【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。更多还原

【Abstract】 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.更多还原