隧道施工項(xiàng)目六支護(hù)施工38課件

Tunnelconstruction

隧道施工

項(xiàng)目六支護(hù)施工Project6Supportconstruction任務(wù)一初期支護(hù)Initialsupport——噴射混凝土施工Shotcreteconstruction學(xué)習(xí)目標(biāo)Learningobjectives2知識(shí)目標(biāo)Knowledgeobjectives能力目標(biāo)Competencyobjectives通過本任務(wù)的學(xué)習(xí)，學(xué)生應(yīng)掌握噴射混凝土的施工工藝流程；掌握噴射混凝土施工過程中的質(zhì)量控制要點(diǎn)；Throughthestudyofthistask,studentsshouldmastertheconstructionprocessofshotcrete;Masterthekeypointsofqualitycontrolintheconstructionprocessofshotcrete;通過本任務(wù)的學(xué)習(xí)，學(xué)生應(yīng)能初步具備噴射混凝土工程施工及質(zhì)量控制能力、編制噴射混凝土作業(yè)技術(shù)交底的能力。Throughthestudyofthistask,studentsshouldbeabletoinitiallyhavetheabilityofsprayedconcreteengineeringconstructionandqualitycontrol,andtheabilitytoprepareshotcreteworktechnology.二、噴射混凝土Shotcrete噴射混凝土的施工Constructionofshotcrete1.施工準(zhǔn)備Constructionpreparation（1）工、料、機(jī)的準(zhǔn)備：人工、材料、機(jī)械（具）的準(zhǔn)備，核實(shí)品種、質(zhì)量要求、足夠儲(chǔ)備量。噴射機(jī)械的就位，并試運(yùn)轉(zhuǎn)。(1)Preparationofwork,materialsandmachines:preparationoflabor,materials,machinery(equipment),verificationofvarieties,qualityrequirements,andsufficientreserves.Thejettingmachineryisinplaceandcommissioned.（2）濕噴場(chǎng)地的準(zhǔn)備：檢查隧道開挖斷面的凈空尺寸；沖洗受噴巖面；作噴射混凝土的厚度的標(biāo)志；施工平面的布置，應(yīng)滿足施工工藝的要求；布置應(yīng)力求緊湊，充分利用場(chǎng)地空間及運(yùn)輸線，避免施工干擾。Preparationofwetspraysites:checktheclearancedimensionsofthetunnelexcavationsection;Flushingofthesprayedrocksurface;Asasignofthethicknessofshotcrete;Thelayoutoftheconstructionplaneshouldmeettherequirementsoftheconstructionprocess;Thelayoutshouldbecompact,makefulluseofthesitespaceandtransportationlines,andavoidconstructioninterference.二、噴射混凝土Shotcrete噴射混凝土的施工Constructionofshotcrete2.施噴作業(yè)Sprayingoperations（1）噴嘴與受噴巖面之間的距離和角度(1)Thedistanceandanglebetweenthenozzleandthesurfaceofthesprayedrock噴嘴與受噴巖面之間的最優(yōu)距離是按噴混凝土的最高強(qiáng)度和最小回彈量來確定的，一般以0.6～1.8m為宜。角度：垂直噴射向受噴面，困難部位傾斜不大于10°。Theoptimaldistancebetweenthenozzleandthesurfaceofthesprayedrockisdeterminedbythemaximumstrengthandminimumreboundofthesprayedconcrete,anditisgenerallyappropriateto.8m0.6to1.Angle:Verticalspraytothesprayedsurface,thedifficultpartistiltednotmorethan10°.（2）厚度和間隔時(shí)間Thicknessandintervaltime根據(jù)噴射效率、回彈損失等因素確定，拱部一次噴射厚度6~10cm，側(cè)壁為8~10cm。Accordingtotheinjectionefficiency,reboundlossandotherfactors,thearchis6to10cmthickatatime,andthesidewallis8to10cm.間隔時(shí)間：噴射應(yīng)在前層混凝土終凝后進(jìn)行。Interval:Sprayingshouldbecarriedoutafterthefinalizationoftheupperconcrete.二、噴射混凝土Shotcrete噴射混凝土的施工Constructionofshotcrete3.噴射分區(qū)和順序Spraypartitionandsequence原則——分段、分片、分層、由下而上的順序進(jìn)行；Principles-segmentation,sharding,stratification,bottom-uporder;分段長度——基本段長:6m，分三小段長:2m、高:1.5m；Segmentlength-basicsegmentlength:6m,threesub-segments:2m,height:1.5m;要點(diǎn)——噴頭均勻緩慢地按順時(shí)針方向作螺旋形移動(dòng)，繞圈直徑為20～30cmPoints-Thenozzleismovedevenlyandslowlyinaspiraldirectioninaclockwisedirection,withadiameterof20to30cm二、噴射混凝土Shotcrete噴射混凝土的施工Constructionofshotcrete3.堵管問題Pluggingthepipeproblem原因：粗集料過大；水泥硬塊或其它雜物；干噴時(shí)混合料濕度過大致使摩擦力增大；輸料軟管彎頭過小及風(fēng)壓偏低等均能引起堵管。Cause:Coarseaggregateistoolarge;Cementhardblocksorotherdebris;Excessivehumidityofthemixtureduringdrysprayingleadstoincreasedfriction;Thefeedinghoseelbowistoosmallandthewindpressureislow,whichcancausethepipetobeblocked.處理：關(guān)閉馬達(dá)，隨后關(guān)閉風(fēng)源，噴射手將軟管拉直，然后用手錘敲擊以尋找堵管處；將風(fēng)壓升到0.3～0.4MPa（不超過0.5MPa），并用錘擊堵塞部位，使其暢通。排除堵管時(shí)，噴嘴前方嚴(yán)禁站人，以免被噴傷。Treatment:Turnoffthemotor,thenturnoffthewindsource,thesprayerstraightensthehose,andthenstrikeswithahandhammertofindtheblockage;Raisethewindpressureto0.3to0.4MPa(nomorethan0.5MPa),anduseahammertoblockthesitetomakeitunobstructed.Wheneliminatingtheblockage,itisstrictlyforbiddentostandinfrontofthenozzletoavoidbeingsprayed.二、噴射混凝土Shotcrete4.噴槍頭的操作Operationofthespraygunhead突然斷水、斷料時(shí)，噴頭應(yīng)移開受噴面；嚴(yán)禁用高壓風(fēng)、高壓水沖擊剛噴好的混凝土；Whenthewaterissuddenlycutoffandthematerialisbroken,thesprinklerheadshouldberemovedfromthesprayedsurface;Itisstrictlyforbiddentousehigh-pressurewindandhigh-pressurewatertoimpactthefreshlysprayedconcrete;受噴面敷設(shè)有金屬網(wǎng)時(shí)，水灰比宜稍大，噴咀與受噴面的距離也要相應(yīng)縮短到0.7m左右。Whenthesprayedsurfaceisequippedwithametalmesh,thewaterashratioshouldbeslightlylarger,andthedistancebetweenthenozzleandthesprayedsurfaceshouldbeshortenedtoabout0.7m.5.噴射混凝土的養(yǎng)護(hù)Maintenanceofshotcrete噴混凝土終凝后2h起即應(yīng)開始灑水養(yǎng)護(hù)；灑水次數(shù)以能保持混凝土具有足夠的濕潤狀態(tài)為度；Sprinklermaintenanceshouldbegin2hafterthefinalcoagulationofsprayedconcrete;Thenumberofsprinklesistotheextentthattheconcretecanbekeptinasufficientlymoiststate;養(yǎng)護(hù)期不得少于14d。Themaintenanceperiodshallnotbelessthan14days.二、噴射混凝土噴射混凝土的施工Constructionofshotcrete6.噴射混凝土強(qiáng)度、厚度檢驗(yàn)Shotcretestrengthandthicknessinspection（1）用噴大板切割試塊（100mm的立方體），在標(biāo)準(zhǔn)養(yǎng)護(hù)條件下進(jìn)行養(yǎng)護(hù)，噴射混凝土3h強(qiáng)度應(yīng)達(dá)到1.5MPa，24h應(yīng)達(dá)到10.0Mpa，28d用測(cè)得的極限抗壓強(qiáng)度乘以0.95。(1)Cutthetestblock(100mmcube)withasprayplate,maintainitunderstandardmaintenanceconditions,thestrengthoftheshotcreteshouldreach1.5MPaat3h,10.0Mpaat24h,andmultiplythemeasuredultimatecompressivestrengthby0.95for28d.（2）當(dāng)不具備制作抗壓強(qiáng)度標(biāo)準(zhǔn)塊條件時(shí)，可噴制混凝土大板，在標(biāo)準(zhǔn)條件下養(yǎng)護(hù)7d后，用鉆芯機(jī)取芯制作試塊，芯樣邊緣至大板周邊最小距離不小于50mm。(2)Whenthereisnostandardblockconditionformakingcompressivestrength,theconcreteslabcanbesprayed,andafter7dmaintenanceunderstandardconditions,thecoreisusedtomakeatestblockwiththecoremachine,andtheminimumdistancefromtheedgeofthecoresampletotheperipheryofthelargeplateisnotlessthan50mm.二、噴射混凝土噴射混凝土的施工Constructionofshotcrete6.噴射混凝土強(qiáng)度、厚度檢驗(yàn)Shotcretestrengthandthicknessinspection（3）可直接向邊長150mm的無底標(biāo)準(zhǔn)試模內(nèi)噴混凝土制作試塊，抗壓加載方向應(yīng)與試塊噴射成型方向垂直，其抗壓強(qiáng)度換算系數(shù)應(yīng)通過試驗(yàn)確定。(3)Itcanbedirectlysprayedconcreteintothebottomlessstandardtestmoldwithasidelengthof150mmtomakeatestblock,andthepressureloadingdirectionshouldbeperpendiculartothespraymoldingdirectionofthetestblock,andthecompressivestrengthconversioncoefficientshouldbedeterminedbytest.（4）噴層厚度的檢查。可用插針、鑿孔等方法檢查。噴射時(shí)可插入長度比設(shè)計(jì)厚度大5cm的粗鐵絲，縱、橫向1～2m設(shè)一根作為施工控制用。(4)Inspectionofthethicknessofthespraylayer.Itcanbecheckedbymeansofpins,chisels,etc.Duringinjection,athickwirewithalengthof5cmlargerthanthedesignthicknesscanbeinserted,andonecanbesetupinthelongitudinalandtransverse1to2mforconstructioncontrol.鋼纖維噴混凝土Steelfibersprayconcrete1.鋼纖維噴混凝土：是在普通砂漿或混凝土中摻入分布均勻且離散的鋼纖維，依靠壓縮空氣高速噴射在結(jié)構(gòu)表明的一種新型復(fù)合材料。1.Steelfibersprayedconcrete:itisanewtypeofcompositematerialthatismixedintoordinarymortarorconcretewithuniformdistributionanddiscretesteelfiber,relyingoncompressedairtosprayathighspeedinthestructure.鋼纖維噴混凝土Steelfibersprayconcrete2.噴射優(yōu)點(diǎn)Sprayadvantages全自動(dòng)化的噴射機(jī)械用活塞泵可達(dá)到25m3/h的噴射能力；Fullyautomatedpistonpumpforinjectionmachinerycanreachasprayingcapacityof25m3/h;僅5%～10%的回彈率，比干噴低的多；Only5%to10%ofthereboundrate,muchlowerthandryspray;混凝土質(zhì)量均一，通常強(qiáng)度可達(dá)55MPa,彎曲拉伸及抗剪強(qiáng)度大；Thequalityofconcreteisuniform,usuallythestrengthcanreach55MPa,bendingtensileandshearstrengthislarge;耐沖擊、抗凍融性好。Goodimpactresistance,freeze-thawresistance.鋼纖維噴混凝土Steelfibersprayconcrete3、鋼纖維噴混凝土的原材料及其配合比Rawmaterialsforsteelfibersprayedconcreteandtheirmixratios鋼纖維：直徑一般為0.3～0.5mm，長為20～25mm，長徑比為40～60，摻量：混合料重量的3.0～