Optical fiber ground stress measuring system

Abstract

The invention discloses an optical fiber ground stress measuring system and belongs to the field of earth crust deformation observation and earthquake monitoring and forecasting in geophysics. The system comprises a sensing optical fiber, a reference optical fiber, ground stress transmission units and a signal processing unit; the ground stress transmission units are fixed on bedrock, and the sensing optical fiber is wound between the ground stress transmission units and can adjust prestress so as to adjust the sensitivity of the sensing optical fiber; when relative displacement is generated between the bedrock due to ground stress, the ground stress transmission units transmit a ground stress signal to the sensing optical fiber to cause stress change of the sensing optical fiber; and the signal processing unit calculates the phase change difference of the Rayleigh backscattering light of the sensing optical fiber and the reference optical fiber to obtain the ground stress information at the bedrock. According to the optical fiber ground stress measuring system of the invention, the microstructure point high-scattering-rate optical fiber is used as the sensitive unit, a sensibilization installation mode and a temperature compensation algorithm are combined, high-precision ground stress detection of a short baseline can be realized through a phase demodulation system; and distributed real-time detection is realized through cascade connection of the plurality of units and one optical fiber.

Description

technical field [0001] The invention belongs to the field of crustal deformation observation, earthquake monitoring and forecasting in geophysics, and more specifically relates to an optical fiber ground stress measurement system. Background technique [0002] Crustal deformation observation is one of the core links in the study of geological tectonic processes and geological disasters such as earthquakes and volcanoes in geophysics, and it is also the basis for the study of geomechanics. Compared with general application scenarios, the strain signal to be observed in the geological structure process is extremely weak, and the sources of interference are complex, which accordingly puts forward higher requirements for sensing and measurement technology. Indium steel rod telescopic strain gauge technology is widely used in traditional crustal strain monitoring stations. In order to achieve nano-strain level measurement resolution, the length of the sensing probe must reach ten...

AI Technical Summary

Problems solved by technology

[0005] In view of the above defects or improvement needs of the prior art, the present invention provides an optical fiber ground stress measurement system, the purpose of which is to fix the system on the bedrock and sense the ground strain on the sensing optical fiber through the ground stress transfer unit , the sensing fiber is subjected to strain to produce a phase change, and the ground stress information can be obtained by demodulating the phase change, thereby solving the technical problem of high complexity in the construction of the existing electrical geodesic extensometer

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