Study on technology of sub-regional differential repair of broken surrounding rock under dynamic pressure

In order to solve the problem of stability maintenance of broken surrounding rock under dynamic roadway, the extension of the No.2 coal mine transportation roadway of Heilong Coal Mine was taken as the engineering background,By means of field measurement, theoretical analysis, numerical simulation and industrial test, the deformation and failure characteristics of surrounding rock of the roadway were analyzed. The deformation and failure characteristics of the surrounding rock of the roadway were studied, and the stress evolution of the single mining support and the superposition effect of the repeated mining stress were also analyzed. The main influencing factors and influence laws of the large deformation of roadway surrounding rock under dynamic pressure were summarized and the deformation instability path of surrounding rock in the roadway was also revealed: the test roadway is under high stress environment after the mining roadway is activated. When the adjacent roadway is activated, it reveals that the mudstone strength is low. The original supporting structure is not enough to control the crushing deformation and induce large deformation of the roadway..At the same time, due to the unreasonable design of stop-mining line, the local roof collapse occurred under the influence of the superimposed stress of working face,which seriously affected the safety production of the mine. To this end, the stability control path of surrounding rock in the dynamic pressure main roadway is proposed: making full use of the bearing capacity of the fine-grained sandstone rock stratum (top plate) with high strength and thick rock layers, optimize the supporting parameters and control the position of the stop line, prompting anchor rod (cable) and surrounding rock formation bearing structure, improve the stress environment of the roadway, and maintain the stability of the surrounding rock. Finally, the sub-regional differential repair technology of dynamic pressure-prone roadway is proposed, and the surrounding rock control technology system with "improving stress environment + high-strength and high-prestress support + bottom angle support + lagging grouting" as the core was formed. and it has been successfully applied to on-site industrial tests. The results of mine pressure monitoring show that the technology has achieved good surrounding rock control effect, ensured the safe and efficient production of the mines, and provided a certain reference for similar conditions of roadway support and repair.