Abstract: In view of the mutability in deformation and failure of the rock mass, and combined with the theory of the material mechanics, a cusp catastrophe model of rock beam-pillar was build. The destabilization mechanism of pillar was analyzed, and the conditions and energy of system failure also were found through the model. The research results show that the stability of rock beam-pillar depends on the mechanical geometry characteristic of the system, and it has nothing to do with the external factors. Finally, with a gold mine as a case, the rationality of selecting the structural parameters of stope were analyzed and judged through the instability condition of system.

Key words: Rock beam-pillar, Catastrophe theory, Instability and failure