【作者】 李林；

【导师】 姜忻良；

【作者基本信息】 天津大学 ， 结构工程， 2009， 硕士

【摘要】 在盾构掘进中,如何控制盾构掘进引起地层移动,保证隧道周围以及临近建筑物的安全,是设计以及施工过程中必须考虑的主要问题。本课题以广州地铁二、八号延长线工程为背景,在广州洛溪-南洲区间进行了隧道开挖过程中地层沉降与倾斜的现场试验。在隧道左线里程ZDK8+164.437m ~ ZDK8+182.437m范围处,分别在隧道开挖轴线上方、斜上方布设测点,以测得土层的变形情况,得到了隧道轴线上方以及在开挖沉降槽范围内土层的竖直沉降以及水平位移。通过现场实测,分析总结了广州地铁盾构施工过程中周围土体的变形规律,并利用有限元软件ABAQUS建立了三维有限元动态开挖模型,对盾构隧道动态开挖过程进行了模拟,计算结果表明,与实测结果吻合良好。现场实测与理论计算结果均表明,随着盾构的向前推进,地表产生先隆起、后凹陷、最终稍稍回弹的趋势。对于地表竖向位移来说,引起的前方隆起和后方沉降最大扰动区域发生在盾前33m至盾后30.5m的区域,该区域应作为工程施工过程中地层形变控制的重点。同时,在此模型的基础上,进一步建立了盾构穿越桩群的有限元模型,得到了三种工况下的沉降槽曲线,分析了盾构掘进对桩群及上方建筑物的影响。双隧道在不同的施工工序下,无论桩基存在与否,两条隧道齐头并进同时向前开挖所产生的地表沉降都是最不利的,因此,应尽量避免双隧道同时施工,以防止产生应力重叠现象。更多还原

【Abstract】 Controling the ground movement, ensuring the safety of adjacent buildings are the main point in the process of tunnel designing and construsting. The ground settlements and the disturbance of soil around tunnel by shield driven are summarized by means of measurement of Guangzhou No.2/8 extending subway line project. The observation points were arranged around the tunnel during the left tunnel mileage ZDK8+164.437m ~ ZDK8+182.437m to measure the disturbance of each layer. According to the actual engineering, a 3D FEM model is proposed to simulate the excavating of shield tunnel by means of general FEM program ABAQUS, which puts forward to imitate moving-forward shield process. And the results of simulation are matching the experimental data satisfactorily.Both field test and theoretical arithmetic are showing that the ground are presenting the tendency of uplift-subside-little springback. The disturbed area of maximal uplift and subsiding are taking place 33m in front of the excaved surface and 30.5m behind the surface, which are supposed to be top-priority ground controlling during tunnel excavation.Meanwhile, the finite model of tunnel passing through pile group was built based on suitable parameter, providing the settlement curve of three conditions and the effection to pile group and buildings. Under the different working conditions, it is the worst for the ground settlement that two tunnels excavation at the same time no matter whether the pile group exists. Consequently, it should be avoided as possible to avert stress overlapping.更多还原