浙江轨道交通附属结构出入口土方开挖技术交底

'技术交底书工程名称宁波市轨道交通1号线一期工程TJ-Ⅶ标分部工程海晏北路站附属结构出入口分项工程出入口土方开挖技术交底技术交底内容：本次交底范围为海晏北路站附属结构出入口土方开挖工程。一.工程简述本工程宁波市轨道交通一号线海晏北路站，车站主体位于宁穿路。本工程施工包括5个出入口、2个风道。其中2号及3号出入口位于车站北边，4号、5号出入口位于车站南边，1号风道位于车站西端的南边，2号风道位于车站东端的南边，与5号出入口合建。主体均位于地下，与站厅层连接，采用明挖法施工。出入口基坑深度约9.5m左右，施工采用SMW工法桩，SMW工法桩长度为19m左右。SMW工法桩桩身采用42.5普通硅酸盐水泥，桩径850mm，搭接250mm，桩中心距600mm，内插H700×300×13×24型钢，型钢材料为Q235B钢，桩长为19m到24m不等，“隔一插二”内插型钢（局部基坑采用密插或隔一插一）。二.工程地质及水文地质2.1工程地质条件拟建场地第四纪地层发育，厚度大于70m，成因类型以海相沉积为主，总体特征：（1）沉积物粗细韵律变化明显，总体趋势呈自老至新粒度变细，具多旋回性。（2）沉积物的沉积环境由陆相向海相过渡。中更新世早期以洪积为主，中更新世晚期～晚更新世早期以冲积、冲湖积为主，晚更新世晚期以海陆交互沉积为主，全新世则以海相沉积为主。根据地质条件并结合工程性质，场地地基土分析如下：1、①层细分为4个亚层：①1-1层杂填土、①1-5层灰黑色浜底淤泥、①2层灰黄色粘土和①3层灰色淤泥质粘土。2、②层可划分为2个亚层：②2-1层灰色淤泥和②2-2层灰色淤泥质粘土。boxbeforecommissioning,checkdistributionboxthereisnodebris,installationinaccordancewiththecriteriaofqualityassessment,chromatography,platesarecomplete.2boxesinsidethedoorsandframes,andgroundedorneutralexamination.3withelectricopeningdoors,doorandframegroundterminalapplyingbarebraidedcopperwireconnectionsandgroundingidentifies.4connectionoftheprotectiveconductorshouldbeexposedintheexternalprotectiveconductorTerminal.5lightingshouldbesettingthezerolinebox(n)andprotectiveground(PE)bus,zerolineandprotectthegroundbusdistribution.6laidgroundlinesalongthelengthofevery15-100mmrespectively,coatedwithyellowandgreenstripes.7testinggroundingresistanceofgroundingdevicesmustcomplywiththedesignrequirements.8boxesofchecks:basedonchangesofdesigndrawingsandconstructiondocuments,checkboxinthecomponentspecification,model,installationlocationshouldbecorrect;boxesonbothsidesoftheTerminalcannotlack;theconductorcrosssectionshouldmeettherequirementsofdrawings;line-by-linecheckboxinthedevice"sconnectionandtheconnectionoftheequipmenttotheterminalblockinsidethebox.9boxtiecablecheck:liaisonbetweentheboxandtheboxcablesrequiredbyproofing;checklinesonthecircuitatthesametimeshouldcheckthewires,cables,relays,switches,buttons,terminalblocksmarkedwithlinedrawings.10operatorchecks:themaincheck 本工程附属结构基底设置于此层。①3层、②2-1层和②2-2层构成本场地软土层。3、③层划分为2个亚层：③1层灰色粉砂和③2层灰色粉质粘土夹粉砂。参考水利部行业标准《堤防工程地质勘察规程》(SL188-2005)，③1层灰色粉砂在明挖施工过程中，当具有一定水头的动水压力作用时易发生流土现象。③2层灰色粉质粘土夹粉砂：以软塑状为主，中压缩性，一般厚度为1.3～8.6m，层顶埋深为13.3～19.4m，层顶标高为-16.89～-12.58m。4、④层划分为2个亚层：④1-2层灰色粉质粘土和④2层灰色粘土5、⑤层划分成3个亚层：⑤1层暗绿色、灰黄色粘土、⑤2层灰黄色粉质粘土和⑤3层灰黄色砂质粉土。2.2水文地质条件施工场区地下水由浅部土层中的潜水及深部粉(砂)性土层中的承压水组成，其补给来源主要为大气降水与地表泾流，其排泄方式主要以蒸发形式排泄。根据地下水水质分析成果：场地地下水为低矿化度淡水，水化学类型以HCO3－Cl－Ca型为主。①潜水潜水主要赋存于浅部淤泥质土、粘性土、粉性土中，地下水位随降雨、潮汛影响而略有变化，根据区域地质资料，地下水位变化幅度不大，一般在0.5～1.0m之间。勘察期间测得的地下水初见水位埋深为1.00～4.00m，相对应的高程为-1.82～2.93m；稳定水位埋深为0.20～2.65m，相对应的高程为-0.47～3.12m。②承压水根据勘察报告及抽水试验报告知，本工程微承压含水层③1粉砂层、③2粉质粘土夹粉砂层初始水位埋深约2.0m，试验期间，抽水24小时后的稳定流量约为2～3m3/d。三.土方开挖一般规定及施工技术要求：1、土方开挖施工采用水平分段，垂直分层的方法施工。每段大约10m到15m之间，每层开挖不能大于3.5m深。2、抗拔桩及支撑周边土方开挖时，应采用小型机械开挖，施工过程中，严禁碰撞支撑及抗拔桩。在支撑较密的部位，开挖时，人工进行配合挖掘，并把土运到机械挖得到的地方，以便及时用机械挖走。boxbeforecommissioning,checkdistributionboxthereisnodebris,installationinaccordancewiththecriteriaofqualityassessment,chromatography,platesarecomplete.2boxesinsidethedoorsandframes,andgroundedorneutralexamination.3withelectricopeningdoors,doorandframegroundterminalapplyingbarebraidedcopperwireconnectionsandgroundingidentifies.4connectionoftheprotectiveconductorshouldbeexposedintheexternalprotectiveconductorTerminal.5lightingshouldbesettingthezerolinebox(n)andprotectiveground(PE)bus,zerolineandprotectthegroundbusdistribution.6laidgroundlinesalongthelengthofevery15-100mmrespectively,coatedwithyellowandgreenstripes.7testinggroundingresistanceofgroundingdevicesmustcomplywiththedesignrequirements.8boxesofchecks:basedonchangesofdesigndrawingsandconstructiondocuments,checkboxinthecomponentspecification,model,installationlocationshouldbecorrect;boxesonbothsidesoftheTerminalcannotlack;theconductorcrosssectionshouldmeettherequirementsofdrawings;line-by-linecheckboxinthedevice"sconnectionandtheconnectionoftheequipmenttotheterminalblockinsidethebox.9boxtiecablecheck:liaisonbetweentheboxandtheboxcablesrequiredbyproofing;checklinesonthecircuitatthesametimeshouldcheckthewires,cables,relays,switches,buttons,terminalblocksmarkedwithlinedrawings.10operatorchecks:themaincheck 3、土方开挖过程中，派人对支护结构进行配合监测，如发现支护结构有偏移过大的现象，立即采取回填加固等有效措施进行处理，待加固措施完成后，基坑偏移趋于稳定时才能继续进行开挖。4、防止施工顺序不合理，土方开挖必须自上而下进行，分层分段依次开挖，形成一定的坡度，以利于排水，严禁大锅底式开挖或超挖。5、防止基坑边坡不直不平，基底不平，尺寸不足的情况，加强检查，随挖随修，并认真验收。6、为保证开挖面不积水，以满足土方开挖的要求及后续底板防水工程的施工。土方工程施工期间必须组织排水和降水，使地下水及现场雨水，用潜水泵抽至基坑外排水沟。7、当土方工程挖方较深时，应采取措施，防止基坑底部土的隆起并避免危害周边环境。8、土方开挖过程应随时对基坑顶地面沉降、基底隆起、地下水位变化以及邻近周边道路进行了解，发现异常及时采取对策加以控制。四、施工操作工艺措施及主要做法要求4.1开挖方法待降水及冠梁施工完成后进行基坑开挖。（1）从南向北，由西向东依次顺序进行开挖，采用自然放坡、分层分段开挖。基坑开挖每层深度不大于3.5m。（2）开挖基坑采取“纵向分段、竖向分层、由上至下、中间拉槽、先支后挖”的原则，严禁超挖，在软土、粉砂层及变形要求较严格时，采取“分层、分区、分块、分段、抽槽开挖、留土护壁，及时支撑，减少无支撑暴露时间”等方式开挖。横向先开挖中间土体，后开挖两侧土,待两侧土体剩余30cm时用人工开挖，开挖过程中严禁机械碰撞钢支撑。（3）基坑开挖采用两台挖机相配合即可完成开挖和装车。1台小松60小挖机在基坑内进行倒土，一台VOLVO360长臂位于基坑边进行挖土和裝车。4）施工顺序和开挖示意竖向分层：竖向分层高度按立体结构尺寸、横撑排距及竖向层距以及挖掘机最大挖土能力确定。以冠梁顶起算，第一层土体开挖1.5m，安装第一道砼支撑；第二层土方开挖至地面下5m处，安装第二道钢管支撑及钢围檩boxbeforecommissioning,checkdistributionboxthereisnodebris,installationinaccordancewiththecriteriaofqualityassessment,chromatography,platesarecomplete.2boxesinsidethedoorsandframes,andgroundedorneutralexamination.3withelectricopeningdoors,doorandframegroundterminalapplyingbarebraidedcopperwireconnectionsandgroundingidentifies.4connectionoftheprotectiveconductorshouldbeexposedintheexternalprotectiveconductorTerminal.5lightingshouldbesettingthezerolinebox(n)andprotectiveground(PE)bus,zerolineandprotectthegroundbusdistribution.6laidgroundlinesalongthelengthofevery15-100mmrespectively,coatedwithyellowandgreenstripes.7testinggroundingresistanceofgroundingdevicesmustcomplywiththedesignrequirements.8boxesofchecks:basedonchangesofdesigndrawingsandconstructiondocuments,checkboxinthecomponentspecification,model,installationlocationshouldbecorrect;boxesonbothsidesoftheTerminalcannotlack;theconductorcrosssectionshouldmeettherequirementsofdrawings;line-by-linecheckboxinthedevice"sconnectionandtheconnectionoftheequipmenttotheterminalblockinsidethebox.9boxtiecablecheck:liaisonbetweentheboxandtheboxcablesrequiredbyproofing;checklinesonthecircuitatthesametimeshouldcheckthewires,cables,relays,switches,buttons,terminalblocksmarkedwithlinedrawings.10operatorchecks:themaincheck ；第三层土方开挖至地面下8.5m处，安装第三道钢管支撑及钢围檩，第四层土方开挖至开挖至设计基底标高以上30cm时进行人工清底，严禁超挖，基坑开挖竖向分层示意图见图1。横向分区分段依次开挖、放坡、支撑；见图2基坑开挖及施工平面示意图。图1竖向开挖示意图基坑施工顺序及开挖示意说明III号通道出入口土方开挖。顺序见图，基坑支撑共3道（局部为4道支撑），一道混凝土支撑两道钢支撑（局部为三道钢支撑，分两次开挖至基底（局部分三层挖至基底）。开挖土方量为42433。boxbeforecommissioning,checkdistributionboxthereisnodebris,installationinaccordancewiththecriteriaofqualityassessment,chromatography,platesarecomplete.2boxesinsidethedoorsandframes,andgroundedorneutralexamination.3withelectricopeningdoors,doorandframegroundterminalapplyingbarebraidedcopperwireconnectionsandgroundingidentifies.4connectionoftheprotectiveconductorshouldbeexposedintheexternalprotectiveconductorTerminal.5lightingshouldbesettingthezerolinebox(n)andprotectiveground(PE)bus,zerolineandprotectthegroundbusdistribution.6laidgroundlinesalongthelengthofevery15-100mmrespectively,coatedwithyellowandgreenstripes.7testinggroundingresistanceofgroundingdevicesmustcomplywiththedesignrequirements.8boxesofchecks:basedonchangesofdesigndrawingsandconstructiondocuments,checkboxinthecomponentspecification,model,installationlocationshouldbecorrect;boxesonbothsidesoftheTerminalcannotlack;theconductorcrosssectionshouldmeettherequirementsofdrawings;line-by-linecheckboxinthedevice"sconnectionandtheconnectionoftheequipmenttotheterminalblockinsidethebox.9boxtiecablecheck:liaisonbetweentheboxandtheboxcablesrequiredbyproofing;checklinesonthecircuitatthesametimeshouldcheckthewires,cables,relays,switches,buttons,terminalblocksmarkedwithlinedrawings.10operatorchecks:themaincheck II号通道出入口土方开挖。顺序见图，基坑支撑共3道（局部为4道支撑），一道混凝土支撑两道钢支撑（局部为三道钢支撑，分两次开挖至基底（局部分三层挖至基底）。开挖土方量为5831m3。V号通道出入口及II风道土方开挖。顺序见图，基坑支撑共3道（局部为4道支撑），一道混凝土支撑两道钢支撑（局部为三道钢支撑，分两次开挖至基底（局部分三层挖至基底）。开挖土方量为9637m3。图2基坑开挖及施工平面示意图4.2开挖技术措施（1）基坑开挖前，已在基坑内施工降水井，所以基坑内积水主要为土层含水及大气降水。每段基坑开挖时均要超前开挖水沟，将基坑内水汇入集水坑，用抽水机抽排至基坑外的排水沟。（2）基坑开挖过程中及时架设钢支撑，保证基坑正常开挖，在加载卸载过程中围护结构的受力符合设计。（3）基坑边缘堆置土方和建筑材料，或沿挖方边缘移动运输工具和机械，一般都应距基坑上部边缘不少于3m，弃土堆置高度不应超过1.5m，并且不能超过设计荷载值。（4）为保证坑底平整，控制超欠挖，基坑开挖到设计坑底标高以上30cm时，采用人工清底。基底应平整压实，其允许偏差为：高程-20mm～+10mm，平整度20mm，并在1m范围内不得多于1处。基坑开挖完成后，应减少暴露时间，防止曝晒和雨水浸刷破坏地基土的原状结构。boxbeforecommissioning,checkdistributionboxthereisnodebris,installationinaccordancewiththecriteriaofqualityassessment,chromatography,platesarecomplete.2boxesinsidethedoorsandframes,andgroundedorneutralexamination.3withelectricopeningdoors,doorandframegroundterminalapplyingbarebraidedcopperwireconnectionsandgroundingidentifies.4connectionoftheprotectiveconductorshouldbeexposedintheexternalprotectiveconductorTerminal.5lightingshouldbesettingthezerolinebox(n)andprotectiveground(PE)bus,zerolineandprotectthegroundbusdistribution.6laidgroundlinesalongthelengthofevery15-100mmrespectively,coatedwithyellowandgreenstripes.7testinggroundingresistanceofgroundingdevicesmustcomplywiththedesignrequirements.8boxesofchecks:basedonchangesofdesigndrawingsandconstructiondocuments,checkboxinthecomponentspecification,model,installationlocationshouldbecorrect;boxesonbothsidesoftheTerminalcannotlack;theconductorcrosssectionshouldmeettherequirementsofdrawings;line-by-linecheckboxinthedevice"sconnectionandtheconnectionoftheequipmenttotheterminalblockinsidethebox.9boxtiecablecheck:liaisonbetweentheboxandtheboxcablesrequiredbyproofing;checklinesonthecircuitatthesametimeshouldcheckthewires,cables,relays,switches,buttons,terminalblocksmarkedwithlinedrawings.10operatorchecks:themaincheck （5）开挖至基坑底时，及时浇注垫层封闭基坑，垫层要做到基坑满封闭。（6）监测体系，建立信息反馈系统，在开挖过程中对钢管支撑体系受力及稳定性、地表沉降，围护结构墙体倾斜、水位变化等派专人监测，并作好观测记录，出现异常立即处理。3、质量要求①为保证基坑开挖在无水条件下进行，开挖前先进行坑外降水，把地下水位降至最终基坑开挖面以下1米处，以疏干和加固土壤，待回填覆土后停止降水。②开挖过程用如遇围护结构侧面土体有渗水现象，及时埋设透水盲管将水导入基槽内的排水系统集中排出。③基坑必须自上而下分层、分段依次开挖，严禁掏底施工。放坡开挖基坑应随基坑开挖及时刷坡，边坡应平顺并符合规范要求。④基坑开挖接近基底300mm时，应采用人工清底，不得超挖或扰动基底土。基底超挖、扰动、水浸或发现异物、杂土、淤泥、土质松软及软硬不均等现象时，及时上报项目部并等待项目部处理措施确定后再进行施工。⑤雨季施工应沿基坑边做好挡水墙和排水沟。⑥基坑开挖允许偏差：高程-20mm～+10mm，平整度20mm，并在1m范围内不得多于1处，长度、宽度（从中心线往两边量）-50mm～+200mm。交底部门：施工技术部交底人：复核人：质检工程师：审批人：年月日承担班组：施工员（工长）：班组长：年月日boxbeforecommissioning,checkdistributionboxthereisnodebris,installationinaccordancewiththecriteriaofqualityassessment,chromatography,platesarecomplete.2boxesinsidethedoorsandframes,andgroundedorneutralexamination.3withelectricopeningdoors,doorandframegroundterminalapplyingbarebraidedcopperwireconnectionsandgroundingidentifies.4connectionoftheprotectiveconductorshouldbeexposedintheexternalprotectiveconductorTerminal.5lightingshouldbesettingthezerolinebox(n)andprotectiveground(PE)bus,zerolineandprotectthegroundbusdistribution.6laidgroundlinesalongthelengthofevery15-100mmrespectively,coatedwithyellowandgreenstripes.7testinggroundingresistanceofgroundingdevicesmustcomplywiththedesignrequirements.8boxesofchecks:basedonchangesofdesigndrawingsandconstructiondocuments,checkboxinthecomponentspecification,model,installationlocationshouldbecorrect;boxesonbothsidesoftheTerminalcannotlack;theconductorcrosssectionshouldmeettherequirementsofdrawings;line-by-linecheckboxinthedevice"sconnectionandtheconnectionoftheequipmenttotheterminalblockinsidethebox.9boxtiecablecheck:liaisonbetweentheboxandtheboxcablesrequiredbyproofing;checklinesonthecircuitatthesametimeshouldcheckthewires,cables,relays,switches,buttons,terminalblocksmarkedwithlinedrawings.10operatorchecks:themaincheck'