外文翻译--盾构机的压力调节液压推力系统的仿真分析 英文版.pdf

RESEARCHARTICLEZhibinLIU,HaiboXIE,HuayongYANGSimulationanalysisofpressureregulationofhydraulicthrustsystemonashieldtunnelingmachine©HigherEducationPressandSpringerVerlagBerlinHeidelberg2011AbstractHydraulicthrustsystemisanimportantsysteminashieldtunnelingmachine.Pressureregulationofthrustcylindersisthemostimportantfunctionforthrustsystemduringtunnelexcavation.Inthispaper,ahydraulicthrustsystemisexplained,andacorrespondingsimulationmodeliscarriedoutinordertostudythesystemcharacteristics.Pressureregulationofacertaingroupscylindershaslittleinfluenceonregulationoftheothergroupscylinders.Theinfluencewillnotaffecttheprocessmuchduringtunnelexcavation.Pumpdisplacementmayhaveagreatereffectonpressureregulationandoilsupplyflowrateshouldbeadaptivetothesystemsdemand.Aexactingsituationissimulatedtoexplainhowpressureregulationworksduringtunnelexcavation.Keywordstunnel,hydraulicthrustsystem,pressureregulation,simulation1IntroductionAshieldtunnelmachineisalargeandcomplexmachineusedinundergroundtunnelexcavation.Itisusedinconstructionprojectssuchasundergroundraillines,urbanpipelines,submarinetunnels,andsoon.Hydraulictechniqueiswidelyappliedinashieldtunnelingmachine.Forinstance,itisusedinthethrustsystem,thecutterheaddrivesystem,thescrewconveyor,andthesegmenterector.Researchworksabouttunnelexcavationhavebeencarriedout.SugimotoandSramoonbuiltatheoreticalmodelfortunnelexcavationbasedonmechanicsanalysis1theirsimulationresultsareingoodagreementwithobserveddata2.MaynarandRodriguezusedadiscretenumericalmodeltoanalyzetheexcavationprocess.Somestudiesaboutthrustforceandtorquewerealsocarriedout3.Xuetal.havediscoveredsomerelationshipbetweenworkingparametersduringtunnelexcavation4.Onlyafewstudiesaboutthehydraulicsystemonthemachinehavebeendone.Huetal.havedonesomeworkonathrustsystemofamachine.Pressureandflowcompoundcontrolhavealsobeenresearched5.AdifferentsysteminRef.5isstudiedinthisresearch.Pressureregulationofthrustsystemisstudiedbyusingasimplifiedsimulationmodelandcasesofsuchregulationarediscussed.2ThrustsystemAthrustsystemisanimportantpartofashieldtunnelingmachine.Thesystemconsistsofpowerunitselectricmotorandhydraulicpump,hydraulicvalves,andhydrauliccylindersasactuators.Thenumberofthrusthydrauliccylindersisusually16or32.Ifindividualcontrolofhydrauliccylindersisapplied,ahighnumberofproportionalcontrolvalvesandpressuresensorsarerequired.Moreover,themachineoperatorhastocontrol16or32pressureparametersduringexcavation.Individualcontrolisrathercomplicatedandexpensive.Nowadays,thrustcylindersareusuallydividedintofourorfivegroups,withthefourgrouparrangementmorecommon.FourgroupcylindersaredividedintoGroupA,GroupB,GroupC,andGroupD,correspondingtorightzone,lowerzone,leftzoneandupperzone.TheproportionofA∶B∶C∶Disusually4∶5∶4∶3,asshowninFig.1.MorecylindersarerequiredinGroupBsoastocountertheweightofcutterheadandthehigherearthpressureinthelowerzone.Oilpressuresindifferentcylindersarethesameiftheyareinthesamegroup.Inthiscase,onlyfourproportionalcontrolvalvesarerequired,andthemachineoperatoronlyhastocontrolfourpressureparameters.Duringtunnelexcavation,hydrauliccylindersaresuppliedwithhighpressurehydraulicoil,whichexertsonthesegmentstogenerateathrustforcetopushthemachineReceivedJanuary28,2011acceptedJune10,2011ZhibinLIU,HaiboXIE✉,HuayongYANGStateKeyLaboratoryofFluidPowerTransmissionandControl,ZhejiangUniversity,Hangzhou310027,ChinaEmailhbxiezju.edu.cnFront.Mech.Eng.2011,63377–382DOI10.1007/s114650110226yforward.Themachineoperatormayadjusthydraulicpressuresofthrustcylinderstoachievesteeringcontrolandmachinepostureadjustment.Afterathrustprocessisover,segmentswillbeinstalledtocomposeanewringoftunnel.Meanwhile,thrustcylindersareretractedinordertomakeroomforthosesegments.Whenasegmentislocated,correspondingcylindersareextendedout.Thesecylindersexertonthesegment,supportingthesegmentwithasmallforcetocompletetheinstallationprocess.3HydrauliccircuitandmodelingThehydrauliccircuitdiagramforthethrustsystemisshowninFig.2.Thesystemmainlyconsistsofavariabledisplacementpump1,apressurereliefvalve2,adirectionalcontrolvalve3,fourpressurereducingvalves4andsixteenhydrauliccylinders7.Pumpdisplacementisproportionaltotheinputsignal.Apressurereliefvalvekicksintoactionwhenthesystemisoverloaded,andadirectionalcontrolvalveisusedtocontroltheextensionmotionorretractionmotionofcylinders.Thepressurereducingvalveisthemostimportantcomponentandisusedtoadjustthehydraulicpressureofthecylinders.Whenthecylinderisextending,highpressureoilcomesfromhydraulicpump1,andthenflowsthroughdirectionalcontrolvalve3,pressurereducingvalve4,checkvalve5,on/offvalve6,finallyenteringtherearchamberofhydrauliccylinder7.Thebackpressureoilflowsoutoftherodchamberofcylinder7,thenthroughdirectionalcontrolvalve3andbackintotheoiltank.Whenthecylinderisretracting,oilflowsthroughdirectionalcontrolvalve3,thenintotherodchamberofhydrauliccylinder7.Thebackpressureoilflowoutoftherearchamber,thenthroughon/offvalve6,checkvalve8,directionalcontrolvalve3,andfinallyintotheoiltank.CommercialsoftwareAMESimisusedastheanalysistoolforthesimulation.Tosimplifythemodel,twogroupsofhydrauliccylinderstypicallyleftzoneandrightzoneareconsideredforanalysis.Byusingthesetwozones,itispossibletosimulatethesteeringmotionoftheshieldmachine.ThesimulationmodelisshownasFig.3.Allthehydraulicmodelsarethenormalmodelsprovidedbythesoftwareexceptforthepressurereducingvalves.Thevalveisbuiltasasupercomponentbycompositingseveralnormalmodels.Thevalvegivesmoredetailsaboutnotonlytheworkingparametersbutalsotheinternalstructures.Avariabledisplacementpumpisappliedasproportionaldisplacementcontrolpumpasithasthesamefunctionasthatonaworkingshieldmachine.Thepumpdisplacementisproportionaltotheinputsignal.Threekindsofforcesareconsideredinthecylinderloadmodelearthpressureforce,friction,andtheforcecausedbythethrustmotion.Earthpressureexertsonthecutterheadandliningsofthemachine.Thepressureforceexertedonthecutterheadaffectsthethrustmotion,andthepressureforceontheliningcanbeignored.Thefrictionforceonliningsofthemachinecausedbytheearthpressureisconsiderable,accountingforabouthalformoreofthethrustforce.Duringexcavation,however,thepressureforceandfrictionforcealmostmaintainconstantly.Thus,thesetwoforcesaresetasconstantinthemodel.Earthpressureissetbytheinputsignaloftheloadmodel,andfrictionissetinthemassmodelofcylinder.Thereisalinearrelationshipbetweenadvancingspeedandthrustforce,asshowninFig.44.Theblackstardotsrepresenttheexperimentalresultsfora68openratiocutterhead,andthewhitesquaredotsrepresenttheresultsfor36openratio.Eachsolidlineshowsthelinearrelationshipbetweenadvancingspeedandthrustforce.ThelinearrelationshiphasagoodagreementwiththeobserveddatainconstructionofLineNo.3intheGuangzhouMetro6.Fig.1Arrangementof4grouphydrauliccylindersFig.2Hydrauliccircuitofthrustsystem378Front.Mech.Eng.2011,63377–382Agreaterthrustforcecausesahigheradvancingspeed.Thatisbecausegreaterforceinducesagreaterfeedrateofcutters,andmoresoilwillbecutoffinafixedtimeinterval.Thethrustforceshouldbegreaterthanearthpressureexertedonthecutterheadtogetherwithfrictionforceonthelining,inordertopushthemachinetoadvance.Ifthrustforceisnotgreatenough,themachinewillnotadvance.InFig.3,thereisadeadbandintheloadmodel.ThedeadbandrepresentsthesituationinwhichthrustforceisnotgreatenoughtopushthemachineforwardsuchasituationisreferredtoinRef.6.Whilethemachineisadvancing,anincreaseofthethrustforcewillcauseanincreaseofadvancingspeed.Thisexperimentresultisappliedtotheloadmodel.Theorientationofmachineadvanceisinfluencedbythepressuredistributionofthrustcylinderssopressureregulationdeterminestheprocessionofexcavation.Themachineoperatormaycontrolthepostureofthemachinebyadjustingthepressuresofcylindergroups.Themachinemaysteerleftorright,oradvancealongasmallangleofslopeifcorrespondingsettingsofpressureregulationaregiven.Normally,attheendofatunnelexcavation,thedifferencebetweenactualtunnelaxisanddesignedtunnelaxisshouldbenomorethan20mm.Themachineoperatorwilladjustthemachineadvancingaxistoagreewiththedesignedaxis.Asaresult,pressureregulationisaveryimportantfunctionduringtunnelexcavation.4SimulationThesimulationparametersshowninTable1areobtainedfromashieldtunnelingmachineusedintheconstructionoftheNanjingMetro.Theleftandrightthrustgroupsareusedforsimulation,andsixteenhydrauliccylindersarereducedtoeight.A63cc/revmaximumdisplacementpumpshouldbereducedto31.5cc/rev.Pistondiameterofarealcylinderis300mm,androddiameteris240mm.Eithertheleftorrightthrustgroup,eachofwhichcontainsfourhydrauliccylinders,issimplifiedtoonehydrauliccylinder,whichhasthesameworkareaastheoriginalcylindergroup.Asaresult,thepistondiameterandroddiameterofsimulationcylinderare600and480mm,respectively.Whenoilpressureisabout8MPa,whichsuppliesabout9200kNofthrustforce,themachinebeginstomove.Reference7refersthatfrictionforceaccountsforabout53.5–73ofthrustforce.Accordingly,frictionforceissetat6000kN,about65ofthrustforce.Theremaining3200kNisexertedonthecutterheadfortunnelexcavation.4.1PressureregulationSteeringcontrolissimulatedinthiscase.Bothhydrauliccylindersareinitiallysettoabout14MPa.Themachineadvancesstraightandisexpectedtosteerleft.ThepressureofrightcylinderPrightshouldbehigherthanthatoftheleftPleft.Pleftmaymaintainat14MPa.Prightissetto20MPa.SimulationresultisshowninFigs.5and6.Prightisadjustedto20MPaasthestepsignalisgiven.ThereisasmallovershootofthepressureinFig.5asthereisamassspringsysteminthepilotstage.OvershootoftheFig.3SimulationmodelofthethrustsystemFig.4Thrustforceversusadvancingspeedinsoftground4Table1MainsimulationparametersItemSettingvaluePumpmaximumdisplacement30cc/revReliefpressure35.3MPaNominalpumpspeed1500revPistondiameterofcylinder600mmRoddiameterofcylinder480mmForceexertedoncutterhead3200kNFrictionforce6000kNZhibinLIUetal.Simulationanalysisofpressureregulationofhydraulicthrustsystem379massspringsystemcausesovershootoftheoutletpressureinthemainstage.PlefthasapulsewhenPrightisadjustedandincreasesslightlyafteradjustment.Thesuddenchangeininletpressurewillcausethesamepulseinoutletpressureatfirst.Becausethepilotstagefrequencyresponseisnothighenough,whenthepilotstagemechanismstartsadjustingthevalvesopeningarea,outletpressurewilldecreasetothesetvalue.ThesmallincreaseofPleftmightbecausedbytheincreaseofpumpoutletflowrate.Thepumpoutletflowratewillbediscussednext.Thissmalldifferenceinpressurewillnotaffectthetunnelexcavation.Higheradvancingspeedisachievedontherightside,asshowninFig.6.Aleftsteeringmotioniscarriedout.4.2PumpdisplacementadjustmentPumpdisplacementshouldbeadjustedwhenpressureregulationiscarriedout.Threecasesareilluminatedtoexplaintheproblem.Pressureregulationisoperatedasinthepreviouscase.Case1Displacementmaintainsatabout75ofmaximum.TheresultisshowninFig.7.Prightisadjustedto20MPa.Pressureregulationisachieved.However,pumpoutletpressureisat35.3MPa,whichmeansthesystemisoverloadedandthepressurereliefvalveopens.Powerlosscausedbyreliefflowisconsiderable.Case2Displacementmaintainsatabout50ofmaximum.TheresultisshowninFig.8.Pumpoutletpressureissensitivetotheloadpressure.Thereisnooverloadduringpressureregulation.However,thrustpressurecannotbeadjustedto20MPabecauseoilflowsupplyisnotenough.Higherthrustpressurecauseshigheradvancingspeed,whichmeansthecylinderrequiresmoreoilflowrate.Pressureregulationisinvalidatedinthiscase.Case3Displacementissetat50atfirst,then75whenpressureregulationiscarriedout.TheresultisshowninFig.9.Thereisnooverload.Pumpoutletpressureissensitivetotheloadpressure.Thrustpressurecanbeadjustedto20MPa.Thisisbecausepumpdisplacementisadaptivetothesystem.Apressureregulationshouldbetogetherwithapumpdisplacementregulation.4.3AtoughsituationInpractice,anoptimaltunnelprojectisworkedoutafterconsideringcommutersneeds,commercialdemand,geologicalconditions,andsoon.Shieldtunnelingmachineisexpectedtoadvanceingoodgeologicalconditions.Normally,ageologicalsurveyisdonebeforetheexcavationprocess.Itisimpossible,however,toknoweverythingFig.5PressuresofrightandleftcylindersduringpressureregulationofleftsteeringFig.6DisplacementsofrightandleftcylindersduringpressureregulationofleftsteeringFig.7Pressuresofpumpoutletandrightcylinderwhenpumpdisplacementmaintainsat75ofmaximumdisplacement380Front.Mech.Eng.2011,63377–382