既有隧道上方挖方近接施工影响及对策研究

发布时间：2018-03-28 20:09

  本文选题：既有隧道上方挖方　切入点：模型试验　出处：《西南交通大学》2015年硕士论文

【摘要】：随着我国国民经济的快速发展,对交通基础设施的需求也在不断增加。公路、铁路得到快速发展,而城市地铁、城市下穿隧道的修建己成为缓解城市交通压力的重要手段。随着交通建设工程的增加,不可避免的存在在既有隧道上方进行挖方类工程的情况。而当初始埋深较小时,挖方类工程就会对既有隧道产生近接影响。本文依托于国家自然基金项目“既有隧道上方挖填方施工的影响分区及对策研究”。通过模型试验、数值模拟和现场测试,研究了围岩等级、隧道结构健全度、初始埋深对既有隧道的影响规律,得出既有隧道上方挖方影响程度分区,结合实际工程案例提出施工对策,并在工程实例中进行运用。(1)模型试验中,用相似材料模拟Ⅳ级、V级和Ⅵ级围岩分别在PVC管和钢管模拟既有隧道衬砌的情况下挖方过程,采用3.6D、2.4D和1.1D三种初始埋深进行试验。(2)数值模拟对模型试验进行补充和验证,通过数值模拟和模型试验结果对比,找出挖方过程中位移、围岩压力和结构应力增量变化规律,总结出既有隧道上方挖方过程中围岩等级、隧道健全度和初始埋深等主要因素的影响规律。(3)以不同健全度隧道允许应力增量为标准对模型试验结果进行影响分区,分别对初始埋深3.6D、2.4D和1.1D的情况进行影响分区的划分,同时考虑围岩等级和隧道健全度对分区界限的修正。通过引入残留埋深比,对不同初始埋深影响分界进行分析,得到统一影响分区,提出围岩等级和隧道健全度修正影响分区的方法。(4)从既有隧道、中间地层和新建工程三个方面,提出既有隧道上方挖方工程施工对策。判定连霍高速改扩建工程为强影响,采用梁板加固方案,现场监测结果证明施工过程隧道变形和受力正常。
[Abstract]:With the rapid development of China's national economy, the demand for transportation infrastructure is also increasing. Roads and railways are developing rapidly, while urban subways, The construction of urban underpass tunnel has become an important means to relieve urban traffic pressure. With the increase of traffic construction projects, it is inevitable to carry out excavation projects above the existing tunnels. However, when the initial burial depth is small, Excavation projects will have a close connection effect on existing tunnels. This paper relies on the National Natural Fund project "study on the influence zones and Countermeasures of excavation and filling Construction above existing tunnels." through model tests, numerical simulation and field tests, The influence law of surrounding rock grade, tunnel structure soundness and initial burial depth on the existing tunnel is studied. The influence degree zoning of excavation above the existing tunnel is obtained, and the construction countermeasures are put forward in combination with the actual engineering cases. In the application of the model test, the excavation process of grade 鈪，

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