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集科研、生产、销售于一体的综合性企业

风电灌浆料-风电施工注意事项

时期:2021-01-07 10:16 点击数:
                                                                                  
施工准备
在沉桩施工之前,根据设计图纸要求和现场条件绘制沉桩顺序的平面图,检查桩体是否在允许的偏差范围内发生碰撞,并合理安排沉桩顺序。
1.施工现场调查
为了充分做好前期工作的准备,首先要对施工现场的地形,地质条件,水文,气象等自然条件进行调查研究,为制定合理的施工工艺,计算施工效率提供科学依据。并准备施工时间表。
2.进行各种施工程序
在施工开始之前,协助甲方单位办理有关手续和事项,如水上和水下施工作业许可证和航行通知书。
3.技术准备
(1)熟悉设计文件的内容以及与本项目有关的各种技术标准和规格,同时根据施工需要制作补充详细的施工图,并记录图纸的共同审核记录。
(2)根据调查数据,设计文件和业主要求,准备实施施工组织设计。
(3)重新测试和检查业主提供的测量控制点,建立项目的施工控制网络和施工基准。
(4)施工前对所有施工人员进行技术培训和安全培训。
(5)根据设计文件和施工组织设计,逐级完成技术澄清工作。
4.运营团队和管理人员的准备
(1)从从事类似项目建设的人员到驻站项目经理部门,选拔具有较高责任心和丰富类似施工经验的优秀项目管理人员,施工技术人员和各种施工人员。
(2)部分劳动力将从与本单位有长期劳动合作关系的劳动团队调动为从事建筑业的普通工人。
(3)根据施工进度的需要,可以将施工人员从福建,天津调到施工现场。
(4)签订合同协议后,将立即派遣人员。第一批人员将在3天内到达现场,建造生活和工程房屋,连接通讯,电力和供水系统,并确保实施
及时供应设备,材料和日用品。
5.材料准备
(1)施工开始前进行钢管桩的委托生产工作。
(2)履行项目所需的钢筋,水泥,型钢及其他材料的供应,接到中标通知书后立即进给并制造材料。
(3)进一步了解当地钢材,水泥,砂,石材等材料的生产面积,产量,质量,运输方式和单价,尽快落实供应商,签订供销合同。
6.建造船舶设备的准备
(1)制定施工设备使用的最佳方案,并使用先进的施工设备进行施工。施工设备应根据工程量,结构特点,施工需要等具体情况进行选择和合理安排。
(2)签订合同协议后,根据项目进度的需要,在子项目施工前,将各种船舶机械设备分批运往现场,以确保船舶性能良好。决不会由于设备的分发而造成的。影响施工进度。
(3)在将施工船舶机械设备运抵现场之前,进行检查和维修,建立船舶机械设备的技术性能和维护档案,使船舶机械设备始终处于良好状态,确保船舶机械设备顺利进行。那个工程。
(4)准备充足的设备易损零部件,加强对船舶机械设备的日常维护保养,充分利用施工间隔对设备进行日常维护,使船舶机械设备始终处于良好状态并确保建设顺利进行。
4.钢管桩的采购与运输
1.钢管桩的采购
钢管桩的生产由曹妃甸的一家钢管公司委托进行。选择应根据钢管桩的长度
对于重量等参数,钢管桩加工厂需要选择:(1)有一个能够处理95m桩长的场地。 (2)有能够起吊150t重量的起重设备(3)有船坞。 (4)具有防腐施工能力。
钢管桩出厂前,施工单位应对钢管桩的数量和质量进行严格的检查和验收,并在装船前提交完整的产品质量证明。
(1)钢管桩的技术要求:
由于钢管桩长且厚度分别为30mm(桩顶标高〜-45m),25mm(-45m〜-55m)和22mm(-55m〜桩尖高),因此将钢管桩分为三个部分然后进行焊接。
①分段生产钢管桩
钢管桩采用轧制直焊型,材质为Q345C。采用双面埋弧自动焊接,埋弧自动焊接无法达到的零件为手工电弧焊。必须根据设计要求打开焊接槽以确保熔深。
将钢板放下和冲裁时,会根据技术要求预先设置切削,磨削,刨平和焊接收缩等加工余量。在轧制钢板之前,请去除阻碍坡口焊接的毛刺和氧化物;使用自动火焰切割机放样钢板,并根据图纸要求打开相应的斜面。钢管在大型三辊卷取机上轧制。
管接头的纵向焊缝采用双面埋弧自动焊接,先焊接内部纵向焊缝,再焊接外部纵向焊缝。在进行外部纵向缝焊之前,应清洁内部焊缝的根部,以除去焊渣和焊缝根部的不完全渗透,并在焊接前露出焊接表面的金属光泽。根部清洁采用碳弧气刨工艺,辅以电动砂轮打磨。
②组装钢管桩
配对前,对钢管截面进行斜面处理,清除斜面内和周围的锈,油,水分和碎屑,不得超过30mm。根据规范要求,制作钢管桩拼接段的过渡槽。在专用架子上进行表演。当管接头配对时,任何部分都只有一个轴向接缝(不包括钢筋箍的轴向接缝)。通过管接头组的检查后,进行定位点焊。圆形焊缝在两侧焊接,内侧的焊缝先焊接,然后再焊接外侧的焊缝。在进行外周缝焊之前,应采用碳弧气刨工艺清洁焊根,并辅以电砂轮磨削。
(2)钢管桩的防腐要求
钢管桩的防腐采用防腐涂层和牺牲阳极。在打桩过程中进行防腐涂层,打桩后在水下焊接牺牲阳极防腐层。防腐涂料分为800μm改性环氧树脂涂料(-3.4m〜(-25.0m〜-29.0m)),800μm玻璃鳞片涂料(-0.5m〜-3.4m)和牺牲阳极两种材料。由铝合金阳极制成。
2.钢管桩运输
(1)装运前应进行钢管桩的数量和严格的质量验收,制造商在进行装载操作之前应提交完整的产品交付质量证明书。
(2)使用2000吨见方的驳船运输钢管桩。桩驳船主要根据桩长进行选择,应选择长度不小于90m的驳船。驳船可以用拖船拖曳。
驳船配备了符合要求的系泊设备。驳船应严格按照装运通知中指定的顺序装载,以使首先使用的一个首先装载,而第二个首先装载。
(3)在驳船上装载桩时,桩的底部应通过波纹布置并均匀放置,并且波纹的顶面应放置在同一平面上;楔形木块应放置在桩体的两侧,桩的外侧应焊接槽钢横向极限。然后用钢丝绳和张紧器将桩固定在桩运驳船的甲板上。土工布用于钢管桩之间以及对钢管桩施加应力的地方,以防止防腐蚀涂层损坏。
五,沉桩施工过程
5.1施工部署
钢管桩试验桩的工艺布置:本项目共布置2个试验桩。测试桩布置在风力涡轮机的中心,两个测试桩布置在2个原型中。尝试下沉桩时,应先沉降测试桩ZZ1,然后在下沉桩成功后再测试第二个测试桩。然后根据设计的沉桩顺序建造其他沉桩。桩沉完成后,安装平台,移去桩头,将桩心中的土壤清除至-35.0m,并灌注桩芯C30微膨胀芯混凝土。灌注桩心混凝土并完成28天后,进行桩基础检查测试。
5.2沉桩水处理流程
施工准备→钢管桩施工→钻井平台架设→孔的形成→降低钢笼→降低管
→浇筑水下混凝土→桩基础检查
5.3主要施工程序和方法
1.建筑船设备
我公司计划投资的主要大型船舶机械设备有:打桩船,混凝土搅拌船,拖船,方驳船等。
主要施工船舶设备清单
机器名称
额定功率(kw)或
容量(m3)或吨位(t)
编号备注
打桩船的最大打桩能力为108m(考虑水深),钢管桩1个
在2000t甲板驳船上运输1根钢管桩
搅拌船150m3 / h 1混凝土搅拌
拖轮2944kw 1牵引打桩机
锚船764kw 1船锚和掉锚
运输人员放入的运输船,打桩船(1)
计划投资用于钢管沉桩施工的打桩船。要求施工船灵活移动以适应桩帽的施工;与传统的打桩船相比,它可以抵抗更大的风浪,并且具有更长的运行时间的优势。
(2)放入桩锤
考虑到该项目中钢管桩的长距离,为确保钢管桩能够顺利打入预定深度并满足施工效率要求,建议使用德国的D-200制成了具有最大冲击能量的圆柱形柴油打桩锤。击中或选择BSP CG370液压桩锤。 BSP液压锤工作干净,没有废气排放。
英国生产的BSP CG370打桩锤与备用锤连接。更换锤子不需要其他处理。锤垫也是英国生产的聚合物材料。
液压锤主要技术性能表
模型
最大
能源
中风
(毫米)
总长度
度(m)
(次
休克
频率
(次
基本的
重量
(公斤)
基本的
长度
(毫米)
职位
压力
职位
D200柴油桩锤主要技术性能表
最大型号
能源
(Nm)
爆炸
(KN)
(次
休克
频率
(次
质量
(公斤)
(3)放入混凝土搅拌容器
计划放置一个150m3 / h的混凝土搅拌容器来搅拌混凝土,然后通过船上的HG40混凝土输送和分配机将混凝土泵入模具。
(4)放入多功能驳船:
临时桩和钢平台的安装和拆除计划于2000t方驳船+ 200t起重机船投入运营。
2.钢管桩的施工
(1)沉桩施工过程
停泊了打桩船,装载方形驳船,停在桩面上,在桩面上标记
将船移动到位,将桩提升到长嘴中,关闭下后板,并调整长嘴的倾斜度
测量定位桩的自沉,微调偏移量,并卸下吊锤
锤击打桩记录停止锤击以举起吊锤并测试打桩偏差
(2)打桩船停放和打桩顺序
本项目施工中使用的打桩船具有机动性强的特点。在建造过程中,我们的单位将充分利用船舶的这一功能,以减少锚索的数量,从而节省时间并节省海域。沉降桩的顺序应参考设计要求。
(3)沉桩定位
通过使用“海上长距离GPS打桩定位系统”来实现打桩船的打桩定位。
该系统由两个GPS移动站和三个测斜仪组成,以RTK模式实时控制船体的位置,方向和姿态。同时,它与固定在船上的两个无棱镜测距仪配合使用,以确定桩在一定高度处的相对位置。可以从桩在设计立面上的实际位置计算出船体桩架的距离,并显示在系统计算机屏幕上。通过与设计坐标进行比较,将船移动到位,直到打桩船的就位偏差满足要求,然后放下桩并开始行驶。
通过调节起重机吊钩头的位置,并通过在船舷上安装液压调平装置,调节钢桩的垂直度来满足设计要求,来调节桩体的垂直度。
操作要点:
①在打开计算机之前,请先关闭GPS电源,然后在计算机正常启动后再打开并打开GPS。
供电,可以保证系统的正常运行。
②请注意操作界面上“ LRK”字母的大小写,间距的差异以及指针的倾斜角度,以识别GPS锁。
③选择“精确模式”时,必须注意测距仪是否工作正常,否则桩位置会出现较大偏差。如果测距仪不能正常工作,则只能选择“标准模式”。
④界面上的“平均高度”数据是指测距仪红点的高程,可以用作高程控制的基础。
⑤使用GPS两次(即在第一次定位后关闭GPS,然后再次打开GPS)。如果两个桩位置数据的偏差相同,则可以放下桩,或者可以预先测量这两个点并将其放置在打桩机上,并在船舶驶入时计算这两个点的理论坐标。直立姿势。在实际驾驶第一个桩时,在定位之后,请使用GPS背包测量这两个点的坐标,然后计算桩位置的坐标。如果桩位置偏差满足要求,可以降低桩。
⑥可以根据GPS天线的高度推断出桩船的其他高度。
(4)打桩用锚索的布置
根据施工现场的现状,打桩船在下沉每个桩帽的过程中,将八字形锚和前后穿心式锚抛向横流。根据盖的堆放位置的特征,通过下沉流和下游流的结合来驱动下沉。
打桩驳船和打桩船的长边轴与水流方向成45度角。提起桩后,将驳船立即调节至下游状态,以减小船体的水面并避免锚定。
(5)沉桩施工
1.将桩抬起
在将打桩船移至桩运驳船之前,使用大小钩将预先安排的钢丝扣挂在桩上。在对钢桩进行预制并涂上防腐涂料之前,应根据施工要求对耳环进行焊接。大号和小号钩子用于将钢桩从驳船上水平提起并将船移到位。同时,提起小钩,使桩垂直竖立在龙嘴的前面。松开小钩,用带扣将桩挂起来,使桩垂直进入龙嘴。牢牢放下垫板,提起桩顶皮带,拧紧锚索,然后移动船舶,直到在测量位置的控制下桩位置在允许的偏差范围内。锤击后,应仔细观察桩身的变化并及时进行调整,以确保桩身的正确性
2.锤打桩
锤击时,请确保桩锤,交替驱动和桩柱在同一直线上。交替驱动应保持平整,以免发生偏心锤击。锤击应该是连续的。应注意桩下沉的过程,以防止事故和桩尖进入支承层。此后,每下沉10厘米记录一次锤击次数和锤子的下落距离,并严格遵守根据试验桩设计确定的锤子停止标准。
3,沉桩施工作业技术要点:
○1打桩前,请仔细检查桩的规格和型号,并检查桩身的外观质量。
②根据地质资料分析,打桩施工中可能会遇到桩滑土层。当桩基到达该土壤层时,应使用低速齿轮以减少锤击能量,以避免桩打滑。
③下沉钢管桩后,在桩下沉区的两端设置警示标志,夜间设置警示灯。
④考虑到项目所在海域的潮流速度和强风浪,应在风速和风浪尽可能小的情况下进行沉桩。原则上,当速度大于2m / s,风速大于6级,波高H> 1.2m时,应停止打桩。
⑤为适应离岸较远的公海沉桩事故,应安排专人听天气预报,以便及时转移避风处,检查所有船舶的锚索,起锚机和锚重。提前进行部分修改,必要时增加备份。数。
⑥在打开锤子之前,请检查锤子和交替驱动器是否与桩子在同一轴线上,以免发生偏心锤击,否则可能导致桩子顶部变形。
pile在自沉,锤击和锤击过程中,不得移动船舶以校正桩位置,以免桩变形。
driving如果在打桩过程中发生晃动,应暂停锤击直到桩体稳定为止,然后才能继续进行锤击。
⑨在打桩过程中,始终要注意检查打桩锤,交替打桩和打桩架的龙口,并及时处理。
⑩严格执行沉桩锤的标准。如果在下沉施工过程中发生异常渗透,桩体突然下沉,过度倾斜,移位等情况,应立即停止锤击,及时查明原因,并采取有效措施。
11进行打桩记录。
(6)临时桩施工
为了确保完工的钢桩保持稳定,在下沉桩桩后及时对桩帽钢管桩进行夹紧和加固,以抵抗风浪,便于后续的桩头切割施工。考虑到施工周期,将桩夹和钻井平台结合在一起。桩下沉完成后,竖立平台的主梁。主梁架设完成后,将箍与型钢两两相连,还可用作高程测量和桩头切割的操作平台。 。
(7)沉桩质量标准:
本项目下沉桩锤的标准主要基于高程控制。在通过试桩结果后,将确定相关的下沉控制标准。如果施工过程中出现异常情况,请及时与设计人员沟通。
钢管桩下沉实测项目
订单项的指定值或允许偏差的检查方法和频率
1个桩尖高程(mm)或最后一个
穿透力(mm /射)
检查桩沉记录是否符合“规范”的要求
2桩顶在设计标高处的平面位置
设定(毫米)
直桩250mm,斜桩300mm使用GPS定位
3度倾斜(斜桩)
少于10
(8)沉桩施工船机设备
沉桩施工船机设备表
所需的船舶设备名称(船)的数量
1桩船1钢管桩
方驳1钢管桩运输
3多功能驳船1钢管桩夹加固桩
拖船1拖拉打桩机
拖轮1拖船驳船,多功能驳船
锚船1船锚和锚点
7运输船2运输人员
(9)沉桩施工效率分析
本项目共需要36桩,一组9桩,共4组。根据类似项目的打桩经验,每个有效工作日都可以下沉桩,但需要一个有效工作日才能完成。考虑到天气,海洋环境,地质条件和其他外部因素对项目施工的影响,完成所有桩基所需的施工时间为1天。
3.搭建钻井平台
施工准备
设定高度
测量网和工程桩
桩位检查
箍施工微调箍高
材料进来
检查平面位置并抬高焊接下三角腿
铺设次梁
衡量并还清
箍加工
铺设木制广场
钻到位
施工平台采用钢箍支撑系统。箍的两侧都增加了焊接牛腿。在中间的直桩和八个工程倾斜桩上安装了一个1米高的钢箍。拧紧螺栓后,产生箍和钢桩。摩擦力转化为上层建筑的支撑力。平台顶面的高度是根据《海港平面设计规范》确定的,该规范规定E = H + h +η+Δ= 4.8米(H是设计高水位,最初设计为1.016, h是平台上部结构的高度,临时为0.2米,Δ在波峰上方至平台上部
该结构的底面的富裕高度暂时取为1m,η为波峰面的高度。该设计暂定为2.589m。主梁由双件[40a]组成,呈扇形排列,并直接放置在钢箍的牛腿顶部。在倾斜桩上设置了三角形的腿,以加强对主梁的支撑。三角形支腿要在距对角箍下边缘0.8m处设置另一个小箍。型钢的一端焊接到箍的顶板上,另一端焊接到主梁。与主梁焊接时,需要10mm厚的钢垫。板脚和三角脚也使用双引脚[40a。
(1)箍和主梁的施工
加工厂完成后,钢箍将被运送到现场。为了增加摩擦力,橡胶板预先用801胶水粘到箍上。在施工过程中,首先将箍的顶部高程线释放到桩上,然后方形驳船起重机将箍吊起并将其插入钢桩中。当基本达到高度时,使用倒链将铁环挂在桩顶,抬起钩子,然后使用倒链。进行微调,在箍达到预定高度后收紧箍,然后在全部9个大箍都装好后开始吊起主梁。
(2)二次梁施工
安装主梁后,将测量并放置副梁的位置。两个相邻梁之间的中心距离为0.8m。副梁由[40a钢制成。当竖立次梁时,对称地进行施工,并焊接固定主梁。
(3)铺设木制方块
副梁的安装完成后,进行铺路施工。木制面的两端用10#铁丝固定在副梁上。当钻机移动到相应的桩位置时,将木侧暂时从该位置移开,并及时完成钻孔。
(4)平台高度调整
根据相关设计要求,首先进行现浇桩的施工,并在桩基检查完成后进行顶盖的施工。平台的高度和桩顶的高度要求为+ 4.0m,并且在测试桩检查期间,平台的高度要求为大约?m,并且平台的底部高度为- 0.5m因此,施工平台设计首先要考虑平台的底部
然后使用液压千斤顶根据相应的高度抬起平台。
平台高度调整使用9个液压千斤顶进行提升操作。千斤顶布置在密封的钢瓶上,通过极梁和箍连接。调整到相应的高度后,拧紧箍:
①用5mm钢板密封所有钢管桩,密封后根据实际情况竖立两种[40a钢],作为千斤顶的支撑系统。
②以最大行程将千斤顶安装在型钢上,并在千斤顶上放置2.5m长的I36a双层I36a型钢,型钢之间的间距为5cm。
③将带有挡板的HPB400型材穿过双拼I36a型材中心。
④将HPB400的轮廓调整到合适的位置,然后将下端焊接到箍上。
⑤松开所有环箍螺栓,从千斤顶中放出油,然后慢慢放低。将其放到高处后,拧紧铁环螺栓。
4.灌注桩的施工
4.1钻机选择
根据该项目的具体情况,用冲击钻对试验桩(直桩)进行打孔,将粘土倒入泥浆中,并通过正循环清洗工艺形成孔。在将孔打孔至设计的桩底高度,达到泥浆比重和其他符合施工规范的参数后,将钢笼放下并浇注水下混凝土。
(直桩)钻机性能参数表
项目名称单位备注
1钻机型号JK-8
2最大钻孔直径
3最大钻孔深度m 70
4台主机电源
5最大起重能力
6绞车起重能力
7主机重量T 10
8钻头重量T 6Φ1.6m钻头
9钻头尺寸长×宽×高7.6X2.2X8.5(施工状态)
ZJD-2800反向循环钻机用于倾斜桩。这种类型的钻机具有以下优点:
①全液压无级变速,减少钻杆和钻具的冲击损伤;
②可根据工况调整钻孔压力,并自动钻孔,确保钻孔垂直度和孔径精度;
③可自动加压钻削斜孔;
④动力头可倾斜,以快速拆卸和组装钻杆;
⑤悬挂的动力头和可倾斜的框架可以快速提起和释放钻具和钻杆。
(斜桩)全液压钻机性能参数表
项目名称单位备注
1钻机模型
2最大钻孔直径
3最大钻孔深度
4台主机电源
5最大起重能力
6机架导架倾斜25
7动力头倾斜45
8动力头速度和
转矩rpm 0-8
吨18 rpm 0-28吨6
9台整机尺寸米
10单机重量吨28
4.2钻孔桩的施工
(1)冲击钻(直桩)打孔
1.1钻机就位:在钢桩的顶部找到钢桩的中心点,使钻机塔头滑轮,钢丝绳和桩位置的三个点成一直线。倾斜。
1.2。打孔泥浆:在开始施工之前,调整钻头中心和钢桩中心点,使其重合,并添加粘土和水以制成泥浆。
1.3。敲击孔的形成:在完成制浆之后,可以进行正式钻孔。钻机使用绞车和钢丝绳提起锤子以形成孔。 Pay attention to the drop hammer height when punching holes. Normally, 1-1.5m is appropriate. The initial stroke is small, and then the stroke is gradually increased. Due to the difficulty of this construction and high quality requirements, in order to ensure the smooth progress of drilling, the mud performance should be adjusted at any time according to the ground conditions. Special attention should be paid to the probe stone to avoid partial holes. If there is a deviation, it should be adjusted in time.
1.4。 Sediment treatment and slurry change: After drilling to the design depth, use a mud circulating pump or a slag drum to carry out slag removal, and at the same time perform a slurry change, so that the specific gravity of the mud can reach about 1.1~1.2.
(2) Hydraulic drill (inclined pile) to make holes
When the drilling rig is in place, adjust the drilling rig base and the hydraulic rod of the drilling frame so that the inclination of the drilling rod and the frame is the same as the inclination of the steel pipe pile, and the drilling can be started after centering.
When drilling, use clean water and air lift reverse circulation drilling, equipped with a hob cone bit and a Φ320mm flanged drill pipe. The flange connection is sealed with an O-ring seal, and a centralizer is added in the middle of the drill pipe. Each pile A total of 3 centralizers are added to prevent the inclined surface of the borehole from sagging and affect the drilling efficiency, and to ensure that the borehole slope is consistent with the outer diameter of the steel pipe pile. Fast and low pressure drilling should be used when drilling in the soil, and the drilling pressure should be slightly increased when drilling in the sand and pebble interlayer. The key is to increase the air supply to suspend the larger sand and pebbles. When drilling in rock formations, the drilling pressure must be increased to reduce the drilling speed.
The two sides of the drill pipe are equipped with air supply pipes, and the compressed air of the air compressor passes through the
The air supply pipe is sent to the bottom of the drill pipe. The high-pressure gas is mixed with the mud to form a slurry-gas mixture with a density less than the mud at the bottom of the dry drill pipe. The slurry-gas mixture rises due to its small specific gravity, forming a negative pressure at the bottom of the drill pipe. Under the action of negative pressure, the mud underneath rises under the action of negative pressure, and continuously fills the slurry under the combined action of pneumatic momentum, thereby forming a flow, because the area inside the drill pipe is much lower than the annular cross-sectional area between the outer wall of the drill pipe and the pile wall , Forming a reverse circulation with extremely high flow rate and flow, carrying sediment from the drill pipe and discharged out of the pile.
When drilling, the condition of the soil layer can be judged according to the jitter of the drilling rig and the color of the circulating water. For example, the drilling rig is stable during the drilling process, and the circulating water level is yellowish-brown mud water. It can be judged that the bit is still in the soil; when the drilling rig appears Slight shaking, the circulating water is grayish green, and the mud becomes thinner, indicating that the drill bit has entered the strongly weathered granite layer. The core is sandy and easy to disperse by hand; the drilling rig shakes a lot, and the circulating water is blue-gray, gray-white or gray-yellow If the core is massive and columnar, the bit must have entered the middle weathered granite layer.
In order to ensure that the active drill rod and the passive drill rod are always on the same axis, the position of the guide should be constantly adjusted. The specific operation is mainly to control the auxiliary winch and adjust the tightness of the guide wire rope.
(3) Clear hole
After the hole is formed to the design depth, the inspection is performed first, and the hole is cleaned after meeting the requirements. It adopts secondary hole cleaning, and the hole cleaning adopts air-lift reverse circulation process. An air compressor is prepared on site. A pipeline is connected to the air compressor and sent to the bottom of the hole. The air compressor is used to turn the sediment at the bottom of the hole up, and then inject clear water to overflow the sediment. When cleaning the hole, use the first cleaning as the main and the second cleaning as a supplement. Try to ensure that the first cleaning achieves the effect. If the first cleaning sediment is still larger than the design requirement, perform the second cleaning. After cleaning the hole, the bottom sediment is strictly prohibited to be greater than 3cm.
To clean the oblique pile, the pipe should be processed and a guide bag should be made to ensure that the pipe is centered when the pipe is cleared and concrete is poured, and it is prevented from being scratched to the steel cage.
In order to facilitate the placement of the catheter, the length of the bottom section of the catheter is 3.8m, and the rest are 2.65m long standard sections, the outer diameter of the catheter is Φ250mm (wall thickness 8mm), the pipe joint is thick threaded connection, and the inclined hole needs to be equipped with a pipe guide The guide of the catheter is processed into a cone-drum shape, and the guide is processed with a thin iron sheet of δ=3mm and fixed on the catheter. According to the different installation positions, the outer diameter of the guide package should be about 10cm smaller than the steel cage. The bottom guide of the drill hole of about 60m can be arranged at a distance of 12m from the bottom of the guide tube, and another guide guide should be added every 20m upwards. The outer diameter of the guide tube is about 10cm smaller than the inner diameter of the steel pipe pile. The surface of the guide must be smooth and free of burrs to avoid jamming the steel cage.
4.3 Fabrication and installation of steel cage
The production site of the steel cage is set on the shore. Because the length of the steel cage of the pile foundation is not large, it is assembled into a complete steel cage during land processing. After the steel cage is completed, the steel cage is transported to the site by a floating crane. 。
① The processing and production of the steel cage must meet the specifications and design requirements. The stirrups and the main reinforcement must be spot welded firmly; the main reinforcement of the steel cage must be connected by a straight threaded sleeve.
②Choose to use the concrete protective layer pads made by the professional protective layer manufacturer, and the concrete pads are arranged in a plum blossom shape every 2M. The strength and compactness of the cushion shall not be lower than the strength of the bored pile concrete. The protective layer pad has advanced production technology, beautiful appearance and high strength.
③Single-strand double wire rope is used when lowering the steel cage. When the steel cage is installed, the steel wire rope fixed on the top of the drill is untied, and the hoist pulls the steel wire rope in the hole to the hole.
④When making the inclined pile reinforcement cage, set up and down guide slopes, with the lower mouth retracted inward and the upper mouth placed outside. At the same time, the reinforcing hoop is placed outside to prevent the pipe from getting stuck in the steel cage.
⑤Because the steel cage is a half cage, it is difficult to use the upper positioning. In order to prevent the steel cage from floating up during concrete pouring, a Φ14 steel mesh is welded to the Φ20 reinforcement bar at the bottom of the steel cage to rely on concrete.
The force of gravity compresses the steel cage tightly.
4.4 Concrete pouring
①Concrete is self-mixed with a mixing vessel with a construction capacity of 150m3/h, and is reported to the supervisor and the owner for approval; the concrete mixes strictly in accordance with the mixing ratio approved by the supervisor.
②Before use, the pipes used for concrete pouring should be tested according to the actual number and length of the sections used, and the water pressure test should be carried out. The test pressure should not be less than 1.5 times the working pressure.
③The first filling material must wait for the hopper to be filled with concrete before opening the stopper. The mud in the hole is turned out by the weight of the concrete and the downward force to avoid clogging of the duct.
④ Make a record of concrete pouring.
⑤When the steel cage is lowered, tie a thin rope on the top of the cage and bolt it to the top of the hole. When pouring the concrete, if the rope has a loose span, it is necessary to slow down the concrete pouring speed and reduce the buried depth of the pipe in the concrete. According to the design It is required to always ensure that the pipe port is buried in concrete more than 1.0m to make the concrete pouring compact.
⑥ Always pay attention to measuring the concrete pouring elevation to prevent accidents in which the pipe is buried or the pipe is lifted out of the concrete surface;
⑦According to regulations, the concrete with a height of 2.0m on the top of the pile core should be vibrated and compacted with vibrating rods, and at least two sets of standard test blocks should be kept for each pile.
⑧Number of first batch of pouring concrete:
When the concrete is poured, the amount of the first batch of concrete must be calculated and determined by the pile length, which is determined according to V≥πD2(H+ h+0.5 t)/4+ πd 2(0.5L-H- h)/4.
In the formula: V: the required number of the first batch of concrete (m3)
D: hole diameter (m), take
d: the inner diameter of the catheter (m), take
L: Drilling depth (m), whichever is
H: Initial embedding depth of catheter
h: The gap between the bottom of the pipe and the bottom of the drill hole, take
t: Thickness of sediment at the bottom of the hole before pouring (m), whichever is
已计算
⑨Re-check the hole depth and sediment thickness before concrete pouring, and the concrete pouring is completed at one time
⑩Check the pile tip elevation of the protective tube after the hole is formed to accurately calculate the processing length of the steel cage and the control elevation of the concrete pouring surface.
4.5 Quality inspection standards
Drilling quality standards
Number of allowable deviation inspections for serial number items
测量
测试方法
1 Elevation of steel cage top
Check one by one 1 Measure with steel ruler or level
The deviation of the longitudinal axis of the 2 holes is less than or equal to 40 mm. 1 Use theodolite or a steel ruler to measure both sides
Direction, take the larger value
3 hole depth meets design requirements
乞讨
1Measure with measuring rope
4 The aperture meets the design requirements
乞讨
1Measure with steel ruler
5 The depth of rock socket meets the design requirements
乞讨
1Measure with measuring rope
6 Thickness of sediment ≤50 mm 1 Measure with measuring rope
7 Inclination ≤ 1%, random check 10% and not less
1 Suspended wire measurement steel cage production quality standards
Allowable deviation of serial number item Allowable deviation of serial number item
1 Spacing between main bars ±10mm 5 Overlap double-sided welding length ≥5d
2 Stirrup spacing or spiral spacing ±20mm 6 Overlap single-sided welding length ≥10d
3
Rebar cage diameter ±10mm 7 welding seam width
Rebar cage length +100mm 8 weld thickness
6. Construction of platform
6.1 Construction process
The construction process is shown in the figure:
Platform concrete maintenance
Pouring platform concrete
Tie the steel bar of the cap and bury the embedded parts
Pile core suction
Hoisting pile core reinforcement cage, pouring pile core concrete
Cut the tension and compression rods and remove the truss beams
The back cover concrete is cured to 80% strength
Installation of sealing plate, reinforcement between piles, and concrete pouring of cap and bottom
Steel hanging box installed on water
Demolition of the temporary platform
Pile head treatment
Steel hanging box processing and transportation
Platform cleaning, auxiliary facilities and anti-corrosion
3.2 Fabrication and installation of steel hanging box
Steel hanging box production
The steel box structure is composed of three parts: the side wall, the steel bottom plate and the truss beam. The side wall of the steel box of the platform is assembled by 8 single pieces, and each single piece is an integral plane (without seams). The height of the box is 5.3 (the height of the platform) m.
The side walls of the steel hanging box are mainly composed of 2[28a channel steel, [28a channel steel, [10a channel steel, 8mm thick steel plate and 12mm reinforcement ribs, etc., for the specific structure, see the expanded plan view of the steel hanging box wall
3-1 Plan view of the wall of steel hanging box
3-2 Layout drawing of cantilever beam connection
The supporting structure of the steel hanging box adopts two-layer cantilever beams, the upper cantilever beam is connected with the side wall, and the lower cantilever beam is placed on the top of the steel pipe pile. For the specific structure, see the steel box cantilever beam connection layout drawing
The steel box bottom plate is mainly composed of the frame beam “Work 25a”, the main beam “Work 25a”, and the secondary beam “angle iron 75”. The steel box bottom plate of the platform is reserved with steel pipe pile holes. The steel box bottom plate and the pile joint are used A rubber strip is inserted as a water stop measure. For the specific structure, see the detailed drawing of the bottom plate of the steel box (3-3).
3-3 Details of the bottom plate of the steel box
The production of steel box is commissioned by a professional steel structure processing unit. First, it is finished on the stand according to a single piece, and assembled and formed in the base. Cut the material according to the requirements of the drawings, the processing accuracy meets the design requirements, and the flatness error of the assembly seam is controlled to be less than 3mm. Each single piece of the side wall, the side wall and the steel bottom plate are all connected by bolts, and the truss beam corbel and the side wall are welded. Customized rubber strips are used to seal the seams to ensure that the structure does not leak or seepage. According to the actual measured pile position, each side is appropriately enlarged 15~25cm to cut holes in the steel bottom plate pile position.
In order to increase the turnover frequency of the steel hoisting box, the outer side of the box and the seawater contact surface are treated with anti-rust and anti-corrosion treatment. The inner template of the steel hoisting box is coated with release agent to protect the steel plate from corrosion.
Before the steel box is shipped out, the installation position is marked on the box. The steel hoisting box adopts eight-point hoisting (the hoisting point is set on the wall of the steel hoisting box). The specification, angle, and height of the wire rope used for hoisting must meet the safety requirements.
Full and strength requirements. After the steel box was assembled at a wharf in Caofeidian, it was transported to the construction site on a square barge and hoisted by a 200t crane.
Steel hanging box installation
(1) Pile top treatment
After the pile sinking is completed, GPS is used to measure the design pile top elevation, and then the pile top is cut to the design elevation, so that the pile top forms a horizontal plane to facilitate the installation and positioning of the steel box. After the pile is cut, the deflection of the pile top is determined for the steel bottom plate to cut holes.
(2) Steel hanging box measurement, installation and positioning
Measurement and control of the opening of the bottom plate of the steel box: The GPS RTK mode is used to measure the deflection of the pile foundation and the elevation of the top of the pile. After the supervision is reviewed and approved, the next step is to carry out the bottom plate opening of the steel box template.
Measurement and control of steel box installation: Controlled by the sideline of the main beam of the steel box, put out the mark of the installation location of the steel box on the top of the pile, and weld the guide plate on the top of the pile to make the installation of the steel box smooth The guide plate is easy to place.
The steel hoisting box is hoisted as a whole, the hoisting vessel is carried at the high tide position, and the hoisting box is installed in place at the low tide position, and the connection and reinforcement work is completed in time to form an overall rigid connection with the steel pile. When hoisting the steel hoisting box, the steel hoisting box of the supporting platform adopts eight-point hoisting. Before the crane vessel carries the position, first carry a multifunctional barge on the other side of the bearing platform. The ship is equipped with generators and the equipment and materials used for installation; the crane vessel lifts the steel box to the machine position and carries it at high tide. , Break down the anchor; then lift the steel box slowly to the top of the pile cap, adjust the installation position, tighten the two cable wind ropes, and place the steel box under the command of the crane; in order to be more precise, use side mounting and side mounting The method of measuring and adjusting, gradually welding the guide plate and the limit plate. If the center deviation of the steel box and its inclination do not meet the specifications and design requirements, the
It will be adjusted from time to time to finally meet the requirements.
3.3 Concrete construction of the back cover
Reinforced concrete construction of cap and bottom
The back cover concrete is designed to be C30 concrete with a thickness of 80 cm. The steel bars inside the back cover concrete are determined according to the conditions of the construction site, and the pouring is completed at one time.由于承台混凝土在设计低潮位以下,施工时应乘低潮位进行施工,浇筑过程中保证浇筑速度大于潮水上涨速度,并保持混凝土在水位以上进行振捣,底层混凝土初凝前不宜受水淹没。
按照设计要求,承台结构混凝土(高度4.5m不考虑封底混凝土)需要一次浇筑完成,需要增加封底混凝土与桩基的握裹力措施:封底砼中间高度设置剪力键,采取在每根钢管桩四周焊接4根Ⅰ16工字钢,每根工字钢长3m,下部焊接3块18 mm厚的钢板作为支撑牛腿,每块焊接板均采用双面直角焊。通过工字钢下的焊接钢板承受上部现浇混凝土、侧模板及封底的自重,封底中配筋用于承受荷载引起的弯矩。封底混凝土配筋自行根据实际情况确定。
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