Prediction of Collapsing Region Above Deep Spherical Cavity Roof Under Axis-Symmetrical Conditions

Excerpt

Sudden collapse of the rock mass above a deep cavity roof is a common occurrence in underground construction. The reason for this is that the original stress field has been perturbed by the underground excavation, which causes redistribution of stress and the formation of a secondary stress field. This transformation causes this part of the rock mass to break away from the whole rock mass system, resulting in a local collapse of the cavity roof. Furthermore, spherical cavities are common in underground construction, being widely used in underground spherical tanks, silos, and bunkers. To ensure the safety of oil or other dangerous goods stored in such underground silos, these cavities need to be excavated in deep rock strata. So, prediction of the collapse region of deep cavities is an issue of great engineering significance. …