外文翻译--关于倾角煤层挖掘巷道的锚杆支护的研究.doc

英文原文STUDYONGATEWAYBOLTINGEXCAVATEDININCLINEDCOALSEAMTaoLianjin(陶连金)WangYongjia(王永嘉)ZhanZhuoyuan(张倬元)(NortheasternUniversity,Shenyang110006)(ChengduUniversityofTechnology.Chengdu610059)Abstract：Atypicalgatewayisanalyzedusingfully-deformablediscreteelementmethod.Thefracturedzonearoundthegatewayismeasuredinfield.Basedonthemeasurementresultsandtheoreticalanalysis,acomprehensivesupportschemeadoptingboltandsteelbeltisproposed.Discreteelementmethodisusedtoassestheboltingscheme,anddisplacementmonitoringinfieldisalsocarriedout.Havingbeenputintopractice,itisprovedthattheschemeisbothsuccessfulandrational.Accordingtotheoreticalanalysisandmonitoringinfiled,someimportantkeynotesthatshouldbenoticedingatewayboltingpracticearepresentedaswell.Keywords:inclinedseam；gateway；stratabehavior；bolting；discreteelementmethodIntroductionInclinedcoalseamisgenerallyregardedasseamwithadipsingle2545,whichoccupiesaconsiderableproportioninbothproductionandreservesinChina.Problemsrelatedtostratacontrolare,however,seldomstudied,andresearchesonin-seamgatewayareeven1less.Themaintenanceexpenseofgatewayininclinedseamisgenerally30%higherthanthatinnearlyflatandgentlyinclinedseam.Thereasonwhythereexistsasuchphenomenoniscomplicateditself,anotherpossiblereasonisthelackoftheinherentstratabehaviorlaw.Atpresent,problemsrelatedtoin-seamgatewaymaintenancearehighlyemphasizedandmanystudiesonstratabehaviorandsupportofgatewayarecarried24out.Suchresearchesplayapositiveroleingatewaymaintenance.Howevermostoftheresearchesarecarriedoutinflatorgentlyinclinedseams.Duetotheirlocatinginremarkablyanisotropicmediaandenvironment,gatewaysininclinedseamsareoftensubjectedtounfavorableloadsanddeformunevenly,stratamovemoreintensivelythanthatingentlyinclinedseam,andthebrokenregionisalsolarge,whichmakesgatewaysupportevenmoredifficult.Inviewoftheabove-mentionedfacts,weusefullydeformablediscreteelementmethodinsimulatingstratabehaviorofgatewayininclinedseam,andtheloosedzonearoundthegatewayisalsomonitoredinfield.Basedontheresults,aboltingschemeisproposed.Afterputtingintopractice,theschemeisprovedtobeeffectiveandrational.1.Deformandfailfeaturesofgatewaywithoutanysupport1.1GeologicconditionsThestudyobjectistheNo.36seaminBaoshanCoalMine,thedipangleoftheseamis35andthicknessis1.0m,thegeologicconditionsarerathersimple.Theaverageburieddepthis440m.Theimmediateroofis2metersthickoffinesandstoneandshale,theoverallstrengthislow.Abovetheimmediateroofiscomparativelyhardmainroof.Thefloorisfinesandstone.Thegatewaywidthis2.2mandthegatewayisexcavatedinirregularshapeinordertokeeptheroofintact.Thesidewallcoalishoweverrathersoftandloose,andeasilyfails.Thesurroundingrocksofthegatewayarenotstable,roofandsidewallareapttofallorbreak,whichisdangeroustobothproductionandhumansafety.Theworkingfaceoftenstoppedduetodifficultmaintenanceofthegateways.1.2SimulationofgatewaydeformationandfailurewithdiscreteelementmethodThejointstatisticalresultsshowthatthesurroundingrocksofthegatewayarecutbytwoorthogonaljoints,onegroupisthebeddingplaneofthecoalmeasures,anothergroupisnormaltothebeddingplane,mainlydevelopedintheimmediateroof.Becauseofthelowstrengthofimmediateroof,thereoftenexistlongjointsthatcrossthroughtheimmediateroof.Suchlongjointsplayadominantpartinrooffalling.Accordingtothespatialdistributionofjoints,adiscreteelementmodelisbuiltasshowninFig.1.Thecomputingparametersrequiredaremainlybasedonmeasurementinfieldandsomebackanalysis.Theloadappliedtothemodelaregravitationalstressfield.Thediscreteelementsarefullydeformablesothathedeformationofblockcanbeinvolved.Afterthegatewayisexcavated,undertheactionofinitialstresses,theuppersidewallcoalfirstlybreaks,thenthesurfaceofthelowersidewallcoalbeginstoyield.Theabutmentsoftheroofatthetwosidewalltransfertodeepsolidcoalinconsequence.Theimmediateroofatthesurfaceofthegatewaybeginstobend,beddingseparate,failandfall(seefig2),asaresult,largeareaoftherooffallsuntiluptothemainroofSomebrokenblocksmaycollapsewhenasmalldisturbanceoccurs,Inthepracticalface,itisverydifficulttodealwiththefallenrocks,sometimesachaincollapseofupperimmediateroofmayoccurifspecialattentionisnotpaid,whichmakesthefallenrockdisposaladifficultanddangeroustask.Theresultsindicatethattwosidewallcoalsfaildifferentlytheuppercoalbreaksmoreintensivelythanthelowersidewallcoal.Accordingtotheabove-mentionedanalysis,itcanbeseenthatinmiddletolowlyhardthininclinedseam,thestabilityofthetwosidewallcoalsisveryimportanttotheoverallstabilityofthegateway.Ifthesidewallfails,thentheabutmentsoftheroofwilltransfertodeepsolidcoal,asaresultthefreespanoftheroofincreases,whichaggravatestheunstableconditionofthewholegateway.Suchfailureofsurroundingrocksisevenseriouswhenitissubjectedtomininginfluence.Itis,thusthekeytokeepthesidewallsolidandintactinordertokeeptheoverallstabilityofgatewayininclinedseams.2.MeasurementofloosedzonearoundgatewayBasedonloosedzonetheoryofexcavation,aloosedzoneisgenerallyformedaroundtheexcavationifwhichthestressislowerthantheinitialstress.Owingtoirregularshapeofgatewayininclinedseamandanisotropicmedia,theloosedzonearoundgatewayiscertainlyinirregularshape.Weuseanultrasonicjointdetector(TypeSC-IIbyFushuninstituteofCoalScienceandTechnology)tomeasuretheloosedzoneofthegateway.ThetestresultsareshowninFig.3.Thegatewaywassupportedbytworoofbolts1.6mlongwithveryslightlyprestressed.Themeasuredloosedzoneisuppersidewallcoalmorethan1.8m,lowersidewallcoal1.4-1.5m,andtheroofis0.95-1.1m.Thegatewaycanbestablewithoutmininginfluence.Butaslongasbeingsubjectedtominingactivity,thegatewaywillcollapsewitsidewallfailingandrooffalling.Inextremecase,themaximumcavingheightcanreachashighas4.0m.Asaresult,thegatewayintheseamisverydifficulttobemaintainedandthemaintenancecostisthusratherhigh.Thetestresultsarecoincidedwiththenumericalcalculation.Soitis,therefore,necessarytoreinforcethegatewayincludingthesidewallcomprehensively.3.Inclinedcombinedbeammode