Use of discrete fracture networks in 3D numerical modelling for stability analysis in open pits

Authors: Montiel, E; Varona, P; Fernandez, C; Espinoza, Z

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DOI https://doi.org/10.36487/ACG_repo/2025_60

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Montiel, E, Varona, P, Fernandez, C & Espinoza, Z 2020, 'Use of discrete fracture networks in 3D numerical modelling for stability analysis in open pits', in PM Dight (ed.), Slope Stability 2020: Proceedings of the 2020 International Symposium on Slope Stability in Open Pit Mining and Civil Engineering, Australian Centre for Geomechanics, Perth, pp. 913-926, https://doi.org/10.36487/ACG_repo/2025_60

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Abstract:
On some occasions, structural mapping in open pit mining presents complications that do not allow for easy data collection. This causes omissions in the consideration of discontinuities (faults, fractures, joints, etc.) whose presence can be of vital importance for the stability conditions presented by the excavation itself. Although many academic articles have based their research on the use of discrete fracture networks (DFN) and how to estimate the joint persistence in a blocky system, projection depths of structures remain ambiguous, even with the information from surveys or drilling. Still, with the interpretation of an experimented mapper, the projection of structure depths could present limitations that would prevent the formation of failure mechanisms that may occur as the project progresses. In order to perform analyses that solve this problem, it has been found that the use of DFNs is considered a tool that allows the incorporation and assessment of the impact of geometric variations of the different structural systems being mapped, thus giving the opportunity to estimate the characteristics of importance in the structural systems as well as their involvement at depth. In order to present the results obtained with the use of these techniques, this article aims to demonstrate that the use of DFNs incorporated stochastically in numerical modelling at the mine scale, along with the method of elements distinctions, this could answer the questions regarding the structural condition of geology in the mine. Through the identification of failure mechanisms, this document intends to show the results obtained in a stochastic 3D evaluation where the use of DFN allows the determination of different geometrical characteristics of the pit and their stability conditions, providing solutions in the definitions of warnings in field monitoring and the validation of the project as it develops.

Keywords: slope stability, discrete fracture networks, failure mechanism, stochastic analysis

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