Title: Study on deformation and seepage characteristics of water-filled coal rocks under different mining methods

Authors: Jiabo Geng; Xiang Lan; Gaoxiong Zeng; Kui Zhao; Xiaoshuang Li; Shibin Tang

Addresses: Department of Emergency Management and Safety Engineering, Jiangxi University of Science and Technology, Ganzhou, China ' Department of Emergency Management and Safety Engineering, Jiangxi University of Science and Technology, Ganzhou, China ' Department of Emergency Management and Safety Engineering, Jiangxi University of Science and Technology, Ganzhou, China ' Department of Resource and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou, China ' Department of Urban Construction, Changzhou University, Changzhou, Jiangsu, 213000, China ' Department of Emergency Management and Safety Engineering, Jiangxi University of Science and Technology, Ganzhou, China

Abstract: Understanding the mechanical evolution of coal rock and the permeability of gas and water is crucial for deep coalbed methane (CBM) mining. Based on three classical mining methods protective coal-seam mining (PCM), top-coal caving mining (TCM), and non-pillar mining (NM), the 'gas-driven' and 'water-driven' methods are designed and carried out in a permeability test study on water-saturated coal rock. The results are as follows: 1) the 'gas-driven' can promote the seepage of water in the water-saturated coal rock more than the 'water-driven' test, and generates more dissipated energy; 2) the effective stress-strain curves of the specimens changed from the initial proposed linearity to hysteresis, and dissipated energy during hysteresis increases with increasing stress level; 3) the relative permeability of gas under two-phase seepage conditions in water-saturated coal rock (K_rg) in the TCM occupies a greater dominance by the stress and fluid repulsion, which indicates that the mining methods have less influence on the relative permeability of water under two-phase seepage conditions in water-saturated coal rock (K_rw) than on K_rg. [Received: May 23, 2024; Accepted: October 23, 2024]

Keywords: mining method; water-saturated coal rock; driving seepage; relative permeability.

DOI: 10.1504/IJOGCT.2025.149836

International Journal of Oil, Gas and Coal Technology, 2025 Vol.38 No.4, pp.443 - 476

Received: 11 May 2024
Accepted: 23 Oct 2024
Published online: 14 Nov 2025 *

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