减低交通荷载引起地面振动的三维数值分析

3D Numerical Analysis for Traffic Reduction Induced Ground Vibration

针对高速铁路和高等级公路的运行产生振动波可能带来严重的噪音和地面振动等环境问题,运用LS-DYNA软件,选用更适合岩土介质的弹塑性模型,对高速列车作用下地面振动及连续墙挡板的防护能力进行三维数值模拟分析。研究了5～20 Hz荷载下混凝土桩组成的不同尺寸挡板的减振效果,并与日本某现场试验结果比较。结果表明,尽管无填充壕沟的防护效果最佳,但钢筋混凝土桩墙更具可操作性,稳定性,且混凝土桩减振挡板可以显著减低地面的振动加速度幅值,与波长有关。挡板长度和深度直接影响混凝土减振挡板的防护效果和防护范围,挡板深度对防护效果的影响更为明显,挡板宽度的尺寸主要影响防护范围。

The operations high speed railways and high grade roads may cause some environmental problems such as serious noises and drastic ground vibration. Focusing on the problem, high speed train induced ground vibration and the isolation of a continuous vibration barrier on ground vibration were analyzed with a 3D numerical simulation through LS-DYNA software and elastoplastic model which describes soil medium more reasonable. Particularly, the reducing vibration effect of the reinforced concrete pile barriers with different dimensions subjected to dynamic loads of 5 -20 Hz was analyzed, and numerical simulations were compared with Japanese in-situ test results. The results indicate that （ 1 ） although the protection effect of open trench is the best, the operation and stability of reinforced concrete pile wall are much stronger, and the acceleration magnitude of ground vibration can be reduced remarkably by the PC pile wall, which has a relationship with wave length; （2） barrier length and depth can determine the protection effect and zone of PC pile wall, the influence of barrier depth on the protection effect is much more obvious, while barrier length mainly affects the protection zone.