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| Application of the steel pipe pile arch cover method in large-span underground metro stations in weak and fragmented rock strata |
| WANG Lichuan1,2, HE Weiguo3, ZHANG Junru2,4*, WU Hongbin1,5, JIANG Xinqiang1,5, ZHANG Huijian2,4, WANG Wen6, HUANG Linxiang1,7
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1. China Railway 18th Bureau Group Co., Ltd., Tianjin 300222, China;
2. School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, Sichuan, China;
3. China Railway Sixth Survey and Design Institute Group Co., Ltd., Tianjin 300133, China;
4. Key Laboratory of Transportation Tunnel Engineering(Ministry of Education), Southwest Jiaotong University, Chengdu 610031, Sichuan, China;
5. The 4th Engineering Co., Ltd. of China Railway 18th Bureau Group, Tianjin 300350, China;
6. China Communications Third Highway Engineering Bureau Co., Ltd., Beijing 100010, China;
7. Municipal Engineering Co., Ltd. of China Railway 18th Bureau Group, Tianjin 300222, China |
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Abstract To address the issue that the traditional arch cover method relies on the support of hard underlying bedrock and is difficult to function in soft and broken strata, the steel pipe pile column arch cover method, which can effectively exert the efficacy of the arch cover method in soft and broken strata, was proposed based on the Jinjiang Road Station project of Guiyang Rail Transit Line S1, and its construction mechanical characteristics were studied. The research results showed that steel pipe piles were added below the arch cover foundation in the steel pipe pile column arch cover method. On the one hand, the steel pipe piles served as the foundation of the arch cover to improve its bearing capacity; on the other hand, when the lower half section of the station was excavated, they played the role of “advanced support”, constrained the deformation of the sidewall rock mass, and ensured the overall stability of the main structure. Compared with the traditional arch cover method, the steel pipe pile column arch cover method could effectively reduce stratum settlement, and the steel pipe piles shared the surrounding rock pressure, thereby reducing the maximum and minimum principal stresses of the initial support structure system. During the construction of the steel pipe pile column arch cover method, the construction of the arch cover part was the key to the method. After the construction of the arch cover and the station's initial support was completed, the maximum structural stress was located in the junction area between the sidewall and the inverted arch, which was the focus of attention during construction. The steel pipe pile column arch cover method, which uses a support system combining four pilot tunnel double-sidewall drift excavation, steel-reinforced concrete arch cover, and steel pipe pile columns, was successfully applied in the Jinjiang Road Station of Guiyang Rail Transit Line S1. Relying on the efficient coordination of the divided pilot tunnel construction mode, special trolley mold casting, and synchronous pouring technology, the construction period was shortened by approximately 10 months compared with the traditional arch cover method, the operation efficiency was significantly improved, and the impact on urban traffic was reduced.
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Published: 18 June 2025
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