开展了光纤预警系统在实时监控振动信号时受到土壤温度影响的理论分析和实验研究。以基于后向瑞利散射的分布式光纤传感系统为基础, 土壤振动分析采用弹性半空间理论, 并与光纤传感理论相结合, 解释了温度对光纤预警系统中土壤振动信号的影响, 建立并分析了理论模型。通过对1.2km光纤预警系统的现场实验, 采集了在温度改变时土壤振动信号的变化。实验表明, 土壤振动信号的峰值光功率随温度上升增大, 说明了光纤预警系统中的振动信号会受土壤环境的影响。

The theoretical analysis and experimental study of the influence of soil temperature on vibration signal is carried out in the optical fiber warning system based on Rayleigh backscattering.Elastic half-space theory and optical fiber sensing theory is applied in the analysis of soil vibration. The influence of soil temperature on vibration signal is explained and then the theoretical model is established and analyzed. In order to demonstrate the model, an experimental measurement with 5km-long single-mode sensing fiber is performed. The experimental results show that the peak optical power of soil vibration signal increases with the rise of the soil temperature.