基于分布式光纤技术的煤矿巷道顶板监测系统

当前巷道顶板变形监测方式为基于井下工业环网的在线实时监测,采用电子式和光纤光栅式的位移传感器并以无线方式连接,存在有较多监测盲点、误差较大、依靠连续供电等问题。针对上述问题,设计了一种基于分布式光纤技术的煤矿巷道顶板监测系统。该系统以布里渊光时域反射计(BOTDR)作为数据采集和分析的核心监测工具,采用5 mm钢绞线光纤作为感测光纤,以锚杆、锚索为固定点布设光缆,通过顶板光纤的应变变化来监测顶板变形状况,实现了对煤矿巷道顶板的实时在线分布式监测。现场应用结果表明,光纤应变变化能够实时准确地反映顶板变形情况,基于光纤应变的顶板监测结果与顶板离层仪监测结果、十字法观测结果一致。用光纤应变表征顶板变形程度消除了人为因素和断电等影响,保证了监测结果的客观性,这种长距离、耐腐蚀、抗干扰、无需供电的分布式光纤应变监测方式为煤矿提供了一种全新的巷道监测手段。

Coal mine roadway roof monitoring system based on distributed optical fiber technology

At present,roadway roof deformation monitoring method adopts on-line real-time monitoring based on underground industrial ring network,electronic and fiber Bragg grating displacement sensors which are connected by wireless means,has many blind spots,large errors,and relies on continuous power supply.For the above problems,coal mine roadway roof monitoring system based on distributed optical fiber technology was designed.The system uses Brillouin optical time domain reflectometer(BOTDR)as the core monitoring tool for data collection and analysis.It uses 5 mm stranded steal optical fiber as sensing fiber,and uses anchor rod and anchor cable as fixed points to lay optical cable.The strain of the optical fiber is used to monitor deformation of the roof,and the real-time online distributed monitoring of the roof of the coal mine roadway is realized.Field application results show that the fiber strain change can accurately reflect roof deformation in real time,the roof monitoring results based on fiber strain are consistent with the monitoring results of the roof delamination instrument and the cross method.Using fiber optic strain to characterize roof deformation eliminates human factors and power outages,and ensures objectivity of the monitoring results.The power-free distributed optical fiber strain monitoring method with long-distance,good corrosion-resistant and anti-interference performance provides a new way of roadway monitoring for coal mine.