Research On Optical Fiber Inclinometer For Railway Slope Deformation Monitoring

With the constant development of railway industry,the problem of slope deformation along railway is becoming more and more serious.Slope instability can cause significant property loss and potential safety hazards and needs to be overcome as soon as possible.It is urgent to develop the railway slope deformation monitoring and early warning technology.It is of vital importance to monitor the health condition of railway slope by proper devices,especially to find out the danger of slope deformation in time,so as to ensure the safety of railway slope.In our study,the inclinometer has been designed to monitor the deformation of railway slope,breaking through the key technology in sensor design,which is of great significance to establish a real-time on-line monitoring system and to ensure the safety of railway slope and the operation of locomotives and vehicles.The main research and achievements are as follows:Firstly,the methods and applications of slope deformation monitoring are classified and analyzed.The application of optical fiber sensing technology in railway slope monitoring and the research of optical fiber inclinometer are summarized.A new type of optical fiber inclinometer with high sensitivity is proposed for slope deformation monitoring.Secondly,an inclinometer based on a vertical pendulum and fiber Bragg grating(FBG)is proposed.In order to solve the problem of the mechanical friction during the rotation of the pendulum system,a low-damping rotation structure with a blade edge and a V-shaped groove is designed,which can greatly reduce the rotational friction.The sensitivity can be maximized by optimized the parameters of the inclinometer,and the higher tilt resolution and accuracy can be obtained by employing fiber Bragg grating Fabry-Perot cavity(FBG-FP)with high spectral resolution and demodulated by a high-resolution demodulation system.Thirdly,an optical fiber Fabry-Perot inclinometer based on white light interferometry is designed.By optimizing the fabrication process of extrinsic Fabry-Perot interferometer cavity,the core components of inclinometer are fabricated,and a non-scanning correlation demodulation method with high demodulation accuracy and low cost is proposed.The performance of the sensor in external conditions is tested,and the stability and reliability of the sensor are verified.Then,a preliminary study on the application of the designed optical fiber inclinometer in slope deformation monitoring is proposed.Two kinds of application schemes are designed.The inclination sensor is applied to the deep deformation monitoring of slope and the surface deformation monitoring of slope respectively.At last,the main contents and conclusions in this thesis are summarized,and the contents for next study are pointed out.