Determination of support working resistance in the working face of extremely-thin coal seam based on overburden fracture characteristics
Extremely thin coal seam is widely distributed in Zichang mining area of Yan'an.The coal is scarce in China with coking coal,and the recovery value is high;however,the mining area has no prec-edent of mining extremely-thin coal seam,and the problem of unreasonable support selection is faced in the mining process,and there are few research results in this aspect in China,so the mining face of ex-tremely-thin coal seam in Hecaogou No.2 coal mine was taken as the research object,the fracture char-acteristics and evolution process of roof overburden structure of fully-mechanized mining face in ex-tremely thin coal seam were analyzed by means of numerical simulation and theoretical analysis,and the mechanical analysis model before and after the fracture of roof rock beam was established.And a direct roof periodic fracture distance of fully mechanized mining face in extremely thin coal seam was obtained,with the reasonable working resistance of support determined.The results show that the over-lying rock could be supported quickly after the roof caving in the early mining stage of the very thin coal seam face;after reaching the limit span of the roof,the direct top and basic top break periodically,and the basic top break position is in front of the direct top break line;there is a separation space be-tween them,and they turn and sink together.The hydraulic support of the working face is mainly affect-ed by the direct top rotating load;its working load is 3 980.89 kN,and the support selection is deter-mined to be ZZ4000/6.5/13D four-column support and cover hydraulic support.By on-site testing,the support performance can be effectively utilized to meet the surrounding rock control requirements of the stope.The research results provide a certain reference for the support selection of the mining face of ex-tremely-thin coal seam in China.
extremely-thin coal seamfully-mechanized mining faceroof structure evolutionsupport-surrounding rock interactionsupport working resistance
万方数据
维普
