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Creep and permeability evolution behavior of red sandstone containing a single fissure under a confining pressure of 30 MPa

The long-term deformation and permeability evolution with time are key issues for geo-engineering applications such as radioactive waste disposal. Rock permeability concurrent with deformation is significantly influenced by cracking. This study investigated the creep-permeability evolution behavior...

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Autores principales: Yang, Sheng-Qi, Hu, Bo
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7002402/
https://www.ncbi.nlm.nih.gov/pubmed/32024874
http://dx.doi.org/10.1038/s41598-020-58595-2
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author Yang, Sheng-Qi
Hu, Bo
author_facet Yang, Sheng-Qi
Hu, Bo
author_sort Yang, Sheng-Qi
collection PubMed
description The long-term deformation and permeability evolution with time are key issues for geo-engineering applications such as radioactive waste disposal. Rock permeability concurrent with deformation is significantly influenced by cracking. This study investigated the creep-permeability evolution behavior of red sandstone specimens containing a single fissure under a confining pressure of 30 MPa. First, the effects of stress ratio (SR) and fissure dip angle on the creep behavior of rock were investigated. The more loading/unloading cyclic numbers, the larger the irrecoverable axial deformation. The instant elastic strains and visco-elastic strains linearly increased with SR for both the intact and fissured specimens, whereas the instant plastic strains showed different results. The visco-plastic strains nonlinearly increased. For fissured and intact specimens, the creep strains and the steady-state creep rates nonlinearly increased as SR increased. The instantaneous strains, instant elastic strains, and visco-elastic strains slightly varied when the fissure dip angle was less than 45° but notably decreased with increasing fissure dip angle beyond 45°. However, the fissure dip angle had no obvious effects on the plastic and creep strains. Damage (D) was defined using the ratio of non-elastic strains to the total strain. D increased approximately linearly with SR, but the fissure dip angle had no obvious influences. Subsequently, the long-term strength (LTS) of the red sandstone was determined using two different methods. The LTS first decreased when the fissure dip angle increased from 0 to 45° but increased with increasing dip angle. The triaxial and creep failure modes were mainly shear along anti-wing cracks for the fissured specimens but shear failure occurred for the intact specimen. Moreover, the permeability of the fissured red sandstone was governed by SR and deformation or time. During the multi-step loading/unloading creep process, the permeability first decreased and then had a sudden rise when tertiary creep occurred.
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spelling pubmed-70024022020-02-14 Creep and permeability evolution behavior of red sandstone containing a single fissure under a confining pressure of 30 MPa Yang, Sheng-Qi Hu, Bo Sci Rep Article The long-term deformation and permeability evolution with time are key issues for geo-engineering applications such as radioactive waste disposal. Rock permeability concurrent with deformation is significantly influenced by cracking. This study investigated the creep-permeability evolution behavior of red sandstone specimens containing a single fissure under a confining pressure of 30 MPa. First, the effects of stress ratio (SR) and fissure dip angle on the creep behavior of rock were investigated. The more loading/unloading cyclic numbers, the larger the irrecoverable axial deformation. The instant elastic strains and visco-elastic strains linearly increased with SR for both the intact and fissured specimens, whereas the instant plastic strains showed different results. The visco-plastic strains nonlinearly increased. For fissured and intact specimens, the creep strains and the steady-state creep rates nonlinearly increased as SR increased. The instantaneous strains, instant elastic strains, and visco-elastic strains slightly varied when the fissure dip angle was less than 45° but notably decreased with increasing fissure dip angle beyond 45°. However, the fissure dip angle had no obvious effects on the plastic and creep strains. Damage (D) was defined using the ratio of non-elastic strains to the total strain. D increased approximately linearly with SR, but the fissure dip angle had no obvious influences. Subsequently, the long-term strength (LTS) of the red sandstone was determined using two different methods. The LTS first decreased when the fissure dip angle increased from 0 to 45° but increased with increasing dip angle. The triaxial and creep failure modes were mainly shear along anti-wing cracks for the fissured specimens but shear failure occurred for the intact specimen. Moreover, the permeability of the fissured red sandstone was governed by SR and deformation or time. During the multi-step loading/unloading creep process, the permeability first decreased and then had a sudden rise when tertiary creep occurred. Nature Publishing Group UK 2020-02-05 /pmc/articles/PMC7002402/ /pubmed/32024874 http://dx.doi.org/10.1038/s41598-020-58595-2 Text en © The Author(s) 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Yang, Sheng-Qi
Hu, Bo
Creep and permeability evolution behavior of red sandstone containing a single fissure under a confining pressure of 30 MPa
title Creep and permeability evolution behavior of red sandstone containing a single fissure under a confining pressure of 30 MPa
title_full Creep and permeability evolution behavior of red sandstone containing a single fissure under a confining pressure of 30 MPa
title_fullStr Creep and permeability evolution behavior of red sandstone containing a single fissure under a confining pressure of 30 MPa
title_full_unstemmed Creep and permeability evolution behavior of red sandstone containing a single fissure under a confining pressure of 30 MPa
title_short Creep and permeability evolution behavior of red sandstone containing a single fissure under a confining pressure of 30 MPa
title_sort creep and permeability evolution behavior of red sandstone containing a single fissure under a confining pressure of 30 mpa
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7002402/
https://www.ncbi.nlm.nih.gov/pubmed/32024874
http://dx.doi.org/10.1038/s41598-020-58595-2
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