大采高工作面覆岩运移特征及支架可靠性分析

Research on overlying rock migration characteristics and support reliability of large mining height working face

针对大采高工作面回采中可能存在的覆岩垮落压死支架及冒顶风险,采用现场监测与数值模拟相结合的方法对覆岩运移特征及支架可靠性进行了系统分析。结果表明:随回采工作面推进,支架压力表现为两侧低中间高变化特征,周期来压持续时间长、步距短,滞后工作面20 m处,微震事件频率最高,此时顶板活动最为剧烈,需要引起足够重视;随工作面推进,基本顶及其上覆岩层表现为周期性断裂特征,基本顶与主控层之间覆岩呈现整体性运移特征。理论计算得到支架工作阻力为10024 kN,该参数值为额定工作阻力的66.8%,满足顶板支护强度要求,可保证工作面安全回采。

In view of the possible risk of overburden caving and roof collapse in large mining height working face,the migration characteristics of overburden and the reliability of support are analyzed systematically by the method of field monitoring and numerical simulation.The results show that,with the advance of the stope face,the support pressure presents the characteristics of low on both sides and high in the middle,and the duration of periodic pressure is long and the step distance is short.When the working face lags 20 m,the frequency of microseismic events is the highest,and the roof activity is the most intense,so it needs to be taken seriously.With the advance of the working face,the basic roof and its overlying strata show periodic fracture characteristics,and the overlying rocks between the basic roof and the main control layer show integral migration characteristics.The theoretical calculation results show that the working resistance of the support is 10024 kN,and the parameter value is 66.8%of the rated working resistance,which meets the requirements of roof support strength,it can ensure the safety of working face mining..