Characteristics and Deformation Mechanisms of Neogene Red-Bed Soft Rock Tunnel Surrounding Rock: Insights from Field Monitoring and Experimental Analysis

This study focuses on Neogene red-bed soft rock tunnels in the Huicheng Basin, China. Through engineering geological investigation, remote wireless monitoring systems, and total station multi-parameter monitoring, the deformation characteristics of red-bed soft rock surrounding rock under high in si...

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Main Authors: Jin Wu, Geng Cheng, Zhiyi Jin, Zhize Han, Feng Peng, Jiaxin Jia
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Buildings
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Online Access:https://www.mdpi.com/2075-5309/15/11/1820
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author Jin Wu
Geng Cheng
Zhiyi Jin
Zhize Han
Feng Peng
Jiaxin Jia
author_facet Jin Wu
Geng Cheng
Zhiyi Jin
Zhize Han
Feng Peng
Jiaxin Jia
author_sort Jin Wu
collection DOAJ
description This study focuses on Neogene red-bed soft rock tunnels in the Huicheng Basin, China. Through engineering geological investigation, remote wireless monitoring systems, and total station multi-parameter monitoring, the deformation characteristics of red-bed soft rock surrounding rock under high in situ stress environments and their influencing factors were systematically analyzed. The findings reveal that the surrounding rock deformation follows a three-stage evolutionary pattern of “rapid, slow, and stable”. Construction disturbances can disrupt the stable state, leading to “deep V-shaped” anomalies or double-step responses in deformation curves. Spatially, the deformation exhibits significant anisotropy, with the haunch area showing the maximum deformation (95 mm) and the vault the minimum (65–73 mm). Deformation stabilization requires 30–42 days, and a reserved deformation of 10 cm is recommended based on specifications. Mechanical behavior analysis indicates that the stress–strain curves of red-bed argillaceous sandstone are stepped, with increased confining pressure enhancing both peak and residual strengths, validating the necessity of timely support. The study elucidates a multi-factor coupling mechanism: rock mass classification, temporal–spatial effects (excavation face constraints and rheological properties), construction methods, in situ stress levels, and support timing (timely support during the rapid phase inhibits strength degradation) significantly influence deformation evolution. The spatiotemporal distribution of surrounding rock pressure shows that invert pressure increases most rapidly, while vault pressure reaches the highest magnitude, with construction disturbances triggering stress redistribution. This research provides theoretical and practical guidance for the design, construction optimization, and disaster prevention of red-bed soft rock tunnels.
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spelling doaj-art-c09e7365ebc04f9d9631d448e4727f7f2025-08-20T03:46:38ZengMDPI AGBuildings2075-53092025-05-011511182010.3390/buildings15111820Characteristics and Deformation Mechanisms of Neogene Red-Bed Soft Rock Tunnel Surrounding Rock: Insights from Field Monitoring and Experimental AnalysisJin Wu0Geng Cheng1Zhiyi Jin2Zhize Han3Feng Peng4Jiaxin Jia5School of Civil Engineering and Architecture, Xinjiang University, Urumqi 830047, ChinaSchool of Civil Engineering and Architecture, Xinjiang University, Urumqi 830047, ChinaSchool of Civil Engineering and Architecture, Xinjiang University, Urumqi 830047, ChinaSchool of Civil Engineering and Architecture, Xinjiang University, Urumqi 830047, ChinaSchool of Civil Engineering and Architecture, Xinjiang University, Urumqi 830047, ChinaSchool of Civil Engineering and Architecture, Xinjiang University, Urumqi 830047, ChinaThis study focuses on Neogene red-bed soft rock tunnels in the Huicheng Basin, China. Through engineering geological investigation, remote wireless monitoring systems, and total station multi-parameter monitoring, the deformation characteristics of red-bed soft rock surrounding rock under high in situ stress environments and their influencing factors were systematically analyzed. The findings reveal that the surrounding rock deformation follows a three-stage evolutionary pattern of “rapid, slow, and stable”. Construction disturbances can disrupt the stable state, leading to “deep V-shaped” anomalies or double-step responses in deformation curves. Spatially, the deformation exhibits significant anisotropy, with the haunch area showing the maximum deformation (95 mm) and the vault the minimum (65–73 mm). Deformation stabilization requires 30–42 days, and a reserved deformation of 10 cm is recommended based on specifications. Mechanical behavior analysis indicates that the stress–strain curves of red-bed argillaceous sandstone are stepped, with increased confining pressure enhancing both peak and residual strengths, validating the necessity of timely support. The study elucidates a multi-factor coupling mechanism: rock mass classification, temporal–spatial effects (excavation face constraints and rheological properties), construction methods, in situ stress levels, and support timing (timely support during the rapid phase inhibits strength degradation) significantly influence deformation evolution. The spatiotemporal distribution of surrounding rock pressure shows that invert pressure increases most rapidly, while vault pressure reaches the highest magnitude, with construction disturbances triggering stress redistribution. This research provides theoretical and practical guidance for the design, construction optimization, and disaster prevention of red-bed soft rock tunnels.https://www.mdpi.com/2075-5309/15/11/1820red-bed soft rockdeformation characteristicsdeformation mechanismstunnel engineering
spellingShingle Jin Wu
Geng Cheng
Zhiyi Jin
Zhize Han
Feng Peng
Jiaxin Jia
Characteristics and Deformation Mechanisms of Neogene Red-Bed Soft Rock Tunnel Surrounding Rock: Insights from Field Monitoring and Experimental Analysis
Buildings
red-bed soft rock
deformation characteristics
deformation mechanisms
tunnel engineering
title Characteristics and Deformation Mechanisms of Neogene Red-Bed Soft Rock Tunnel Surrounding Rock: Insights from Field Monitoring and Experimental Analysis
title_full Characteristics and Deformation Mechanisms of Neogene Red-Bed Soft Rock Tunnel Surrounding Rock: Insights from Field Monitoring and Experimental Analysis
title_fullStr Characteristics and Deformation Mechanisms of Neogene Red-Bed Soft Rock Tunnel Surrounding Rock: Insights from Field Monitoring and Experimental Analysis
title_full_unstemmed Characteristics and Deformation Mechanisms of Neogene Red-Bed Soft Rock Tunnel Surrounding Rock: Insights from Field Monitoring and Experimental Analysis
title_short Characteristics and Deformation Mechanisms of Neogene Red-Bed Soft Rock Tunnel Surrounding Rock: Insights from Field Monitoring and Experimental Analysis
title_sort characteristics and deformation mechanisms of neogene red bed soft rock tunnel surrounding rock insights from field monitoring and experimental analysis
topic red-bed soft rock
deformation characteristics
deformation mechanisms
tunnel engineering
url https://www.mdpi.com/2075-5309/15/11/1820
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