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Advances in OptoElectronics
Volume 2012 (2012), Article ID 895723, 10 pages
http://dx.doi.org/10.1155/2012/895723
Research Article

Multiplexed FBG Monitoring System for Forecasting Coalmine Water Inrush Disaster

1Geotechnical & Structural Engineering Research Center, Shandong University, Shandong, Jinan 250061, China
2Optical Fiber Sensing Technology and Engineering Research Center, Shandong University, Shandong, Jinan 250061, China
3School of Earth Science and Engineering, Nanjing University, Jiangsu, Nanjing 210093, China

Received 7 August 2012; Revised 11 October 2012; Accepted 8 November 2012

Academic Editor: Jayanta K. Sahu

Copyright © 2012 B. Liu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This paper presents a novel fiber-Bragg-grating- (FBG-) based system which can monitor and analyze multiple parameters such as temperature, strain, displacement, and seepage pressure simultaneously for forecasting coalmine water inrush disaster. The sensors have minimum perturbation on the strain field. And the seepage pressure sensors adopt a drawbar structure and employ a corrugated diaphragm to transmit seepage pressure to the axial strain of FBG. The pressure sensitivity is 20.20 pm/KPa, which is 6E3 times higher than that of ordinary bare FBG. The FBG sensors are all preembedded on the roof of mining area in coalmine water inrush model test. Then FBG sensing network is set up applying wavelength-division multiplexing (WDM) technology. The experiment is carried out by twelve steps, while the system acquires temperature, strain, displacement, and seepage pressure signals in real time. The results show that strain, displacement, and seepage pressure monitored by the system change significantly before water inrush occurs, and the strain changes firstly. Through signal fusion analyzed it can be concluded that the system provides a novel way to forecast water inrush disaster successfully.