Retroanálise de ruptura global de taludes ocorrida na Mina Uruguai – Minas do Camaquã/RS

Abstract

Geotechnical analysis has been increasingly applied in the design of projects as well as in the optimization of already completed works, in order to guarantee local safety and reduce future expenses, whether in the context of civil construction or in mining activities areas. This work aims to address the issue of slope stability in order to define the structural causes of a global slope failure that occurred in the Minas do Camaquã (RS), specifically at the pit of the Uruguay Mine. With a back analysis, the slip mechanism was characterized, besides the analysis of the conditions that allowed this result such as: presence of water, joint strength, external forces, large geological structures, among other factors. Due to the impossibility of access to the failure site, the aero photogrammetry feature was employed by means of UAV (unmanned aerial vehicle), which allowed the obtaining of geotechnical information from the images and 3D models produced in the Metashape software. The joint planes obtained by the 3D mapping were identified from Micromine software and later plotted on a stereogram using Rocscience Dips software, where it was possible to classify the failure as wedge type. Subsequently, the safety factor for the identified failure was calculated using SWedge software. In the same software, a sensitivity analysis was performed, varying the input parameters, such as presence of water and joints strengths. As a result, it was possible to identify the principal structures, as Piritas Fault and another Normal Fault with a vertical dip. The intersection of these two structures form a wedge in which the failure occurred. The safety was analyzed, and the current slope dip is below the angle of repose for rocks, ensuring stability. These conclusions together with the methodology employed, becomes the main contribution of the work, making it possible to use it as a basis for similar case studies in back-analysis of slope failures.