【作者】 吴为义；

【导师】 张土乔；

【作者基本信息】 浙江大学 ， 市政工程， 2008， 博士

【摘要】 盾构隧道施工对周围地下管线的影响问题是地铁建设中的一项难题,也是城市环境土工问题的重要内容,对本课题进行研究具有一定的理论意义与实用价值。本文主要采用理论分析、工程实测分析与数值模拟相结合的方法,对管周土压力与管土相互作用、柔性接口管线的变形机理与位移计算、盾构隧道周围地下管线位移的实测分析、地下管线性状的理论与数值计算、管线性状的影响因素分析及管线对隧道周围土体位移场的影响等方面进行了研究。本文的主要研究内容如下:(1)基于工程实测数据,按管隧垂直、管隧平行两种情形,分别研究了单隧道与双隧道施工时地下管线在盾构到达前、盾构到达、盾构通过时、盾尾通过后与后续固结沉降等五个阶段的位移历时变化规律及沿管线纵向的位移分布规律。(2)针对现有管周土压力计算方法的不足,在现场试验的基础上,研究了管土相互作用问题,建立了管底土压力分布计算模型。同时,基于现场试验分析了柔性接口管线的竖向变形机理问题,给出了柔性接口管线的竖向位移计算解析模型。(3)根据弹性地基理论及前人研究基础,按管隧垂直、管隧平行两种情形,分别给出了隧道周围刚性与柔性接口地下管线的竖向位移计算公式,通过与其它计算公式的结果进行比较,说明了本文公式的合理性。并结合算例,对其参数敏感性进行了初步分析,可用于工程计算或验证数值分析结果。(4)对工程实例进行了计算对比分析,验证了有限差分数值方法模拟本课题的合理性与可靠性。运用所建模型,按管隧垂直、管隧平行两种情形比较分析了盾构隧道周围刚性管线与柔性管线的力学性状;也模拟了柔性接口管线的性状特征,得出了一些有别于刚性接口管线的规律。(5)采用数值计算方法,按管隧垂直、管隧平行两种情形,较为详细地分析了土质、管线的直径、壁厚、截面形状、材质、管隧垂直间距、管隧水平间距、隧洞直径、开挖面位置、超挖量、开挖面支护压力、掘进速率、地层应力释放率及双线隧道中心间距等因素对地下管线力学性状的影响规律。此外,还分析了在有内压作用、管底发生脱空、受工作井影响等特殊工况下管线力学性状的变化情况。为地铁工程建设中实施科学保护地下管线提供了一定的理论依据。(6)根据工程实例与数值计算结果,按管隧垂直、管隧平行两种情形,比较研究了地下管线的存在对盾构隧道周围土体竖向位移场分布的影响规律。更多还原

【Abstract】 Assessing the impact on the pipelines around tunnel induced by shield tunneling is an arduous problem, which is also one of the most important research subjects in civil and environmental engineering research area. Giving a study on this research subject has important theoretical consequences and utility value. This paper gave comprehensive study on the measured displacement patterns of buried pipelines, the soil pressure around the pipe and pipe soil interaction, the deformation mechanism and displacement of flexible jointed pipes, the theory analysis and numerical simulation of the buried pipelines, the parameter study that influence the pipes’ mechanics and the soil displacement field around the tunnel caused by the pipelines, by using the methods of on-site test, numerical simulation and theory study. The main research contents are as follows:（1）Through analysis of large numbers of on-site measured data, the single tunnel and double tunnel was studied, according to two cases, one is pipe transverse to tunnel and the other is pipe parallel to the tunnel. The displacement curve with time of the pipelines during the five stages about before shield arriving, shield arriving, after shield passing, shield tail passing and continued consolidation settlement was given.（2）According to the shortcoming of calculating the soil pressure around the pipe at present, the pipe soil interaction was studied to give a soil pressure distribution model around pipe, based on the on-site test. At the same time, the vertical deformation mechanism of flexible jointed pipes was studied, and the vertical displacement model of flexible jointed pipes was given.（3）Based on the elastic foundation beam theory and previous research foundation, the vertical displacement analysis model of the rigid and flexible jointed pipes were given. Compared with the results of other formula, this paper’s formula gave more reasonable results and could be applied in engineering calculation and for verifying the numerical results. By using this formula, the parameter sensitivity analysis was done.（4）The numerical results were compared with the on-site test data, which show great reasonability and probability for using the FLAC^3D to simulate the complex pipe-soil-tunnel interaction. According to the different cases （pipe transverse to tunnel and pipe parallel to the tunnel）, the corresponding finite difference analysis models were build up to analyze the displacement and force mechanics of the rigid and flexible jointed pipes around the tunnel. We simulated the displacement and force mechanics of flexible jointed pipes successfully, and obtained some phenomenon, which are different from the rigid jointed pipes.（5）Using the finite difference software FLAC^3D, the pipe transverse to tunnel case and the pipe parallel to the tunnel case were simulated individually. The parameters such as soil type, pipe diameter, pipe thickness, pipe section shape, pipe material, distance between the pipe and tunnel, tunnel diameter, excavation surface location, extra excavation amount, supporting pressure, driving velocity, ground stress release rate and distance of the double tunnel, which would affect the mechanics of buried pipelines, were studied. In addition, the influences of the shield tunneling under special situations such as the internal pressure of the pipe, the pipe supporting losting, were also studied. The research results offer credible theoretical foundation for pipelines protection during the shield tunneling construction.（6）According to the engineering example and numerical results, the influence of the soil vertical displacement distribution around the tunnel due to the existence of pipelines was studied, under the pipe transverse to tunnel case and pipe parallel to the tunnel case.更多还原