【摘要】 以一座大跨悬索桥中塔沉井基础为工程背景,采用"m"法建立了沉井-土动力相互作用计算模型,研究了沉井-土动力相互作用对全桥结构地震反应的影响,并对其影响机理进行了探讨,最后分析了河床冲刷深度的变化对结构地震反应的影响。研究结果表明,沉井-土动力相互作用对边塔的地震反应影响较小,但会增大中塔的地震反应;考虑沉井-土动力相互作用时,在与基础的自振周期相近时,结构的地震反应表现出显著的共振效应,使得结构地震反应增大;河床冲刷深度变化对结构的地震反应有很大的影响,随着冲刷深度的增加,桥梁结构的地震反应并不是单调变化,而可能出现一个峰值。更多还原

【Abstract】 In combination with a caisson foundation of mid-tower of a long span suspension bridge,the analytical model is established to consider the caisson-soil dynamic interaction using "m" analysis method.The effect of caisson-soil dynamic interaction on seismic response for the bridge is studied and the effect reason is also discussed.And the effects of scouring depth on the seismic response of structure are also analyzed.The results indicate that caisson-soil dynamic interaction has significant effect on the seismic response of the mid-tower,but has minor effect on the seismic response of the side-tower.The bridge displays the remarkable resonance vibration phenomenon as its dynamic period is close with the dynamic period of caisson foundation and the seismic demand of the bridge is increased obviously considering caisson-soil dynamic interaction.The scouring depth has a significant effect on the seismic response of the bridge,and as the scouring depth increases,the seismic response of the bridge does not monotonously vary,and there possibly is a peak value.更多还原