Elastic Full Waveform Inversion Based on the High-Speed Rail Seismic Source

With the establishment of a widely distributed and dense high-speed rail network, high-speed rail will be spread all over China in the near future. Research shows that high-speed rail seismic waves contain rich geological structure information. When the high-speed rail passage over the viaduct, the pile foundations will be subjected to various forces, and through the interactions with the soil and rock layers, the high-speed rail seismic waves will be excited and propagated. In this paper, based on the investigation of the excitation mechanism of the high-speed rail seismic waves, we derive the high-speed rail seismic source time function, which is a delay superposition of a series of discrete point sources. To make full use of the high-speed rail seismic signals and explore the rich geological structure information, we investigate the elastic full waveform inversion method based on the high-speed rail seismic source. Then, we perform numerical experiments for the simple model and the complex model containing anomalous bodies. The results of numerical experiments show that the inversion results basically converge, and the anomalous bodies can be reconstructed effectively. Therefore, studying the excitation mechanism of high-speed rail seismic waves and combining them with the elastic full waveform inversion method is feasible to realize the velocity inversion in the area nearby the high-speed rail network.