本文選題：淺埋軟巖　切入點：現(xiàn)場試驗　出處：《北京交通大學》2014年碩士論文　論文類型：學位論文

【摘要】：大規(guī)模的高速鐵路建設(shè)中,不可避免的遇到各種復(fù)雜地質(zhì)狀況的隧道,淺埋軟巖隧道就是其中一種。本文依托貴廣高速鐵路賀街隧道,進行了大量的現(xiàn)場試驗,對采用6部CRD、二臺階、三臺階臨時仰拱法施工的淺埋軟巖隧道的地表沉降、地層分層沉降、初期支護的內(nèi)力進行了現(xiàn)場監(jiān)測,獲取了大量實測數(shù)據(jù),并結(jié)合FLAC3D取得了以下研究成果： (1)實測數(shù)據(jù)結(jié)果表明淺埋軟巖隧道地表沉降經(jīng)歷前期變形階段-加速變形階段-趨于穩(wěn)定階段的歷時過程,超前沉降比例和超前影響距離主要受到開挖跨度的影響；初期支護的及時閉合對軟弱圍巖變形的控制具有至關(guān)重要的作用；地層深部相對地表的沉降,經(jīng)歷前期變形階段-加速變形階段-緩慢抬升階段-趨于穩(wěn)定階段的歷時過程,其中緩慢“抬升”即意味著地層變形得到初步控制；文中還對比分析了不同超前加固措施對圍巖變形的影響,結(jié)果表明地表旋噴樁加固后地表沉降減小55%,抗滑樁對控制偏壓具有非常明顯的作用,抗滑樁加固后地表沉降槽曲線較為對稱。 (2)通過現(xiàn)場監(jiān)測支護應(yīng)力、應(yīng)變,認為淺埋軟巖隧道上覆地層自承載能力微弱,圍巖壓力表現(xiàn)為松散土壓力,開挖初期初支-圍巖接觸壓力增長迅速,部分斷面在前期施工中壓力就已經(jīng)基本達到上覆全土柱自重；另外,下層圍巖的開挖會引發(fā)“掉拱”,從而導致初支內(nèi)力突變,對初支混凝土的破壞性較強。 (3)結(jié)合實測圍巖變形與初支-圍巖接觸壓力,得出實測拱頂沉降與接觸壓力之間的關(guān)系曲線,分析了采用不同施工方法時的圍巖變形控制的合理范圍。 (4)在變位分配原理的基礎(chǔ)上,用FLAC3D模擬獲得不同施工方法各施工步序的圍巖變形的比例及控制值,結(jié)合實測資料,實現(xiàn)了對施工過程中拱頂沉降的控制,保證了二次襯砌的厚度,并對采用不同施工方法的不同施工段進行了拱頂預(yù)留量的優(yōu)化分析,降低了施工成本。
[Abstract]:In the large-scale construction of high-speed railway, it is inevitable to encounter various kinds of tunnels with complicated geological conditions, among which the shallow soft rock tunnel is one of them. In this paper, a large number of field tests have been carried out based on the Hejie Tunnel of the Gui-Guang High Speed Railway. In this paper, the ground subsidence, stratified settlement and initial supporting internal force of shallow soft rock tunnel constructed by 6 CRD, two steps, three steps temporary invert method are monitored on the spot, and a large number of measured data are obtained. Combined with FLAC3D, the following research results have been obtained:. 1) the measured data show that the surface settlement of shallow soft rock tunnel goes through the process of early deformation, acceleration deformation and stabilization, and the advance settlement ratio and the advance influence distance are mainly affected by the excavation span. The timely closure of initial support plays an important role in controlling the deformation of soft surrounding rock, and the settlement of deep strata relative to the surface of the earth goes through the process of early deformation stage, acceleration deformation stage, slow uplift stage and stabilization stage. The slow "uplift" means that the deformation of the stratum is controlled preliminarily, and the influence of different advanced reinforcement measures on the deformation of surrounding rock is also compared and analyzed in this paper. The results show that the surface settlement is reduced by 55%, the anti-slide pile plays an obvious role in controlling the bias, and the surface settlement trough curve is more symmetrical after the reinforcement of the anti-slide pile. (2) through field monitoring of support stress and strain, it is considered that the self-bearing capacity of overlying stratum in shallow soft rock tunnel is weak, the surrounding rock pressure is expressed as loose soil pressure, and the initial branch and surrounding rock contact pressure increase rapidly in the early stage of excavation. In the early stage of construction, the pressure of some sections has basically reached the deadweight of the overburden whole earth column, in addition, the excavation of the surrounding rock of the lower layer will cause "arch drop", which will lead to the sudden change of the internal force of the initial support, which will be more destructive to the concrete of the initial support. 3) based on the measured deformation of surrounding rock and the contact pressure between initial branch and surrounding rock, the relation curve between measured settlement of arch roof and contact pressure is obtained, and the reasonable range of deformation control of surrounding rock under different construction methods is analyzed. 4) on the basis of the principle of displacement distribution, the proportion and control value of surrounding rock deformation of different construction methods are obtained by FLAC3D simulation. Combined with the measured data, the settlement of arch roof is controlled during construction. The thickness of the secondary lining is ensured, and the optimum analysis of the reserved amount of the arch roof is carried out for different construction sections with different construction methods, which reduces the construction cost.
【學位授予單位】：北京交通大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U451

【參考文獻】

相關(guān)期刊論文 前10條

1 李鵬飛;張頂立;房倩;侯艷娟;李兵;;變位分配原理在隧道穿越建筑物施工中的應(yīng)用研究[J];北京工業(yè)大學學報;2009年10期

2 侯學淵,廖少明;盾構(gòu)隧道沉降預(yù)估[J];地下工程與隧道;1993年04期

3 沈才華;童立元;;鋼拱架柔性支撐穩(wěn)定性預(yù)測判別方法探討[J];土木工程學報;2007年03期

4 來弘鵬;楊萬精;謝永利;;基于雙洞效應(yīng)的黃土公路隧道地層變形規(guī)律離心模型試驗[J];四川大學學報(工程科學版);2013年04期

5 于學馥;喬端;;軸變論和圍巖穩(wěn)定軸比三規(guī)律[J];有色金屬;1981年03期

6 張新善;廖紅建;張立;;黃土地下隧道開挖對周圍土體變形的影響分析[J];巖石力學與工程學報;2004年S1期

7 張頂立,黃俊;地鐵隧道施工拱頂下沉值的分析與預(yù)測[J];巖石力學與工程學報;2005年10期

8 黃俊,張頂立;地鐵重疊隧道上覆地層變形的數(shù)值模擬[J];巖石力學與工程學報;2005年12期

9 魏綱;張世民;齊靜靜;姚寧;;盾構(gòu)隧道施工引起的地面變形計算方法研究[J];巖石力學與工程學報;2006年S1期

10 王霆;劉維寧;張成滿;何海健;李興高;;地鐵車站淺埋暗挖法施工引起地表沉降規(guī)律研究[J];巖石力學與工程學報;2007年09期

相關(guān)博士學位論文 前2條

1 房倩;高速鐵路隧道支護與圍巖作用關(guān)系研究[D];北京交通大學;2010年

2 陳峰賓;隧道初期支護與軟弱圍巖作用機理及應(yīng)用[D];北京交通大學;2012年

，

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