高速列车荷载作用下高架桥和地基振动分析

提出了一种准解析方法来分析高速列车运行荷载作用下高架桥的动力响应。着重考虑了桥梁和地基的动力相互作用。通过动力子结构方法把研究对象分成两部分，一个是列车荷载作用下三维高架桥的有限元振动模型，另一个是基于傅里叶级数展开的轴对称群桩基础与周围分层地基动力相互作用模型，两者通过桩基承台节点处的连续条件进行结合。用薄层单元构建了应力波的透射边界条件来模拟远场地基对近场有限元区域的影响作用。用阻抗函数来表示群桩基础对上部桥梁结构的支撑作用。通过数值计算考察了软弱地基上新干线高架桥在高速列车荷载作用下的振动特性，分析了列车轮轴荷重，运行速度和群桩基础等因素对高架桥振动的影响；本分析模型和方法在计算上具有很高的效率。同时根据计算结果与现场实测的对比说明了本方法的可靠性。

Analysis of viaduct-ground vibrations due to high-speed train moving loads

For viaduct structures, the vibrations induced by high-speed train passages are studied by taking into account soilpile foundation-vladuct interaction effects. The dynamic substructure method is applied to solve the structure governing equations in the frequency domain. A viaduct structure,which includes rail, track and pier supports is discretized by three-dimensional beam-column elements. Pile foundation and surrounding soil in the near field are modeled by three-dimensional axisymmetric finite elements in a semi-analytical way, while the ground in far field is treated as a layered isotropic media and a transmitting boundary is constructed through the thin layer method. An illustrative case study on Japan Shinkansen viaduct is conducted to investigate the controlling parameters of viaduct dynamic behaviors under train moving loads, which include train speed, wheel-axel weights and viaduct geometry. The numerical computation results have been verified via a comparison with the field measurements of the ground responses.