%0 Journal Article
%T Multiplexed FBG Monitoring System for Forecasting Coalmine Water Inrush Disaster
%A B. Liu
%A S. C. Li
%A J. Wang
%A Q. M. Sui
%A L. C. Nie
%A Z. F. Wang
%J Advances in OptoElectronics
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/895723
%X 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. 1. Introduction As is known, FBG sensors are light weight, small size, easy to install, durable, corrosion resistant, water-proof, immune to electromagnetic interference, and so forth [1¨C3]. Furthermore, FBG sensors can be used to monitor large structures thanks to the inherent capability of multiplexing many sensors, which allows the measurement of several parameters at different places. In addition, FBG system can be employed as real-time monitor. Because of these intrinsic natures, FBG sensors are excellent for measuring static and dynamic measurement, such as temperature, strain, displacement, and pressure [4¨C9]. For FBG pressure sensors, pressure sensitivity is the main restriction. In [10] a novel FBG pressure sensor structure is proposed, which is based on a carbon fiber ribbon-wound composite cylindrical shell (CFRCCS). The sensor has a moderate measurement range (8£¿MPa) and high sensitivity (0.45£¿nm/MPa). Since FBG strain sensors are mostly encapsulated by stainless steel and other materials, they have an impact on the strain field of the surrounding rock or soil. Meanwhile, there are several kinds of FBG displacement sensors used in engineering, yet they are large in volume and imprecise. Therefore, continuing works on fiber sensors encapsulation are requisite. Meanwhile, FBG-based sensing systems have been employed in geotechnical engineering and model test
%U http://www.hindawi.com/journals/aoe/2012/895723/