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| The minimum safe thickness of tunnel passing through fault fracture zone and its influencing factors |
| LI Pengfei1, LIU Hongxiang1, ZHAO Yong2, LIU Jianyou3, WANG Fan1
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1. Key Lab of Urban Security and Disaster Engineering of Ministry of Education, Beijing University of Technology, Beijing 100124, China;
2. Sichuan-Tibet Railway Co., Ltd., Chengdu 610043, Sichuan, China;
3. Railway Engineering Consulting Group Co., Ltd., Beijing 100020, China |
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Abstract When the tunnel crossed the fault fracture zone, it was easy to cause water and mud inrush, the minimum safe thickness of water resisting rock mass is an important guarantee to avoid water and mud inrush. The influence of fault dip angle and strike was considered, the lateral ground stress in the tunnel area adjacent to the faults was solved based on the theory of Terzaghi. The calculation model of mechanical characteristics analysis of water resisting rock mass for tunnel crossing fault was established, and the calculation formula of the minimum safe thickness of water inrush prevention was obtained. The formula was used to calculate the minimum safe thickness in Qilianshan Tunnel, and compared with the actual thickness, which proved the reliability and feasibility of the theoretical solution. The influence factors of the minimum safe thickness were analysed. The results showed that the minimum safe thickness of water inrush prevention increased with the increase of tunnel radius, water head height, fault width and fault strike angle, increased with the decrease of fault dip angle, and decreased with the increase of friction angle and cohesion in water resisting rock mass.
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Received: 07 July 2020
Published: 20 September 2020
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