Failure Mechanism and Control of Surrounding Rock of Mining Roadway Under Overlying Goaf

Aiming at the deformation and failure of roadway surrounding rock and its control problems under goaf in upper and lower coal seam mining of Buertai Coal Mine, the distribution characteristics of surrounding rock stress in different mining stages of goaf were analyzed, the evolution law of plastic zone of roadway surrounding rock under goaf was analyzed, and the failure mechanism of roadway surrounding rock was revealed by theoretical calculation and numerical simulation.The results show that: the principal stress of the mining roadway under the goaf is smaller than that of the original rock stress. The plastic zone of surrounding rock is small during excavation. Affected by the first mining, the maximum principal stress is 1.24 times of the original rock stress, and the minimum principal stress is 1.49 times of the original rock stress. Affected by the secondary mining, the maximum principal stress is 1.52 times of the original rock stress, and the minimum principal stress is 1.74 times of the original rock stress. In order to control the malignant development of surrounding rock plastic zone, the staged support technology in different mining stages is proposed, and the stress environment of surrounding rock is improved by hydraulic fracturing, so as to reduce the plastic zone of surrounding rock and maintain the safety and stability of surrounding rock.