高速铁路桥梁及场地土交通振动分析

his study was a critical evaluation of the analysis method for ground vibration induced by passing trains on bridge structures. A variety of finite elements and meshes were employed, including those representing bridge superstructures, bridge foundations, soils, and moving trains, where each train car was described by 27 degrees of freedom. Soil foundation data were measured on-site at the Beijing-Shanghai high-speed railway, and as part of the soil modeling, viscous-spring artificial boundary elements were employed to avoid fictitious wave reflections. Contact between train-car wheels and the underlying rails was simulated using 3D dynamic contact elements, which were based on a Coulomb-contact algorithm. Through the simulations, ground vibrations induced by vehicle-bridge coupling were calculated. The results show that the vibration of the coupled vehicle-bridge system is significantly influenced by nearby pier and pile foundations. Furthermore, vertical vibration levels were found to attenuate with increasing distance to foundation, whereas attenuation is not as clearly pronounced with horizontal vibrations. The high frequency components in ground vibration attenuate more rapidly than low frequency components, and therefore, remote field vibrations contain dominant low frequency components. Ground vibration levels do not directly correlate with vehicle speed, where the ground vibrations are largely affected by any preceding superstructure vibrations.