軟土盾構(gòu)隧道縱向設(shè)計綜述

1、軟土盾構(gòu)隧道縱向設(shè)計綜述-摘要:通過對軟土盾構(gòu)隧道結(jié)構(gòu)設(shè)計理論的現(xiàn)狀和已建軟土盾構(gòu)隧道結(jié)構(gòu)存在問題的分析,指出克服軟土盾構(gòu)隧道結(jié)構(gòu)發(fā)生過量縱向沉降或不均勻沉降而引起隧道滲水、漏泥、結(jié)構(gòu)局部破壞等影響隧道正常使用及其耐久性問題的關(guān)鍵是展開縱向設(shè)計理論研究。在縱向設(shè)計理論指導(dǎo)下,通過軟土盾構(gòu)隧道襯砌管片拼裝形式、管片材料等方面的創(chuàng)新改造,使軟土盾構(gòu)隧道的設(shè)計方法更加科學(xué)合理。關(guān)鍵詞:軟土;盾構(gòu)隧道;縱向設(shè)計;地下工程1概述隨著世界經(jīng)濟的全球化和社會的不斷進步,人們對自身的生存環(huán)境質(zhì)量的要求愈來愈高,致使城市化水平迅速提高,城市規(guī)模不斷擴大。城市成為世界各國、各地區(qū)的政治、經(jīng)濟、文化發(fā)展中心。然而,

2、為城市建設(shè)的可持續(xù)發(fā)展、資源的節(jié)約和環(huán)境的保護,城市建設(shè)者越來越多地開發(fā)利用一切可以利用的有限生存空間,尤其是城市的地下空間,以建設(shè)給水、排水、能源、交通等地下隧道。然而,隨著地下空間的開發(fā)利用,越來越多的地下結(jié)構(gòu)由于使用過程中的過量不均勻變形而致的對地下結(jié)構(gòu)本身及其周圍環(huán)境的影響也愈加嚴(yán)重12。例如,在地下動水壓力的作用下,上海市金山海水引水工程中的盾構(gòu)隧道(見圖1)下臥土層的水土流入隧道,隧道隨之產(chǎn)生縱向沉降和彎曲,導(dǎo)致環(huán)向接縫進一步張開和水土流失增加,最終導(dǎo)致破壞性縱向變形和破壞性橫向受力狀態(tài),最大相對不均勻沉降達到了18,橫向直徑變化最大超過103。上海市地鐵一號線于1995年4月正式

3、建成投入運營。經(jīng)過長期的變形監(jiān)測發(fā)現(xiàn),隧道在長期運營中的沉降及不均勻沉降相當(dāng)大,許多隧道段的沉降和不均勻沉降一直在發(fā)展,而且沒有收斂的趨勢4。至2001年底人民廣場站-新閘路站之間的區(qū)間隧道最大累計沉降量超過200;黃陂南路站-人民廣場站之間的區(qū)間隧道差異沉降量近100(詳見圖2)。過大的不均勻變形已對隧道的結(jié)構(gòu)、接頭防水構(gòu)成威脅。到目前為止,雖然管片遭到破壞的情況極少,但在一號線已發(fā)現(xiàn)道床與管片之間發(fā)生開裂現(xiàn)象,在漢中路站至黃陂南路站之間已經(jīng)發(fā)現(xiàn)至少5處整體道床與管片之間發(fā)生開裂和脫節(jié)現(xiàn)象,斷斷續(xù)續(xù)累計達300。經(jīng)過調(diào)查發(fā)現(xiàn),基本上都是由于隧道局部較大的不均勻沉降造成5。另外由于縱向不均勻變

4、形造成管片接縫變形增大,一號線的區(qū)間隧道滲漏水的地方很多,漏水點主要集中在環(huán)縫、封頂塊相連的“十字縫”等處,而環(huán)縫漏水是最難處理的。隨著隧道縱向不均勻變形的發(fā)展,隧道漏水的情況越來越多,甚至?xí)绊懙罔F的正常運營。當(dāng)前大量地下隧道建設(shè)實踐中,盾構(gòu)施工法已成為城市地下隧道建設(shè)的主要施工方法,尤其地鐵隧道。上?，F(xiàn)有和正建的地鐵隧道無一例外地采用這一方法施工。而上海同許多沿海城市一樣是位于軟土廣泛分布的地層上,正是盾構(gòu)隧道結(jié)構(gòu)所處的軟土環(huán)境導(dǎo)致大量的運營軟土盾構(gòu)隧道發(fā)生過量的縱向沉降或不均勻沉降,引起隧道滲水、漏泥或結(jié)構(gòu)局部破壞,有時甚至?xí)绊懙剿淼赖恼＿\營2021。因此,深入研究軟土盾構(gòu)隧道縱向變

5、形對隧道結(jié)構(gòu)影響及考慮縱向變形的襯砌結(jié)構(gòu)縱向設(shè)計理論是解決軟土盾構(gòu)隧道現(xiàn)存問題的關(guān)鍵,尤其是襯砌結(jié)構(gòu)縱向設(shè)計方法。2襯砌結(jié)構(gòu)縱向設(shè)計現(xiàn)狀目前,國內(nèi)外對盾構(gòu)法隧道襯砌結(jié)構(gòu)設(shè)計主要采用橫向設(shè)計。在國內(nèi),我國地下鐵道及鐵路隧道設(shè)計規(guī)范6中推薦使用荷載結(jié)構(gòu)模型,而未考慮縱向變形的影響。上海市地基基礎(chǔ)設(shè)計規(guī)范1999版中對盾構(gòu)隧道縱向變形進行了一定的考慮7,提出盾構(gòu)隧道縱向不均勻沉降的影響是不可忽視的。尤其是盾構(gòu)工作井和區(qū)間隧道的連接處;隧道底部下臥土層特性及分層突變處;覆土厚度急劇改變處等,都會有較明顯的不均勻沉降。提出在設(shè)計中應(yīng)按照預(yù)估的沉降差,設(shè)置適量的變形縫。規(guī)范還提到在施工階段和使用階段,進行

6、隧道結(jié)構(gòu)的橫向內(nèi)力和變形計算時,在必要的時候宜考慮隧道縱向變形對橫向內(nèi)力和變形值的影響。目前,國內(nèi)針對軟土盾構(gòu)法隧道采用的設(shè)計模型主要為勻質(zhì)圓環(huán)和彈性鉸法1317,皆可用彈性方程解。前者主要用于使用階段的設(shè)計驗算,后者主要用于施工階段的設(shè)計驗算。在國外,國際隧道協(xié)會()在1978年成立了隧道結(jié)構(gòu)模型研究組,收集各會員國采用的地下結(jié)構(gòu)設(shè)計模型。并于2000年編寫出了盾構(gòu)隧道襯砌設(shè)計指南8,為各國盾構(gòu)隧道結(jié)構(gòu)的設(shè)計指明了基本原則。其中將結(jié)構(gòu)模型分為四類:連續(xù)體或不連續(xù)體模型、作用與反作用模型、收斂-約束模型和工程類比法。這與我國學(xué)者劉建航、侯學(xué)淵5的分類(經(jīng)驗類比模型;荷載結(jié)構(gòu)模型;地層結(jié)構(gòu)模型;

7、收斂限制模型)基本相同。同時在盾構(gòu)法隧道設(shè)計指導(dǎo)中提出在必要時將隧道縱向沉降的影響列入荷載類別的特殊荷載項予以考慮。美國交通運輸研究協(xié)會在2000年度報告9中就提到,很多處于軟土中的隧道、管道的破壞或出現(xiàn)問題就是由于縱向不均勻沉降而產(chǎn)生的。最多的一種情況就是由于下臥土層土性沿縱向分布不均勻而產(chǎn)生的縱向不均勻沉降。因此美國交通運輸研究協(xié)會在2000年提出了隧道“縱向設(shè)計”的概念,并計劃開始進行這方面的研究工作。由此可見,在現(xiàn)行的設(shè)計規(guī)范中還沒有縱向設(shè)計的相關(guān)內(nèi)容,但是,結(jié)構(gòu)的縱向問題對結(jié)構(gòu)的影響已經(jīng)引起廣大學(xué)者關(guān)注。因此,開展縱向設(shè)計相關(guān)研究具有重大現(xiàn)實意義。免費論文下載中心 由于隧道縱向問題屬

8、于三維問題,其結(jié)構(gòu)復(fù)雜,縱向結(jié)構(gòu)計算模型尚不成熟。但也已經(jīng)取得了一定的科研成果。在工程實測和室內(nèi)試驗基礎(chǔ)上,已建立了一些隧道縱向結(jié)構(gòu)計算模型。目前對軟土隧道縱向結(jié)構(gòu)的理論研究主要分為:試驗或?qū)崪y分析法、數(shù)值分析法和理論解析法。在理論解析法中根據(jù)隧道接縫和螺栓簡化方法的不同,日本學(xué)者提出了兩種隧道縱向結(jié)構(gòu)理論,一種是以村上博智及小泉淳22為代表的以軸向、剪切和彎曲彈簧模擬接縫和螺栓、以梁單元模擬襯砌環(huán)的梁一彈簧模型,它是將橫向梁一彈簧模型移植到了隧道結(jié)構(gòu)縱向(見圖3);縱向粱一彈簧模型中每一襯砌環(huán)均由一直線粱模擬,各襯砌環(huán)間的接縫以彈簧模擬,因而在作縱向分析計算時單元較多,它可以模擬襯砌環(huán)和接縫

9、性能有變化的隧道段,但其缺點也是明顯的,即一般適合于線性分析,并且由于以單元作為基礎(chǔ),分析過程為矩陣形式,需要通過數(shù)值方法實現(xiàn),所得結(jié)果需要進行再一次分析才能得到管片、螺栓應(yīng)力和接縫張開度等關(guān)鍵數(shù)據(jù)。另一種模型是以志波由紀(jì)夫及川島一彥2325為代表的等效軸向剛度模型,該方法認(rèn)為隧道在橫向為一均質(zhì)圓環(huán)、在縱向以剛度等效的方法將有環(huán)向接縫非連續(xù)的結(jié)構(gòu)等效為連續(xù)均質(zhì)圓筒。由于是直接從分析襯砌環(huán)向接縫和螺栓的受力變形性能出發(fā)得到等效模型,因此計算結(jié)果可直接給出管片和螺栓應(yīng)力,并且在很多情況下可推導(dǎo)得到顯式理論解,應(yīng)用方便,但該方法也有未考慮預(yù)應(yīng)力、只簡單被認(rèn)為是彈性地基上的直梁等缺點,然而,根據(jù)目前國

10、內(nèi)外的研究現(xiàn)狀來看,軸向等效剛度方法是當(dāng)前隧道結(jié)構(gòu)的縱向理論研究中提出的最好的方法。該法為研究盾構(gòu)隧道縱向問題奠定了堅實的理論基礎(chǔ)。 3盾構(gòu)隧道結(jié)構(gòu)拼裝型式盾構(gòu)隧道結(jié)構(gòu)是由管片在環(huán)向和縱向通過螺栓連接而成的非連續(xù)結(jié)構(gòu)。由于預(yù)制鋼筋混凝土管片經(jīng)濟、耐久及強度高,所以成為目前國內(nèi)外的盾構(gòu)法隧道管片的主要形式。盾構(gòu)隧道襯砌結(jié)構(gòu)拼裝型式有兩種:錯縫拼裝襯砌與通縫拼裝襯砌10111219。這兩種拼裝型式的不同之處在于;錯縫拼裝襯砌由于相鄰環(huán)管片間結(jié)構(gòu)剛度沿環(huán)向分布的不同,雖然受到的初始荷載基本相同,但結(jié)構(gòu)變形卻不同、引起的地層反力不同,地層反力的不同又加劇了結(jié)構(gòu)變形的不同。由于相鄰環(huán)之間存在聯(lián)系,如連接

11、螺栓、環(huán)面凹凸榫槽和環(huán)面間的摩擦又阻礙了結(jié)構(gòu)變形的不同,使結(jié)構(gòu)變形與荷載及地層反力分布的不同限于一定的范圍之內(nèi)。而通縫拼裝襯砌由于相鄰環(huán)管片間結(jié)構(gòu)剛度沿環(huán)向分布相同,受到的初始荷載也基本相同。因此,結(jié)構(gòu)變形基本相同、引起的地層反力也基本相同。雖然,通縫拼裝襯砌每一環(huán)橫向變形也受到相鄰環(huán)的嵌固和約束,但這種約束和影響的效應(yīng)錯縫比通縫更顯著。襯砌環(huán)間的這種相互作用非常復(fù)雜,因此錯縫襯砌內(nèi)力與變形的計算也比較復(fù)雜,其計算模型與計算方法還在深入研究之中。在我國,上海先期施工的盾構(gòu)法隧道基本采用通縫拼裝形式,而上海近期建設(shè)的隧道及廣州和南京地鐵盾構(gòu)法隧道則全部采用錯縫拼裝形式,從而說明錯縫拼裝形式在抵抗

12、縱向變形上優(yōu)于通縫拼裝形式。既然不同的拼裝形式有不同力學(xué)效果,能夠改變襯砌的縱向剛度及控制縱向裂縫和不均勻變形,那么采用更多不同力學(xué)效果的拼裝形式就成為解決當(dāng)前軟土盾構(gòu)隧道結(jié)構(gòu)縱向問題的另一關(guān)鍵問題。4軟土盾構(gòu)隧道結(jié)構(gòu)存在問題從當(dāng)前工程設(shè)計的實際應(yīng)用和理論研究進展分析可得出軟土盾構(gòu)隧道襯砌結(jié)構(gòu)在考慮縱向問題時的不足之處:缺乏與縱向理論要求接近的襯砌形式;現(xiàn)有的縱向理論缺乏與工程實際的結(jié)合;襯砌拼裝形式單一(不能協(xié)調(diào)縱向不均勻變形);襯砌管片材料在同一工程中單一;襯砌管片寬度在同一工程中單一;縱向線形不合理。5軟土盾構(gòu)隧道縱向設(shè)計展望為克服軟土盾構(gòu)隧道現(xiàn)存問題,必須從以下兩方面來解決:(1)從軟

13、土盾構(gòu)隧道襯砌管片拼裝形式、管片材料等方面進行創(chuàng)新改造。以增大軟土盾構(gòu)隧道襯砌結(jié)構(gòu)的縱向剛度的變化,使軟土盾構(gòu)隧道襯砌結(jié)構(gòu)的縱向剛度具有可控性。而不同剛度的多樣的襯砌結(jié)構(gòu)拼裝形式是解決軟土盾構(gòu)隧道縱向問題成為可能。(2)在縱向設(shè)計理論研究及其成果應(yīng)用上應(yīng)有所加強。隧道縱向結(jié)構(gòu)性能的研究和橫向性能研究相比還處在早期發(fā)展階段,其成果尚未應(yīng)用到工程設(shè)計的實踐中。如何將已有的理論研究成果應(yīng)用于工程設(shè)計(即縱向設(shè)計),使工程設(shè)計更加符合客觀現(xiàn)實。這不僅符合當(dāng)前設(shè)計理論發(fā)展的趨勢,更能實現(xiàn)在設(shè)計階段上就開始著手解決軟土盾構(gòu)隧道現(xiàn)存問題(過量的縱向沉降或不均勻沉降,導(dǎo)致隧道滲水、漏泥或結(jié)構(gòu)局部破壞而影響隧道

14、的正常運營),避免軟土盾構(gòu)隧運營后再進行處理的被動狀態(tài),因此,可節(jié)約大量資金。總之,軟土盾構(gòu)隧道結(jié)構(gòu)縱向設(shè)計理論,不僅是軟土盾構(gòu)隧道結(jié)構(gòu)設(shè)計理論發(fā)展的需要,也是社會發(fā)展的需要。它不僅具有理論價值,而且更具重要的經(jīng)濟意義和社會意義。Design of Shield Tunnel in Soft Soil Longitudinal Survey Abstract: Based on soft soil shield tunnel structure design theory, the current situation and have been built there is soft soil

15、 shield tunnel structure analysis of the problems, pointing out that to overcome the soft soil shield tunnel in the structure of vertical settlement of excessive or uneven settlement caused by the tunnel seepage, leakage mud, the impacts of the tunnel structure, partial destruction of the normal use

16、 and durability The key is to start longitudinal study of design theory. Under the guidance of the longitudinal design theory, through the soft soil shield tunnel lining segment assembled form, the segment in innovation and transformation of materials, so that the design of soft soil shield tunnel m

17、ethod is more scientific and rational. Key words: soft soil; shield tunnel; longitudinal design; underground engineering 1 Overview As the world economy, globalization and social progress, people have their own quality of living environment of rising demand, resulting in rapid increase in the level

18、of urbanization, cities have been expanding. Cities become the worlds countries and regions of political, economic and cultural development centers. However, to the sustainable development of urban construction, resource conservation and environmental protection, urban development and utilization of

19、 more and more builders of all can take advantage of the limited living space, especially in urban underground space, in order to build water supply, drainage, energy and transport underground tunnel. However, with the development and utilization of underground space, a growing number of underground

20、 structures due to the use of the process of non-uniform deformation caused the excess of the underground structure itself and the surrounding environment has become even more serious 1 2. For example, in the ground under the effect of hydrodynamic pressure, the Shanghai Jinshan water diversion proj

21、ect in the shield tunnel (see Figure 1), the horizontal layers of soil and water into the tunnels and the resulting vertical settlement and bending, resulting in circumferential seams further open and soil erosion increased, eventually lead to devastating and destructive horizontal vertical deformat

22、ion force status, the maximum relative differential settlement reached 18cm, the largest transverse diameter of more than 10cm 3. Shanghai Metro Line in April 1995 formally completed and put into operation. After long-term deformation monitoring found that the tunnel in the long-term operation of th

23、e settlement and differential settlement quite large, many of the tunnel section of settlement and differential settlement has been developing, and there is no trend of convergence 4. To the end of 2001 the Peoples Square station - the interval between the Xinzha Station tunnel maximum total settlem

24、ent of more than 200mm; Huangpi Station - the Peoples Square Station tunnel differences in the interval between the settlement of nearly 100mm (see Figure 2). Too much has been uneven deformation of the structure of the tunnel, joint water threat. So far, although the segment of the destruction of r

25、are, but on the 1st line has been found between the ballast and tube sheet cracking phenomenon occurring in the Hanzhong Road Station to Station Huangpi of at least five have been found between the overall track bed and segment and the gap between the cracking phenomenon, intermittent totaled 300m.

26、After investigation found that are basically a large part due to uneven settlement of the tunnel caused by 5. In addition, as the vertical deformation caused by uneven deformation of the segment joints increases, on the 1st line of the tunnel ranges in many areas of water seepage and leaking points,

27、 mainly in girth, cap connected to the block of cross-stitch, etc., while the ring seam leakage is the most difficult to deal with. With the development of uneven deformation of the vertical tunnel, tunnel leakage increasing number of cases, and even affect the normal operation of the MTR. The curre

28、nt practice of building a large number of underground tunnels, the shield construction method has become a major urban underground construction method of tunnel construction, particularly in metro tunnels. Shanghais existing subway line and is being built using this method of construction without ex

29、ception. In Shanghai, like with many coastal cities are located in soft soil strata are widely distributed on the shield tunnel structure is the soft soil environment in which a large number of operations leading to soft soil Shield Tunnel excessive vertical settlement or differential settlement, ca

30、using the tunnel water seepage, leakage or structural partial destruction of mud, and sometimes affect the normal operation of the tunnel 20 21. Therefore, the in-depth study of soft soil shield tunnel longitudinal deformation of the tunnel structure and consider the impact of the vertical structure

31、 of vertical deformation of the lining of the design theory to solve the existing problems of soft soil shield tunnel key, in particular the vertical lining structure design methods. Two vertical lining structure design of the status quo At present, the right domestic and international structural de

32、sign of shield tunnel lining used mainly horizontal design. In China, Chinas Mass Transit Railway and the railway tunnel design specification 6 recommended the use of load structure model, without considering the impact of vertical deformation. Shanghai-based foundation design code 1999 version of t

33、he vertical deformation of shield tunnel, which must be considered 7, proposed shield tunnel longitudinal impact of uneven settlement can not be ignored. Especially the shield work well and interval tunnel junction; tunnel lying under the bottom layer of soil characteristics and mutation Branch; Fut

34、uhoudu drastically changed Department, will have a more significant differential settlement. Made in the design should be in accordance with the estimated differential settlement, set an appropriate amount of deformation crack. Specification also referred to in the construction phase and use phase o

35、f the tunnel structure, the horizontal internal force and deformation calculation, when necessary, should take into account the vertical deformation of the tunnel horizontal internal force and deformation effects. At present, the domestic soft soil for the shield tunnel design models used primarily

36、for homogeneous ring and flexible hinge method 13 17 may apply to use elastic equations. The former is mainly used for checking the use of stage design, which is mainly used for checking the construction stages of the design. In other countries, the International Tunneling Association (International

37、TunnelAssociation) was established in 1978, the tunnel structure model of study groups, the collection of all Member States to adopt the underground structure design model. And in 2000 prepared a Shield Tunnel Lining Design Guide 8, for countries to shield the design of the tunnel structure pointed

38、out the basic principles. Structural model which will be divided into four categories: a continuum or continuum model, the role and reaction models, convergence - a constraint model and engineering analogy. This Chinese scholars Liu Hang, Hou Xieyuan 5 classification (experience in analog model; loa

39、d structure model; stratigraphic structure model; convergence limit model) basically the same. At the same time in the shield tunnel design guidelines when necessary, will be proposed in the settlement of the tunnel vertical load categories included in the special load options to be considered. U.S.

40、 Transportation Research Institute at the 2000 annual report 9 mentions that many in the soft soil of the tunnel, pipeline damage or problems that arise due to uneven settlement of the vertical. Up to a situation that is lying under the soil due to its rural character and unevenly distributed along

41、the longitudinal differential settlement resulting from the vertical. Therefore, the U.S. Transportation Research Institute in 2000 to the tunnel longitudinal design concept, and plans to start research work in this area. This shows that in the current design codes are also not related to the conten

42、ts of the vertical design, but the structure of the vertical structure of problem has attracted broad attention and scholars. Therefore, to carry out longitudinal research design is of great practical significance. Reposted elsewhere in the paper for free download As the tunnel vertical issues are t

43、hree-dimensional problem, its complex structure, vertical structure calculation model is not yet ripe. But it has also made some achievements in scientific research. In engineering measurement and laboratory test, based on a number of tunnels have been established model of the vertical structure cal

44、culation. Present the vertical structure of soft soil tunnel theoretical study can be divided into: testing or measurement analysis, numerical analysis and theoretical analysis method. In theory, analytical method, in accordance with the tunnel joints and bolt to simplify the different methods, the

45、Japanese scholars have put forth a theory of vertical structure of the two tunnels, one is based on Chi and Koizumi, Atsushi Murakami 22 as the representative to axial, shear and bending spring simulation joints and bolts, in order to beam element simulation of ring beam lining a spring model, which

46、 is the horizontal beam-spring model of vertical migration to a tunnel structure (see Figure 3); vertical beam-spring model, each lining both Central by a straight line beam simulation, the lining of the joints between the rings to spring simulation, thus making a more longitudinal analysis of the c

47、alculation unit, which can simulate the performance of lining of the Central and joints have changed the tunnel section, but its shortcomings are obvious, which means they are suitable for linear analysis, and due to the unit as a basis for analysis in matrix form, achieved through numerical methods

48、, the results of an analysis of the need to get re-segment, bolts degree of stress and open joints and other key data . Another model is Shiba and Yukio Kawashima, Kazuhiko 23 25 as the representative of the equivalent axial stiffness model, the method considers that the tunnel in the horizontal for

49、 a homogeneous ring, in the longitudinal stiffness of the equivalent method in order to circumferential seams are non-continuous structure is equivalent to a continuous homogeneous cylinder. Because it is directly from the analysis of circumferential lining of joints and bolts of force-deformation p

50、roperties of the starting model to be equivalent, so the calculation results can be directly given segment and bolt stress, and in many cases can be derived by an explicit theoretical solution, application convenient, but the method has not taken into account pre-stressed, and simply be considered s

51、traight beam on elastic foundation and other shortcomings, however, according to the current situation of the study at home and abroad, the axial equivalent stiffness method is the current theory of the tunnel structure of the longitudinal Research presented in the best way. The method to study the

52、issue of Shield Tunnel longitudinal laid a solid theoretical basis. 3 shield tunnel structure of assembled type Shield tunnel structure is a segment in the circumferential and longitudinal screw connections made through a non-continuous structure. As the pre-cast reinforced concrete segment economy,

53、 durability and high strength, so be at home and abroad of the shield tunnel segment of the main form. Shield tunnel lining structure, assembly, there are two types: the wrong lining of joints assembled themselves and the assembled seam lining 10 11 12 19. These two different types of assembly is th

54、at; wrong lining of joints assembled adjacent ring segment due to structural stiffness between the different distribution along the ring, although the initial load are basically the same, but the structural deformation is different strata caused by anti - force is different from the different strata

55、 reaction exacerbated by structural deformation of the difference. Because there is a link between adjacent rings, such as connecting bolts, torus bump Mortise and torus has hindered friction between the different structural deformation, so that the structure deformation and load and stratigraphic d

56、istribution of the different reactions within the scope be limited to a certain . Tong assembled lining the joints due to the adjacent ring segment between the structural rigidity along the circumferential distribution of the same, subject to the initial load are basically the same. Therefore, the s

57、tructural deformation is basically the same, causing the formation reaction force is also basically the same. Although the assembled lining seam pass lateral deformation of each ring has also been mounted adjacent to Central and constraints, but the effects of constraints and the impact of the wrong

58、 seam sew more pronounced than the pass. This interaction between the lining ring is very complex, sewing lining of the wrong calculation of internal forces and deformation is also more complicated, the calculation model and calculation method are also in-depth studies. In China, Shanghai in advance of construction of the shield tunnel pass the basic use of sewing assembled form, the recent construction of the tunnel in Shanghai and Guangzhou, and Nanjing subway shield t