Real-time Monitoring System Of Building Tilt Based On Optical Fiber Sensor

Fiber optic sensors are widely used in the field of strain monitoring,especially in the field of construction.Foundation settlement and building inclination will lead to building damage.This paper studies the research status of all kinds of optical fiber sensors at home and abroad.With the aim of monitoring foundation settlement and building inclination,a real-time monitoring system for building inclination is established by combining optical transceiver,optical fiber microbending sensing technology and database technology.The main work is as follows:1)Based on the analysis and study of various optical fiber sensors for strain detection,a point-type optical fiber micro-bending sensor technology with strong environmental adaptability,high accuracy of fixed-point measurement and no need of position calibration is selected to complete the overall design of the real-time monitoring system for building tilt.2)Complete the design of hardware and software modules.The hardware module of the system consists of four parts: optical transmitter module,optical microbend sensor,optical receiving and amplifying module,signal conversion module and so on.The optical transmitter module uses the transmitter of easy network integration and low-cost optical transceiver as the light source,compares the influence of different optical wavelength on measurement through experiments,and finally chooses 1550 wavelength optical transceiver as the optical transmitter module.Building settlement sensor system includes optical fiber micro-bending sensor and pressure plate.The optical receiving and amplifying module converts the optical loss into small current and voltage value in turn,and the signal conversion module converts the voltage value into digital analog and transmits it to the host computer.Finally,the data are calculated,displayed and uploaded to the database through the host computer software.3)Complete the construction of the test system and carry out the test experiments of each module component and the whole system.The experimental results show that the relationship between the optical carrier intensity transmitted in the optical fiber and the compression value of the spiral micro-bending sensor in the micro-bendingdisplacement sensor is approximately linear within the measurement range.The system has a good response to soil strain.The maximum full range error of the inclination of the system is 6.3%,the settlement measurement range is 11 mm,the maximum error of the settlement ratio ? is 0.023,and the maximum inclination is0.023.The error is 0.00051.