Hydraulic structure, and base seepage condition distributed optical fiber identification system and method thereof

Abstract

The invention discloses a hydraulic structure, and a base seepage condition distributed optical fiber identification system and a method thereof. The system comprises a specially-produced self-controlled heat source seepage single-mode optical fiber, an optical path coupler and a synchronous controller, the synchronous controller is connected with a mode locked laser, a polarization beam splitter, an isolator, a grating pair, a diffraction grating, a reflector, a beam splitter, a nonlinear crystal, a spectrometer and a Michelson interferometer, the output end of the Michelson interferometer is connected with the optical path coupler, the output end of the optical path coupler is connected with a detector and a second optical splitter respectively, the detector is connected with a digital signal processor, the second optical splitter is connected with the digital signal processor through an amplification circuit, and the digital signal processor is connected with the synchronous controller and a gatherer respectively. The system and the method have the advantages of high precision, high spatial resolution, high sensing speed, long distance monitoring, and realization of the flowing and automation of monitoring and condition identification of the hydraulic structure in bad environment and the base seepage thereof.

Description

technical field [0001] The invention relates to a hydraulic structure and its foundation seepage monitoring system and method, in particular to a hydraulic structure and its foundation seepage status distributed optical fiber identification system and method in harsh environments. Background technique [0002] Seepage is an important factor related to the safe and long-term service of hydraulic structures, especially for earth-rock granular structures such as earth-rock dams and embankments, the problem of seepage and its impact are more prominent. It is of great significance to ensure the safety of the project to develop advanced, practical and reliable seepage measurement equipment for wading structures, strengthen its rational layout and efficient transmission and scientific processing and analysis of monitoring data, so as to accurately identify the seepage status of structures. With the rapid development of optical fiber sensing technology and the continuous expansion o...

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Problems solved by technology

[0006] The distributed optical fiber temperature sensor with integrated optical fiber Raman amplifier only amplifies and improves the analog electrical signal, but it does not fundamentally solve the problems of pulse width and signal-to-noise ratio; the distributed optical fiber Raman temperature sensor using pulse encoding technology, It is mainly aimed at single-mode fiber, and in order to improve the signal-to-noise ratio of the system and the ability to extract and distinguish signals, complex encoding and decoding techniques are required, which greatly increases the difficulty of operation and the complexity of equipment design. From its final spatial resolution In terms of the signal-to-noise ratio of the system, there are still major deficiencies; the distributed optical fiber temperature sensor using Raman correlation dual-wavelength self-calibration technology, the use of dual light sources still cannot guarantee the temperature measurement of the two channels in the same band. With the same loss, the temperature demodulation curve will still have problems such as tilt and distortion; the distributed optical fiber temperature sensor embedded in the optical switch can expand the temperature measurement optical fiber from the original one to multiple by adding an optical switch, but its accuracy and Timeliness of measurement is difficult to guarantee

[0007] On the other hand, most of the current seepage monitoring technologies based on sensing optical fibers need to use external circuits to heat the optical fibers. Therefore, not only the optical fibers used are required to have a heating function, but also a complete heating circuit must be constructed, which greatly increases production. The cost of the optical fiber, and because it is difficult to coordinate the relationship between the voltage of the external circuit and the heating optical fiber during indoor and outdoor monitoring, the produced heating optical fiber often has voltage instability or excessive phenomenon in this case, and the Because of the difficult-to-control voltage, the fiber sheath will be soft or even burnt, which will cause extremely serious harm to operators and instruments; in addition, the on-site monitoring applied to actual projects often lacks necessary safety measures, and it is difficult to lay heating circuits. Especially for water conservancy and hydropower projects such as dams, because most of them are located in remote areas and the service environment is extremely harsh, the realization of optical fiber laying and heating functions is more difficult or even impossible

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