Characteristics of overlying rock migration and law of rock pressure behaviors at filling working faces
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.
filling working faceoverlying rock migrationequivalent mining heighttime effectboundary effect
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