Research Of Strata Behavior Law And Working Resistance For 42104 Working Face With Fully Mechanized Top Coal Caving Mining At Qing Gang-ping Coal Mine

Fully mechanized top coal caving mining is the main mining method to solve thick and extra thick coal seam mining.This paper studied the Qing gang-ping Coal 4^-2 coal seam which belongs to extra thick coal seam fully mechanized caving mining. Qing gang-ping coal mine had mined the working face 42101, 42102 and 42103 with fully mechanized top coal caving mining, but there were no systemic study for working face strata behavior law and working resistance based on the 4^-2 coal seam surrounding rock occurrence conditions.The related strata control factors affecting the 4^-2 coal seam safety mining were no stematic conclusion.Therefore, it is necessary to carry out research on strata working face behavior law and reasonable working resistance aiming at the 42104 fully mechanized working face.Aiming at coal and rock occurrence conditions at the Qing gang-ping coal mine 42104 working face, this paper has carried out research in-depth research on strata working face behavior law and ZF6800/18/35 support working resistance for the 42104 fully mechanized working face through theory analysis, similar material simulation and field observation means.The research showed that the main roof was made of lower, median and upper three strata for the 4^-2 coal seam. Overall, all kinds of rock compressive strength is in 30MPa⁶0MPa at Qing gang-ping mainfield, which belongs to semi hard rocks.The research has established thin plate mechanical model aming at the 4^-2 coal seam main roof, and obtained the main roof breaking discriminant. Based on this discriminant, we had obtained theoretical limit span of the lower, median and upper main roof. Simulation experiments had showed that the first weighting step of the main foof was 62 m.The first weighting was formed by the lower and median main roof, and the periodic weighting average step distance was 27 m. There was participation of the upper main roof from the beginning of the second period weighting. The periodic weighting average increment of load coefficient was 1.36, and the degree of strata behavior was moderate. Support working resistance monitoring showed that reasonable working resistance of support should be controlled in 8000 k N, and supporting distance ahead of working face should achieve the range of 45 m in front of the coal wall. Field observation had showed that the main foof first weighting step was 57.5m, periodic weighting average step distance was 26.4m, and the working resistance of selecting 6800 KN is reasonable. Referring to similar materials simulation experiment and taking into account the rocks basically belong to semi hard rocks, at the same time, considering universal applicability of support, the working resistance of support should remain in 8000 KN at Qing gang ping coal mine.Research conclusions provided a useful reference for subsequent working and support resistance improvement.at Qing gang-ping coal mine.