隧道施工项目六支护施工38课件

Tunnelconstruction

隧道施工

项目六支护施工Project6Supportconstruction任务一初期支护Initialsupport——喷射混凝土施工Shotcreteconstruction学习目标Learningobjectives2知识目标Knowledgeobjectives能力目标Competencyobjectives通过本任务的学习，学生应掌握喷射混凝土的施工工艺流程；掌握喷射混凝土施工过程中的质量控制要点；Throughthestudyofthistask,studentsshouldmastertheconstructionprocessofshotcrete;Masterthekeypointsofqualitycontrolintheconstructionprocessofshotcrete;通过本任务的学习，学生应能初步具备喷射混凝土工程施工及质量控制能力、编制喷射混凝土作业技术交底的能力。Throughthestudyofthistask,studentsshouldbeabletoinitiallyhavetheabilityofsprayedconcreteengineeringconstructionandqualitycontrol,andtheabilitytoprepareshotcreteworktechnology.二、喷射混凝土Shotcrete喷射混凝土的施工Constructionofshotcrete1.施工准备Constructionpreparation（1）工、料、机的准备：人工、材料、机械（具）的准备，核实品种、质量要求、足够储备量。喷射机械的就位，并试运转。(1)Preparationofwork,materialsandmachines:preparationoflabor,materials,machinery(equipment),verificationofvarieties,qualityrequirements,andsufficientreserves.Thejettingmachineryisinplaceandcommissioned.（2）湿喷场地的准备：检查隧道开挖断面的净空尺寸；冲洗受喷岩面；作喷射混凝土的厚度的标志；施工平面的布置，应满足施工工艺的要求；布置应力求紧凑，充分利用场地空间及运输线，避免施工干扰。Preparationofwetspraysites:checktheclearancedimensionsofthetunnelexcavationsection;Flushingofthesprayedrocksurface;Asasignofthethicknessofshotcrete;Thelayoutoftheconstructionplaneshouldmeettherequirementsoftheconstructionprocess;Thelayoutshouldbecompact,makefulluseofthesitespaceandtransportationlines,andavoidconstructioninterference.二、喷射混凝土Shotcrete喷射混凝土的施工Constructionofshotcrete2.施喷作业Sprayingoperations（1）喷嘴与受喷岩面之间的距离和角度(1)Thedistanceandanglebetweenthenozzleandthesurfaceofthesprayedrock喷嘴与受喷岩面之间的最优距离是按喷混凝土的最高强度和最小回弹量来确定的，一般以0.6～1.8m为宜。角度：垂直喷射向受喷面，困难部位倾斜不大于10°。Theoptimaldistancebetweenthenozzleandthesurfaceofthesprayedrockisdeterminedbythemaximumstrengthandminimumreboundofthesprayedconcrete,anditisgenerallyappropriateto.8m0.6to1.Angle:Verticalspraytothesprayedsurface,thedifficultpartistiltednotmorethan10°.（2）厚度和间隔时间Thicknessandintervaltime根据喷射效率、回弹损失等因素确定，拱部一次喷射厚度6~10cm，侧壁为8~10cm。Accordingtotheinjectionefficiency,reboundlossandotherfactors,thearchis6to10cmthickatatime,andthesidewallis8to10cm.间隔时间：喷射应在前层混凝土终凝后进行。Interval:Sprayingshouldbecarriedoutafterthefinalizationoftheupperconcrete.二、喷射混凝土Shotcrete喷射混凝土的施工Constructionofshotcrete3.喷射分区和顺序Spraypartitionandsequence原则——分段、分片、分层、由下而上的顺序进行；Principles-segmentation,sharding,stratification,bottom-uporder;分段长度——基本段长:6m，分三小段长:2m、高:1.5m；Segmentlength-basicsegmentlength:6m,threesub-segments:2m,height:1.5m;要点——喷头均匀缓慢地按顺时针方向作螺旋形移动，绕圈直径为20～30cmPoints-Thenozzleismovedevenlyandslowlyinaspiraldirectioninaclockwisedirection,withadiameterof20to30cm二、喷射混凝土Shotcrete喷射混凝土的施工Constructionofshotcrete3.堵管问题Pluggingthepipeproblem原因：粗集料过大；水泥硬块或其它杂物；干喷时混合料湿度过大致使摩擦力增大；输料软管弯头过小及风压偏低等均能引起堵管。Cause:Coarseaggregateistoolarge;Cementhardblocksorotherdebris;Excessivehumidityofthemixtureduringdrysprayingleadstoincreasedfriction;Thefeedinghoseelbowistoosmallandthewindpressureislow,whichcancausethepipetobeblocked.处理：关闭马达，随后关闭风源，喷射手将软管拉直，然后用手锤敲击以寻找堵管处；将风压升到0.3～0.4MPa（不超过0.5MPa），并用锤击堵塞部位，使其畅通。排除堵管时，喷嘴前方严禁站人，以免被喷伤。Treatment:Turnoffthemotor,thenturnoffthewindsource,thesprayerstraightensthehose,andthenstrikeswithahandhammertofindtheblockage;Raisethewindpressureto0.3to0.4MPa(nomorethan0.5MPa),anduseahammertoblockthesitetomakeitunobstructed.Wheneliminatingtheblockage,itisstrictlyforbiddentostandinfrontofthenozzletoavoidbeingsprayed.二、喷射混凝土Shotcrete4.喷枪头的操作Operationofthespraygunhead突然断水、断料时，喷头应移开受喷面；严禁用高压风、高压水冲击刚喷好的混凝土；Whenthewaterissuddenlycutoffandthematerialisbroken,thesprinklerheadshouldberemovedfromthesprayedsurface;Itisstrictlyforbiddentousehigh-pressurewindandhigh-pressurewatertoimpactthefreshlysprayedconcrete;受喷面敷设有金属网时，水灰比宜稍大，喷咀与受喷面的距离也要相应缩短到0.7m左右。Whenthesprayedsurfaceisequippedwithametalmesh,thewaterashratioshouldbeslightlylarger,andthedistancebetweenthenozzleandthesprayedsurfaceshouldbeshortenedtoabout0.7m.5.喷射混凝土的养护Maintenanceofshotcrete喷混凝土终凝后2h起即应开始洒水养护；洒水次数以能保持混凝土具有足够的湿润状态为度；Sprinklermaintenanceshouldbegin2hafterthefinalcoagulationofsprayedconcrete;Thenumberofsprinklesistotheextentthattheconcretecanbekeptinasufficientlymoiststate;养护期不得少于14d。Themaintenanceperiodshallnotbelessthan14days.二、喷射混凝土喷射混凝土的施工Constructionofshotcrete6.喷射混凝土强度、厚度检验Shotcretestrengthandthicknessinspection（1）用喷大板切割试块（100mm的立方体），在标准养护条件下进行养护，喷射混凝土3h强度应达到1.5MPa，24h应达到10.0Mpa，28d用测得的极限抗压强度乘以0.95。(1)Cutthetestblock(100mmcube)withasprayplate,maintainitunderstandardmaintenanceconditions,thestrengthoftheshotcreteshouldreach1.5MPaat3h,10.0Mpaat24h,andmultiplythemeasuredultimatecompressivestrengthby0.95for28d.（2）当不具备制作抗压强度标准块条件时，可喷制混凝土大板，在标准条件下养护7d后，用钻芯机取芯制作试块，芯样边缘至大板周边最小距离不小于50mm。(2)Whenthereisnostandardblockconditionformakingcompressivestrength,theconcreteslabcanbesprayed,andafter7dmaintenanceunderstandardconditions,thecoreisusedtomakeatestblockwiththecoremachine,andtheminimumdistancefromtheedgeofthecoresampletotheperipheryofthelargeplateisnotlessthan50mm.二、喷射混凝土喷射混凝土的施工Constructionofshotcrete6.喷射混凝土强度、厚度检验Shotcretestrengthandthicknessinspection（3）可直接向边长150mm的无底标准试模内喷混凝土制作试块，抗压加载方向应与试块喷射成型方向垂直，其抗压强度换算系数应通过试验确定。(3)Itcanbedirectlysprayedconcreteintothebottomlessstandardtestmoldwithasidelengthof150mmtomakeatestblock,andthepressureloadingdirectionshouldbeperpendiculartothespraymoldingdirectionofthetestblock,andthecompressivestrengthconversioncoefficientshouldbedeterminedbytest.（4）喷层厚度的检查。可用插针、凿孔等方法检查。喷射时可插入长度比设计厚度大5cm的粗铁丝，纵、横向1～2m设一根作为施工控制用。(4)Inspectionofthethicknessofthespraylayer.Itcanbecheckedbymeansofpins,chisels,etc.Duringinjection,athickwirewithalengthof5cmlargerthanthedesignthicknesscanbeinserted,andonecanbesetupinthelongitudinalandtransverse1to2mforconstructioncontrol.钢纤维喷混凝土Steelfibersprayconcrete1.钢纤维喷混凝土：是在普通砂浆或混凝土中掺入分布均匀且离散的钢纤维，依靠压缩空气高速喷射在结构表明的一种新型复合材料。1.Steelfibersprayedconcrete:itisanewtypeofcompositematerialthatismixedintoordinarymortarorconcretewithuniformdistributionanddiscretesteelfiber,relyingoncompressedairtosprayathighspeedinthestructure.钢纤维喷混凝土Steelfibersprayconcrete2.喷射优点Sprayadvantages全自动化的喷射机械用活塞泵可达到25m3/h的喷射能力；Fullyautomatedpistonpumpforinjectionmachinerycanreachasprayingcapacityof25m3/h;仅5%～10%的回弹率，比干喷低的多；Only5%to10%ofthereboundrate,muchlowerthandryspray;混凝土质量均一，通常强度可达55MPa,弯曲拉伸及抗剪强度大；Thequalityofconcreteisuniform,usuallythestrengthcanreach55MPa,bendingtensileandshearstrengthislarge;耐冲击、抗冻融性好。Goodimpactresistance,freeze-thawresistance.钢纤维喷混凝土Steelfibersprayconcrete3、钢纤维喷混凝土的原材料及其配合比Rawmaterialsforsteelfibersprayedconcreteandtheirmixratios钢纤维：直径一般为0.3～0.5mm，长为20～25mm，长径比为40～60，掺量：混合料重量的3.0～