Prediction of underground cavity roof collapse using the Hoek-Brown failure criterion

Preventing roof collapse in underground cavities is a challenge to geotechnical engineering. In this study, three independent methods have been used to evaluate the roof collapse of underground rectangular cavities for a range of geometries and rock properties. The rock mass strength has been described by the Hoek-Brown failure criterion. The results of the analysis allow for prediction of roof collapse and to determine whether the failure surface that develops in the rock mass remains localised or extends through the full depth of cover. This is of significance if there are overlying cavities and when estimating surface subsidence.