陡坡高桥墩-双桩结构体系承载机理及其稳定性计算方法研究

The bearing mechanism and stability analysis of single row high pier-double pile system is the new research project facing the mountain steep bridge construction.Therefore,it has more important theoretical and practical significance to carry out related research .This study are as follows: firstly,the bearing mechanism of steep single row of high pier-double pile is investigated by carring out the model experiment. Secondly, the method manifold method will be used in numerical test, and the bearing behavior influence factor analysis of steep slope single row high pier -double pile structure system under the action of load will be carried out. By analysing stress field and rock displacement field distribution of pile-structure system, energy transfer mechanism,the calculation method of energy spread boundary can be established by deriving energy fiffusion boundary. based of this, with the catastrophe theory and energy theory, the instability mechanism and failure mode of steep slope single row high pier- double pile structure system under the action of load can be solved by solving the structure displacement model, energy diffusion boundary, energy equation and the judgment of catastrophe model. The stability analysis calculation method of steep slope single row high bridge pier-double pile will be established by determing the instability criterion to perfect the steep slope single row high pier - double pile structure design theory. Finally, with the use of model tests and numerical results to validate the theory of rational methods ,which can perfect the steep slope single row high pier - double pile structure design theory.

单排高桥墩-双桩结构体系承载机理与稳定性分析是山区陡坡段桥梁建设所面临的新课题。因此，开展相关问题研究具有重要理论与实际意义。本研究内容如下：首先，开展室内模型试验，探讨陡坡单排高桥墩-双桩结构体系承载机理；其次，引入数值流形元方法，在解决桩-岩接触准则、参数取值等科学问题后，进行陡坡单排高桥墩-双桩结构体系稳定性影响因素分析；然后，结合模型试验与数值分析，深入探讨桩-岩结构体系应力场与位移场分布规律、能量传递机理，推求其能量扩散边界，建立桩-岩结构体系能量扩散边界计算方法。在此基础上，引入突变理论与能量原理，研究结构体系位移发展模式、能量扩散边界、能量方程建立、突变失稳类型与准则等关键问题，揭示陡坡单排高桥墩-双桩结构体系突变失稳机理，提出陡坡单排高桥墩-双桩结构体系稳定性计算新方法；最后，利用模型试验与数值分析结果，验证理论方法的合理性，完善陡坡段单排高桥墩-双桩结构体系设计理论。

陡坡高桥墩-桩基结构体系受力环境相比常规桩基更为复杂与特殊，给工程设计与施工带来一系列新的技术难题，因此，如何确保陡坡段单排高桥墩-双桩结构体系设计合理与施工安全成为山区桥梁建设的关键，而深入探讨其竖向荷载下承载机理与稳定性计算方法具有重要的理论与工程实际意义。项目重点开展了四方面研究：①陡坡单排高桥墩-双桩结构体系承载机理室内模型试验研究；②陡坡单排高桥墩-双桩结构体系能量扩散边界计算方法研究；③陡坡高桥墩-双桩结构体系屈曲稳定计算方法研究；④陡坡单排高桥墩-双桩结构体系屈曲稳定计算参数确定与影响因素分析。项目研究成果主要包括：基于室内模型试验研究成果，初步明确了陡坡单排高桥墩-双桩结构体系承载机理。通过数值试验研究获得了陡坡单排高桥墩-双桩结构体系的影响因素规律；建立了基于能量原理与突变理论的陡坡高桥墩-双桩结构体系屈曲稳定计算方法；提出了横向荷载作用下斜坡桩的可靠性分析方法；建立了水平荷载作用下斜坡刚性桩非线性分析方法 ; 同时提出一套陡坡高桥墩-双桩结构体系桩基内力位移计算方法。