控制建筑桩基施工的隐患问题

'http://www.tastjx.comhttp://www.sdminlejx.cnhttp://www.cnftkyfj.comhttp://www.qiangliyy.cn控制建筑桩基施工的隐患问题桩基施工的技术细节Technicaldetailsfortheconstructionofthepilefoundation　　（1）施工时，如果桩身内部的混凝土强度与预先设计的强度相符时，应该将桩静置而且经过蒸汽的养护之后方可施工；在进行沉桩的施工时，利用经纬仪严格的测量，使桩应该保持垂直，误差不超过0.5%，因为偏差较大时，会导致桩身容易开裂。(1)theconstruction,iftheconcretestrengthofpilebodyinternalandthestrengthofthedesigninadvanceisconsistent,shouldwillpilestaticbuyandaftersteamcuringbeforeconstruction;Usetheodoliteinduringpiledrivingconstruction,thestrictmeasure,makethepileshouldbekeptvertical,errorisnotmorethan0.5%,becauseofthedeviationisbigger,canleadtopilebodyiseasytocrack.　　（2） http://www.tastjx.comhttp://www.sdminlejx.cnhttp://www.cnftkyfj.comhttp://www.qiangliyy.cn进行接桩的操作施工时，接桩通常采用钢端板焊接的方式，在桩身离地面一米的距离时即可进行焊接、接桩时要时刻观察两节桩身的衔接情况，保证圆角和直角相互正对，在桩顶清理干净之后要进行定位板固定，接着再将上段的桩吊放在下段桩的端板上，利用定位板将上下段的桩接直，如果在两段桩的衔接处有空隙，要利用锲形的铁片加以焊接固定。接头处坡口槽电焊应分三层对称进行，焊接时应减小焊接变形，焊缝连续饱满；焊后清除焊渣，检查焊缝饱满程度焊接完成后应等接头温度与周围环境温差在100以内才能沉桩，一般情况下静压桩等候6分钟锤击桩等候8分钟为宜，不得用水淋等方式快速冷却。(2)receivingtheoperationofthepileconstruction,thepileextensionusuallyadoptssteelendplateweldingmethod,thepilebodyfromtheground1meterdistancefromtheweldingcanbemadetoobservingtwopilebody,pileextensionofcohesion,ensureroundedcornersandanglestoeachother,atthetopofthepilehasbeenclearedforpositioningplateisfixed,thenwillbeunderthepileofhangingonintheuppersectionofpileendplate,usingthepositioningplatewillbestraightfromtoptobottomofthepile,ifthereisagapintwopilesatthe http://www.tastjx.comhttp://www.sdminlejx.cnhttp://www.cnftkyfj.comhttp://www.qiangliyy.cnconnecting,totakeadvantageofthisformofplatetoweld.Groovegrooveweldedjointshouldbethreelayersofsymmetry,shouldreduceweldingdistortionduringwelding,weldcontinuousfull;Cleaningweldingslagafterwelding,inspectionofweldfulldegreeaftercompletionofweldingjointshallbesuchastemperatureandtheambienttemperaturewithinthe100topiledriving,generallystaticpressurepilehammerfor6minuteswaitingfor8minutesadvisable,notfastcoolingwaterdrench,etc.　　（3）在桩冒和送桩器的选择上，要保持外形上的相互匹配，而且在强度和刚度等的选取上也一定要合格，桩冒和送桩器的下端应该采用开孔的方式来加强桩内部同外界的互通性能，乳化液泵站尽量使得每次沉桩的操作都一次到底，避免中间的出现的短暂性停歇；在沉桩的过程中，如果混凝土输送泵出现贯入度不正常，桩身出现略微的偏差或位移时，为了避免桩身或者桩顶的损坏应立即停止沉桩，通过分析出现这种情况的原因并且加以解决，接着方可继续施工。(3)onthechoiceofpileriskandimplement, http://www.tastjx.comhttp://www.sdminlejx.cnhttp://www.cnftkyfj.comhttp://www.qiangliyy.cntokeeptheshapematchingeachother,andinthestrengthandstiffness,etc.Alsomustbequalified,theselectionofpileriskandapileofpilebottomshouldadoptthewayofopeningtostrengtheninternalandexternalcommunicationperformance,trytomakeeverypiledrivingoperationsexactlyatatime,toavoidtheemergenceofthemiddleofthetransient;Intheprocessofpiledriving,ifthereisapenetrationisnotnormal,pilebodyappearedslightlydeviationordisplacement,inordertoavoidthedamageofpileorpileonthetopofthepiledriving,shouldimmediatelystopbyanalysisthereasonandsolvethem,thisisthecasethenmaycontinuetoconstruction.　　（4）对于空心桩一般不进行截桩的操作，如果遇到特殊的情况必须要截桩时，通风除尘设备应该采用机械分割的方法将无需截掉的那部分桩身加以固定，然后再沿着钢箍的上边缘进行切割，钢箍绝对不可以利用人力进行强行的截除，可以利用气割法进行切割。(4)fortheoperationofthehollowpileis http://www.tastjx.comhttp://www.sdminlejx.cnhttp://www.cnftkyfj.comhttp://www.qiangliyy.cngenerallynottocut,ifthereareanyspecialcasesmustbecutpile,shouldadoptthemethodofmechanicalsegmentationwillnotneedtocutoffthepartofthepilebodyarefixed,andthenalongtheupperedgeofthehoopsforcutting,hoopsisabsolutelycan"tusemanpowertoforciblycutting,canusetheflamecuttingmethodforcutting.1、单桩承载力低于设计要求的常见原因1,acommoncauseofsinglepilebearingcapacityislowerthanthedesignrequirements　　a.桩沉人深度不足。b.桩端未进入设计规定的持力层,但桩深已达设计值。c.最终贯人度过大。d.其他,诸如桩倾斜过大、断裂等原因导致单桩承载力下降。e.勘察报告所提供的地层剖面、地基承载力等有关数据与实际情况不符。A.peoplepilesinkingdepth.B.bearinglayer,pileendisnotdesignbutthepiledepthhasreacheditsdesignvalue.C.penetrationpeoplespendbigintheend.D.other,suchaspiletiltistoolarge,suchasfracturereasonsledtothedecreaseofthesinglepile http://www.tastjx.comhttp://www.sdminlejx.cnhttp://www.cnftkyfj.comhttp://www.qiangliyy.cnbearingcapacity.E.stratigraphicprofile,foundationbearingcapacityprovidedbythesurveyreportandrelateddatadonottallywiththeactualsituation.　　2、桩倾斜过大的常见原因2,acommoncauseofpiletiltistoolarge　　a.预制桩质量差,其中桩顶面倾斜和桩尖位置不正或变形,最易造成桩倾斜。b.桩机安装不正,桩架与地面不垂直。c.桩锤、桩帽、桩身的中心线不重合,产生锤击偏心。d.桩端遇石子或坚硬的障碍物。e.桩距过小,打桩顺序不当而产生强烈的挤土效应。f.基坑土方开挖不当。A.poorqualityofprecastpile,thepiletopsurfacetiltandpiletipmalpositionordeformation,themosteasilycausepiletilt.B.pilemachineinstallationisnotstraight,notverticalwiththeground.C.hammerpile,pilecap,pileshaftcenterlineisnotcoincidence,eccentrichammeringisproduced.D.pileendstonesorsolidbarrier.E.thepilespacingistoosmall,drivingstrongcompactioneffectresultingfromtheimproper http://www.tastjx.comhttp://www.sdminlejx.cnhttp://www.cnftkyfj.comhttp://www.qiangliyy.cnorder.F.improperexcavationearthworkexcavation.　　3、出现断桩的常见原因3,acommoncauseofbrokenpile　　除了桩倾斜过大可能产生桩断裂外：其他原因还有三种:a桩堆放、起吊、运输的液压升降机平台支点或吊点位置不当。b沉桩过程中,桩身弯曲过大而断裂。如桩制作质量造成的弯曲,或桩细长又遇到较硬土层时,锤击产生的弯曲等。锤击次数过多，如有的设计要求的桩锤击过重,设计贯入度过小,以致于施工时,锤击过度而导致桩断裂。Besidespiletilttoolargemayproducefracture,otherreasonsarethree:apilepileup,lifting,transportationsupport,orimproperliftingpointlocation.Bintheprocessofpile,pilebodyexcessivebendingandfracture.Curvessuchasthepilequality,slenderagainmeetahardsoillayer,orpilehammerproducedbybending,etc.Amountsofhammer,ifsomeofpilehammerofthedesignrequirements,designpenetrationthroughsmall,sothattheconstruction,thepilehammerand http://www.tastjx.comhttp://www.sdminlejx.cnhttp://www.cnftkyfj.comhttp://www.qiangliyy.cncausefracture.　　4、桩接头断离的常见原因4,pileconnectionbrokenawayfromthecommoncause　　设计桩较长时,因施工工艺的需要,桩分段预制,分段沉人,各段之间常用钢制焊接连接件做桩接头。其原因,还有上、下节桩中心线不重合;桩接头施工质量差,如焊缝尺寸不足等原因。Designwhenthepileislonger,becauseoftheneedsoftheconstructionprocess,theprefabricatedpilesection,subsectionsink,commonlyusedsteelweldedfittingstodopilejointbetweenparagraphs.Itsreason,andthecenterlineoftheupperandlowersectionpiledoesnotoverlap;Jointconstructionofpoorquality,suchasinsufficientweldsize,etc.　　5、桩位偏差过大的常见原因5,acommoncauseofpilelocationdeviationistoolarge　　测量放线差错;沉桩工艺不良,如桩身倾斜造成竣工桩位出现较大的偏差, http://www.tastjx.comhttp://www.sdminlejx.cnhttp://www.cnftkyfj.comhttp://www.qiangliyy.cn打桩过程中,，施工单位切忌自行处理,必须报监理、业主,然后会同设计、勘察等相关部门分析、研究,作出正确处理方案，由设计部门出具修改设计通知。Measuringunreelingerrors;Pile-sinkingprocessfailure,suchaspiletiltofpilecompletionappearlargedeviation,intheprocessofpiledriving,,avoidbyallmeanstodealwithconstructionunit,supervision,mustbesubmittedtotheowner,andthen,inconjunctionwiththedesign,analysis,research,investigationandotherrelateddepartmenttomakecorrecttreatmentscheme,themodifieddesignnoticeissuedbydesigndepartment.'