桩-土-上部结构动力相互作用振动台试验研究  

Shaking table test study on seismic-soil-pile-superstructure-interaction

作　　者：汪刚 景立平[1,2] 李嘉瑞 何斌 尹志勇 WANG Gang;JING Liping;LIJiarui;HE Bin;YIN Zhiyong(Institute of Engineering Mechanics,China Earthquake Administration,Harbin,Heilongjiang 150080,China;Institute of Disaster Prevention Science and Technology,Sanhe,Hebei 065201,China)

机构地区：[1]中国地震局工程力学研究所,黑龙江哈尔滨150080 [2]防灾科技学院地质工程学院,河北三河065201

出　　处：《岩石力学与工程学报》2021年第S02期3414-3424,共11页Chinese Journal of Rock Mechanics and Engineering

基　　金：中国地震局工程力学研究所基本科研业务费专项资助项目(2019B10);国家科技重大专项资助项目(2018ZX06902016)

摘　　要：为了深入分析地震荷载作用下桩-土-上部结构动力相互作用(SSPSI)中运动相互作用(KI)与惯性相互作用(II)的特征,设计了端承单桩-中硬黏土-上部结构(质量可变)试验模型,并利用振动台试验进行了相关研究。首先讨论了不同工况下桩基承台的运动规律,然后通过对比加速度峰值放大系数来定性说明承台处运动相互作用和惯性相互作用的贡献,最后通过定义并计算相干函数比R来进一步定量说明了不同工况下运动相互作用和惯性相互作用的贡献大小。分析结果表明:各工况下承台主要沿振动方向进行水平运动,承台转角对于桩头弯矩的贡献非常小,可以忽略不计:在没有上部结构或上部结构质量较小(37.5%R_(a),R_(a)为基桩竖向承载能力特征值)且地震动幅值较小(0.1 g及以下)时,运动相互作用占优,而当上部结构质量较小(37.5%R_(a)及以下)但地震动幅值较大(0.2 g),或者上部结构质量较大(75%R,及以上)时,惯性相互作用占优。因此当上部结构较重时,惯性相互作用对桩基水平承载力具有较大影响,在对这类结构的桩基进行抗震设计时应注意考虑上部结构振动特性的影响。In order to deeply analyze the characteristics of kinematic interaction(KI)and inertial interaction(II)in seismic-soil-pile-superstructure-interaction(SSPSI),a test model with end-bearing single pile,medium-hard clayand superstructure(variable mass)is designed and studied by shaking table test.Firstly,the motion of pile cap under different test conditions is discussed,and then the contribution of kinematic interaction and inertial interaction at the upper surface of pile cap is qualitatively explained by comparing the amplification coefficient of peak acceleration.Finally,the contribution of kinematic interaction and inertial interaction under different test conditions is further explained quantitatively by defining and calculating the coherence function ratio R.The analysis results show that the pile cap mainly moves horizontally along the vibration direction,and the contribution of rotation of the pile cap to the bending moment of the pile head is very small,which can be ignored.When there is no superstructure,or the weight of superstructure is small(37.5%R_(a)and below,R is the characteristic value of pile vertical bearing capacity)whereas the amplitude of ground motion is small(0.1 g and below),the kinematic interaction is dominant.When the weight of superstructure is small(37.5%R_(a)and below),but the amplitude of ground motion is large(0.2 g),or the weight of superstructure is large(75%/R_(a)and above),the inertial interaction is dominant.Therefore,when the superstructure in SSPSI is heavy,the inertial interaction has a great impact on the horizontal bearing capacity of pile foundation,and attention should be paid to the influence of vibration characteristics of superstructure in the seismic design of pile foundation for this kind of structure.

关 键 词：桩基础 振动台试验 SSPSI 频率响应函数 相干函数 

分 类 号：P473[天文地球—大气科学及气象学]