Some issues in modelling of ground support using the three-dimensional distinct element method

Abstract

Numerical models are an integral part of the rock engineering arsenal that are applied to a wide range of practical problems. The choice for a particular numerical code is based on the capacity of a code to represent the boundary conditions, adequately capture the material behaviour and capture the pertinent failure mechanisms. It follows that there could be more than one code suitable for a particular problem. In this respect, the choice for a code will be dictated by a series of technical and practical trade-offs. This paper addresses issues associated with the explicit simulation of jointed rock mass and ground support in numerical models. Although various types of ground support elements have been implemented in most numerical analysis software packages, their practicality and applicability for realistic simulation of ground support have not received a high level of technical scrutiny. This paper focuses on explicit simulation of a jointed rock mass and ground support using the three-dimensional distinct element code (3DEC), which is based on the distinct element method (DEM). The calibration of the numerical model was conducted with reference to the results obtained from instrumented trials at the George Fisher mine, Queensland, reported by the Australian Centre for Geomechanics. In particular, the investigation considers the response of the ground support system, consisting of both reinforcement and surface support elements to the excavation of nearby stopes. It was demonstrated that the DEM model was capable of realistically simulating the ground deformation and the support behaviour monitored at different stages of mining cycles.