高桩墩台桩土共同作用对结构内力的影响*

根据广州某高桩墩台结构断面图和土层参数勘察报告,建立了包含墩台、桩基及土层的三维有限元模型。桩土界面采用面面接触模型,允许桩土分离及滑移,通过接触应力反映桩基土对桩的侧压力和摩阻力。分析得出了高桩墩台在多种荷载组合下的应力场和位移场,以及各桩的弯矩图和轴力图。并进一步将有限元结果与以丰海高桩墩台计算程序为代表的传统嵌固点法计算结果相比较,分析了2种方法单桩轴力图、弯矩图的差异及原因,同时分析了桩基土对结构内力的影响,得到桩排中的最大轴力弯矩桩的位置及单桩上轴力弯矩极值点的位置,为传统的嵌固点法计算结果提供了一些修改与补充,从而为高桩墩台结构设计提供参考。

Influences of pile foundation soil on structural internal force in high-pile pier

According to the soil parameters from the survey report and the structural construction drawings of a high-pile pier in Guangzhou, this paper establishes a three-dimensional finite element model of the highpile pier, including the platform, piles, and soil. The surface-to-surface contact model is used on the pile-soil interface, and it allows separation and slip on the interface. The normal pressure and friction from the soil to the piles are reflected by the contact stress. This paper analyzes and figures out the stress fields and displacement fields of the high-pile pier, as well as the axial force diagram and moment curve of single pile, under various load combinations. Further, this paper compares the finite element method results with the traditional inserting point method results,taking Fenghai high-pile pier computing program for example. The differences of the axial force diagram and moment curve of single pile of both methods are found out and analyzed. Specifically, the impacts of the pile foundation soil on the structure are analyzed. Meanwhile, this paper finds out the pile which has the maximum internal force and the position where the extremum bending moment and axis force appears in a single pile, and provides some modifications and supplements for the results of the traditional inserting point method, which may provide references for structural design of high-pile pier.