地震作用下群桩水平动力响应特性及P-Y曲线试验研究

Experimental Study of Horizontal Dynamic Response andP-Y Curves of Piles during Earthquakes

摘要:

目前地震作用下桩基水平动力响应一直是岩土工程界和地震工程领域关注的热点研究问题之一。本文基于振动台试验，通过不同的台面输入波形，引入FBG传感系统对土-群桩—承台结构水平动力响应特性及P-Y曲线主干线变化规律进行研究，并将群桩中各基桩和单桩P-Y曲线主干线与API规范推荐方法进行对比研究。结果表明：对于非液化土试验，各承台的加速度和位移较台面放大倍数普遍不大；饱和砂土试验单桩承台加速度和位移比群桩大2~3倍，群桩承台加速度和位移幅值分别是非液化土的2~3倍；非液化土试验桩基P-Y曲线主干线倾斜度与API规范方法符合较好，而饱和砂土中无论是单桩还是群桩P-Y主干线均需将API规范方法进行适当的折减。

Abstract:

The horizontal dynamic response of pile foundations in liquefiable soil has always been an important research question in the geotechnical field and the field of earthquake engineering.Based on the shaking table test with different input waveforms，the horizontal dynamic interaction responses of the soil-pile-slab system and the variation of the P-Y curve were analyzed using the FBG system.The P-Y curves of each pile in the pile group and single piles were compared with the API specification method.The research results showed that magnification of cap acceleration and displacement was small in general for non-liquefied tests.The cap acceleration and displacement of single piles were 2 to 3 times greater than for piles in the pile group，while the cap acceleration and displacement of piles in the pile group were 2 to 3 times greater than for non-liquefied cases.The slope of the P-Y curve for non-liquefied tests agreed well with the API specification method; however，the P-Y curves for both single piles and piles in the group were needed to reduce the API method appropriately in saturated soil.