Banca de DEFESA: INGRID GUIMARÃES SILVEIRA E SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : INGRID GUIMARÃES SILVEIRA E SILVA
DATE: 31/10/2022
TIME: 14:00
LOCAL: https://conferenciaweb.rnp.br/webconf/denise-de-carvalho-urashima
TITLE:

Hydro-Geotechnical Modelling of a Tailings Dam raised centerline

KEY WORDS:

tailings dam; seepage; stability; safety factor; numerical modeling.

PAGES: 140
BIG AREA: Engenharias
AREA: Engenharia de Minas
SUMMARY:

In the ore beneficiation process tailings that can be discarded in the form of pulp or mud, in structures such as dams or dykes are generated. In the event of a break, those tailings can cause high environmental, social and economic damage. Moreover, the process of monitoring and safety of tailings dams presents some hydro-geotechnical complexity. In this context, this research presents a stability study, through numerical modeling of a phosphate tailings dam raised by the centerline method. The modelling framework is based on the knowledge of the groundwater flow and seepage networks, which are applied to verify the safety factor of the structure in two different scenarios: the first considers a high water level (NA) and flooding in the downstream region of the dam and the second considers the execution of works that reinforce and drawdown of the reservoir water level. It is noteworthy that the second scenario complies with premises established by the Agência Nacional de Mineração (ANM) for the stability condition . Thus, this study is based on field and laboratory geological-geotechnicals investigations that were used to support the necessary inputs in the numerical modeling, carried out by the SLIDE software from ROCSCIENCE. From the database analysis, two geological-geotechnical sections were defined, called B-B' and E-E', as being the most representative of the dam under study. To represent the boundary conditions of the model, the average permeabilities of each constituent material of these sections were determined, as well as the elevations of piezometers and water level meters. For the stability analysis, preterits strength parameters are being used, which enabled the analysis of global and partial safety factors in drained and undrained conditions. A preliminary result of the geological-geotechnical section E-E', presents for the first scenario global safety factors equal to 2.06 and 1.32 for the drained and undrained condition, respectively. Partial safety factors equal to 1.96 and 1.32 for the drained and undrained condition, respectively, were found as well. Therefore, the undrained condition, for the first scenario of section E-E', did not meet the recommended in ABNT NBR 13.028:2017, which defines the safety factor greater than or equal to 1.50 for operation with seepage network in normal condition. The next stages of the research aim to compare the results of the first and second scenarios, from both geological-geotechnical sections B-B' and E-E', in order to numerically evaluate the efficiency of the corrective maintenance works performed.

BANKING MEMBERS:
Presidente - DENISE DE CARVALHO URASHIMA
Externo à Instituição - EDUARDO SOUZA CÂNDIDO - UFLA
Externo à Instituição - LUCAS DELEON FERREIRA - UFOP