Research Of Distributed Inclination Technology Based On Fiber Bragg Grating And It's Application

Slope engineering is common in mountain highway and railway traffic.With the rapid development of infrastructure construction in China,the number of slope is growing up,in the areas of poor geological conditions,it often occurs slope instability landslide accident,what seriously threatens the safety of traffic facilities and people.It is meaningful to geological disaster warning of implementing deformation monitoring to slope,knowing its status and trend and carrying out evaluation and prediction to the stability.Traditional slope monitoring technologies often use electromagnetic sensing devices and apparatus,their signal is very vulnerable to electromagnetic interference,but also not conducive to carry out real-time monitoring.Fiber Bragg Grating is a new kind of sensing element,the sensor based on Fiber Bragg Grating has incomparable advantages with traditional sensor: use optical signal transmission,long transmission distance,unaffected by the nature electromagnetic interference;it can be connected in series to form distribution measurement and is easy to composite network;remote real-time monitoring,good stability,strong anti-interference ability.These advantages make it very suitable for real-time monitoring of the slope engineering under harsh environment.Inclination technology of slope based on Fiber Bragg Grating is mainly studied in this paper,it mainly includes three aspects:(1)A new distributed inclination method is proposed based on the existing Fiber Bragg Grating technology,introduce the measurement principle,and get the calculation formula of horizontal displacement.Compare with the existing measurement and calculation methods,its measurement and displacement calculation algorithm is more accurate.(2)According to the requirement of inclination method proposed,develop a tilt Fiber Bragg Grating sensor with enhanced sensitivity structure,on the basis of traditional tilt sensor with equal strength beam structure,describe the principle of enhanced sensitivity,and use finite element method to analyze the corresponding curve of the size of enhanced sensitivity structure and the effect of enhanced sensitivity.Manufacture three kinds of FBG tilt sensors: no enhanced sensitivity structure,enhanced sensitivity boss height is 0.5mm and 1mm,and carry out comparative experiments of range,sensitivity,linearity,repeatability,and creep test.The results show that this method is feasible and effective.(3)This technique is applied to the engineering practice.Manufacture the measuring device with high precision tilt sensor developed,and monitor deformation of the slope Anti-sliding Pile in Yongji highway Guzhang section.The deformation condition of theslope is monitored in a continuous period of several months.The long-term deformation of the anti-sliding pile is effectively monitored,which provides scientific data for the study of the stability of the slope.