Research on the deformation and failure law and control technology of surrounding rock in the dense roadway area in footwall of normal fault

To solve the problem of large deformations and failure of rocks surrounding a dense area at the footwall of a normal fault, we considered the F22 fault in the fourth mining area of Dashucun coal mine in Hebei Province as the research object and conducted onsite investigations of hidden dangers, such as roof caving and wall caving over the roadway. The deformation and failure law of the surrounding rocks was obtained using the FLAC3D numerical simulation method, and the factors influencing such deformation and failure were analyzed. Consequently, the advanced support of the working face and support scheme for the dense roadway area were optimized. After implementing these programs, the results showed that with the exception of the belt rise, where the deformation of the surrounding rock was affected to some extent, the roof subsidence and approach of two gangs in the dense roadway areas could be controlled to within 220 mm and 320 mm, respectively. Hence, we proved that the surrounding rock conditions in the dense roadway area met the needs of the project.