Effect of Axial In-Situ Stress in Deep Tunnel Analysis Considering Strain Softening and Dilatancy
In many previous tunnel analyses, the axial in-situ stress was ignored. In this work, its effect on the deformation and failure of the surrounding rock of a deep tunnel was revealed, considering the objective strain softening and dilatancy behavior of the surrounding rock. Analysis based on the incr...
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MDPI AG
2020-03-01
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| Series: | Energies |
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| Online Access: | https://www.mdpi.com/1996-1073/13/6/1502 |
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| author | Kang Yi Zhenghe Liu Zhiguo Lu Junwen Zhang Shuangyong Dong |
| author_facet | Kang Yi Zhenghe Liu Zhiguo Lu Junwen Zhang Shuangyong Dong |
| author_sort | Kang Yi |
| collection | DOAJ |
| description | In many previous tunnel analyses, the axial in-situ stress was ignored. In this work, its effect on the deformation and failure of the surrounding rock of a deep tunnel was revealed, considering the objective strain softening and dilatancy behavior of the surrounding rock. Analysis based on the incremental plastic flow theory was conducted, and C++ was used to write a constitutive model for numerical simulation to verify and further analyze this effect. Then, the results were validated by the field monitoring data of a coal mine gateway. Results show that the effect of the axial in-situ stress <i>σ</i><sub>a0</sub> is more significant when strain softening is considered, compared with the results of a perfectly elastoplastic model. When the axial stress <i>σ</i><sub>a</sub> is <i>σ</i><sub>1</sub> or <i>σ</i><sub>3</sub> at the initial yield, an increase or decrease in <i>σ</i><sub>a0</sub> intensifies the deformation and failure of the surrounding rock. When <i>σ</i><sub>a</sub> is <i>σ</i><sub>2</sub> at the initial yield, 3D plastic flow partly controlled by <i>σ</i><sub>a</sub> may occur, and an increase in <i>σ</i><sub>a0</sub> intensifies the deformation and failure of the surrounding rock. The effect of <i>σ</i><sub>a0</sub> will be amplified by considering dilatancy. Considering both strain softening and dilatancy, when <i>σ</i><sub>a0</sub> is close to the tangential in-situ stress <i>σ</i><sub>t0</sub> or significantly greater than <i>σ</i><sub>t0</sub> (1.5 times), <i>σ</i><sub>a</sub> will be <i>σ</i><sub>2</sub> or <i>σ</i><sub>1</sub> at the initial yield, and then 3D plastic flow will occur. In the deformation prediction and support design of a deep tunnel, <i>σ</i><sub>a0</sub> should not be ignored, and the strain softening and dilatancy behavior of the surrounding rock should be accurately considered. |
| first_indexed | 2024-04-14T06:30:48Z |
| format | Article |
| id | doaj.art-75672ab3460741a1bf9547c0de8a0ff2 |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-04-14T06:30:48Z |
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| spelling | doaj.art-75672ab3460741a1bf9547c0de8a0ff22022-12-22T02:07:37ZengMDPI AGEnergies1996-10732020-03-01136150210.3390/en13061502en13061502Effect of Axial In-Situ Stress in Deep Tunnel Analysis Considering Strain Softening and DilatancyKang Yi0Zhenghe Liu1Zhiguo Lu2Junwen Zhang3Shuangyong Dong4School of Energy & Mining Engineering, China University of Mining and Technology (Beijing), Beijing 100083, ChinaKey Laboratory of In-situ Property-improving Mining of Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, ChinaMining and Designing Branch, China Coal Research Institute, Beijing 100013, ChinaSchool of Energy & Mining Engineering, China University of Mining and Technology (Beijing), Beijing 100083, ChinaMining and Designing Branch, China Coal Research Institute, Beijing 100013, ChinaIn many previous tunnel analyses, the axial in-situ stress was ignored. In this work, its effect on the deformation and failure of the surrounding rock of a deep tunnel was revealed, considering the objective strain softening and dilatancy behavior of the surrounding rock. Analysis based on the incremental plastic flow theory was conducted, and C++ was used to write a constitutive model for numerical simulation to verify and further analyze this effect. Then, the results were validated by the field monitoring data of a coal mine gateway. Results show that the effect of the axial in-situ stress <i>σ</i><sub>a0</sub> is more significant when strain softening is considered, compared with the results of a perfectly elastoplastic model. When the axial stress <i>σ</i><sub>a</sub> is <i>σ</i><sub>1</sub> or <i>σ</i><sub>3</sub> at the initial yield, an increase or decrease in <i>σ</i><sub>a0</sub> intensifies the deformation and failure of the surrounding rock. When <i>σ</i><sub>a</sub> is <i>σ</i><sub>2</sub> at the initial yield, 3D plastic flow partly controlled by <i>σ</i><sub>a</sub> may occur, and an increase in <i>σ</i><sub>a0</sub> intensifies the deformation and failure of the surrounding rock. The effect of <i>σ</i><sub>a0</sub> will be amplified by considering dilatancy. Considering both strain softening and dilatancy, when <i>σ</i><sub>a0</sub> is close to the tangential in-situ stress <i>σ</i><sub>t0</sub> or significantly greater than <i>σ</i><sub>t0</sub> (1.5 times), <i>σ</i><sub>a</sub> will be <i>σ</i><sub>2</sub> or <i>σ</i><sub>1</sub> at the initial yield, and then 3D plastic flow will occur. In the deformation prediction and support design of a deep tunnel, <i>σ</i><sub>a0</sub> should not be ignored, and the strain softening and dilatancy behavior of the surrounding rock should be accurately considered.https://www.mdpi.com/1996-1073/13/6/1502deep tunnelaxial in-situ stressstrain softeningdilatancyconstitutive model |
| spellingShingle | Kang Yi Zhenghe Liu Zhiguo Lu Junwen Zhang Shuangyong Dong Effect of Axial In-Situ Stress in Deep Tunnel Analysis Considering Strain Softening and Dilatancy Energies deep tunnel axial in-situ stress strain softening dilatancy constitutive model |
| title | Effect of Axial In-Situ Stress in Deep Tunnel Analysis Considering Strain Softening and Dilatancy |
| title_full | Effect of Axial In-Situ Stress in Deep Tunnel Analysis Considering Strain Softening and Dilatancy |
| title_fullStr | Effect of Axial In-Situ Stress in Deep Tunnel Analysis Considering Strain Softening and Dilatancy |
| title_full_unstemmed | Effect of Axial In-Situ Stress in Deep Tunnel Analysis Considering Strain Softening and Dilatancy |
| title_short | Effect of Axial In-Situ Stress in Deep Tunnel Analysis Considering Strain Softening and Dilatancy |
| title_sort | effect of axial in situ stress in deep tunnel analysis considering strain softening and dilatancy |
| topic | deep tunnel axial in-situ stress strain softening dilatancy constitutive model |
| url | https://www.mdpi.com/1996-1073/13/6/1502 |
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