面向交通隧道渗漏水监测的光时域门控混沌拉曼传感

交通隧道在国家经济发展中扮演着重要角色。渗漏水病害一直是交通隧道安全和健康面临的严重问题。拉曼光纤传感技术在隧道渗漏水监测中具有重要应用前景。但是，因传感空间分辨率不足导致渗漏等级较小时由渗漏水产生的温度变化特征无法识别，造成重大灾害隐患。. 本项目针对现有拉曼光纤传感系统难以实现隧道渗漏水等级精准诊断和定位的技术瓶颈，提出一种光时域门控混沌拉曼传感方法。基于混沌拉曼反斯托克斯信号与参考信号的互相关函数短尺度时域压缩解调机理，精准探测淹没在环境温度噪声中由渗漏水产生的温度变化信息，通过相关峰延迟时间联合时域门控脉冲飞行时间探测温度变化信号精确位置；建立“温度突变特征-隧道结构-渗漏水状态”作用模型，实现隧道渗润、滴水、流水、喷水、淋瀑五种等级诊断及其渗漏点精准定位，并揭示光纤非线性拉曼散射效应与混沌激光场作用机理及影响规律，推动隧道安全监控和光纤传感领域的进一步发展。

The traffic tunnels play an important role in national economic development. Water leakage has always been a severe problem in the safety and health of traffic tunnels. The Raman fiber sensing technology has a good application prospect in tunnel water leakage monitoring. However, due to the inferior spatial resolution of the sensor, the temperature change caused by low water leakage grades cannot be distinguished, which will result in a serious disaster. . Aiming at the technical bottleneck of the existing Raman optical fiber sensing system which is difficult to accurately diagnose the leakage grades and locate the position, an optical temporal-gating chaotic Raman sensing method is proposed in this project. Based on the short-scale time-domain compression and demodulation mechanism of the cross-correlation function between the chaotic Raman anti-Stokes and the reference signal, the information of the temperature change caused by the water leakage can be accurately identified from the ambient temperature noise. And the position of the temperature change signal is precisely detected by the correlation peak delay time combined with the temporal-gating pulse flight time. The model of "temperature mutation characteristics-tunnel structure-leakage state" will be established to diagnose the grade of tunnel leakage among seeping water, dripping water, flowing water, spraying water and pouring waterfall, and to accurately detect the location of leakage points. The mechanism and influence between nonlinear Raman scattering effect of fiber and chaotic laser field will be revealed. This project will promote the development of tunnel water leakage monitoring and optical fiber sensing technology.