Durability Study On Distributed Optical Fiber Detection For Pipeline

Distributed optical fiber sensor for pipeline with high measurement precision and long sensing length, is widely used in long distanced distributed stress monitoring, large and medium-sized construction projects and long-term stability monitoring. Distributed optical fiber sensor can overcome many weaknesses that traditional detection method, it has strong anti-electromagnetic interference ability, safe and reliable property. Besides the fiber cable has oxidation resistance, anti-acid and alkali corrosion ability and long service life. So laying a sensing fiber in the paving of the pipeline can achieve long-term, distributed real-time online monitoring for the whole pipeline system. To further determine the practical application of the distributed optical fiber sensor in the real-time monitoring for all life of buried pipeline, this thesis carry out the indoor test of the sensor in and out the tube for distributed optical fiber sensing technology. At present, the research about this aspect is still very limited in home and abroad.The paper includes scour of the inner tube sensor by liquid inside the tube, the influence of the inner tube sensor by temperature out of the tube and striking and protective measures by random load out of the tube. The detailed content of dissertation is as following:(1) This paper describes the development and engineering application of distributed optical fiber sensing technology, lays stress on the durability research of distributed optical fiber sensor at home and abroad.(2) Data analysis shows that temperature cycling has less impact on the performance of distributed optical fiber sensor and the detection performance of iron pipes by making the sensing properties experiment of distributed optical fiber sensor for pipeline and detection performance experiment of iron specimen under temperature cycling, so the temperature cycling can be ignored in the actual project.(3) The distributed optical fiber sensor pasted on iron specimens by building glue were flush cycle, indicating that the flush cycle has less affected to the distributed optical fiber sensor pasted in the iron specimen.(4) Data analysis shows that impacting cycling has less impact on distributed optical fiber sensor by making the striking experiment to metal-cord-strain-sensing distributed optical fiber sensor in various different free and tension states, but it should be paying attention to the protection of the steel strand in the practical project in order to avoid the formation of local deformation. These data include diagrams of fracture state and the differences between last and initial data to each striking data.(5)The paper gave the armor protection measures of distributed optical fiber sensor and made an applications simulation experiment to distributed optical fiber sensor laid on the submarine pipeline during construction by studying durability of distributed optical fiber sensor under the protection.