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.

Highlights

  • 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 [1,2,3]

  • In [10] a novel FBG pressure sensor structure is proposed, which is based on a carbon fiber ribbon-wound composite cylindrical shell (CFRCCS)

  • FBG seepage pressure sensors based on draw-bar structure and corrugated diaphragm, FBG strain sensors based on similar material blocks, FBG displacement sensors based on spring, and FBG temperature sensors based on dual-pipe structure are all designed and fabricated especially for the coalmine water inrush model test

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Summary

Introduction

FBG sensors are light weight, small size, easy to install, durable, corrosion resistant, water-proof, immune to electromagnetic interference, and so forth [1,2,3]. 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 [4,5,6,7,8,9]. The aims of our research project are to get the relation of temperature, strain, displacement, and seepage pressure with water inrush to analyze the formation mechanism of water inrush by using a geological model test, and to successfully forecast the impending disaster employing a fiber-optic sensing system. FBG seepage pressure sensors based on draw-bar structure and corrugated diaphragm, FBG strain sensors based on similar material blocks, FBG displacement sensors based on spring, and FBG temperature sensors based on dual-pipe structure are all designed and fabricated especially for the coalmine water inrush model test. The experimental results are shown here, and the prototype forecasts water inrush about 35 minutes before the collapse of the roof of the mine area

Development of FBG Sensors
Development of the System
Application in Coalmine Water Inrush Model Test
Conclusion
Full Text
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