山区桩柱式桥梁基桩水平变形可靠性分析研究

Reliability analysis of horizontal displacement of a pile beneath column-supported bridge located in mountainous area

为研究桩柱式桥梁基桩水平变形及其可靠性。首先,分析了山区桩柱式桥梁基桩的承载特性,建立了相应的简化受力模型及挠曲微分方程,并对其进行求解得到了基桩内力与位移计算的表达式;在此基础上,分析了影响基桩水平变形的主要因素,建立了桩柱式桥梁基桩水平变形可靠度计算极限状态方程,并借助验算点法对其进行求解,得到了基桩水平变形可靠度指标及失效概率指标的计算表达式;最后,以某桥梁基桩为例,利用该方法计算了可靠度指标,对比分析表明,该方法与改进响应面法及蒙特卡罗法计算结果吻合较好,验证了该计算方法的可行性。

The displacement and the relevant reliability of a pile beneath column-supported bridge are investigated. Firstly, the bearing characteristics of the bridge pile in mountainous area are analyzed, and its differential equations are established and solved, by which the internal force and displacement along the pile shaft are obtained. Secondly, the main influence factors for the horizontal displacement are analyzed. Based on the displacement distribution solved by the limit state equations, the reliability index and failure probability indexes are solved by the checking point method. Finally, an real case of a bridge pile is analyzed by the proposed method, and the results agree well with those of the improved response surface method and Monte Carlo method.