DEMIN - Departamento de Engenharia de Minas
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/510
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Item Three‑dimensional stability analyses and sensitivity studies of the input parameters in a global failure of an open pit slope : a case study.(2023) Oliveira, Davidson Paulo Azevedo; Lana, Milene SabinoThis work aims to study the parameters afecting a global slope failure in an open pit mine. The event was a complex failure, formed by an upper layer of a weathered rock, which behaved like a soil mass, above two faults, which intersect to form a wedge. This upper soil layer has pressured the wedge leading to its failure. It occurred in the northern sector of the pit in 2013, causing the interruption of mining activity for about 1 year. The geomechanical parameters were defned from an extensive feld survey database; lab tests and Schmidt hammer tests were performed in the region of the failure. The HoekBrown criterion was adopted for the rock mass; Barton-Bandis for the discontinuities and Mohr-Coulomb for the weathered rocks. Three-dimensional limit equilibrium methods were applied using the average strength parameters. The factor of safety (F.S.) was 1.33, a situation which indicated relative stability. Thus, sensitivity analyses were performed to defne the parameters that conditioned the failure, by progressively reducing the discontinuity shear strength via percentage factors, until F.S reached 1.0. Failure surface geometry obtained in the analysis was close to the failure observed at the feld. The susceptibility condition of the wedge failure was evaluated through kinematic analyses in two scenarios; F.S = 1.33 and F.S. = 1. The results indicated a signifcant increase in the probability of kinematic feasibility when F.S. was 1. The reduction of the slope dip should ensure a stable condition. Moreover, the water level should be kept far from the slope face.