基于膜片F-P干涉的高灵敏光纤地铁隧道异常振动探测技术研究

Research on High Sensitivity Fiber Abnormal Vibration Detection Technology in Subway Tunnels Based on Membrane F-P Interference

摘要:

对地铁隧道异常振动进行安全检测和预警是保障地铁安全运行的重要保障。本文针对地铁隧道异常振动和外界入侵应用场景研发了膜片F-P光纤干涉式高灵敏度次声波传感探头及准分布式光纤地铁隧道异常振动探测系统。该系统通过在地铁隧道的上行线和下行线不同位置布设多个高灵敏的光纤声波传感探头，用于探测隧道内部或隧道上方机械设备施工时产生的次声波信号，由传输光纤光缆将信号传输至系统主机，经系统主机处理与分析，对异常振动信息进行报警，进而实现对地铁隧道异常振动的全天候、全时段实时检测。研发的次声波传感器的频率响应范围为0.1~100 Hz；灵敏度为1047 mV/Pa（@ 0.1Hz）~5445 mV/Pa（@ 12.5Hz）。在广州地铁对探测系统进行了应用验证测试，测试结果表明该系统可以准确识别列车激励导致的隧道结构受迫振动信号，并实时做出反馈。

Abstract:

Safe detection and early warning of abnormal vibrations in subway tunnels is an important guarantee for ensuring the safe operation of the subway. In this paper, a high-sensitivity membrane F-P fiber interferometric sensor and the sensor based quasi-distributed fiber optic detection system for abnormal vibration and external intrusion in subway tunnels are developed and demonstrated. The system deploys multiple highly sensitive fiber optic sound wave sensing sensors at different positions on the up and down lines of the subway tunnel to detect the infrasound wave signals generated during the construction of mechanical equipment inside or above the tunnel. The sensing signals are transmitted to the system host through the transmission fiber cable, which processes and analyzes the abnormal vibration information to give an alarm, thereby achieving real-time detection of abnormal vibration in the subway tunnel with all-weather and all time. The frequency response and sensitivity range of the developed infrasound wave sensor is 0.1~100 Hz and 1047 mV/Pa (@ 0.1Hz) to 5445 mV/Pa (@ 12.5Hz), repectively. The application verification test of the detection system was carried out at Shahe Station on Guangzhou Metro Line 6, and the test results showed that the system can accurately identify the forced vibration signals of tunnel structures caused by train excitation and provide real-time feedback.