Study of rock movement caused by underground mining in mines with complicated geological conditions

Geological conditions are the basis for surface subsidence. In mines with complicated geological conditions, the displacement and subsidence angles are often forecasted inaccurately, which leads to disastrous consequences. Taking a typical complicated geological mine as the background engineering, and based on the results of surface deformation monitoring for many years, mechanism of surface deformation and rock movement caused by underground mining is analyzed. Results obtained indicate that underground mining is the direct cause of rock deformation, which is significantly influenced by hydrostatic and hydrodynamic pressures of groundwater existing in rock masses. Joint fissures are the foundation of rock deformation. The tectonic stress is the main factor which causes greater movement and deformation. At the beginning of mining, surface subsidence is mainly caused by groundwater drainage. After the formation of large-scale surface subsidence, expansion of gob is the main reason for surface subsidence; but the special engineering geological and hydrogeological conditions have an important influence on the expansion speed of surface subsidence.