Instability Control of Roadway Surrounding Rock in Close-Distance Coal Seam Groups under Repeated Mining

In order to solve the problems of roadway stability and easy instability under repeated mining close-distance coal seam groups, mechanism control technology surrounding rock were studied via indoor testing, field physical similarity simulation experiment, numerical simulation. The results show that has low strength, bearing capacity, poor self-stabilization ability, it is vulnerable engineering disturbances fragmentation. Affected by disturbance mining, cracks are developed sensitivity strong, prone large-scale loose destroyed. location unreasonable, maximum principal stress 3.1 times minimum stress, which quite different. Thus, a large horizontal undergoes long-range expansion deformation. On basis this research, direction emphasis groups in shown. A repair scheme (i.e., long bolt + high-strength anchor cable U-shaped steel grouting) proposed, reduces risk instability.