深部软弱地层大断面箕斗装载硐室稳定监控分析

Stability monitoring and analysis of large cross-section skip loading chamber in the deep weak stratum

主井箕斗装载硐室处于矿井的咽喉部位,设计断面大、受力复杂、服务于矿井全周期,箕斗装载硐室是否稳定直接影响着整个煤矿的生产运营。采用ANSYS建立箕斗装载硐室的三维地质力学模型,基于FLAC3D模拟分析开挖与支护条件下箕斗装载硐室围岩位移场和塑性区的演化规律,确定锚杆(索)合理的间排距。基于新奥法思想,采用锚杆(索)测力计、压力盒和钢筋计等传感器对深部特大型箕斗装载硐室支护结构的受力状态进行动态监测,初步揭示锚杆(索)轴力、围岩压力(初期支护与二衬间的接触应力)、二衬钢筋受力随时间的演化规律,分析支护结构的工作状态和发展规律,评价现有支护技术方案的支护效果,为进一步优化支护设计奠定基础。监测结果表明,支护结构的受力数值均在安全范围内,尤其是钢筋混凝土衬砌结构的受力状态良好,结构安全可靠,起到了安全承载储备作用;所采用的“锚网索喷初次支护+钢筋混凝土衬砌二次支护”联合支护技术方案,保证了深埋大断面硐室的稳定及使用安全。

As main shaft skip loading chamber is located in the throat of the mine,featuring large design cross-sections,complex stress conditions,and full-cycle service of the mine,its stability directly affects the production and operation of the whole coal mine.The three-dimensional geomechanical model of skip loading chamber was established with the ANSYS software.Simultaneously,the evolution law of the displacement field and plastic zone of the surrounding rock in the loading chamber of the skip were analyzed through FLAC3D simulation.Finally,reasonable distance of bolts(cables)was determined.Based on the idea of NATM,the sensors,including bolts(cables)dynamometer,pressure cell and rebar gauge,were used to dynamically monitor the stress state of supporting structure in deep buried large skip loading chamber.Data have revealed the evolution law of axial force of bolts(cables),surrounding rock pressure(contact stress between the initial support and secondary lining),and stress of secondary lining steel bar.Based on this,the working state and development law of the support structure were analyzed,and the supporting effect of the existing support technology scheme was evaluated,which lays a foundation for further optimizing the support design.Monitoring results have shown that the stress values of supporting structure are within the safe range,especially the good stress state of the reinforced concrete lining structure is outstanding.This phenomenon means that the supporting structure is safe and reliable,and plays a role of safety bearing reserve.The adopted joint support technical scheme of“bolt-mesh-cable-shotcrete for the first time support+secondary support of reinforced concrete lining”can effectively control the deformation and guarantee the safety of deep buried large section chamber.