采矿工程中英文对照外文翻译文献Word文档格式.docx

采矿工程中英文对照外文翻译文献Word文档格式.docx

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Softrockengineeringisadifficulttopicwhichhasreceivedmuchattentioninthefieldofrockmechanicsandengineering.Researchandpracticalworkhavebeencarriedout,butmuchoftheworkhasbeenlimitedtosolvingproblemsfromthesurface.Forovercomingthedifficultiesoflargedeformations,longdurationtime-dependenteffects,anddifficultiesinstabilizingthesoftrock,theproblemshouldbetackledmoreradically,leadingtoamoreeffectivemethodofachievingoptimizationoftheengineeringsysteminsoftrock.Asummaryoftheoptimizationprocedureismadebasedonengineeringpractice.

1.Introduction

Therearemanysoftrockengineeringproblemsaroundtheworld,involvingengineeringformines,highways,railways,bridges,tunnels,civilsubways,buildings,etc.Engineeringlosseshaveoccurredbecauseofvolumetricexpansion,lossofstabilityofthesoftrock,etc.Thishasbeenanimportantquestiontowhichmuchattentionhasbeenpaidinengineeringcircles,andinthefieldofacademicrockmechanics.Sincethe1970s,considerableresearchandpracticaleffortshavebeenmadeinthefieldofsoftrockengineeringinvariouscountries,butthemajoreffortswereconcentratedonsuchaspectsasthemethodofconstruction,thedesignandreinforcingofthesupportingstructures,measurementandanalysisoftherock’sphysicalandmechanicalproperties,itsconstitutiverelationsandengineeringmeasurement.

Ithasbeenfoundthatthesoftrockengineeringprobleminvolvescomplexsystematicengineeringincludingsuchsubsystemsasclassificationofsoftrocks,judgementconcerningthepropertiesofsoftrock,projectdesignandconstruction.Onlybyconsideringtheintegraloptimizationofthesystemcanweobtainanimprovedsolutiontotheproblem.Hopefully,aradicalapproachcanleadtoengineeringfeasibility,lowercostsandengineeringstabilityinordertoachievetheengineeringobjectives.

1.1.Mechanicalpropertiesofsoftrockandassociatedengineering

Softrockisanunevenanddiscontinuousmedium.Itsstrengthislow,withauniaxialcompressivestrengthusuallylowerthan30MPa.Somesoftrocksexpandwhentheyarewet.Cracksinsomesoftrockswillpropagateeasily—whichmakesthemexhibitvolumetricexpansion.Largedeformationandcreepcanoccurinsoftrocks.Manysoftrocksarecompoundoneswhichhavecompositepropertiesformedfromtwoormoresetsofconstituentproperties.Softrockcanbegradedintodivisionsaccordingtoitsproperties.Afterengineeringhasoccurred,softrockcandeformrapidlyandbytime-dependentdeformation,owingtoitslowstrengthandsensitivitytothestressfield.Withtheeffectofwater,theexpansivemineralsinsoftrocksvolumetricallyexpand,whichcauseslargeconvergentdeformations,whichleadstodamageofthesurroundingrock.

Themechanicalpropertiesofsoftrocksappearsovariousanddifferentthatitisdifficulttoexpressthemwithmathematicalformula,whichisthetechnologicalchallengeforsoftrockengineering.

1.2.Engineeringinsoftrockanditsoptimization

Becausesoftrockengineeringcaninducelargedeformations,themaintenanceoftheengineeringcanbedifficult.Moreover,volumetricexpansionandlossofstabilizationofthesurroundingrockoftencausesdamagetosupportingstructures.Ifweusestrongsupportstocontrolthedeformationofthesurroundingrock,theengineeringcostwillbehigh,andtheconstructiontimewillbeincreasedbyrepeatedinstallationofsupport,sometimesthesupportitselfhastoberepaired.Inordertoobtainthebenefitsofeasierconstructionandlowercost,theintegraloptimizationofthesystemmustbecarriedoutandmanagedinasystematicandcomprehensiveway.

Designandconstructionarethetwoimportantstepsinsoftrockengineering.Thesemustbeginbyunderstandingthephysicalandmechanicalpropertiesofsoftrock,inthecontextofthestressfield,hydrogeologyandengineeringgeology.Theengineeringdesignplanisconceivedasawholeaccordingtothetheoryofrockmechanicsandcombiningpracticaldatafromadjacentorsimilarprojects,includingintegratingthemanyfactors.Theestablishmentofthecorrectsoftrockengineeringsystemshouldcomefrompractice,basingonafullmasteryofthefactors.TheschemeisshowninFig.1.

Fig.1.Engineeringsystemforsoftrock.

Optimizationofsoftrockengineeringisachievedbymakingthesurroundingrockinterfacewiththesupportingstructuresuchthattheengineeringwillbestable.Thekeytechnologicalstrategyistoavoidahighstressfieldandenhancethesupportingabilityofthesurroundingrock.Feasiblemeasuresareasfollows:

reducingtheexternalload;

optimizingtheengineeringstructure’ssizeandshape,improvingplanarandcubiclayoutsofengineering;

choosingbetterstrata,andstructureorientation,etc.,asshowninFig.2.

Fig.2.Theprincipleoftheoptimizationprocess.

Accordingtotheseideas,takethedevelopmentofacoalmineinsoftrockasanexample.Integratedoptimizationofthedevelopmentsystemofthemineshouldtaketherelevantfactorsintoaccount:

existinginformation;

anoverallarrangementforoptimaldevelopmentandproduction;

eliminateadversefactors;

anddealwiththeproblemsofsoftrockbyasimpleconstructionmethod.Thecontentofthefirstpartoftheoptimizationincludes:

choosingtheminedevelopmentmethod;

decidingonthemininglevel;

anddetermininglayersinwhichthemainroadwaysaretobelocated.Alsoimportantisarrangingareasonablelayoutofthepitbottomandchambergroupsandseekingtoreducethedeviatorstresscausedbymutualinterferenceoftheopenings.Openingsperpendiculartothedirectionofhorizontalprincipalstressshouldbeavoidedwhenchoosingthedrivingdirectionofroadways.Optimizingthelayoutoftheminingroadwaysreducesthedamagetosupportcausedbymovingloadsintroducedbymining.Furtheroptimizationisrelatedtothegeometryandsizeoftheroadwaysections,thesupportingstructure,andthemethodandtechnologyofconstruction.Finally,bymeasuringandmonitoringduringconstruction,feedbackinformationcanbeobtainedtoensurethattheengineeringisrunningontheexpectedtrackand,ifthereisanydeviation,correctiveactioncanbeimplemented.ThesystemisshowninFig.3.

Fig.3.Systematicoptimizationofcoalmininginsoftrock.

2.Engineeringexamples

2.1.MineNo.5inYoujiangcoalmine,China

ThemineissituatedtotheeastofBaiseCoalfield,intheWestofGuangxiZhuangAutonomousRegion.ItbelongstothenewthirdPeriod.Themineareaislocatedattheedgeofthesouthsynclinalbasin.Therearethreecoallayers;

theaveragethicknessofeachseamis1–2 

m;

aboveandbelowthecoallayersaremudstone,whosecoloursaregrey,greyishwhite,andgreen.Therearemineralsofmixedilliteandmontmorilloniteintherock,montmorillonite5–8%,andillite7–20%.Therock’suniaxialcompressivestrengthis4–5MPa,theaveragebeing4.8MPa.Thereareirregularjointsintherock,butdistributedirregularly,andtherock’sintegralcoefficientindexis0.55.Mostofthecracksarediscontinuous,withoutfillingmatterinthem.Thesurroundingrockisasoftrocksubjecttoswelling,withlowstrength,andisquitebroken.ThestrikeofthecoalfieldisNEE,thedipangleofthecoallayersis10–15°

.Themineareais6 

kmlongalongthestrike,and1 

kmlongalongitsinclination,itsareais6 

km2,therecoverablereservesare4,430,000tons.IntheadjacentmineNo.4,themaximumprincipalstressisNNE–SSW,approximatelyalongtheseams’inclineddirection.Aroadwayperpendiculartothisdirectionhasconvergencevaluesof70–100 

mm,thedamageofroadwaysupportsis51%.Aroadwayparalleltothedirectionofmaximumprincipalstresshasconvergencevaluesof20–40 

mm,thedamagerateofsupportsis12%,andtheaveragedamagerateofthemineis40%.

Inthedesignofthemine,apairofinclinedshaftswereincluded.Theleveloftheshaft-topis+110 

m,theelevationofthemainmininglevelislocatedat−120 

m.Strikelongwallminingisplanned,arrangingwithuphillanddownhillstopeareas,asshowninFig.4.

Fig.4.DevelopmentplansforMineNo.5inYoujiang.

Thefirstoptimizationmeasureistoweakenthestraineffectofthesurroundingrockinthemineroadwaycausedbythestressfield.Roadwaysarearrangedasfaraspossibletobeparallelwiththemaximumprincipalstress（thatis,approximatelyalongtheinclineddirection）soastoreducetheanglebetweenthem.Thestrikelongwallminingischangedintoinclinedlongwallmining,themineisminedupwardbyusingthedownhillstopearea,themainminingleveliselevatedby20 

m,1131 

mofroadwaysaresavedandthecostoftheroadwayconstructionandfacilitiesissaved¥

2,760,000（$336,600）.ThenewsystemisshowninFig.5.

Fig.5.DevelopmentsystemplansafteroptimizationforMineNo.5inYoujiang.

Thesecondoptimizationmeasureistochangethelayoutofthepitbottomandopeningstobeparallelwiththemaximumprincipalstressasfaraspossible.Thetotallengthofroadwaysinitiallydesignedwas1481 

m,and30.11%ofthemwerearrangedtobeperpendiculartothemaximumprincipalstress.Afteramendment,thetotallengthofroadwaysis1191 

m,whichisadecreaseof290 

m,andwithonly24.69%ofroadwaysthatareperpendiculartotheprincipalhorizontalstress,roadwaysareeasiertomaintain.AsshowninFig.6andFig.7.

Fig.6.LayoutofthepitbottomandchamberinitiallydesignedforMineNo.5inYoujiang.

Fig.7.Layoutofthepit