Three-dimensional numerical analysis of rock deformation in underground mining excavations ‒ Boukhadra iron mine (Algeria)

Abstract

Purpose. Assessing the stability of underground mine workings excavated in fractured rock masses, deformation and failure of jointed rock masses. Methodology. A numerical model was developed using FLAC3D v6 to reproduce: 1) in situ conditions for the gallery in its natural state without support, 2) the gallery after a geometric modification, and 3) the gallery after installation of a steel set support system. Findings. The application of the proposed method gave a satisfactory result. The results show that the different lithological units exhibit contrasted mechanical responses governed by their physico-mechanical properties. The numerical simulations indicate that some sections of the gallery can remain stable without support, whereas others require reinforcement to ensure safe serviceability. Originality. The use of three-dimensional numerical analysis of rock deformation with FLAC3D v6, and the selection of an appropriate support system to resolve the practical and technical constraints encountered during ore extraction under the conditions of the Boukhadra mine (Tébessa, Algeria). Practical value. Numerical simulations indicate that certain sections of the gallery require reinforcement to ensure their safe operation. Geometric modifications have reduced displacements in these areas, and the installation of steel reinforcement has significantly improved the gallery’s overall stability. As a result, displacements have been significantly reduced in both directions, by approximately 96 and 99 %, respectively.