盾构隧道垂直下穿既有管线的扰动效应研究

发布时间：2018-11-21 07:41

【摘要】：盾构隧道对周围环境的影响成为重要的研究课题,其中盾构对周围管线的影响问题尤为突出。目前,针对盾构隧道对周围管线影响的研究还存在薄弱环节,多数研究仅考虑单一因素对管线变形的影响。本文针对影响管线位移的主要因素进行敏感性分析,为实际工程的设计施工提供参考依据。运用弹性地基梁理论,对隧道施工引起地层和管线变形机理进行了探讨;分析了刚性接口管线和柔性接口管线受隧道垂直下穿扰动的力学效应,提出了管线变形与受力的预计方法。利用FLAC3D有限差分数值模拟结合实测结果综合分析了双线隧道施工对管线和地表沉降的规律:左线隧道施工后,地表横向沉降槽与管线位移曲线均符合高斯分布,管线与地表最大沉降均处于左线隧道中心正上方;右线隧道开挖完成后,地表和管线的主要沉降范围变大。地表的沉降特征近似符合高斯分布,沉降较左线隧道施工后增大,两隧道中心沉降曲线较为平缓,最大沉降变至两隧道之间;管线沉降呈现“一峰两谷”形,不符合高斯分布,管线最大沉降值靠近左线隧道。数值模拟研究了六个主要因素对管线沉降的影响规律:随着管线覆土深度、隧道掘进速率和隧道直径的增加,管线竖向位移和最大沉降逐渐变大;随着管线直径、开挖面支护压力比和管隧间距的增大,管线竖向位移和最大沉降逐渐减小;随着隧道掘进速率和隧道直径的增加,管线的主要沉降范围也有所增大。管线最大沉降量与覆土深度、开挖面支护压力比、隧道直径近似呈线性关系。以管线最大沉降为指标,采用灰色关联分析方法,对各因素的影响敏感性进行了对比研究,以对管线沉降影响的敏感性由强到弱依次为:隧道直径、管隧间距、管线直径、管线覆土深度、开挖面支护压力比、隧道掘进速率。
[Abstract]:The influence of shield tunneling on the surrounding environment has become an important research topic, in which the influence of shield tunneling on the surrounding pipeline is particularly prominent. At present, there is still a weak link in the study of the influence of shield tunnel on the surrounding pipeline, and most of the studies only consider the influence of a single factor on the pipeline deformation. In this paper, sensitivity analysis of the main factors affecting pipeline displacement is carried out, which provides a reference for the design and construction of practical engineering. Based on the theory of elastic foundation beam, the deformation mechanism of stratum and pipeline caused by tunnel construction is discussed. The mechanical effect of rigid interface pipeline and flexible interface pipeline subjected to vertical perturbing disturbance of tunnel is analyzed, and the prediction method of pipeline deformation and force is put forward. By using FLAC3D finite difference numerical simulation combined with the measured results, the law of pipeline and surface subsidence in two-line tunnel construction is comprehensively analyzed: after the construction of the left tunnel, the lateral settlement trough and the displacement curve of the pipeline conform to Gao Si's distribution. The maximum settlement of pipeline and surface is directly above the center of left tunnel. After the excavation of the right-line tunnel, the main settlement range of the surface and pipeline becomes larger. The settlement characteristics of the surface approximately accord with Gao Si distribution, the settlement is larger than that of the left tunnel, the center settlement curve of the two tunnels is relatively gentle, and the maximum settlement changes between the two tunnels. The settlement of pipeline is "one peak and two valleys", which does not accord with Gao Si distribution, and the maximum settlement value of pipeline is close to the left tunnel. The influence of six main factors on pipeline settlement is studied by numerical simulation. With the increase of tunnel tunneling speed and tunnel diameter, the vertical displacement and maximum settlement of pipeline become larger with the depth of overburden of pipeline, tunnel tunneling rate and tunnel diameter. The vertical displacement and maximum settlement of the pipeline gradually decrease with the increase of the diameter of pipeline, the pressure ratio of excavated surface support and the distance between pipes and tunnels, and the main settlement range of pipeline increases with the increase of tunneling speed and diameter. The maximum settlement of pipeline is linearly related to the depth of overlying soil, the ratio of support pressure to excavating surface, and the diameter of tunnel. Taking the maximum settlement of pipeline as the index and adopting the method of grey correlation analysis, the influence sensitivity of each factor is compared and studied. The order of sensitivity to the influence of pipeline settlement from strong to weak is: tunnel diameter, tunnel spacing, pipeline diameter, and so on. Pipeline overlying depth, excavating surface support pressure ratio, tunneling rate.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.43;TU990.3

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