Deformation and failure law of coal roadway supported by concrete filled steel tube supports in Nanguan mine

TakingthecoalroadwayinNanguanmineofFenximiningareaastheprototype,relyingon thenestedsimilaritysimulationexperimentalsystem,thephysicalsimilaritymodelwasestablishedto studythestressdistribution,displacementanddeformationfailurecharacteristicsofthesurroundingrock ofcoalroadwaysupportedbyconcretefilledsteeltubesupport.FLAC3D5.0softwarewasusedtoestablishthecalculationmodelofconcretefilledsteeltubesupportroadway,whichsimulatedthedepthof 100mto1000mrespectively;thedeformationandfailurelawofcoalroadwayandthecharacteristicsof supportstresswereanalyzed.Theresultsshowedthat,concrete-filledsteeltubesupportcanimprovethe radialsupportpressureofroadway.Attheinitialstageofloading,thestabilityofroadwayismaintained, however,with the increase of load,the convergence of sidewall is greater than that of roof and floor.Fissuresfirstappearinthesidewallanddeveloptotheroofandfloor,thenthesidewallandthe roofareunstablesuccessively.Itcanbeseenthatthesidewallistheweaklinkofsupport.Undertheactionofconcretefilledsteeltubesupport,thestressdistributionontheroadwaysurfaceisserrated,which indicatesthatthesupporthasaneffectivesupportrangeforsurroundingrock,andthesupportbetween thesupportsisalsotheweakpartofthesupport.Theaxialforceandmomentofthesupportcasingare larger,andthecasingiseasytobedamaged,whichleadstothelossofthebearingcapacityofthesupport.ItcanbeseenthatthekeytoensurethestabilityofconcretefilledsteeltubesupportinNanguan mineistocontrolthedeformationandfailureofsidewallandsupportcasingandtoimproveitsstrength.