完整版有关隧道方面外文文献与翻译Word格式.docx
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DepartmentofAppliedMathematics,
SouthChinaUniversityofTechnology,Guangzhou510640,China）
WUZiwang（吴紫汪）andZHULinnan（朱林楠）
（StatekeyLaboratoryofFrozenSoilEngineering,LanzhouInstituteofGlaciologyand
Geocryology
ChineseAcademyofSciences,Lanzhou730000,China）
ReceivedFebruary8,1999
Abstract
Basedontheanalysesoffundamentalmeteorologicalandhydrogeologicalconditionsatthesiteofatunnelinthecoldregions,acombinedconvection-conductionmodelforairflowinthetunnelandtemperaturefieldinthesurroundinghasbeenconstructed.Usingthemodel,theairtemperaturedistributionintheXiluoqiNo.2Tunnelhasbeensimulatednumerically.Thesimulatedresultsareinagreementwiththedataobserved.Then,basedontheinsituconditionsofsirtemperature,atmosphericpressure,windforce,hydrogeologyandengineeringgeology,theair-temperaturerelationshipbetweenthetemperatureonthesurfaceofthetunnelwallandtheairtemperatureattheentryandexitofthetunnelhasbeenobtained,andthefreeze-thawconditionsattheDabanshanTunnelwhichisnowunderconstructionispredicted.
Keywords:
tunnelincoldregions,convectiveheatexchangeandconduction,freeze-thaw.
AnumberofhighwayandrailwaytunnelshavebeenconstructedinthepermafrostregionsandtheirneighboringareasinChina.Sincethehydrologicalandthermalconditionschangedafteratunnelwasexcavated，thesurroundingwallrockmaterialsoftenfroze,thefrostheavingcauseddamagetothelinerlayersandseepingwaterfrozeintoicediamonds，whichseriouslyinterferedwiththecommunicationandtransportation.SimilarproblemsofthefreezingdamageinthetunnelsalsoappearedinothercountrieslikeRussia,NorwayandJapan.Henceitisurgenttopredictthefreeze-thawconditionsinthesurroundingrockmaterialsandprovideabasisforthedesign，constructionandmaintenanceofnewtunnelsincoldregions.
Manytunnels，constructedincoldregionsortheirneighbouringarea，spassthroughthepartbeneaththepermafrostbase.Afteratunnelisexcavat，edtheoriginalthermodynamicalconditionsinthesurroundingsareandthawdestroyedandreplacedmainlybytheairconnectionswithouttheheatradiation,theconditionsdeterminedprincipallybythetemperatureandvelocityofairflowinthetunnel，thecoefficientsofconvectiveheattransferonthetunnelwall，andthegeothermalheat.Inordertoanalyzeandpredictthefreezeandthawconditionsofthesurroundingwallrockofatunnel，presumingtheaxialvariationsofairflowtemperatureandthecoefficientsofconvectiveheattransfer,LunardinidiscussedthefreezeandthawconditionsbytheapproximateformulaeobtainedbySham-sundarinstudyoffreezingoutsideacirculartubewithaxialvariationsofcoolanttemperature.Wesimulatedthetemperatureconditionsonthesurfaceofatunnelwallvaryingsimilarlytotheperiodicchangesoftheoutsideairtemperature.Infact，thetemperaturesoftheairandthesurroundingwallrockmaterialaffecteachothersowecannotfindthetemperaturevariationsoftheairflowinadvance;
furthermore，itisdifficulttoquantifythecoefficientofconvectiveheatexchangeatthesurfaceofthetunnelwall.Thereforeitisnotpracticabletodefinethetemperatureonthesurfaceofthetunnelwallaccordingtotheoutsideairtemperature.Inthispaper,wecombinetheairflowconvectiveheatex-changeandheatconductioninthesurroundingrockmaterialintoonemode，landsimulatethefreeze-thawconditionsofthesurroundingrockmaterialbasedontheinsituconditionsofairtemperature，atmosphericpressure，windforceattheentryandexitofthetunnel，andtheconditionsofhydrogeologyandengineeringgeology.Mathematicalmodel
Inordertoconstructanappropriatemodel,weneedtheinsitufundamentalconditionsasaba-sis.HereweusetheconditionsatthesceneoftheDabanshanTunnel.TheDabanshanTunnelislo-totedonthehighwayfromXiningtoZhangye,southoftheDatongRiver,atanelevationof3754.78-3801.23m,withalengthof1530mandanalignmentfromsouthwesttonortheast.Thetunnelrunsfromthesouthwesttothenortheast.
Sincethemonthly-averageairtemperatureisbeneathO'
}Cforeightmonthsatthetunnelsiteeachyearandtheconstructionwouldlastforseveralyears，thesurroundingrockmaterialswouldbecomecoolerduringtheconstruction.Weconcludethat,afterexcavation,thepatternofairflowwoulddependmainlyonthedominantwindspeedattheentryandexit，andtheeffectsofthetemperaturedifferencebetweentheinsideandoutsideofthetunnelwouldbeverysmall.Sincethedominantwinddirectionisnortheastatthetunnelsiteinwinter,theairflowinthetunnelwouldgofromtheexittotheentry.Eventhoughthedominantwindtrendissoutheastlyinsummer,consideringthepressuredifference,thetemperaturedifferenceandthetopographyoftheentryandexi，ttheairflowinthetunnelwouldalsobefromtheexittoentry.Additionally，sincethewindspeedatthetunnelsiteislow，wecouldconsiderthattheairflowwouldbeprincipallylaminar.
Basedonthereasonsmentione，dwesimplifythetunneltoaroundtube，andconsiderthatthe
airflowandtemperaturearesymmetricalabouttheaxisofthetunnel，Ignoringtheinfluenceoftheairtemperatureonthespeedofairflow,weobtainthefollowingequation:
0<
x<
L,O<
r<
fij
ra（/vav亠
X+7★亦…
at/TI^u-z—+（/—+
dt%
wheret,x,rarethetime,axialandradialcoordinates;
U,Vareaxialandradialwindspeeds;
Tistemperature;
pistheeffectivepressure（that,isairpressuredividedbyairdensity）;
visthekinematicviscosityofair;
aisthethermalconductivityofair;
Listhelengthofthetunnel;
Ristheequivalentradiusofthetunnelsection;
Disthelengthoftimeafterthetunnelconstruction;
Sf（t）,Su（t）arefrozenandthawedpartsinthesurroundingrockmaterialsrespectively;
f,uandCf,Cuarethermalconductivitiesandvolumetricthermal
capacitiesinfrozenandthawedpartsrespectively;
X=（x,r）,（t）isphasechange
front;
Lhisheatlatentoffreezingwater;
andToiscriticalfreezingtemperatureofrock（hereweassumeTo=-0.1C）.
2usedforsolvingthemodel
Equation
（1）showsflow.Wefirstsolvethoseconcerningtemperatureatthatthetemperatureofthesurroundingrockdoesnotaffectthespeedofairequationsconcerningthespeedofairflow,andthensolvethoseequationseverytimeelapse.2.1Procedureusedforsolvingthecontinuityandmomentumequations
Sincethefirstthreeequationsin
（1）arenotindependentwederivethesecond
equationbyx
andthethirdequationbyr.Afterpreliminarycalculationweobtainthefollowing
ellipticequationconcerningtheeffectivepressurep:
「艺p,丄空仃肚、J裂工r3r\dr）~t卄升
10<
A
3Uav\2VZ
nJ"
Q・
（2）
»
0<
R.
Thenwesolveequationsin
（1）usingthefollowingprocedures:
（i）AssumethevaluesforU0V0;
（ii）substitutingU0,V0intoeq.
（2）,andsolving
（2）,weobtainp0;
（iii）solvingthefirstandsecondequationsof
（1）,weobtainU0,V1;
（iv）solvingthefirstandthirdequationsof
（1）,weobtainU2,V2;
（v）calculatingthemomentum-averageofU1,v1andU2,v2,weobtainthenew
U0,V0;
thenreturnto（ii）;
（vi）iteratingasaboveuntilthedisparityofthosesolutionsintwoconsecutiveiterationsissufficientlysmallorissatisfied,wethentakethosevaluesofp0U0and
V0astheinitialvaluesforthenextelapseandsolvethoseequationsconcerningthetemperature..
2.2Entiremethodusedforsolvingtheenergyequations
Asmentionedpreviously,thetemperaturefieldofthesurroundingrockandtheairflowaffecteachother.Thusthesurfaceofthetunnelwallisboththeboundaryofthetemperaturefieldinthesurroundingrockandtheboundaryofthetemperaturefieldinairflow.Therefore,itisdifficulttoseparatelyidentifythetemperatureonthetunnelwallsurface,andwecannotindependentlysolvethoseequationsconcerningthetemperatureofairflowandthoseequationsconcerningthetemperatureofthesurroundingrock.Inordertocopewiththisproblem,wesimultaneouslysolvethetwogroupsofequationsbasedonthefactthatatthetunnelwallsurfacebothtemperaturesareequal.Weshouldbearinmindthephasechangewhilesolvingthoseequationsconcerningthetemperatureofthesurroundingrockandtheconvectionwhilesolvingthoseequationsconcerningthetemperatureoftheairflow,andweonlyneedtosmooththoserelativeparametersatthetunnelwallsurface.Thesolvingmethodsfor
theequationswiththephasechangearethesameasinreferenee[3].
2.3Determinationofthermalparametersandinitialandboundaryconditions2.3.1Determinationofthethermalparameters.Usingp=1013.25-0.1088H,wecalculate
PairpressurepatelevationHandcalculatetheairdensityusingformula,
whereTistheyearly-averageabsoluteairtemperatureandGisthehumidityconstantofair.LettingCPbethethermalcapacitywithfixedpressure,thethermalconductivity,andthedynamicviscosityofairflow,wecalculatethethermalconductivityandofthesurroundingrockaredeterminedfromthetunnelsite.
2.3.2Determinationoftheinitialandboundaryconditions.Choosetheobservedmonthlyaveragewindspeedattheentryandexitasboundaryconditionsofwindspeed
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