变截面与软流塑地层地铁渡线隧道施工技术研究

【作者】 李红岩；

【导师】 彭立敏； 李志勇；

【作者基本信息】 中南大学 ， 建筑与土木工程， 2007， 硕士

【摘要】 当地铁隧道处在软弱富水的地层条件、大跨度变截面的工程施工条件、地表建筑物林立，地下管网密布等的工程边界条件时，其施工过程将非常复杂。国内外针对这方面问题的理论研究才刚刚开始，滞后的理论研究和蓬勃发展的此类工程实践很不相称。本文以南京地铁一期工程的鼓楼站-玄武门站区间隧道工程实例为基础，对大断面、变截面软流塑地铁区间隧道施工技术进行了较为系统的研究和探讨，主要完成了以下工作：1．对大跨度变截面洞室群施工，进行了施工方案设计与比选。研究结果表明：应根据断面大小来确定大断面、变截面隧道的施工方法；断面由小到大开挖方案对施工更为有利。2．对软流塑地层区段施工，进行了施工方案设计与比选。研究结果表明：对软流塑地层区段隧道采用台阶分步开挖法施工，并按大管棚以及小导管超前预注浆加固地层，可成功通过软流塑地层，有效控制地面沉降。3．通过对地铁隧道施工过程的弹塑性有限元模拟分析，研究了大断面、变截面软流塑地铁区间隧道在开挖、支护过程位移场等的变化情况，获取了最优施工方法及一些力学性状参数，为设计和施工提供了依据和指导。4．通过施工监测分析，得出该工程施工过程中引起的地表沉降和拱顶下沉量均在控制范围内，围岩压力和支护受力变形遵循“急剧变化--缓慢变化--基本稳定”的变形规律，说明本工程采用的支护结构的强度和刚度是合理有效的，施工方案和施工措施是安全可行的。本文的研究成果已应用于实际工程，并取得了显著的经济效益和社会效益，对其他类似工程有重要参考价值。更多还原

【Abstract】 When it is in the condition of abundant groundwater, weak stratum, large span, changeable section, and the top-building or the ground pipe is in great numbers that the subway construction process will be much more complex. Research on this problem is just begun in China at present. So the correlate theory gets behind of flourishing subway construction. Based on Nanjing NO.1 project Gulou-Xuwu subway practice, this paper focus on subway construction technology under great and changeable section, soft plastic-flow stratum condition. The main contents are as followings:1. Construction method is compared and elected to the subway structure which has large span and changeable section. Results show that it is better according to the section are, that is, the small section is firstly excavated firstly then the bigger one.2. Construction under soft flow-plastic stratum is simulated. Results indicate that it is effective on controlling the ground drop when adopting sidesteps method with shed advancing and injecting.3. The best construction parameters are acquired through elastic-plastic FEM numerical simulation after analyzing the displacement change in the process of subway excavation, and it can provide instruction for subway design and construction in similar instance.4. the ground and vault displacement are both in the range of control through monitoring data, and the rule that rock stress and lining internal force is ’sharp change-slowness change-stabilization’. The data shows that lining is appropriate, and construction measure is safety.The above research has been applied in practice and has received notable mechanic and social benefit, which also has important reference for similar subway.更多还原