软基浅埋隧道施工技术研究

【作者】 史胜利；

【导师】 彭立敏； 洪开荣；

【作者基本信息】 中南大学 ， 建筑与土木工程， 2007， 硕士

【摘要】 本文以下穿公路的软基浅埋段的牛岭界隧道实际工程为依托，根据隧道现场监测资料，结合理论分析和数值仿真计算，重点探讨双下侧导坑的施工工艺，研究其受力特性，并分析在浅埋软弱段进行台阶法施工的可行性。主要研究内容如下：(1)分析牛岭界隧道在下穿既有二级公路浅埋软基段的双下侧导坑的受力特性，优化其施工工艺，制定相关辅助施工的组织管理及工艺；建立隧道施工期坍塌的应急预案及响应措施、下穿公路的二级应急预案及响应措施。(2)分析牛岭界隧道在穿过既有公路后的浅埋软基段的台阶法施工的可行性，建立软基浅埋段的隧道初期支护的力学模型，计算了不同埋深的围岩压力，并同泰沙基松弛荷载理论进行了比较，分析了影响初期支护沉降的因素，研究了不同台阶长度、不同围岩抗力系数下，初期支护的沉降规律，确定了初期支护地合理尺寸；结论表明，在穿过既有公路段后的软弱围岩段，采用台阶法施工是可行的，也是经济合理的。(3)应用数值计算方法，分析了下穿既有公路段的上下台阶法及双下侧壁导坑法的施工，通过对洞周位移、开挖面受力、结构受力的比较，得出双下侧导坑施工的合理性，并优化了双下侧导坑的合理基础宽度。(4)制定牛岭界隧道的监控量测原则，分析台阶法及双下侧导坑的部分量测结果，并与数值模拟结果进行对比研究。目前牛岭界隧道工程已经竣工通车，表明本文提出的施工方法及工艺是合理的，并取得了显著的经济价值和社会效应，具有重大的工程意义，可为其它类似的工程提供重要的参考价值。更多还原

【Abstract】 This disseration combined with a shallow tunnel in soft foundation named Niulingjie Tunnel beneath the existing road. The construction schedule of double-side-wall drift, its stress characteristic and analyzed the feasibility of excavation in shallow-buried soft rock with benching technique are studied with the field measuring data, theoretical analyses and numerical simulation. The main content includes followings:Firstly, stress characteristic of Niulingjie Tunnel is analyzed; construction technology to establish correlative construction management and technology and emergency response plan when tunnel collapses during construction is optimized.Secondly, the feasibility of benching technique in the soft foundation is analyzed when the tunnel passes through the exiting road; surrounding rock pressure with different burial depth through creating a mechanic model is calculated; the affecting factors on settlement of early support is analyzed; the settlement regularities of early support with different bench length and rock resistant coefficient is studied, and reasonable dimension for early support is established. Results imply the plan is viable and economical.Thirdly, benching tunneling method and double-side-wall drift are simulated by FLAC-2D. Compared with the surrounding rock deformation of the two conditions, it is found that the second one is more reasonable.Finally, the principle of monitoring and measurement for Niulingjie Tunnel is put forward, some measurement results from two construction methods are analyzed by constrast to numerical results.Now Niulingjie Tunnel has been built and put into operatrion, it shows that the construction method and technology raised in this disseration is reasonable and make a remarkable economy value and social effect. It can also provide some reference value to other similar projects.更多还原