2022拉森钢板桩基坑围护施工方案.docx

2022拉森钢板桩基坑围护施工方案第一章工程概况工程概述三、施工场地条件= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =5第二章支护、支撑系统的结构设计= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 6、支护、支撑结构选型= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =6二、本工程投入的拉森钢板桩的参数= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 10三、基坑监测要求= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =10四、结构设计安全有效期=五、深基坑支护计算书= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 11第三章总体施工安排= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 11第四章基坑支护施艺及施工程序= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 12一、钢板桩支护施艺及施工= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =12二、旋喷桩支护施工方案= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 15三、基坑施工质量检测= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =18第五章基坑开挖及排水= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 1818二、基坑排水措施= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =21第六章施工进度安排= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 21第七章施工平面图= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 21施工现场平面管理措施=二、施工平面图（见附页）= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =22第八章资源配置计划= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 22一、机械投入计戈= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =23第九章检测控制措施= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 25、 王.兄-=一一 一一 一一 =一 = 25二、监测方案的依据= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =25三、监测技术要求= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =25四、监测组织= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =29五、观测频率= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =29六、工期= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 30七、安全监测信息化处理及监测漏呈= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =30第十章安全文明施工措施= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 36、安全施工措施= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =36二、文明施工措施= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =38第十一章保证措施= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =38一、管理保证= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =38二、组织保证= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =39三、劳动保证= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =39 四、机械保证= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =39 五、制度保证= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =39 六、培训= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =39 七、呆I正工期的技术后施=39第十二章应急救援预案= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =40、应急预案的方针与原则= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =40二、应急预案工作漏呈图= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =40三、B月挖深基坑开挖的的危险因素及预防、应急措施= = = = = = = = = = = = = = = = = = = = = = = = =41五、事故报告=45六、应"束= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =46 七、后期处置= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =46 、宣传教育= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =47九、演练= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =47十、总结= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =47应急救援预案淘呈图= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =49施工平面图= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =51基坑专项施工方案第一章工程概况、工程概述本工程建设起点为x=43979.351 , y=32877.763终点为x=44252.392 , y=33769.97 ,本工程污水管管径为D50DllOOmm , 总长4474米,预留支管管径为D300-D500,总长128米;截污管管径为D30D5OO,总长为152米;其中包括顶管、拉管、钢板桩 支护埋管等。本工程按污水管埋设的最大深度为最不利因素计算,本方案按设计图纸以5.8m深度逬行设计基坑支护, 基坑施工段支护总长度约3438.6米。二、工程地质和水文地质（一）工程地质路线所经过的地貌为*考州平原区的微丘、地势起伏不大,但不开阔,鱼塘密布。业区,仓库,商铺建筑密集,村落民房距离较 近,小山丘地形稍有起伏,植被茂盛。土地类别以菜田,鱼塘和旱地为主,其次是山地.根据本次钻孔所揭露岩土层情况,按岩、土层的成因,该区上覆第四系土层依次为:人工填土（Q4me）、第四系全新统海陆交互相沉 积层（Q4mc）淤泥质土、粉质粘土、粉砂、中砂.L第四系全新统人填筑土层（Q4me）1-1填筑土 :灰黄色或杂色,稍湿,松散状,主要由粉质粘土和少量碎石角砾组成,主要分布既有道路及绿化带表层,场地范围内均 有分布.2、第四系全新统海陆交互相沉积层（Q4mc）2-1淤泥质土 :深灰色,流塑,以粘粒为主,含少量腐殖质,土层稍具粘性及滑腻感,具高压缩性、高含水量、高孔隙比等特性,土 层力学性质极差。本层局部分布于迎新路段,北二环路段未见分布2-5粉质粘土 :灰黄色、灰褐色,软塑硬塑状,含少量粉细砂,迎新路段仅局部有揭示,北二环路段广泛分布。2-6粉砂:灰黄色、浅黄色、灰褐色,松散稍密,饱和状,主要成份为石英粒,零星分布。2-8中砂:灰白色、灰黄色、灰褐色,松散中密,饱和状。夹薄层粉细砂及少量砾石。本层仅在迎新路段的ZK-YXL-06钻孔中有分 布。迎新路段的其余钻孔及北二环路段均未发现。3、坡、残积土层（Qel+dl ）3-1砂质粘性土（ Qel+dl ）:褐红色、灰白色,硬塑,较松散,以粘粒、粉粒为主,含少量石英砂颗粒,由泥质粉砂岩或混合花岗岩风 化残积而成。整个标段内均有分布,部分钻孔钻穿该层。3-2稍密状粉、细砂层:以粉砂为主,部分为细砂,浅黄灰白色,饱和,稍密,含少量粘性土,分选性较差,颗粒级配不均匀。4、基岩4-1 全风化混合花岗岩（Z ）:灰白色,硬塑状，成分以粘土为主,钻孔岩芯呈土状及饼状。含有少许暗色矿物，原岩矿物除石英外, 均已风化成粘土矿物,遇水易软化、崩解。整个标段内均有分布，该层未钻穿。4-3 中风化混合花岗岩（Z ）:灰白色,磷片变晶结构,块状构造。部份矿物风化明显,裂隙发育,组织结构部份破坏,岩石较坚硬,多 呈块状。（二）水文地质第四系覆盖层中,素填土、粉质粘土、淤泥为相对隔水层,砂层为透水层及含水层,中粗砂赋水性良好,粉细砂稍差,粉细砂渗透系 数约为38m/d（经验值）,中粗砂渗透系数约为815m/d0基岩中节理、裂隙发育,为含水层,赋水性与岩性、风化程度或裂隙发育程度及连通性有关,裂隙越发育和连通性越好,一般赋水性 就越好,反之则较差,另外,一般全风化带、岩石风化剧烈,已土化,一般透水性和赋水性差。根据现场量测的勘察钻孔水位，勘察期间测得钻孔水稳定水位埋深2.50m ,标高为0.986.97m。本场地地下水类型可分为上 层滞水、孔隙潜水、孔隙承压水和基岩裂隙水。上层滞水主要赋存在人工填土层中,含水量较小,其动态受季节性控制，主要接受大气降水和生活用水的渗透补给;孔隙潜水主要储 藏在海陆交互相及冲积成因的砂层中,砂层厚度大,透水性良好，其主要补给来源为地表降水和上游地下水迳流,水量丰富;孔隙承压水 主要补给来源为外围含水层,其动态受降雨影响较小。场地基岩全风化、强风化及中风化裂隙发育，赋存有裂隙水,水量大小与裂隙度及 其连通性和补给条件有关。本次勘察揭露的地下水主要为第四系孔隙潜水、孔隙承压水。三、施工场地条件本段管线基坑开挖起点位于自由城市花园,途经马庄村、榄塘村、兴业大道段罗庄,终点为华南碧桂园段。马庄村段污水管线在村庄 出入马路上，重型汽车及工厂出入员较多。榄塘村管线位于新光快速一侧菜地,地理位置对施工较为有利。罗庄及华南碧桂园段污管线 位于城市主干道一侧，行人及车辆对施工有严重影响,各段施工都需做围蔽和疏导工作。第二章支护、支撑系统的结构设计、支护、支撑结构选型根据岩土工程勘察报告,本工程基坑开挖深度范围的土层主要为填土和淤泥,地质条件差,同时管道基坑深度较大,且不同地段管道 基坑底的地质条件不同,需根据不同的形式采用相应的支护方式。本工程根据基坑开挖深度,管道地基处理方式,以及内支撑的不同采用 了四种不同的支护方式。（一）管道基坑支护形式1、管道基坑支护方式基坑深度<3000 mm,采用6米长III型拉森钢板桩加一道内支撑进行基坑支护,钢板桩之间采用HW250*250*ll*l!围標逬行连接（ 直径DN300*10的钢管进行内支撑,支撑距地面1000廊。2、管道基坑支护方式二基坑深度<6000 mrn,基坑深度5000 mm的情况。采用9米长III型拉森钢板桩加二道内支撑进行基坑支护,钢板桩之间采用 HW250*25n*U围檀逬行连接，直径DN300*10的钢管逬行内支撑。第一道支撑距地面1000 mm ,第二道支撑距第二道支撑2000 mm03、管道基坑支护方式三基坑深度H<2000 mm的过河钢管的情况。过丹山河围堰截流，采用12米长ID型拉森钢板桩加二道内支撑逬行基坑支护，钢板桩之 间采用HW250*250*ll*ll围標进行连接，直径DN300*10的钢管逬行内支撑,第一道支撑距地面1000 mm ,第二道支撑距钢管顶面 500 mm。4、管道基坑支护方式四基坑深度H<3500 mm。高压旋喷桩采用双重管法施工，桩径为D500，桩距为30cm ,浆液主要材料为32.5R普通硅酸盐水泥，每延米300Kg水泥用量水灰比为1 ：1,喷嘴压大于等于24Mpa,速凝剂水玻璃按水泥用量的2%投加,空压机的压大于等于0.6 Mpao （管道基坑支护图>1W250x250x11x110009- 同 6c 0、Z2004 jg 151百Z一,:一 ,二v3ooxiomMltWt管道基坑支护方式钻孔剖面示意图2尔 仲 ,XXX，“"”加KG3oo)notw 對，HtmE3.004.60酝曲師WW250x250x11xn-T管道基坑支护方式二管道基坑支护方式三869 Z 。/86300 目管道基坑支护方式四二、本工程投入的拉森钢板桩的参数本工程投入的拉森钢板桩采用III型拉森钢板桩,宽400mm ,高170mm ,厚15.5mm ,理论重量68 Kg/m ,要求拉森钢板桩无穿 孔,修边调直后方可使用。拉森钢板桩之间用HW250*250*ll*l!围檀进行连接,围標与每根拉森钢板桩之间空隙需打入木楔抵紧。转角需设置专用构件,采 用(p300xl0钢管逬行内支撑,内支撑水平间距为4.0m ,管道安装需调整对撑间距并及时回顶。三、基坑监测要求L监测内容(1)基坑周边沉降及位移监测监测点和控制点均采用钢筋水泥制作,设置稳固。采用J2光学经纬仪或全站仪观测水平位移,采用精密水准仪观测垂直位移。基坑开挖期间每开挖层观测2次或每天观测2次,时间为上午开前,下午收工后。(2 )土体侧向变形监测沿基坑周边每20m布设一个测斜孔,测斜孔采用专用PVC管,管内正交的两组导向槽,埋入深度以逬入弱风化岩为宜。测斜孔埋 置时角保其中一组导向槽垂直于基坑边线,测斜孔与钻孔壁间的空隙密实填砂并用水泥密封。基坑开挖过程中每开挖支护层观测次。(3)地下水位监测观测孔成孔口径屮90,深15米,全长置入口径屮48向钻眼、外包塑料滤网的PVC管;PVC管与钻孔间隙1米以下填砾,深1米至 孔口填膨润土并用水泥砂浆抹面;PVC管口配保护盖。基坑开挖施工过程中,每开挖支护层观测次。本基坑支护结构的最大水平位移允许值,基坑按安全等级二级考虑,最大水平位移允许值为40mm。各项监测项目在基坑支护施工 前应测得稳定的初始值,且不少于2次。基坑监测完成时间为回填到标高±0.00 （从基坑开挖到底面后到基坑回填到标高±0.00这段时间 的观测间隔时间为715天。监测数值表监测项目警戒值控制值危险值土体沉降35mm40mm50mm墙体倾斜35mm40mm50mm墙体水平位移35mm40mm50mm第三章总体施工安排本基坑工程管道线性延伸,长约3.48Km ,拟根据不同地基处理形式及支护形式,分段施工。管沟支护采用12 m长II!型拉森钢板 桩支护1100m , 6m和9m拉森钢板桩支护2300m ,拟安排100延米一个作业面,平行组织流水作业。拉森钢板桩支护段打拔拉森桩 采用振动打桩机/锤,每个作业面2台,挖掘机3台。台超长臂挖掘机）。拉森钢板桩支护段拟采用200T履带吊垫钢板下管,吊车和人工配合管道对正,采用外拉法用两台15T手拉倒链平行对管子进行接 口。管道在穿越丹山河涌段拟在水利部门批准后的旱季施工,采用半幅粘土围堰截流（围堰宽4米,做施工便道）,半幅通水,围堰截流 后先用大口径轴流泵或潜水泵抽除围堰内部河水,待水位降低至作业面后明挖埋管,半幅施工完毕后拆除围堰施工另外半幅。便道布置在管道东侧征地线内,沿管线延伸,道路中线距管沟边6米。第四章基坑支护施工艺及施工程序、钢板桩支护施工艺及施工程序钢板桩采用III型拉森钢板桩,钢板桩之间采用HW250*250*ll*l!围標进行连接,围棟与每根钢板桩之间空隙须打入木楔抵紧,转 角必须设置专用构件。采用直径(p300xl0的钢管进行内支撑,管道安装须调整对撑间距并及时回顶。在块石填充满且密实度达到95% 时拆除块石垫层处的钢支撑,然后再吊装好管道后且回填石屑密实度达到90%以上后方可拆除管道上方的钢支撑,以此为准,每100米 为个作业段。1、钢板桩施工的一般要求(1)板桩的设置位置要符合设计要求,便于基础施工,即在基础最突出的边缘外留有施工作业面。(2)基坑护壁板桩的平面布置形状应尽量平直整齐,避免不规则的转角,以便标准板桩的利用和支撑设置,各周边尺寸尽量符合板 桩模数。(3 )整个基础施工期间,在挖土、吊运、浇筑混凝土等施工作业中,严禁碰撞支撑,禁止任意拆除支撑,禁止在支撑上任意切割、 电焊,也不应在支撑上搁置重物。2、板桩施工的顺序板桩准备围標支架安装一板桩打设一偏差纠正一拔桩。3、板桩的检验、吊装、堆放(1)板桩的检验对板桩,一般有材质检验和外观检验,以便对不合要求的板桩进行矫正,以减少打桩过程中的困难。外观检验:包括表面缺陷、长度、宽度、厚度、高度、端头矩形比、平直度和锁口形状等项内容。(2)板桩吊运装卸板桩宜采用两点吊。吊运时,每次起吊的板桩根数不宜过多,注意保护锁免受损伤。吊运方式有成捆起吊和单根起吊。成捆起 吊通常采用钢索捆扎,而单根吊运常用专用的吊具。(3)板桩堆放:板桩堆放的地点,要选择在不会因压重而发生较大沉陷变形的平坦而坚固的场地上,并便于运往打桩施工现场。堆 放时应注意:堆放的顺序、位置、方向和平面布置等应考虑到以后的施工方便;板桩要按型号、规格、长度分别堆放,并在堆放处设置标牌说明;板桩应分层堆放,每层堆放数量一般不超过5根,各层间要垫枕木,垫木间距。一般为3-4米,且上、下层垫木应在同一垂直线上,堆放的总高度不宜超过2米。4、导架的安装在板桩施工中,为保证沉桩轴线位置的正确和桩的竖直,控制桩的打入精度,防止板桩的屈曲变形和提高桩的贯入能力,一般都需要 设置一定刚度的、坚固的导架,亦称"施工围棟"。导架采用单层双面形式,通常由导梁和围標桩等组成(围檀桩的间距一般为2.5-3.5米,双面围標之间的间距不宜过大,一般略比 板桩墙厚度大8 15mm。安装导架时应注意以下几点:(1)采用经纬仪和水平仪控制和调整导梁的位置。(2 )导梁的高度要适宜,要有利于控制板桩的施工高度和提高施工效。(3 )导梁不能随着板桩的打设而产生下沉和变形。(4 )导梁的位置应尽量垂直,并不能与板桩碰撞。5、板桩施打(1)板桩用吊机带振锤施打,施打前一定要熟悉地下管线、构筑物的情况,认真放出准确的支护桩中线。(2 )打桩前,对板桩逐根检查,剔除连接锁口锈蚀、变形严重的普通板桩,不合格者待修整后可使用。(3 )打桩前,在板桩的锁口内涂油脂,以方便打入拔出。(4 )在插打过程中随时测量监控每块桩的斜度不超过2% ,当偏斜过大不能用拉齐方法调正时,拔起重打。(5 )板桩施打采用屏风式打入法施工。屏风式打入法不易使板桩发生屈曲、扭转、倾斜和墙面凹凸,打入精度高,易于实现封闭合 拢。施工时,将120根板桩成排插入导架内,使它呈屏风状,然后再施打。通常将屏风墙两端的组板桩打至设计标高或一定深度, 并严格控制垂直度,用电焊固定在围棟上,然后在中间按顺序分1/3或1/2板桩高度打入。屏风式打入法的施工顺序有正向顺序、逆向顺序、往复顺序、中分顺序、中和顺序和复合顺序。施打顺序对板桩垂直度、位移、轴线 方向的伸缩、板桩墙的凹凸及打桩效率有直接影响。因此,施打顺序是板桩施工艺的关键之。其选择原则是:当屏风墙两端已打设的 板桩呈逆向倾斜时,应采用正向顺序施打;反之,用逆向顺序施打;当屏风墙两端板桩保持垂直状况时,可采用往复顺序施打;当板桩墙 长度很长时,可用复合顺序施打。板桩打设的公差标准如下表所示。项目允许公差板桩轴线偏差±10cm桩顶标咼±10cm板桩垂直度1%(6)密扣且保证开挖后入土不小于2米,保证板桩顺利合拢;特别是工作井的四个角要使用转角板桩,若没有此类板桩,则用旧轮 胎或烂布塞缝等辅助措施密封。(7)打入桩后,及时进行桩体的闭水性检查,对漏水处逬行焊接修补,每天派专人逬行检查桩体。6、板桩的拔除基坑回填后,要拔除板桩,以便重复使用。拔除板桩前,应仔细研究拔桩方法、顺序和拔桩时间及土孔处理。否则,由于拔桩的振动 影响,以及拔桩带土过多会引起地面沉降和位移,会给已施工的地下结构带来危害,并影响临近原有建筑物、构筑物或底下管线的安全。(1)拔桩方法本工程拔桩采用振动锤拔桩:利用振动锤产生的强迫振动,扰动土质,破坏板桩周围土的粘聚以克服拔桩阻,依靠附加起吊力的 作用将桩拔除。(2 )拔桩时应注意事项拔桩起点和顺序:对封闭式板桩墙,拔桩起点应离开角桩5根以上。可根据沉桩时的情况确定拔桩起点,必要时也可用跳拔的方 法。拔桩的顺序最好与打桩时相反。振打与振拔:拔桩时,可先用振动锤将板桩锁口振活以减小土的粘附,然后边振边拔。对较难拔除的板桩可先用柴油锤将桩振下 10300mm,再与振动锤交替振打、振拔。起重机应随振动锤的启动而逐渐加荷,起吊般略小于减振器弹簧的压缩极限。供振动锤使用的电源为振动锤本身额定功率的1.2-2.0倍。 对引拔阻较大的板桩,采用间歇振动的方法,每次振动15min ,振动锤连续不超过1.5h。7、板桩土孔处理对拔桩后留下的桩孔,必须及时回填处理。回填的方法采用填入法,填入法所用材料为砂。二、旋喷桩支护施工方案江南新村小区内支管均采用基槽开挖旋喷桩支护方案。()旋喷桩施工方案1、旋喷桩施工方法喷浆采用二重管法,单喷嘴喷浆。喷浆导管直径100mm ,成孔采用XY-100地质钻机。成套设备配备如下表所示:高压旋喷桩施工成套设备配备表序号设备名称规格型号单位数量1地质钻机XY-100台12高喷台车PG-1500台13高压泵3D2-5Z台14灌浆泵HB-80台15空压机P-0.8MPa , Q-6m3/min台16泥浆泵BW-150台17搅拌机WJG-80台18二重管水、气、浆成桩套22、旋喷桩施工艺流程旋喷桩施工艺流程图2、旋喷桩施工方法和技术措施开始施工时,首先进行现场试验施工,逬步确定喷射参数及施工艺。根据地基加固范围内的特点,拟采用的施工参数如下表所示:二重管法高压旋喷桩施工技术参数表项目技术参数高压水水压(MPa)24流量(L/mim )80120喷嘴直径（mm）不小于2压缩空气气压(MPa)0.6流量(m3/min)1-2水泥浆液压(MPa)2流量(L/min)100-150注浆管提升速度（cm/min ）<10旋喷速度（r/min ）>10施工要点如下:先用钻机钻孔,然后移开钻机,将旋喷机移至孔位对中,将二重管放进孔中直至孔底,启动高压泵、空压机和旋喷机,用25Mpa高 压使浆流和气流从22.5mm的喷嘴喷射出来切割土体成桩,并缓慢提升至设计止浆高度。（1）钻导孔1）钻孔时采用膨润土配制泥浆护壁，泥浆的主要性能指标控制为:比重1.21.4 ,粘度2530",含砂率小于5%。2 ）测放孔位:根据设计图纸放设桩位，确保孔位的准确。3）钻机安装就位:先使钻机安置在标定的孔位上,使钻头中心对准孔位中心,调整钻机水平度和钻杆钻具的垂直度,保证孔倾斜率不大于1.5%。4 ）成孔:用XY-100钻机在桩位钻孔,钻孔深度与设计一致。为准确取得地质资料,合理优化施工技术参数,选取钻孔按地质钻探 孔要求对不同地层取样分析。5 ）钻孔施工质量标准:孔位差450mm ,垂直度41%。6）钻孔完成后经检查验收合格后,高喷台车就位,逬行喷浆作业。（2）浆液配制浆液采用32.5R普通硅酸盐水泥和自来水配制,速凝剂水玻璃按水泥用量的2%投加,水灰比1 : 1 ,采有立式搅拌罐搅拌。（3）旋喷注浆1）钻孔成孔后,在孔中下入三重管启动注浆泵和旋喷机,同时喷嘴喷出2025MPa高压水泥浆喷射冲切土体,旋喷机使三重管以 10cm/min的速度连续缓慢地旋动提升。在高压旋喷注浆过程中,注意防止喷嘴被堵,严格按设计的水灰比,压,流量,提升速度施工, 不能随意更改,并做好量测工作,及时正确地作好记录。台车就位安装调试完成后,将旋喷管插至孔底,先启动灰浆泵送浆,待孔口返浆后按方案设计的技术参数进行旋喷、提升。2 ）在旋喷过程中,随时注意各设备的工作情况,以及水、气、浆的压与流量,作好详实的施工记录。3）旋喷提升过程中如中途发生故障,立即停止施工,等检查排除故障后再继续施工。4 ）冒出浆液由泥浆泵抽至沉淀池沉淀处理。（4）回灌喷射注浆结束后,水泥浆不断析水固结,浆面随之下降,此时及时向孔内采用自然水压静压填充灌浆,直至液面不再下降为止。5、施工注意事项:水泥浆在旋喷前1小时内拌制,水灰比宜用1 : 1 ,旋喷过程中耗浆量控制在1025% ,由下往上喷浆,注浆管分 段提升的搭接长度不得小于100mm ,相邻两桩施工间隔时间大于2天且大于2倍桩距。四、基坑施工质量检测（一）钢板桩监测钢板桩的垂直度要求不超过1% ,钢板桩的轴线偏差为± 10cm。（二）搅拌桩质量检验检测内容:1、固结体的整体性及均匀性;2、固结体的有效直径;3、固结体的垂直度;4、固结体的溶蚀和耐久性能。检测方法:1、开挖检测;2、钻孔取芯;3、标准贯入试验;4、检验点为施工桩数的1% ,各项检验不小于3点。如质检部门有具 体要求,则按其要求进行检测。（四）止水帷幕止水效果检测在基坑开挖前进行抽水试验检测,抽水试验点不少于3点。第五章基坑开挖及排水、基坑开挖由于管槽开挖的土方量不大,每延米开挖出土量平均约7 9m3,每个作业段用二台挖掘机开挖与人工配合清底的方式,挖土要遵循 "纵向分段、竖向分层先支后挖"的原则进行。（二）支护、二、三（拉森钢板桩支护）管沟开挖支护:基坑深度<3500刖,采用6米长DI型拉森钢板桩加一道内支撑逬行基坑支护,支撑距地面1000 mmo支护:基坑深度H < 5000 mm ,采用9米长W型拉森钢板桩加二道内支撑逬行基坑支护,第一道支撑距地面1000 mm ,第二道支撑 在挖至基底后安装。支护三:基坑深度H<2500 mm过河钢管的情况采用!2米长III型拉森钢板桩加二道内支撑逬行基坑支护,直径DN300的钢管进行 内支撑,支撑距地面1000 mmo(1)支护、支护二、支护三基坑开挖配备二台挖掘机,采取分层分段对称逬行,在开挖过程中掌握好"分层、分步、对称、平衡、 限时"五个要点,遵循"竖向分层、纵向分段、先支后挖"的施工原则。(2 )在基坑开挖过程中先掏槽安装500mm (或-1000 mm )处钢围標、架设钢支撑,以尽早对围护结构进行支撑。自卸汽车运输, 基底以上30cm采用人工突击开挖,严格控制最后一次开挖,严禁超挖。(3 )分段开挖两端设截流沟和排水沟,渗水及雨水及时泵抽排走。雨季备足排水设备,做好预警工作,确保基坑安全。(4)开挖过程中,按既定的监测方案对基坑及周围环境进行监测,以反馈信息指导施工。(5)基坑开挖及出土示意图土方分层开挖断面示意图9a长!D型拉森钢板卷开挖及出土方法见下图。基坑开挖方向三、基坑排水措施鉴于本工程地下水位较高,施工现场距离河涌较近,本工程拟采用止水、导水、排水施工技术措施来保证工程施工顺利进行。(-)基坑排水措施沿基坑两边设350x350 mm的截水明沟,防止地表水流向基坑。沿坑底的两侧挖排水沟进行基坑内导水,排水沟紧贴