Instability factor analysis and control technology of surrounding rock of soft and thick coal seam ultra-high roadway
The No.2301 fully-mechanized caving face of Anyang Main Coking Coal Mine is arranged along the roof of coal seam along the return airway,but in the process of mining,there are problems of triangular coal loss at the upper end and the coal seam of roadway floor cannot be recovered.For this reason,the advanced floor coal recovery process was proposed,but facing with the problem of sur-rounding rock control of the advanced ultra-high mining roadway.The factors such as high abutment stress,weak coal body,ultra-high roadway,and repeated support from advanced frames lead to severe deformation of ultra-high roadway.Based on the process of floor coal recovery and the deformation and failure characteristics of roadways,the control strategy of active and passive combined supporting,strengthening roadway wall supporting and the combined support method of strong anchor net cable and advanced ultra-high hydraulic support were put forward.The distribution characteristics of plastic zone,displacement and stress field of roadway surrounding rock un-der different abutment stress were analyzed by using discrete element numerical simulation method,and the rationality of supporting scheme was verified.On-site industrial experiments show that measures such as adding anchor rods and strengthening advanced support can effectively control the phenomenon of roadway rib spalling.The use of ultra-high roadway surrounding rock control method can re-cover 24 400 tons of coal resources,with a direct economic benefit of 219 million yuan,and has strong technical and economic prospects.
soft and thick coal seamultra-high roadwaycoal wall stabilizationactive and passive combined supporting