Research on the roof structure evolution and control technology of gob-side entry retaining with cutting the roof in steeply dipping seam

Theapplicationofgob-sideentryretaining(GER)insteeplydippingseamwithhardroofhas alwaysbeenadifficultproblem.Basedonthecharacteristicsofgangueslideaccumulationingobwith steeplydippingseam,aimatmakefulluseoftheselfbearingcapacityofthegangue,thetechnologyof thegob-sideentryretainingwithroofcutting(GERRC) insteeplydippingseamisproposed.Through thetheoreticalanalysisandnumericalsimulation,theroofstructuresandsurroundingrockstressesofthe GERRCandthetraditionalGERwerecompared.AccordingtothestabilityanddeformationcharacteristicsofroofindifferentstagesofGEERC,thecuttingangleandsupportingtechnologywereoptimized, andfieldtestswerecarriedout.Thisresearchfindsthat,whentheroofstructureoftheGERRCisina staticallyindeterminatestate,itismorefavorableforroadwaystability.Thestabilityofthesurrounding rockinthedynamicsectionistheworst.Roadwaystrengtheningsupportandblockingganguesupport can be coordinated with the roof deformation.The field tests were successful.The cumulative deformationoftheroofandflooris177mm.Thesupportingresistanceofpillarsislessthan28MPa withoutobviousbendingpillars.