Optimization of terminal mining position and stress control technology for roadway protection in fully mechanized mining faces

XIE Zhichao; GUO Jiangfeng; LIU Zishuo; HAN Lijun; GAO Peng

doi:10.11799/ce202602002

Abstract：During the final mining stage of a working face,the advance abutment pressure ahead of a fully mechanized face continuously exerts adverse effects on the adjacent main roadway,leading to stress concentration in the surrounding rock and increasing the risk of instability.Therefore,taking the 22104 working face of Yaping Coal Mine in Shanxi as an engineering case,we first analyzed the roof fracturing distance and the characteristics of the overburden structure based on the key stratum theory.Then,we applied FLAC3D to simulate the deformation and failure process of the surrounding rock in the main roadway under the progressive influence of face mining,enabling a reduction of the protective coal pillar width to approximately 55 m.To provide sufficient safety redundancy,a combined pressure-relief and grouting reinforcement technology was proposed,consisting of"excavating a separate pressure-relief roadway and pre-grouting reinforcement on both sides."This approach simultaneously achieves pressure relief through the excavated roadway and reinforcement of the coal-rock mass for pressure control,thereby improving the stress environment around the main roadway.The deformation and failure of the main roadway under both"pressure-relief only"and"combined pressure-relief and grouting"conditions were simulated.The results show that this reinforcement technology can effectively reduce the risk of instability in the main roadway surrounding rock.The proposed scheme was implemented on-site,which maintained the main roadway stability three months after the working face stopped mining,demonstrating favorable application results.