A comparison study of face stability between the entering and exiting a shallow-buried tunnel with a front slope

Worldwide, it is a great challenge to tunnel in portal section, where excessive deformation, cracking, or even collapse often occurs during the construction process. This paper presents a comparison study of face stability between entering and exiting a shallow-buried tunnel with a front slope. Firs...

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Main Authors: Xinzhe Li, Xiulei Li, Chao Yang
Formato: Artigo
Idioma:English
Publicado em: Frontiers Media S.A. 2022-08-01
Colecção:Frontiers in Earth Science
Assuntos:
Acesso em linha:https://www.frontiersin.org/articles/10.3389/feart.2022.987294/full
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author Xinzhe Li
Xiulei Li
Chao Yang
author_facet Xinzhe Li
Xiulei Li
Chao Yang
author_sort Xinzhe Li
collection DOAJ
description Worldwide, it is a great challenge to tunnel in portal section, where excessive deformation, cracking, or even collapse often occurs during the construction process. This paper presents a comparison study of face stability between entering and exiting a shallow-buried tunnel with a front slope. Firstly, the theoretical solutions of support pressure σT and safety coefficient FS of the excavation face considering surface slope are derived by upper-bound limit analysis method. Secondly, for different slope angles, buried depth and surrounding rocks of the exit and entrance sections, the σT and FS are obtained. The results show that when the burial depth of the tunnel crown h remain constant, the σT increased first and then decreased while the FS increased gradually, and both become steady when the slope angle α arrive at a certain value. In addition, the thicker the h is, the smaller the certain value α is. When the h and α remain constant, the loose area in front of the excavate face will decreased apparently with the increase of the internal friction angle φ, thus the σT will decrease and FS will increase. Moreover, the σT decreased linearly with the increase of cohesion c and unit weigh γ of surrounding rock, while the FS is the opposite. Compared with the entrance section, the construction risk at the exit section is greater.
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spelling doaj.art-e2912c9aeb824a0b9cc7c2523f3d90df2022-12-22T04:28:13ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632022-08-011010.3389/feart.2022.987294987294A comparison study of face stability between the entering and exiting a shallow-buried tunnel with a front slopeXinzhe Li0Xiulei Li1Chao Yang2Key Laboratory of Geological Hazards on Three Gorges Reservoir Area, Ministry of Education, China Three Gorges University, Yichang, ChinaCollege of Traffic and Transportation, Chongqing Jiaotong University, Chongqing, ChinaKey Laboratory of Geological Hazards on Three Gorges Reservoir Area, Ministry of Education, China Three Gorges University, Yichang, ChinaWorldwide, it is a great challenge to tunnel in portal section, where excessive deformation, cracking, or even collapse often occurs during the construction process. This paper presents a comparison study of face stability between entering and exiting a shallow-buried tunnel with a front slope. Firstly, the theoretical solutions of support pressure σT and safety coefficient FS of the excavation face considering surface slope are derived by upper-bound limit analysis method. Secondly, for different slope angles, buried depth and surrounding rocks of the exit and entrance sections, the σT and FS are obtained. The results show that when the burial depth of the tunnel crown h remain constant, the σT increased first and then decreased while the FS increased gradually, and both become steady when the slope angle α arrive at a certain value. In addition, the thicker the h is, the smaller the certain value α is. When the h and α remain constant, the loose area in front of the excavate face will decreased apparently with the increase of the internal friction angle φ, thus the σT will decrease and FS will increase. Moreover, the σT decreased linearly with the increase of cohesion c and unit weigh γ of surrounding rock, while the FS is the opposite. Compared with the entrance section, the construction risk at the exit section is greater.https://www.frontiersin.org/articles/10.3389/feart.2022.987294/fullshallow-buried tunnelface stabilityupper-bound limit analysistunnel entrancetunnel exit
spellingShingle Xinzhe Li
Xiulei Li
Chao Yang
A comparison study of face stability between the entering and exiting a shallow-buried tunnel with a front slope
Frontiers in Earth Science
shallow-buried tunnel
face stability
upper-bound limit analysis
tunnel entrance
tunnel exit
title A comparison study of face stability between the entering and exiting a shallow-buried tunnel with a front slope
title_full A comparison study of face stability between the entering and exiting a shallow-buried tunnel with a front slope
title_fullStr A comparison study of face stability between the entering and exiting a shallow-buried tunnel with a front slope
title_full_unstemmed A comparison study of face stability between the entering and exiting a shallow-buried tunnel with a front slope
title_short A comparison study of face stability between the entering and exiting a shallow-buried tunnel with a front slope
title_sort comparison study of face stability between the entering and exiting a shallow buried tunnel with a front slope
topic shallow-buried tunnel
face stability
upper-bound limit analysis
tunnel entrance
tunnel exit
url https://www.frontiersin.org/articles/10.3389/feart.2022.987294/full
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