Rib Spalling Mechanism and Control with Fully Mechanized Longwall Mining in Large Inclination 'three soft'Thick Coal Seam under Closed Distance Mined Gob

摘要

Rib spalling in "three-soft" thick seam with fully-mechanized and large height mining is difficult to control, especially under closed mined gob, and still is a main safety hazard.Based on geological conditions of No.12124 longwall panel in PanBei Coal Mine and its strata behaviors during initially extracting, characteristics and factors of coal spalling have been investigated with lab experimental analyzing,theoretical calculating, and computer simulating with FLAC3D.Strata behaviors, such as modes of coal wall spalling, mining-induced stress evolution characteristics, deformation and breakage area, have been systematically analyzed and obtained during the No.12124 longwall panel advancing after the No.12125mined.Coal properties, abutment pressure superposition of multiple-seam mining and performance of hydraulic support are the key factors to result into rib spalling.And the rib spalling mechanism with multiple mining-induce stress superposition in closed distance seams under complex geological conditions has been revealed.To increase support resistance, infuse water into coal, and pave double mesh networks, were combined and put forward to control rib spalling.Engineering practice show that three technologies application have been achieved safe-effectiveness and provided references for longwall panel layout, spalling control, and hydraulic support design in similar geological conditions.