Study on the Synergistic Effect of Primary Support and Surrounding Rock of Large Buried Depth Tunnel in Soft and Fractured Strata
The soft and fractured strata can cause significant deformation of surrounding rock during tunnel excavation. This study analyzes field monitoring test results and compares numerical simulations from the third bid project of the Dali I section construction within the water diversion project in centr...
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| Format: | Article |
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MDPI AG
2024-02-01
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| Series: | Applied Sciences |
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| Online Access: | https://www.mdpi.com/2076-3417/14/5/2028 |
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| author | Tianyi Wang Haining Liu Minglei Kang Benchao Zhao Jixian Shen Yingchun Li Yandong Yang |
| author_facet | Tianyi Wang Haining Liu Minglei Kang Benchao Zhao Jixian Shen Yingchun Li Yandong Yang |
| author_sort | Tianyi Wang |
| collection | DOAJ |
| description | The soft and fractured strata can cause significant deformation of surrounding rock during tunnel excavation. This study analyzes field monitoring test results and compares numerical simulations from the third bid project of the Dali I section construction within the water diversion project in central Yunnan to address the issue of significant deformation following tunnel excavation in soft and fractured strata. It proposes an optimized support scheme consisting of a densified steel arch and enhanced initial support strength and stiffness. In addition, the research investigates support effectiveness considering varying support strengths and steel arch ring spacing. The study findings indicated the following: (1) The tunnel traverses soft and fractured strata, causing unevenly distributed vertical convergence deformation around the cavern. The maximum settlement occurs at the crown, showing pronounced nonlinearity. (2) The maximum stress in the steel arch is concentrated at the arch crown, measuring −19.02 MPa. The arch remains compressed, with stress decreasing from the crown to the waist. (3) The axial force in the anchor bolt reduces from the crown to the arch’s waist on both sides. As the depth of the rock mass increases, the axial force in each anchor bolt decreases and the tension state is maintained. The maximum axial force reaches 46.57 kN. (4) The maximum displacement decreases from 4.21 to 0.15 cm after the optimized support structure is implemented, demonstrating the optimization scheme’s effectiveness. Future constructions can refer to this scheme and make necessary adjustments based on various terrain conditions to ensure safety. |
| first_indexed | 2024-04-25T00:34:35Z |
| format | Article |
| id | doaj.art-a1ab6a14013f419996a9182ad761e135 |
| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-04-25T00:34:35Z |
| publishDate | 2024-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Applied Sciences |
| spelling | doaj.art-a1ab6a14013f419996a9182ad761e1352024-03-12T16:39:52ZengMDPI AGApplied Sciences2076-34172024-02-01145202810.3390/app14052028Study on the Synergistic Effect of Primary Support and Surrounding Rock of Large Buried Depth Tunnel in Soft and Fractured StrataTianyi Wang0Haining Liu1Minglei Kang2Benchao Zhao3Jixian Shen4Yingchun Li5Yandong Yang6College of Geosciences and Engeering, North China University of Water Resources and Electric Power, Zhengzhou 450046, ChinaCollege of Geosciences and Engeering, North China University of Water Resources and Electric Power, Zhengzhou 450046, ChinaHenan Haihe River Basin Water Resources Affairs Center, Xinxiang 453002, ChinaHenan Haihe River Basin Water Resources Affairs Center, Xinxiang 453002, ChinaHenan Water Conservancy Investment Group Co., Ltd., Zhengzhou 450002, ChinaHenan Water Conservancy Investment Group Co., Ltd., Zhengzhou 450002, ChinaState Key Laboratory of Shield Machine and Boring Technology, Zhengzhou 450001, ChinaThe soft and fractured strata can cause significant deformation of surrounding rock during tunnel excavation. This study analyzes field monitoring test results and compares numerical simulations from the third bid project of the Dali I section construction within the water diversion project in central Yunnan to address the issue of significant deformation following tunnel excavation in soft and fractured strata. It proposes an optimized support scheme consisting of a densified steel arch and enhanced initial support strength and stiffness. In addition, the research investigates support effectiveness considering varying support strengths and steel arch ring spacing. The study findings indicated the following: (1) The tunnel traverses soft and fractured strata, causing unevenly distributed vertical convergence deformation around the cavern. The maximum settlement occurs at the crown, showing pronounced nonlinearity. (2) The maximum stress in the steel arch is concentrated at the arch crown, measuring −19.02 MPa. The arch remains compressed, with stress decreasing from the crown to the waist. (3) The axial force in the anchor bolt reduces from the crown to the arch’s waist on both sides. As the depth of the rock mass increases, the axial force in each anchor bolt decreases and the tension state is maintained. The maximum axial force reaches 46.57 kN. (4) The maximum displacement decreases from 4.21 to 0.15 cm after the optimized support structure is implemented, demonstrating the optimization scheme’s effectiveness. Future constructions can refer to this scheme and make necessary adjustments based on various terrain conditions to ensure safety.https://www.mdpi.com/2076-3417/14/5/2028diversion tunnelsoftly fractured stratasurrounding rock deformation monitoringsteel arch stressnumerical simulation |
| spellingShingle | Tianyi Wang Haining Liu Minglei Kang Benchao Zhao Jixian Shen Yingchun Li Yandong Yang Study on the Synergistic Effect of Primary Support and Surrounding Rock of Large Buried Depth Tunnel in Soft and Fractured Strata Applied Sciences diversion tunnel softly fractured strata surrounding rock deformation monitoring steel arch stress numerical simulation |
| title | Study on the Synergistic Effect of Primary Support and Surrounding Rock of Large Buried Depth Tunnel in Soft and Fractured Strata |
| title_full | Study on the Synergistic Effect of Primary Support and Surrounding Rock of Large Buried Depth Tunnel in Soft and Fractured Strata |
| title_fullStr | Study on the Synergistic Effect of Primary Support and Surrounding Rock of Large Buried Depth Tunnel in Soft and Fractured Strata |
| title_full_unstemmed | Study on the Synergistic Effect of Primary Support and Surrounding Rock of Large Buried Depth Tunnel in Soft and Fractured Strata |
| title_short | Study on the Synergistic Effect of Primary Support and Surrounding Rock of Large Buried Depth Tunnel in Soft and Fractured Strata |
| title_sort | study on the synergistic effect of primary support and surrounding rock of large buried depth tunnel in soft and fractured strata |
| topic | diversion tunnel softly fractured strata surrounding rock deformation monitoring steel arch stress numerical simulation |
| url | https://www.mdpi.com/2076-3417/14/5/2028 |
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