21 - ANÁLISE ESTATÍSTICA PARA DEFINIÇÃO DE NÍVEIS DE CONTROLE PIEZOMÉTRICOS EM BARRAGENS DE REJEITOS

Doi: 10.47094/COBRAMSEG2026.4/21

PALAVRAS CHAVE: Instrumentação geotécnica, Piezometria, Cartas de controle, Intervalo interquartil, Barragens de rejeitos, Monitoramento estatístico.

KEYWORDS: Tailings dams; Piezometric monitoring; Geotechnical instrumentation; Statistical control charts; Interquartile range; Dam safety monitoring.

ABSTRACT:
This study presents a statistical approach for defining piezometric control levels in a tailings dam under high criticality conditions (Emergency Level 3), focusing on the early detection of groundwater level rise and pore pressure increases. A total of 1,059,382 readings recorded between January 2020 and June 2025 were analyzed, comprising data from piezometers and water level indicators after filtering inconsistent records. The instruments were organized into four groups with similar hydraulic behavior, allowing the application of group-specific criteria. The methodology employs robust statistical metrics based on the interquartile range (IQR) to define upper control limits and progressive attention and alert levels, while the historical maximum value is adopted as a conservative emergency threshold. The results show strong adherence between the proposed limits and the observed hydraulic responses, including extreme rainfall events recorded in 2022 (195 mm in a single day and 1,837.65 mm during the rainy season), distinguishing instruments with rapid response from those with slower hydraulic behavior and supporting preventive dam safety monitoring.

Autores

• Francisco Moreira Mindêllo

• Guilherme de Almeida Silva

• Isabela das Graças Machado

• Lucas Golçalves de Faria

• Rayala Lisboa Masensini