【作者】 朱季；

【导师】 唐晓武；

【作者基本信息】 浙江大学 ， 岩土工程， 2010， 硕士

【摘要】 盾构法作为地铁隧道施工中一种最主要的施工方法已在我国得到广泛应用。土压平衡盾构施工的安全性控制以及施工所引起的环境变化是盾构隧道设计和施工中非常关心的问题,由于粉砂土性质介于砂土和粘土之间,其在盾构施工过程中表现出的工程特性难以掌握,因此在粉砂土地基中该问题显得尤为突出。本文的主要研究工作包括:(1)针对土压平衡盾构双线隧道施工引起的周边土体环境变化进行了现场实测。测试结果表明,土体中孔隙水压力随着盾构掘进呈锯齿形的上升下降变化,后掘进隧道对先掘进隧道具有挤压作用,合理的注浆参量有利于控制盾构隧道周围的土体变形。(2)分析了土压平衡盾构施工中盾构与土体的相互作用,通过Mindlin解进行坐标转化,推导了刀盘和土体之间的摩擦所引起的土体变形计算公式,修正了土体损失引起的土体变形计算公式,完善了盾构施工引起的地表变形计算公式,验证了刀盘扭矩引起地表沉降非对称分布的现象,该方法适合于施工阶段。(3)利用三维有限差分法对在饱和粉砂土地基中土压平衡盾构在施工状态下的稳定性问题进行了研究,得出了饱和粉砂土地基施工状态下盾构开挖面的极限支护压力设置范围,并分析了隧道埋深、地下水位、停机时间以及土体性质对盾构开挖面极限支护压力的影响。本文通过现场实测总结了粉砂土地基中双线盾构隧道施工引起的周围土体环境变化规律,利用基于Mindlin解推导的盾构施工地表变形公式分析了盾构施工引起的土体变形,并通过数值分析方法得出了粉砂土地基中盾构开挖面极限支护压力的设置范围,为粉砂土地基中的盾构隧道施工安全提供了参考。更多还原

【Abstract】 The shield tunneling method, as one of the main construction methods of metro tunneling, has been used widely in China. The safety control of excavation face and variation of soil environment induced by shield tunneling is the main issue during shield tunnel design and construction. Because the property of sandy silt is usually between that of sand and that of clay, it is hard for engineers to understand the engineering property of sandy silt during shield tunneling. The main research contents are as follows:(1) Relevant in-situ measurement is executed during Hangzhou metro tunneling in sandy silt. From the results, it is concluded that variation of pore pressure against distance is a Zigzag-shape distribution against distance. The latter shield tunneling has thrust influence on earlier shield tunneling, and reasonable grouting helps to control soil deformation around shield tunnel.(2) The interaction between soil and shield is analyzed. The formulation of soil deformation induced by torque between soil and cutterhead is obtained derived from Mindlin solution which could verify the phenomenon that the settlement trough is assymmetric. By revising formulation of soil deformation induced by soil loss, the total formulation of soil deformation is obtained which is useful in construction stage.(3) A three-dimensional fast Lagrangian differential finite element method is used to simulate the deformation and failure of excavation face considering the influence of ground water. The limited face pressure of excavation face is obtained by a great deal of analysis, and the influence of tunnel depth, the depth of ground level, time of shield stopping and soil property is also analyzed by using numerical model.In this thesis, the variation regularity of soil stress and deformation induced by parallel shield tunneling is concluded by field measurements, and surface settlement is analyzed by formulation derived from Mindlin solution, and the set range of face pressure in sandy silt is obtained by numerical analysis. All of the conclusions provide some relevant suggestion for shield tunneling in sandy silt.更多还原