陡坡段桥梁基桩屈曲稳定性分析方法研究

发布时间：2018-02-11 02:12

本文关键词： 桩基础陡坡屈曲能量法数值模拟影响因素　出处：《湖南大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着我国西部大开发战略的大力推进，山区高速公路、铁路建设得到飞速发展。受山区复杂地形地貌及工程水文地质条件的限制，不少桥梁基桩不得不修建于陡坡地段。陡坡段桥梁基桩，，既要承受桩顶竖向及水平荷载，还要受到来自坡体的剩余下滑力以及承受岩(土)体地基抗力作用，受力特性十分复杂。此外，由于陡坡段基桩通常自由段长度大，使其稳定性问题更加突出，常规设计方法难以满足工程实际的需要。因此，本文针对陡坡段桥梁基桩工程环境的特殊性、承载机理的复杂性，提出了一套符合其受力特性的稳定性分析方法，以期为陡坡段桥梁基桩的屈曲稳定分析提供参考。本文首先深入研究了陡坡段桥梁基桩受力特性及屈曲机理，对比分析了其与常规基桩的主要区别，重点考虑了“陡坡效应”对基桩的影响。在此基础上，考虑桩后坡体剩余下滑力分布规律及桩前岩土体水平地基抗力弱化效应对基桩稳定性的影响，建立了陡坡段桥梁基桩屈曲稳定分析计算模型；其次，基于能量法建立了桩-坡体系的总势能方程，结合变分原理，导得了陡坡段桥梁基桩屈曲稳定的特征方程，通过MATLAB编程求解，得到了陡坡段桥梁基桩屈曲稳定临界荷载及其稳定计算长度的解答，并利用相关试验验证了本文理论计算方法。再次，以实际工程为例，运用ADINA有限元分析软件，综合考虑了陡坡段桥梁基桩的受力特点及桩-土相互作用规律，建立了陡坡段桥梁基桩屈曲稳定分析的二维数值计算模型。通过对模型进行求解，得到了相应的陡坡段桥梁基桩屈曲临界荷载，并与理论计算结果相互验证。最后，运用本文提出的理论与数值计算方法，结合某工程实例，深入分析了桩身弹性模量、桩径、嵌固深度、变截面情况、土体分层及桩身倾斜等施工缺陷对陡坡段桥梁基桩屈曲稳定性的影响。
[Abstract]:With the great development of western China, the construction of highway and railway in mountainous area has been developed rapidly, which is restricted by the complex terrain and geomorphology of mountain area and the hydrogeological conditions of engineering. Many bridge piles have to be built on steep slopes. In steep slopes, bridge piles not only bear vertical and horizontal loads on the top of the pile, but also are subjected to the residual sliding force from the slope body and to the resistance of the rock (soil) foundation. The mechanical characteristics are very complicated. In addition, because of the large length of pile foundation in steep slope section, the stability problem is more prominent, and the conventional design method is difficult to meet the needs of engineering practice. In view of the particularity of the engineering environment and the complexity of the bearing mechanism of bridge foundation pile in steep slope section, a set of stability analysis methods according to its stress characteristics are put forward in this paper, in order to provide a reference for buckling stability analysis of bridge foundation pile in steep slope section. In this paper, the stress characteristics and buckling mechanism of bridge foundation pile in steep slope section are studied, the main differences between the pile and the conventional pile are analyzed, and the influence of "steep slope effect" on foundation pile is considered. Considering the distribution of residual sliding force and the influence of the weakening effect of the horizontal foundation resistance on the stability of the foundation pile, a calculation model for the buckling stability of the bridge foundation pile in steep slope section is established. Secondly, based on the energy method, the total potential energy equation of pile-slope system is established. Combined with the variational principle, the characteristic equation of buckling stability of bridge foundation pile in steep slope section is derived and solved by MATLAB programming. The solution of the buckling stability critical load and the calculated length of the pile stability of the bridge foundation in steep slope section is obtained, and the theoretical calculation method is verified by the relevant tests. Thirdly, taking the actual project as an example, using ADINA finite element analysis software, considering the stress characteristics and pile-soil interaction law of bridge foundation pile in steep slope section synthetically. A two-dimensional numerical model for buckling stability analysis of bridge foundation pile in steep slope section is established. The critical buckling load of bridge foundation pile in steep slope section is obtained by solving the model, and the theoretical results are verified. Finally, using the theory and numerical calculation method proposed in this paper, combined with an engineering example, the elastic modulus of pile body, pile diameter, embedded depth and variable cross-section are deeply analyzed. The influence of soil layer and pile inclination on the buckling stability of bridge foundation pile in steep slope section.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U443.15

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