Experimental Study on Inclination Test of Fiber Bragg Grating

Abstract

AbstractDeep displacement monitoring is an important means to monitor the deformation of slope, landslide and deep foundation pit. Traditional deep displacement monitoring uses manual inclinometer, which is time-consuming and laborious, and has large manual operation error, so it is impossible to realize automatic monitoring. It is urgent to adopt new technical means to make up for these shortcomings. Based on fiber Bragg grating sensing technology and beam bending theory, this paper establishes the calculation formula of fiber Bragg grating deep inclinometer, which can calculate the deep displacement curve of inclinometer through the change of fiber Bragg grating center wavelength; The strain sensitivity coefficient of fiber Bragg grating is calibrated by indoor calibration test. The experimental results show that the center wavelength of fiber Bragg grating has a high correlation with strain, and the relationship is linear. The strain and displacement of inclinometer tube are monitored and compared by indoor model test. The test results show that the displacement error calculated by fiber Bragg grating is 2% ~ 12%, which can meet the needs of deep displacement monitoring. The relevant conclusions provide a certain reference for the research of fiber Bragg grating deep displacement monitoring.