LAUSR

The pile-supported subgrade has been widely used in high-speed railway construction in China. To investigate the ground vibrations of such composite foundation subjected to moving loads induced by high-speed trains (HSTs), three-dimensional (3D) finite element method (FEM) models involving the pile, pile cap and cushion are established. Validation of the proposed model is conducted through comparison of model predictions with the field measurements. On this basis, ground vibrations generated by HSTs under different train speeds as well as the ground vibration attenuation with the distance away from the track centerline are investigated. In addition, the effects of piles and pile elastic modulus on ground vibrations are well studied. Results show that the pile-reinforcement of the subgrade could significantly contribute to the reduction of ground vibrations. In particular, the increase of elastic modulus of pile could lead to consistent reduction of ground vibrations. However, when the pile elastic modulus is beyond 10 GPa, this benefit of pile-reinforcement on vibration isolation can hardly be increased further. 桩-土复合路基广泛应用于我国高速铁路工程建设。为研究高速列车运行引起的桩-土复合路基 地面振动,本文建立了包含桩体、桩帽和垫层在内的复合路基3 维有限元模型,通过与现场实测数据 对比验证了模型的有效性。在此基础上,分析了不同车速高铁荷载作用下地面振动及其与轨道中心间 距的衰减规律。此外,还研究了桩基及桩体弹性模量对地面振动的影响。研究表明,复合路基中桩体 的加固能有效减小地面振动;另外,减振效果随着桩体弹性模量的增加而增大。然而,当桩体弹性模 量超过10 GPa 时,进一步增大弹性模量就不再明显增加地面振动的减振效果。