隧道施工技术台阶开挖法课件

隧道施工技术台阶开挖法TunnelConstructionTechnologyBenchExcavationMethod台阶开挖法目录BenchExcavationMethodTableofContents台阶开挖法的基本概念1长台阶法2短台阶法3超短台阶法45课程小结SettingandApplicableConditionsofCanopyTubeSelectionofSupportParametersforCanopyTubeConstructionProcessofCanopyTubeQualityStandardsandInspectionMethodsofCanopyTubeSummary台阶开挖法的基本概念01BasicConceptofBenchExcavationMethod台阶开挖法台阶开挖法的基本概念BenchExcavationMethodBasicConceptofBenchExcavationMethod

台阶开挖法，简称“台阶法”

，是将设计断面分上半断面和下半断面两次开挖成型。Benchexcavationmethod,alsoknownas“benchcutmethod”,istodividethedesignsectionintoanupperhalfsectionandalowerhalfsection,whichareexcavatedandformedintwotimes.台阶开挖法台阶开挖法的基本概念BenchExcavationMethodBasicConceptofBenchExcavationMethod

台阶开挖法，简称“台阶法”

，是将设计断面分上半断面和下半断面两次开挖成型。Benchexcavationmethod,alsoknownas“benchcutmethod”,istodividethedesignsectionintoanupperhalfsectionandalowerhalfsection,whichareexcavatedandformedintwotimes.台阶开挖法台阶开挖法的基本概念BenchExcavationMethodBasicConceptofBenchExcavationMethod

台阶开挖法，简称“台阶法”

，是将设计断面分上半断面和下半断面两次开挖成型。Benchexcavationmethod,alsoknownas“benchcutmethod”,istodividethedesignsectionintoanupperhalfsectionandalowerhalfsection,whichareexcavatedandformedintwotimes.台阶法

BenchCutMethod台阶长度

Benchlength长台阶法

LongBenchCutMethod短台阶法

ShortBenchCutMethod超短台阶法

Ultra-shortBenchCutMethod台阶开挖法台阶法的分类BenchExcavationMethodClassificationofthestepmethod长台阶法02LongBenchCutMethod长台阶法的定义DefinitionofLongBenchCutMethod台阶开挖法长台阶法BenchExcavationMethodLongBenchCutMethod上、下断面相距较远，一般上台阶超前50m以上或大于5倍洞跨。Theupperbenchisgenerallymorethan50maheadormorethan5timesthetunnelspanastheupperandlowersectionsarefarapart.台阶开挖法长台阶法的施工要点BenchExcavationMethodKeyPointsofConstructionwithLongBenchCutMethod根据支护结构形成闭合断面的时间要求，必要时在开挖上半断面后，可修筑临时底拱，形成上半断面的临时闭合结构，然后在开挖下半断面时再将临时底拱挖掉。上半断面UpperhalfsectionAccordingtothetimerequirementsforthesupportstructuretoformaclosedsection,atemporarybottomarchmaybeconstructedwhennecessaryafterexcavationoftheupperhalfsection,formingatemporaryclosurestructureoftheupperhalfsection,andthenthetemporarybottomarchcanberemovedwhenthelowerhalfsectionisexcavated.上半断面Upperhalfsection台阶开挖法长台阶法的施工要点BenchExcavationMethodKeyPointsofConstructionwithLongBenchCutMethod但从经济观点来看，最好不这样做，而改用短台阶法。However,fromaneconomicpointofview,itisbettertoadopttheshortbenchcutmethod.台阶开挖法长台阶法的施工要点BenchExcavationMethodKeyPointsofConstructionwithLongBenchCutMethod下半断面Lowerhalfsection需要注意炮眼的布置方式Attentionshallbepaidtothelayoutofblastholes

①平行隧道轴线的水平眼。Thefirstisthehorizontalholeparalleltothetunnelaxis.这种方式的炮眼主要布置在设计断面轮廓线上，能有效地控制开挖断面。Theblastholesinthiswayaremainlyarrangedonthecontourlineofthedesignsectiontoeffectivelycontroltheexcavationsection.需要注意炮眼的布置方式Attentionshallbepaidtothelayoutofblastholes台阶开挖法长台阶法的施工要点BenchExcavationMethodKeyPointsofConstructionwithLongBenchCutMethod下半断面Lowerhalfsection

②由上台阶向下钻进的竖直眼又称插眼。Thesecondistheverticalholedrilleddownwardfromtheupperbench,alsoknownastheinsertionhole.这种方式的增破效果较好，但爆破时石渣飞出较远，容易打坏机械设备。Thismethodmaybetterimprovetheblastingeffect,butrockballastsflywayduringblasting,whichiseasytodamagemechanicalequipment.台阶开挖法长台阶法的施工要点BenchExcavationMethodKeyPointsofConstructionwithLongBenchCutMethod下半断面Lowerhalfsection待初期支护的变形稳定后，或根据施工组织所规定的日期附设防水层(必要时)和建造内层衬砌。注意Notesafterthedeformationoftheprimarysupportisstable,orsetwaterprooflayer(whennecessary)andbuildinnerliningaccordingtothedatespecifiedbytheconstructionorganization.台阶开挖法长台阶法的特点BenchExcavationMethodCharacteristicsofLongBenchCutMethod特点Features1

长台阶法有足够的工作空间和相当快的施工速度，上部开挖支护后，下部作业就较为安全，但上下部作业有一定的干扰；Intermsoflongbenchcutmethod,withenoughworkingspaceandgoodconstructionspeed,thelowerpartissaferaftertheupperpartisexcavatedandsupported,butthereisacertaininterferencebetweentheupperandloweroperations.台阶开挖法长台阶法的特点BenchExcavationMethodCharacteristicsofLongBenchCutMethod2长台阶法一次开挖的断面和高度都比较小，只需配备中型钻孔台车即可施工，而且，对维持开挖面的稳定也十分有利；Boththesectionandheightofone-timeexcavationwithlongbenchcutmethodaresmall,therefore,themedium-sizeddrillingjumbocanbeadoptedforconstruction,whichisalsobeneficialtomaintainthestabilityofexcavationface.台阶开挖法长台阶法的特点BenchExcavationMethodCharacteristicsofLongBenchCutMethod3适用范围较广，凡是在全断面法中开挖面不能自稳，但围岩坚硬不需用底拱封闭断面的情况，都可采用长台阶法。Sothelongbenchcutmethodhasawiderangeofapplication.Inallcaseswheretheexcavationfacecannotbeself-stabilizedinthefullfacemethod,whilethesurroundingrockishardandthesectionisnotclosedbybottomarch,thelongbenchcutmethodcanbeadopted.台阶开挖法长台阶法的特点BenchExcavationMethodCharacteristicsofLongBenchCutMethod短台阶法03ShortBenchCutMethod台阶长度小于5倍但大于1至1.5倍洞跨，或是台阶长度在5至50m范围内，为短台阶。台阶开挖法短台阶法BenchExcavationMethodShortBenchCutMethod短台阶法的定义DefinitionofShortBenchCutMethodThebenchlengthislessthan5timesbutgreaterthan1~1.5timesthetunnelspan,orthebenchlengthiswithin5-50m.Advancingdirection短台阶法的作业顺序和长台阶法相同Theconstructionsequenceoftheshortbenchcutmethodisthesameasthatofthelongbenchcutmethod.台阶开挖法短台阶法的特点及适用条件BenchExcavationMethodCharacteristicsofShortBenchCutMethodandShortBenchCutMethod短台阶法的特点CharacteristicsofShortBenchCutMethod可缩短支护结构闭合的时间，改善初次支护的受力条件，有利于控制隧道的收敛速度和量值。优点Advantages短台阶法的ofShortBenchCutMethodShorteningtheclosuretimeofthesupportstructure,improvingthestressconditionsoftheprimarysupport,helpingcontroltheconvergencespeedandmagnitudeofthetunnel.上台阶出渣时对下半断面施工的干扰较大，不能全部平行作业。缺点Disadvantages短台阶法的ofShortBenchCutMethodTheconstructionofthelowerhalfsectionisgreatlydisturbedbythemuckingfromtheupperbench,andparallelconstructionisunavailable.台阶开挖法短台阶法的特点及适用条件BenchExcavationMethodCharacteristicsofShortBenchCutMethodandShortBenchCutMethod

短台阶法的适用范围较广，I~V级围岩都能采用，尤其适用于IV、V级围岩，是经常采用的一种方法。短台阶法的适用条件ApplicableConditionsofShortBenchCutMethodTherefore,shortbenchcutmethodiswidelyapplicabletoClassI~Vsurroundingrocks,especiallyClassIVandVsurroundingrocks.Itisafrequentlyusedmethod.台阶开挖法短台阶法的特点及适用条件BenchExcavationMethodCharacteristicsofShortBenchCutMethodandShortBenchCutMethod采用短台阶法时应注意的问题PrecautionsforShortBenchCutMethod1初期支护全断面闭合要在距开挖面30m以内，或距开挖上半断面开始的30d内完成；Thefullfaceoftheprimarysupportshallbeclosedwithin30mfromtheexcavationface,orcompletedwithin30dfromthebeginningofexcavationoftheupperhalfsection.2当初期支护变形、下沉显著时，要提前闭合；Whenthedeformationandsubsidenceoftheprimarysupportaresignificant,advanceclosureisrequired.3要确定在保证施工机械正常工作前提下的台阶最小长度。Theminimumlengthofbenchshallbedeterminedonthepremiseofensuringthenormaloperationofconstructionmachinery.超短台阶法04Ultra-shortBenchCutMethod台阶开挖法超短台阶法BenchExcavationMethodUltra-shortBenchCutMethod上台阶仅超前3～5m，只能采用交替作业。Theupperbenchisonly3-5mahead,andonlyalternateoperationcanbeadopted.超短台阶法的定义DefinitionofUltra-shortBenchCutMethodAdvancingdirection台阶开挖法超短台阶法BenchExcavationMethodUltra-shortBenchCutMethod超短台阶法施工的作业顺序OperationSequenceofUltra-shortBenchCutMethod◆用一台停在台阶下的长臂挖掘机或单臂掘进机开挖半断面至一个进尺；Usealong-armexcavatororasingle-armTBMparkedatthebenchfoottoexcavatetheupperhalfsectiontoonefootage.◆安设拱部锚杆钢筋网或钢支撑，喷拱部混凝土；Installarchanchorrod,reinforcingmeshorsteelsupport,andsprayarchconcrete.◆用同一台机械开挖下半断面至一个进尺，安设边墙锚杆、钢筋网或接长钢支撑，喷边墙混

凝土(必要时加喷拱部混凝土)；Usethesamemachinetoexcavatethelowerhalfsectiontoonefootage,installsidewallanchorrod,reinforcingmeshorextendsteelsupport,andspraysidewallconcrete.◆开挖水沟，安设底部钢支撑，喷底拱混凝土，灌注内层衬砌。Excavateditch,installbottomsteelsupport,spraybottomarchconcreteandpourinnerlining.台阶开挖法超短台阶法的特点及适用条件BenchExcavationMethodCharacteristicsofShortBenchCutMethodandShortBenchCutMethod超短台阶法的特点CharacteristicsofUltra-shortBenchCutMethod超短台阶法的初期支护全断面闭合时间更短，更有利于控制围岩变形，能在城市隧道施工中更有效地控制地表沉陷。优点Advantages超短台阶法的ofUltra-shortBenchCutMethodRelativelyshorterfullfaceclosingtimeofprimarysupport.moreconducivetocontrollingthedeformationofsurroundingrock,availabletocontrolthesurfacesubsidenceduringurbantunnelconstructionmoreeffectively.上、下断面相距较近，机械设备集中,作业时相互干扰较大，生产效率较低，施工速度较慢。缺点Disadvantages超短台阶法的ofUltra-shortBenchCutMethodCloserdistancebetweenupperandlowersections,centralizedmechanicalequipment,greatmutualinterferenceduringoperation,lowproductionefficiency,slowconstructionspeed.膨胀性围岩和土质围岩中要求及早闭合断面的场合，以及机械化程度不高的各类围岩地段。超短台阶法的适用条件ApplicableConditionsofUltra-shortBenchCutMethodTheoccasionswhereearlyclosureofsectionsisrequiredinexpansiveandsoilsurroundingrocks,andvarioussurroundingrocksectionswithlowdegreeofmechanization.台阶开挖法超短台阶法的特点及适用条件BenchExcavationMethodCharacteristicsofShortBenchCutMethodandShortBenchCutMethod在软弱围岩中施工时，应特别注意开挖工作面的稳定性，必要时可采取辅助施工措施，如向围岩中注浆或打入超前水平小钢管，对开挖面进行预加固或预支护。超短台阶法施工时应注意的问题PrecautionsforConstructionwithUltra-shortBenchCutMethodForconstructioninweaksurroundingrock,specialattentionshallbepaidtothestabilityofexcavationworkingface,andauxiliaryconstructionmeasurescanbetakenwhennecessary.Forexample,groutordriveadvancedhorizontalsmallsteelpipeintothesurroundingrock,pre-reinforceorpre-supporttheexcavationface.台阶开挖法超短台阶法的特点及适用条件BenchExcavationMethodCharacteristicsofShortBenchCutMethodandShortBenchCutMethod台阶开挖法台阶开挖法BenchExcavationMethod台阶法的施工要点KeyPointsofConstructionwithBenchCutMethod

下半断面的开挖(又称落底)应在上半断面初期支护基本稳定后进行，或采取其他有效措施确保初期支护体系的稳定性；采用单侧落底或双侧交错落底，避免上部初期支护两侧同时悬空；视围岩状况严格控制落底长度，一般采用1~3m，并不得大于6m。

Theexcavationofthelowerhalfsection(alsoknownasbottoming)shallbecarriedoutaftertheprimarysupportoftheupperhalfsectionisbasicallystable,ortakeothereffectivemeasurestoensurethestabilityoftheprimarysupportsystem;Adoptone-sidedbottomingortwo-sidedstaggeredbottomingtoavoidsimultaneoussuspensiononbothsidesoftheupperprimarysupport;thebottominglengthshallbestrictlycontrolledaccordingtothesurroundingrockconditions,whichisgenerally1-3mandshallnotbegreaterthan6m.下部边墙开挖后必须立即喷射混凝土，并按规定做初期支护。

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