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Title: Closure of Fracture Due to Cover Stress Re-establishment After Coal Mining

Abstract

In situ measurements of deformations, stresses, and closure of fractures, affecting water inflow following coal mining, are challenging due to the inaccessibility of fractured rock. Here, the authors studied the closure process of the fractured rock mass with the cover stress re-establishment based on a theoretical analysis and a scale model testing. A quantitative analysis is used to study the fracture distribution in the fractured zone. A function to describe a fracture aperture distribution in the fractured zone is proposed, which takes into account the curvature and thickness of the fractured rock. The theoretical analysis and a scale model testing both indicate that the cover stress re-establishment with mining distance increasing and the relationship between the fracture closure and cover stress re-establishment both satisfy a logarithmic function. The scale model test also shows the following features: (1) the fracture ratio (which is the fracture area divided by the total area of fracture and intact rock with a unit width in the vertical or horizontal direction) in the lower part of the fractured rock mass is greater than that in the upper part; (2) the initially fast decreased of fracture ratios is then followed by a slower decrease during the covermore » stress re-establishment process; (3) in the upper part of the rock mass, the vertical directional fractures with small apertures are being closed with cover stress re-establishment, which indicates an increase in the water resistance reducing the seepage from these parts of the fractured zone. This study improves the general understanding of the fracture closure process and cover stress re-establishment in the fractured rock mass after coal mining ceased, and provides a theoretical basis for water resource protection in case of underground coal mining.« less

Authors:
 [1];  [1];  [2];  [3];  [4];  [5]
  1. North China Univ. of Water Resources and Electric Power, Zhengzhou (China). Henan Province Key Lab. of Rock and Soil Mechanics and Structural Engineering
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Division
  3. North China Univ. of Water Resources and Electric Power, Zhengzhou (China). Collaborative Innovation Center of Water Resources Efficient Utilization and Guarantee Engineering
  4. Changjiang Inst. of Survey, Planning, Design and Research, Wuhan (China)
  5. Lutai Coal Mining Company, Jining (China). Taiping Coal Mine
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER)
OSTI Identifier:
1474971
Grant/Contract Number:  
AC02-05CH11231
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Geotechnical and Geological Engineering
Additional Journal Information:
Journal Volume: 34; Journal Issue: 5; Related Information: © 2016, Springer International Publishing Switzerland.; Journal ID: ISSN 0960-3182
Publisher:
Springer
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; fracture closure; fractured rock mass; cover stress re-establishment; key strata; coal mining

Citation Formats

Wang, Wenxue, Jiang, Tong, Faybishenko, Boris, Wang, Zhongfu, Hu, Wei, and Zhao, Qingjie. Closure of Fracture Due to Cover Stress Re-establishment After Coal Mining. United States: N. p., 2016. Web. doi:10.1007/s10706-016-0059-x.
Wang, Wenxue, Jiang, Tong, Faybishenko, Boris, Wang, Zhongfu, Hu, Wei, & Zhao, Qingjie. Closure of Fracture Due to Cover Stress Re-establishment After Coal Mining. United States. https://doi.org/10.1007/s10706-016-0059-x
Wang, Wenxue, Jiang, Tong, Faybishenko, Boris, Wang, Zhongfu, Hu, Wei, and Zhao, Qingjie. 2016. "Closure of Fracture Due to Cover Stress Re-establishment After Coal Mining". United States. https://doi.org/10.1007/s10706-016-0059-x. https://www.osti.gov/servlets/purl/1474971.
@article{osti_1474971,
title = {Closure of Fracture Due to Cover Stress Re-establishment After Coal Mining},
author = {Wang, Wenxue and Jiang, Tong and Faybishenko, Boris and Wang, Zhongfu and Hu, Wei and Zhao, Qingjie},
abstractNote = {In situ measurements of deformations, stresses, and closure of fractures, affecting water inflow following coal mining, are challenging due to the inaccessibility of fractured rock. Here, the authors studied the closure process of the fractured rock mass with the cover stress re-establishment based on a theoretical analysis and a scale model testing. A quantitative analysis is used to study the fracture distribution in the fractured zone. A function to describe a fracture aperture distribution in the fractured zone is proposed, which takes into account the curvature and thickness of the fractured rock. The theoretical analysis and a scale model testing both indicate that the cover stress re-establishment with mining distance increasing and the relationship between the fracture closure and cover stress re-establishment both satisfy a logarithmic function. The scale model test also shows the following features: (1) the fracture ratio (which is the fracture area divided by the total area of fracture and intact rock with a unit width in the vertical or horizontal direction) in the lower part of the fractured rock mass is greater than that in the upper part; (2) the initially fast decreased of fracture ratios is then followed by a slower decrease during the cover stress re-establishment process; (3) in the upper part of the rock mass, the vertical directional fractures with small apertures are being closed with cover stress re-establishment, which indicates an increase in the water resistance reducing the seepage from these parts of the fractured zone. This study improves the general understanding of the fracture closure process and cover stress re-establishment in the fractured rock mass after coal mining ceased, and provides a theoretical basis for water resource protection in case of underground coal mining.},
doi = {10.1007/s10706-016-0059-x},
url = {https://www.osti.gov/biblio/1474971}, journal = {Geotechnical and Geological Engineering},
issn = {0960-3182},
number = 5,
volume = 34,
place = {United States},
year = {Fri Jul 22 00:00:00 EDT 2016},
month = {Fri Jul 22 00:00:00 EDT 2016}
}

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Works referencing / citing this record: