【作者】 刘齐建；

【导师】 曹喜仁； 赵明华；

【作者基本信息】 湖南大学 ， 岩土工程， 2002， 硕士

【摘要】 桩基础是一种常用的桥梁基础型式，具有承载力高、稳定性好、沉降量小而均匀、便于机械化施工及适用性强等特点。在目前桥梁桩基设计计算中，存在许多不完善之处，有待进一步研究。本文在已有理论基础上，对按桩顶沉降量计算基桩竖向承载力的方法进行了研究，并对洞庭湖区大直径桥梁基桩竖向承载力进行了试验研究。 本文首先对桩基础进行了概述，介绍了桥梁基桩竖向承载力研究的发展简况和意义。对竖向荷载作用下基桩的受力性状及破坏机理进行了分析，然后介绍了基桩竖向承载力常用计算方法。根据目前的研究现状，对大直径灌注桩的受力性状和竖向承载力的确定进行了简单的探讨。针对目前桥梁基桩竖向承载力的常规分析方法，指出了其中所存在的问题。 本文针对大直径嵌岩灌注桩的竖向承载力计算，提出了一种即简单又符合实际情况的荷载传递计算模型。该模型不仅能考虑桩周土的非线性特性，还能考虑桩底土体的非线性及沉渣的影响。依照该模型，推导了均质土和层状土中的大直径灌注桩的竖向承载力的计算公式，得到了按桩顶沉降量控制基桩竖向承载力理论的解析解，并编写了计算程序，可根据桩顶沉降量直接得到作用在桩顶的竖向荷载。 本文详细介绍了茅草街大桥试验桩的大型竖向静载荷试验，得到了一系列试验成果。详细分析了洞庭湖区大直径桥梁基桩的受力特性，并提出了可供实际工程应用的洞庭湖区大直径桥梁基桩桩侧摩阻力推荐值，指出了桥梁基桩的设计中应注意的问题。 本文还就计算理论与实测资料进行了对比分析，结果表明二者基本吻合。更多还原

【Abstract】 As the commonly used foundations in the bridge engineering, large-diameter bored piles have many advantages, such as high bearing capacity, good stability, little and homogeneous vertical settlement, facility for mechanician construction and good applicability. Some aspects of the current design and calculation methods are still imperfect and to be developed. According to the settlement of the pile top, the vertical bearing capacity theory is analyzed herein.In this paper, the load behaviour and failure machanism of pile under axial load is analyzed, and the conventional calculation methods with their limitations are summarized. Based on the current theory, a set of load transfer model is proposed and the formulas of calculating the load capacity of the pile embedded in homogeneous or layered soil with their program are derived herein. The good agreement between the results and in-site test data indicates that the proposed calculation theory is accurate and reliable which can calculate the axial load applied at pile top according to the settlement of the pile top and reflect the load transfer behaviour.Sponsered by Hunan Provincial Communications Department, a great in-site static pile test is carried out for the Maocaojie bridge, which is introduceded in details in this paper. From the test, some results with value of theory and practice are obtained about the axial laod capacity of large-diameter bored bridge piles in the area of Dongtinghu lake.更多还原