Investigation of catastrophic ground collapse in Xingtai gypsum mines in China

Mining-induced ground collapse brings about harmful results to environment, fatality and property losses. In particular cases, there is lack of forewarning that a catastrophic collapse will occur in minutes. Therefore, a better understanding of the behavior and stability of ground strata in mining is of significant importance to improve mining design, to monitor the situation of the rock strata and, if it is possible, to forecast the catastrophic ground movement. In the presented work, a large-scale ground collapse in the Xingtai gypsum mines has been investigated through site measurement together with theoretical and numerical analysis. The collapse induced a strong air shock and severe failure of rock strata. From the technical points of view, the investigation covers the calculation of air shock intensity, the analysis of the pillar instability and the fracture process in the roof strata in terms of a plate seated on an elastic foundation. A few mechanical models have been proposed and discussed in detail. Finally, the essential and key factors that resulted in the catastrophe are elaborated by means of comprehensive studies.