Discrete element modelling of the buckling phenomenon in deep hard rock mines

Abstract

In deep and high stress hard rock mines, large deformations are often associated with the presence of foliation. Traditionally, the study of the non-linear anisotropic response of foliated rock masses to high stresses and excavations has focussed on the use of continuum numerical modelling methods. This approach, however, has several limitations and fails to reproduce the buckling mechanism observed in underground hard rock mines. This paper presents a methodology for capturing these conditions using the distinct element method. The proposed technique considers the role of fractures within the rock mass and results in the reproduction of the buckling mechanism. This has been achieved by progressive reduction of the forces acting at the boundaries of the excavation by a reduction factor through a series of modelling steps. This approach overcomes the computational and time constraints on modelling the development of a mining drift. The numerical modelling results are in agreement with the observed squeezing mechanism and deformation levels recorded in Canadian and Australian hard rock mines.