A computer method for stability analysis of caverns in jointed rock

A simple rigid block model has been developed for analysing the stability of caverns and tunnels in jointed rock. Rigid block interactions are idealized as linear edge-to-edge contacts with a zero joint tension constraint and a mohr-coulomb friction law. In the method, the minimum friction angle for stability is determined by sequentially eliminating tension and then minimizing the shear. It is demonstrated through examples that the minimum joint friction angle which results in a stable configuration is independent of the stiffness of the joint, and depends only upon the loading and geometry of the jointing and cavern. This insensitivity of stability to the normal and tangential joint stiffnesses, which can be difficult to obtain, is very useful for design purposes. (Author/TRRL)