Regional Division and Its Criteria of Mining Fractures Based on Overburden Critical Failure

Mining fracture is the key factor in realizing water-conservation mining, stability evaluation of coal mining subsidence areas, and accurate restoration surface eco-environment. To clarify, evolution distribution fractures, based on strata theory degree overburden failure, contact state rock stratum after critical failure was analyzed, formation mechanism “saddle shaped” water conducting zone revealed, permanent fractures were determined to be primarily concentrated structure at boundary working face. According shear test sandstone zone, damage sample positively correlated with stress, exhibited no instability. Based divided into original fracture, tensile structural void, void compaction areas horizontal direction. The area had largest residual deformation goaf. A regional division method proposed applied engineering by using movement monitoring. results showed that near face greater than middle, goaf closely related time, which has long-term characteristics. rationality also verified.