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| Active support design and intersection construction technology for large-span underground excavation station in hard rock stratum |
| WANG Qinghan1, ZHAO Jizeng2, TIAN Ning1
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1. Jinan Design Institute, Railway Engineering Consulting Group Co., Ltd., Jinan 250022, Shandong, China;
2. Qingdao Metro Co., Ltd., Qingdao 266000, Shandong, China |
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Abstract According to the hard rock stratum of Qingdao subway tunnel, the prestressed anchor rod, instead of the traditional hollow grouting anchor rod, was used for active support of the arch and side wall of the underground excavation station. The grid spacing and shotcrete thickness was optimized. The excavation of large section tunnel in grade Ⅳ surrounding rock in step method was realized. The numerical analysis and monitoring measurement results showed that the support scheme was safe and feasible. The construction methods of the underground excavation station and the air duct was compared and analyzed. Combined with the active support technology, the technology of construction through air duct was optimized, the upper half section of the duct was expanded and section steel frame supporting conditions was reserved. The construction in step method was realized, with clear force conversion, which was safe, efficient and convenient.
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Received: 24 April 2021
Published: 20 June 2021
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