被动式桥梁桩基托换方案研究与应用

发布时间：2018-07-05 09:14

本文选题：桩基托换 + 设计理论　；参考：《兰州交通大学》2015年硕士论文

【摘要】：随着城市向大型化、现代化方向发展,城市的地面交通压力越来越大,为了缓解地面交通压力,建设高效、便捷的地下铁道成为众多城市改善交通状况的首选,同时地下铁道的发达程度也成为衡量一座城市现代化的重要指标。地铁隧道的建设与既有建筑物基础的冲突无法避免,这就需要对侵入隧道内的桩基进行托换。桩基托换往往与隧道的施工是密不可分的,因此研究隧道施工过程中桩基托换的力学行为具有重要的现实意义。本文首先介绍基础托换的几种分类方法、托换桩的主要类型和特点、托换承重体系的主要类型,然后阐述了国内外托换工程研究现状和重要实例以及基础托换过程中应注意的几个问题。对桩基托换的设计理论进行了详细阐述,重点归纳了桩基托换结构设计的难点和重点,给出了托换结构各部件的设计方法,着重分析了托换梁和托换新桩节点设计的思路以及托换梁与托换柱节点的抗剪机理,并对桩基托换的施工监测体系进行详细说明。对兰州市地铁一号线拱星墩~焦家湾区间隧道下穿烂泥沟桥的工程概况以及数值分析中的有限元的相关理论作了介绍,对隧道直接下穿烂泥沟桥的开挖以及切桩过程进行了较为详细的数值模拟分析,分析了隧道开挖和切桩过程桩基和土层的力学行为,并从控制沉降的角度分析,得出隧道直接下穿烂泥沟桥梁引起的结构沉降不满足规范要求,必须对烂泥沟桥梁进行加固或改造。对烂泥沟桥的加固或改造工程提出了三种可行性方案,最后采用对比分析的方法,得出被动式桩基托换方案为最佳方案。对烂泥沟地面桩基托换洞内截桩的被动式桩基托换施工过程进行了详细的数值模拟分析,从沉降、应力以及内力方面对计算结果进行分析,证明了该托换方案是合理、可行的。
[Abstract]:With the development of city towards large scale and modernization, the pressure of urban ground traffic is increasing. In order to alleviate the pressure of ground traffic, the construction of efficient and convenient underground railway has become the first choice for many cities to improve the traffic condition. At the same time, the development of subway has become an important indicator to measure the modernization of a city. The conflict between the subway tunnel construction and the existing building foundation cannot be avoided, so it is necessary to replace the pile foundation that intrudes into the tunnel. Pile foundation underpinning is often closely related to tunnel construction, so it is of great practical significance to study the mechanical behavior of pile foundation underpinning during tunnel construction. This paper first introduces several classification methods of foundation underpinning, the main types and characteristics of underpinning piles, the main types of underpinning load bearing system, Then the present situation and important examples of underpinning engineering at home and abroad and some problems needing attention in the process of foundational underpinning are expounded. The design theory of pile foundation underpinning is expounded in detail. The difficulties and key points of pile foundation underpinning structure design are summarized, and the design methods of various components of pile foundation underpinning structure are given. The paper emphatically analyzes the design idea of the supporting beam and the new pile joint, and the shear mechanism of the underpinning beam and the underpinning column joint, and explains in detail the construction monitoring system of the pile foundation underpinning. This paper introduces the engineering situation of the tunnel under the tunnel between the arch star pier and the Jiaojiawan section of Lanzhou Metro Line 1 through the muddy ditch bridge and the relevant theory of the finite element method in the numerical analysis. The excavation and pile cutting process of tunnel directly through muddy ditch bridge are simulated and analyzed in detail. The mechanical behavior of pile foundation and soil layer during tunnel excavation and pile cutting are analyzed, and the settlement control is analyzed from the point of view of controlling settlement. It is concluded that the structural settlement caused by the tunnel directly passing through the muddy ditch bridge does not meet the requirements of the code, so it is necessary to strengthen or rebuild the muddy ditch bridge. In this paper, three feasible schemes are put forward for the reinforcement or reconstruction of the muddy ditch bridge. Finally, by using the method of comparative analysis, it is concluded that the passive pile foundation underpinning scheme is the best scheme. In this paper, the numerical simulation analysis of the construction process of the passive pile foundation underpinning in the retaining tunnel of the ground pile foundation in the muddy ditch is carried out, and the calculation results are analyzed from the aspects of settlement, stress and internal force. It is proved that the replacement scheme is reasonable and feasible.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U445.551

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