地震荷载下长短桩复合地基的群桩效应系数分析

长短桩复合地基中,地震发生时,短桩在降低长桩所受剪力和弯矩影响中起到重要作用。本研究对弹性地基中的钢管桩基础实行了静态有限元分析,以及动态离心模型试验,通过桩径、桩长、桩间距等参数进行剪切波速,长桩剪力弯矩的对比分析,得到一种新的水平向群桩效应系数计算方法,并通过对模型建筑物的模拟,验证了该方法的有效性与实用性。结果表明,静态有限元数值模拟分析和离心模型试验结果有较好拟合,不同震级作用下通过该方法均能给出较为合理的系数。本文结果可为长短桩复合桩基的抗震性能提供重要参考,实际工程中,通过调整桩径,桩长,短桩数量等参数,可以提出更为合理的设计施工方案。

Analysis of group pile effect coefficient of long-short pile composite foundation under earthquake load

In the long-short pile composite foundations,short piles play an important role to reduce the influence of shear and bending moments on long piles when the earthquake take places.In this study,static finite element analysis and dynamic centrifugal model tests are carried out on the steel pipe pile foundation in the elastic foundation,and the comparative analysis of the shear wave velocity and the shear bending moment of the long pile is carried out through the parameters such as pile diameter,pile length,and pile spacing.A new method to calculate the horizontal group pile effect coefficient has been obtained,and the effectiveness and practicability of the method are verified through the simulation of model buildings.The result shows that the static finite element numerical simulation analysis and the centrifugal model test result have a good fit,and this method can give a more reasonable coefficient under the action of different seismic magnitudes.The research result can provide an important reference for the seismic performance of long-short pile composite foundation.In actual engineering,a more reasonable design and construction plan can be proposed by adjusting parameters such as pile diameter,pile length,and number of short piles.