盾构隧道交叉近接运营地铁隧道地层变形规律及其控制技术研究

发布时间：2018-06-05 19:51

本文选题：红层地层 + 交叉隧道　；参考：《西南交通大学》2017年硕士论文

【摘要】：城市化建设的推进,将地铁建设引入一个新的高潮,地下空间的局限性使得隧道近接情况日趋频繁,因此有必要开展盾构隧道交叉近接运营地铁隧道地层变形规律及其控制技术研究。本文以长沙市轨道交通3号线交叉下穿运营地铁1号线为工程依托,通过数值模拟及现场测试对红层地层盾构交叉近接施工地层变形规律进行分析;通过数值模拟及信息化监测系统的反馈分析对红层地层盾构交叉近接施工控制技术进行研究。得到以下结论:.(1)在红层地层变形规律方面,研究得到在新建隧道拱顶1.5D至地表以及在新建隧道拱顶1D范围内竖向位移随埋深均趋于线性变化,且后者位移随埋深的变化速率较前者提高了 50%左右,速率发生变化是在新建隧道拱顶1D～1.5D的范围内。当先行隧道施工完成,既有管片底部位移占新建隧道拱顶位移的56%,既有隧道拱顶位移占新建隧道拱顶位移的43%,地表位移占新建隧道拱顶位移的28%;同时,右线开挖对左线隧道拱顶上方地中位移造成了不同程度的影响,其影响程度随着埋深的增大而逐渐降低。(2)在盾构掘进参数对地层扰动规律方面,研究得到土舱压力及同步注浆压力的增大均对地层竖向位移起到限制作用。从地表横向位移来看,随着土舱压力的增大位移增长比逐渐趋于平缓,土舱压力在0.24MPa以内变动时对地表竖向位移的限制效果较为明显;同步注浆压力对地表沉降的影响较为显著,位移增长比随同步注浆压力基本呈线性变化,控制同步注浆压力对于控制地表变形起着至关重要的作用。从地表纵向位移来看,随着土舱压力的增大,掌子面前方4倍洞径左右地表有隆起现象,表明当土舱压力过大,会导致前方土体隆起变形,但同步注浆压力对盾构前方的隆陷变形影响不大。(3)从盾构掘进参数对运营地铁隧道结构影响来看,土舱压力及同步注浆压力的增大有助于减小轨道板的不均匀沉降,且土舱压力在0.24MPa以内变动时对既有隧道轨向不均匀沉降的限制是明显的;另外,拱顶弯矩随着土舱压力和同步注浆压力的增大而呈现增大趋势,左侧墙角轴力随着土舱压力和同步注浆压力的增大也呈现增大的趋势,但影响均不明显。(4)从盾构施工控制角度来看,当土舱压力在0.08MPa～0.24MPa时,同步注浆压力在0.2MPa～0.5MPa时,盾构掘进过程中地表隆陷以及既有隧道结构的变形可得到有效控制。
[Abstract]:With the development of urbanization, subway construction is introduced into a new climax, and the limitation of underground space makes the close connection of tunnels become more and more frequent. Therefore, it is necessary to study the ground deformation law and control technology of shield tunnel. In this paper, based on the project of Changsha Metro Line 1, the deformation law of red stratum shield tunneling is analyzed by numerical simulation and field test. Through numerical simulation and feedback analysis of information monitoring system, the construction control technology of shield tunneling in red bed is studied. The following conclusions are obtained: (1) in terms of the deformation law of the red beds, the vertical displacement tends to change linearly with the buried depth from 1.5 D to the surface of the arch roof of the newly built tunnel and 1D range of the arch top of the newly built tunnel. The change rate of the latter displacement with buried depth is about 50% higher than that of the former, and the change of the rate is within the 1D~1.5D range of the new tunnel vault. When the first tunnel construction is completed, the displacement at the bottom of the existing segment accounts for 56 of the displacement of the arch top of the new tunnel, the displacement of the arch top of the existing tunnel occupies 43% of the displacement of the arch top of the new tunnel, and the surface displacement accounts for 28% of the displacement of the arch top of the new tunnel. The excavation of the right line affects the displacement of the ground above the arch of the left tunnel to varying degrees, and the influence degree decreases gradually with the increase of the depth of burying. (2) in the respect of the disturbance law of shield tunneling parameters to the stratum, It is found that the increase of soil chamber pressure and simultaneous grouting pressure limit the vertical displacement of strata. From the point of view of lateral surface displacement, with the increase of soil chamber pressure, the increasing ratio of displacement tends to be gentle, and the effect of limiting vertical displacement is obvious when the soil chamber pressure changes within 0.24MPa. The effect of synchronous grouting pressure on surface subsidence is significant, and the displacement increasing ratio changes linearly with synchronous grouting pressure. Controlling synchronous grouting pressure plays an important role in controlling surface deformation. From the surface longitudinal displacement, with the increase of soil chamber pressure, there is a uplift in the surface around 4 times the diameter of the tunnel in front of the palm, which indicates that if the soil chamber pressure is too large, it will lead to the deformation of the soil uplift in the front. However, the influence of synchronous grouting pressure on the uplift deformation in front of shield tunneling is not significant. According to the influence of shield tunneling parameters on the structure of subway tunnel, the increase of soil chamber pressure and synchronous grouting pressure is helpful to reduce the uneven settlement of track plate. When the earth chamber pressure changes within 0.24MPa, the limit to the uneven settlement of the existing tunnel track is obvious, in addition, the bending moment of the vault increases with the increase of the earth chamber pressure and the synchronous grouting pressure. The axial force of the left corner increases with the increase of soil chamber pressure and synchronous grouting pressure, but the influence is not obvious. From the view of shield construction control, when the earth chamber pressure is in 0.08MPa~0.24MPa, the synchronous grouting pressure is in 0.2MPa~0.5MPa. Surface subsidence and deformation of existing tunnel structures can be effectively controlled during shield tunneling.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.43;U231

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