摘要
以新建铁路宁波至舟山铁路桃夭门公铁两用跨海大桥为研究对象,在分析墩位水文地质特征基础上,运用仿真分析的手段建立大跨度跨海桥梁桩基地震分析模型,研究桥梁桩基动力特性及时变地震响应。结果表明:长期冲刷对桥梁结构的动力特性有显著影响,桥梁模型的自振周期与基础冲刷深度呈现正相关关系,且在前3阶模态振型和第8阶的自振周期增加明显;在相同冲刷深度条件下,桩顶位置变形较大,随着深度的增加,桩基地震变形呈非线性迅速衰减并趋于零;随着冲刷深度的增加,最大冲刷线以上桩基的位移不断增加,最大冲刷线以下桩基的位移增幅较小;桥梁桩基损伤超越概率与基础冲刷深度(冲刷时间)呈现正相关关系;在同一工况下,随着损伤状态从轻微损伤、中等损伤、严重损伤和完全损伤变化,桥梁桩基的损伤超越概率逐步减小;桥梁桩基纵桥向发生严重损伤的概率比横桥向大,纵桥向和横桥向发生完全损伤的概率大致相同。
The Taoyaomen Rail-cum-Road Sea Crossing Bridge on newly-built Ningbo-Zhoushan Railway is taken as the research object.Based on the analysis of the hydrogeological characteristics of the pier location,a seismic analysis model for the pile foundation of a large-span sea crossing bridge was established using simulation analysis methods to study the dynamic characteristics and time-varying seismic response of the bridge pile foundation.The results indicate that long-term erosion has a significant impact on the dynamic characteristics of bridge structures.The natural vibration period of the bridge model is positively correlated with the depth of foundation erosion,and there is a significant increase in the first three modal modes and the eighth natural vibration period;under the same scouring depth conditions,the deformation at the top of the pile is relatively large.As the depth increases,the seismic deformation of the pile foundation shows a nonlinear and rapid decay and tends to zero;as the depth of erosion increases,the displacement of the pile foundation above the maximum erosion line continues to increase,while the increase in displacement of the pile foundation below the maximum erosion line is relatively small;the probability of bridge pile foundation damage exceeding the limit is positively correlated with the depth of foundation erosion(erosion time);under the same working condition,as the damage state changes from minor damage,moderate damage,severe damage,and complete damage,the probability of damage exceeding the bridge pile foundation gradually decreases;the probability of serious damage to the bridge pile foundation in the longitudinal is higher than that of the transverse direction,while the probability of complete damage in the longitudinal and transverse directions is roughly the same.
作者
沙仁智
SHA Renzhi(China Railway Construction Bridge Engineering Bureau Group Co.Ltd.,Tianjin 300450,China)
出处
《铁道建筑技术》
2023年第9期90-93,118,共5页
Railway Construction Technology
基金
中国铁建股份有限公司科技研发计划项目(2022-B05)。
关键词
长期冲刷
桃夭门公铁两用大桥
时变抗震性能
跨海桥梁
桩基
long term erosion
Taoyaomen Rail-cum-Road Bridge
time-varying seismic performance
sea crossing bridge
pile foundation
