大直径桩基承载特性的仿真试验研究

发布时间：2019-01-04 11:11

【摘要】：随着我国工程建设事业的蓬勃发展，大直径钻孔灌注桩在各种大型的桥梁、高层建筑和高速公路中得到了较为广泛的使用，但大直径钻孔灌注桩的理论研究还相对较为缺乏，尤其在实际工程中，桩基承载力的确定往往是通过单桩静载荷试验或者自平衡测试法获得，由于考虑到工程造价、荷载箱放置位置等原因，施加的荷载往往不足以使测试桩进入破坏状态，试桩资料虽然可以满足工程需求，但影响了其研究价值。本文在吉林省交通厅项目《大桥软岩桩基承载力评价方法研究》（2011-1-11）的基础上，以仿真分析方法为基础，对大直径钻孔灌注桩的承载特性进行分析研究，本文的研究对完善大直径钻孔灌注桩的理论研究和指导实际工程具有一定的意义和价值。在对大直径桩基承载力评价方法研究的基础上，采用仿真分析方法对单桩抗压静载荷试验和自平衡试验中单桩的承载特性进行仿真模拟，对大直径桩在不同试验方法下荷载沉降曲线的特征、桩身轴力的变化等方面进行分析，并对影响大直径钻孔灌注桩的承载特性的各种因素进行了系统的研究。建立基于BP神经网络的接触面力学参数的反分析模型，对桩土接触面的力学参数进行反分析研究。基于荷载传递理论的双曲线模型，从理论上推导出自平衡试验中单桩荷载与沉降的关系，，在此基础上，利用模拟分析程序对自平衡试验中“平衡点”位置进行讨论，从而为自平衡试验设计提供参考。
[Abstract]:With the rapid development of engineering construction in China, large-diameter bored piles have been widely used in various large bridges, high-rise buildings and highways, but the theoretical research of large-diameter bored piles is relatively lacking. Especially in practical engineering, the bearing capacity of pile foundation is usually determined by single pile static load test or self-balance test, because of considering the project cost, load box placement and other reasons, The load applied is often not enough to make the test pile enter into the state of failure. Although the test pile data can meet the needs of the project, the research value of the test pile is affected. In this paper, on the basis of Jilin Provincial Communications Department project "study on bearing capacity of soft Rock pile Foundation of Bridge" (2011-1-11), the bearing capacity characteristics of large-diameter bored pile are analyzed and studied on the basis of simulation analysis method. The research in this paper has certain significance and value for perfecting the theoretical research of large diameter bored pile and guiding the practical project. On the basis of the research on the evaluation method of bearing capacity of large diameter pile foundation, the bearing capacity characteristics of single pile in static load test and self balance test are simulated by simulation analysis method. The characteristics of load settlement curve of large diameter pile under different test methods and the variation of axial force of pile body are analyzed, and various factors affecting bearing characteristics of large diameter bored pile are systematically studied. The back analysis model of mechanical parameters of contact surface based on BP neural network is established, and the mechanical parameters of pile-soil interface are studied. Based on the hyperbolic model of load transfer theory, the relationship between single pile load and settlement in self-equilibrium test is derived theoretically. On this basis, the position of "equilibrium point" in self-equilibrium test is discussed by means of simulation analysis program. Thus, reference is provided for the design of self-balancing test.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU473.11

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