大管棚超前支护技术在武隆隧道洞口浅埋段施工中的应用.doc

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1、【精品文档】如有侵权，请联系网站删除，仅供学习与交流大管棚超前支护技术在武隆隧道洞口浅埋段施工中的应用.精品文档.大管棚超前支护技术在武隆隧道洞口浅埋段施工中的应用摘要：武隆隧道进口下穿武仙公路段埋深较浅，隧道施工对既有武仙公路影响较大。针对这种情况，采用大管棚超前支护施工方法，使隧道顺利穿越武仙公路进洞。本文主要从施工技术角度阐述大管棚超前支护技术在隧道洞口浅埋段施工中的应用。关键词：隧道； 大管棚超前支护；注浆；效果1工程概况武隆隧道位于重庆市武隆县巷口镇附近，隧道全长4884.1双延米，隧道设计为净宽10.79m，净高7.00m的三心圆曲墙半圆拱。隧道进口端洞口基岩出露为页岩、砂岩，局部

2、夹灰褐色泥岩、粘土岩，质极软。隧道进口下穿武仙公路挖方路基段隧道设计标高269.65m，武仙公路设计标高282.65m，隧道拱顶距武仙公路路面4.16m，约0.3D（D：隧道开挖跨径，为13.28m），隧道施工对既有武仙公路影响严重。2大管棚超前支护的必要性及相关的工作原理由于隧道开挖断面大，洞口处岩体风化十分严重，土体松散，加之上方武仙公路的影响，洞口开挖面极易发生坍塌，施工进洞困难。采用大管棚超前支护施工技术对洞口段堆积体进行注浆固结然后再开挖，这样可以有效保证洞口边仰坡稳定，而且使开挖轮廓线外圈形成棚幕和一层壳体，从而大大增加了进洞施工的安全性，确保顺利进洞及武仙公路的安全。 超前支护的

3、基本工作原理是在待开挖洞顶轮廓线以外一定角度范围内，环向按照一定的间距超前打入钢管，并在钢管内进行压力注浆。环向钢管形成棚架，为开挖及初期支护作业提供了安全保障；浆液固结后钢管和围岩之间组成了一个共同的固结圈，从而在隧道的纵向和横向分别形成一个刚度较大的梁结构和拱结构。这个结构能有效提高围岩的承载力及自稳能力，减小围岩的变形；同时，隧道开挖后与钢架一起共同组成刚度较大的支护结构，以抵挡隧道开挖后产生的围岩压力和变形。3大管棚超前支护设计参数钢管规格：采用127mm壁厚4.5mm的热轧无缝钢管，钢管前端呈锥形，尾部焊接10加劲箍筋，管壁四周钻2排20mm压浆孔，管长30m.，钢管内设置钢筋笼，钢

4、筋笼主筋420，采用50壁厚4.5mm的钢环作固定环，固定环节长4cm，与钢筋笼主筋焊接，如图1所示：管距：环向间距为40cm，共布置35根；外插角：1。管棚注浆采用M30水泥砂浆，水灰比为1：1。图1 钢管大样图 4大管棚施工及相关技术要求大管棚施工工艺流程如图2。图2 大管棚施工工艺流程图4.1 施工前的准备工作4.1.1 套拱施作待暗洞口边仰坡加固稳定后，施作套拱，套拱开挖不得再随意切坡，只有在管棚施作完毕后，才能扩挖。在管棚施工中，必须保持套拱的稳定，不偏移，不沉降，必要时增加一些临时支撑，以确保管棚施工安全和孔口管就位准确。C25混凝土套拱作为管棚的固定端，拱内设两榀18工字钢，在其

5、中用16固定钢筋焊接布置35个150孔口管，孔口管与18工字钢焊为整体。4.1.2 钢管制作钢管按照设计要求制作，管口加工成锥形以便送入，为确保接头质量，以长15cm的丝扣连接，起连接和导向的作用。为防止浆液倒流，每根钢花管尾部均焊接有止浆板，止浆板采用2cm厚钢板制作，中间钻有20带螺纹的眼，以备注浆时用。4.2 管棚的施作4.2.1钻孔利用孔口管并按设计角度为1的外插角把套管与钻杆同时同步冲击回转钻入岩土层内至设计深度。套管与钻具同时跟进，产生护孔作用，避免钻杆在提出孔后产生塌孔或涌水事故，并提供临时护孔，方便往孔内插管注浆。钻孔要求精度高，终孔位置准确，各开孔的孔眼与终孔的孔眼落在同一周

6、界面上，避免产生较大的偏差和变形。同时要确保钻孔的同轴度，以避免管棚送入时受卡。4.2.2 清孔钻孔结束后，先把套管内孔注水洗净后，再把钻杆取出。套管仍保留在孔内提供护孔作用。4.2.3 顶进钢管棚 把按设计要求加工好的钢管顶入套管内，接头采用 15cm 长的厚壁管箍，上满丝扣；并把钢管轻轻打入岩土层内，以固定钢管不易滑出孔口。钢管插进完毕后，取出套管。套管取出时，冒落的岩土会于孔内压紧钢管。钢管口与孔口周壁用水泥密封。当管棚安装完毕后，用小木楔把钢管与围岩壁楔紧，再用防水胶泥（锚固剂）将空隙封闭住。4.2.4插入钢筋笼 再次清孔并将钢筋笼插入钢管内，使之与钢管成为一体。4.3 注浆 利用浆液

7、的渗透作用和压密作用将周围岩体预先加固并封堵围岩的裂隙水，这样既能起到超前预支护的作用，同时也增强了管棚的强度和刚度。注浆的技术要求：注浆时一般由两侧低位孔向中间高位孔顺序向上进行，先注无水孔，后注有水孔。注浆结束的条件：单孔结束条件：注浆压力达到设计终压，浆液注入量已达到计算值的80以上；全地段结束条件：所有注浆孔均已符合单孔结束条件，无漏注浆的情况。注浆过程中应时刻注意观察注浆管周围防水胶泥的变化情况，防止浆液压力增加时将其冲裂。注浆过程中随时检查孔口、邻孔有无串浆现象，如发生串浆，应立即停止注浆或采用间歇式注浆封堵串浆口，也可采用木楔、快硬水泥砂浆或锚固剂封堵，直至不再串浆时再继续注浆。

8、注浆过程中压力如突然升高，可能发生堵管，应停机检查。5施工效果检测与评价对注浆加固区进行钻芯取样，浆液的填充情况良好。钻爆开挖后开挖断面检测结果符合设计及规范要求。武仙公路路面沉降监测结果符合设计要求。对洞口段的收敛变形、拱顶下沉、边坡位移、拱圈位移、锚杆受力、钢拱架及钢筋网应力等进行了全面的监测。监测结果表明：布设监测点的断面基本处于稳定状态，能够满足设计和规范要求。6结语通过工程实践证明，大管棚工法的梁效应和固结效应既能阻止松散围岩的坍塌又能有效控制沉降。大管棚超前支护在武隆隧道下穿武仙公路的洞口浅埋段施工中的成功应用为隧道施工及武仙公路的安全奠定了基础，也为后续软弱围岩的处理及复杂地质条

9、件下的洞身施工积累了经验。参考文献1 JTJ 04294，公路隧道施工技术规范S2 黄成光主编.公路隧道施工技术M.北京:人民交通出版社.2001（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 r

10、ules 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, focusing on morality is of Party members and Party leading cadres can see, enough to get a high standard; around the party d

11、iscipline, 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 regulatio

12、ns 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

13、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 Communist Party members and leading cadres honest politics several guidelines and column 1 by 2015 to strengthen party laws

14、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

15、 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 the eighth session of the third, the spirit of the fourth plenary session, reflecting the experience of studying and impleme

16、nting the General Secretary Xi Jinping series of important speech, reflects the partys eighteen years comprehensive strictly practice. (a) revised two regulations of the party need of in based on revised, the promulgation and implementation of January 2010, to strengthen the construction of the cont

17、ingent 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 practi

18、ce; 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

19、 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 2003 the promulgation and implementation, to strengthen the construction of the party play very important role. Along with t

20、he 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 reg

21、ulations 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 si

22、tuation, 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 tree and call up the majority of Party members and cadres of the party constitution of party compasses party consciousness.

23、(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

24、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 Wan

25、g 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 Com

26、mission, 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,

27、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 peopl

28、e 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 Poli

29、tical 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, an

30、d 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 Eleventh Central Committee and General Secretary Xi Jinping important instructions on the revised and , highlighting the rul

31、ing 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 . Main principle is: first, adhere to the party constitution to follow. The constitution about discipline and self-disciplin

32、e 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 earl

33、y 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 and is Method in adhere t

34、o 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-dis

35、cipline 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 partys ideals and beliefs, excellent traditional style. The revised the closely linked to the self-discipline, insisting

36、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 heteronom

37、y, 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 an

38、d 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 partys eighteen years strict political discipline and p

39、olitical 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 revisi

40、on of major changes, major changes in the and modified and needs to grasp several key problems (a) 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

41、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

42、 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 . Three is for all the party members, will apply object from the leadership of the party members and cadres to expa

43、nd 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,

44、 easy to understand, easy to remember. The revised 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 Peoples solemn commitment. criterion of a clean and honest a

45、dministration consists of 4 parts, 18, more than 3600 words. After the revision of the , 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

46、 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

47、 the partys 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 leader cadre clean fingered self-discipline norms for the leadership of the party members and cadres of the vital