基坑支護(hù)外文文獻(xiàn)

.中文3700字Soilnailwall,alsoknownassoilnailingtechnology,whichisinstalledinsitusoilwitharelativelydensesoilnails,andsoilslopesurfaceofsprayedconcretetobuildasteelmeshsurfacelayer,throughthesoilnails,thesurfacelayerandin-situsoiltheroleofthethreecommonslopeorretainingwallside.Soilnailwallsbutalsoposesasimilargravityinsitureinforcedearthretainingstructures.Andsupportingavarietyofmethodshavebeencompared,ithastheconstructioneasy,simpleequipment,requirelittlespace,excavationandsupportingjobscanbeparallel,theoverallprogressofthefast,lowcost,aswellaspollution,lownoise,stableandreliable,socialandeconomicgood,andmanyotheradvantages,andthereforeathomeandabroadwiththefoundationpitslopereinforcementhasbeenwidelyappliedrapidly.Soilnailwallconstructiontechnologyisatop-downstepbystepbuildprocess,accordingtothefollowingorder:Accordingtodesignrequirementsforexcavationface,trimmedslope,plantedsprayedconcretethicknesscontrolsigns;jetfirstlayerofconcrete;erectionofdrillingsoilnails,grouting,erectionofconnectors;bandingsteelnet,sprayasecondlayerofconcrete;settopofthehill,slopeandthefootoftheslopeofthedrainagesystem.Soil-nailedlaw-enforcement:keepasmuchaspossible,significantlyhighermaximumuseofpitwallsideofinherentmechanicalstrengthofsoil,changingsoilstructureandsystemloadaspartofthebracing.Sprayedconcreteundertheeffectofhighpressuregasflow,whereinhigh-speedsoilsurfacelayerandtheWord資料.soilinthespraycreatedbetween'embeddedsolid-effect',andgraduallyformacompletelyclosedwiththeexcavationshoringsystems,spraylayerandmountedwithaprotectivelayerofandreinforcementoftopsoil,sothattoavoidexposuretowindandrainerosion,shallowcollapse,localspalling,aswellastheroleofimpermeableimpermeable.Soilnailingaspecialcontrolpressuregroutingcanbereinforcedmediumgreatlyimprovedphysicalandmechanicalpropertiesmakeitbecomeanewgeologicalbody,itssolid-solidintheslipplanethedeepsectionofthesoiloutsidethehouse,itsexternalfixedterminalSpraythesurfacelayerinconjunctionwiththenetworkasawholemaybeatendencytoinstabilityinthesidewalltransferredtothesolid-sectionanditsvicinityandtoeliminate.ReinforcedMeshsprayedlayercanhaveabetterintegrityandflexibility,caneffectivelyadjustthespraylayerandthestressdistributionwithinthesoilnail.Activesoilnailretainingsoilandwithsoiltogetherwithconstructionofsimple,rapidandtimely,flexibleapplicability,withthediggingwithsticks,safeandeconomiccharacteristics.Itsdurationisgenerallypoorerthanthetraditionalmethodtosavemorethan30-60d,engineering,lowcostand10%-30%,supportingthemaximumverticalpitdepthhasnowreached21.5m,builtmud(localmiscellaneousfill)pitdepthof10m.Thismethodnotonlyeffectivelybeusedforgeneralgeotechnicaldeepexcavationshoring,oftenalsousedanumberofotherancillarysupportmeasures,caneffectivelybeusedforsupportingstreamingsand,silt,complexfilling,saturatedsoil,softsoil,etc.adversegeologicalconditionsofthedeepexcavation.Inaddition,itisalsorapid,Word資料.reliableandeconomicalmethodofusingthetraditionalmethodorimprovedfacilitiestobemadeorhavebeencarriedoutrescueexcavationinstabilityreinforcement.Ofsoilnailingandreinforcedsoilandanchoritseemssuchasretainingstructures,however,thestructureofsoilnailingandreinforcedearthconstruction,etc.Therearemanydifferentpoints,andanchor.Firstofall,soilnailingandreinforcedsoilslopeorretainingwallisnotthesame,mainlyreflectedin:theconstructionindifferentways.Soil-nailedconstructionofthedistributionofexpansionfromtoptobottom,sideexcavationwhileretainingfulluseofundisturbedsoilstrength.Reinforcedearthstructurefrombottomtotopfillinglayeredconstruction,fillingchoice,densityandintensitycanbecontrolled;reinforcedpullthebiggestchangesinbodypatternisdifferent.Inthereinforcedearthstructure,thegeneralbodyatthebottomofthetendonforcemaximum.Inthestructureofsoilnailing,thegeneralrangeofthecentralpartofthelargestforceofsoilnail,theupperandbottomofthesoilnailforcesmall;differentdeformationproperties.SoilNailingthemaximumdisplacementoccurredinthesupportingslopeatthetopornearthetop,reinforcedearthstructure,themaximumdisplacementatthebottom.Secondly,soilnailingandboltingorretainingwallisnotthesame,mainlydueto:thevariouspartsoftheforceandthesamerole.Boltingorretainingwalloftheanchorgenerallyanchoragesectionandfreeabove,theuseofslidingsurfacetoprovideresistanceoutsidetheanchoragesection,settheanchorWord資料.generallyprestressed,thefreesectionunderuniformtensioneffect,throughtheanchorseatpassedtotheslopeoftheretainingstructures,earthretainingstructuresgreaterstiffness,mainlythroughtheprovisionofresistancebythemoment,isoneofthemainforcecomponents.Soilnailingsettingsgenerallydonotimposepre-tension,butoccursinthesoilafterasmalldeformationofthepassiveforce,thesizeoftheforcealongtheunevendistributionofsoilnailextension,themiddleonbothsidesofthesmall,theroleoftheforceatthesurfacelayerthanthesmall,sprayedconcretesurfacelayerisnotamajorforcecomponents,itsroleistostabilizethesurfaceofthepartialexcavationofsoiltopreventcavinganderosion;settingdifferentdensities.Intheboltsupportintheunitareaontheretainingboltsetthenumberofgenerallyless,foreachrootanchorconstructionaccuracyandrequirementsareverystringent.Inthesoil-nailing,thesurfaceofsoilnailretainingalittlebitmoredensearrangementofindividualsoilnailconstructionrelativelylowaccuracyandqualityrequirements;designofdifferentlengths.Intheboltsupport,thedesignrequirementsmustmeettherequirementsofeachrootanchorofresistance,soboltanchoragesectionrequirein-depthintothestablelayer,thedesignofalongerlength.Insoilnailing,themoredensearrangementofsoilnail,thelargenumberofinteractionwiththesurroundingsoil,tomaintainself-reinforcedzoneofsoilstability,andresistancetooutsidetheregionreinforcedtheroleofsoilpressure,designshorterlength.Ofcourse,therearemanytypesofbolts,therearenotpre-stressed,thelengththantheaveragesoil-nailevenshorter,butthisWord資料.boltismainlyusedforthetunnelorundergroundworksofthespray-anchoronthelengththantheaveragesoil-nailisalsoisshorter,oftenonly2-4m.（1）ConstructionofSoilNailSoilnailingisasoil-nailasamajorcomponentoftheslopeoftheforcesupportingtechnology,whichconsistsofdensesoilnailgroup,hasbeenreinforcedinsitusoil,sprayedconcretesurfacelayerandthenecessarywatersystemcomponents.（2）StructuralMaterialsSteel:steeltypes,modelsandsizesshouldbeconsistentwithdesignrequirements,shouldadopttheH-orH-classsteelworkers,reinforcedafterthepurchaseshouldbeproperlysafeguardedtopreventcorrosion,productionshouldbetransferredstraight,rust,oilremoval,shouldbecarriedoutphysicalandmechanicalpropertiesorchemicalcompositionanalysisoftestweldingofsteel,shouldbeweldabilityandweldingqualityofthetestfordetectionofweldingmaterialstrengthshouldbegreaterthantheoverallstrength;Cement:ordinaryportlandcementused,labelP032.5,ifnecessary,sulfuricacidresistantcement,aluminacementshouldnotbeused.Cementshouldcomplywiththeprovisionsoftheexistingcementstandardrequirements,theremustbeasinglefactorytestreports,qualityinspectionorders,factorycarddocuments,inaccordancewithitsvarieties,label,testnumbersetc.,andinspectionandacceptancesamplinginspection,bytheexaminationresultsarereasonableUse.BagsofcementshouldbeproperlykeptinstorageandWord資料.transportation,rain,moisture,stackedinacertainheightfromthegroundheapshelves,isstrictlyprohibitedanddamagethrowingthrowingbags,prohibitedtheuseofdampordifferentvarietiesofmixedcementlabel.Aggregate:stoneandsandmaterial(seedsfilm,medium-finesand)shouldcheckreportcards,thestonetestmethodsandqualitystandardsbyJGJ53-92,sandmaterialtestingmethodsandqualitystandardsbyJGJ52-92.Particlesizeoflessthan2mminthesand,sand,claycontentbyweightnotmorethan3%,theparticlesizeoflessthan12mmgravelormelontablets,claycontentbyweightnotmorethan3%.Mixingofwater:thewaterwithoutaffectingthenormalcondensationofcementhardeningofharmfulimpurities,maynotcontainfat,sugarandfreeacid,etc.;water,PHvalueislessthanfourofacidicwaterandsulfurionofmorethan1%ofthewaterweightofwaterwereshallnotbeused;theuseoftapwaterorcleanwaterformixingnaturalwatercouldbedispensedwithfortesting.Quick-settingagent:quick-settingagentisusedinJ85,711,orRedStar1,shouldbespecificallyresponsibleforcontrol,addtheweightof3%oftheweightofcement,themachineautomaticallyaddedbythejet.Electrodes:TheTHJ422.Concretemix:Inadditiontosprayingtheconcretemixdesignstandardstobeattainedstrength,wemustalsomeetthetechnicalrequirementsofconstruction,withtheratioof1:0.4:2:2(cement:water:sand:melonpieces),melonseedspiecemaximumdiameterofnotmorethan12mm.Word資料.Groutingmixtureratio:one-groutingwithcementmortar1:1,thesecondgroutingusingwater-cementratioof0.5waterslurry,cementmortarandcementslurrymustbestirredevenlypure,amixingoftheslurrymustbeinitialsettingbefore(generally2h)runout.Earlystrengthandwater-reducingagent:Accordingtothenatureofprojects,usingdifferenttypesofearlystrengthagent,commonlyusedredstaronthe4th,3F,NC,NNOF,NS2-1andsoon.（3）NetproductionofsoilnailingandreinforcedSizeallowabledeviationofsoilnailmaking:thelengthof??100mm,curvedrepostedelsewhereinthepaperforfreedownload.hi138.（4）DrainageSystemSoilNailingappropriatetoremovegroundwaterundertheconditionsofconstruction,thedrainageshouldtakeappropriatemeasures,includingsurfacedrainage,internaldrainage,aswellassupportingthedrainagepitinordertoavoidsaturationofthesoilandreducetheroleofthehydrostaticlayeronthesurfacepressure.Excavationaroundthebracingshouldbeaddedwithinthesurfacefinishing,andbuildingdrainsandcementmortarorconcretesurfacetotheundergroundwatersurfaceinfiltrationofprecipitation.Pittopofthehillnearthe2-4mwideandthegroundshouldbeproperlyboosted,andtheinsideofhighexternallow,easytorun-offawayfromtheslope.Insupportingthebacksurfacelayershouldbeinsertedinalengthof400-600mm,diameterofnotlessthanthestandardWord資料.40mmdrainoutitsexternalsidesupportingsurfacelayerspacingfor1.5-2m,inordertospraytheplotafterthesurfacelayerofconcretewaterdischarge.Toruleouttheaccumulatedwaterseepageinsidethepitandrainshouldbeset300mm300mmBottomdrains,leadstothe600mm*600mm*600mmsump.Drains,leavethesidewall0.5-1m,drainsandsumpisappropriatetobrickandmortarPlasteringusedtopreventleakage,pitwatershouldbeoutintime.Mechanismofcompositesoilnailforce. Inthesoilnailingsystem,thesoilnailisanimportantforcecomponents,theroleofsoilnailwillactonthesurfacelayerorsoil-cementpileonthewater,soilpressure,soilnailandsoilthroughthemillpassedtothestabilityoftheresistanceFormationtogo,similartothesoilanchor;throughthedenseandthesoilnailswillbeashortretainingbodydeformationHoutuboundtogethertoformfromthesoil,groutingandsoilnailingbodyacompositesoil,compositesoilsimilartotheontheforceofgravitydam.Thisroleissimilartoreinforcedearthretainingpit;nomatterwhatformofconstructionofsoilnail(hole-drillingmethod,andenteringthelawandtheroofintothelaw),soilnailingchannelsaregroutingholes,whichnotonlyformedasoilgroutingnailretainingwallandtheformationoffrictionbetweenthebelt,atthesametimeinordertosplit,penetrationandcompactiongroutingintheformofreinforcedretainingHoutubody,sucharolesimilartothemechanismofcompactiongrouting.TheprocessofsoilnailforceMeasurementsshowedthattheprocessofsoilnailforcecanbedividedintothreestages:Word資料.PhaseI:soilnailinstalledanearlystage,butthecompletionofgroutinggroutingofthebondingbetweenthebodyandthesoilhasnotbeenformed,whenthesoilnaillargelyunaffectedbypower.PhaseII:groutingbodyofthesoilnailbondingintheformation,withtheexcavationdepthincreases,soilnailinghastheeffectoftension,andtensionconcentratedinthesurfacelayerbondedwiththesite,theninternalforcedistributionissimilartonon-Free-formdeformationofthesoilanchorsegmentnearthesurfacelayeratthebiggestrally,thesubsequentdecreasegradually.Thethirdphase:excavationofsufficientdepth,soilnailingmostoftheslipattherange.Atthistimetheperformanceofsoilnailingforthemiddleofinternalforce(neartheslipsurface)thelargestandthesmallestatbothends.Forcedistributionissimilartoreinforcedearthretainingwallinthestretch.Word資料.土釘墻又稱為土釘支護(hù)技術(shù)，它是在原位土中敷設(shè)較為密集的土釘， 并在土邊坡表面構(gòu)筑鋼絲網(wǎng)噴射混凝土面層， 通過土釘、面層和原位土體三者的共同作用而支護(hù)邊坡或邊壁。土釘墻體同時也構(gòu)成了一個就地加固的類似重力式擋土結(jié)構(gòu)。與已有的各種支護(hù)方法相比，它具有施工容易、設(shè)備簡單、需要場地小，開挖與支護(hù)作業(yè)可以并行、總體進(jìn)度快、成本低，以及無污染、噪聲小、穩(wěn)定可靠、社會效益與經(jīng)濟(jì)效益好等許多優(yōu)點(diǎn)， 因而在國外的邊坡加固與基坑支護(hù)中得到了廣泛迅速的應(yīng)用。土釘墻的施工技術(shù)是一種由上而下分步修建的過程，可按下列順序進(jìn)行 :按設(shè)計要求開挖工作面，修整邊坡，埋設(shè)噴射混凝土厚度控制標(biāo)志 ;噴射第一層混凝土;鉆孔安設(shè)土釘、注漿、安設(shè)連接件 ;綁扎鋼筋網(wǎng)，噴射第二層混凝土 ;設(shè)置坡頂、坡面和坡腳的排水系統(tǒng)。土釘支護(hù)法:以盡可能保持、顯著提高、最大限度地利用基坑邊壁土體固有力學(xué)強(qiáng)度，變土體荷載為支護(hù)結(jié)構(gòu)體系一部分。 噴射混凝土在高壓氣流的作用下高速噴向土層表面，在噴層與土層間產(chǎn)生“嵌固效應(yīng)”，并隨開挖逐步形成全封閉支護(hù)系統(tǒng)，噴層與嵌固層同具有保護(hù)和加固表層土，使之避免風(fēng)化和雨水沖刷、淺層坍塌、局部剝落，以及隔水防滲作用。土釘?shù)奶厥饪貕鹤{可使被加固介質(zhì)物理力學(xué)性能大為改善并使之成為一種新地質(zhì)體， 其固段深固于滑移面之外的土體部，其外固端同噴網(wǎng)面層聯(lián)為一體， 可把邊壁不穩(wěn)定的傾向轉(zhuǎn)移到固段及其附近并消除。鋼筋網(wǎng)可使噴層具有更好的整體性和柔性， 能有效地調(diào)整噴層與土釘應(yīng)力分布。土釘主動支護(hù)土體并與土體共同作用，具有施工簡便、快速及時，機(jī)動靈活、適用性強(qiáng)、隨挖隨支、安全經(jīng)濟(jì)等特點(diǎn)。其工期一般比傳統(tǒng)法節(jié)省 30-60d以上，工程造價低10%-30%，支護(hù)最大垂直坑深目前已達(dá)到 21.5m，建成淤泥(局Word資料.部雜填土)基坑深達(dá)10m。該方法不僅能有效地用于一般巖土深基坑工程支護(hù)，而且通常還采用一些其他輔助支護(hù)措施， 能有效地用于支護(hù)流砂、淤泥、復(fù)雜填土、飽和土、軟土等不良地質(zhì)條件下的深基坑。此外，它還能快速、可靠、經(jīng)濟(jì)地對采用傳統(tǒng)法或改良法施作的將要或已經(jīng)失穩(wěn)的基坑進(jìn)行搶險加固處理。土釘支護(hù)似乎與加筋土和錨桿等擋土結(jié)構(gòu)一樣， 然而土釘支護(hù)在結(jié)構(gòu)施工等方面與加筋土和錨桿有許多不同點(diǎn)。首先，土釘支護(hù)與加筋土邊坡或擋墻不相同，主要表現(xiàn)在 :施工方法不同。土釘支擴(kuò)從上到下分布進(jìn)行修建， 邊開挖邊支護(hù)，充分利用原狀土的強(qiáng)度。加筋土結(jié)構(gòu)由下到上分層填土構(gòu)筑，填料可以選擇，密實(shí)度和強(qiáng)度可以控制 ;加筋體最大拉力的變化規(guī)律不同。在加筋土結(jié)構(gòu)中，一般處于下部的筋體受力最大。 在土釘支護(hù)結(jié)構(gòu)中，一般介于中部的土釘受力最大，上部和底部的土釘受力較小 ;變形性能不同。土釘支護(hù)最大位移發(fā)生在支護(hù)邊坡頂部或接近頂部， 加筋土結(jié)構(gòu)的最大位移在底部。其次，土釘支護(hù)與錨桿支護(hù)或擋墻也不相同，主要在于 :各部分的受力和作用不同。錨桿支護(hù)或擋墻中的錨桿一般都有錨固段和自由段， 利用滑動面以外的錨固段提供抗力，設(shè)置錨桿一般要施加預(yù)應(yīng)力， 自由段受到均勻的拉力作用， 通過錨座傳遞到坡面的擋土構(gòu)件上， 擋土構(gòu)件的剛度較大，主要通過受彎矩提供抗力，是主要的受力部件之一。土釘設(shè)置后一般不施加預(yù)拉力， 只是在土體發(fā)生微小變形后才被動受力，受力的大小沿土釘延長的分布不均勻， 中間大兩邊小，所作用在面層上的力較小，噴射混凝土面層不是主要受力部件， 其作用是穩(wěn)定開挖面上的局部土體，防止崩落和受到侵蝕 ;設(shè)置密度不同。在錨桿支護(hù)中，單位支護(hù)面積上設(shè)置的錨桿數(shù)量通常較少，對每根錨桿的施工精度和要求都十分嚴(yán)格。Word資料.在土釘支護(hù)中，支護(hù)面上土釘排列得較密，對單個土釘?shù)氖┕ぞ群唾|(zhì)量要求相對較低;設(shè)計長度不同。在錨桿支護(hù)中，設(shè)計要求每根錨桿都要達(dá)到要求的抗力，所以錨桿的錨固段需要深入到穩(wěn)定的土層中， 設(shè)計長度較長。在土釘支護(hù)中，土釘排列較密，數(shù)量眾多，與周圍土層共同作用，能夠保持加固區(qū)土體的自身的穩(wěn)定，并抵抗加固區(qū)以外的土壓力的作用， 設(shè)計長度較短。當(dāng)然，錨桿有許多種類，也有不加預(yù)應(yīng)力、長度比一般的土釘還要短，但這種錨桿主要用于隧道或地下工程的噴錨支護(hù)上，長度比一般的土釘還要短，常用只有 2-4m。（1）土釘墻結(jié)構(gòu)組成土釘支護(hù)是以土釘作為主要受力構(gòu)件的邊坡支護(hù)技術(shù)，它由密集的土釘群、被加固的原位土體、噴射混凝土面層和必要的防水系統(tǒng)組成。（2）土釘墻結(jié)構(gòu)材料鋼材:鋼筋的種類、型號及尺寸規(guī)格應(yīng)符合設(shè)計要求，宜采用 H級或工H級鋼筋，鋼筋購進(jìn)后應(yīng)妥善保管，防止銹蝕，制作時應(yīng)調(diào)直、除銹、除油，應(yīng)進(jìn)行物理力學(xué)性能或化學(xué)成份分析試驗(yàn)， 焊接用的鋼材，應(yīng)作可焊性和焊接質(zhì)量的試驗(yàn)檢測其焊接強(qiáng)度應(yīng)大于材料整體強(qiáng)度 ;水泥:采用普通硅酸鹽水泥，