1 INTRODUCTION
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This paper describes the capabilities and limitations of ROCK3DFE - a three-dimensional, static, linear elastic finite element program. ROCK3DFE is designed specifically for mining applications. By implementing a preconditioned conjugate gradient iterative solution procedure, the capability for modelling very large-sized mine structures has been greatly increased and the CPU time has been drastically decreased by several orders of magnitude. Currently, a model consisting of 230,000 8-noded elements (approximately 700,000 equations) will take approximately 6 hours to run on a Digital Alpha Station 200 4/233 with 233 MHz of speed. A state-of-the-art pre- and post-processing scheme has been implemented to accelerate model preparation and analysis of results, thus making the system more acceptable for routine use in ground control and mine planning. A display of source locations of seismic activities has also been implemented. A case history study using ROCK3DFE is briefly described.
ROCK3DFE is a three-dimensional, static, linear elastic finite element computer program for the analysis of structural and geological systems. It is designed specifically for application to mining problems involving the simulation of excavation sequences. An effort has been made to design a program to handle very large-sized 3-D models efficiently and economically with minimal data preparation. Thus the program can be used routinely for ground control and mine planning. Mine structures tend to be very large and complex and are difficult to model numerically. 3-D modelling of underground mines involves significant simplification of geometry and geology. However, over-simplification must be avoided. During the last decade, numerical modelling has gained popularity because of its potential in ground control and mine planning. In response to the industry needs, a number of software packages, such as MAP3D, BEAP3D and EXAMINE3D, have been developed in Canada for handling large and complex 3-D structures [Wiles, 1991, Dieting & Yu, 1988, Yu et al, 1991, Corkum et al, 1991]. These software packages are based on the boundary element method (BEM) because of its efficiency and capabilities for modelling complex geometry of mine structures, in homogeneous and elastic ground. One of the disadvantages for BEM, is the difficulty of handling inhomogeneous rock masses. On the other hand, the finite element method (FEM) can easily incorporate inhomgeneities of rock masses, but the FE programs usually generate a large number of data files and require a large disk space, thus restricting the size of models. Commercially developed software are available but access to these systems is restricted [Bathe, 1993, Femsys Ltd., 1995]. Experience gained over the years indicates that even a very simple 3-D FE model can easily consist of 50,000 brick elements with the solution of approximately 160,000 equations. Even with such a model, many details in simulating, for example, a cut-and-fill mining operation in relatively simple, steeply dipping, narrow and multiple veins, could not be considered. Until recently, the computing time (elapsed clock time) required to run such a model would take 4-5 days for an elastic solution on a Sun Sparcstation 10 [Yu et al, 1995].
