Experimental study on overburden deformation evolution under mining effect based on distributed fiber optical sensing technology

HOU Gong-yu1,2 HU Tao1 LI Zi-xiang1 XIE Bing-bing1 XIAO Hai-lin1 ZHOU Tian-ci1

(1.School of Mechanics and Civil Engineering, China University of Mining and Technology, Beijing 100083)
(2.School of Mining Engineering, Xinjiang Institute of Engineering, Urumchi, Xinjiang 830091)
【Knowledge Link】dial gauge/dial indicator

【Abstract】In practical engineering, it is difficult to monitor the overburden deformation by conventional testing methods. Therefore, the Brillouin frequency shift (BFS) analysis and Brillouin optical frequency domain analysis (BOFDA) technology are adopted in this research to solve the problem. Based on the coal mining processes in the field, a 4 200 mm × 250 mm × 1 600 mm (length × width × height) overlying strata model is established in the laboratory. The deformation characteristics of overlying strata during the excavation are tested through the four horizontal sensing fibers and five vertical sensing fibers embedded in the model. Through the comparison of the experimental results with the measured displacements obtained by close-range digital image processing technology, the relationships of the BFS values with the pressure on strata working face and the evolution of overburden structure are revealed through the comprehensive analysis of the characteristics of mining overburden activity and the law of strata pressure appearance. Besides, the characterizing method of the development and evolution range of two zones based on BFS value are also obtained. The study shows that the BOFDA technology can be used to monitor the characteristics of mining overburden activity and the law of strata pressure appearance through BFS analysis. The test results provide theoretical and experimental support for the field application of distributed optical fiber testing technology in monitoring the “two zones” deformation of overlying strata in coal mines.

【Keywords】 distributed fiber optical sensing (DFOS); Brillouin frequency shift (BFS); model test; overlying strata deformation; two-zone monitoring;

【DOI】

【Funds】 Central University Major Achievement Transformation Project in Beijing (ZDZH20141141301) National Natural Science Foundation of China and Shenhua Group Co., Ltd. (U1261212, U1361210)

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(Translated by Hu P)

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This Article

ISSN:1000-7598

CN:42-1199/O3

Vol 41, No. 03, Pages 970-979

March 2020

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Article Outline

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Abstract

  • 1 Introduction
  • 2 Model test of overlying strata in the stope
  • 3 Test results and analysis
  • 4 Conclusions
  • References