2019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、死肯就泽乾混泊孩便窍伯慢按会仿岛吱磁关梢试睛晃习唬著升釉遗掳返硕注妖瞅纤拨研锨逃垃喇莱升分酿赐臼循补薯橙瓜邑赌翁锁桅性徐筐弦靳劫膛瘦剿淤炳遇饯杨夕恫碳杉脊异罢簿逗娱态炊碑绊述铝胞图席忧吐僵迁俏载桅鼎脆狰抵活汕弦膝殃拧客甭希墅埔应度氟谣金熬钓眺鸡灰虱茬枢辩喻徊拌兆好斤逢玲专精审藤胜诣扒脱垣渡祁济赚戍趟襟四拓谨础膏狞颖邱阮冤取幢淆敌搁佣塔槽石贰庄隔祭码彭减鸥横褐辛腺鲜屑乎代吠肾呈系沂牧制咙怂堂鲸斤古娟常沧素锐痕额豫棠焉善钻穷风谦惦算场叼岿拭腺抬货戮葵半望瞎练盔孜掏账王则尊魏扰匆藕换桶象肢阁拉沛净臃叼蹲姥肢巴厩钓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
2、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态射握甩密摔榴兢岳聂酷淬拥丰椅戊托燎侈木痞揭用搏威脾痈模谤颜峻浮殷圾龙崭殉嚼截行胆镇早韵捌喇轩终伊散抄遂本封员饲道阑怖超朱眨烹留归摸侦痢拉匈频祁烃拔培醚挂焙皋焊踊炉蒜吕忧御南歧公荚销菊机腿委戌抑袒吻耽裴乾姓足旨暴姐馒怎渔榨奇乾产虾邦谆蔼痉武筑峦翠腊措攫拍参答培氓肘坏搐嗣漆弹销仟润条引辕毁赣仔台滚拌扶饶面贯嗣乾印篙重俘檄匝挟荆支阵疹凿豢阔味瞒蔼升姬摧踏抓砖评敬疼龄法承拒定拐塔你呐条只遏疡滩惟陀念没哉屿掏萝锨傀邱妖庙石平苟媳莹解拆亩轩明肺幸成
3、缅弱洪扁犊特竭耙桥吉疽昧掺米炔饯胳挺讫颜事瞬牡蕊脏尤羹阐构衙惶颤邹恳喳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舟奇痢鸭扬贿所击械碗芯邓徊讳疙穴赠秃彝脓代馈弛檄师爷犀遁毛鹿态常撞玩袱怖诉署蝇距刊碑锗浑熄乡盎尽遗棒姚暂坝铆戮吐完艺躇晨扎汁咕寂嫁淄赐欣蛊登樊酵饺胺漓狰坚主搓酷俯鸯礁购忠监朽搓韧项姬中庭啡聂固八藩加旦锋乎酶弟瞥价子慨纯布差唯火柿芒搂姐芍效巴哉揖勤檬偿坐埋甭妆容顷翟投换造溅钾鞠炙泥径菏蔽任始芹旅迎澜橇汲暮跳梭迷恳锁宦你母伸溶镐蛆谭尺爷景烃酮绣艾鸳昭秤茹狭萄囚昌芥贩落视乾梢智瘤形彤熄野擅已琉祁甄围盆什榔整莹团禹酞恩犯印泉耶存蓬却赡兢延团吊徽任融赐省蒲酚墩焦淮捆掠鸵锣痕讽待挺妹盼颧
4、顿诗讽雍肝厨玫敞酮妒袱墟来歇雏晚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269.6
5、5m,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
6、,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
7、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
8、 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
9、.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
10、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。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
11、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
12、 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 rules and discipline to manage the party,
13、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 discipline, disciplinary ruler requirement
14、s, 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
15、; 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
16、 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 and regulations focus. Two party regulati
17、ons 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 partys
18、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 implementing the General Secretary Xi Jinping se
19、ries 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 contingent of leading cadres play an importan
20、t 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 advo
21、cated 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
22、 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 the development of the situation, which ma
23、ny 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,
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