Soil pressure measuring method with variable measuring range based on Bragg fiber grating

Abstract

The invention belongs to the field of a soil internal pressure measuring method, and discloses a soil pressure measuring method with a variable measuring range based on a Bragg fiber grating. The method includes following steps: (1) selecting materials and dimensions of a cantilever beam and a film according to the dimension of a measured object and a measuring requirement; (2) installing a Braggfiber grating sensor on the cantilever beam to enable the Bragg fiber grating sensor and the cantilever beam to be tightly combined, connecting a free end of the cantilever beam and the film togetherthrough a rigid dowel bar, and connecting the Bragg fiber grating sensor to an optical fiber signal analysis processing device through an optical fiber; (3) fixing a fixed end of the cantilever beam to a sensor cavity, and placing a whole soil pressure transducer in the measured object; and (4) continuously measuring a strain value of the Bragg fiber grating sensor, and calculating a local pressure of the measured object. According to the method, the problem of precision measurement of soil pressure of different measuring ranges in the soil can be solved, the measuring requirement of the wide-span measuring range can be satisfied, the measuring 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 specifically relates to a variable-range soil pressure measurement 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 accurately measure the local strain and deformation in the middle of the measured object on both sides. 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 tun...

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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 accurately measure the local strain and deformation in the middle of the measured object on both sides

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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