Optical fiber grating soil pressure sensor

Abstract

The invention belongs to an optical fiber grating earth pressure sensing method. The method is characterized in that: a bearing disc (1) is connected with a cylindrical cavity shell (6), the cylindrical cavity shell (6) is connected with a disc cover (11); the bottom end of the cylindrical cavity shell (6) is provided with two wedge-shaped blind holes (12), and two fixed legs (5) are wedged into the two wedge-shaped blind holes (12); the fixed legs (5) are provided with fixed splints (13) and buffer splints (14) respectively, the fixed splints (13) are fixed at the two ends of a force measurement grating (9), the buffer splints (14) are fixed at the two ends of a temperature compensation grating (8), after the force measurement grating (9) and the temperature compensation grating (8) are connected in series, the two ends of the connected force measurement grating (9) and the temperature compensation grating (8) are connected with an input / output optical fiber (7) by a grating port (10), wavelength values of the force measurement grating (9) and the temperature compensation grating (8) are measured by an optical fiber grating demodulator, and then a true value of the earth pressureis obtained by subtracting the wavelength value of the temperature compensation grating (8) from the wavelength value of the force measurement grating (9). The method has the advantages of high sensitivity, anti-electromagnetic interference, good stability and being capable of monitoring landslide mass deformation, subgrade settlement, tunnel roof deformation and bridge deformation for a long time.

Description

technical field [0001] The invention belongs to the field of application of fiber grating sensing to earth pressure in buildings, bridges, landslides, etc., and is specifically a fiber grating earth pressure sensor. Background technique [0002] Traditional earth pressure sensors cannot rule out the influence of temperature, have low measurement accuracy, and cannot realize distributed measurement. In the existing fiber grating earth pressure sensor, the grating is pasted on the elastic plate, and the force curve of the grating is not linear but a parabola, which will cause the distortion of the wavelength of the grating. The body noise affects the measurement results. [0003] Although in terms of temperature compensation, the existing fiber grating sensor is also pasted on the same material, this method cannot avoid errors caused by the pasting process and pasting materials, and will also reduce the authenticity of the measurement results. Contents of the invention [...

AI Technical Summary

Problems solved by technology

[0002] Traditional earth pressure sensors cannot exclude the influence of temperature, the measurement accuracy is low, and distributed measurement cannot be realized

However, in the existing fiber grating earth pressure sensor, the grating is pasted on the elastic plate. The force curve of the grating is not linear but a parabola, which will cause the distortion of the wavelength of the grating. body noise, affecting the measurement results

[0003] Although in terms of temperature compensation, the existing fiber grating sensor is also pasted on the same material, this method cannot avoid errors caused by the pasting process and pasting materials, and will also reduce the authenticity of the measurement results

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