Control Mechanism of Surface Subsidence and Overburden Movement in Backfilling Mining based on Laminated Plate Theory

The backfilling mining technology is a type of high-efficiency coal mining technology that is used to address the environmental issues caused by the caving mining technology. In this paper, the mechanical model of symmetrical laminated plate representing the overburden movement caused by the backfilling mining technology is established, and the governing differential equation of the motion of the overburden is derived. The boundary conditions of the mechanical model are put forward, and the analytical solution of the overburden movement and surface subsidence is obtained. The numerical model of the overburden movement and surface subsidence, under mining with backfilling, is established by means of the FLAC3D numerical software, which aims to systematically study the influence of backfilling compactness, mining thickness, and mining depth on the overburden movement and surface subsidence in backfilling mining. When the compactness eta is less than 70%, the overburden movement and surface subsidence is greater, while when eta is greater than 70%, the overburden movement and surface subsidence is reduced significantly. On this basis, the control mechanism of surface subsidence and overburden movement in backfilling mining is obtained. The suitable backfilling compactness is the key to controlling surface subsidence and overburden movement in backfilling mining.