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| Numerical simulation of shotcrete-anchor support for duplex arch tunnel in soft rock based on shear-slip line theory |
| ZUO Shuangying1, FU Li1, LI Haoyi1, LIU Bo1, PENG Muwen1, SONG Xiong2
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1. College of Resources and Environment Engineering, Guizhou University, Guiyang 550025, Guizhou, China;
2. Guangzhou Branch, China Railway First Group Co., Ltd., Guangzhou 511492, Guangdong, China |
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Abstract Excavation unloading of tunnels in soft weak surrounding rock forms a wedge-shaped plastic zone. Based on the shear-slip line theory proposed by RABCEWICZ L V et al, the supporting resistance provided by the anchor bar, shotcrete layer, steel mesh, and steel arch at the shear height was calculated and applied to the excavation outline in reverse. The numerical model of the double-arch tunnel of a section of Guiyang rail transit line 2# was built, and the construction scheme of middle guide hole-stairs method was used to simulate the excavation and support process, and the deformation and damage effect could be obtained, which were compared with the monitored data of the typical cross-section such as settlement, side wall convergence and roof arch settlement. The research results showed that the shotcrete-anchor support measures reduced the deformation of the surrounding rock, effectively relieved the stress concentration phenomenon after excavation, and the multi-arch effect of mid-partition wall was very obvious. The supporting structure and surrounding rock together layed an important role of common bearing circle, which may keep the whole tunnel stable.
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Published: 25 February 2021
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