为了实现大坝渗流监测,提出了一种采用光谱成像技术的光纤Bragg光栅传感器和多点传感系统.基于室内实验结果,对监测系统可靠性与监测数据准确度进行和多点传感信号分辨因子分析,结果表明:用于坝体温度场检测的光线光栅传感器波长温度响应灵敏度可达0.009 1 nm/℃;由光源带宽决定的测试系统可实现多个传感器的复用.实践表明:采用光纤光栅传感系统可进行大坝渗流自动监测,特别是在系统防雷击、抗干扰性方面,与传统仪器相比具有明显优势.

In order to achieve automatic monitor the seepage of dam,a monitoring structure with fiber Bragg grating sensors using spectral imaging technique and the multi-point sensing network system is proposed.The fiber grating sensor system structure with linear InGaAs array and diffraction grating is designed.With the analysis results from laboratory of precision and reliability in seepage monitoring,the 0.009 1 nm/℃ wavelength-temperature response sensitivity of the Fiber Bragg Grating sensors used for temperature field monitoring of dam is presented.By analyzing the signal resolution factor of the multi-point sensor,the multiple sensors multiplexing of the testing system determined by dominated optical source bandwidth are researched.By using multiple fiber Bragg grating temperature sensors embedded into dam,the multi-point measurement of temperature differences is achieved to realize seepage monitoring of dam.Engineering practice shows that the system of seepage monitoring of dam has good performance in resistance to thunderbolts and disturbances as compared with conventional instruments.