隧道施工技術臺階開挖法TunnelConstructionTechnologyBenchExcavationMethod臺階開挖法目錄BenchExcavationMethodTableofContents臺階開挖法的基本概念1長臺階法2短臺階法3超短臺階法45課程小結SettingandApplicableConditionsofCanopyTubeSelectionofSupportParametersforCanopyTubeConstructionProcessofCanopyTubeQualityStandardsandInspectionMethodsofCanopyTubeSummary臺階開挖法的基本概念01BasicConceptofBenchExcavationMethod臺階開挖法臺階開挖法的基本概念BenchExcavationMethodBasicConceptofBenchExcavationMethod

臺階開挖法，簡稱“臺階法”

，是將設計斷面分上半斷面和下半斷面兩次開挖成型。Benchexcavationmethod,alsoknownas“benchcutmethod”,istodividethedesignsectionintoanupperhalfsectionandalowerhalfsection,whichareexcavatedandformedintwotimes.臺階開挖法臺階開挖法的基本概念BenchExcavationMethodBasicConceptofBenchExcavationMethod

臺階開挖法，簡稱“臺階法”

，是將設計斷面分上半斷面和下半斷面兩次開挖成型。Benchexcavationmethod,alsoknownas“benchcutmethod”,istodividethedesignsectionintoanupperhalfsectionandalowerhalfsection,whichareexcavatedandformedintwotimes.臺階開挖法臺階開挖法的基本概念BenchExcavationMethodBasicConceptofBenchExcavationMethod

臺階開挖法，簡稱“臺階法”

，是將設計斷面分上半斷面和下半斷面兩次開挖成型。Benchexcavationmethod,alsoknownas“benchcutmethod”,istodividethedesignsectionintoanupperhalfsectionandalowerhalfsection,whichareexcavatedandformedintwotimes.臺階法

BenchCutMethod臺階長度

Benchlength長臺階法

LongBenchCutMethod短臺階法

ShortBenchCutMethod超短臺階法

Ultra-shortBenchCutMethod臺階開挖法臺階法的分類BenchExcavationMethodClassificationofthestepmethod長臺階法02LongBenchCutMethod長臺階法的定義DefinitionofLongBenchCutMethod臺階開挖法長臺階法BenchExcavationMethodLongBenchCutMethod上、下斷面相距較遠，一般上臺階超前50m以上或大于5倍洞跨。Theupperbenchisgenerallymorethan50maheadormorethan5timesthetunnelspanastheupperandlowersectionsarefarapart.臺階開挖法長臺階法的施工要點BenchExcavationMethodKeyPointsofConstructionwithLongBenchCutMethod根據支護結構形成閉合斷面的時間要求，必要時在開挖上半斷面后，可修筑臨時底拱，形成上半斷面的臨時閉合結構，然后在開挖下半斷面時再將臨時底拱挖掉。上半斷面UpperhalfsectionAccordingtothetimerequirementsforthesupportstructuretoformaclosedsection,atemporarybottomarchmaybeconstructedwhennecessaryafterexcavationoftheupperhalfsection,formingatemporaryclosurestructureoftheupperhalfsection,andthenthetemporarybottomarchcanberemovedwhenthelowerhalfsectionisexcavated.上半斷面Upperhalfsection臺階開挖法長臺階法的施工要點BenchExcavationMethodKeyPointsofConstructionwithLongBenchCutMethod但從經濟觀點來看，最好不這樣做，而改用短臺階法。However,fromaneconomicpointofview,itisbettertoadopttheshortbenchcutmethod.臺階開挖法長臺階法的施工要點BenchExcavationMethodKeyPointsofConstructionwithLongBenchCutMethod下半斷面Lowerhalfsection需要注意炮眼的布置方式Attentionshallbepaidtothelayoutofblastholes

①平行隧道軸線的水平眼。Thefirstisthehorizontalholeparalleltothetunnelaxis.這種方式的炮眼主要布置在設計斷面輪廓線上，能有效地控制開挖斷面。Theblastholesinthiswayaremainlyarrangedonthecontourlineofthedesignsectiontoeffectivelycontroltheexcavationsection.需要注意炮眼的布置方式Attentionshallbepaidtothelayoutofblastholes臺階開挖法長臺階法的施工要點BenchExcavationMethodKeyPointsofConstructionwithLongBenchCutMethod下半斷面Lowerhalfsection

②由上臺階向下鉆進的豎直眼又稱插眼。Thesecondistheverticalholedrilleddownwardfromtheupperbench,alsoknownastheinsertionhole.這種方式的增破效果較好，但爆破時石渣飛出較遠，容易打壞機械設備。Thismethodmaybetterimprovetheblastingeffect,butrockballastsflywayduringblasting,whichiseasytodamagemechanicalequipment.臺階開挖法長臺階法的施工要點BenchExcavationMethodKeyPointsofConstructionwithLongBenchCutMethod下半斷面Lowerhalfsection待初期支護的變形穩定后，或根據施工組織所規定的日期附設防水層(必要時)和建造內層襯砌。注意Notesafterthedeformationoftheprimarysupportisstable,orsetwaterprooflayer(whennecessary)andbuildinnerliningaccordingtothedatespecifiedbytheconstructionorganization.臺階開挖法長臺階法的特點BenchExcavationMethodCharacteristicsofLongBenchCutMethod特點Features1

長臺階法有足夠的工作空間和相當快的施工速度，上部開挖支護后，下部作業就較為安全，但上下部作業有一定的干擾；Intermsoflongbenchcutmethod,withenoughworkingspaceandgoodconstructionspeed,thelowerpartissaferaftertheupperpartisexcavatedandsupported,butthereisacertaininterferencebetweentheupperandloweroperations.臺階開挖法長臺階法的特點BenchExcavationMethodCharacteristicsofLongBenchCutMethod2長臺階法一次開挖的斷面和高度都比較小，只需配備中型鉆孔臺車即可施工，而且，對維持開挖面的穩定也十分有利；Boththesectionandheightofone-timeexcavationwithlongbenchcutmethodaresmall,therefore,themedium-sizeddrillingjumbocanbeadoptedforconstruction,whichisalsobeneficialtomaintainthestabilityofexcavationface.臺階開挖法長臺階法的特點BenchExcavationMethodCharacteristicsofLongBenchCutMethod3適用范圍較廣，凡是在全斷面法中開挖面不能自穩，但圍巖堅硬不需用底拱封閉斷面的情況，都可采用長臺階法。Sothelongbenchcutmethodhasawiderangeofapplication.Inallcaseswheretheexcavationfacecannotbeself-stabilizedinthefullfacemethod,whilethesurroundingrockishardandthesectionisnotclosedbybottomarch,thelongbenchcutmethodcanbeadopted.臺階開挖法長臺階法的特點BenchExcavationMethodCharacteristicsofLongBenchCutMethod短臺階法03ShortBenchCutMethod臺階長度小于5倍但大于1至1.5倍洞跨，或是臺階長度在5至50m范圍內，為短臺階。臺階開挖法短臺階法BenchExcavationMethodShortBenchCutMethod短臺階法的定義DefinitionofShortBenchCutMethodThebenchlengthislessthan5timesbutgreaterthan1~1.5timesthetunnelspan,orthebenchlengthiswithin5-50m.Advancingdirection短臺階法的作業順序和長臺階法相同Theconstructionsequenceoftheshortbenchcutmethodisthesameasthatofthelongbenchcutmethod.臺階開挖法短臺階法的特點及適用條件BenchExcavationMethodCharacteristicsofShortBenchCutMethodandShortBenchCutMethod短臺階法的特點CharacteristicsofShortBenchCutMethod可縮短支護結構閉合的時間，改善初次支護的受力條件，有利于控制隧道的收斂速度和量值。優點Advantages短臺階法的ofShortBenchCutMethodShorteningtheclosuretimeofthesupportstructure,improvingthestressconditionsoftheprimarysupport,helpingcontroltheconvergencespeedandmagnitudeofthetunnel.上臺階出渣時對下半斷面施工的干擾較大，不能全部平行作業。缺點Disadvantages短臺階法的ofShortBenchCutMethodTheconstructionofthelowerhalfsectionisgreatlydisturbedbythemuckingfromtheupperbench,andparallelconstructionisunavailable.臺階開挖法短臺階法的特點及適用條件BenchExcavationMethodCharacteristicsofShortBenchCutMethodandShortBenchCutMethod

短臺階法的適用范圍較廣，I~V級圍巖都能采用，尤其適用于IV、V級圍巖，是經常采用的一種方法。短臺階法的適用條件ApplicableConditionsofShortBenchCutMethodTherefore,shortbenchcutmethodiswidelyapplicabletoClassI~Vsurroundingrocks,especiallyClassIVandVsurroundingrocks.Itisafrequentlyusedmethod.臺階開挖法短臺階法的特點及適用條件BenchExcavationMethodCharacteristicsofShortBenchCutMethodandShortBenchCutMethod采用短臺階法時應注意的問題PrecautionsforShortBenchCutMethod1初期支護全斷面閉合要在距開挖面30m以內，或距開挖上半斷面開始的30d內完成；Thefullfaceoftheprimarysupportshallbeclosedwithin30mfromtheexcavationface,orcompletedwithin30dfromthebeginningofexcavationoftheupperhalfsection.2當初期支護變形、下沉顯著時，要提前閉合；Whenthedeformationandsubsidenceoftheprimarysupportaresignificant,advanceclosureisrequired.3要確定在保證施工機械正常工作前提下的臺階最小長度。Theminimumlengthofbenchshallbedeterminedonthepremiseofensuringthenormaloperationofconstructionmachinery.超短臺階法04Ultra-shortBenchCutMethod臺階開挖法超短臺階法BenchExcavationMethodUltra-shortBenchCutMethod上臺階僅超前3～5m，只能采用交替作業。Theupperbenchisonly3-5mahead,andonlyalternateoperationcanbeadopted.超短臺階法的定義DefinitionofUltra-shortBenchCutMethodAdvancingdirection臺階開挖法超短臺階法BenchExcavationMethodUltra-shortBenchCutMethod超短臺階法施工的作業順序OperationSequenceofUltra-shortBenchCutMethod◆用一臺停在臺階下的長臂挖掘機或單臂掘進機開挖半斷面至一個進尺；Usealong-armexcavatororasingle-armTBMparkedatthebenchfoottoexcavatetheupperhalfsectiontoonefootage.◆安設拱部錨桿鋼筋網或鋼支撐，噴拱部混凝土；Installarchanchorrod,reinforcingmeshorsteelsupport,andsprayarchconcrete.◆用同一臺機械開挖下半斷面至一個進尺，安設邊墻錨桿、鋼筋網或接長鋼支撐，噴邊墻混

凝土(必要時加噴拱部混凝土)；Usethesamemachinetoexcavatethelowerhalfsectiontoonefootage,installsidewallanchorrod,reinforcingmeshorextendsteelsupport,andspraysidewallconcrete.◆開挖水溝，安設底部鋼支撐，噴底拱混凝土，灌注內層襯砌。Excavateditch,installbottomsteelsupport,spraybottomarchconcreteandpourinnerlining.臺階開挖法超短臺階法的特點及適用條件BenchExcavationMethodCharacteristicsofShortBenchCutMethodandShortBenchCutMethod超短臺階法的特點CharacteristicsofUltra-shortBenchCutMethod超短臺階法的初期支護全斷面閉合時間更短，更有利于控制圍巖變形，能在城市隧道施工中更有效地控制地表沉陷。優點Advantages超短臺階法的ofUltra-shortBenchCutMethodRelativelyshorterfullfaceclosingtimeofprimarysupport.moreconducivetocontrollingthedeformationofsurroundingrock,availabletocontrolthesurfacesubsidenceduringurbantunnelconstructionmoreeffectively.上、下斷面相距較近，機械設備集中,作業時相互干擾較大，生產效率較低，施工速度較慢。缺點Disadvantages超短臺階法的ofUltra-shortBenchCutMethodCloserdistancebetweenupperandlowersections,centralizedmechanicalequipment,greatmutualinterferenceduringoperation,lowproductionefficiency,slowconstructionspeed.膨脹性圍巖和土質圍巖中要求及早閉合斷面的場合，以及機械化程度不高的各類圍巖地段。超短臺階法的適用條件ApplicableConditionsofUltra-shortBenchCutMethodTheoccasionswhereearlyclosureofsectionsisrequiredinexpansiveandsoilsurroundingrocks,andvarioussurroundingrocksectionswithlowdegreeofmechanization.臺階開挖法超短臺階法的特點及適用條件BenchExcavationMethodCharacteristicsofShortBenchCutMethodandShortBenchCutMethod在軟弱圍巖中施工時，應特別注意開挖工作面的穩定性，必要時可采取輔助施工措施，如向圍巖中注漿或打入超前水平小鋼管，對開挖面進行預加固或預支護。超短臺階法施工時應注意的問題PrecautionsforConstructionwithUltra-shortBenchCutMethodForconstructioninweaksurroundingrock,specialattentionshallbepaidtothestabilityofexcavationworkingface,andauxiliaryconstructionmeasurescanbetakenwhennecessary.Forexample,groutordriveadvancedhorizontalsmallsteelpipeintothesurroundingrock,pre-reinforceorpre-supporttheexcavationface.臺階開挖法超短臺階法的特點及適用條件BenchExcavationMethodCharacteristicsofShortBenchCutMethodandShortBenchCutMethod臺階開挖法臺階開挖法BenchExcavationMethod臺階法的施工要點KeyPointsofConstructionwithBenchCutMethod

下半斷面的開挖(又稱落底)應在上半斷面初期支護基本穩定后進行，或采取其他有效措施確保初期支護體系的穩定性；采用單側落底或雙側交錯落底，避免上部初期支護兩側同時懸空；視圍巖狀況嚴格控制落底長度，一般采用1~3m，并不得大于6m。

Theexcavationofthelowerhalfsection(alsoknownasbottoming)shallbecarriedoutaftertheprimarysupportoftheupperhalfsectionisbasicallystable,ortakeothereffectivemeasurestoensurethestabilityoftheprimarysupportsystem;Adoptone-sidedbottomingortwo-sidedstaggeredbottomingtoavoidsimultaneoussuspensiononbothsidesoftheupperprimarysupport;thebottominglengthshallbestrictlycontrolledaccordingtothesurroundingrockconditions,whichisgenerally1-3mandshallnotbegreaterthan6m.下部邊墻開挖后必須立即噴射混凝土，并按規定做初期支護。

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