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地震反应的有效估计是液化场地桥梁结构设计、加固改造的必要环节,但通过数值模拟手段获得的结果易受模型参数变化的影响。为探究影响液化场地桥梁结构地震反应的控制性参数,该文首先建立了某离心机试验的场地-结构整体有限元模型,通过数值分析与试验结果的对比验证了数值方法的可靠性;然后,建立了上覆粘土层-松砂层-密砂层的典型倾斜液化场地-桩柱式桥梁结构有限元模型,采用龙卷风图和一次二阶矩方法,以场地和结构的主要物理性质为分析参数,进行场地、结构地震反应的敏感性分析。结果表明:场地、结构的地震反应与各分析参数大体上呈线性或低非线性的变化关系;在所研究的参数中,液化松砂层的内摩擦角、土层倾角和地震峰值加速度为控制性参数,而密砂层各参数和钢筋、混凝土强度参数的敏感性均很低。研究结果可对液化场地桥梁结构地震反应的准确估算,振动台、离心机模型试验的工况优化提供科学参考。
The effective estimation of seismic response is an essential part of the design, reinforcement and reconstruction of bridge structures in liquefied sites. However, the results obtained through numerical simulation are easily affected by the changes of model parameters. In order to explore the control parameters affecting the seismic response of bridge structures in liquefied sites, this paper first established a site-structure finite element model of a centrifuge test. The numerical results are compared with the numerical results to verify the reliability of the numerical method. The finite element model of typical inclined liquefied ground-pile bridge structure with overlying clay layer-loose sand layer-sand layer was established. The tornado pattern and first order second moment method were used to analyze the main physical properties of site and structure , The sensitivity analysis of site and structure earthquake response. The results show that the seismic responses of the site and the structure are generally linear or nonlinearly nonlinear with respect to the analysis parameters. In the studied parameters, the internal friction angle, the dip of the soil layer and the peak acceleration of the earth are controlled The parameters of the sand layer and the sensitivity of the strength parameters of steel and concrete are very low. The research results can provide a scientific reference for the accurate estimation of the seismic response of bridge structures in liquefied sites and the optimization of the working conditions of shaking table and centrifuge model tests.