ABSTRACT
Modelling of discontinuous deformation in rock engineering has always been problematic, even though advanced numerical tools are available. The problem stems from the fact that with conventional site investigation it is practically not feasible to know beforehand the characteristics of the discontinuities involved and required for modelling, including the number of joints, their spatial distributions and strength properties as well as their influence on the in situ stress field. Thus, in underground engineering practice, assumptions and simplifications often have to be made in order to apply the relatively less sophisticated continuous modelling and such a practical approach has often proved to be successful. It is believed that apart from the sometimes inherent conservatism of the practical approach, a key factor contributing to the success is the role played by the ground improvement frequently employed by designers to strengthen a jointed rock mass which tends either to transform it into a continuous medium, or to make it behave like a continuous one, or both. In this paper, a case history will be presented to illustrate the practical approach used by the authors, demonstrating in particular the role of ground improvement and its modelling in underground engineering.
