Underwater soft medium-oriented optical fiber topography change sensor

Abstract

The invention relates to an optical fiber topography change sensor, and particularly discloses an underwater soft medium-oriented optical fiber topography change sensor. The sensor comprises a first coupling structure and a second coupling structure which are buried in an underwater soft medium and coupled to the soft medium; a corrugated pipe of which the two ends are respectively connected with the first coupling structure and the second coupling structure; an elastic connecting structure which is located in the corrugated pipe and has one end connected with the first coupling structure; and a fiber Bragg grating of which one end is connected with the elastic connecting structure the other end is connected with the second coupling structure, and two free ends extend out of the first coupling structure and the second coupling structure through through holes respectively. According to the invention, deformation measurement of an underwater soft medium is realized on the basis of a small structure, and the sensor has the advantages of small size and simple structure; and the sensor can be effectively coupled to a soft medium, is high in measurement precision, is not limited by the maximum dependent variable of an optical fiber, and enlarges the measurement range.

Description

technical field [0001] The invention relates to an optical fiber deformation sensor, in particular to an optical fiber deformation sensor facing underwater soft media. Background technique [0002] Through seabed deformation observation and seabed stability monitoring, seabed deformation data caused by submarine landslides, land reclamation, natural gas hydrate and other resource development can be obtained, so as to better analyze the occurrence mechanism of submarine landslides and other geological disasters, and provide marine engineering It is of great significance to predict the occurrence of geological disasters and ensure the stability of marine engineering by providing a more effective early warning method for the safety of marine engineering. [0003] Submarine deformation observation needs to bury measuring instruments in the seabed in advance, which is difficult and expensive. Submarine geology is mostly soft media such as sediment, and it is difficult to couple ...

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Problems solved by technology

Due to the problems of power supply, long-distance transmission signal attenuation, non-waterproof, and difficult reuse of electronic sensors, the layout is difficult, the system is complicated and the cost is high

[0006] The Scripps Institute of Oceanography at the University of California in the United States uses optical fiber sensors to observe the structural strain of the seafloor. The observation is similar to the observation method of ground fissures in land areas. The optical fiber is flattened on the surface of the seabed and anchored at both ends, and the stretched length of the optical fiber is measured to reflect the strain. The measurement accuracy of the lateral deformation of the regional seabed can reach the millimeter level, but due to the limited tensile strength of the optical fiber, the measurement range is small, and the local deformation cannot be measured in a distributed manner

[0007] Duan Xiyun and others have designed a fiber grating strain sensor that can be used in harsh underwater environments for a long time, so that the fiber grating strain sensor can work underwater in a sealed waterproof structure, but for most underwater environments such as the seabed, Most of them are soft media such as sediment, the sensor is not easy to couple, and there is a hydrostatic pressure environment, which is easy to interfere with the measurement results of the sensor

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