r淤泥質地層小關凈距隧道下穿建筑物施工關鍵技術

1、rapid development of the market economy environment to explore public servants duty consumption monetization reform has provided a good foundation. the socialization of rear service work has been launched, and rapid progress in some places and departments, duty consumption monetization of carrier an

2、d approach to management has been resolved. third, in recent years, exploring the monetization of duty consumption has made some progress, have gained some experience and can provide reference to the comprehensive reform of the system of public servants duty consumption further. implementing an hone

3、st canteen, standardize official entertaining management; enhancing the telecommunication expense management; elimination of county travel and countryside subsidies; research village officials capitalization management of corporate spending, and so on. finally, group .18 session to be held in beijin

4、g from november 9, 2013 to 12th. 35 years ago blew the third plenary session of the reform and opening up in the spring breeze, changed, affect the world; today, 35 years later, in the eyes of the nation and the world expect, again to reform mark china, ushered in the 18 session. xi general secretar

5、y pointed out that chinas reform has entered a crucial period and the sham shui po district, must be based on greater political courage and wisdom, lose no time in deepening reform in important fields. dares to crack a hard nut, dares to question the rapids, which dares to break the barrier of ideas

6、, and dare to benefit cure barriers. deepening reform and opening up is on schedule to achieve institutional safeguards of the moderately well-off. under the five in one the general layout of socialist modernization requirements, 18 session of the decision was a five in one and the improvement of ov

7、erall scheme of reform, will promote an integrated and coordinated economic, political, cultural, social and ecological civilization construction of the five reforms and the partys construction in the area of institutional reform. the five in one programme is to achieve a comprehensive reform of ins

8、titutional guarantees for objectives of build a well-off society, the smooth progress of the construction of a well-off society and reform the objectives of the programme. one, holding time and place importance on november 9, 2013 to the 18 session of the 12th beijing since 1978, 35, have been 7 ple

9、nary session, each time on major issues of political and economic life of the country has made important deployment. in accordance with prc political practice, often at every session of the cpc central committee in a plenary session was held immediately after the partys congress, on the theme person

10、nel, discussing election centrals top leaders, such as the election of the standing committee of the political bureau, through the central committee members, decisions, such as members of the central military commission. the second plenary session, is held in two sessions before the general election

11、, mainly to discuss a new state personnel issues. but by the third 淤泥質地層小凈距隧道下穿建筑物施工關鍵技術摘要：本文主要通過工程實例闡述淤泥質地層小凈距隧道下穿既有建筑物施工關鍵技術和控制要點。關鍵詞：淤泥質地層；小凈距隧道；下穿既有建筑物；關鍵技術abstract: this paper mainly through engineering examples of silt quality of a material of small interval tunnel in adjacent buildings under

12、construction key technology and control points.keywords: silt quality of a material layer; small interval tunnel; in both under buildings; key technology中圖分類號：tu74文獻標識碼：a 文章編號：0引言某地鐵區(qū)間隧道下穿既有地下通道段屬于多條小間距隧道并行穿越既有建筑物的工程類型。施工中以設計方案為依托，通過對施工工藝、支護參數進行調整改進，有效的控制了隧道結構及周邊建筑物沉降變形，工程如期順利完成，取得了良好的社會和環(huán)境效益。文獻1采用數

13、值模擬方法在理論上對群洞施工步序、步距的合理性進行了研究分析，文獻2-6根據工程實例提出群洞施工的合理工序和關鍵技術措施，文獻7-8分別采用數值模擬和現場實測的方法對群洞施工過程中洞內外沉降情況進行了分析總結，本文編寫過程中涉及的相應內容有所參考借鑒。1工程概況某地鐵區(qū)間隧道為分離式單線隧道，沿城市主干道下方布設，在距區(qū)間隧道東端頭65米位置設置一座臨時豎井和橫通道。橫通道以東段，由三條小間距隧道組成，分別為區(qū)間左、右線隧道及與其對接的地鐵車站站1號風道，三條隧道平行布置。三條隧道凈距34米，下穿既有過街道段長約為13.5米，隧道結構頂距離既有通道底板凈距1.2米。圖1隧道與過街通道相互關系剖

14、面圖2地質特點隧道穿越-2b4軟流塑地層。該地層富水飽和，蠕動性強，土層自穩(wěn)能力極差。開挖支護過程中極易發(fā)生涌泥、涌水、坍塌現象。原過街通道施工對地層已有干擾，破壞了原有軟流塑地層結構。正線隧道施工時屬二次擾動，地層應力釋放和重分布更為明顯，地層變形造成的沉降比其它地段更加敏感。在正線隧道施工完成后，進行1號風道施工時造成地層的再次擾動，地表以及建筑物沉降控制難度極大。3施工關鍵技術3.1超前大管棚施工圖2管棚施工示意圖原街通道圍護樁把該段隧道分成了過街通道以西、下穿過街通道段及過街通道以東三個部分，因此大管棚的施工也被分成三個循環(huán)區(qū)段（參見圖2）。3.1.1第一循環(huán)（過街通道以西段）利用已經

15、施工的橫通道空間施作第一循環(huán)大管棚，管棚直徑121，由于過街通道同隧道斜交，每一根管棚的長度都不一樣，同時考慮第二個循環(huán)管棚工作室的施工，按照最短的一根管棚來計算管棚施工的仰角，采取跟管鉆進工藝，終孔在過街通道西側圍護樁面。3.1.2第二循環(huán)（下穿過街通道段）利用管棚工作室從西往東鉆進施工，管棚直徑146，由于過街通道同隧道斜交，每一根管棚的長度都不一樣。采用金剛鉆頭開孔破過街通道西側的圍護樁，然后跟管鉆進，終孔在過街通道東側圍護樁面。隨后進行注漿。在施作管棚前采用鋼花管對通道下方碎石層進行注漿加固，提高碎石層和土層穩(wěn)定性，減小開挖對通道下1.2m土層破壞，并對通道底部含水碎石墊層施作引水鋼管

16、排水，該段初支完成后利用小導管徑向注漿對上方過街通道結構補漿回填，防止通道結構后期下沉，影響隧道和通道結構安全。3.1.3第三循環(huán)（過街通道以東段）受過街通道底板高度的限制，無法施作過街道以東段第三個循環(huán)大管棚的工作室。因此，第三個循環(huán)管棚沿用第二循環(huán)的工作室，對第二循環(huán)的146管棚采用巖心鉆掃孔、洗孔后，作為第三循環(huán)121管棚的導向管從中繼續(xù)往前鉆進布設，這樣既可以有效解決采取金剛鉆開孔穿過圍護樁并在穿孔后繼續(xù)采用跟管鉆進的問題，另一方面套管施工提高了下穿過街道段的管棚剛度。3.2 全斷面劈裂注漿為了有效控制注漿壓力對隧道結構、過街道及地表管線的影響，劈裂注漿采用hsc超細水泥漿。另采取多開

17、孔、小漿量的注漿工藝，通過加密掌子面布孔、減少單孔注漿量，以達到均勻改良地層、降低注漿壓力的效果。劈裂注漿孔的斷面布置情況見圖3。圖3 劈裂注漿布孔圖3.2.1注漿參數（見表1）3.2.2 漿液配比周邊孔采用超細水泥漿，該種漿液具有早強、高結實率、可注性強等特點，尤其在粉土、淤泥質等地層中有極好的滲透性，且對地層擾動較小。其余內圈孔仍采用普通水泥水玻璃雙液漿。超細水泥漿水灰比1：11.2，普通水泥漿水灰比1：1，水泥漿：水玻璃1：0.81，水玻璃稀釋濃度205be。3.2.3 注漿順序對原設計注漿順序進行調整。采取由外而內、自下而上的施工順序，每圈采取隔一注一的方式跳孔注漿。圖4劈裂注漿順序圖

18、3.2.4 注漿工藝1）采用30cm厚c20網噴混凝土止?jié){墻，6鋼筋網，網格間距1515cm，按普通噴混凝土工藝完成。2）采用鉆機成孔，鉆孔精度控制在1%以內。3）成孔后插入42mmpvc袖閥管。4）下管完成后，孔口50cm深度范圍內采用雙快水泥進行密封。凝固后，向注漿管內注入套殼料對管壁空隙進行填充，單孔注入0.51.0m3漿液，完成后用清水洗孔。5）待pvc管與孔壁之間固結體達到一定強度后，在pvc管內插入注漿芯管（含止?jié){塞）進行分段注漿。袖閥管管壁溢漿孔布設間距40cm，且用橡皮套包裹，注漿時壓力使?jié){液頂開橡皮套，進入土體產生劈裂效果，并沿著裂縫擴散，擴散范圍受注漿壓力、時間、漿液配比、

19、土層特征等因素的影響；停止注漿時，橡皮套再次收縮包裹溢漿孔，防止?jié){液倒流。6）采用后退式注漿，即從注漿管最底部開始注，邊注邊拔芯管，每次拔管長度1米。7）注漿完成后，清洗管內殘留漿液，以便于第二次重復注漿。8）按定量定壓相結合的原則，以定壓注漿為主來作為注漿結束標準：當注漿壓力穩(wěn)定上升，達到設計終壓；漿液注入量達到設計值80%以上，并持續(xù)穩(wěn)定10分鐘以上后，不進漿或進漿量很少時，即可停止注漿，進行封孔作業(yè)。3.3 洞內徑向注漿考慮1號風道開挖范圍內土體為淤泥質粉質粘土，且經左右線隧道施工擾動后產生液化。為降低風道施工對左右線隧道的影響，待左右線隧道初支施工完畢后，在隧道內對其周邊土體進行徑向注

20、漿加固，形成加固帷幕（見圖5）。圖5徑向加固注漿示意圖3.3.1注漿材料注漿管采用32無縫鋼管加工，l4m，頂端呈封閉尖錐狀；沿管身500mm間距梅花型布設逸漿孔，孔徑5mm，尾端1m不設孔；注漿管采用風鉆成孔后頂入，孔位環(huán)、縱向布設間距0.91.0m。3.3.2漿液配制漿液采用超細水泥單液漿，水灰比1：1。3.3.3 注漿控制及注漿結束標準徑向注漿以壓力作為注漿結束標準。注漿時，拱部注漿壓力宜控制在0.4mpa以內，邊墻注漿壓力控制在0.8mpa以內，防止壓力過大造成地表隆起及過街道結構變形。3.4下穿過街道段截樁施工在隧道開挖過程中須過街通道圍護樁進行破除。為防止破樁影響上部結構安全，保證

21、結構受力穩(wěn)定并達到快速施工目的，現場采用型鋼拱架代替格柵，型鋼緊貼密排，在破除樁體時形成連續(xù)縱梁結構，完成過街通道樁體受力轉換，防止破除樁體后發(fā)生樁底失穩(wěn)危及過街道安全。4施工監(jiān)測及結果評價施工期間隧道結構穩(wěn)定，未出現突泥、涌水、路面坍方等險情。地表及管線、地下過街道結構均穩(wěn)定，未發(fā)生隆起變形或開裂現象。施工期間監(jiān)測數據統計及分析如下：1)地表及管線沉降左、右線開挖過程中引起地表沉降最大值分別為49.3mm和39.1mm，點位均處于隧道中線上。風道開挖引起地表沉降最大值12.9mm，點位也處于風道中線上。供水管線最大沉降量為21.1mm。2)隧道內沉降、收斂及通道沉降群洞段開挖完成后，隧道內拱

22、頂最大沉降16.5mm，收斂1.14mm；地下過街道最大沉降量16mm。3)風道開挖期間，左右線隧道內沉降、收斂監(jiān)測數據未發(fā)生明顯變化，隧道結構穩(wěn)定。由此分析，各隧道開挖范圍內及周邊軟流塑地層經注漿加固、加強支護措施后，在開挖過程中的群洞效應明顯降低，結構變形均處于穩(wěn)定、可控狀態(tài)。而上層未加固的軟流塑地層經失水、施工擾動后發(fā)生蠕變、液化流動以重新達到平衡狀態(tài)，從而引起相對較大的地表沉降。若具備場地條件，能夠在路面上對隧道上層土體實施注漿加固，則地表沉降控制效果將更加理想。5結論與討論上述技術措施是建立在對淤泥質地層特性有一定的認知和了解的基礎上，同時結合施工中總結的經驗，對地層加固、管棚施工等

23、關鍵技術進行改良，并通過合理的施工組織安排，確保了隧道施工安全和周邊環(huán)境的安全正常，解決了軟流塑淤泥質地層小間距并行隧道近距離下穿既有建筑施工安全風險，取得了良好的經濟、社會和環(huán)境效益。1)管棚施工工藝改進通過對管棚施工工藝的改進，首先增強了下穿既有結構段的超前支護強度，較原設計的密排超前小導管支護措施有更可靠的安全性；其次，二次套打的121管棚在穿過既有結構底部后可直接延伸至開挖終點里程，代替了設計圖中的60中管棚施工，既增強了超前支護強度降低施工風險同時也節(jié)省了中管棚施工循環(huán)時間，加快了施工進度，具有一定的間接經濟效益。2)注漿工藝改良施工中采用了劈裂注漿和徑向加固注漿兩種不同的注漿工藝，

24、對這兩種工藝的改進主要是基于有效控制注漿壓力，防止造成既有建筑物、已成型隧道開裂變形的目的。采用超細水泥漿代替普通水泥-水玻璃漿液很大程度上增加了成本的投入，但地層加固的效果有了明顯提高，施工過程中對周邊環(huán)境的影響也得到了很好的控制，具有良好的社會和環(huán)境效益?！咀髡吆喗椤拷靿q（1975年5月），安徽黃山人，工程師，現工作于中鐵隧道集團二處有限公司，主要從事城市地鐵工程施工管理。參考文獻1 莊寧，廖少明，孫忠成等.大跨度小凈距群洞隧道施工方案優(yōu)化研究j.地下空間與工程學報.96-100。2 楊宏射.地鐵淺埋群洞施工工序與關鍵技術j.城市軌道交通研究.70-72。3 郭龍，劉牧宇.淺埋暗挖群洞法

25、施工中結構受力的合理轉換j.鐵道建筑.25-27。4 仝學讓.淺埋大跨度群洞隧道施工技術j.安徽建筑.92-94。5 陳世權，王俊生.小凈距大跨度隧道的施工技術j.工程質量.35-38。6 董惠定，李兆平.北京地鐵車站暗挖施工方法比較與評述j.現代隧道技術,2004年增刊：101-105.7 劉成偉，劉招偉，余永強.某地鐵車站群洞法施工地表沉降監(jiān)測分析j.西部探礦工程.138-140。8 余永強，文廣超.地鐵車站“群洞法”施工對地表沉降影響的數值模擬j.華東公路.84-87。注：文章內所有公式及圖表請以pdf形式查看。plenary session, each session of the c

26、entral committee of national institutions and personnel problems have been arranged, you can concentrate on national development and reforms. previous plenary session is often branded with a central leading collective, often by looking at the third plenum of the initiative to found the current centr

27、al leadership collective governance characteristics. from the analysis of the process of economic reform in china, plenary session, 12 session, 14, 16 plenary session have programmatic meaning, respectively, marking the four stages of chinas economic reform, and that the start-up phase of reform, re

28、form, construction phase and perfecting the socialist market economy framework stage of socialist market economy. previous plenary session topics proposed to the third plenary session of taking class struggle as the key link, shifted to socialist modernization; 12 session marked the change from rura

29、l to urban, established with public ownership as the foundation of a planned commodity economy; 13 session at a time when both the old and the new system change, governance and rectify the economic order; 14 . fair and efficient and authoritative socialist judicial system, safeguard the peoples inte

30、rests. legal authority to uphold the constitution, deepening the reform of administrative law enforcement, ensure that the right to exercise judicial power independently and impartially according to law the prosecution, perfecting the running mechanism of judicial power, improve the system of judici

31、al protection of human rights. plenary session, affairs the right to adhere to the system, and let the people authority to let the power run in the sun, is shut up in a cage of the system power policy. decision science, implementation should be constructed strong, supervise the running of powerful system, improve the system of punishing and preventing corruption, promoting political integrity, and strive to achieve cadres honest and government