大倾角煤层切顶成巷顶板结构演化及控制技术
Research on the roof structure evolution and control technology of gob-side entry retaining with cutting the roof in steeply dipping seam
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摘要: 沿空留巷技术在大倾角煤层坚硬顶板条件下的应用一直是一个难题。 基于大倾角煤层 采空区矸石下滑堆积的特点,以充分利用矸石自承载能力为导向,提出了大倾角煤层切顶成巷技 术。 通过理论分析和数值模拟对切顶成巷与传统留巷的顶板结构及围岩应力进行了对比分析, 根据留巷不同阶段顶板的稳定性及变形特点,对切顶工艺和支护工艺进行了优化,并进行了现场 试验。 研究发现:切顶成巷顶板结构处于超静定状态更利于巷道稳定;留巷动压段围岩稳定性最 差;巷道加强支护和挡矸支护可实现协同变形;现场试验巷道顶底板累计变形量为177mm,支柱 支护阻力小于28MPa,支柱未出现明显弯折情况,现场应用取得成功。Abstract: 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.
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