Research On The Distributed Measurement Of Deformation Based On Stimulated Brillouin Scattering Effect

Flood control is the most important function of the dyke.if it bursts,will lead to serious disaster.In order to avoid casualties and economic losses,researching the burst mechanism,exploring a new dyke materials and improving the dyke structure are needed.In addition,monitoring the health of dyke to provide the timely warning is also needed which has important research significance and application value.With the development of science and technology,a series of new dyke detection instrument was developed,such as electromagnetic dyke leakage detector,frequency domain electromagnetic method,ground penetrating radar and so on.But these all belong to the point measurement with the shortcomings of omission,poor anti-interference and small measuring distance,it is difficult to perform the demand of the dyke health monitoring.Aiming at the above monitoring techniques,the distributed optical fiber sensing technology based on the stimulated Brillouin scattering effect is adopted to measure the micro deformation of the dyke which can measure and locate the micro deformation of the dyke.so as to monitor the deformation state of dyke in the whole life cycle,which can not only provide data for the dyke's maintenance,but also provide forewarning for the extreme state.Firstly,the sensing mechanism of the stimulated Brillouin scattering effect is analyzed,and the relationship between the Brillouin frequency shift and the strain is derived.Then the Michelson interferometer is used to verify the linear relationship between the optical fiber Brillouin frequency shift and the strain.Then producing a flow control device based on PID control,to provide accurate water flow for the dyke.Finally,constructing the experimental platform.The distributed optical fiber sensor is embedded in the dyke to research the deformation of the dyke under different hydraulic pressure.The research testify that the Brillouin frequency shift can accurately reflect the dyke deformation.The distributed optical fiber sensing technology based on the stimulated Brillouin scattering effect is appropriate for dyke health monitoring.