大型复杂桥梁施工过程动态控制与管理技术研究

发布时间：2018-11-12 10:48

【摘要】：随着国家交通基础设施建设步伐的加快,大型复杂桥梁的建设数量与建设规模与日俱增,然而大型桥梁施工中的问题也逐渐凸现出来。在桥梁施工过程中,每一个施工阶段,结构的线形都在发生变化,结构的各个部位的受力也在发生变化。大型复杂桥梁的施工控制是连接设计和施工的重要环节,也是大型复杂桥梁建设中难度较大的工作,大型复杂桥梁施工过程控制质量对成桥状态和建设质量起着决定性的作用。本文以国内跨径最大的预应力混凝土矮塔斜拉桥——商登高速郑州航空港境段跨南水北调总干渠矮塔斜拉桥(以下简称为“南水北调斜拉桥”)为工程背景,跟踪大桥的施工全过程,针对大桥主墩承台、主梁、斜拉索和索塔等主要构件的施工质量展开研究,以此指导大桥的施工,主要研究内容如下:(1)阐述了大型复杂桥梁施工过程控制的重要意义,分别针对斜拉桥和矮塔斜拉桥的发展状况及各自的代表性桥梁进行了总结归纳,并对大体积混凝土施工质量控制、大型复杂桥梁特别是斜拉桥的上部结构控制理论的研究现状进行了分析。(2)以南水北调斜拉桥主墩承台尺寸、混凝土配合比方案、拟定的施工方法、冷管位置等为工程背景,建立了基于水化热分析的有限元模型,分析了其在不同时段内温度场、应力场分布情况,并且选取了代表性的节点考察大体积混凝土承台浇筑完成后不同时段内外温度差值、特殊部位的应力及其容许拉应力强度发展趋势,判断裂缝发展情况;研究分析了大体积混凝土温度场、应力场分布情况对混凝土浇筑入模温度、对流边界条件、冷管冷却水流速的敏感性。(3)建立了南水北调斜拉桥有限元仿真模型,根据拟定的施工组织设计,选取最大悬臂状态、边跨合龙、中跨合龙等工况,重点分析了主梁的内力、应力、变形以及索塔的位移、斜拉索索力的仿真结果,并且根据有限元仿真分析结果,提供了各节段主梁的立模标高,为施工控制提供理论依据与指导。(4)将自适应控制理论应用于南水北调斜拉桥的上部结构施工控制中,制定实施了具体的监测方案,包括线形监测、应力监测、温度监测等,给出了针对每项监测内容的具体实施方法、实施手段。(5)针对自适应施工控制理论中的参数识别部分,分别介绍了不同的识别方法及其原理,并且进行了对比,最后选取神经网络作为本桥自适应施工控制中的参数识别方法,设计了三层BP神经网络模型,利用训练样本数据及鉴定样本数据对其进行训练和验证,结果表明采用BP神经网络进行南水北调斜拉桥参数识别的误差结果在可接受范围之内,说明采用设计的BP神经网络具有可行性。
[Abstract]:With the acceleration of the construction of national transportation infrastructure, the number and scale of large and complex bridges are increasing day by day. However, the problems in the construction of large bridges are also gradually emerging. In the process of bridge construction, the line shape of the structure is changing in every construction stage, and the stress on each part of the structure is also changing. The construction control of large complex bridges is an important link in connection design and construction, and it is also a difficult task in the construction of large complex bridges. The construction process control quality of large complex bridges plays a decisive role in the state of bridge construction and the quality of construction. In this paper, the project background is the cable-stayed bridge with the prestressed concrete tower, which is the largest span in China, which is called "the cable-stayed bridge of the South-to-North Water transfer Project", which spans the main trunk canal of the main channel of the South-to-North Water transfer Project (hereinafter referred to as the "South-to-North Water transfer Cable-Stayed Bridge"). Tracking the whole construction process of the bridge, aiming at the construction quality of the main pier cap, girder, stay cable and cable tower of the bridge, so as to guide the construction of the bridge. The main research contents are as follows: (1) the significance of construction process control of large and complex bridges is expounded, and the development of cable-stayed bridges and low-tower cable-stayed bridges and their representative bridges are summarized and summarized respectively. This paper also analyzes the present situation of the research on the quality control of mass concrete construction and the superstructure control theory of large and complex bridges, especially cable-stayed bridges. (2) the size of the main pier cap and the concrete mix ratio of the cable-stayed bridge of South-to-North Water transfer Project are analyzed. Based on the proposed construction method and cold pipe location, a finite element model based on hydration heat analysis is established, and the distribution of temperature field and stress field in different periods is analyzed. At the same time, the representative nodes are selected to investigate the temperature difference between inside and outside, the stress and the allowable tensile stress intensity development trend of special position after the completion of mass concrete cap construction, and to judge the development of cracks. The sensitivity of mass concrete temperature field and stress field distribution to pouring temperature, convection boundary condition and cooling water velocity of cold pipe is studied and analyzed. (3) the finite element simulation model of South-to-North Water transfer Cable-Stayed Bridge is established. According to the proposed construction organization design, the maximum cantilever state, the side span closure, the middle span closure and so on are selected. The simulation results of the internal force, stress, deformation, displacement of the cable tower and cable force of the cable are emphatically analyzed. According to the results of finite element simulation analysis, the vertical formwork elevation of each section of main girder is provided, which provides theoretical basis and guidance for construction control. (4) the adaptive control theory is applied to the construction control of the upper structure of the cable-stayed bridge of South-to-North Water transfer Project. The specific monitoring program is established and implemented, including linear monitoring, stress monitoring, temperature monitoring and so on. The specific implementation methods for each monitoring content are given. (5) according to the parameter identification part of the adaptive construction control theory, the different identification methods and their principles are introduced, and the comparison is made. Finally, the neural network is selected as the parameter identification method in the adaptive construction control of the bridge, and a three-layer BP neural network model is designed, which is trained and verified by the training sample data and the identification sample data. The results show that the error result of parameter identification of the cable-stayed bridge of South-to-North Water transfer using BP neural network is within the acceptable range, which indicates the feasibility of using the designed BP neural network.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U445

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