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Mechanical properties and progressive failure characteristics of sandstone containing elliptical and square openings subjected to biaxial stress

Two kinds of common tunnel shapes, i.e. elliptical opening and square opening were selected for biaxial compression tests, and the influences of two kinds of opening shapes on the mechanical properties, failure characteristics and failure modes of sandstone were compared and analyzed. The complex va...

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Detalles Bibliográficos
Autores principales: Zhao, Honggang, Sun, Haitao, Zhang, Dongming, Liu, Chao
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7932157/
https://www.ncbi.nlm.nih.gov/pubmed/33661935
http://dx.doi.org/10.1371/journal.pone.0246815
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author Zhao, Honggang
Sun, Haitao
Zhang, Dongming
Liu, Chao
author_facet Zhao, Honggang
Sun, Haitao
Zhang, Dongming
Liu, Chao
author_sort Zhao, Honggang
collection PubMed
description Two kinds of common tunnel shapes, i.e. elliptical opening and square opening were selected for biaxial compression tests, and the influences of two kinds of opening shapes on the mechanical properties, failure characteristics and failure modes of sandstone were compared and analyzed. The complex variable theory and mapping functions were used to obtain the analytical stress solution around elliptical and square openings. The results show that the stability of the specimen containing an elliptical opening was better than that of the specimen containing a square opening under the same lateral stress. Compared with the elliptical opening, the local damage was formed earlier in the square opening which might be caused by a higher stress concentration around the square opening. The stress distributions around openings were influenced by the opening shape and lateral stress coefficient. The top and bottom of square opening were more prone to tensile fracture, and the distribution range of tensile was larger than that of elliptical opening. When the opening failed, the intensity of square opening failure was weaker than that of elliptical opening. On the basis of the average frequency value and the rise angle value, the failure mode of specimen containing elliptical or square opening was distinguished. It was found that the mixed tension and shear failure dominated the failure of specimens with different opening shapes, and the number of shear cracks in the specimen containing a square opening was greater than that in the specimen containing an elliptical opening. The above method of judging failure mode by acoustic emission signals was well verified by the CT images of damaged specimens.
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spelling pubmed-79321572021-03-15 Mechanical properties and progressive failure characteristics of sandstone containing elliptical and square openings subjected to biaxial stress Zhao, Honggang Sun, Haitao Zhang, Dongming Liu, Chao PLoS One Research Article Two kinds of common tunnel shapes, i.e. elliptical opening and square opening were selected for biaxial compression tests, and the influences of two kinds of opening shapes on the mechanical properties, failure characteristics and failure modes of sandstone were compared and analyzed. The complex variable theory and mapping functions were used to obtain the analytical stress solution around elliptical and square openings. The results show that the stability of the specimen containing an elliptical opening was better than that of the specimen containing a square opening under the same lateral stress. Compared with the elliptical opening, the local damage was formed earlier in the square opening which might be caused by a higher stress concentration around the square opening. The stress distributions around openings were influenced by the opening shape and lateral stress coefficient. The top and bottom of square opening were more prone to tensile fracture, and the distribution range of tensile was larger than that of elliptical opening. When the opening failed, the intensity of square opening failure was weaker than that of elliptical opening. On the basis of the average frequency value and the rise angle value, the failure mode of specimen containing elliptical or square opening was distinguished. It was found that the mixed tension and shear failure dominated the failure of specimens with different opening shapes, and the number of shear cracks in the specimen containing a square opening was greater than that in the specimen containing an elliptical opening. The above method of judging failure mode by acoustic emission signals was well verified by the CT images of damaged specimens. Public Library of Science 2021-03-04 /pmc/articles/PMC7932157/ /pubmed/33661935 http://dx.doi.org/10.1371/journal.pone.0246815 Text en © 2021 Zhao et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Zhao, Honggang
Sun, Haitao
Zhang, Dongming
Liu, Chao
Mechanical properties and progressive failure characteristics of sandstone containing elliptical and square openings subjected to biaxial stress
title Mechanical properties and progressive failure characteristics of sandstone containing elliptical and square openings subjected to biaxial stress
title_full Mechanical properties and progressive failure characteristics of sandstone containing elliptical and square openings subjected to biaxial stress
title_fullStr Mechanical properties and progressive failure characteristics of sandstone containing elliptical and square openings subjected to biaxial stress
title_full_unstemmed Mechanical properties and progressive failure characteristics of sandstone containing elliptical and square openings subjected to biaxial stress
title_short Mechanical properties and progressive failure characteristics of sandstone containing elliptical and square openings subjected to biaxial stress
title_sort mechanical properties and progressive failure characteristics of sandstone containing elliptical and square openings subjected to biaxial stress
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7932157/
https://www.ncbi.nlm.nih.gov/pubmed/33661935
http://dx.doi.org/10.1371/journal.pone.0246815
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