基于MARC分析的桩基抗拔动力特性研究

Investigation into Anti-Pulling Dynamic Characteristics of Pile Foundation Based on MARC Analysis

根据支盘桩-土-框架结构动力相互作用的振动台模型试验,采用分析软件Marc对支盘桩和直杆桩体系的抗震性能进行了研究.结果表明:在地震作用下,建筑物的摇摆使支盘桩承受交替变化的拉压荷载,支盘上部土体中的拉"应力泡"随着结构顶层侧移的增大而不断增大,说明上拔力主要是通过支盘传递的,支盘有效地耗散了部分地震能量,减小了上部结构的摆幅.支盘桩的抗拔力由桩侧摩阻力和支盘阻力组成,随着动荷载的增大,支盘成为传递荷载的主要途径.

In this paper,based on the shaking table tests for the dynamic interaction of squeezed disk pile-soilframe structure,the seismic performances of the squeezed disk pile and the straight pile systems are investigated with MARC software. The results show that squeezed disk piles bear alternating pull and compression loads due to the building swing in an earthquake,which produces pull＂stress bubbles＂in disk-upper soil that grow with the la teral displacement of the structure top. It is thus concluded that the uplift force is mainly transferred through the disks that effectively dissipate some seismic energies and reduce the swing of the upper structure. Moreover,it is demonstrated that the anti-pulling force of squeezed disk piles derives from the side friction resistance of the pile and the end resistance of the disks,and that,with the increase of dynamic load,the disk becomes the main way to load transfer.