不同厚度液化土层大直径变截面六桩基础振动台模型试验研究  

Experimental study on shaking table model of six piles with large diameter and variable section in different thickened soil layers

作　　者：冯忠居[1] 李元鹏 王伟 张聪[1] 李宗海 赵瑞欣 王思琦 FENG Zhongju;LI Yuanpeng;WANG Wei;ZHANG Cong;LI Zonghai;ZHAO Ruixin;WANG Siqi(School of Highway,Chang’an University,Xi’an 710064,China;Xiamen Road and Bridge Engineering Investment and Development Co.,Ltd.,Xiamen 361026,China)

机构地区：[1]长安大学公路学院,陕西西安710064 [2]厦门路桥工程投资发展有限公司,福建厦门361026

出　　处：《振动工程学报》2025年第3期595-603,共9页Journal of Vibration Engineering

基　　金：福建省交通运输科技项目(202105)。

摘　　要：为研究不同厚度液化土层大直径变截面六桩基础动力响应特性,依托厦门第二东通道翔安大桥实体工程,通过室内振动台模型试验,选取地震动强度分别为0.15g、0.25g、0.35g、0.45g的5010波,开展液化土层厚度分别为30、40、50 cm时饱和砂土孔压比、大直径变截面六桩基础的桩身加速度、桩身弯矩、桩顶水平位移的动力特性研究。结果表明:不同饱和砂土层厚度下,大直径变截面六桩基础的桩身加速度及弯矩在变截面和土层分界面处发生突变;同一土层厚度下,随着地震动强度从0.15g增大到0.45g,饱和砂土孔压比、六桩基础的桩身加速度、桩顶水平位移、桩身弯矩均增大;0.15g地震动强度下,随着饱和砂土层厚度增大,饱和砂土孔压比稳定值减小,但六桩基础的桩顶水平位移、桩身加速度及弯矩峰值均逐渐增大且增幅变大。建议在液化场地大直径变截面桩基础设计时,应特别考虑大直径变截面六桩基础在不同液化土层厚度下的动力响应差异,并注重变截面和土层分界面的抗弯性能,以保证六桩基础的抗震性能。In order to study the dynamic response characteristics of six-pile foundation with large diameter and variable section in different layers of liquefied soil,5010 waves with ground motion intensity of 0.15g,0.25g,0.35g and 0.45g are selected through indoor shaking table model test based on the solid project of Xiangan Bridge in Xiamen Second East Passage.The dynamic characteristics of saturated sand pore pressure ratio,pile acceleration,pile bending moment and pile top horizontal displacement of six pile foundations with large diameter and variable section are studied when the thicknesses of the liquefied soil layer are 30,40 and 50 cm.The results show that the acceleration and bending moment of six-pile foundation with large diameter and variable section change abruptly at the interface between variable section and soil layer under different thicknesses of saturated sand layer.Under the same soil thickness,with an increase of ground motion intensity from 0.15g to 0.45g,the pore pressure ratio of saturated sand,pile acceleration,horizontal displacement of pile top and pile bending moment all increase.Under the ground motion intensity of 0.15g,the stable value of pore pressure ratio of the six-pile foundation decreases with an increase of saturated sand layer thickness,but the horizontal displacement of pile top,pile acceleration and peak bending moment of the six-pile foundation gradually increase and increase.It is suggested that in the design of large diameter variable section pile foundation in liquefaction site,special consideration should be given to the dynamic response difference of six large diameter variable section pile foundation under different thickness of liquefied soil layer,and pay attention to the flexural performance of the interface between the variable section and soil layer,so as to ensure the seismic performance of the six pile foundation.

关 键 词：桩基 大直径变截面六桩 振动台试验 动力响应 饱和砂土 

分 类 号：TU473.1[建筑科学—结构工程] TU435[建筑科学—土工工程]