Banca de QUALIFICAÇÃO: DANIELLE FERREIRA MAGALHAES

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : DANIELLE FERREIRA MAGALHAES
DATE: 24/06/2022
TIME: 18:00
LOCAL: Araxá - MG
TITLE:

GEOTECHNICAL STABILITY ANALYSIS OF PHOSPHOGYPSUM STACK

KEY WORDS:

Phosphogypsum, Instrumentation; Monitoring; Stack; Dam; Stability.

PAGES: 25
BIG AREA: Engenharias
AREA: Engenharia de Minas
SUBÁREA: Lavra
SPECIALTY: Lavra a Céu Aberto
SUMMARY:

The present work aims to analyze the geotechnical stability of a phosphogypsum stack located in the State of Minas Gerais, using geological-geotechnical data obtained through laboratory and field investigations, as well as information obtained through monitoring instruments of the respective geotechnical structure, highlighting: surface landmarks, piezometers, water level indicators, outlets, among others. In this way, it is possible to observe the displacements, underpressure, water table, seepage flows, deformations of the massif, levels of insitu stresses and permeability coefficient, thus making it possible to assess whether the analysis of geotechnical stability should be done in terms of total stresses (undrained parameters) or in terms of effective stresses (drained parameters). The field investigation campaign consists of SPT, CPT, CPTu tests and permeability tests. The conventional laboratory tests used were: granulometry, real grain density, natural density, maximum and minimum void index, consistency limits (Atterberg), moisture content and simple compression. The special laboratory tests used were: consolidation, direct shear (saturated and unsaturated) and triaxial tests (CD and CU). The case study of this work started its activities in 1979. The project was initially conceived to have 85 meters. Currently, the highest section of the stack is already about 85 meters high and has an estimated area of 160 hectares, values that are reviewed annually by the mining company's project team. For the sectorization of the critical section of the slope of the stack in this research, the steepest cross-section was used, with conservative geotechnical parameters. The stability method adopted for the present research was the General Limit Equilibrium Method proposed by Morgenstern and Price. Its choice is due to its physical-mathematical rigor that makes it possible to carry out an analysis in terms of balance of forces and moments at the same time. This work also discusses the magnitude of the geotechnical parameters (cohesion, friction angle, specific weight and permeability coefficient) obtained in the researched databases. Therefore, a sensibilistic analysis will be carried out, presenting their most probable values. The choice regarding the theme of this work was motivated by the search for an understanding of the behavior of a unique geotechnical structure in Brazil that until then was classified by the supervisory bodies as a dam, and recently reclassified as a drained stack.

BANKING MEMBERS:
Interno - THIAGO BOMJARDIM PORTO
Interno - HILDOR JOSE SEER
Interno - ALLAN ERLIKHMAN MEDEIROS SANTOS
Externa à Instituição - TEREZINHA DE JESUS ESPOSITO BARBOSA - UFMG