Spatiotemporal evolutionary characteristics of asymmetric stress transfer in overburden of steeply dipping coal seams

Authors

ZHU Kaipeng, Shaanxi Key Laboratory of Prevention and Control Technology Coal Mine Water Hazard, Xi’an 710077, China CCTEG Xi’an Research Institute (Group) Co., Ltd., Xi’an 710077, China; State Key Laboratory of Coal Mine Disaster Prevention and Control, Xi’an 710077, ChinaFollow
LI Zhilin, Key Laboratory of Western Mine Exploitation and Hazard Prevention, Ministry of Education, Xi’an University of Science and Technology, Xi’an 710054, China
LUO Shenghu, Key Laboratory of Western Mine Exploitation and Hazard Prevention, Ministry of Education, Xi’an University of Science and Technology, Xi’an 710054, ChinaFollow
XIE Panshi, Key Laboratory of Western Mine Exploitation and Hazard Prevention, Ministry of Education, Xi’an University of Science and Technology, Xi’an 710054, China
FAN Juan, CCTEG Xi’an Research Institute (Group) Co., Ltd., Xi’an 710077, China
WANG Tong, Key Laboratory of Western Mine Exploitation and Hazard Prevention, Ministry of Education, Xi’an University of Science and Technology, Xi’an 710054, China
TIAN Chengyang, Key Laboratory of Western Mine Exploitation and Hazard Prevention, Ministry of Education, Xi’an University of Science and Technology, Xi’an 710054, China
YAN Zhuangzhuang, Key Laboratory of Western Mine Exploitation and Hazard Prevention, Ministry of Education, Xi’an University of Science and Technology, Xi’an 710054, China

Abstract

Objective The key to the safe and efficient mining of steeply dipping coal seams is the effective control of the stability of surrounding rocks, while the effective control is underpinned by identifying and revealing the spatiotemporal evolutionary characteristics of the stress transfer path of the overburden. Methods This study investigated mining face 25221 of a coal mine in Xinjiang through field measurement, physical simulations using similar materials, and numerical computation. This study determined the rock pressure behavior of the mining face, along with the deformation and failure patterns of the overburden, through a comprehensive analysis. Accordingly, it established stress characteristic components dominated by shear and normal stresses and explored the spatiotemporal evolutionary characteristics of the stress transfer path of the overburden. [Results and Conclusions] The results indicate that in the mining process along the mining face, the surrounding rock structure along the roof inclination exhibited an asymmetric distribution characterized by large collapse heights in the middle and upper parts but small collapse heights in the lower part. In contrast, the surrounding rock structure along the roof strike manifested a periodic evolutionary pattern as the mining face advanced. Consequently, the mining-induced stress in the roof exhibited transferred asymmetrically along the roof inclination but symmetrically along the roof strike as the mining face advanced. As shown in the profiles along the mining face inclination and strike, the stress characteristic components of the roof, which were bounded by the shear stress boundary, transferred along the coals around the goaf, manifesting an n-shaped transfer path. With an increase in the advancement distance of the mining face, the stress transfer path shifted from an m-shaped pattern to a double n-shaped pattern connected at the center. The peak abutment pressure of the coals on both sides of the goaf increased initially and then stabilized. Within the profile where the roof was parallel to the coal seams, the roof stress boundary displayed a w-shaped distribution. Specifically, the roof stress transferred unidirectionally from its boundary to the goaf center but bidirectionally from its boundary to the coal wall. With an increase in the roof horizon, the stress boundary evolved into a v-shaped pattern. The results of this study reveal the spatiotemporal evolutionary characteristics of the asymmetric roof stress transfer of steeply dipping coal seams, holding great significance for enriching the rock-layer control theory of steeply dipping coal seams.

Keywords

steeply dipping coal seam, mining stress, shear stress, stress direction, transfer path

DOI

10.12363/issn.1001-1986.24.06.0392

Recommended Citation

ZHU Kaipeng, LI Zhilin, LUO Shenghu, et al. (2024) "Spatiotemporal evolutionary characteristics of asymmetric stress transfer in overburden of steeply dipping coal seams," Coal Geology & Exploration: Vol. 52: Iss. 10, Article 13.
DOI: 10.12363/issn.1001-1986.24.06.0392
Available at: https://cge.researchcommons.org/journal/vol52/iss10/13

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