地震导致的土体液化侧移，使得轴横向受荷桩的受力与变形十分复杂。根据桩周土体的液化程度将基桩分为非液化段、液化段和嵌固段，建立考虑桩土相互作用的简化受力模型。结合土体液化侧移模式以及基桩受荷特点，推导各特征桩段的挠曲变形微分方程，并给出相应的幂级数解答。通过与试验测试结果进行对比，检验本文方法的合理性。在此基础上，探讨土体液化侧移量、荷载分布形式以及嵌固深度等对基桩的影响。分析发现：土体液化侧移量每增加30cm，基桩桩顶水平位移增加5.8mm，桩身最大弯矩增大95.6kN·m ；与竖向荷载相比，横向荷载对基桩的影响更大，横向荷载每增大50％，桩顶水平位移及桩身最大弯矩分别增加65％和54％，但基桩的“P-Δ”效应也不容忽视；改善基桩的嵌固深度可以提高基桩的抗震性能，但到达一定深度后，其效果并不明显。%The stressed forces and deformations of piles under axial and lateral loads will become very complex w hen considering lateral displacements of liquefied soil mass caused by earthquake .In this paper ,the founda-tion pile was divided into the non-liquidizing section ,liquidizing section and embedded section according to the liquidizing degree of the surrounding soil mass and the simplification model of pile-soil interaction was estab-lished .The differential equations of bending deformations of all characteristic sections of the pile shaft were de-rived by analyzing the lateral displacements mode of liquefied soil mass and the mechanical characteristics of the loaded foundation pile ,and the corresponding power series solution were given .The solutions were verified by test results .Influence of liquefied soil mass displacements ,load distributions and embedded depths etc .on the foundation pile was further discussed .The analysis indicates as follows :For every 30cm increase of the lateral displacement of the liquefied soil mass ,the lateral displacement of the pile head increases by 5.8mm and the maximum bending moment of the pile shaft increases by 95.6 kN · m ;compared with vertical loads ,lateral loads impose greater influence on the foundation pile ,i .e .,w henever the lateral load increases by 50% ,the lateral displacement of the pile head and the maximum bending moment of the pile shaft increase by about 65%and 54% respectively ;the"P-Δ"effects are not allowed to be ignored ;lengthening of the embedded depth can improve the seismic behavior of the foundation pile ,however upon reaching a certain depth ,the improving effect becomes unobtainable .
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