The Research Of Fiber Grating Displacement Sensor And Its Application In Pipe Gallery Monitoring

With the development of our national modernization,the comprehensive pipeline corridor has developed rapidly with its advantages over traditional pipelines such as intensive design and unified management mode.However,when damage occurred in the composite pipe gallery without timely monitoring,and cannot be repaired in time,it may cause serious damage to the internal pipe network,and the resulting economic loss and social impact more seriously than the traditional pipeline.Therefore,the online monitoring of underground composite pipe gallery is of great significance.Because of the complexity of the internal pipeline of the underground composite pipeline corridor and the demand for the accuracy of monitoring,the fiber Bragg grating(FBG)sensor with its advantages,is the first choice for the health monitoring of the underground composite pipeline corridor structure.The first chapter firstly introduces the main composition and classification of underground composite pipe gallery structure,its construction significance,and introduces the development history and status quo of underground composite pipe gallery at domestic and overseas?Then,according to the characteristics of the underground composite pipe gallery and the analysis of common diseases,the necessity of online monitoring of the underground composite pipe gallery is explained.And then,the existing fracture technology measurement techniques and their shortcomings are briefly introduced.Finally,the principle and advantages of FBG sensor monitoring are briefly introduced,the development history of FBG sensor is summarized,thenThe sensing principle of fiber Bragg grating is firstly introduced in the second chapter.Then the paper introduces two kinds of fiber Bragg grating displacement sensor based on the principle,and briefly introduces its structure principle,fiber Bragg grating sensor packaging principle and its temperature-insensitive principle.The displacement sensitivity coefficient of fiber Bragg grating displacement sensor calibration experiment is firstly introduced in the third chapter,which is verified that the displacement of the displacement sensor has a linear relationship with the wavelength of FBG,and its linear fitting degree is above 0.999.Then,the temperature sensitivity calibration experiment of the fiber Bragg grating displacement sensor is compared with the naked fiber Bragg grating temperature calibration experiment,which is verified that the sensor can realize temperature self-compensation with only one FBG.And then,the consistency and stability of the sensor are tested.Firstly,the fourth chapter paper briefly introduces the project profile of the underground comprehensive pipe gallery in Ningbo.And then,based on the project profile the monitoring scheme and the monitoring point of the sensor are designed.Finally,the monitoring data in the project are analyzed.The fifth chapter introduces the conclusion of this paper,expounds the deficiency of the research on this subject and prospects the research direction of this subject.