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Classification of the loosening zones and estimation of the loosening pressures of tunnels in layered jointed rock strata

Due to the complexity of tunnels, accurate prediction of their loosening pressures in layered jointed rock strata is a very difficult engineering task. To recognize loosening patterns and estimate loosening pressures, numerical tests were employed in areas where tunnels were excavated in layered joi...

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Autores principales: Wang, Zhiwei, Ma, Weibin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: SAGE Publications 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10450484/
https://www.ncbi.nlm.nih.gov/pubmed/35593138
http://dx.doi.org/10.1177/00368504221098886
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author Wang, Zhiwei
Ma, Weibin
author_facet Wang, Zhiwei
Ma, Weibin
author_sort Wang, Zhiwei
collection PubMed
description Due to the complexity of tunnels, accurate prediction of their loosening pressures in layered jointed rock strata is a very difficult engineering task. To recognize loosening patterns and estimate loosening pressures, numerical tests were employed in areas where tunnels were excavated in layered jointed rock strata. A total of 12 influential factors, including joints, tunnel depth, and strata, were considered in each of the numerical models. Three loosening patterns were found in the numerical testing: a ringent trumpet-shaped boundary, an arch-shaped boundary, and a closing-trend trumpet-shaped loosening zone. Empirical expressions for the loosening zone boundaries were further established and, in the form of the 12 influential factors, considered in the simulation. Given the boundary function, the loosening pressures were further deduced, which were categorized according to loosening pattern, i.e., ringent trumpet shape or arch shape, and the excavation condition of whether or not the embedded depth was deeper than the soft layer. Two case studies were used to test this method. The newly-proposed method was found to perform better than existing methods, with loosening pressure values that were slightly larger than, but very close to, actual measured field data.
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spelling pubmed-104504842023-08-26 Classification of the loosening zones and estimation of the loosening pressures of tunnels in layered jointed rock strata Wang, Zhiwei Ma, Weibin Sci Prog Original Manuscript Due to the complexity of tunnels, accurate prediction of their loosening pressures in layered jointed rock strata is a very difficult engineering task. To recognize loosening patterns and estimate loosening pressures, numerical tests were employed in areas where tunnels were excavated in layered jointed rock strata. A total of 12 influential factors, including joints, tunnel depth, and strata, were considered in each of the numerical models. Three loosening patterns were found in the numerical testing: a ringent trumpet-shaped boundary, an arch-shaped boundary, and a closing-trend trumpet-shaped loosening zone. Empirical expressions for the loosening zone boundaries were further established and, in the form of the 12 influential factors, considered in the simulation. Given the boundary function, the loosening pressures were further deduced, which were categorized according to loosening pattern, i.e., ringent trumpet shape or arch shape, and the excavation condition of whether or not the embedded depth was deeper than the soft layer. Two case studies were used to test this method. The newly-proposed method was found to perform better than existing methods, with loosening pressure values that were slightly larger than, but very close to, actual measured field data. SAGE Publications 2022-05-20 /pmc/articles/PMC10450484/ /pubmed/35593138 http://dx.doi.org/10.1177/00368504221098886 Text en © The Author(s) 2022 https://creativecommons.org/licenses/by-nc/4.0/This article is distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 License (https://creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access page (https://us.sagepub.com/en-us/nam/open-access-at-sage).
spellingShingle Original Manuscript
Wang, Zhiwei
Ma, Weibin
Classification of the loosening zones and estimation of the loosening pressures of tunnels in layered jointed rock strata
title Classification of the loosening zones and estimation of the loosening pressures of tunnels in layered jointed rock strata
title_full Classification of the loosening zones and estimation of the loosening pressures of tunnels in layered jointed rock strata
title_fullStr Classification of the loosening zones and estimation of the loosening pressures of tunnels in layered jointed rock strata
title_full_unstemmed Classification of the loosening zones and estimation of the loosening pressures of tunnels in layered jointed rock strata
title_short Classification of the loosening zones and estimation of the loosening pressures of tunnels in layered jointed rock strata
title_sort classification of the loosening zones and estimation of the loosening pressures of tunnels in layered jointed rock strata
topic Original Manuscript
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10450484/
https://www.ncbi.nlm.nih.gov/pubmed/35593138
http://dx.doi.org/10.1177/00368504221098886
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