《安全員》課件-02基坑支護(hù)

《安全員》TheSecurity第二節(jié)基坑支護(hù)Section2FoundationPitSupport由于作為支護(hù)結(jié)構(gòu)的擋土結(jié)構(gòu)插入深度不夠，或支撐位置不當(dāng)，或支撐與圍檁系統(tǒng)的結(jié)合不牢等原因，造成擋土結(jié)構(gòu)位移過(guò)大的前傾或后仰，甚至擋土結(jié)構(gòu)倒塌，導(dǎo)致坑外土體大滑坡，支護(hù)結(jié)構(gòu)系統(tǒng)整體失穩(wěn)破壞。Asaresultoftheretainingstructureasasupportstructureinsertedintothedepthisnotenough,orsupportpositionisnotappropriate,orsupportandpurlinsystemisnotfirmlycombined,etc.,resultingintheretainingstructuredisplacementtoolargeforwardorbackward,orevenretainingstructurecollapse,resultinginalargesoilslideoutsidethepit,thesupportstructuresystemasawholedestabilizationdamage.一、支護(hù)結(jié)構(gòu)破壞的主要形式I.Themainformsofdamagetothesupportstructure1．整體失穩(wěn)1.Overallinstability在軟弱的粘性土層中開(kāi)挖基坑，當(dāng)基坑內(nèi)的土體不斷開(kāi)挖，挖深增大，荷載亦增加。當(dāng)擋土結(jié)構(gòu)人土深度不足，則會(huì)使基坑內(nèi)土體大量隆起，基坑外土體過(guò)量沉陷，支撐系統(tǒng)應(yīng)力陡增，導(dǎo)致支護(hù)結(jié)構(gòu)整體失穩(wěn)破壞。Whenapitisexcavatedinasoftclaysoillayer,thesoilinthepitiscontinuouslyexcavated,theexcavationdepthincreasesandtheloadalsoincreases.Whentheretainingstructureisnotdeepenough,itwillcausealargeamountofsoilheavinginthepit,excessivesinkingofthesoiloutsidethepitandasteepincreaseinthestressofthesupportsystem,resultingintheoverallinstabilityofthesupportstructure.一、支護(hù)結(jié)構(gòu)破壞的主要形式I.Themainformsofdamagetothesupportstructure2．基坑隆起2.Pituplift含水砂質(zhì)粉土層或粉質(zhì)砂土層中的基坑支護(hù)結(jié)構(gòu)，在基坑開(kāi)挖過(guò)程中，擋土墻內(nèi)外形成水頭差。當(dāng)動(dòng)水壓力的滲流速度超過(guò)臨界流速或水力坡度超過(guò)臨界坡度時(shí)，就會(huì)引起管涌及流砂現(xiàn)象。基坑底部和墻體外面大量的泥砂隨地下水涌入基坑，導(dǎo)致坑外地面坍陷，嚴(yán)重時(shí)使墻體產(chǎn)生過(guò)大位移，引起整個(gè)支護(hù)體系崩坍。Water-bearingsandychalklayerorchalkysandysoillayerinthefoundationsupportstructure,intheprocessofexcavationofthefoundation,theformationofheaddifferenceinsideandoutsidetheretainingwall.Whentheseepagerateofdynamicwaterpressureexceedsthecriticalflowrateorthehydraulicgradientexceedsthecriticalgradient,itwillcausethephenomenonofpipesurgeandsandflow.Alargeamountofmudandsandfromthebottomofthepitandtheoutsideofthewallgushesintothepitwiththegroundwater,causingthegroundoutsidethepittocollapseand,inseriouscases,causingthewalltoproduceexcessivedisplacementandcausingthewholesupportsystemtocollapse.一、支護(hù)結(jié)構(gòu)破壞的主要形式I.Themainformsofdamagetothesupportstructure3．管涌及流砂3.Pipesurgeandsandflow當(dāng)支撐設(shè)計(jì)時(shí)，由于計(jì)算受力不準(zhǔn)確，或套用的規(guī)范不對(duì)，考慮的安全系數(shù)有誤，亦或施工質(zhì)量低劣，未能滿足設(shè)計(jì)要求，一旦基坑土方開(kāi)挖，在較大的側(cè)向土壓力作用下，發(fā)生支撐折斷破壞，或嚴(yán)重壓屈，引起墻體變形過(guò)大或破壞，導(dǎo)致整個(gè)支護(hù)結(jié)構(gòu)破壞。Whenthedesignofthesupport,duetoinaccuratecalculationoftheforce,ortheapplicationofthecodeisnotcorrect,considerthesafetyfactoriswrong,orconstructionqualityispoor,failedtomeetthedesignrequirements,oncetheexcavation,inthelargerlateralsoilpressure,thesupportfracturedamage,orseriouspressureflexure,causingexcessivedeformationordamagetothewall,resultinginthedestructionoftheentiresupportstructure.一、支護(hù)結(jié)構(gòu)破壞的主要形式I.Themainformsofdamagetothesupportstructure4．支撐強(qiáng)度不足折斷或壓屈4.Insufficientstrengthofthesupportbreakageorcompressionbending（1）基坑（槽）、邊坡、基礎(chǔ)樁、模板和臨時(shí)建筑作業(yè)前，應(yīng)按設(shè)計(jì)單位要求，根據(jù)地質(zhì)情況、施工工藝、作業(yè)條件及周邊環(huán)境編制施工方案。單位分管負(fù)責(zé)人審批簽字，項(xiàng)目負(fù)責(zé)人組織驗(yàn)收，經(jīng)驗(yàn)收合格簽字后，方可作業(yè)。

(1)Foundationpits(slots),slopes,foundationpiles,formworkandtemporaryconstructionoperationsbefore,accordingtotherequirementsofthedesignunit,accordingtothegeologicalsituation,constructiontechniques,operatingconditionsandthesurroundingenvironmenttoprepareconstructionplans.Thepersoninchargeoftheunitshallapproveandsign,andthepersoninchargeoftheprojectshallorganiseacceptance,andshallonlyoperateafterpassingtheacceptanceandsigning.

二、基坑支護(hù)安全技術(shù)要求II.Technicalrequirementsforpitsupportsafety（2）土方開(kāi)挖前，應(yīng)確認(rèn)地下管線的埋置深度、位置及防護(hù)要求后，制定防護(hù)措施，經(jīng)項(xiàng)目分管負(fù)責(zé)人審批簽字后，方可作業(yè)，土方開(kāi)挖時(shí)，施工單位應(yīng)對(duì)相鄰建筑物、道路的沉降和位移情況進(jìn)行觀測(cè)。(2)Beforeexcavation,theburialdepth,locationandprotectionrequirementsofundergroundpipelinesshouldbeconfirmed,andprotectivemeasuresshouldbeformulatedandapprovedandsignedbythepersoninchargeoftheprojectbeforeoperation,andtheconstructionunitshouldobservethesettlementanddisplacementofadjacentbuildingsandroadsduringexcavation.

二、基坑支護(hù)安全技術(shù)要求II.Technicalrequirementsforpitsupportsafety（3）項(xiàng)目部應(yīng)作好施工區(qū)域內(nèi)臨時(shí)排水系統(tǒng)規(guī)劃，臨時(shí)排水不得破壞相鄰建（構(gòu)）筑物的地基和挖、填土方的邊坡。在地形、地質(zhì)條件復(fù)雜，可能發(fā)生滑坡、坍塌的地段挖方時(shí)，應(yīng)由設(shè)計(jì)單位確定排水方案。場(chǎng)地周?chē)霈F(xiàn)地表水匯流、排瀉或地下水管滲漏時(shí)，施工單位應(yīng)組織排水，對(duì)基坑采取保護(hù)措施。開(kāi)挖低于地下水位的基坑（槽）、邊坡和基礎(chǔ)樁時(shí)，施工單位應(yīng)合理選用降水措施降低地下水位。

(3)Theprojectdepartmentshallmakegoodplanningforthetemporarydrainagesystemintheconstructionarea,andthetemporarydrainageshallnotdamagethefoundationsofadjacentbuildings(structures)andtheslopesofexcavatedandfilledearth.Whenexcavatinginlotswithcomplexterrainandgeologicalconditions,wherelandslidesandcollapsesmayoccur,thedrainageplanshallbedeterminedbythedesignunit.Intheeventofsurfacewaterconfluence,drainageorleakagefromundergroundwaterpipesaroundthesite,theconstructionunitshouldorganisedrainageandtakeprotectivemeasuresforthefoundationpit.Whenexcavatingpits(slots),slopesandfoundationpilesbelowthegroundwaterlevel,theconstructionunitshouldreasonablychoosetolowerthegroundwaterlevelbymeansofprecipitationmeasures.

二、基坑支護(hù)安全技術(shù)要求II.Technicalrequirementsforpitsupportsafety（4）基坑（槽）、邊坡設(shè)置坑（槽）壁支撐時(shí)，項(xiàng)目部應(yīng)根據(jù)開(kāi)挖深度、土質(zhì)條件、地下水位、施工方法及相鄰建（構(gòu)）筑物等情況設(shè)計(jì)支撐。拆除支撐時(shí)應(yīng)按基坑（槽）回填順序自下而上逐層拆除，隨拆隨填，防止邊坡塌方或相鄰建（構(gòu)）筑物產(chǎn)生破壞，必要時(shí)采取加固措施。

(4)foundationpit(slot),theslopesetpit(slot)wallsupport,theprojectdepartmentshouldbedesignedaccordingtotheexcavationdepth,soilconditions,groundwaterlevel,constructionmethodsandadjacentbuildings(structures)andothercircumstancessupport.Whenremovingthesupportshouldbeinaccordancewiththefoundationpit(slot)backfillorderfromthebottomuplayerbylayerremoval,withthedemolitionoffilling,topreventtheslopecollapseoradjacentbuilding(structure)toproducedamage,ifnecessarytotakereinforcementmeasures.

二、基坑支護(hù)安全技術(shù)要求II.Technicalrequirementsforpitsupportsafety（5）基坑（槽）、邊坡和基礎(chǔ)樁孔邊堆置各類(lèi)建筑材料的，應(yīng)按規(guī)定距離堆置。各類(lèi)施工機(jī)械距基坑（槽）、邊坡和基礎(chǔ)樁孔邊的距離，應(yīng)根據(jù)設(shè)備重量、基坑（槽）、邊坡和基礎(chǔ)樁的支護(hù)、土質(zhì)情況確定，并不得小于1.5m。

(5)Foundationpits(slots),sideslopesandfoundationpileholessidepilesofvarioustypesofconstructionmaterials,shouldbestackedinaccordancewiththeprescribeddistance.Thedistanceofconstructionmachineryfromthefoundationpit(trench),slopeandfoundationpileholeshallbedeterminedaccordingtotheweightoftheequipment,thesupportofthefoundationpit(trench),slopeandfoundationpileandthesoilquality,andshallnotbelessthan1.5m.

二、基坑支護(hù)安全技術(shù)要求II.Technicalrequirementsforpitsupportsafety（6）基坑（槽）作業(yè)時(shí)，項(xiàng)目部應(yīng)在施工方案中確定攀登設(shè)施專用通道，作業(yè)人員不得攀爬模板、腳手架等臨時(shí)設(shè)施。(6)Whenworkinginthefoundationpit(trench),theprojectdepartmentshalldeterminethespecialchannelforclimbingfacilitiesintheconstructionplan,andtheworkersshallnotclimbthetemporaryfacilitiessuchasformworkandscaffolding.（7）機(jī)械開(kāi)挖土方時(shí)，作業(yè)人員不得進(jìn)入機(jī)械作業(yè)范圍內(nèi)進(jìn)行清理或找坡作業(yè)。(7)Whenexcavatingsoilbymachinery,workersshallnotenterthescopeofmachineryoperationforcleaningorslopefindingoperation.

（8）地質(zhì)災(zāi)害易發(fā)區(qū)施工時(shí)，應(yīng)根據(jù)地質(zhì)勘察資料編制施工方案，單位分管負(fù)責(zé)人審批簽字，項(xiàng)目分管負(fù)責(zé)人組織有關(guān)部門(mén)驗(yàn)收，經(jīng)驗(yàn)收合格簽字后，方可作業(yè)。施工時(shí)應(yīng)遵循自上而下的開(kāi)挖順序，嚴(yán)禁先切除坡腳。爆破施工時(shí)，應(yīng)防止爆破震動(dòng)影響邊坡穩(wěn)定。(8)Whenconstructioniscarriedoutingeologicalhazardproneareas,theconstructionplanshallbepreparedaccordingtothegeologicalsurveydata,approvedandsignedbythepersoninchargeoftheunit,andthepersoninchargeoftheprojectshallorganisetherelevantdepartmentsforacceptance,andshallonlyoperateafterpassingtheacceptanceandsigning.Thetop-downexcavationsequenceshouldbefollowedduringconstructionanditisstrictlyforbiddentoexcisethefootoftheslopefirst.Duringblastingconstruction,blastingvibrationshouldbepreventedfromaffectingthestabilityoftheslope.（9）為防止地面水流入基坑（槽）內(nèi)造成邊坡塌方或土體破壞。基坑（槽）開(kāi)挖或回填應(yīng)連續(xù)進(jìn)行，在施工過(guò)程中，應(yīng)隨時(shí)檢查坑（槽）壁的穩(wěn)定情況。

(9)Topreventgroundwaterfromflowingintothefoundationpit(trench)causingslopecollapseorsoildamage.Theexcavationorbackfillingofthepit(trench)shouldbecarriedoutcontinuously,andthestabilityofthepit(trench)wallshouldbecheckedatanytimeduringtheconstructionprocess.

（10）模板作業(yè)時(shí)，應(yīng)對(duì)模板支撐宜采用鋼支撐材料作支撐立柱，不得使用嚴(yán)重銹蝕、變形、斷裂、脫焊、螺栓松動(dòng)的鋼支撐材料和竹材作立柱。支撐立柱基礎(chǔ)應(yīng)牢固，并按設(shè)計(jì)計(jì)算嚴(yán)格控制模板支撐系統(tǒng)的沉降量，支撐立柱基礎(chǔ)應(yīng)牢固，支撐立柱基礎(chǔ)為泥土地面時(shí)，應(yīng)采取排水措施，對(duì)地面平整、夯實(shí)，并加設(shè)滿足支撐承載力要求的墊板后，方可用以支撐立柱，斜支撐立柱應(yīng)牢固拉接，行成整體。(10)Whenworkingwithformwork,itisadvisabletousesteelsupportmaterialsforsupportingcolumns,andnottousesteelsupportmaterialsandbambooforcolumnsthatareseriouslycorroded,deformed,fractured,unweldedorwithloosebolts.Supportcolumnfoundationshouldbefirm,andaccordingtothedesigncalculationstrictlycontrolthesettlementoftheformworksupportsystem,supportcolumnfoundationshouldbefirm,supportcolumnfoundationforthesoilground,shouldtakedrainagemeasures,thegroundleveling,ramming,andaddtomeettherequirementsofthebearingcapacityofthesupportmat,canbeusedtosupportthecolumn,diagonalsupportcolumnshouldbefirmlyconnected,formingawhole.（11）基坑（槽）、邊坡和基礎(chǔ)樁施工及模板作業(yè)時(shí)，應(yīng)指定專人指揮、監(jiān)護(hù)，出現(xiàn)位移、開(kāi)裂及滲漏時(shí)，應(yīng)立即停止施工，將作業(yè)人員撤離作業(yè)現(xiàn)場(chǎng)，待險(xiǎn)情排除后，方可作業(yè)。

(11)Foundationpits(trench),slopesandfoundationpileconstructionandformworkoperations,shouldbedesignatedtodirect,supervision,displacement,crackingandleakage,shouldimmediatelystopconstruction,theoperatorwillbeevacuatedfromtheworksite,untilthedangerisremoved,beforetheoperation.

（12）樓面、屋面堆放建筑材料、模板、施工機(jī)具或其他物料時(shí)，施工單位應(yīng)嚴(yán)格控制數(shù)量、重量，防止超載。堆放婁量較多時(shí)，應(yīng)進(jìn)行荷載計(jì)算，并對(duì)樓面、屋面進(jìn)行加固。

(12)floor,roofstackingbuildingmaterials,formwork,constructionmachineryorothermaterials,constructionunitsshouldstrictlycontrolthenumber,weight,topreventoverloading.WhenstackingLouamountismore,loadcalculationshouldbecarriedoutandthefloorandroofshouldbereinforced.

（13）項(xiàng)目部應(yīng)按地質(zhì)資料和設(shè)計(jì)規(guī)范，確定臨時(shí)建筑和基礎(chǔ)型式和平面布局，并按施工規(guī)范時(shí)行施工，施工現(xiàn)場(chǎng)臨時(shí)建筑與建筑材料的間距應(yīng)符合技術(shù)標(biāo)準(zhǔn)。

(13)Theprojectdepartmentshoulddeterminethetemporarybuildingandfoundationtypeandplanlayoutaccordingtothegeologicaldataanddesignspecifications,andaccordingtotheconstructionspecificationswhentheconstruction,thespacingoftemporarybuildingsandconstructionmaterialsattheconstructionsiteshouldbeinlinewithtechnicalstandards.

（14）臨時(shí)建筑外側(cè)為街道或行人通道時(shí)，應(yīng)采取加固措施，禁止在施工圍墻墻體上方或緊靠施工圍墻架設(shè)廣告或宣傳標(biāo)牌。施工圍墻外側(cè)應(yīng)有禁止人群停留、聚集和堆砌土方、貨物等的警告。

(14)Wheretheoutsideofatemporarybuildingisastreetorpedestrianaccess,reinforcementmeasuresshallbetakenandtheerectionofadvertisingorpromotionalsignsaboveorimmediatelyadjacenttotheconstructionfencewallshallbeprohibited.Thereshouldbeawarningontheoutsideoftheconstructionfencethatcrowdsareforbiddentostay,gatherandpileupearth,goods,etc.

（15）施工現(xiàn)場(chǎng)使用的組裝式活動(dòng)房屋應(yīng)有產(chǎn)品合格證，在組裝后進(jìn)行驗(yàn)收，經(jīng)驗(yàn)收全權(quán)簽字后，方能使用。對(duì)搭設(shè)在空曠、山腳等處的活動(dòng)房應(yīng)采取防風(fēng)、防洪和防暴雨等措施。(15)Theassembledh