates with most of the decharacterization works currently being executed in the country.

BANKING MEMBERS:
Externa à Instituição - TEREZINHA DE JESUS ESPÓSITO BARBOSA - UFMG
Presidente - 404827 - ANDRE PACHECO DE ASSIS
Interno - 1549489 - MANOEL PORFIRIO CORDAO NETO