Soil pressure measurement device and method with variable range based on fiber Bragg grating

Abstract

The invention belongs to the field of soil internal pressure measurement methods, and discloses a variable-range soil pressure measurement method based on a fiber Bragg grating. The variable-range soil pressure measurement method comprises the steps of (1) selecting the material and size of a cantilever beam and a thin film according to size and measurement requirements of a measured object; (2) installing a fiber Bragg grating sensor on the cantilever beam, enabling the fiber Bragg grating sensor to be tightly combined with the cantilever beam, then connecting a free end of the cantilever beam to the thin film through a rigid force transferring rod, and connecting the fiber Bragg grating sensor to optical fiber signal analysis and processing equipment through an optical fiber; (3) fixinga fixed end of the cantilever beam to a sensor cavity, and placing the whole soil pressure sensor in the measured object; and (4) continuously measuring a strain value of the fiber Bragg grating sensor, and calculating the local pressure of the measured object. According to the invention, a problem of precise measurement for soil pressure with different measuring ranges inside the soil body can besolved, measurement requirements of a long-span measuring range are met, the measurement precision of the sensor is high, and the security is high.

Description

technical field [0001] The invention belongs to the field of soil internal pressure measurement methods, and more particularly relates to a variable-range soil pressure measurement device and method based on Bragg fiber gratings. Background technique [0002] The existing local pressure measurement on the soil surface uses an electromagnetic displacement meter, which can measure the displacement between the upper and lower surfaces of the measured object, but it is difficult to measure the local strain and deformation in the middle of the measured object with high precision. However, the local small displacement will affect the calculation of the mechanical properties of the measured object. For example, the mechanical properties of the local small strain of the soil are related to the calculation of the deformation of the adjacent buildings caused by the excavation of the foundation pit, and it will also affect the calculation of the deformation caused by the excavation of t...

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Problems solved by technology

[0002] The existing local pressure measurement on the soil surface uses an electromagnetic displacement meter, which can measure the displacement between the upper and lower surfaces of the measured object, but it is difficult to measure the local strain and deformation in the middle of the measured object with high precision

However, the local small displacement will affect the calculation of the mechanical properties of the measured object. For example, the mechanical properties of the local small strain of the soil are related to the calculation of the deformation of the adjacent buildings caused by the excavation of the foundation pit, and it will also affect the calculation of the deformation caused by the excavation of the tunnel. Settlement calculation

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