隧道工程洞身開(kāi)挖作業(yè)指導(dǎo)書(shū)中英文

TUNNELEXCAVATIONI.SCOPETheworksofthissectionincludeexcavatingoftunnelbody,carriagegallery,pedestriangallery,auxiliarygalleryandtherelatedworkssuchasshaftconstruction,drillingandblasting,tunnelsupporting,excavatedmaterialloadingandhaulingetc..II.GENERALREQUIREMENTS1.TheContractorshallsubmitconstructionprogram(includingexcavationsequences,explosion,constructionlighting,ventilation,drainage,support,ballastremoval,lining,etc.)thatismostsuitabletotheactualconditionsofthetunnel,accordingtosuchconditionsasgeology,mechanicalequipmenttotheEngineerforreviewandapproval28daysbeforeexcavation.TheNewAustrianTunnelingMethodisadvisabletobeapplied.TimelychangemaybealsomadefortheconstructionmethodbasedontheactualconditionsandmustbeapprovedbytheEngineertomatchwithchangesofspecificconditions.2.TheContractorshalladoptmodernizationconstructiontechniqueandreasonablyarrangeprocedures,organizescientificallyconstructionaccordingtotheapprovedconstructionprogramtoensurequalifiedprojectqualityandreasonableschedule.3.TheContractorshallarrangecorrectlymeasurementsduringconstructiontoensurethatthetunnelisconstructedaccordingtodesigndirectionandslopegradientandexcavatedsectionconformstodimensionsshownontheDrawing.Excavateddimensionsaredonecorrectly.Benchmarkislocatedateach50minsidetunnel.4.TheContractorshallnotberelievedofhisresponsibilityindefectsorfailureoftunnelworksduetotheconstructionmethodapprovedbytheEngineer.5.Duringconstruction,accordingtothedirectobservationtocuttingface,themseasurementtodeformationofthesurroundingrock,withassistantofadvancedgeologicalpredictionandsupplementofstrataformation,lithologicalcharactersandgroundwater,theContractorshallraisehismodificationopinionforclassificationofsurroundingrock,judgestabilityofthesurroundingrockaroundthegallery,putforwardcorrespondingtreatmentandsubmittotheEngineerforapproval.III.EXCAVATIONOPERATION1.ExcavationRequirements(1)TheContractorshall,inaccordancewiththeapprovedconstructionmethodsorthesucceedingapprovedmodificationplans,completetheexcavationoperation.Beforethecompletionoftheprotectionworkofsideslopeatthetunnelopening,thetunnelbodyexcavationshallnotbestarted.(2)TheContractorshalladopttheexcavationmethodthatreducesdisturbanceonthesurroundingrockintunnelbodyinordertoutilizetheself-supportingcharacteristicsofthesurroundingrocktothemaximumlimitation.Formethodsofexcavationofdifferentsurroundingrock,stipulationsinTechnicalSpecificationsforConstructionofHighwayTunnel(JTJ042-94)shallbereferredto.(3)Duringexcavationoftunnelbody,allcrosssectiondimensionsshallconformtotherequirementsontheDrawings.Sideditch,cabletrenchandfoundationofsidewallshallbeexcavatedsimultaneously.AlltheexcavationshallbecarriedoutaccordingtotheexcavationlineshownontheDrawings,andshallbecompletedinoneexcavation.Inthecourseofexcavation,theContractorshallfromtimetotimesurveythepositionoftunnelaxisandelevation.Beforeconstructionoftunnelschambersforprovision,theyshallbecheckedagainsttheDrawingstoensurethequantityandaccuratepositionofthem.(4)Duringexcavation,theContractorshallusemethods,whicharebeneficialtothereductionofover-excavationandthestabilityofthesurroundingrock.ThecostofallmaterialsandconstructionfortheoverreachbeyondtheallowedrangemadebytheContractorforwhatevercauseincludingbackfillofover-excavationaretheContractor'sliability.(5)Under-excavationshallnotoccurinexcavationoftunnelexceptwhenrockstratumisperfectwithcompressivestrengthmorethan30MPa,andtheEngineerconfirmsthattheunder-excavationwillnotaffectthestructuralstabilityandstrengthofthelinings,inthiscase,individualpartofarock(notgreaterthan0.1m2persquaremeter)mayintrudeintotheliningwithin50mm.Under-excavationonthecrosssectionlessthanlmabovefootingsofthearchandthewallisstrictlyforbidden.(6)Whenusingbenchcutmethodintunnelconstruction,thebenchispreferablenottobedividedintotoomanysteps,thedistanceoflowerpartandtheupperpartofthebenchshallsatisfyasfaraspossiblethenormaloperationrequirementsofthemachines/videdthetopsurroundingrocksarebrokenandfollowingupsupportisrequired,thebenchmaybeproperlylengthened.(7)Whentheworkingfacesofoppositesidesarenearlyexcavatedthrough,theconstructionofbothsidesshallcontactwitheachothertightly.Whenthedistanceoftwoworkingfacesremains15m,thetunnelshallbeexcavatedthroughfromoneside.(8)Inexcavationofshallowburiedtunnel,itshouldbecarryouttodecreasethefootagetopreventcollapse,whichshallbenefittodiminishthesettlementofgroundsurface.So,accordingtoactualconditions,thepropermeasuresaretakenasfollow:a.Singlearmtunnelingmachineorpneumaticpickisusedsoastodecreasethedisturbanceofsurroundingrockinconstruction.Theprincipleofshortfootage,strongsupport,weakblasting,regularobservationandsurveyingshallbeobservedforblastingexcavation;b.Strengthenthetreatmentofspringing,andsetanchorbarofspringing;c.Constructinvertedarchortemporaryinvertedarchintime;d.Makedeepholerockgroutingforthesurroundingrock2~3maroundtheperipheryoftunnelwhendeformationoftheprimarysupportistoolargeandreinforcementisnotappropriate..e.WhenconstructinginweakandbrokensurroundingrockofClassⅣorClassⅤ,orthereiswateremerginginthetunnel,suchmeasuresshallbeadoptedaspre-grouting,orsettingstratumanchorbarfromthegroundsurface,orringconsolidationgroutinginthetunnelorstrengtheningthestratumbyusingpipe-shed.f.Observationandfeedbackofsettlementofgroundsurfaceandsettlementofarchcrownshallbestrengthenedsoastoinstructconstruction.(9)UltimatedeviationoftwoconstructionalcenterlinesinoppositedirectionsonthethroughfaceoftunnelshallconformtostipulationsinTable-1Table-lUltimateThroughErrorofTunnelCenterlineKindsLengthbetwween2oppposiiteeexcavvateddtunnnelfronnts((m)UltimattedeeviattionontthetthrouughffaceofcttaereohwnoulmTransveersall<3000±1503000～60000±200>6000±300ElevatiionNolimiit±70(10)Whenthebenchmarkoftunnelportalislocatedoutsidetunnel,measurementdeviationandrootmeansquaredeviationonthethroughfacecausedbylayingoutrouteshallconformtostipulationsinTable-2.Table-2RootMeanSquareErrorontheThroughFaceMeasureementtloccatioonLengthbetwween2oppposiiteeexcavvateddtunnnelfronnts((m)Meansqquareedevviatiionoofheeightt(mm))＜30003000～60000＞6000Rootmeeanssquarredeeviattionontthetthrouughfface((mm)Outsideetunnnel45609025Insidetunnnel608012025Alltunnnel7510015035(11)Forsoftandweakbrokenrockattunnelopeningsection,usualmeasuresaretakentostabilizeexcavatedworkfaceasfollows:providedcorepartduringcircularexcavation;excavationoperationsurfacesealedbyshotcrete;advanceanchorboltoradvancetubule;pipe-shed;Advancetubulegrouting;temporarilyinvertedarchsubseal,pre-castegroutingofexcavationoperationsurfaceandsurroundingrocketc.ConstructioniscarriedoutaccordingtorequirementsofDrawing,ifunspecified,themeasuresshallbeselectedaccordingtogeologiccondition,groundwaterstateandconstructionmethodduringconstruction,thisshouldbesubmittedtotheEngineerforapproval.(12)Whensoftandweaksurroundingrockattunnelopeningisexcavatedusingbenchcutmethodintunnelconstruction,thedistanceoflowerpartandtheupperpartofthebenchshallbelessthan30m;whentunnelopeningsectionislocatedinthebulkcongeries,excavationisdoneusingmicro-benchingtunnelingmethodandcircularcutprovidedcorepartsoilmethod,thedistanceoflowerpartandtheupperpartofthebenchshallbelessthan5m;invertedarchandarchsteelframeshallsealedtimely,invertedarchconcreteshallbegroutedintimetoavoidexcessivesettlementandintrudingintodesignlimitedrange.2.BlastingDesign(1)Intheblastingexcavationinrocktunnel,keyfactorsofblasttechnology,suchasthesizeanddepthofdrill-hole,theintervalbetweenholes,thequantityofdynamite,thedistributionofdrill-hole,andthesequenceofblasting,shallbestudiescarefullyandstrictlycontrolled.Atleast14dayspriortoblastingconstructionoperation,theContractorshallcompletethedesignofdrillingandblasting,andsubmitittotheEngineerforapproval.(2)Thedesignshallbecarriedoutbasedonthecomprehensivestudyofgeologicalconditions,excavatedsection,methodofexcavation,excavationcyclefootage,machines/toolsofdrilling,blastingmaterials,etc.Themaincontentsare:layoutofblastholes(includingholecuttingtype,drillingdepthandobliquity);structuraldiagramofdynamitefilling(includingamountofdynamiteandblastholestemmingmethod);parametertableofdrillingandblasting;blastingmethodandsequence,blastingdiagram(shallbedrawnifnecessary),andmaintechnicalandeconomicindicesandnecessarydescriptions.(3)Smoothblastingorpre-splittingblastingshallbeusedindrillingandblastingdesign.Blastingparametersshallbeselectedanddeterminedthroughtests.Iftestconditionsarenotavailable,relevantparameterinTechnicalSpecificationsforConstructionofHighwayTunnel(JTJ042-94)maybereferred.a.Technicalrequirementsforsmoothblasting:(a)Residualtracesofblastholesshallbeevenlydistributedontheexcavationcontoursurface.Retainingrateofblastholetrace:notlessthan80%forhardrock,notlessthan70%formedianhardrock,notlessthan50%forsoftrock.(b)Rocksurfacebetweentwoneighboringholesshallbeflatandeven,noevidentblastfissuresareallowedontheholewall.(c)Benchtypedeviationthatappearsbetweentwoneighboringholesshallnotbegreaterthan150mm.(d)Thebiasederrorofboreholeshallnotexceed1°.b.Requirementstothepre-splittingblast(a)Priortoignitingthemainblasthole,instantaneousblastinsingle-rowandcloserimholemaybeusedtoobtainthepre-splittingSurfacealongexcavationcontourlinewhichshallreducethedamageofouterlayerofrockresultingfromthemainblasthole.(b)Themostidealconditionisthatasinglebreaklineshallconnectnearbyblastholeonebyone,andhalfblastingtraceoftherimholesectionismaintainedinsurroundingrockafterblasting.(c)Thepre-splittingseamwidthofthepre-splittingblastholeisadvisabletobenotlessthan5mmingeneral.(d)Thebiasederrorofboreholeshallnotexceed1°.3.DrillingandBlastingOperation(1)Drillingandblastoperationshallbecarriedoutaccordingtoitsdesign.Whentheexcavationconditionchanges,correspondingchangesofblastingtechnologyshallbemadeaccordingtothevariationoftheconditionofsurroundingrock.(2)Priortodrillingholes,thecenterlineandthelevelofexcavatedsection,theoutlineofthesectionshallbedrawnandthelocationofblastholesshallbemarkedinaccordancewiththeblastdesign.Whenitconformstothedesignrequirementsthroughchecking,thedrillingofholesmaybestarted.(3)Depth,angleandintervalofblastholesshallbedeterminedinaccordancewithdesignrequirementsandshallconfirmtotherequirementsofdesignaccuracy.(4)Whenallholeshavebeendrilled,checkshallbecarriedoutinaccordancewiththearrangementdrawingoftheblastholes,andrecordsshallbetaken.Whenqualificationisprovedthroughinspection,dynamitefillingmaybestarted.(5)Mud,accumulatedwater,androckpowderinblastholesshallbeblownoutandwashedclearlypriortofillingthedynamite.Allblastholesshallbeblockeduptimelywithstemming.Theblockedlengthofrimholesshallnotbelessthan200mm.Whenthepre-splittingblastmethodisused,blockingupshallbemadefromthetopofdynamitepackagebutnotfromthemouthoftheholesonly.(6)Whenelectricityisadoptedforignition,theoperationshallbecarriedoutaccordingtostipulationsinConstructionandAcceptanceSpecificationforEarthworkandBlastWork(GBJ201-1983)andTechnicalSpecificationsforConstructionofHighwayTunnel(JTJ042-94).(7)Rimholesareavailabletobedetonatedatthesametime.Theymaybedetonatedingroupsaccordingtothegeologicalcondition,andblastshockinghastobecontrolledwhenoperatedinsoftrocksection.Ortherimholesaredensifiedtodetonatedinsmalldiameterholeandlessexplosive.(8)Afterblasting,exclusivepersonshallbeassignedtoclearthetopandthesurrounding,meanwhileinspectingtheworkingfaceandun-liningsectionshallbecarriedout.Ifitisdiscoveredthatdangermayoccur,theContractorshalltakemeasuresintimeforeliminating.(9)TheexcavationandblastingforcontinuousarchtunnelshallcarrystrictlyouttheprincipleofShortFootage,WeakBlastingandoperationrequirementsofBlastingandVibration.Excavationandblastingofnucleusrockinworkfaceshouldn’taffectandevendamageconstructionsafetyoflinedstructures.4.OperationinThunderingandLightningPeriod(1)Whenthunderandlightningareapproaching,allthegroundorundergroundtransportofdynamitesandshortdistancehaulingshallbesuspendedimmediately;allpersonnelshallbeevacuatedtothesafeplaces.Theworkingpersonnelinsidethetunnelshallbeinformedofthecomingandpassingoverofthethunderandlightingbysignals.(2)Insectionswheretheblastworkhasbeenfinished,theContractorshallprovide,installanduseapprovedthunderandlightningmonitorapparatusandautomaticalarmdevices.5.BlastingandVibration(l)Thegroundvibrationcausedbyblastingorotheroperationsarenotallowedtodamageexistingbuildingandpublicfacilities.(2)TheContractorshallprovidequalifiedinstruments,andassignmeasuringpersonnelanddocumentanalysispersonnel,monitorandrecordeveryvibrationsituationofblastingandsituationofair-pressureboost,adjusttheblastingoperationtomakethevibrationnotexceedallowablevaluetopreventexcavationinstability.(3)Allblastingandconstructionoperationsshallguaranteethemaximumvelocityofvibrationtoexistingbuildingnotexceed25mm/s.Fornewcastconcrete,thevibrationvelocityallowedshallnotexceedthestipulatedvaluesinTable-3:Table-3TheVibrationVelocityLimitedValueofNewCastConcreteAgeofConccretee(h))LimitoofViibrattionVeloocityy(mmm/s)12～246.2524～4812.548～12025(4)Theblastshockassociatednoisemeasuredintheexistingbuildingneartheblastpointshallnotexceed130dB.Inrecordingthesituationofblastwithmaximumshockrecorderbywirefrequencyreaction,theextra-pressureofairmustnotexceed0.005Mpa.AlltheinstrumentsandequipmentrelatedtothemonitoringshallbeprovidedbytheContractorandusedaccordingtotherelevantrequirements.(5)Blastingisbestrictlyforbiddeninthenon-blastingarearegulatedintheContractDrawings.TherelateddataofvibrationrecordshallbesubmittedatanyTimetotheEnginneerforinspection,andduplicatedcopyshallbeprovidedwhennecessary.6.SafetyMeasuresofBlasting(l)Variousworkslikemanaging,processing,transporting,inspectinganddestroyingofblastingmaterials,shallconformtorelevantstipulationsinSafetyRegulationsforBlasting(GB6722-2003).(2)Theoriginalrecordsforreceivingandusingofblastingmaterialsshallbewelldoneandwellfiled.(3)Duringblasting,allpersonnelshallwithdrawtoareasoutsidetheeffectiverange,wherenormallyshallbefarawayfortheblastingsitewithadistancenotlessthan200m.Inperiodofblasting,besideselectriccircuitsforignition,allotherpowerorlightcircuitsshallbeswitchedofformovetoplacesnotlessthan50mawayfromtheblastingpoint.(4)Iftheexcavationworkandliningworkaretobetakingplaceinparallel,adistance,whichisusuallynotlessthan30m,shallbekeptaccordingtothestrengthofconcrete,surroundingrockcharacterandthescaleofblasting.(5)Ingastunnel,electricfiring,permissibleexplosiveandmilliseconddetonatormustbeadopted,whilefuseandexposedcartridgeareprohibited.(6)Beforechargingandblastingingastunnel,safetyinspectionmustbedonetoensurethegasdensitylessthan1%.(7)Afterblasting,theConstructorsshallnotallowedpersonneltoentertheblastingareauntilthesmokeisblownoverbyfreshair,airintheworkfaceischeckedtobequalifiedandallpersonnelshallwaitmorethan15min.7.SafetyMeasuresforHarmfulGas(l)Ifharmfulgasisexistedinthetunnel,allthepersonnelshallstopworkimmediatelyandwithdrawtotheoutsideoftunnel.TheContractorshalltaketreatmentmeasures,operationmaynotbecontinuedinthetunneluntilitisconfirmedthattherearenolongeranydanger.(2)TheContractorshallmakeregularlyinspectionandrecordoftheharmfulgaswithautomaticdetectionandrecordinginstrument/equipmentprovided.TherecordingdatashallbesubmittedtotheEngineerforchecking.HarmfulgasinthetunnelmustnotexceedthestandardprescribedinSub-clause507.03-1(2).(3)Forconstructionintunnelswithharmfulgas,alarmandanalyticalinstrumentforcontinuousmonitoringofcombustiblegasandharmfulgasshallbeinstalled.Thealarmisabletovisuallyalarmandalsoauditoryalarm.(4)TheContractorshallprovidehispersonnelwithvariousnecessarysafetytoolsorinstrument,safetylamp,gasmaskandoxygensupplyingequipmentintheareawhereharmfulgasispossibletoappear.洞身開(kāi)挖一、范圍本節(jié)工作內(nèi)容包括洞身及車行橫通道、人行橫通道、輔助坑道的開(kāi)挖以及豎井、鉆孔爆破、施工支護(hù)、裝渣運(yùn)輸?shù)扔嘘P(guān)作業(yè)。二、一般規(guī)定1.承包人應(yīng)在開(kāi)挖前28d根據(jù)地質(zhì)、機(jī)械設(shè)備等條件向監(jiān)理工程師提出符合隧道具體情況的施工方案（包括開(kāi)挖順序、爆破、施工照明、通風(fēng)、排水、支護(hù)、出渣等），并經(jīng)監(jiān)理工程師審查批準(zhǔn)。施工方法采用新奧法；根據(jù)施工中具體情況的變化，也可及時(shí)改變施工方法，但都必須報(bào)經(jīng)監(jiān)理工程師批準(zhǔn)。2.承包人應(yīng)根據(jù)批準(zhǔn)的施工方案，采用現(xiàn)代化施工技術(shù)，合理地安排工序，科學(xué)地組織隧道施工，以保證合格的施工質(zhì)量和合理的計(jì)劃進(jìn)度。3.承包人應(yīng)安排好施工過(guò)程的測(cè)量，以保證隧道按設(shè)計(jì)方向和坡度施工，使開(kāi)挖斷面符合圖紙所示尺寸，盡量做到不欠挖和不超挖。洞內(nèi)還應(yīng)每隔50m設(shè)置一個(gè)水準(zhǔn)點(diǎn)。4.監(jiān)理工程師批準(zhǔn)的施工方法，如有導(dǎo)致工程缺陷或失敗的情況，都不應(yīng)減輕承包人在施工中的責(zé)任。5.在施工過(guò)程中，承包人應(yīng)根據(jù)對(duì)開(kāi)挖面的直接觀察、圍巖變形的量測(cè)結(jié)果。輔以超前地質(zhì)預(yù)報(bào)，結(jié)合巖層構(gòu)造、巖性及地下水情況，提出圍巖分級(jí)的修改意見(jiàn)，并判定坑道圍巖的穩(wěn)定性，提出相應(yīng)的處理措施，報(bào)請(qǐng)工程師批準(zhǔn)。三、開(kāi)挖作業(yè)1.開(kāi)挖要求（1）承包人應(yīng)根據(jù)監(jiān)理工程師批準(zhǔn)的施工方案或其后批準(zhǔn)的修改方案完成開(kāi)挖作業(yè)。洞口處邊坡防護(hù)工程未完成前，不得進(jìn)行洞身開(kāi)挖。（2）為了最大限度地利用圍巖自承能力，承包人必須采用減少圍巖擾動(dòng)的方法進(jìn)行洞身開(kāi)挖。各類圍巖的開(kāi)挖方法按設(shè)計(jì)并符合《公路隧道施工技術(shù)規(guī)范》（JTJ042－94）的有關(guān)規(guī)定。（3）洞身開(kāi)挖斷面尺寸應(yīng)符合圖紙要求，邊溝、電纜溝及邊墻基礎(chǔ)也同時(shí)開(kāi)挖，所有開(kāi)挖應(yīng)按圖紙標(biāo)明的開(kāi)挖線進(jìn)行施工，并一次挖夠。在開(kāi)挖過(guò)程中，承包人應(yīng)隨時(shí)測(cè)定隧道軸線位置和標(biāo)高。預(yù)留洞室在施工前應(yīng)與圖紙進(jìn)行核對(duì)，確保洞室的數(shù)量與位置正確。（4）在開(kāi)挖的進(jìn)程中應(yīng)考慮按有利于減少超挖、有利于圍巖的穩(wěn)定的施工方法進(jìn)行。無(wú)論承包人出于何種原因所造成的超過(guò)允許范圍的超挖以及這部分超挖的回填，所有材料和施工費(fèi)用均由承包人負(fù)責(zé)。（5）嚴(yán)格控制斷面開(kāi)挖，不應(yīng)欠挖，僅在巖層完整、抗壓強(qiáng)度大于30MPa，經(jīng)監(jiān)理工程師確認(rèn)不影響襯砌結(jié)構(gòu)的穩(wěn)定和強(qiáng)度時(shí)，巖石個(gè)別突出部分（每平方米內(nèi)不大于0.1m2）可侵入襯砌，侵入量不大于50mm。拱腳、墻腳以上1m內(nèi)斷面嚴(yán)禁欠挖。（6）采用臺(tái)階法施工時(shí)，臺(tái)階不宜分層過(guò)多，上下臺(tái)階之間的距離盡可能滿足機(jī)具正常作業(yè)，并減少翻渣工作量；當(dāng)頂部圍巖破碎，需支護(hù)緊跟時(shí)，可適當(dāng)延長(zhǎng)臺(tái)階長(zhǎng)度。（7）當(dāng)兩相對(duì)掘進(jìn)工作面接近打通時(shí)，兩端施工應(yīng)加強(qiáng)聯(lián)系，統(tǒng)一指揮。當(dāng)兩工作面的距離剩下15m時(shí)，應(yīng)從一面掘進(jìn)貫通。（8）淺埋隧道開(kāi)挖時(shí)應(yīng)嚴(yán)格控制地表沉陷，減小循環(huán)開(kāi)挖進(jìn)尺和防止塌方。為此，應(yīng)根據(jù)具體情況，采取適當(dāng)措施，如：a.施工中為減少對(duì)圍巖擾動(dòng)，宜采用單臂掘進(jìn)機(jī)或風(fēng)鎬開(kāi)挖，爆破開(kāi)挖時(shí)應(yīng)遵循短進(jìn)尺、強(qiáng)支護(hù)、弱爆破、勤觀測(cè)的原則；b.應(yīng)加強(qiáng)對(duì)拱腳的處理，安設(shè)拱腳錨桿；c.及時(shí)施作仰拱或臨時(shí)仰拱；d.若初期支護(hù)變形過(guò)大，又不宜加固時(shí)，可對(duì)洞周2～3m范圍內(nèi)的圍巖進(jìn)行系統(tǒng)深孔巖石注漿；e.在V級(jí)或VI級(jí)軟弱破碎圍巖中施工或洞中有涌水時(shí)，應(yīng)采用預(yù)注漿，或從地表安設(shè)地層錨桿，或洞內(nèi)環(huán)形固結(jié)注漿或采用管棚法加固地層；f.應(yīng)加強(qiáng)地表下沉、拱頂下沉的觀測(cè)及反饋，以指導(dǎo)施工。（9）隧道內(nèi)兩相向施工中線在貫通面上的極限誤差應(yīng)符合表－1的規(guī)定。由于貫通誤差引起增加的工程量均不再另予計(jì)量和支付。隧道中線極限貫通誤差表－1類別兩相向開(kāi)挖洞口口間長(zhǎng)度（m）兩端施工中線在在貫通面上上的極限誤誤差(mmm)橫向<3000±1503000～60000±200>6000±300高程不限±70（10）由洞外設(shè)置洞口基點(diǎn)樁時(shí)，測(cè)量誤差和洞內(nèi)支導(dǎo)線放樣測(cè)量誤差引起的貫通面產(chǎn)生的中誤差應(yīng)不大于表-2的規(guī)定。貫通通中誤差表-2測(cè)量部位兩開(kāi)挖洞口間長(zhǎng)長(zhǎng)度（m）高程中誤差（mmm）＜30003000～60000＞6000貫通中誤差（mmm）洞外45609025洞內(nèi)608012025全部隧道7510015035（11）對(duì)洞口段段軟弱破碎碎巖層，穩(wěn)穩(wěn)定開(kāi)挖工工作面的常常用措施有有：環(huán)形開(kāi)開(kāi)挖留核心心；用噴射射混凝土封封閉開(kāi)挖工工作面；超超前錨桿或或超前小鋼鋼管；管棚棚；超前小小導(dǎo)管注漿漿；臨時(shí)仰仰拱封底；；開(kāi)挖工作作面及圍巖巖預(yù)注漿等等。施工時(shí)時(shí)應(yīng)按圖紙紙規(guī)定進(jìn)行行，如無(wú)規(guī)規(guī)定，施工工時(shí)視地質(zhì)質(zhì)條件、地地下水狀況況、施工方方法等進(jìn)行行選擇，報(bào)報(bào)請(qǐng)監(jiān)理工工程師批準(zhǔn)準(zhǔn)。（12）隧道洞口口軟弱圍巖巖段采用臺(tái)臺(tái)階法開(kāi)挖挖時(shí)，上下下臺(tái)階之間間的距離不不能大于330m，當(dāng)當(dāng)洞口段位位于松散堆堆積體內(nèi)時(shí)時(shí)，應(yīng)采用用微臺(tái)階法法或環(huán)形開(kāi)開(kāi)挖預(yù)留核核心土法開(kāi)開(kāi)挖，上下下臺(tái)階之間間的距離不不能大于55m，仰拱拱和拱部鋼鋼架應(yīng)及時(shí)時(shí)全封閉，仰仰拱砼應(yīng)及時(shí)澆澆筑，以避避免沉降過(guò)過(guò)大而侵入入設(shè)計(jì)限界界。2.鉆爆設(shè)計(jì)計(jì)（1）在巖石隧道爆爆破作業(yè)的的掘進(jìn)中，對(duì)對(duì)爆破技術(shù)術(shù)諸要素如如鉆眼大小小、孔深、間間距、藥量量、鉆眼分分布與起爆爆順序等應(yīng)應(yīng)慎重研究究與嚴(yán)格控控制。在進(jìn)行鉆爆施工工前至少144d，承包包人應(yīng)完成成鉆爆設(shè)計(jì)計(jì)并報(bào)請(qǐng)監(jiān)監(jiān)理工程師師批準(zhǔn)。（2）鉆爆設(shè)計(jì)應(yīng)在在綜合研究究地質(zhì)條件件、開(kāi)挖斷斷面、開(kāi)挖挖方法、掘掘進(jìn)循環(huán)進(jìn)進(jìn)尺、鉆眼眼機(jī)具、爆爆破器材等等的基礎(chǔ)上上進(jìn)行。其其主要內(nèi)容容有：炮孔孔布置圖（包包括掏槽方方式、鉆孔孔深度及斜斜度）；裝裝藥結(jié)構(gòu)圖圖（包括裝裝藥量及炮炮孔堵塞方方式）；鉆鉆爆參數(shù)表表；起爆方方法和順序序，必要時(shí)時(shí)應(yīng)繪制爆爆破圖；主主要技術(shù)經(jīng)經(jīng)濟(jì)指標(biāo)及及必要的說(shuō)說(shuō)明。（3）鉆爆設(shè)計(jì)應(yīng)使使用光面爆爆破或預(yù)裂裂爆破技術(shù)術(shù)。爆破參參數(shù)的選擇擇，均應(yīng)通通過(guò)試驗(yàn)確確定；無(wú)試試驗(yàn)條件時(shí)時(shí),可參照《公公路隧道施施工技術(shù)規(guī)規(guī)范》(JJTJ0042－94）中的的有關(guān)參數(shù)數(shù)。a.光面爆破的的要求（a）殘留炮孔痕跡跡，應(yīng)在開(kāi)開(kāi)挖輪廓面面上均勻分分布。炮孔孔痕跡保留留率：硬巖巖不少于880％，中中硬巖不少少于70％，軟軟巖不少于于50％。（b）相鄰兩孔之間間的巖面平平整，孔壁壁不應(yīng)有明明顯的爆破破裂隙。（c）相