Study on Stress Evolution Law of Overburden under Repeated Mining in Long-Distance Double Upper Protective Layer

Sheng-Jie Fang, Bing Liang, Wei-Ji Sun, Zhan-Shan Shi, Jian-Feng Hao, Bei-Fang Wang and Xiao-Yong Zhang
Additional contact information
Sheng-Jie Fang: College of Mining, Liaoning Technical University, Fuxin 123000, China
Bing Liang: School of Mechanics and Engineering, Liaoning Technical University, Fuxin 123000, China
Wei-Ji Sun: School of Mechanics and Engineering, Liaoning Technical University, Fuxin 123000, China
Zhan-Shan Shi: College of Mining, Liaoning Technical University, Fuxin 123000, China
Jian-Feng Hao: College of Mining, Liaoning Technical University, Fuxin 123000, China
Bei-Fang Wang: College of Mining, Liaoning Technical University, Fuxin 123000, China
Xiao-Yong Zhang: College of Mining, Liaoning Technical University, Fuxin 123000, China

Energies, 2022, vol. 15, issue 12, 1-24

Abstract: Upper protective seam mining has been widely applied in China, but the theory of long-distance multiple upper protective seam mining is not yet perfect. In order to investigate the overburden stress evolution law of repetitive mining of long-distance coal seam groups, an experimental study was conducted to simulate similar materials under repeated mining conditions in the long-distance double upper protective layer in the background of Pingmei Group 8th coal mine. By analyzing the roof-collapse structure and the stress evolution law of different layers of the floor during the superposition mining, the pressure-relief range of the protective layer after the mining of the double upper protective layer was determined. The study results showed that: the pressure relief of the protective layer in the long-distance upper protective layer mining was a dynamic process. After the mining of Group D coal seam, the maximum impact depth of the bottom plate could reach 182 m, and the pressure-relief angle of the upper side of Group E coal seam was 65°, and the pressure-relief angle of the lower side was 75°. The distance behind the vertical projection of the working face of Group D was 42 m. The overlapping back mining would affect the stress distribution of Group F coal seam. The pressure-relief angle of the upper side of Group F coal seam was 88°, and the pressure-relief angle of the lower side was greater than 78°. The distance behind the vertical projection of the working face of Group E was less than 61 m. The superposition and staggered mining of double protective layers could expand the protective layer. Through the verification of the measurement of gas parameters on site, it can be seen from the results that it has a certain protection effect. The research results can enrich the theory of long-distance multiple upper protective layer mining, and provide theoretical guidance for long-distance Coal Seam Group Mining in Pingmei coal-mine area.

Keywords: upper protective layer; long-distance; repeated mining; stress evolution (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2022
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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