沉管灌注桩是指利用锤击打桩法或振动打桩法.doc

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1、沉管灌注桩是指利用锤击打桩法或振动打桩法，将带有活瓣式桩尖或预制钢筋混凝土桩靴的钢套管沉入土中，然后边浇注混凝土（或先在管内放入钢筋笼）边锤击或振动边拔管而成的桩。前者称为锤击沉管灌注桩及套管夯扩灌注桩，后者称为振动沉管灌注桩。为了提高桩的质量和承载能力，沉管灌注桩常采用单打法、复打法、翻插法等施工工艺。沉管灌注桩完工后应进行桩身完整性及单桩竖向承载力检测。 1定义 2原理 3工艺流程 施工准备 操作工艺 质量标准 完工检测 4预防危害 5注意事项1定义沉管灌注桩是土木建筑工程中众多类型桩基础中的一种。沉管灌注桩又称为打拔管灌注桩。它是利用沉桩设备，将带有钢筋混凝土桩靴 (活瓣式桩靴)的钢管沉

2、入土中，形成桩孔，然后放入钢筋骨架并浇筑混凝土，随之拔出套管，利用拔管时的振动将混凝土捣实，便形成所需要的灌注桩。利用锤击沉桩设备沉管、拔管成桩，称为锤击沉管灌注桩。利用振动器振动沉管、拔管成桩，称为振动沉管灌注桩。为了提高桩的质量和承载能力，沉管灌注桩常采用单打法、复打法、翻插法等施工工艺。 单打法(又称一次拔管法)：拔管时，每提升0.51.0m，振动510s，然后再拔管0.51.0m，这样反复进行，直至全部拔出；复打法：在同一桩孔内连续进行两次单打，或根据需要进行局部复打。施工时，应保证前后两次沉管轴线重合，并在混凝土初凝之前进行； 翻插法：钢管每提升0.5m，再下插0.3m，这样反复进行

3、，直至拔出。2原理利用锤击沉桩设备沉管、拔管成桩，称为锤击沉管灌注桩;利用振动器振动沉管、拔管成桩，称为振动沉管灌注桩。振动沉管灌注桩是用振动沉桩机将有活瓣式桩尖或钢筋混凝土预制桩靴的桩管(上部开有加料口),利用振动锤产生的垂直定向振动和锤、桩管自重等对桩管施加压力,使桩管沉入土中,然后边向桩管内浇筑混凝土,边振边拔出桩管,使混凝土留在土中而形成桩。与一般钻孔灌注桩比，沉管灌注桩避免了一般钻孔灌注桩桩尖浮土造成的桩身下沉，持力不足的问题，同时也有效改善了桩身表面浮浆现象，另外，该工艺也更节省材料。但是施工质量不易控制，拔管过快容易造成桩身缩颈，而且由于是挤土桩，先期浇注好的桩易受到挤土效应而产

4、生倾斜断裂甚至错位。施工准备1.材料（1） 水泥：425#及其以上的硅酸盐水泥、普硅、矿渣、火山水泥。水泥进场时应有出厂合格证明书。施工单位应根据进场水泥品种、批号进行抽样检验，合格后才能使用。水泥如存放时间超过三个月，应重新检验确认符合要求后才能使用。（2） 中粗砂：采用级配良好、质地坚硬、颗粒洁净的河砂或海砂，其含泥量不大于3%。（3） 石子：采用坚硬的碎石或卵石，最大粒径不宜大于40mm，且不宜大于钢筋最小净距的1/3，其针片状颗粒不超过25%，含泥量不大于2%。（4） 钢筋：钢筋进场时应有出厂质量合格证明书，应检查其品种规格是否符合要求及有无损伤、锈蚀、油污，并应按规定抽样，进行抗压、

5、抗弯、焊接试验，经试验合格后方能使用（进口钢筋要进行化学成份检验和焊接试验，符合有关规定后方可用于工程）。钢筋笼的直径除应符合设计要求外，还应比套管内径小60-80mm。（5） 桩尖：一般采用钢筋砼桩尖，也可用钢桩尖。钢筋砼的桩尖强度等级不低于C30。其配筋构造和数量必须符合设计或施工规范的要求。2.作业条件（1） 施工前应作场地查勘工作，如有架空电线、地下电线、给排水管道等设施，妨碍施工或对安全操作有影响的，应先作清除、移位或妥善处理后方能开工。（2） 施工前应做好场地平整工作，对不利于施工机械运行的松散场地，必须采取有效的措施进行处理。雨季施工时，要采取有效的排水措施。（3） 应具备施工区

6、域内的工程地质资料、经会审确定的施工图纸、施工组织设计（或方案）、各种原材料及预制桩尖等的出厂合格证及其抽检试验报告、砼配合比设计报告及其有关资料。（4） 桩桩机性能必须满足成桩的设计 要求。（5） 按设计图纸要求的位置埋设好桩尖，埋设桩尖前，要根据其定位位置进行 钎探，其探测深度一般为2-4m，并将探明在桩尖处的旧基础、石块、废铁等障碍物清除。（6） 桩尖埋设经复核后方能进行打桩，桩尖允许偏差值：单桩为10mm，群桩为20mm。（7） 应会同设计单位选定1-2 根桩进行打桩工艺试验（即试桩）以核对场地地质情况及桩基设备、施工工艺等是否符合设计图纸要求。（8） 其余参照打入桩的施工准备和作业条

7、件。操作工艺1. 锤击沉管灌注桩的施工方法一般为“单打法”，但根据设计要求或土质情况等也可采用“复打法 “。2. 锤击沉管灌注桩宜按流水顺序，依次向后退打。对群桩基础及中心距小于3.5 倍桩径的桩，应采用不影响邻桩质量的技术措施。3.桩机就位时，桩管在垂直状态下应对准并垂直套入已定位预埋的桩尖，桩架底座应呈水平状态及稳固定位，桩架垂直度允许偏差不大于0.5%。4. 桩尖埋设后应重新复核桩位轴线。桩尖顶面应清扫干净，桩管与桩尖肩部的接触处应加垫草绳或麻袋。5. 注意检查及保证桩管垂直度无偏斜后采正式施打。施打开始时应低锤慢击，施打过程若发现桩管有偏斜时，应采取措施纠正。如偏斜过大无法纠正时，应及

8、时会同施工负责人及技术、设计部门研究解决。6. 沉桩过程中，应经常使用测锤检查管内情况及桩尖有否损坏，若发现桩尖损坏或水泥进入，应拔出桩管，回填桩孔，重新设置桩尖进行施打。7. 沉管深度应以设计要求及经试桩确定的桩端持力层和最后三阵，每阵十锤的贯入度来控制，并以桩管入土深度作参考。测量沉管的贯入度应在桩尖无损坏、锤击无偏心、落锤高度符合要求、桩帽及弹性垫层正常的条件下进行。一般最后三阵每阵十锤的贯入度不大于30mm，且每阵十锤贯入度值不应递增。对于短桩的最后贯入度应严格控制，并应通知设计部门确认。8. 沉管结束经检查管内无入泥进水后，应及时灌注砼。每立方砼的水泥用量应不少于300Kg。当桩身配

9、有钢筋时，设计无规定时砼塌落度宜采用80-100mm；素砼的塌落度宜采用60-80mm。第一次灌入桩管内的砼应尽量多灌，第一次拔管高度一般只要能满足第二次所需要灌入的砼量时即可，桩管不宜拔地太高。9. 拔管时采用倒打拔管的方法，用自由落锤小落距轻击不少于40 次/min，拔管速度应均匀，对一般土层以不大于1m/min 为宜。在软硬土层交界处及接近地面时，应控制在0.6-0.8m/min 以内。在拔管过程中，应用测锤随时检查管内砼的下降情况，砼灌注完成面应比桩顶设计标高高出0.5m，以留作打凿浮浆。10. 凡灌注配有不到桩底的钢筋笼的桩身砼时，宜按先灌注砼至钢筋笼底标高，再安放钢筋笼，然后继续案

10、灌注砼的施工顺序进行。在素砼桩顶采用构造连接钢筋时，在灌注完毕拔出桩管及桩机退出桩位后，按照设计标高要求，沿桩周对称、均匀、垂直地插入钢筋，并注意钢筋保护层不应小于3cm。11. 对于砼灌注充盈系数小于1.1 的桩，应会同设计单位研究补救措施。12. 按设计要求进行局部复打或全复打施工，必须在第一次灌注的桩身砼初凝之前进行。13. 灌注桩身砼时应按有关规定留置试块。质量标准1.保证项目（1） 所用的原材料和砼强度必须符合设计要求和施工规范的规定。（2） 桩的入土深度应满足设计要求的桩端持力层，最后三阵每阵十锤的贯入度，最后1m 的沉管锤击数和整根桩的总锤击数，应符合设计及试桩确定的要求。（3）

11、 砼灌注充盈系数不得小于1.1。（4） 灌注后的桩顶标高、钢筋笼（插筋）标高，及浮浆处理必须符合设计要求和施工规范的规定。2.允许偏差锤击沉管灌注桩的允许偏差和检验方法应符合下表的规定。项目 允许偏差（mm） 检验方法主筋间距10箍筋间距20加强箍间距50直径 10钢 筋 笼 长度 100尺量检查1-2 根或单排桩703-20 根桩基的桩 d/2边缘桩 d/2桩 的 位 置移偏 桩数多于20 根中间桩 d拉线和尺量检查垂直度 H/100 吊线和尺量检查注：d 为桩径，H 为桩长。3.混凝土灌注桩质量检验标准项序检 查 项 目允许偏差或允许值检查方法主,控,项,目1桩位第4,1条基坑,开挖前量护

12、筒,开挖后量桩中心2孔深,(mm)+300只深不浅,用重锤测,或测,钻杆,套管长度,嵌岩桩应确保进入设计要求的嵌岩深度3桩体质量检验设计要求按,基桩,检测技术规范4混凝土强度设计要求试件报告或钻芯取样送检5承载力设计要求按基桩检测技术规范一,般,项,目1垂直度第4,1条测套管或钻杆,或用超声波探测,干施工时吊垂球2桩径第4,1条井径仪或超声波检测,干施工时用,钢尺,量,人工挖孔桩不包括内衬厚度3泥浆,比重（粘土或砂性土中）1,151,20用比重计,测,清孔后在距孔底1250px处取样4泥浆面标高（高于地下水位）（m）0,51,0目测5沉渣厚度,端承桩（mm）,磨擦桩（mm）50,150用沉渣仪

13、或重锤测量6混凝土,坍落度,水下灌注（mm）,干施工（mm）160220,70100坍落度仪7钢筋笼安装深度（mm）,100用钢尺量8混凝土充盈系数,1检查每根桩的实际灌注量9桩顶标高（mm）+30,-50水准仪,需扣除桩顶浮浆层及劣质桩体垂直桩基中心线12根桩d500mm时,70,d,500mm,时,100拉线和尺量检查单排桩群桩基础的边桩沿桩基中心线条形基础的桩d500mm时,150,d,500mm时,150拉线和尺量检查,注,d为桩的直径,H为桩长完工检测一、沉管灌注桩完工后应进行桩身完整性及单桩竖向承载力检测。二、宜先进行工程桩的桩身完整性检测，根据完整性试验结果选择有代表性的桩进行单

14、桩竖向承载力检测。三、桩身完整性检测应符合下列规定：1 桩身完整性检测应采用低应变法；2 检测数量不应少于总桩数的20%，且不得少于10根，每个承台不得少于1根。四、单桩竖向承载力检测应符合下列规定：1 对地基基础设计等级为丙级的建筑物及施工前已进行过静载荷试验的乙级建筑物，单桩竖向承载力可采用高应变动力检测方法评定，抽检桩数不应少于总桩数的5%，且不应少于5根；2 对地基基础设计等级为甲级的建筑物及不符合上款条件的乙级建筑物，单桩竖向承载力均应进行静载荷试验，抽检桩数量不应少于总桩数的1%，且不应少于3根。4预防危害（一）施工过程危害及控制措施序号作业活动危险源控 制 措 施1现场管理人员伤

15、害禁止无关人员进入现场,打沉,套管,应有专人指挥2桩机,操作机械损坏桩机操作人员应了解桩机性能,构造,并熟悉操作保养方法,方能操作3桩架装拆高空坠落在桩架,上装,拆维修机件进行,高空作业,时,必须系安全带4桩机行走触电桩机行走时，应先清理地面上的障碍物和挪动电缆，挪动电缆应戴绝缘手套，注意防止电缆摩损漏电5混凝土搅拌和钢筋笼制作混凝土搅拌和钢筋笼制作人员作好全面安全防护6振动沉管挤压振动沉管时，若用收紧钢丝绳加压，应根据桩管沉入度，随时调整离合器，防止抬起桩架，发生事故。锤击沉管时，严禁用手扶正桩尖垫料。不得在桩锤未打到管顶就起锤或过早刹车7桩机站立牢固桩机倾倒施工过程中如遇大风,应将桩管插入

16、地下嵌固,以确保桩机安全8人员均戴,安全帽高空坠物所有施工人员均戴安全帽,并进行安全教育（二）环境因素辩识及控制措施序号作业活动环 境 因 素控制措施1混凝土的搅拌污水排放设,沉淀池,清污分流2砂石料进场,垃圾出场扬尘砂石运输表面覆盖建筑垃圾运输表面覆盖道路要经常维护和洒水,防止造成粉尘污染3现场清理建筑垃圾施工现场应设合格的卫生环保设施,施工垃圾集中分类堆放,严禁垃圾随意堆放和抛撒4机械使用废油施工现场使用和维修机械时,应有防,滴漏,措施,严禁将机油等滴漏于地表,造成土地污染5注意事项1.避免工程质量通病（1） 为防止出现缩颈、断桩、砼拒落、钢筋下沉、桩身夹泥等现象，应详细研究工程地质报告，

17、制订切实有效的技术措施。（2） 灌注砼时，要准确测定一根桩的砼总灌入量是否能满足设计计算的灌入量，在拔管过程中，应严格控制拔管速度，用测锤观测每50-100cm高度的砼用量，换算出桩的灌注直径，发现缩颈及时采取措施处理。（3） 如采用跳打法施工，跳打时必须等相邻成形的桩达到设计强度的60%以上方可进行。（4） 严格检查桩尖的强度和规格，桩管沉至设计要求后，应用测锤量测桩尖是否进入桩管内。如发现桩尖进入桩管内，应拔出桩管进行处理。灌注砼后，拔管时，也应用测锤测量，看砼是否确已流出管外。（5） 钢筋笼放入桩管内应按设计标高固定好，防止插斜、插偏和下沉。（6） 拔管时尽量避免反插。确需反插时，反插的

18、深度不要太大，以防止孔壁周围的泥挤进桩身，造成桩身夹泥。2.主要安全技术措施（1） 在施工方案中，认真制订切实可行的安全技术措施。（2） 清除妨碍施工的高空和地下障碍物，平整打桩范围内的场地和压实打桩机行走的道路。（3） 对临近原有建（构）筑物，以及地下管线要认真查清情况，并研究采取有效的安全措施，以免震坏原有建筑物而发生伤亡事故。（4） 打桩过程中，遇有施工地面隆起或下沉时，应随时将桩机垫平，桩架要调直。（5） 操作时，司机应集中精神，服从指挥，并不得随便离开岗位。打桩过程中，应经常注意打桩机的运转情况，发现异常情况应立即停止，并及时纠正后方可继续进行。（6） 打桩时，严禁用手去拨正桩头垫料

19、，同时严禁桩锤未打到桩顶即起锤或刹车，以免损坏打桩设备。（7） 严格执行施工现场临时用电安全技术规范（JGJ46-2005）。3.产品保护（1） 钢筋笼在制作、安装过程中，应采取措施防止变形。（2） 桩顶锚入承台的钢筋要妥善保护，不得任意弯曲或折断。（3） 已完成的桩未达到设计强度70%，不准车辆碾压。（4） 打桩完毕开挖基坑时，要制订合理的施工顺序和技术措施，防止桩的位移、断裂和倾斜。（英文版 ） Two regulations promulgated for implementation is in the party in power for a long time and the ru

20、le of law conditions, the implementation of comprehensive strictly strategic plan, implementation in accordance with the rules and discipline to manage the party, strengthen inner-party supervision of major initiatives. The two regulations supporting each other, the adhere to a positive advocate, fo

21、cusing on morality is of Party members and Party leading cadres can see, enough to get a high standard; around the party discipline, disciplinary ruler requirements, listed as negative list, focusing on vertical gauge, draw the party organizations and Party members do not touch the bottom line . Her

22、e, the main from four square face two party rules of interpretation: the first part introduces two party Revised regulations the necessity and the revision process; the second part is the interpretation of the two fundamental principles of the revision of laws and regulations in the party; the third

23、 part introduces two party regulations modified the main changes and needs to grasp several key problems; the fourth part on how to grasp the implementation of the two regulations of the party. and revised the necessity and revised history of the CPC Central Committee the amendment to the Chinese Co

24、mmunist Party members and leading cadres honest politics several guidelines and column 1 by 2015 to strengthen party laws and regulations focus. Two party regulations revision work lasted a Years, pooling the wisdom of the whole party, ideological consensus, draw historical experience, respect for t

25、he wisdom of our predecessors, which reflects the unity of inheritance and innovation; follow the correct direction, grasp the limited goals, adhere to the partys leadership, to solve the masses of the people reflect a focus on the problem. The new revision of the and , reflects the partys 18 and th

26、e eighth session of the third, the spirit of the fourth plenary session, reflecting the experience of studying and implementing the General Secretary Xi Jinping series of important speech, reflects the partys eighteen years comprehensive strictly practice. (a) revised two regulations of the party ne

27、ed of in based on revised, the promulgation and implementation of January 2010, to strengthen the construction of the contingent of leading cadres play an important role. But with the party to manage the party strictly administering the deepening, has not been able to fully meet the actual needs. Co

28、ntent is too complicated, eight prohibition, 52 are not allowed to hard to remember, and also difficult to put into practice; the second is concisely positive advocated by the lack of prohibited provisions excessive, no autonomy requirements; the third is banned terms and discipline law, both with t

29、he party discipline, disciplinary regulations repeat and Criminal law and other laws and regulations repeat; the fourth is to clean the theme is not prominent, not for the existing problems, and is narrow, only needle of county-level leading cadres above. is in 1997 based on revision, in December 20

30、03 the promulgation and implementation, to strengthen the construction of the party play very important role. Along with the development of the situation, which many provisions have been unable to fully meet the comprehensive strictly administering the practice needs. One is Ji law, more than half o

31、f the provisions and criminal law and other countries laws and regulations Repetition; two is the political discipline regulations is not prominent, not specific, for violation of the party constitution, damage the authority of Party Constitution of misconduct lack necessary and serious responsibili

32、ty to pursue; third is the main discipline for the leading cadres, does not cover all Party members. Based on the above situation, need to and the two is likely to be more relevant regulations first amendment. By revising, really put the authority of Party discipline, the seriousness in the party tr

33、ee and call up the majority of Party members and cadres of the party constitution of party compasses party consciousness. (II) two party regulations revision process the Central Committee of the Communist Party of China attaches great importance to two regulations revision . Xi Jinping, general book

34、s recorded in the Fifth Plenary Session of the eighth session of the Central Commission for Discipline Inspection, on the revised regulations made clear instructions. According to the central deployment, the Central Commission for Discipline Inspection from 2014 under six months begin study two regu

35、lations revision. The Standing Committee of the Central Commission for Discipline Inspection 4 review revised. Comrade Wang Qishan 14 times held a special meeting to study two regulations revision, amendment clarifies the direction, major issues of principle, path and target, respectively held a for

36、um will listen to part of the province (area) secretary of the Party committee, Secretary of the Discipline Inspection Commission, part of the central ministries and state organs Department The first party committee is mainly responsible for people, views of experts and scholars and grassroots party

37、 organizations and Party members. Approved by the Central Committee of the Communist Party of China, on 7 September 2015, the general office of the Central Committee of the Party issued a notice to solicit the provinces (autonomous regions, municipalities) Party, the central ministries and commissio

38、ns, state ministries and commissions of the Party (party), the General Political Department of the military, every 3 people organization of Party of two regulations revision opinion. Central Commission for Discipline Inspection of extensive solicitation of opinions, careful study, attracting, formed

39、 a revised sent reviewers. In October 8 and October 12, Central Committee Political Bureau Standing Committee and the Political Bureau of the Central Committee After consideration of the two regulations revised draft. On October 18, the Central Committee of the Communist Party of China formally issu

40、ed two regulations. Can say, two laws amendment concentrated the wisdom of the whole party, embodies the party. Second, and revision of the basic principles of two party regulations revision work and implement the partys eighteen, ten eight plenary, the spirit of the Fourth Plenary Session of the El

41、eventh Central Committee and General Secretary Xi Jinping important instructions on the revised and , highlighting the ruling party characteristics, serious discipline, the discipline quite in front of the law, based on the current, a long-term, advance as a whole, with Bu Xiuding independent and .

42、Main principle is: first, adhere to the party constitution to follow. The constitution about discipline and self-discipline required specific, awaken the party constitution of party compasses party consciousness, maintaining the authority of the constitution. General Secretary Xi Jinping pointed out

43、 that no rules, no side round. Party constitution is the fundamental law, the party must follow the general rules. In early 2015 held the eighth session of the Central Commission for Discipline Inspection Fifth Plenary Session of the 16th Central Committee, Xi Jinping again pointed out that constitu

44、tion is the party must follow the general rules, but also the general rules. the revision of the and is Method in adhere to the regulations established for the purpose of combining rule of virtue is to adhere to the party constitution as a fundamental to follow, the constitution authority set up, wa

45、ke up the party constitution and party rules the sense of discipline, the party constitution about discipline and self-discipline specific requirements. 4 second is to adhere to in accordance with the regulations governing the party and the party. The Party of rule of virtue de, mainly refers to the

46、 partys ideals and beliefs, excellent traditional style. The revised the closely linked to the self-discipline, insisting on the positive initiative, for all members, highlight the vital few, emphasized self-discipline, focusing on the morality, and the majority of Party members and the ideological and moral standards. The revised Ji method separately, Ji, Ji Yan