Study on roof collapse of deep circular cavities in jointed rock masses using adaptive finite element limit analysis

This paper investigates the roof collapse of deep circular cavities in jointed rock masses using adaptive finite element limit analysis. The rock mass strength is described by the generalized Hoek-Brown failure criterion. The calculated results of the stability number N-s are presented in the form of dimensionless stability charts and are compared to the transformational results of an analytical upper bound solution by former investigators. The transformations are conducted using an algorithm proposed in the appendix of this paper. Parametric studies are performed to investigate the impacts of the Hoek-Brown parameters on the stability number and failure mechanism of underground cavities. In particular, different levels of rock mass disturbance are considered by adopting various rock mass disturbance factors D in the analyses.