山区斜坡段桥梁基桩屈曲稳定性分析

摘要

By considering the mechanical response of piles and the weakening effect of soil in front of piles, a calculation method was proposed for buckling analysis of bridge piles in slopes. Total potential energy equation of the pile-soil system was established, where buckling critical load and stability calculation length were derived by using energy method. Compared with model test results, the feasibility of the proposed method was verified. In addition, the parametric studies were conducted by FEM, such as elastic modulus, diameter, free length, and embedded depth of piles. The results show that diameter and embedded ratio are closely related to quality of the stability, but little related with elastic modulus conversely.%根据山区斜坡段桥梁基桩的承载机理，考虑桩前岩土体弱化效应，建立斜坡段桥梁基桩屈曲稳定性分析简化计算模型；建立山区斜坡段桥梁基桩桩−坡体系的总势能方程，并利用能量原理及变分法进行求解，导出基桩屈曲临界荷载及稳定计算长度公式；然后，通过与模型试验结果进行对比分析，验证理论解答的可行性；结合有限元法探讨桩身弹性模量、自由段长度、桩径以及嵌固深度等因素对某实体工程桩稳定性的影响。研究结果表明：基桩存在一临界嵌固深度；桩径及埋入比对基桩稳定性影响较大；弹性模量对基桩稳定性影响较小。