深水特大型沉井基础施工技术研究

发布时间：2018-03-24 04:16

本文选题：深水沉井基础　切入点：沉井浮运　出处：《西南交通大学》2017年硕士论文

【摘要】：随着交通事业的日益发展,需要修建宽广的跨越江河湖海的深水大跨桥梁,而作为大跨深水桥梁经常使用的主要大型基础结构形式之一的沉井基础,具有非常广泛的应用前景。目前,随着桥梁跨度的发展,深水沉井基础趋于大型化,其结构构造和工艺技术面临日益复杂的问题,在我国更有许多桥梁沉井尺度达到创世界纪录的空前水平,缺少可借鉴成熟经验,需要结合工程实际项目展开特大型深水沉井工艺技术研究。鉴于此,本文依托建设中的沪通长江大桥主塔沉井基础工程,对特大型深水沉井关键工艺技术展开研究。在总结桥梁大型沉井技术基础上,依托工程实际,主要研究了以下问题:1、研究了沉井浮运、下沉定位系统、沉井监控系统。同时探讨了在不同的水流速度、风速、不同的吃水深度等工况下沉井浮运时的水流阻力及空气阻力的情况。进行了对"钢锚桩+重力锚"的半刚性体系的计算分析,并且提出了许多具体的定位措施。2、通过沉井的施工全过程的监测分析,提出了进行沉井施工的一些技术与方法。研究表明,在沉井浮运过程中,不能忽略沉井迎风面的空气阻力以及井孔内壁面的空气阻力,随着沉井浮运的速度变大,圆角矩形沉井内壁的挡水作用发挥得比较明显;沉井的定位需考虑河床冲刷和水流扰动影响,而采用"钢锚桩+重力锚"的半刚性体系可以实现快速准确定位、操作方便;在沉井全过程的监控系统中,运用基于GPS-RTK技术的实时几何姿态监控系统,可以实现沉井施工的姿态和安全监测预报。
[Abstract]:With the development of transportation, it is necessary to build a wide deep water bridge across rivers, lakes and seas, and as one of the main large infrastructure forms, the caisson foundation is often used in the long span deep water bridge. At present, with the development of bridge span, the foundation of deep water caisson tends to be large, and its structural structure and technology face more and more complicated problems. In China, there are many bridges whose caisson scale has reached the unprecedented level of world record, lacking of mature experience, so it is necessary to carry out the technical research of super large deep water caisson technology in combination with practical engineering projects. Based on the main tower caisson foundation of the Hutong Yangtze River Bridge under construction, this paper studies the key technology of super large deep water caisson. On the basis of summing up the bridge large caisson technology, the paper relies on the engineering practice. This paper mainly studied the following question: 1, studied the floating, sinking positioning system, caisson monitoring system, and discussed the different flow velocity, wind speed, The flow resistance and air resistance of caisson floating under different draught conditions are analyzed. The semi-rigid system of "gravity anchor of steel anchor pile" is calculated and analyzed. Through monitoring and analyzing the whole process of caisson construction, some techniques and methods of caisson construction are put forward. The research shows that, in the process of floating operation of caisson, The air resistance of the upwind surface of the caisson and the air resistance of the inner wall of the borehole can not be ignored. With the increase of the floating velocity of the caisson, the water retaining effect of the inner wall of the circular rectangular caisson is obvious. The influence of river bed erosion and flow disturbance should be taken into account in the positioning of the caisson, and the semi-rigid system with "steel anchor pile gravity anchor" can be used to locate the caisson quickly and accurately, which is convenient to operate, and in the monitoring system of the whole process of the caisson, By using the real-time geometric attitude monitoring system based on GPS-RTK technology, the attitude and safety monitoring and prediction of caisson construction can be realized.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U445.557

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