Detection of stress redistribution in a complex isolated coal pillar with active SVT technology
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ORIGINAL PAPER
Detection of stress redistribution in a complex isolated coal pillar with active SVT technology Xuwei Li 1,2,3,4 & Siyuan Gong 1,2,4 & Linming Dou 1,2 & Yanjiang Chai 2 Received: 4 August 2018 / Accepted: 3 September 2020 # Saudi Society for Geosciences 2020
Abstract The detection of stress redistribution in a mining area is essential for forecasting and preventing coal burst disasters in underground mining practices. Active seismic velocity tomography (SVT) is an effective way of investigating large-scale regional stress distribution. Active SVT technology was applied to a complex isolated coal pillar twice to assess coal burst hazard level and to guide the design of de-stress measures as well as to verify their de-stress effect. Test results show that high stress concentration existed in scattered zones along the boundary of the coal pillar rather than in the whole coal pillar. Qualitative comparison of the two SVT tests conducted before and after implementing de-stress measures indicates (1) if high-density wave sources and receivers are appropriately arranged, the spatio-temporal detection precision of active SVT technology could be sufficiently high to identify the de-stress effect of a single deep-hole roof blasting or a group of coal seam blasting upon their completion; (2) The implementation of de-stress measures in the isolated coal pillar area helped drive the stress concentration away from the de-stressed area to the adjacent area instead of fully eliminating the stress concentration. This stress-driving effect indicates that a possibly advisable strategy of coal burst control in the isolated coal pillar area could be driving stress concentration to the area further away from the area of high production activities rather than attempting to eliminate stress concentration. Keywords Active SVT . Isolated coal pillar . Stress redistribution . Coal burst . De-stress measures
Introduction With the increase of mining depth and mining intensity, the coal mining industry is entering an era of severe dynamic disasters due to high static stress (mining depth) and severe perturbance stress (mining intensity) (Qi and Dou 2008). The
Responsible Editor: Abdullah M. Al-Amri * Xuwei Li [email protected] 1
Key Laboratory of Deep Coal Resource Mining, Ministry of Education, China University of Mining and Technology, Xuzhou 221116, China
2
School of Mines, China University of Mining and Technology, Xuzhou 221116, China
3
State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Xuzhou 221116, China
4
Provincial Engineering Laboratory of Seismic Events Monitoring (Jiangsu), Xuzhou 221116, China
number of burst-prone coal mines increased from fifty in 1980s to roughly two hundred as of the end of 2017 in China. Coal burst, the main form of dynamic disasters in coal mines, is posing a serious threat to daily production and coal miners’ safety. In essence, coal burst is a natural disaster induced by elastic strain energy emitted in a sudden, rapid, and viol
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