亚粘土地层大断面隧道台阶七步开挖方法的适应性研究

【作者】 李兵；

【导师】 阳军生； 崔红琴；

【作者基本信息】 中南大学 ， 建筑与土木工程， 2009， 硕士

【摘要】 本论文结合云阳山隧道亚粘土地层洞口段台阶法施工实践,通过该工法应用初期出现的大变形和塌方原因以及后期现场测试结果分析,开展了亚粘土特殊地层条件下大断面隧道台阶七步开挖施工的适应性研究,为完善和推广台阶七步开挖法提供了技术支持,为类似隧道工程提供示范工程和积累经验,主要研究内容包括:1.将台阶七步开挖法引入到云阳山隧道进口段亚粘土地层施工中,综合地层条件、前期掘进施工工艺和相关施工参数,分析了隧道进洞后发生的亚粘土地层隧道塌方原因,提出了有针对性的改进的台阶七步开挖法施工工艺和施工技术参数。2.选取典型隧道断面开展了改进台阶七步开挖施工现场测试,分析了亚粘土地层台阶七步开挖施工围岩与支护体系的变形与受力特性,并对隧道支护结构进行了安全评价,说明了改进台阶七步开挖法在亚粘土地层施工中的适用性。3.通过对改进的台阶七步开挖法在云阳山隧道亚粘土地层施工中的适用性总结,提出了包括开挖方式、核心土尺寸、台阶长度、仰拱封闭时间、加强辅助措施在内的适用于亚粘土地层大断面隧道施工技术指标。4.总结亚粘土地层隧道台阶七步开挖施工具体特点,提出了优化的台阶七步法施工各作业线设备配套选型方案,并给出该工法完整的施工劳动力组织、质量控制、施工安全控制措施以及效益分析评价。更多还原

【Abstract】 Based on construction practices of portal section of Yunyangshan Tunnel in the mild-clay stratum, the applicability of the seven-steps benching method used in the Yunyangshan Tunnel constructed in mild-clay stratum was studied by the field test and analysis of reason about the large deformation and collapse at the early phase. The results will provide the technical support for improving and extending the related construction method, and provide a demonstration project and engineering experiences for similar projects. The contents of main research work include:1. Seven steps benching method was firstly applied in the portal section of Yunyangshan Tunnel constructed in the mild-clay stratum. Base on the general analysis of stratum conditions, construction technics and parameters early adopted, the reason about the large deformation and collapse at the early construction phase, and the improved seven steps method and related technical parameters are brought forward.2. The typical tunnel section was selected and field test related with the seven steps benching method was carried out. The deformation and mechnical characteristcs of the surrounding rockmass and supporting strcture system was studied, and the safety of supporting structure was evaluated. The results indicate that the seven-steps benching method is applicable for the tunnel construction in the mild-clay stratum.3. The applicable conditions of improved seven steps benching method was summarized, and the corresponding construction technical parameters, including excavating manner, dimention of the core soil, bench length, close time of invented arch, strengthened auxiliary construction measures etc, were put forward.4. The study about the equipment matching selection related the seven-step excavation method was carried out, and the optimized equipment matching selection program related seven-step excavation method were proposed. The labor organization of construction, quality control, and control measures of construction safety and evaluation of benefit were presented according to the characteristics of seven-step excavation method.更多还原