Abstract
Determining the reasonable coal pillar width of fully-mechanized caving mining in inclined and extra-thick coal seam is important to improve the coal recovery rate. In this study, a basic roof broken structure model of fully-mechanized caving mining was established and the distribution range of the internal stress field was calculated. Then, the evolution of stress and plastic zone of surrounding rock with different widths of coal pillar during the excavation and mining were analyzed by using FLAC3D. Finally, the deformation of surrounding rock of roadway was monitored by field test. The results show that the distribution range of internal stress field is 4.2–4.9 m and the coal pillar width is 8–35.4 m in combination with the geological conditions of the test site. During the retreat of mining face, the internal stress of the coal pillar changes from single peak to asymmetric double-peak, and the plastic zone develops gradually from the two sides of the coal pillar into the central section, producing a certain range of elastic nuclear zone. The reasonable pillar width is determined as 24 m by considering comprehensively. Field test shows that the roadway deformation is small and the surrounding rock deformation of roadway was effectively controlled. The research results provide beneficial reference for determining reasonable width of coal pillar and roadway layout with similar conditions.
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Acknowledgements
The author(s) thank the editors and anonymous reviewers for their thoughtful and detailed comments. This research was financially supported by “Thirteen-Five” National Science and Technology Major Issues of Special Tasks of China (Grant No. 2016ZX05067005-003), the National Natural Science Foundation of China (Grant No. 51604144), the National Science and Technology Major Project (Grant No. 2016ZX05067-005-004), and the Natural Science Foundation of Liaoning Province in China (Grant No. 20170540430).
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Fan, N., Wang, J., Zhang, B. et al. Reasonable Width of Segment Pillar of Fully-Mechanized Caving Face in Inclined Extra-Thick Coal Seam. Geotech Geol Eng 38, 4189–4200 (2020). https://doi.org/10.1007/s10706-020-01289-3
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DOI: https://doi.org/10.1007/s10706-020-01289-3