Real-time monitoring of unauthorized working activities above the subway tunnel is an intractable issue. Illegal drill rig working is one of the most threatening way of intrusion. Nowadays, the distributed optic fiber sensing technology promises to provide a viable means for the long distance monitoring in the complex working conditions. To tackle the difficult problem of drill rig intrusion, we use the ultra-weak fiber Bragg grating vibration sensing array to acquire the vibration signals, and propose a real-time monitoring method based on the detection of the vibration due to the running engine. The alarm strategy identifies the engine vibration according to the narrow frequency band feature of the signal. Due to the continuity of engine working and randomness of noise interferences, the statistical analysis is adopted on the identification results. The intrusion location is achieved by the proposed method. We validate the proposed monitoring method in the field trials.

实时监控地铁隧道上方未经授权的工作活动是一个棘手的问题。非法钻机作业是最具威胁性的入侵方式之一。如今，分布式光纤传感技术有望为复杂工况下的远距离监测提供一种可行的手段。针对钻机侵入这一难题，我们采用超弱光纤布拉格光栅振动传感阵列来获取振动信号，并提出了一种基于发动机运行振动检测的实时监测方法。报警策略根据信号的窄频带特征识别发动机振动。由于发动机工作的连续性和噪声干扰的随机性，对识别结果进行统计分析。入侵定位是通过所提出的方法实现的。我们在现场试验中验证了所提出的监测方法。