The ground vibration generated by running high-speed trains (HSTs) can excite seismic wavefields with high stability and good repeatability. When the seismic waves generated by the HST source propagate in the subsurface medium, information about the geological structure of the subsurface is embedded in the wavefields, which can be used for imaging and inversion. To make better use of the HST seismic data, it is necessary to focus on the propagation characteristic and carry out a forward modeling study of the seismic wavefield generated by the HST. Since the seismic waves generated by running HST propagate through 3-D space in practice, it is vital to explore the forward modeling of the HST seismic data in 3-D space, which can obtain more accurate simulation results of the seismic wavefield and helps for a better understanding of the wavefield characteristic of the HST seismic data. In this work, we conduct full-wave forward modeling of the wavefield excited by HSTs running on viaducts in 3-D space. The moving combination source function of the HST seismic data is provided. We use the 3-D isotropic elastic wave equation with constant density in this work and employ the free surface boundary condition to ensure the simulation for both body waves and surface waves. The 3-D finite-difference method with a staggered-grid technique is applied for the forward modeling. By comparing the simulated data with the real HST seismic data, we found that there is a good similarity between them. The 3-D forward modeling of the HST seismic data in this article lays the foundation for wavefield characterization and subsurface medium inversion in the future.

中文翻译：

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3维空间中高速列车诱发地震波场的正演模拟


高速列车运行产生的地面振动可以激发出稳定性高、重复性好的地震波场。当HST震源产生的地震波在地下介质中传播时，地下地质结构的信息就嵌入到波场中，可用于成像和反演。为了更好地利用HST地震资料，需要关注其传播特性，对HST产生的地震波场进行正演模拟研究。由于实际运行HST产生的地震波是通过3维空间传播的，因此探索3维空间中HST地震数据的正演建模至关重要，这样可以获得更准确的地震波场模拟结果，有助于更好地了解HST地震数据的波场特征。在这项工作中，我们对 3D 空间高架桥上运行的 HST 激发的波场进行全波正演建模。提供HST地震数据的移动组合震源功能。在这项工作中，我们使用具有恒定密度的三维各向同性弹性波方程，并采用自由表面边界条件来确保体波和表面波的模拟。采用交错网格技术的 3-D 有限差分法用于正演建模。通过将模拟数据与真实的HST地震数据进行比较，我们发现它们之间有很好的相似性。本文对HST地震数据的3D正演模拟为未来波场表征和地下介质反演奠定了基础。