桩-承台不同连接方式下的桩基-结构动力响应离心机振动台试验研究  

Centrifuge shaking table tests on dynamic response of pile-structure with different pile-cap connections

作　　者：郑刚[1,2] 张文彬 赵继辉[1,2] 周海祚 ZHENG Gang;ZHANG Wenbin;ZHAO Jihuil;ZHOU Haizuol(School of Civil Engineering,Tianjin University,Tianjin 300350,China;Key Laboratory of Coast Civil Structure Safety,Tianjin University,Ministry of Education,Tianjin 300350,China)

机构地区：[1]天津大学建筑工程学院,天津300350 [2]天津大学滨海土木工程结构与安全教育部重点实验室,天津300350

出　　处：《建筑结构学报》2025年第1期204-211,222,共9页Journal of Building Structures

基　　金：国家自然科学基金项目(52078335,52322809,52078337)。

摘　　要：桩与承台之间通常采用刚性连接形式,然而在地震作用下刚性连接附近易发生应力集中,导致桩基发生破坏。同时,桩基是隐蔽工程,破坏后难以进行检测与修复。因此,对桩基-结构动力进行响应离心机振动台试验,研究刚性、半刚性和垫层三种桩-承台连接形式对上部结构与桩基的动力响应特征及受力分布规律的影响,并开展浅基础形式作为变形的对比组研究。结果表明:地震作用下,相较于桩-承台刚性连接,半刚性连接和垫层连接方式均可有效降低上部结构动力加速度响应;刚性与半刚性连接形式下,虽会出现较大的上部结构净位移,但显著限制基础转动与平动位移;垫层连接具有隔振作用,可显著减少上部结构净位移,然而由于承台与桩体无抗拉连接,基础的转动与平动位移显著;加速度幅值较大时(apg=0.3g)基础转动位移增量明显,易发生基础与地基脱离的现象;在桩体受力性能方面,桩-承台半刚性连接和垫层连接通过减弱上部的惯性力,可分别降低桩顶弯矩和桩身弯矩,对防止桩基发生弯曲破坏起到有益作用。The connections between the piles and the caps are typically designed as rigid connections.However,under seismic loading,stress concentrations are likely to occur near the rigid connections,which can lead to damage in the pile foundation.Additionally,since pile foundations are often concealed,detecting and repairing damage after it occurs can be quite challenging.Therefore,a series of dynamic response tests using a centrifuge shaking table were conducted to investigate the effects of three types of pile-cap connection forms,the rigid,the semi-rigid,and the cushion connection,on the dynamic response characteristics and force distribution patterns of the superstructure and pile foundation.A shallow foundation condition was also studied as a reference group for deformation analysis.The results indicate that,under seismic loading,both semi-rigid and cushion connection methods can effectively reduce the dynamic acceleration response of the superstructure compared to rigid connections.While significant net displacement of the superstructure occurs under both rigid and semi-rigid connections,these configurations notably limit the rotational and translational displacements of the foundation.The cushion connection exhibits vibration isolation properties,significantly reducing the net displacement of the superstructure.However,due to the lack of tensile connection between the cap and the piles,the rotational and translational displacements of the foundation are significant.When the acceleration amplitude is large(a_(pg)=0.3g),the increase in rotational displacement of the foundation is evident,raising the risk of separation between the foundation and the ground.In terms of the loadbearing performance of the piles,the semi-rigid and cushion connections help to mitigate the inertial forces acting on the superstructure,thereby reducing the bending moments at the pile tops and along the pile shafts.This reduction plays a beneficial role in preventing bending failures of the pile foundation.

关 键 词：桩-承台系统 刚性连接 半刚性连接 垫层连接 离心机振动台试验 动力响应 

分 类 号：TU753[建筑科学—建筑技术科学]