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大跨高边墙地铁风道洞桩法施工力学机理分析
Analysis on Mechanical Mechanism of Tunnel-Pile Method Construction for Large Span and High Sidewall Metro Ventilation Tunnel
【作者】 庞宇斌;
【导师】 李兆平;
【作者基本信息】 北京交通大学 , 建筑与土木工程, 2012, 硕士
【摘要】 洞桩法施工是一个将传统的地面明挖施工方法和暗挖法之间进行有机结合。洞桩法在提前施作好的边桩和拱部初支的保护下,暗挖土体并施作二衬结构。与过去所采用的浅埋暗挖法相比,洞桩法施工灵活,能较好的控制地表沉降,满足城市复杂的工程环境的要求,具有很大的技术优势。本文以地铁十四号线地铁将台站风道为依托工程,结合现场勘察资料和有限元计算,对洞桩法施工进行研究。研究内容如下:1.对CRD法和洞桩法进行了有限元计算分析,得出两种工法施工所引起的地层变形情况,并对两种工法的安全性、造价和工期等方面进行了对比分析,以选择合适的施工方法。2.对洞桩法三种不同的二衬施做顺序进行了有限元计算分析,得出不同二衬施工顺序的地层位移和顶拱初衬内力值的变化规律,并对三种工法的安全性、施工质量、造价等方面进行对比分析,以选择合理的施工顺序。3.洞桩法逆作法工况下,采用荷载—结构模型对结构施工过程中的五个工况进行了计算分析,以选出施工中结构二衬的不利工况。4.洞桩法逆作法工况下,通过有限元计算,研究围护桩不同桩径、不同的入土深度时的地表沉降、拱部初期支护和围护桩的变形规律。将钻孔桩与人工挖孔桩在适用范围、施工工艺、施工安全、施工质量、工期和造价等方面进行了对比,以选择合适的挖孔方式及入土深度。
【Abstract】 Tunnel-Pile Method Construction is the organic combination of Open-cut Foundation Pit Method and Mining Method. The soils cut under the protection of piles and beam and arc. Compared with the traditional method of shallow tunnel construction which is used in the past, Tunnel-Pile Method Construction is more flexible, and it has a better restriction of Ground surface settlement, so this method satisfies the demand of the complex construction environment in the city, and enjoys a great technological advantage.Taking the Metro Ventilation Tunnel of Jiangtai subway station of Line fourteen as actual background, in this dissertation, Tunnel-Pile Method Construction is researched combined with the Investigation data and FEM calculation. The main works includes:1. Finite-element analysis is taken on both CRD Method and Tunnel-Pile Method Construction to obtain the Ground displacement which is caused by the two methods. Compare the security, the cost of construction, the construction period of the two methods, and choose a reasonable one subsequent.2. Conduct FEM calculation and analysis of the three Secondary-lining Construction sequence of Tunnel-Pile Method Construction to obtain the variation of the Ground displacement and the Top arch lining internal force of the different Secondary-lining Construction sequence, compare the security, the cost of construction, the construction period of the three methods to choose a reasonable one subsequent.3. Calculate and analyze the five Working conditions of the construction process under the circumstances of Tunnel-Pile Inverse method using Load-structure model, and confirm the Adverse Working conditions of the Secondary-lining in the construction.4. Research the variation of the Ground displacement、The initial support of arch and Enclosure piles under the different Pile diameter and Buried depth of the Enclosure piles based on the Tunnel-Pile Inverse method Working condition. Compared the scope of application、construction technology、Inverse method and the construction period of the Bored pile and the artificial hole-digging pile, and choose the appropriate Drilling mode。
【Key words】 Tunnel-Pile Method; CRD method; Hole pile; finite element method;