The high-precision distributed acquisition of high-speed rail seismic waves were achieved using the High-Definition Distributed Acoustic Sensing (HD-DAS) system. The sensor unit used simple communication optical cable to achieve good monitoring effects at low cost, and could be easily deployed according to actual environmental conditions, greatly improving the efficiency of field observation work. By using multiple parallel optical cables, noise could be effectively suppressed and the signal-to-noise ratio of high-speed rail seismic signals can be improved. Data analysis and processing were performed on seismic signals collected by HD-DAS from high-speed rail. The analysis revealed that the signals display discrete spectral characteristics. Further analysis was conducted on the attenuation law of seismic wave signals, and the transmission speed of seismic waves near the surface was obtained through the frequency-wavenumber spectrum. This indicated that the high-speed rail seismic wave signals acquired through optical fiber could be used to detect underground structures and monitor changes in the medium’s state, thereby enhancing the safety of high-speed rail operations.

利用高清分布式光纤声波传感(HD-DAS)系统, 进行高铁地震波场的高精度分布式采集。传感单元采用结构简单、成本低廉的通信光缆即可实现很好的监测效果, 可以方便地根据实际环境进行布设, 大大提高了野外观测的效率。采用多光缆并行布放, 信号叠加后可有效地抑制噪声, 提高高铁地震信号的信噪比。对HD-DAS系统采集到的高铁地震信号进行数据分析, 发现高铁地震信号呈现分立谱特性。通过分析地震波信号的衰减规律, 并通过频率–波数谱得到地震波在近地表的传输速度, 表明光纤采集的高铁地震波信号可用于探测地下结构, 并进一步实现对介质状态变化的监测, 从而保障高铁的运行安全。