液化场地桩-土-桥梁结构地震相互作用简化分析方法

液化场地桩-土-桥梁结构地震相互作用分析属于桩基桥梁抗震设计中的一个关键科学问题，而目前尚缺乏合理的简化分析方法。鉴于此，直接针对振动台试验，基于Penzien模型，建立了液化场地桩-土-桥梁结构地震相互作用的数值分析模型与相应的简化分析方法。通过振动台试验验证了数值建模途径与简化计算分析方法的正确性，可用于液化场地桩基桥梁结构地震反应的分析，并且特别考虑砂层中孔压升高引起的砂土承载力衰减效应，推荐了计算参数的合理选取方法；据此进行了桩径、桩土初始模量比、砂土内摩擦角、上部桥梁结构质量等重要参数对液化场地桩-土地震相互作用影响的敏感性分析。研究表明：在液化场地条件下，随桩径和桩土初始模量比的增大，桩的峰值加速度、峰值位移减小，而桩的峰值弯矩则增大；随砂土内摩擦角增大，桩的峰值加速度、峰值弯矩、峰值应力均增大，而桩的峰值位移则减小；随上部结构配重增大，桩的峰值位移、峰值弯矩均增大。

Simplified Analysis Method for Seismic Pile-Soil-Bridge Structure Interaction in Liquefying Ground

The seismic pile-soil-bridge structure interaction analysis in liquefying ground is a critical problem for seismic design of pile-supported bridge. However, there is no rational numerical model and simplified analysis method to deal with this problem. A numerical model and a simplified method were developed based on Penzien model according to vibrating table test to simulate seismic pile-soil-bridge structure interaction.The simplified method was verified by the computed results for further study.The parameters in simplified method was recommended, which particularly considered the effect of pore pressure on the bearing capacity of sand.The parameter analysis about pile diameters, the initial modulus ratios between pile and soil, the internal angle of sand and the mass of superstructure, was conducted to study the effect on seismic pile-soil interaction. Under the condition of liquefying ground, the recorded and computed results showed that the peak acceleration and the peak displacement of pile decreased and the peak moment on the pile increased as pile diameters and initial modulus ratios increased; the peak acceleration, the peak moment and the peak stress of pile increased when the internal friction angle of sand increased; the peak displacement and the peak moment of pile increased with the increasing mass of superstructure.