Abstract:

Based on the surrounding rock geological conditions of fully mechanized coal face with sublevel caving and hard roof under fault affected zone in the Jining No.3 Coal Mine, the  supporting parameters of rebar-bolt and cable-bolt supporting for the gob-side tailgate with narrow pillar were designed. With roof-strata-separation instruments and borehole-peep ones, the law of strata behaviors as follows was systematically studied in the process of the driving tailgate. Roof convergence and roof strata separation between inside and outside anchored zone were much smaller. The affected zone in the process of the driving tailgate was about 50 meters. Because of serious floorheave and obvious two ribs convergence, tailgate cross-section has become reversetrapezoid shaped from the  original rectangle  after tailgate deformation. Since there are many more joints and fissures in the pillar of the gob-side tailgate, the coal body was compressed into loose material with block structure from the elastic material with bedded structure. The tailgate cross-section could meet its service requirement and coal face advancement, which demonstrated that the industrial test on rebar-bolt and cable-bolt supporting was successful. Therefore the obtained results were widely applied in the gob-side tailgate of the coal faces in the JNCM

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Key words: coal mine; bolt supporting; tailgate; surrounding rock deformation; strata behavior