zr沉管灌注桩施工工艺与机型.doc

【精品文档】如有侵权，请联系网站删除，仅供学习与交流zr沉管灌注桩施工工艺与机型发布时间：2006-2-24 12:28:52   点击次数：3283次1概况中国航天总公司某科研楼，由中国航天第七设计研究院设计，为8层框剪结构，独立柱下振动冲击沉管灌注桩基础。原设计桩径500 mm，桩长22 m，通长配筋，单桩承载力标准值1000 kN，单柱荷重9000 kN。四川省建筑科学研究院考虑此项工程桩基的荷载、桩长、施工难度在四川乃至西南地区均属首位，于是推荐由我公司承建。我公司考虑到该地层为第四系更新统硬塑坚硬塑粘性土和桩的特点为端承摩擦桩，经论证及设计院同意后改为400 mm复打桩，桩长18.0 m，单桩承载力要求不变，并要求先打试桩，经静载试验满足要求后，方可根据有关参数进行工程桩施工。经试桩，静载确定桩为ZG400B型复打桩，桩长18.0 m，复打深度12.5 m，钢筋笼长11.60 m，桩数237根。2满足设计承载力的成桩模型和理论计算2.1成桩模型采用400 mm局部复打成桩的理论模型见图1。图1局部复打长桩成桩理论示意图图2按物理参数计算示意图(2)按物理参数及电流电压控制计算：Quk=Qsk+QpkQpk与电流冲击力、电流电压有关，可用经验公式p=kI代入(p为一定电压下，一定电流产生的冲击力；k为经验系数，一般取10；I为锤头工作时最后30 s的电流值，此处为100)。经计算Qsk=1606.11 kN，Quk=2602.11 kN，则单桩承载力标准值为1303.06 kN，满足设计要求(1000 kN)。3桩机选型在确定该工艺施工之前，我公司设计论证过其它桩的工艺施工，如钻孔桩、挖孔桩等，但因经济、技术等指标难于达到要求而未被采用。最后对比最多的是预制桩，预制桩同灌注桩一样，在西南地区多属小直径桩；因灌注桩是就地灌注混凝土，不需裁桩和接桩，可节省混凝土，只配少量钢筋，可节约钢材2/36/7；且减少预制构件的场外运输，比预制桩节约工程费用30%40%。另外，也是最重要的一点，该工程桩是端承摩擦桩，预制桩不能取土引孔，遇上较厚的硬塑坚硬粘性土层不能穿过，达不到设计桩长要求。沉管灌注桩能达到此要求，故选用沉管灌注桩施工工艺。沉管灌注桩机型按大类分为DZKS型和DZC型两类，代表主要为DZ60KS型和DZC44型，由主要技术参数比较，DZ60KS型有利于长桩施工，特别是许用拔桩力和沉桩最大长度均优于DZC44型，在实践中也已得到证实。按通长配筋考虑，DZC44型沉桩长度最多12 m，且无中孔(锤头中部的圆孔)；而DZ60KS型具有500 mm中孔，钢筋笼可以从锤头上部往下吊，沉桩长度可达25 m左右。从经济、技术综合考虑，选择了沉管灌注桩，再从机器设备的主要技术参数、实践经验及各参数的优化组合等方面的分析论证，认为DZ60KS型沉管灌注桩机施工该项工程是可行的。4施工工艺的重点与难点4.1解决取土难的措施该工程需引孔取土，成桩要穿越10.013.0 m厚的硬塑坚硬塑粘性土，加之桩长、桩径大，摩阻力大，造成取土难。经分析，采取了分段取土减小摩阻力的方法。一般为多次取土，每次取土14 m，一孔取完最多达11次，在取土过程中并以电流、电压值不超过80 A、380 V或最后贯入度5 cm/min，来具体控制取土深度，从而克服了强行加压取土，减少对机器设备的损坏，达到设计桩长。4.2解决抖土难的理论模型及桩内夹泥的措施取出的土在桩管内，因粘性土与桩管内壁间摩阻力大，且具粘附力，所以很难抖出，影响下一段取土。我们采取重锤下落、加水形成水压力等方法，但效果均很差。最后，利用滑坡产生机理解决了此项难题。其原理是：在取土之前加入水，水在取土过程中随土体上升，沿土体与桩管内壁孔隙下渗，使桩管内壁与土体间形成相对软弱缝，取出土后，土块沿该缝在开启锤头振动的周期性外力作用下产生滑落，此法简称加水润滑，在实际施工过程中，取土之前在桩管内加入45桶水，从而使每次抖土时间由45 h减少到510 min。同理，在桩管外壁加水12桶，使桩管外壁粘附泥块滑落，并在拔管时采用人工刮土方法清除外壁泥块，从而避免了桩内夹泥，保证了施工质量。4.3桩尖偏向及解决措施由于多次取土，加之用450 mm取土器扩孔，孔径增大，桩尖在下落过程中易偏向斜卧或横卧于孔中，影响沉管深度，我们采用钢绳吊放桩尖使其紧贴桩管端部后再沉管，从而解决了偏向问题，保证了沉管深度。4.4混凝土坍落度的调整如果按常规的混凝土坍落度，因桩长，振动拔管时间长，很难满足桩密实、桩强度和沉管深度要求。其中关键一点是影响复打深度。经试验，第一次混凝土坍落度大，在复打过程中，因桩间土为坚硬、硬塑粘性土，排水条件差，在长时间振动下，粗骨料多下沉，造成局部密实，阻力增大，复打深度难于满足。最后确定第一次混凝土坍落度810 cm，确保了复打深度，第二次混凝土坍落度1214 cm，以利混凝土密实及桩身完整。5结语(1)取土速度快，抖土顺利，成桩工艺新颖实用，成桩效率提高34倍，实际施工80天，工期比原定提前40天。(2)满足了设计桩长18.0 m、复打12.5 m的要求，最深复打15.8 m。(3)桩身密实，结构完整，无断裂、夹泥、缩径等质量缺陷，桩强度达到C25的设计要求，桩径在485520 mm之间。同时，经高应变力法测试，单桩承载力标准值为10201080 kN，满足设计单桩承载力1000 kN的要求。(4)该工程经设计、建设、总包、质监等部门一次性验收，评为优良。(5)该工程的成功实施，较原设计节约钢筋混凝土188.496 m3，节约基建投资17万元。同时为我公司节约设备维修费5万余元，经济效益和社会效益明显。振动冲击沉管灌注桩施工规程和技术资料汇编.四川省建筑科学研究院，1986.作者简介：彭勇：原冶金部西南勘察基础总公司八公司。地址：610212 成都市外东中和。6参考文献1建筑桩基技术规范(JGJ94-94).北京：中国建筑工业出版社，1995.2岩土工程勘察规范(GB50021-94).3混凝土强度检验评定标准(GBJ107-87).北京：中国计划出版社，1988.精品文档.沉管灌注桩在长桩、大承载力桩基础施工中的应用（英文版 ） Two regulations promulgated for implementation is in the party in power for a long time and the rule 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 < code > adhere to a positive advocate, focusing on morality is of Party members and Party leading cadres can see, enough to get a high standard; < rule > 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 ". Here, 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 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. < code > and < Regulations > revised the necessity and revised history of the CPC Central Committee the amendment to the Chinese Communist Party members and leading cadres honest politics several guidelines > and < Chinese Communist Party discipline and Punishment Regulations > 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 the wisdom of our predecessors, which reflects the unity of inheritance and innovation; follow the correct direction, grasp the limited goals, adhere to the party's leadership, to solve the masses of the people reflect a focus on the problem. The new revision of the < code > and < rule >, reflects the party's 18 and the 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 party's eighteen years comprehensive strictly practice. (a) revised two regulations of the party need of < the ICAC guidelines > in < in 1997 Leaders as members of the Communist Party of China clean politics certain criteria (Trial) > 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. Content 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 the 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. < rule > is in 1997 < Chinese Communist Party disciplinary cases (Trial) > based on revision, in December 2003 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 of 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 responsibility to pursue; third is the main discipline for the leading cadres, does not cover all Party members. Based on the above situation, need to < the criterion of a clean and honest administration > and < rule > 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 tree 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 books 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 regulations 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 forum 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 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 commissions, 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 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 issued two regulations. Can say, two laws amendment concentrated the wisdom of the whole party, embodies the party. Second, < code > and < Regulations > revision of the basic principles of two party regulations revision work and implement the party's eighteen, ten eight plenary, the spirit of the Fourth Plenary Session of the Eleventh Central Committee and General Secretary Xi Jinping important instructions on the revised < low political criterion > and < Regulations >, 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 < rule > and < rule >. 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 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 constitution is the party must follow the general rules, but also the general rules." the revision of the < code > and < rule > 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, wake 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 party's ideals and beliefs, excellent traditional style. The revised the < code > 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 to Method, as a "negative list", emphasizing the heteronomy, focusing on vertical gauge. Is this one high and one low, a positive reaction, the strict party discipline and practice results transformation for the integration of the whole party to observe moral and discipline requirements, for the majority of Party members and cadres provides benchmarking and ruler. Third, insist on to. In view of the problems existing in the party at the present stage, the main problems of Party members and cadres in the aspect of self-discipline and abide by the discipline to make clearly defined, especially the party's eighteen years strict political discipline and political rules, organization and discipline and to implement the central eight provisions of the spirit against the four winds and other requirements into Disciplinary provisions. Not one pace reachs the designated position, focusing on in line with reality, pragmatic and effective. After the revision of major changes, major changes in the < code > and < rule > modified and needs to grasp several key problems (a) < code > < code > adhere to according to regulations governing the party and party with morals in combination, for at the present stage, the leadership of the party members and cadres and Party members in existing main problems of self-discipline, put forward principles, requirements and specifications, showing Communists noble moral pursuit, reflected at all times and in all over the world ethics from high from low 5 common requirements. One is closely linked to the "self-discipline", removal and no direct relation to the provisions of . the second is adhere to a positive advocate, "eight prohibition" 52 are not allowed to "about the content of the" negative list moved into synchronization amendment < cases >. Three is for all the party members, will apply object from the leadership of the party members and cadres to expand to all Party members, fully embodies the comprehensive strictly required. The fourth is prominent key minority, seize the leadership of the party members and cadres is the key, and put forward higher requirements than the ordinary Party members. Five is to simplify, and strive to achieve concise, easy to understand, easy to remember. The revised < code > is the ruling Party since the first insists on a positive advocate forAll Party members and the self-discipline norms, moral declaration issued to all members of the party and the National People's solemn commitment. > < criterion of a clean and honest administration consists of 4 parts, 18, more than 3600 words. After the revision of the < code >, a total of eight, 281 words, including lead, specification and Party member cadre clean fingered self-discipline norms, etc. Part 3 members low-cost clean and self-discipline, the main contents can be summarized as "four must" "eight code". Lead part, reiterated on ideal and faith, fundamental purpose, the fine traditions and work style, noble sentiments, such as "four must" the principle of requirements, strong tone of self-discipline, The higher request for 6 and supervised tenet, the foothold in permanent Bao the party's advanced nature and purity, to reflect the revised standards requirements. Members of self-discipline norms around the party members how to correctly treat and deal with the "public and private", "cheap and rot" thrifty and extravagance "bitter music", put forward the "four norms". Party lea