外文資料翻譯---柔弱巖石上短距離隧道的動(dòng)態(tài)施工力學(xué)的研究

1、<p>　　畢業(yè)設(shè)計(jì)外文資料翻譯</p><p>　　題 目 柔弱巖石上短距離隧道 </p><p>　　的動(dòng)態(tài)施工力學(xué)的研究 </p><p>　　學(xué) 院 土木建筑學(xué)院 </p><p>　　專 業(yè) 土木工程 </p>&

2、lt;p>　　班 級 土木 </p><p>　　學(xué) 生 </p><p>　　二〇一 一 年 三 月 四 日</p><p>　　Modern Applied Science Vol. 4, No. 6; June 2010</p><p>　　柔

3、弱巖石上短距離隧道的動(dòng)態(tài)施工力學(xué)的研究</p><p><b>　　吳恒斌(通訊作者)</b></p><p>　　重慶長江三峽大學(xué)土木工程系</p><p>　　中國重慶萬州市二段沙龍路780號(hào)</p><p>　　電子郵件:hbw8456@163.com</p><p><b>　　

4、賀云翔</b></p><p>　　重慶長江三峽大學(xué)土木工程系</p><p>　　中國重慶萬州市二段沙龍路780號(hào)</p><p><b>　　郭良松</b></p><p>　　聊城建宇工程有限公司</p><p>　　中國聊城252000</p><p>

5、<b>　　摘要</b></p><p>　　基于建設(shè)理論的新奧地利方法((NAM)),依賴在柔弱巖石的短距離隧道工程,通過構(gòu)建數(shù)學(xué)模型并進(jìn)行了三維彈塑性有限元法的建構(gòu)過程中,雙邊墻的施工方法。分析隧道周圍一些測量點(diǎn)位移的變化和隧道開挖和洞室群圍巖的穩(wěn)定性,通過分析地表塌陷、承擔(dān)的力量支護(hù)結(jié)構(gòu)與塑性區(qū)。結(jié)果表明,上述構(gòu)造法是合理的在以后的隧道開挖，地表沉陷，隧道變形與早期隧道開挖的影響比較明

6、顯。</p><p>　　關(guān)鍵詞:柔弱的巖石、小距離隧道、動(dòng)態(tài)建筑機(jī)械、數(shù)值模擬</p><p><b>　　1介紹</b></p><p>　　過程的開挖與支護(hù)隧道是一項(xiàng)復(fù)雜的機(jī)械加工過程，施工過程之間的差別，開挖順序，支持的時(shí)間大為影響工程結(jié)構(gòu)系統(tǒng)(SHE et al., 2006).的力學(xué)效應(yīng)由于周圍巖石條件的復(fù)雜性普通的類似項(xiàng)目在柔弱巖

7、石特別是小距離隧道工程的復(fù)雜連接中是不夠的，因此,根據(jù)在施工過程中各負(fù)荷情況，在不同的圍巖中有必要進(jìn)行機(jī)械模擬和分析在柔弱巖石隧道襯砌方面的研究，SUN et al. (1994)考慮了時(shí)空效應(yīng)隧道挖掘表面建立三維數(shù)模型。CHENG et al. (1997) 分析了力學(xué)機(jī)制和FLAC隧道襯里復(fù)雜的承載能力，得到一些有用的結(jié)論。JIN et al. (1996) 應(yīng)用非線性粘彈性理論進(jìn)行了三維有限元模擬圓隧道開挖過程。Karakus(2

8、007)闡述了由平面應(yīng)變分析造成的三個(gè)尺寸挖掘影響。因?yàn)闀r(shí)空效應(yīng)還不能全部體現(xiàn),許多研究人員進(jìn)行了三維彈塑性有限元法和隧道開挖的彈塑性分析(AN, 1994, XIAO, 2000 & ZHU et al. 1996)。在小距離隧道方面的研究LIU et al. (2000)在中國第一個(gè)超級短距離隧道進(jìn)行的測試中距離隧道在中國。WAN et al. (200</p><p>　　距離8車道公路隧道的設(shè)計(jì)方

9、案。大多數(shù)上述研究的目的分別是柔弱巖石隧道的建筑特征和小距離隧道建設(shè)方案的比較和選擇由于很少做結(jié)合兩方面的討論，因此，有必要研究小距離柔弱巖石動(dòng)態(tài)施工特點(diǎn)。</p><p><b>　　2工程概況</b></p><p><b>　　2.1工程地質(zhì)</b></p><p>　　地質(zhì)調(diào)查顯示,底部隧道主要打通的是下面的基礎(chǔ)，

10、主要是泥巖，砂巖。撞擊地層的方向交叉降至85°。隧道、地層傾角約有9°,結(jié)合層巖石很普通，巖石的等級是五級。地下水很匱乏，隧道中水的主要形式是潮濕或滴下來。鋼筋混凝土的極限抗壓強(qiáng)度= 4.59Mpa，完整性因素KV=0.65,K1 = 0.2,K2 = 0.3,K3 = 0,[工程量清單計(jì)價(jià)]= 219。砂巖鋼筋混凝土的極限抗壓強(qiáng)度=2549Mpa,完整因素KV=0.64,K1= 0.5,K2 = 0.2,K3 =

11、0,[工程量清單計(jì)價(jià)]= 319。地質(zhì)構(gòu)造的表面非常發(fā)達(dá)，巖體極其支離破碎,而且塊強(qiáng)度不夠強(qiáng)。所以它屬于典型的類柔弱的巖石。</p><p>　　2.2工程施工方法。</p><p>　　雙墻指導(dǎo)施工方法中的配角,以先進(jìn)的小管為了減少隧道施工對高速公路經(jīng)營管理的影響，確保隧道建設(shè)的安全雙邊墻施工方法以先進(jìn)的小管作為支撐角色引導(dǎo)。先進(jìn)小管的外半徑是Φ42mm,長度是四十厘米。在施工過程中,開

12、挖的長度是受到嚴(yán)格控制的，主要支撐每隔四米設(shè)置一個(gè)。30厘米厚的封閉鋼筋混凝土環(huán)被襄鑄在第二內(nèi)襯和主要支撐之間。螺栓的形式是空心注漿和quincunx布局、直徑和長度是作為軌道后,4.5米、垂直和周向所在分別是200厘米和80厘米第二內(nèi)襯和主要支撐被澆鑄成28厘米厚C20模型和60厘米厚C25厚鋼筋混凝土模型</p><p><b>　　3數(shù)值模型</b></p><p&

13、gt;　　隧道長度是選為仿真模型,該模型被選為20米長，該模型有21850個(gè)小構(gòu)件其中螺栓有3850構(gòu)件(圖1)。隧道圍巖被認(rèn)為是彈塑性材料。因?yàn)橹谓Y(jié)構(gòu)的力學(xué)性能優(yōu)于圍巖,所以它可以被看作是彈性材料。鋼拱的影響在架子上和先進(jìn)的小管噴射混凝土可以模擬使用等效的方法。Tab.1是基本力學(xué)參數(shù)的物質(zhì)。為確保計(jì)算的準(zhǔn)確性該模型維度可以設(shè)為:左和右都長50米垂直于地球表面下為50米。</p><p><b>　

14、　4進(jìn)行結(jié)果分析</b></p><p>　　4.1分析地表沉陷,</p><p>　　地面沉降應(yīng)嚴(yán)格控制,以確保隧道施工中高速公路運(yùn)營管理的安全隧道施工。從圖2,圖像的地表沉陷隧道開挖完成后,它可以看出地表沉陷對稱分布近似在雙線隧道、展示W(wǎng)的形狀。早期隧道拱頂端地面沉降規(guī)模最大，沉降值為5.31mm，這是由于早期隧道開挖完成以后，后期隧道建設(shè)造成的擾動(dòng)，這和現(xiàn)場監(jiān)測的信息和數(shù)

15、據(jù)規(guī)</p><p>　　則是一致的。后期隧道拱頂端地面沉降量是5.31mm。在隧道中軸線附近的地表沉降</p><p>　　小于兩個(gè)隧道拱頂所在的地表沉降，沉降值只有2.87mm?？梢詮膱D二中得出的結(jié)論是隧道開挖的影響對地表沉陷趨于穩(wěn)定的距離范圍是中軸線直徑的3.5倍,也揭示了該仿真模型的選擇范圍是沒有錯(cuò)誤的</p><p><b>　　4.2巷道變形分

16、析</b></p><p>　　如圖3所示,后期隧道拱頂端的垂直地表沉降是7.20mm,最大的垂直地表沉降值出現(xiàn)在早期隧道拱頂端。因?yàn)橹蟮乃淼朗┕ば?是7.33mm。與一般的大垮較淺深度的隧道地表沉降的現(xiàn)場測量值相比，頂部處理的沉降值略小。可以假定,先進(jìn)的小管在加固巖石上發(fā)揮了很大作用，逆變值相對較大，早期的隧道和后期的隧道分別是9.87mm 9.85mm。分析結(jié)果表明,隧道圍巖的垂直缺陷值滿足施工

17、的需要、初始參數(shù)設(shè)定隧道結(jié)構(gòu)是合理的。</p><p>　　4.3支撐承載力的分析</p><p>　　如圖4所示,出現(xiàn)在拱腳的最大受力值是7.31Mpa.。在施工過程中應(yīng)該加強(qiáng)現(xiàn)場監(jiān)測的力度。從圖五中以發(fā)現(xiàn)在拱頂和拱腳位置的螺栓的軸向力更大。最大值是42.56kN，滿足抗拉強(qiáng)度要求。螺栓軸向力最主要的分布形式是“凸肚”式。符合螺栓軸向力在柔弱巖石上的分布格局。處在拱腳位置的少量螺栓時(shí)處于

18、壓縮狀態(tài)的。可能由于主要支撐的剛度太大，結(jié)果是減少了拱腳的變形和反演脹的現(xiàn)象。從圖六中可以看出第二內(nèi)襯的應(yīng)力規(guī)律和主要支撐是相似的，邊墻的壓力要大于其他部位最大應(yīng)力值是0.2Mpa滿足在中國要求的標(biāo)準(zhǔn)</p><p><b>　　4.4塑性區(qū)分析</b></p><p>　　從圖7,便會(huì)發(fā)現(xiàn),塑性區(qū)主要分布在拱頂、拱門、拱門腳的位置，這也許是由于由雙邊墻施工方法造成的

19、過多的應(yīng)力進(jìn)入了側(cè)墻 。先進(jìn)的小管的支持、初期支護(hù),其次內(nèi)襯可以預(yù)防塑性區(qū)進(jìn)一步擴(kuò)張,塑性區(qū)深度,不會(huì)超過一半的隧道寬度,而在允許范圍內(nèi)。所以隧道圍巖塑性區(qū)的發(fā)隧洞的穩(wěn)定性隧道仍然情況穩(wěn)定。</p><p><b>　　5結(jié)論</b></p><p>　　隧道地表沉陷的分布在中心軸線基礎(chǔ)上,顯示W(wǎng)型,由于解決方案主要集中在3.5倍中心軸線的直徑范圍內(nèi)，先進(jìn)小管的支持能

20、夠加固圍巖有效防止兩個(gè)隧道之間塑性區(qū)的擴(kuò)張。從圍巖結(jié)構(gòu)的變形結(jié)果可以看到后期隧道開挖地表沉陷與隧道變形對早期的隧道的影響大于早期隧道開挖對后期隧道的影響。對上述結(jié)果進(jìn)行分析地面沉降、隧道周邊的垂直位移，支撐的承載力和塑性區(qū)雙邊墻建設(shè)方案是合理的。</p><p><b>　　參考文獻(xiàn)</b></p><p>　　【中國巖石力學(xué)與工程】（3，623-629）三維彈塑性數(shù)

21、值模擬軟圍巖位移建設(shè)的進(jìn)程。佘健，何川（2006年）。</p><p>　　【巖土力學(xué)】（4，20-33。）力學(xué)模擬及軟弱巖石中的行為分析，興建一條隧道開放。孫軍，朱合華（1994年）。</p><p>　　【巖土力學(xué)】（4，327-336）數(shù)值分析大型復(fù)雜的非線性變形機(jī)制及隧道襯砌。鄭華，孫軍（1997年）。</p><p>　　【巖石和土壤力學(xué)】（3，193-

22、200）模擬三維隧道挖掘。靳鳳年、錢七虎（1996年）。?！舅淼琅c地下空間技術(shù)】（22，47-56）評價(jià)隧道的二維平面應(yīng)變有限元分析的影響及三維方法核算。M.Karakus（2007年）。【中國民建工程】（5，87-91）三維有限元的軟土蠕變對隧道的影響。安官峰(2001年）?！局袊鴰r土工程學(xué)報(bào)】（4，421-425)三維數(shù)值模型的地下洞室施工過程。肖明（2000年）。</p><p>　　【施工力學(xué)】（北京

23、科學(xué)出版社）周邊復(fù)雜條件下圍巖穩(wěn)定性和巖石動(dòng)態(tài)。朱煒沉，何滿潮（1996年）</p><p>　　【巖土力學(xué)】（5，590-594）實(shí)驗(yàn)研究機(jī)械特性和小間距隧道。劉顏青，韓世航，盧汝綏，馬榮田（2000年）?！靖咚俟贰浚?，55-58）討論環(huán)境對小間距研究長隧道的影響。萬明富（2000年）?！舅淼腊踩こ屉s志】（2，63-68）開挖小距離隧道的方法分析。金曉廣，劉煒，秦峰，汪劍華（2004年）。</p&

24、gt;<p>　　【中國巖石工程力學(xué)】（3，572-577）對軟巖施工特性和動(dòng)態(tài)行為的研究。嚴(yán)琦祥，何川，姚勇（2006年）。。</p><p>　　【高速公路】（12，217）大跨公路隧道結(jié)構(gòu)設(shè)計(jì)與分析。劉紅州，陳三佳（2006年）</p><p>　　圖1 有限元分析模型</p><p>　　圖2 地表沉陷圖表

25、 圖3 圍巖的垂直位移（mm）</p><p>　　圖4 主要支撐的等量壓力 圖5 螺栓的軸力圖</p><p>　　圖6 次連接的等量應(yīng)力 圖7 圍巖的塑性區(qū) </p><p>　　Study on Dynamic Construction Mechanics

26、 of Small-Distance Tunnel</p><p>　　in Soft and Weak Rocks</p><p>　　Hengbin Wu (Corresponding author)</p><p>　　Department of Civil Engineering, Chongqing Three Gorge University</p

27、><p>　　780 Erduan Shalong Road, Wanzhou District, Chongqing 404000, China</p><p>　　E-mail: hbw8456@163.com</p><p>　　Yunxiang He</p><p>　　Department of Civil Engineering, C

28、hongqing Three Gorge University</p><p>　　780 Erduan Shalong Road, Wanzhou District, Chongqing 404000, China</p><p>　　Guoliang Song</p><p>　　Liaocheng Jianyu Construction Engineering

29、 Co.,Ltd</p><p>　　Liaocheng 252000, China</p><p><b>　　Abstract</b></p><p>　　Based on the construction theory of New Austria Method(NAM), relyed on a tunnel project of sm

30、all distance in</p><p>　　soft and weak rocks, this paper builds the numerical model and simulates 3D finite element method elastoplastic</p><p>　　of the construction process by the construction

31、method of double-sidewalls. The displacement changes of some</p><p>　　points around the tunnel are analysised with the tunnel’s excavation. The safety of the tunnel structure and</p><p>　　stabil

32、ity of surrounding rock are estimated by analyzing the surface subsidence, forces undertaken by the</p><p>　　supporting structures and plastic zone. The results show that the method of construction mentioned

33、 above is</p><p>　　reasonable, the influence of the later tunnel excavation on the surface subsidence and tunnel deformations of the</p><p>　　earlier tunnel excavation is relatively obvious.<

34、/p><p>　　Keywords: Soft and weak rocks, Small distance tunnel, Dynamic construction mechanics, Numerical simulation</p><p>　　1. Introduction</p><p>　　The excavation and supporting proc

35、ess of tunnel is a complicated mechanical process, the differences of</p><p>　　construction process, excavation sequence and supporting time greatly influence on the mechanics effects of</p><p>

36、　　engineering structure systematic(SHE et al., 2006). Because of the complexity of the condition of surrounding</p><p>　　rock, the ordinary analogy of projects is not enough in the complex lining in soft and

37、 weak rocks especially in</p><p>　　the tunnel engineering with small distance, so it’s necessary to conduct the mechanical simulating and analyzing</p><p>　　in different surrounding rock charact

38、ers according to the different forcing stages in each load case during</p><p>　　construction processes.</p><p>　　In the aspect of the research on the tunnel lining in soft and weak rocks, SUN et

39、 al. (1994) builded the three</p><p>　　dimension model considering the time-space effect of tunnel excavating surface. CHENG et al. (1997) analyzed</p><p>　　the mechanical mechanism and carrying

40、 capacity of complex lining for tunnels with FLAC, and got some useful</p><p>　　conclusions. JIN et al. (1996) conducted three dimension FEM (finite element method) numerical simulation to</p><p&g

41、t;　　the excavation processes of circle tunnel using the nonlinear viscoelastic theory. Karakus(2007)elaborated three</p><p>　　dimension excavating effect caused by plane strain analyses. Because the time-spa

42、ce effect could not be fully</p><p>　　reflected, many researchers conducted three dimension FEM elastoplastic and visco-elastoplastic analyses to</p><p>　　tunnel excavation(AN, 1994, XIAO, 2000

43、& ZHU et al., 1996).In the aspect of the research in the tunnel of</p><p>　　small distance, LIU et al. (2000) carried out the tests on Zhaobaoshan tunnel, which is the first super small</p><p&

44、gt;　　distance tunnel in China. WAN et al. (2000) made specifically the concept of small distance tunnel. JIN et al.</p><p>　　(2004) discussed the adaptability of the construction methods through the numerica

45、l simulating. YAN et al.</p><p>　　(2006) analyzed the mechanical characteristic and deformation rules of the supports in different construction</p><p>　　methods. LIU et al. (2006) introduced the

46、 design scheme of highway tunnel of small distance with 8 lanes. Most</p><p>　　of studies mentioned above were aimed separately at construction characters of the tunnel in soft and weak rocks</p><

47、p><b>　　117</b></p><p>　　Modern Applied Science www.ccsenet.org/mas</p><p>　　and the comparison and selection of the construction schemes of small distance tunnel. The discussion&l

48、t;/p><p>　　combining the two aspects is less made, so it’s necessary to study the dynamic construction mechinics</p><p>　　characteristic of small distance tunnel in soft and weak rocks.</p>

49、<p>　　2. Engineering General Situation</p><p>　　2.1 Engineering Geology</p><p>　　The geological survey shows that the bottom, the tunnel mostly get through, is the Jurassic upper Shaximiao,

50、 and</p><p>　　the underlying bedrock is the interbedded of mudstone and sandstone. The strike direction of the strata intersect</p><p>　　the tunnel axis to 85°, the strata dip angle is abou

51、t 9°, the combination between the layers of rock is general, and</p><p>　　the level of rock is grade V. The groundwater is poor, and the main form of the water in tunnel is damp or</p><p>　

52、　dripping. The saturated uniaxial compressive strength of mudstone Rc=4.59Mpa, Integrity factor Kv=0.65,</p><p>　　K1=0.2, K2=0.3, K3=0, [BQ]=219. The saturated uniaxial compressive strength of Sandstone Rc=2

53、5.49Mpa,</p><p>　　integrity factor Kv=0.64, K1=0.5, K2=0.2, K3=0, [BQ]=319. The surface of geological structure is very</p><p>　　developed, the rock body is extremely fragmented, and the block s

54、trength is not strong. So it belongs to the</p><p>　　typical category of the soft and weak rocks.</p><p>　　2.2 Engineering Construction Method</p><p>　　The double side-walls constru

55、ction method is guided under the supporting role with advanced small pipe, in</p><p>　　order to reduce the influence of tunnel construction on the highway operations, ensure the safety of tunnel</p>&

56、lt;p>　　construction. The outside radius of advanced small pipe is Φ42mm, the length is 3.5m and the circumferential</p><p>　　spacing is 40cm. In the construction process, the excavation length is controll

57、ed strictly, the primary support is</p><p>　　constructed every 4m, and the 30cm thick closed loop of steel concrete is molded between the secondly lining</p><p>　　and primary support. The bolts

58、are the forms of hollow grouting and quincunx layout, the diameter and length</p><p>　　are setted as 25mm and 4.5m, the vertical and circumferential spacing are located 200cm and 80cm apart. The</p>&

59、lt;p>　　primary support and secondly lining are forms of the 28cm thick C20 shotcrete and 60cm thick C25 model</p><p>　　reinforced concrete.</p><p>　　3. NumericalModel</p><p>　　Th

60、e tunnel length in simulating model is selected as 20m, and the model has 21850 elements, in which bolts</p><p>　　have 3850 elements(Fig.1). The tunnel surrounding rock is considered to be elastoplastic mate

61、rial. Because the</p><p>　　mechanics characteristic of the support structure is better than the surrounding rock, so it could be regarded as</p><p>　　elastic material. The effect of steel arch s

62、helf in shotcrete and advanced small pipe could be simulated using</p><p>　　equivalent method. Tab.1 is the basic mechanics parameter of the material. In order to ensure the veracity of</p><p>　

63、　calculation, the model dimension can be set as : left and right are all 50m, vertical to earth surface, down is 50m.</p><p>　　4 Results Analysis</p><p>　　4.1 Surface Subsidence Analysis</p&g

64、t;<p>　　The surface subsidence should be strictly controlled, in order to ensure the safety of highway operations in the</p><p>　　tunnel construction. From Fig.2, the graph of the surface subsidence a

65、fter completion of the tunnel excavation, it</p><p>　　can be seen that the surface subsidence is approximate symmetrical distribution on the two-lane tunnel, showing</p><p>　　W shape. the surfac

66、e subsidence in the top of the earlier tunnel vault is largest, the value is 5.31mm, which is due</p><p>　　to the construction disturbance caused by the later tunnel after completion of the earlier tunnel ex

67、cavation. This</p><p>　　is consistent with the information and data rules of on-site monitoring. The surface subsidence in the top of the</p><p>　　later tunnel vault is 5.31mm, the surface subsi

68、dence near the central axis line are smaller than the top of the two</p><p>　　tunnel vaults, the value is only 2.87mm. Generally speaking, the surface subsidence can guarantee normal</p><p>　　co

69、nstruction under the safety operation of highway. The conclusion, which could also be seen from Fig.2, is that</p><p>　　the impact of the tunnel excavation on surface subsidence tends to be stable in the ran

70、ge of the distances of 3.5</p><p>　　times the diameter to the central axis, which also indicates the selection range of this simulation model is within</p><p>　　the error.</p><p>　　

71、4.2 Tunnel Deformation Analysis</p><p>　　As can be seen from Fig.3, the vertical subsidence of the later tunnel vault is 7.20mm, and the largest value of</p><p>　　the vertical subsidence, which

72、appears in the earlier tunnel vault because of the construction effect of the later</p><p>　　tunnel, is 7.33mm. The value of crown settlement is slightly small compared with the on-site monitoring value of&l

73、t;/p><p>　　the tunnels with general shallow-depth and large-span. It can be assumed that, the advanced small pipe has</p><p>　　played effectively a role of reinforcing rock. The invert heaving valu

74、e is relatively large, the earlier tunnel and</p><p>　　later tunnel are 9.87mm, 9.85mm. The analysis indicates that the vertical deformation of the tunnel surrounding</p><p><b>　　118</b

75、></p><p>　　Modern Applied Science Vol. 4, No. 6; June 2010</p><p>　　rock meets the construction requirement, the initial parameters set of the tunnel structures are reasonable.</p><

76、;p>　　4.3 Analysis of Forces Undertaken by Supports</p><p>　　As can be seen from Fig.4, the largest value which appears in the arch foot is 7.31Mpa. The on-site monitoring in</p><p>　　the arch

77、 foot should be strengthened in the construction process. From Fig.5, it can be found that, the axial force</p><p>　　of bolts is larger in the position of the vault and hance, the largest value is 42.56kN, w

78、hich meets the requirement</p><p>　　of the tensile strength. The most distribution of the bolts axial force is the form of “convex belly”, which is</p><p>　　consistent with the distribution patt

79、ern of the bolt axial force in soft and weak rocks. A small amount of bolts in</p><p>　　arch foot position are compression state, which maybe due to the stiffness of the primary support is too large,</p&g

80、t;<p>　　resulting in less deformation of arch foot and the phenomenon of invert heaving. As can be seen from Fig.6, the</p><p>　　stress law of the secondly lining is similar with primary support. The

81、side-wall stress is larger than the others, the</p><p>　　largest value is 0.2Mpa, which meets the requirement criterion in China.</p><p>　　4.4 Plastic Zone Analysis</p><p>　　From Fi

82、g.7, it can be seen that, the plastic zone is mainly distributed in the position of the vault, arch and arch</p><p>　　foot, which is probably due to the side-walls undertaken excessive forces caused by doubl

83、e-sidewalls</p><p>　　construction method. The supports of advanced small pipe, primary support and secondly lining can prevent</p><p>　　effectively the further expansion of the plastic zone, the

84、 depth of plastic zone does not exceed the half of the</p><p>　　tunnel width, which is within the allowable range. Therefore the development of plastic zone of the tunnel does</p><p>　　not affec

85、t significantly the stability of the tunnel, and the tunnel is still in stable condition.</p><p>　　5. Conclusions</p><p>　　The distribution of the tunnel surface subsidence is on the central axi

86、s basis, showing W shape, and the</p><p>　　settlement mainly concentrated in the range of the distance of 3.5 times the diameter to the central axis. The</p><p>　　support of advanced small pipe

87、can reinforce the surrounding rock, and prevent effectively the expansion of the</p><p>　　plastic zone between the two tunnels. From the deformation results of the surrounding rock, it can seen that, the<

88、/p><p>　　influence of the later tunnel excavation on the surface subsidence and tunnel deformations of the earlier tunnel</p><p>　　excavation is larger than the earlier tunnel impacts on the later

89、tunnel. From the results analysis mentioned above</p><p>　　of the surface subsidence, vertical displacement of the tunnel surrounding, undertaken forces of the supports and</p><p>　　the plastic

90、zone, the construction schemes of double- sidewalls is reasonable.</p><p>　　References</p><p>　　SHE Jian, & HE Chuan. (2006). 3D elastoplastic numerical simulation of surrounding rock displa

91、cement in soft</p><p>　　surrounding rock sectionduring construction process. Chinese Journal of Rock Mechanics and Engineering, 3,</p><p><b>　　623-629.</b></p><p>　　SUN

92、Jun, & ZHU He-hua. (1994). Mechanical simulation and analysis of behavior of soft and weak rocks in the</p><p>　　construction of a tunnel opening. Rock and Soil Mechanics, 4, 20-33.</p><p>　

93、　Cheng Hua, & Sun Jun. (1997). Numerical analysis of large nonlinear deformation mechanism for complex</p><p>　　tunnel lining in incompentent countryrock. Rock and Soil Mechanics, 4, 327-336.</p>

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95、ethods accounting for 3D tunneling effects in 2D plane strain FE analysis.</p><p>　　Tunnelling and Underground Space Technology, 22, 47-56.</p><p>　　AN Guan-feng. (2001). 3D-FEM for the effect o

96、f soft-soil creep on tunnel. Chinese Journal of Civel Engineering,</p><p><b>　　5, 87-91.</b></p><p>　　XIAO Ming. (2000). Three-dimensional numerical model of construction process for

97、 underground opening.</p><p>　　Chinese Journal of Geotechnical Engineering, 4, 421-425.</p><p>　　ZHU Wei-shen, & HE Man-chao. (1996). Surrounding rock stability under complicated condition a

98、nd rock</p><p>　　dynamic construction mechanics. Beijing: Science Press.</p><p>　　LIU Yan-qing, HAN Shi-hang, LU Ru-sui, & MA Rong-tian. (2000). Experimental study on mechanical</p>&

99、lt;p>　　characteristics of twin tunnels with small spacing. Rock and Soil Mechanics, 5, 590-594.</p><p>　　WAN Ming-fu. (2000). Discussion of the tunnel surrounding rock spacing and study on the tunnel with

100、 small</p><p>　　distance, highway, 7, 55-58.</p><p>　　JIN Xiao-guang, LIU Wei, QIN Feng, & WANG Jian-hua. (2004). Excavation method analysis of little distance</p><p><b>　

101、　119</b></p><p>　　E /MPa © 3 /KN/m c /MPa ? /° ?</p><p>　　Surrrounding Rockk 410 21 0.1040 29 0.38</p><p>　　Reiinforced Rockk 460 21 0.1290 32 0.35</p><p&

102、gt;　　Priimary Support 28000 23 — — —</p><p>　　Senncondly Liningg 31000 25 — — —</p><p><b>　　g, mic</b></p><p><b>　　sh</b></p><p>　　Modern Applii

103、ed Science www.cccsenet.org/maas</p><p>　　tunnel in freewway. Jouranal of Eailway Enngineering Socciety, 2, 63-68.</p><p>　　YAN Qi-xiang HE Chuan, & YAO Yong. (2006). Study on Constructtion

104、characteriistic and dynam behavior of</p><p>　　soft rock tunnnel. Chinese Joournal of Rock Mechanics annd Engineeringg, 3, 572-577.</p><p>　　LIU Hong-zhhou, & CHEN Jia. (2006). Structure des

105、ign and analysis of hallow-embeddding long-spaan</p><p>　　neighbourhood highway tunnnel, highway, 12, 217-222.</p><p>　　Figure 1. The Finite Element Analyssis Model</p><p>　　Table 1

106、. Baasic mechanicaal parameters oof surroundingg rock and tunnnel structures</p><p>　　Figure 2. The Graph of Surface Subbsidence</p><p><b>　　120</b></p><p><b>　　th

107、</b></p><p><b>　　th</b></p><p>　　Moderrn Applied Sciience Vool. 4, No. 6; Junne 2010</p><p>　　Figure 3. Thhe Vertical Dissplacement of tthe Surroundinng Rock(mm)&l