A study of the development regularity and formation mechanism of ground subsidence in shallow coal seam mining of Yangchangwan coal mine, Ningxia

The mechanism of ground subsidence induced by coal mining is an important theoretical basis for the prevention and is also one of the hotspots in the study of geological environment. Subsidence type, features and the mechanism were studied by methods of the UAV remote sensing technology, field observation and numerical simulation software on the Y110207 working face in Yangchangwan coal mine, Ningxia. The results show that, during shallow coal seam mining, cracks and surface collapses are developed, which cause ground surface destruction. In the working face, the parallel cutting cracks are distributed with an interval distance between 10~120m. The parallel channel fracture is a tensile fracture, which is developed in a certain range from the trough to the periphery. The coal mining activities lead to the move and destruction of the overlying strata. The damage can be divides into three types, i.e., shear failure zone, tensile failure zone and shear-tensile failure zone, corresponding to compressive stress region, tensile stress zone and compression tensile transition zone. When the stress is more than the tensile strength of the covering layer transferring to the surface, the cracks will occur. With the advancing of the working face, the water flowing fracture zone will develop to the surface. After that cracks will perforate and the staggered platform will emerge. It enriches the theoretical knowledge of ground subsidence in shallow coal seam and provides a theoretical for the prevention.