桥梁桩基竖向承载能力测试及桩土相互作用的数值模拟分析

发布时间：2018-11-25 19:16

【摘要】：桥梁作为交通线中的重要组成部分,它跨越江河湖海和深沟峡谷,使天堑变通途。桩基础作为桥跨结构的重要组成部分,随着桥梁建筑物向超大跨、重载方向的发展,桩基础凭借承载能力大、沉降小、施工方便以及对各种复杂地质条件的适应性强等优点成为基础设计中首选的基础形式。在上部结构传递的荷载作用下,桩基础不仅需要提供足够的承载能力,同时需要控制沉降的大小以保证上部结构对变形限值的要求。因此,对桩基础的竖向承载特性进行研究显得至关重要。鉴于此,本文主要做了如下工作并得到了相应的结论:1、总结概括了桩基础的应用和发展历史、桩基承载能力测试的一般方法和桩土相互作用的研究现状,为合理选择桩基竖向承载能力试验方法和运用有限元准确模拟桩土相互作用提供理论依据。2、对桩基础的竖向承载特性,包括单桩竖向荷载作用下的传递机理、单桩的侧阻力发挥机理、单桩的端阻力发挥机理以及单桩承载能力的影响因素(桩周土体的性质、桩体的几何特性和桩体材料)等进行了详细的分析,为优化桩基设计提供参考。3、以新建成兰铁路土建施工第10标段太平站四线大桥和解放村双线大桥的桩基础设计和施工为依托,通过现场试验进行了 3根试桩的桩基竖向承载能力的测试,试验采用锚桩静载试验方法和慢速维持荷载法,得到地层的基本承载力、桩周极限摩阻力等各种土层参数,通过荷载～沉降曲线确定单桩的竖向承载能力,验证进行摩擦桩设计的可行性,为桩基设计提供依据。4、结合ABAQUS有限元软件对桩基础的竖向承载能力进行模拟分析,并将分级荷载作用下的结果与现场实测结果进行对比分析,验证了运用ABAQUS进行桩土相互作用的模拟分析的适用性和合理性,并且,通过分析不同桩径和桩长情况下桩基的承载特性,确定了该地层情况下的合理桩基尺寸,从而优化桩基设计,降低施工难度和工程造价。
[Abstract]:As an important part of traffic line, bridge crosses rivers, lakes and deep gullies and canyons. Pile foundation is an important part of bridge span structure. With the development of bridge building towards super span and heavy load, pile foundation has large bearing capacity and small settlement. The advantages of convenient construction and strong adaptability to various complicated geological conditions become the preferred foundation form in foundation design. Under the load transfer of the superstructure, the pile foundation not only needs to provide enough bearing capacity, but also needs to control the settlement to ensure the deformation limit of the superstructure. Therefore, it is very important to study the vertical bearing characteristics of pile foundation. In view of this, this paper mainly does the following work and obtains the corresponding conclusion: 1, summarizes the pile foundation application and the development history, the pile foundation bearing capacity test general method and the pile-soil interaction research present situation, This paper provides a theoretical basis for reasonably selecting the test method of vertical bearing capacity of pile foundation and accurately simulating pile-soil interaction by using finite element method. 2. The vertical bearing characteristics of pile foundation, including the transfer mechanism of single pile under vertical load, are discussed. The exertion mechanism of side resistance of single pile, the mechanism of end resistance of single pile and the influencing factors of bearing capacity of single pile (properties of soil around pile, geometric characteristics of pile and material of pile body) are analyzed in detail. For optimizing the design of pile foundation. 3. Based on the design and construction of pile foundation of Taiping Station fourth Line Bridge and Jiefangcun double Line Bridge, The vertical bearing capacity of three test piles was tested by field test. The static load test method of anchor pile and the slow maintenance load method were used to obtain the basic bearing capacity of the stratum, the limit friction around the pile and other soil parameters. The vertical bearing capacity of single pile is determined by load-settlement curve, and the feasibility of friction pile design is verified. 4. Combined with ABAQUS finite element software, the vertical bearing capacity of pile foundation is simulated and analyzed. The comparison between the results under graded load and the field measured results proves the applicability and reasonableness of the pile-soil interaction simulation analysis using ABAQUS. By analyzing the bearing characteristics of pile foundation under different diameter and length of pile, the reasonable size of pile foundation is determined in this paper, so as to optimize the design of pile foundation, reduce the construction difficulty and engineering cost.
【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】：U443.15

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