Experimental study of strength degradation in fractured surrounding rock of deep high-temperature tunnels
Abstract Rock mechanical properties undergo significant deterioration in high-temperature environments, resulting in reduced rock mass strength and stability. To reveal the strength degradation patterns and deformation characteristics of fractured surrounding rock in deep high-temperature tunnels, t...
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Nature Portfolio
2025-08-01
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| Series: | Scientific Reports |
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| Online Access: | https://doi.org/10.1038/s41598-025-13595-y |
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| author | Haibo Jiang Jun Zhang Gang Wei Tianlong Yu |
| author_facet | Haibo Jiang Jun Zhang Gang Wei Tianlong Yu |
| author_sort | Haibo Jiang |
| collection | DOAJ |
| description | Abstract Rock mechanical properties undergo significant deterioration in high-temperature environments, resulting in reduced rock mass strength and stability. To reveal the strength degradation patterns and deformation characteristics of fractured surrounding rock in deep high-temperature tunnels, this study conducted stress path loading and unloading tests on rock specimens subjected to various high temperatures. These tests were based on the stress evolution characteristics of the fractured zone in high-temperature tunnels, using an MTS815 rock mechanics servo testing machine. Results show that high temperatures induce varying degrees of damage to rock specimens, with damage severity increasing as temperature rises. A temperature of 300 °C is identified as the critical damage-sensitive zone for high-temperature rock specimens. As temperature increases, the strength, cohesion, and internal friction angle of initially damaged high-temperature rock specimens all exhibit decreasing trends of varying magnitudes. Peak strength degradation is most significant, with a maximum reduction of 67.38% and a minimum of 18.49%. Additionally, cohesion undergoes a sudden change at 300 °C, decreasing by 44.31%, while the internal friction angle shows a less substantial reduction. Throughout the experiment, both circumferential strain and volumetric strain increase noticeably. Volumetric strain changes from negative to positive values, which signifies substantial dilation. Rock specimens that have undergone high-temperature damage exhibit clear characteristics of strain softening and residual strength following the attainment of peak strength. The ultimate macroscopic failure is primarily characterized by mechanisms associated with combined shear failure. |
| format | Article |
| id | doaj-art-1a11acfa66c8405d8fe13aa2309484ce |
| institution | Kabale University |
| issn | 2045-2322 |
| language | English |
| publishDate | 2025-08-01 |
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| spelling | doaj-art-1a11acfa66c8405d8fe13aa2309484ce2025-08-20T03:42:28ZengNature PortfolioScientific Reports2045-23222025-08-0115111310.1038/s41598-025-13595-yExperimental study of strength degradation in fractured surrounding rock of deep high-temperature tunnelsHaibo Jiang0Jun Zhang1Gang Wei2Tianlong Yu3College of Hydraulic and Civil Engineering, Xinjiang Agriculture UniversityXinjiang Water Resources and hydropower Survey Design and Research Institute limited liability companyKey Laboratory of Safe Construction and Intelligent Maintenance for Urban Shield Tunnels of Zhejiang Province, Hangzhou City UniversityXinjiang Corps Survey and Design Institute (Group) Co., LtdAbstract Rock mechanical properties undergo significant deterioration in high-temperature environments, resulting in reduced rock mass strength and stability. To reveal the strength degradation patterns and deformation characteristics of fractured surrounding rock in deep high-temperature tunnels, this study conducted stress path loading and unloading tests on rock specimens subjected to various high temperatures. These tests were based on the stress evolution characteristics of the fractured zone in high-temperature tunnels, using an MTS815 rock mechanics servo testing machine. Results show that high temperatures induce varying degrees of damage to rock specimens, with damage severity increasing as temperature rises. A temperature of 300 °C is identified as the critical damage-sensitive zone for high-temperature rock specimens. As temperature increases, the strength, cohesion, and internal friction angle of initially damaged high-temperature rock specimens all exhibit decreasing trends of varying magnitudes. Peak strength degradation is most significant, with a maximum reduction of 67.38% and a minimum of 18.49%. Additionally, cohesion undergoes a sudden change at 300 °C, decreasing by 44.31%, while the internal friction angle shows a less substantial reduction. Throughout the experiment, both circumferential strain and volumetric strain increase noticeably. Volumetric strain changes from negative to positive values, which signifies substantial dilation. Rock specimens that have undergone high-temperature damage exhibit clear characteristics of strain softening and residual strength following the attainment of peak strength. The ultimate macroscopic failure is primarily characterized by mechanisms associated with combined shear failure.https://doi.org/10.1038/s41598-025-13595-yRock mechanicsDeep high-temperature tunnelsTemperature effectsInitial damageStrength degradation |
| spellingShingle | Haibo Jiang Jun Zhang Gang Wei Tianlong Yu Experimental study of strength degradation in fractured surrounding rock of deep high-temperature tunnels Scientific Reports Rock mechanics Deep high-temperature tunnels Temperature effects Initial damage Strength degradation |
| title | Experimental study of strength degradation in fractured surrounding rock of deep high-temperature tunnels |
| title_full | Experimental study of strength degradation in fractured surrounding rock of deep high-temperature tunnels |
| title_fullStr | Experimental study of strength degradation in fractured surrounding rock of deep high-temperature tunnels |
| title_full_unstemmed | Experimental study of strength degradation in fractured surrounding rock of deep high-temperature tunnels |
| title_short | Experimental study of strength degradation in fractured surrounding rock of deep high-temperature tunnels |
| title_sort | experimental study of strength degradation in fractured surrounding rock of deep high temperature tunnels |
| topic | Rock mechanics Deep high-temperature tunnels Temperature effects Initial damage Strength degradation |
| url | https://doi.org/10.1038/s41598-025-13595-y |
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