某桥梁桩基础的抗震计算研究

Seismic Calculation and Analysis of the Pile Foundation of a Certain Bridge

当前桩基础的抗震设计仅采取构造措施来保证其抗震性能,有可能会过高或过低地估计桩基础的抗震性能。针对某桥梁桩基础的抗震设计,建立全桥的三维有限元模型,计算在桩-土-结构共同工作情况下桩基础的地震响应,通过输入不同地震波来进行对比分析,并对结果进行复核,得出:(1)桩身内力响应与所输入地震动的频谱特性有关,桩身沿横桥方向的内力最大;(2)对于该场地的桥梁桩基础,桩-土-结构共同工作的有限元分析结果与m法结果差别不大;(3)当承台埋深为0时,桩身内力基本都偏大,要对承台侧土体做相应的加固处理。

The seismic performance of the pile foundations of bridges is very important in earth quake and geotechnical engineering. At present, the seismic design of a pile foundation only con siders structural measures to ensure its seismic performance, which can lead to overestimation or underestimation of the seismic performance. Therefore, this study investigates the seismic design of a bridge using a three dimensional finite element model. Under different seismic waves, the seismic response of a pile foundation was calculated, considering the soil pile structure interac tion, and the results were compared and checked. The results show that： （1） The internal force response of the pile is related to the frequency spectrum characteristics of the input ground mo tion; （2） for the pile foundation in a site, the result of finite element analysis is similar to that of the m method; （3） when the depth of pile cap is zero, the internal force of the pile body is relatively large, so it is necessary to take corresponding measures to reinforce the soil around the pile cap.