Mechanical response of Q2 loess stratum surrounding a hydraulic tunnel under dry-wet cycles
Understanding the mechanical response of Q2 loess subjected to dry-wet cycles (DWCs) is the premise for the rational design of a hydraulic tunnel. Taking the Hanjiang-to-Weihe south line project in China as the research background, the microstructure evolution, strength degradation and compression c...
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Elsevier
2024-12-01
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| Series: | Journal of Rock Mechanics and Geotechnical Engineering |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S1674775524003354 |
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| author | Sen Peng Caihui Zhu Letian Zhai Haoding Xu Yubo Li Guohua Deng Miaomiao Ge Yuan Liu |
| author_facet | Sen Peng Caihui Zhu Letian Zhai Haoding Xu Yubo Li Guohua Deng Miaomiao Ge Yuan Liu |
| author_sort | Sen Peng |
| collection | DOAJ |
| description | Understanding the mechanical response of Q2 loess subjected to dry-wet cycles (DWCs) is the premise for the rational design of a hydraulic tunnel. Taking the Hanjiang-to-Weihe south line project in China as the research background, the microstructure evolution, strength degradation and compression characteristics of Q2 loess under different DWCs were investigated, and the fluid-solid coupling analysis of the hydraulic tunnel was carried out using the FLAC3D software. The amplification effect of tunnel surrounding soil pressure (SSP) and its influence on the long-term stability of the tunnel under different DWCs were obtained. The results showed that the pore microstructure parameters of the undisturbed and remolded loess basically tend to be stable after the number of DWCs exceeds 3. The porosity of Q2 loess is increased by 26%. The internal friction angle and cohesion of Q2 loess are decreased by 35% and 31%, respectively. The vertical strain of Q2 loess is increased by 55% after considering the DWCs. After the DWCs stabilized, the SSP ratio is increased between 10% and 25%. With the increase in buried depth of the tunnel, the SSP ratio is increased by 8%–10%. The SSP is reduced from 8% to 16% by the rise in groundwater level. As the number of DWCs increases and the burial depth of the tunnel decreases, the distribution of SSP becomes progressively more non-uniform. Based on the amplification factor and the modified compressive arch theory, the SSP distribution model of loess tunnel was proposed, which can be preliminarily applied to the design of supporting structures considering DWCs. |
| format | Article |
| id | doaj-art-509affe3449a431fb6321d65605362d3 |
| institution | Kabale University |
| issn | 1674-7755 |
| language | English |
| publishDate | 2024-12-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Rock Mechanics and Geotechnical Engineering |
| spelling | doaj-art-509affe3449a431fb6321d65605362d32024-12-11T05:55:59ZengElsevierJournal of Rock Mechanics and Geotechnical Engineering1674-77552024-12-01161249554970Mechanical response of Q2 loess stratum surrounding a hydraulic tunnel under dry-wet cyclesSen Peng0Caihui Zhu1Letian Zhai2Haoding Xu3Yubo Li4Guohua Deng5Miaomiao Ge6Yuan Liu7Institute of Geotechnical Engineering, Xi'an University of Technology, Xi'an, 710048, ChinaInstitute of Geotechnical Engineering, Xi'an University of Technology, Xi'an, 710048, China; State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, 710048, China; Corresponding author. State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, 710048, China.Institute of Geotechnical Engineering, Xi'an University of Technology, Xi'an, 710048, ChinaInstitute of Geotechnical Engineering, Xi'an University of Technology, Xi'an, 710048, ChinaChina Railway First Survey and Design Institute Group. Co., Ltd., Xi'an, 710043, ChinaInstitute of Geotechnical Engineering, Xi'an University of Technology, Xi'an, 710048, ChinaInstitute of Geotechnical Engineering, Wenzhou University, Wenzhou, 325035, ChinaShaanxi Institute of Water Resource and Electric Power Investigation and Design, Xi'an, 710001, ChinaUnderstanding the mechanical response of Q2 loess subjected to dry-wet cycles (DWCs) is the premise for the rational design of a hydraulic tunnel. Taking the Hanjiang-to-Weihe south line project in China as the research background, the microstructure evolution, strength degradation and compression characteristics of Q2 loess under different DWCs were investigated, and the fluid-solid coupling analysis of the hydraulic tunnel was carried out using the FLAC3D software. The amplification effect of tunnel surrounding soil pressure (SSP) and its influence on the long-term stability of the tunnel under different DWCs were obtained. The results showed that the pore microstructure parameters of the undisturbed and remolded loess basically tend to be stable after the number of DWCs exceeds 3. The porosity of Q2 loess is increased by 26%. The internal friction angle and cohesion of Q2 loess are decreased by 35% and 31%, respectively. The vertical strain of Q2 loess is increased by 55% after considering the DWCs. After the DWCs stabilized, the SSP ratio is increased between 10% and 25%. With the increase in buried depth of the tunnel, the SSP ratio is increased by 8%–10%. The SSP is reduced from 8% to 16% by the rise in groundwater level. As the number of DWCs increases and the burial depth of the tunnel decreases, the distribution of SSP becomes progressively more non-uniform. Based on the amplification factor and the modified compressive arch theory, the SSP distribution model of loess tunnel was proposed, which can be preliminarily applied to the design of supporting structures considering DWCs.http://www.sciencedirect.com/science/article/pii/S1674775524003354Q2 loessHydraulic tunnelSurrounding soil pressure (SSP)Dry-wet cycles (DWCs)Amplification effect |
| spellingShingle | Sen Peng Caihui Zhu Letian Zhai Haoding Xu Yubo Li Guohua Deng Miaomiao Ge Yuan Liu Mechanical response of Q2 loess stratum surrounding a hydraulic tunnel under dry-wet cycles Journal of Rock Mechanics and Geotechnical Engineering Q2 loess Hydraulic tunnel Surrounding soil pressure (SSP) Dry-wet cycles (DWCs) Amplification effect |
| title | Mechanical response of Q2 loess stratum surrounding a hydraulic tunnel under dry-wet cycles |
| title_full | Mechanical response of Q2 loess stratum surrounding a hydraulic tunnel under dry-wet cycles |
| title_fullStr | Mechanical response of Q2 loess stratum surrounding a hydraulic tunnel under dry-wet cycles |
| title_full_unstemmed | Mechanical response of Q2 loess stratum surrounding a hydraulic tunnel under dry-wet cycles |
| title_short | Mechanical response of Q2 loess stratum surrounding a hydraulic tunnel under dry-wet cycles |
| title_sort | mechanical response of q2 loess stratum surrounding a hydraulic tunnel under dry wet cycles |
| topic | Q2 loess Hydraulic tunnel Surrounding soil pressure (SSP) Dry-wet cycles (DWCs) Amplification effect |
| url | http://www.sciencedirect.com/science/article/pii/S1674775524003354 |
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