Research on Deformation and Failure Law of the Gob-Side Roadway in Close Extra-Thick Coal Seams

Shengquan He, Le Gao, Bin Zhao (), Xueqiu He, Zhenlei Li, Dazhao Song, Tuo Chen, Yanran Ma and Feng Shen
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Shengquan He: Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mine, University of Science & Technology Beijing, Beijing 100083, China
Le Gao: Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mine, University of Science & Technology Beijing, Beijing 100083, China
Bin Zhao: School of Safety Engineering, China University of Mining and Technology, Xuzhou 221116, China
Xueqiu He: Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mine, University of Science & Technology Beijing, Beijing 100083, China
Zhenlei Li: Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mine, University of Science & Technology Beijing, Beijing 100083, China
Dazhao Song: Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mine, University of Science & Technology Beijing, Beijing 100083, China
Tuo Chen: Department of Mining and Materials Engineering, McGill University, Montreal, QC H3A 0E8, Canada
Yanran Ma: Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mine, University of Science & Technology Beijing, Beijing 100083, China
Feng Shen: Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mine, University of Science & Technology Beijing, Beijing 100083, China

Sustainability, 2023, vol. 15, issue 3, 1-20

Abstract: To reveal the deformation and failure law of the gob-side roadway (GSR) and the main influencing factors in close extra-thick coal seams, the research methods of field monitoring, theoretical analysis, and numerical simulation are adopted in this paper. Field monitoring data shows that microseismic events occur and accumulate frequently in the surrounding rock and some overlying key layers of the GSR. Large deformation is experienced in the middle part of roadway near the solid coal side, the middle and upper parts of the roadway near the coal pillar side, and the roadway floor. The overlying strata of the GSR are fractured to form a composite structure as “low-level cantilever beam and high-level masonry beam”. The coal pillar is squeezed and effected by the composite beam structure and the rotation moment M , causing serious bulge in middle and upper part of the coal pillar side. The stability of the solid coal side of the roadway is affected by the stress transferred from gangue contact point. Numerical simulation shows that the immediate roof and key layer breakage are induced by the mining of the 30,501 working face. Shear and tension failures happen in the GSR due to overburden subsidence and rotary extrusion. The stress and displacement at the middle and upper of the roadway on the coal pillar side are larger than the other area. Compared with the solid coal side, the coal on the coal pillar side is obviously more fractured, with a lower bearing capacity. The peak stress in the coal pillar shows up 2 m away from the roadway, which is close to the length of bolt support. The mining-induced stress and the stress transferred from gangue contact point are the direct reasons for solid coal bulge beside the roadway. The peak stress on the solid coal side is located 7 m away from the roadway, at the gangue contact point where overburden fractures. The overburden strata loads and the transferred stress near the gangue contact point are transferred from the sides to the roadway floor. Their coupling effect with the in situ horizontal stress acts as the force source for the plastic floor heave.

Keywords: near coal seams; gob-side roadway; microseismicity; overburden fracture; roadway deformation (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2023
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