Study On Multi-Parameter Monitoring Of Embankment Based On Distributed Fiber-Optic Sensing Technology

The embankment project is an important line of defense to ensure the safety of people’s lives and properties along the embankment,and at the same time exerts a huge social and economic benefits in many aspects.Therefore,effective monitoring and evaluation of embankment engineering is of great significance for disaster prevention and mitigation.The embankment project is a kind of long-distance linear project that crosses a variety of geographic units,and its geological conditions along the route are complicated and there are many factors that induce embankment instability,therefore,multi-angle and all-round monitoring of the embankment project is required to make a reliable evaluation of the embankment stability.The existing conventional monitoring methods can hardly meet the distributed,long-distance and automated monitoring needs of embankment projects.The paper adopts various distributed fiber optic sensing technology,proposes a method for river erosion and embankment seepage monitoring,and validates it through indoor and outdoor tests;based on ultra-weak FBG technology,a set of embankment multi-parameter optical fiber monitoring system is established and applied in the embankment of Zhinan Village in Jiangsu Province.The main results of the paper are summarized as follows:(1)Based on extensive reading of relevant domestic and international literature,the current research status of embankment safety monitoring technology is summarized,and the advantages and disadvantages of different monitoring methods and applicable scenarios are introduced.The damage types and disaster-causing mechanisms of embankment instability are analyzed,the monitoring elements are identified,and the key issues in embankment safety monitoring are pointed out.The superiority of fiberoptic sensing technology over conventional monitoring technology that is difficult to replace is discussed in comparison.(2)Based on distributed temperature sensing technology(DTS)and ultra-weak FBG technology(UWFBG),we have developed and selected fiber optic sensors for embankment safety monitoring,and on the basis of which,we also developed an embankment multi-parameter optical fiber monitoring system.(3)A DTS-based river siltation and erosion monitoring method is proposed,and the feasibility of the method is verified by indoor and outdoor experiments,and two monitoring methods are given according to different application scenarios.The method has the advantages of low cost,fast response,good timeliness and real-time monitoring compared with the traditional acoustic ranging technology.(4)The feasibility test of seepage monitoring based on UWFBG temperature sensing technology was carried out,and the relationship between seepage velocity and eigenvalue temperature under different heating power was investigated,and the test results showed that the higher the flow velocity,the lower the eigenvalue temperature,and the two were negatively correlated,and the relationship between seepage velocity and eigenvalue temperature was obtained by curve fitting as a quadratic function,which verified the feasibility of UWFBG temperature sensing technology applied to seepage monitoring.(5)Based on the ultra-weak FBG technology,a multi-parameter optical fiber monitoring system for embankments was built in Zhinan Village,Jiangsu Province,and the applicability and reliability of the monitoring system was verified by monitoring data analysis.