FBG Sensor Network Embankment Dam-line Monitoring System Based On

Dam safety monitoring is an important means to ensure the safe operation of the dam, monitoring the dam systematically can grasp the working condition of the dam, when anomalies happen we can take appropriate measures to prevent the accident. Many embankment dam’s collapsing demonstrated that, due to the lack of the necessary observation of embankment dams, some security risks could not be found, which led to the dam break accident. For example, Teton earth dam in the United States was built in1975, the soil piping in the bottom of the bank slope Monolith alveolar, causing dam break, the survey consider that:one of the reasons is the lack of enough monitoring instruments and regular inspection of buildings during operation system, the dam only had a small amount of displacement monitoring seepage monitoring is not carried out. Another example is the2001Sichuan dulugou reservoir dam break casualties more than40people, mainly due to termite nests in earth dam from a leakage passage downpour and formation of piping, causing dam failure.Fiber Bragg grating sensor using Bragg center wavelength get sensing information by outside parameter’s modulation, it’s advantages is that anti-electromagnetic interference, small size, corrosion resistance, electrical insulation, easy to constitute the fiber optic sensing network and so on.In this paper, we use the characteristics of FBG sensors that it is easy to composite the sensor network and the wavelength division multiplexing technology to net the FBG sensors which have different functions, and build a FBG sensor network-based online embankment dam the monitoring system which use computer technology, communication technology and so on. Using this system we can monitor of embankment dams safety, especially monitor cracks and seepage of the dam, effectively ensuring the safe operation of the embankment dam.This paper use embankment dam as the subject object, and do some research on the application of the fiber grating in dam safety monitoring, the main innovations are as follows:(1)Taking advantage of the FBG sensors’characteristics that it is easy to make up the sensor network, several different types of fiber Bragg grating sensor which the laboratory developed composed a network of fiber optic sensing, and bring about the monitoring of the embankment dams cracks and seepage.(2)In addition to the FBG sensors are used for monitoring embankment dam cracks, GFRP single core based on the principle of Brillouin OTDR strain sensing cable is also used for distributed monitoring embankment dam cracks.(3)Dam safety monitoring information management system had been developed according to the specific circumstances of the subject embankment dams. It uses the related physical mode to convert wavelength data which the FBG sensors feedback into the parameters to be tested, such as cracks value, osmotic pressure. And it shows the process of change of the parameter being measured in the shape of intuitive curve diagram.(4)The system of dam safety monitoring information uses the trend equation fitting in t he time series prediction method, and has realized the pressure trend analysis of earth and r ockfill dam cracks.