scholarly journals Experimental Study on Deformation Monitoring of Bored Pile Based on BOTDR

2019 ◽  
Vol 9 (12) ◽  
pp. 2435 ◽  
Author(s):  
Lei Gao ◽  
Chuan Han ◽  
Zhongquan Xu ◽  
Yingjie Jin ◽  
Jianqiang Yan
Keyword(s):  
Optical Fiber ◽  
Noise Removal ◽  
Deformation Monitoring ◽  
Optical Time Domain Reflectometer ◽  
Fiber Sensing ◽  
Bored Pile ◽  
Sensing Technology ◽  
Optical Fiber Sensing ◽  
Unbiased Risk ◽  
Distributed Optical Fiber

In order to study the deformation of bored pile, it is necessary to monitor the strain of the pile. The distributed optical fiber sensing technology realizes the integration of sensing and transmission, which is incomparable with traditional point monitoring method. In this paper, the Brillouin optical time domain reflectometer (BOTDR) distributed optical fiber sensing technology is used to monitor the deformation of the bored pile. The raw data monitored by BOTDR is processed by the wavelet basis function, that can perform noise removal processing. Three different methods of noise removal are chosen. Through the processing, the db5 wavelet is used to decompose the deformation data of bored pile monitored by BOTDR into two layers. The decomposed high-frequency signal is denoised by the Stein-based unbiased risk threshold, rigrsure. The decomposed data is smoothed by the translational mean method, and the final data after denoising and smoothing processing is real and reliable. The results of this study will provide data support for the deformation characteristics of bored pile, and also show the advantages of distributed optical fiber sensing technology.

scholarly journals PPP-BOTDA Distributed Optical Fiber Sensing Technology and Its Application to the Baishuihe Landslide

2021 ◽  
Vol 9 ◽  
Author(s):  
Meng Zhao ◽  
Xianlong Yi ◽  
Junrong Zhang ◽  
Chengyuan Lin
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Surface Deformation ◽  
Deformation Monitoring ◽  
Landslide Monitoring ◽  
Fiber Sensing ◽  
Sensing Technology ◽  
Optical Fiber Sensing ◽  
Distributed Optical Fiber ◽  
Area Difference

Serious landslide hazards are prevalent along the Yangtze River in China, particularly in the Three Gorges Reservoir area. Thus, landslide monitoring and forecasting technology research is critical if landslide geological hazards are to be prevented and controlled. Pulse-prepump brillouin optical time domain analysis (PPP-BOTDA) distributed optical fiber sensing technology is a recently developed monitoring method with evident advantages in precision and spatial resolution. Herein, fixed-point immobilization and direct burying methods were adopted to arrange parallel distribution of the strain and temperature-compensated optical fibers along the Baishuihe landslide’s front edge, in order to carry out ground surface deformation monitoring. The strain data acquired from both optical fibers were processed with temperature compensation to obtain the actual optical fiber strain produced by deformation. Butterworth low-pass filter denoising method was employed to determine the filter order (n) and cut-off frequency (Wn). The area differences between the two optical fiber monitoring curves and the fixed horizontal axis were selected as evaluation indexes to obtain the area difference along the optical fiber. This data were then leveraged to determine the positive correlation between the area difference and the optical fiber strain variation degree. Finally, these results were compared with the GPS and field measured data. This study shows that when PPP-BOTDA technology is used for landslide surface deformation monitoring in conjunction with Butterworth filter denoising and strain area difference, the optical fiber strain variation degree analysis results are consistent with the GPS monitoring data and the actual landslide deformation. As such, this methodology is highly relevant for reducing the workload and improving the monitoring precision in landslide monitoring, which in turn will protect lives and property.

Pipeline corrosion and leakage monitoring based on the distributed optical fiber sensing technology

Measurement ◽  
2018 ◽  
Vol 122 ◽  
pp. 57-65 ◽  
Author(s):  
Liang Ren ◽  
Tao Jiang ◽  
Zi-guang Jia ◽  
Dong-sheng Li ◽  
Chao-lin Yuan ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Fiber Sensing ◽  
Sensing Technology ◽  
Optical Fiber Sensing ◽  
Leakage Monitoring ◽  
Distributed Optical Fiber ◽  
Pipeline Corrosion
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