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外文文献及中文翻译英文题目THEDISCUSSIONOFTHEPROBLEMINTHEHOLEEXCAVATEDFORBUILDINGFOUNDATIONSUPPORTSANDPROTECTIONSAPPLICATIONWITCHTHEWATERSOILAGITATIONPILEHAS中文题目水泥土搅拌桩在基坑支护应用中存在问题的探讨专业勘察技术与工程姓名THEDISCUSSIONOFTHEPROBLEMINTHEHOLEEXCAVATEDFORBUILDINGFOUNDATIONSUPPORTSANDPROTECTIONSAPPLICATIONWITCHTHEWATERSOILAGITATIONPILEHASABSTRACTTHEWATERSOILAGITATIONPILESERVESASTHEHOLEEXCAVATEDFORBUILDINGFOUNDATIONSUPPORTSANDPROTECTIONS,BECAUSEITSELFEXISTSFLAW,IFDOESNOTPERFORMTOSOLVE,WILLRELATETHEENTIRESUPPORTSANDPROTECTIONSTHESUCCESSORFAILURE,SERIOUSPOSSIBLYCAUSESTHEACCIDENT,MUSTBRINGTOTHEATTENTIONKEYWORDHOLEEXCAVATEDFORBUILDINGFOUNDATIONSUPPORTSANDPROTECTIONSWATERSOILAGITATIONPILE1FOREWORDAFTERWORLDWARII,THEUSFIRSTDEVELOPEDINDEPTHPUDDLEPROCESS,OURCOUNTRYINTRODUCESSUCCESSFULLYIN1977,IN1980APPLIEDOFFICIALLYINTHEPROJECTPRACTICE,AFTERMORETHAN20YEARSDEVELOPMENT,THEPROMOTION,OBTAINEDTHEWIDESPREADAPPLICATIONINOURCOUNTRYSSOFTSOILAREA,THEDEVELOPMENTISRAPIDTHEWATERSOILAGITATIONPILEUSESINTHEDEEPHOLEEXCAVATEDFORBUILDINGFOUNDATIONSUPPORTSANDPROTECTIONSFUNCTIONTHECONTINUALWALL,ALSOCALLSTHESMWLABORLAWOURCOUNTRYINTRODUCESTHISLABORLAWBYTHEBAOSHANSTEELCORPORATIONPROJECTTOTAKETHEBUILDINGENCLOSUREMOSTEARLY,AFTERWARDINNATIONALPROMOTIONTHISKINDOFLABORLAWCONSTRUCTIONDISTURBSFEW,TOSOFTGROUNDCOMPATIBLE,ANDHASTHESTRUCTURESIMPLY,TOCONSTRUCTTOTHESURROUNDINGSAFFECTS,THETIMETOBESHORTSLIGHTLY,THECONSTRUCTIONCOSTISLOW,ENVIRONMENTALPOLLUTIONSMALLANDSOONMERITS,ANDMAYMAKETHESEEPPROOFSCREENTOBEPOSSIBLETOTAKETHEBULKHEAD,THEREFORETHEDEPTHISWELCOME2WATERSOILAGITATIONPILEOUTLINESTHEWATERSOILAGITATIONPILEISBECOMESTHROUGHNEIGHBORINGCEMENTEARTHPILEJOINING,USESTHECEMENTTOTAKETHEFIRMINGAGENT,THROUGHTHESPECIALPURPOSERABBLINGMECHANISM,FORMSTHESOFTSOILANDTHECEMENTCOMPULSIONAGITATIONTHEWATERSOIL,BETWEENTHEUSECEMENTANDTHESOFTSOILPRODUCESASERIESOFPHYSICS,THECHEMICALACTION,MAKESTHEWATERSOILINTENSITYTOGROW,BECOMESTHEWATERSOILPILE,AFTERTHEHARDENING,FORMSHASCERTAININTENSITYCEMENTWALLSHAPERETAININGWALL3EXISTENCEQUESTIONSANDCORRECTIVEMEASUREHOWEVER,BECAUSEATPRESENTTHEWATERSOILAGITATIONPILESCONSTRUCTIONQUALITYISIRREGULAR,THEDIFFERENCEISVERYBIG,SOMEWHATAFFECTSTHEHOLEEXCAVATEDFORBUILDINGFOUNDATIONSECURITY,HASCREATEDSOMEACCIDENTSTHEREFORE,THISARTICLETHROUGHTHEANALYSISWATERSOILAGITATIONPILELABORLAWTHEQUESTIONWHICHEXISTSINTHEHOLEEXCAVATEDFORBUILDINGFOUNDATIONSUPPORTSANDPROTECTIONSAPPLICATION,DISCUSSESTHISTECHNICALTHEAPPLIEDRESEARCHNECESSITYANDTHEECONOMICVALUE,CEASESTHEACCIDENTTOOCCUR31COMPATIBLEQUESTIONINTHEAGITATIONPILECONSTRUCTIONPROCESS,WILLOFTENBUMPINTOWILLSTIRAFTERCERTAINDEPTH,CANNOTCONTINUETHEQUESTIONWHICHWILLSNEAK,THISMUSTINVESTIGATEITSREASONFROMTHEAGITATIONPILETHISKINDOFLABORMETHODAPPLICABLESCOPEANYSOFTSOILGROUNDTREATMENTMETHODCANONLYBEBASEDONTHISSUITABLE,NAMELYINTECHNOLOGYINFEASIBILITYANDECONOMYRATIONALITYWHENPLANCHOICE,SHOULDEMBARKFROMTHECONCRETETERM,UNIFIESEACHKINDOFLABORMETHODCHARACTERISTIC,CHOOSESTHEMOSTAPPROPRIATECRAFTSIMILARLY,THEWATERSOILAGITATIONPILEALSOHASTHEADAPTATIONPROBLEM311SOILTEXTURECONDITIONSERVICEABILITYTHEWATERSOILAGITATIONPILEISSUITABLEGENERALLYFORTHESILT,THESILTARGILLACEOUSEARTH,THESILTYSOILANDTHEWATERCONTENTISHIGH,ANDTHEGROUNDSUPPORTINGCAPACITYNORMALVALUEISNOTBIGGERTHAN120KPAGROUNDSANDSOONCOHESIVESOILWHENUSESINTHEMARLYSOILORTHEGROUNDWATERHAVECORROSIVENESS,SUITABLYDETERMINESITSSERVICEABILITYTHROUGHTHEEXPERIMENT,WHENTHEWINTERCONSTRUCTIONSHOULDPAYATTENTIONTOTHENEGATIVETEMPERATURETOPROCESSTHEEFFECTTHEINFLUENCE312LOCATIONANDENVIRONMENTSERVICEABILITYWHENWATERSOILAGITATIONPILECONSTRUCTIONDOESNOTHAVETHEVIBRATION,NOTTOHAVETHENOISE,NOTTODUMPPOLLUTANTS,NOTLATERALTOPUSHTHEEARTHTOPLANSTOCONSTRUCTAROUNDTHELOCATIONTHEBUILDINGTOBECROWDED,THEPOPULATIONLIVESTOGETHER,HASEACHKINDOFUNDERGROUNDDUCTSPLACETOBEESPECIALLYAPPROPRIATE313PROJECTTYPESERVICEABILITYBECAUSEITSINTENSITYISNOTHIGH,WHENKEEPSOFFTHETEXTUREOFSOILASTHESTRUCTUREEXCAVATIONSUPPORTSANDPROTECTIONS,HASLIMITEDTHESUPPORTSANDPROTECTIONSDEPTH,GENERALLYCANNOTSURPASS46M32WATERSOILINTENSITYQUESTIONTHEWATERSOILSINTENSITYANDTHEEARTHNATURE,THECEMENTMIXTHEQUANTITY,THECONSTRUCTIONQUALITYANDSOONRELATED,THESOILTEXTUREMORESTICKS,THEINTENSITYTOBELOWERINTHEEARTHTHEORGANICCONFRONTATIONINTENSITYALSOHASTHEVERYTREMENDOUSINFLUENCEACCORDINGTOEXPERIMENTALANALYSIS,INSILTARGILLACEOUSEARTH,WHENTHECEMENTMIXESTHEQUANTITYISSMALLERTHAN12,ITSCOMPRESSIVESTRENGTHDOESNOTSURPASS08MPA,EVENISLOWERALSOSOMEPHENOMENONWHICHISNOTEWORTHY,INTENSITYEXPLOSIVEGROWTHTHEREFOREISSUITABLETHEQUALITYEVALUATIONMETHODSHOULDBETHECORESAMPLE,ORPREPARESTHEBRIQUETTEWITHTHEACTUALSOILSAMPLEPOSTPOSITIONEDINTHESUBMARINEMAINTENANCEWATERSOILWHICHMIXESUPINTHEUSUALCOHESIVESOIL,ALLOWSCOMPRESSEDSTRESS40CA06MPA,ALLOWSTHESHEARINGSTRESSCAA50,ALLOWSTHETENSILESTRESSCA15BUTSHOULDSATISFYMPCA2THEWATERSOILSINTENSITYWASNOTHIGHHASLIMITEDITSSUPPORTSANDPROTECTIONSALTITUDEMUSTTAKESERIOUSLYTOCONSTRUCTTHEQUALITY,SHOULDUSETHESLOWADVANCEMENT,LIVESINTHEDUPLICATETWOABOVEAGITATIONWAYENLARGESTHECEMENTEARTHTOMIXINSUITABLYISCOMPARABLEJOINSRIGHTAMOUNTOUTSIDEMIXESTHEMEDICINALPREPARATION,BUTENHANCESTHEPILESHAFTINTENSITYEFFECTIVELYINWHATTHEPRESENTHOLEEXCAVATEDFORBUILDINGFOUNDATIONSUPPORTSANDPROTECTIONSAPPLIESAREMANYAREAFTERPASSINGTHROUGHTHEFULLAGITATIONINTHEWATERSOILAGITATIONPILEINSERTSTHEBAMBOO,THEHSECTIONOROTHERMOLDINGINSERTIONAGITATIONPILEINVIVO,ENHANCESTHEWATERSOILAGITATIONPILETOPULLTHEINTENSITY,THUSPLAYSTHESUPPORTSANDPROTECTIONSROLEWELL33THEHORIZONTALDEPARTURECONTROLSTHEQUESTIONSERVESASTHEHOLEEXCAVATEDFORBUILDINGFOUNDATIONSUPPORTSANDPROTECTIONSTOCONTROLTHEHOLEEXCAVATEDFORBUILDINGFOUNDATIONDISTORTIONDISPLACEMENT,PREVENTSTHEDISTORTIONOVERSIZEDTOAFFECTTHEENVIRONMENT,THEPROJECTPILEFOUNDATIONANDTHEBASEMENTCONSTRUCTIONSHOULDACTACCORDINGTOTHESECURITYRATINGANDTHESCENEACTUALCONDITION,ALLOWSTHEDISPLACEMENTTHROUGHTHEREASONABLEDESIGNDETERMINATIONHOLEEXCAVATEDFORBUILDINGFOUNDATIONTOCONTROLTHEVALUE,THUSPERFORMSINTHECONSTRUCTIONPROCESSTOGUARDAGAINSTATPRESENTUSESINTHEMETHODWHICHCALCULATESTHEWATERSOILRETAININGWALLTODISTORTMAINLYHAVING1SEMIEMPIRICALESTIMATE2HORIZONTALLOADPILEMETHODTHEHOLEEXCAVATEDFORBUILDINGFOUNDATIONBOTTOMSURFACEABOVEEARTHPRESSUREJIANHUADAORETAININGWALLPITBOTTOMSECTIONPLACE,BELOWTHEPITBOTTOMTHEWALLREGARDSASTHEPILEHEADHASTHEHORIZONTALFORCEANDTHEMOMENTOFFORCECOMBINEDACTIONCOMPLETEEMBEDMENTPILE,THENACCORDINGTOACCEPTORLEVELLOADFUNCTIONPILEDISPLACEMENTCOMPUTATIONALMETHODCOMPUTATIONPITBOTTOMPLACEWALLHORIZONTALDEPARTUREANDCORNER3INTEGRALEQUATIONLAWTREATSASELASTICALLYTHEFOUNDATIONBEAMTHEWATERSOILRETAININGWALL,AROUNDTHEWALLTHEBOTHSIDESEARTHPRESSUREKNOWN,THEWALLBOTTOMENDISFIXED,THENCARRIESONTHEINTEGRALACCORDINGTOTHEELASTICDEFLECTIONEQUATIONTOSOLVE,OBTAINSTHEWALLDISPLACEMENT4RIGIDPILLARMETHODTHEWALLREGARDSASTHEPITBOTTOMBELOWTHERIGIDPILLAR,BEFORETHEWALL,THESOILBODYREGARDSASASPRING,THENSOLUTIONWALLDISTORTIONINTHEABOVEEACHMETHODAPPLIESUNIVERSALLYBYTHERIGIDPILLARMETHODINTHEPROJECTPRACTICE,ITSHOLEEXCAVATEDFORBUILDINGFOUNDATIONBOTTOMSURFACESPLACEHORIZONTALDEPARTUREY0ANDTHECORNERE0FORMULAIS20300/6824MLHIMLHMYB113642INTHEFORMULAWEL2/00/BWEBELOWPITBOTTOMPARTOFACTIVETHRUSTOFEARTH,EEALLSH0LSWALLBOTTOMSURFACEFRICTIONMAYTAKEBSUL,ISTHESHEARINGSTRENGTHOFNOTTODRAINWATERFORTHEEARTHIBWALLBOTTOMSECTIONMOMENTOFINERTIA,12/4IBHHOLEEXCAVATEDFORBUILDINGFOUNDATIONDEPTH,LTHEPILEINLAYSTHESOLIDDEPTH。THEWALLGOESAGAINSTTHEDISPLACEMENT0HYREGARDINGCOMMONWATERSOILBUILDINGENCLOSURE,IFWANTSTHEWALLTOGOAGAINSTTHEDISPLACEMENTTOCONTROLIN80MM,SUGGESTEDTHATTHEWHOLESTABLESAFETYFACTORK125,ANTISTICKSOUTTHESTABLESAFETYFACTORK150,ANTISLIPPINGSTABLESAFETYFACTORK120,THEIMPROVEMENTANTITILTSTHESTABLESAFETYFACTORKO115USUALLYADOPTSTHEMEASUREENLARGESTHERETAININGWALLWIDTH,ALTHOUGHCANREDUCETHEHORIZONTALDEPARTURETOHAVECERTAINEFFECT,BUTTHEEFFECTIVEMEASURESHOULDSOLVESTHEGROUNDSUPPORTINGCAPACITYPROBLEMIFBEFORETHEWALLTHEPITSUBSOILWITHTHEPRESSURENOTETHICKLIQUIDREINFORCEMENT,INCREASESTHERETAININGWALLBEINGBURIEDDEPTH,FALLSASFARASPOSSIBLETHEWALLBASEONTHEGOODSOILLAYERSUPERIORMEASURE,CANREDUCETHEHORIZONTALDEPARTUREEFFECTIVELY34CONSTRUCTIONQUALITYQUESTIONTHEPILESHAFTWATERSOILISTHECEMENTMORTARPOWDERANDTHEFOUNDATIONSOILAGITATIONNATURALASPECTSANDSOONFOUNDATIONSOILSNATURE,CEMENTMORTARMIXTURERATIO,RABBLINGMECHANISMPERFORMANCEANDCRAFTWILLAFFECTTHEPILEQUALITYINTENSITYANDUNIFORMITYITSKEYLIESINEACHPILETOHAVETHEENOUGHGUNITEPOWDERTHEQUANTITYASWELLASTHEAGITATIONLEVELOFUNIFORMITYTHISBESIDESMACHINESANDTOOLSQUESTION,BUTMUSTMANAGETHEPILEOPERATIONSTRICTLYGUARDSTHETEXTUREOFSOILWITHSTANDINGLATERALLOADWHENASHOLEEXCAVATEDFORBUILDINGFOUNDATION,THEPILESHAFTCANNOTASSUMELAYERED,CANNOTHAVETHEBREAK,ANDNEARBYTHEPITBOTTOMANDSOONSTRESSMOSTMAINPOINTINCREASESTHECEMENTTOMIXTHEQUANTITYSUITABLYTHENEIGHBORINGPILESHOULDJOINGOOD,GUARANTEESITSINTEGRITYINTHECONSTRUCTIONTOCAUSETHEWATERSOILAGITATIONPILECONTINUOUSLY,EVENANDTHEINTENSITYMUSTSATISFYTHEDESIGNREQUIREMENTS,SHOULDCARRYONTHEFOLLOWINGWORK1THEINDOORDETERMINATIONWATERSOILBRIQUETTEINTENSITY,BYDETERMINEDTHATREACHESTHECEMENTWHICHTHEDESIGNINTENSITYNEEDSTOMIXINTHEQUANTITY,THECEMENTSTRENGTHANDSOON2WHENFIELDMIX,MUSTCONTROLTHEPUMPPRESSURE,GENERALLYMAYTAKE0507MPATHEPUMPPRESSUREISSOMEWHATLOW,THEPILEBODYMIDDLECEMENTCONTENTISHIGHERTHANTHEEDGE,PRESENTSTHECONCENTRICSTRUCTURE,REDUCESTHEPILEBODYDIAMETERCROSSESGAOYOUNOTTOBEUNSTABLE,THEPILEREALIZEDTHATPRESENTSTHENONUNIFORMCEMENTCLAYLUMPBLOCK,THESUPPORTINGCAPACITYREDUCESTHEPUMPPRESSURERISESSUDDENLY,AFTERORELEVATES,CONTINUESNOTTOFALL,WILLCAUSETHEPULVERIZERJAMMING,WILLCAUSEBREAKSTHETHICKLIQUID,WILLCAUSETHEAGITATIONPILESHAFTTOCLAMPTHEPUTTYLEVEL,WILLCAUSETHEPILESHAFTBREAKTHEPILEBODYMUDJACKINGREQUESTSTOFORMACOHERENTWHOLE,DONOTINTERRUPT,EACHPILESUITABLEATTIRETHICKLIQUIDTIMEANDSPURTSSTIRSCOMPLETESTHEREQUESTCONSTRUCTSCONTINUOUSLY,THEPILEJOININGALTERNATIONOVERLAPPINGCONSTRUCTION,THENEIGHBORINGTWOPILECONSTRUCTIONGAPDONOTSURPASSFOR12HOURSIFSURPASSES,THEJOININGQUALITYDOESNOTHAVETHEGUARANTEE,SHOULDADOPTMIDDLETWOPILESADDSTHEPILERECOVERY3THEAGITATIONPILESMACHINEWINDINGSPEEDANDTHEROTATIONALSPEEDREQUESTCUTTOPIECESASFARASPOSSIBLETHEFOUNDATIONSOILANDMIXUPEVENLYFULLYTHECEMENTMORTARANDTHEEARTHSTIRSTHELEVELOFUNIFORMITYTOBEVERYBIGTOTHEPILESHAFTINFLUENCE,WHENMIXERSROTATIONALSPEEDISCERTAIN,THEAGITATIONNUMBEROFTIMESWITHTHEUNIFORMITYWHICHMIXESUP,DIRECTLYWITHWINDINGSPEEDRELATED,GENERALLYTAKEDOESNOTSURPASS0810M/SUITABLYTHEMINUTEAS4THECONSTRUCTIONPROCESSSTOPSTHETHICKLIQUIDFORSOMEREASON,TOSTOPSSUITABLYTHEMIXERSUBMERSIONTHICKLIQUIDNEXT50MM,RESTORESSTIRSTHEPROMOTIONAGAINFORTHETHICKLIQUID5THEPILESHAFTVERTICALITYDEVIATIONDONOTSURPASS15,THEPILEPOSITIONDEVIATIONDONOTBEBIGGERTHAN50MM6AFTERMAKINGTHEPILE,SHOULDCARRYONTHEQUALITYDETECTION,ITSMETHODHASTHEFACILESOUNDINGLAW,THESTATICSOUNDINGLAW,THESIGNTOPASSTHROUGHTHELAW,THEDRILLINGSAMPLINGMETHOD,TOMOVEMEASURESANDSOONMETHODS4SUMMARYALONGWITHTHEURBANDERGROUNDSPACESDEVELOPMENTUSE,THEWATERSOILAGITATIONPILETAKESTHEHOLEEXCAVATEDFORBUILDINGFOUNDATIONONEECONOMICALSUPPORTSANDPROTECTIONSMETHOD,THEAPPLICATIONISGETTINGMOREANDMOREWIDESPREAD,SPECIALLYINCUTTINGDEPTHNOTBIGANDSOFTSOILAREABUTTHEWATERSOILAGITATIONPILESERVESASTHEHOLEEXCAVATEDFORBUILDINGFOUNDATIONSUPPORTSANDPROTECTIONS,BECAUSEITSELFEXISTSFLAW,IFDOESNOTPERFORMTOSOLVE,WILLRELATETHEENTIRESUPPORTSANDPROTECTIONSTHESUCCESSORFAILURE,SERIOUSPOSSIBLYCAUSESTHEACCIDENT,MUSTBRINGTOTHEATTENTIONUSESINTHEHOLEEXCAVATEDFORBUILDINGFOUNDATIONSUPPORTSANDPROTECTIONSTHEWATERSOILPILE,SHOULDEARNESTCHECKINGCALCULATIONITSANTIBOOKLET,THECOMPRESSIVESTRENGTHANDTHELATERALDISPLACEMENTSHOULDTAKEAUNIFIEDWHOLETHEHOLEEXCAVATEDFORBUILDINGFOUNDATIONSUPPORTSANDPROTECTIONSSTRUCTUREANDTHEHOLEEXCAVATEDFORBUILDINGFOUNDATIONCONSTRUCTIONANDENVIRONMENTSPROTECTIONTOCARRYONTHEDESIGNANDTHECONSTRUCTION,ANDCARRIESONTHECLOSECONTROLINTHEIMPLEMENTATIONPROCESSTOBECOORDINATED,ANDTAKESTHEEFFECTIVEACTIONACCORDINGTOTHEACTUALSITUATION,DISPLAYSTHEWATERSOILAGITATIONPILECONSTRUCTIONCOSTTOREDUCE,OUTSIDEFULLYTHETIMESHORTTHISSUPERIORITY,BUTMUSTGUARANTEETHEHOLEEXCAVATEDFORBUILDINGFOUNDATIONANDTHEENVIRONMENTSECURITYREFERENCE1JGJ12099CONSTRUCTIONHOLEEXCAVATEDFORBUILDINGFOUNDATIONSUPPORTSANDPROTECTIONSTECHNICALSCHEDULESBEIJINGCHINABUILDINGINDUSTRYPUBLISHINGHOUSE,19992LIUJIANHANG,HOUXUEYUANHOLEEXCAVATEDFORBUILDINGFOUNDATIONENGINEERINGMANUALMBEIJINGCHINABUILDINGINDUSTRYPUBLISHINGHOUSE,19973NINGPOURBANARCHITECTUREDESIGNRESEARCHINSTITUTEANDSOONTHENINGPOSOFTSOILDEEPHOLEEXCAVATEDFORBUILDINGFOUNDATIONSUPPORTSANDPROTECTIONSDESIGNANDCONSTRUCTTHETEMPORARYTECHNIQUETOSTIPULATETHESNINGBONINGBOPUBLISHINGHOUSE,19984GONGXIAONAANDSOONINDEPTHPUDDLEPROCESSDESIGNANDCONSTRUCTIONINDEPTHPUDDLEPROCESSDESIGN,CONSTRUCTIONEXPERIENCEMEETINGCOLLECTIONMBEIJINGCHINESERAILROADPUBLISHINGHOUSE,1993水泥土搅拌桩在基坑支护应用中存在问题的探讨摘要水泥土搅拌桩用作基坑支护,因其本身存在的缺陷,如果不加以解决,将关系到整个支护的成败,严重的可能引起事故,必须引起重视。关键词基坑支护;水泥土搅拌桩;1前言二站后,美国首先研制成功深层搅拌法,我国于1977年引进,1980年正式应用于工程实践,经二十多年开发、推广,在我国的软土地区得到广泛应用,发展迅速。水泥土搅拌桩用于深基坑支护作用的连续壁,又称SMW工法。我国最早由宝钢工程引进这一工法作为围护结构,之后在全国推广。这种工法施工干扰少、对软地基适应性强,并具有构造简单、对周围建筑影响小、工期短、造价低、环境污染小等优点,且可作止水墙又可作为挡土墙,因此深受欢迎。2水泥土搅拌桩概述水泥土搅拌桩是通过相邻水泥土桩搭接而成,采用水泥作为固化剂,通过专用搅拌机械,将软土和水泥强制搅拌形成水泥土,利用水泥与软土之间所产生一系列物理、化学作用,使水泥土强度增长,成为水泥土桩,硬化后形成具有一定强度的水泥壁状挡墙。3存在问题及改进措施然而,目前由于水泥土搅拌桩的施工质量参差不齐,差异很大,有些影响到基坑的安全,造成了一些事故。因此,本文通过分析水泥土搅拌桩工法在基坑支护应用中存在的问题,探讨此技术的应用研究的必要性及其经济价值,杜绝事故发生。31适应性问题在搅拌桩施工过程中,往往会碰到搅拌到一定深度后,就不能继续钻进的问题,这就须从搅拌桩这种工法的适用范围究其原因。任何一种软土地基处理方法只能在一定范围内适用,即技术上可行性与经济上合理性。在方案选择时,应从具体条件出发,结合各种工法的特点,选择最合适的工艺。同样,水泥土搅拌桩也存在适应问题311土质条件适用性水泥土搅拌桩一般适用于淤泥、淤泥质土、粉土和含水量较高且地基承载力标准值不大于120KPA的粘性土等地基。当用于泥炭土或地下水具有侵蚀性时,宜通过试验确定其适用性,冬季施工时应注意负温度对处理效果的影响。312场地与环境适用性水泥土搅拌桩施工时无振动、无噪音、不排污、不侧向挤土。对拟建场地周围建筑物密集、人口聚居、有各种地下管道的地方尤为合适。313工程类型适用性因其强度不高,作为基坑开挖支护的挡土结构时,限制了支护深度,一般不能超过46M。32水泥土强度问题水泥土的强度与土的性质、水泥掺量、施工质量等有关,土质越粘、强度越低;土中有机质对强度也有很大的影响。根据试验分析,淤泥质土中,当水泥掺量小于12时,其抗压强度不超过08MPA,甚至更低。还有一个值得注意的现象,水泥土桩用作支护结构时,在开挖出来之前,其强度很低,一旦暴露在空气中,强度迅速增长。因此最适宜的质量鉴定方法应是岩芯取样,或用实际土样制备成试块后置于水下养护。在通常粘性土拌和的水泥土,容许压应力06MPA,容许剪应力,容许40CACAA50拉应力。但应满足。水泥土的强度不高限制了其支护高度。必CAA150MP2须重视施工质量,应采用慢速推进,住复两次以上的搅拌方式。适当加大水泥土掺入比并加入适量外掺剂,可有效地提高桩身强度。现基坑支护中应用较多的是在经充分搅拌后的水泥土搅拌桩中插入毛竹、H型钢或其他型材插入搅拌桩体内,提高水泥土搅拌桩的受拉强度,从而更好地起到支护作用。33水平位移控制问题用作基坑支护就必须控制基坑变形位移,防止变形过大而影响周围环境、工程桩基及地下室施工。应根据安全等级和现场实际条件,通过合理的设计确定基坑容许的位移控制值,从而在施工过程中加以防范。目前用于计算水泥土挡墙变形的方法主要有1半经验估算;2水平荷载桩方法将基坑底面以上的土压力简化到挡墙坑底截面处,坑底以下墙体视为桩头有水平力和力矩共同作用的完全埋置桩,然后按承受水平荷载作用桩的位移计算方法计算坑底处墙体的水平位移和转角;3积分方程法将水泥土挡墙当作弹性地基梁,墙体前后两侧土压力已知,墙

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