洞桩法施作地铁车站下穿桥梁影响研究

发布时间：2018-03-04 11:14

本文选题：地下车站　切入点：下穿桥梁　出处：《北京建筑大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着城市交通的发展,地铁的建设也成为了一个城市进步发展的标志,但建设地铁对周围环境影响较大,尤其是像北京这样立交桥随处可见的城市,这样就出现了地铁下穿桥梁的现象,区间下穿桥梁的例子已经屡见不鲜,但车站下穿桥梁的工程还屈指可数,尤其是浅埋暗挖车站下穿桥梁,一旦出现,就会存在特级风险,因此,研究暗挖车站下穿桥梁已经十分必要。本文以北京地铁六号线一期花园桥站下穿花园桥工程为背景,采用理论研究、数值计算和现场实践的方式进行了研究,主要内容如下： (1)从工程造价、结构安全性、工序转换、降水深度等方面总结对比了洞桩法的七种施工方案； (2)基于桩侧暗挖卸荷理论,并以邓肯张模型在卸荷中考虑土体模量的变化为依据,在Mohr-Coulomb模型中引入邓肯张模型的切线模量和切线泊松比计算公式,以此来考虑开挖卸荷对土层参数的影响,并对此基于FLAC3D进行了二次开发,并用于实际工程计算,与实际监测值进行了对比； (3)利用考虑卸荷影响的M-C模型为土体计算模型,结合花园桥站下穿花园桥工程进行数值模拟计算,得出非对称洞桩法非对称下穿桥梁时地表、桥桩、桥墩的变形规律,并分析了上部桥梁结构的内力变化规律； (4)结合五导洞非对称下穿桥梁的五种工序进行对比分析,提出了合理的施工步序；结合6导洞、5导洞、4导洞、3导洞方案进行分析,得出各种方案下地表及桥墩的变形规律,然后结合横导洞的施工和桥桩加长等四种情况进行分析,得出了最优导洞的数量,说明了横导洞开挖提前施做底板对桥梁的影响规律以及补桩后桥墩的变形规律 (5)提出了注浆加固、围护桩加固、复合锚杆桩隔离、桥桩补强托换、掌子面超前加固等八种加固措施,并对每种措施的加固效果进行了建模分析,综合得出最优措施,并对围护桩加固和复合锚杆桩加固时的桩长进行优化。
[Abstract]:With the development of urban traffic, subway construction has become a symbol of urban progress and development, but subway construction has a great impact on the surrounding environment, especially in cities such as Beijing, where overpasses are everywhere. In this way, there is a phenomenon of undercutting bridges under the subway. Examples of bridge crossing under the interval are common, but there are only a handful of projects to bridge under the station, especially the shallow excavation of the bridge under the station. Once it appears, there will be a special risk. Therefore, it is very necessary to study the undercut bridge under the station. Based on the garden bridge project of the first phase of Beijing Metro Line 6, the research is carried out by means of theoretical research, numerical calculation and field practice. The main contents are as follows:. 1) from the aspects of project cost, structural safety, process conversion, dewatering depth and so on, this paper summarizes and compares seven construction schemes of hole pile method; 2) based on the theory of pile side excavating and unloading, and on the basis of Duncan's model considering the variation of soil modulus in unloading, the tangent modulus and tangent Poisson's ratio of Duncan's model are introduced into Mohr-Coulomb model. The influence of excavation unloading on soil parameters is considered, and the secondary development based on FLAC3D is carried out, which is used in practical engineering calculation and compared with the actual monitoring value. Using M-C model considering the influence of unloading as soil calculation model, combined with the numerical simulation calculation of garden bridge project under garden bridge station, the deformation law of ground surface, bridge pile and pier is obtained when asymmetric hole pile method is used to unsymmetrical underpass bridge. The law of internal force variation of upper bridge structure is also analyzed. In combination with the comparison and analysis of the five processes of asymmetric underpass bridge with five tunnels, the reasonable construction sequence is put forward, and the deformation law of surface and piers under various schemes is obtained by combining with the scheme of No. 6 tunnel, No. 5 tunnel, No. 4 tunnel, No. 4 tunnel, and No. 3 tunnel. Based on the analysis of the construction of the transverse guide tunnel and the lengthening of the bridge pile, the optimal number of the guide holes is obtained, and the influence law of the foundation slab on the bridge and the deformation law of the pier after the pile filling are explained. Eight reinforcement measures, such as grouting reinforcement, enclosing pile reinforcement, composite anchor pile isolation, bridge pile reinforcement and replacement, and forehand face reinforcement, are put forward, and the reinforcement effects of each kind of measures are modeled and analyzed, and the optimal measures are obtained synthetically. The length of the pile is optimized when the retaining pile is strengthened and the composite anchor pile is strengthened.
【学位授予单位】：北京建筑大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U231.4;U445.72

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