Strata movement and unloading mechanism in protective layer mining of closely spaced coal seams

Author Names:
Gaofeng Song , Jingyang Xiao , Songli Jin, Guanghui Xu, Minghui Zan , Haonan Li, Dezhong Kong, Pengfei Zhang
Author Affiliation:
North China University of Technology
Author Email:
jinsongli87@163.com
Publication Date:
February 26, 2026

Page numbers:

1359-1374

DOI Number:

https://doi.org/10.66113/jcmse.26091

Abstract:

Protective layer mining is a highly effective strategy for mitigating ground pressure disasters in groups of closely spaced coal seams. This study investigates overburden movement and pressure relief mechanisms using physical simulations of protective layer extraction. Two physical models of none protective and single protective layer mining scenarios were developed to analyze the strata failure characteristics, stress distribution, overburden displacement, and roof-support interaction. Results show that the stress relief coef?cients during single protective layer mining were below 0.5, con?rming effective pressure relief. Relief was more pronounced at the panel boundaries than in the central zone. Compared with the none protective layer mining scheme, the overburden displacement in the single protective layer mining was more uniform. The overall displacement was about 11 mm, with a peak value reaching 13.5 mm. The stress relief in strata after mining a protective layer helps to mitigate stress concentration and dynamic pressure impacts during the main seam mining, thus improving the safety production and recovery rate of resources.
Keywords:
Protective layer mining, closely spaced coal seam, unloading mechanism, pressure relief effect, support-rock interaction
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