This paper investigates the attenuation characteristics of far-field environmental vibrations induced by the high-speed maglev train, especially the attenuation with depth. Field tests are carried out to measure the train-induced ground vibrations at different distances and soil depths. The vibration amplitude generally decreases as the distance increases according to Bornitz's formula. However, for the vibration along depth, there is an amplification zone where the vibration amplitude is much larger than the analytical prediction in a homogeneous soil. Numerical simulation using finite element method is also adopted to analyze the attenuation of vibrations and the results are consistent with the field measurements. Moreover, analytical transfer-matrix method is used to calculate the dispersion curve of Rayleigh wave in layered soils, and an analytical model is proposed to predict the vibration attenuation with depth. The vibration attenuation curve along depth obtained by the proposed model shows good agreements with the field measurement and numerical simulation. It reveals that the amplification of vibration at certain depths below the ground is attributed to the resonance of Rayleigh wave in layered soils.

本文研究了高速磁悬浮列车引起的远场环境振动的衰减特性，特别是深度衰减。进行了现场测试，以测量列车在不同距离和土壤深度下引起的地面振动。根据Bornitz公式，振动幅度通常随着距离的增加而减小。但是，对于沿深度的振动，存在一个放大区域，该区域的振幅比均匀土壤中的分析预测值大得多。还采用有限元数值模拟方法对振动衰减进行了分析，其结果与现场测量结果吻合。此外，采用解析传递矩阵法计算层状土中瑞利波的频散曲线，提出了解析模型来预测随深度的振动衰减。所建立的模型沿深度方向的振动衰减曲线与现场测量和数值模拟吻合良好。结果表明，地下某些深度处的振动放大是由于层状土壤中的瑞利波共振引起的。