层状地基中桥梁柱墩基础地震响应振动台试验研究  

Shaking Table Test for Evaluating Seismic Response Characteristics of Columned Bridge Foundation in Layered Stratum

作　　者：邓志华 曾磊 林聪煜 邹力 刘齐建[2] DENG Zhi-hua;ZENG Lei;LIN Cong-yu;ZOU Li;LIU Qi-jian(Guangzhou Expressway Co.,Ltd.,Guangzhou 510290,China;College of Civil Engineering,Hunan University,Changsha 410082,China;China Railway Bridge Science Research Institute,Ltd.,Wuhan 430034,China)

机构地区：[1]广州市高速公路有限公司,广东广州510290 [2]湖南大学土木工程学院,湖南长沙410082 [3]中铁大桥科学研究院有限公司,湖北武汉430034

出　　处：《桥梁建设》2022年第6期50-57,共8页Bridge Construction

基　　金：国家自然科学基金项目(51878265,52178331)。

摘　　要：为确保层状地基中桥梁柱墩基础在地震作用下的安全,对层状地基中桥梁独柱墩和双柱墩的横、顺桥向地震响应进行试验研究。以南沙至中山高速公路沙仔滘特大桥为背景,通过振动台试验,分析不同超越概率地震波激励下桥梁柱墩基础自振频率、墩顶位移和桩身弯矩。结果表明:顺桥向地震激励下独柱墩和双柱墩第一阶自振频率接近,且对小于5 Hz的低频地震波有放大效应;横桥向地震激励下双柱墩第一阶自振频率大于顺桥向地震激励。对于独柱墩,地震输入结束后墩顶位移随时间衰减,桩身弯矩在桩顶和软硬土层交界面处出现峰值,且桩顶弯矩远大于软硬土层交界面处桩身弯矩,大震作用时更为明显。对于双柱墩,顺桥向地震激励下墩顶位移和桩身弯矩远大于横桥向地震激励,桩身弯矩规律与独柱墩类似;横桥向地震激励下,桩身弯矩呈“剪刀形”变化,墩顶、墩底、桩顶和软硬土层交界面处均出现弯矩峰值,墩底和桩顶位置产生不平衡弯矩。A shaking table test was conducted to examine the transverse and longitudinal seismic response characteristics of the single-column and double-column piers in the layered stratum,and the safety of the columned bridge foundation in the layered stratum was analyzed.The Shazaijiao Bridge of Nansha-Zhongshan Expressway is used as a case.The natural frequency of the bridge and the pier-top displacement and pile-shaft bending moment of the columned foundation under the excitation of earthquake waves of different exceedance probability were analyzed.The results show that under the excitation of longitudinal earthquake waves,the first-mode natural frequencies of the single-column and double-column piers are close,and the amplification effect is significant when the frequency is less than 5 Hz.While under the excitation of transverse earthquake waves,the first-mode natural frequency of the double-column pier is greater than that of the longitudinal earthquake waves.For the single-column pier,the pier-top deformation decays with time after the input of earthquake waves,and the peaks of the pile-shaft bending moment appears in the pier top and the soft-solid interface of soil layers,and the pier-top bending moment is far greater than that of the pile shaft at the soft-solid interface of soil layers,and the effect is more obvious under major earthquakes.For the double-column pier,the pier-top displacement and pile-shaft bending moment under the excitation of longitudinal earthquakes are far greater than that of the excitation of transverse earthquakes,the characteristics of the pile-shaft bending moment is similar to that of the single-column pier.Under the excitation of transverse earthquakes,the pile-shaft bending moment shows sign of scissors-shape variation.The bending moment peaks appear in the pier top,pier base,pile top and soft-solid interface of soil layers,and unbalanced bending moment is observed in the pier base and pile top.

关 键 词：桥梁柱墩 桩基础 层状地基 地震响应 自振频率 墩顶位移 桩身弯矩 振动台试验 

分 类 号：U443.22[建筑科学—桥梁与隧道工程] U442.55[交通运输工程—道路与铁道工程]