Research on theory, simulation and measurement of stress behavior under regenerated roof condition

To determine ground stress behavior under the special condition of a regenerated roof, we established a model of elastic rectangular cantilever thin plates. Moreover, the critical conditions for bending and fracturing the regenerated roof during mining were analysed. Meanwhile, by applying continua FLAC-3D numerical simulation, this research simulated changes in the stress and strain on a regenerated roof during mining and proposed prevention and control methods for dynamic disasters. The results show that: (1) the thinner the regenerated roof, the larger the tensile stress on the roof based on analysis using the theoretical model. Furthermore, the longer the advance distance during mining, the greater the tensile stress on the regenerated roof. (2) By analysing simulation results, during the fracturing of the regenerated roof, roof displacement firstly suddenly increases and then gradually decreases to be stable. Floor-heave-induced displacement presents a divergent state, that is, increases outwards in an elliptical manner. (3) For control of the regenerated roof, monitoring on activities of the roof should be strengthened and stress should be relieved timeously. Moreover, effective support methods should be taken to prevent development of hazards on working faces and roadways caused by the widespread behavior of the roof.