Overburden Deformation Rule in Super High Seam Fully Mechanized Caving Mining of Thick Unconsolidated Stratum

It is urgent for westward coal mine development to control surrounding rock of thick unconsolidated stratum, thin basement rock, and super high seam under geological conditions. Studying surrounding rock deformation control mechanism under special geological conditions in western regions is of practical guiding significance for the implementation of China's energy strategy in western regions, with special mining geological conditions of the experimental mine as the background, deformation rule, failure characteristic, and stress distribution characteristic of surrounding rock in fully mechanized caving mining of thick unconsolidated stratum. By establishing the structural mechanics model of "sidestepped rock beam," the stability criterion is determined. The horizontal displacement of surrounding rock in the middle of the working face is small, and the displacement at both ends is large. After the mining of the working face, an "O" ring appears on the main roof. The ring extends outward with the excavation, reaches the maximum at the initial weighting, and its displacement decreases from inside to outside. Finally, through theoretical analysis, experimental research, numerical calculation, and field observation, the thin bedrock and ultra-high coal seam are systematically analyzed, and its deformation and failure mechanism is revealed. Relevant research findings are successfully implemented on the scene and effectively ensured safety, high yield, and high efficiency of the mine.