充填工作面覆岩运移特征与矿压显现规律研究

Characteristics of overlying rock migration and law of rock pressure behaviors at filling working faces

充填开采与传统垮落法开采覆岩运移特征明显不同,为探讨充填工作面覆岩运移特征和应力分布规律,基于厚板理论建立了考虑充填体对顶板支撑作用的力学模型,分析了充填工作面覆岩运移的时间效应和边界效应,并在运河煤矿C5301工作面进行支架阻力、微震事件和钻孔应力等监测,分析了充填工作面矿压显现规律。结果表明:顶板最大挠度主要受采空区短边宽度影响,而充填工作面等价高度限制了顶板下沉范围,由于充填体随着工作面的推进逐渐被压实,顶板的下沉在时间上表现为明显的滞后性,通过建立考虑充填体对顶板支撑作用的力学模型,得到了顶板最大挠度随时间变化的函数;通过支架阻力监测可以得到,初次来压步距约为200 m,周期来压步距约为12~17 m,超前支承压力影响范围为91~97 m,采空区顶板运移呈现出明显的时间效应和边界效应。

It is obvious that migration characteristics of overlying rocks between filling mining and traditional caving is different.To explore the migration characteristics and stress distribution of overlying rocks at filling faces,a mechanical model considering the support effect on filling in roofs was established based on the thick plate theory.We analyzed the migration duration and boundary effects of overlying rocks at filling working faces,and tested support resistance,microseismic events,and borehole stress monitoring at No.C5301 working face at Yunhe Coal Mine,which shows behaviors of rock pressure at filling faces.The results indicate that the maximum deflection of the roof is mainly affected by the width of the short side of goafs,while the equivalent height at the filling face limits the range of roof subsidence.Due to the gradual compaction of the filling body as the working face advances,the subsidence of the roof shows a significant lag time.By establishing a mechanical model considering the support effect on the filling body in roofs,a time-varying function of maximum roof deflection is obtained.In terms of monitoring support resistance,the initial weighting interval is about 200 m,the periodic weighting interval is about 12~17 m,and the influence range of advanced support pressure is between 91~97 m.The movement of goaf roofs presents significant time and boundary effects.