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Study on the Support Structure Design of Spatially Small-spaced Four-tube Section of He′ao Tunnel
(1. China Railway Siyuan Survey and Design Institute Group Co., Ltd., Wuhan 430063; 2. National-Local Joint Engineering Research Center of Underwater Tunnelling Technology, Wuhan 430063)
Abstract The quantified design of parameters and safety analysis of the support structure of a spatially smallspaced multi-tube tunnel are the major difficulties in the current design. In view of the design of the spatially smallspaced four-tube section of He′ao Tunnel on the Bao′an International Airport-He′ao Expressway of Shenzhen, the total safety factor method is adopted to conduct the research and comparison of excavation and support modes of four tubes, excavation sequences of various tubes and support parameters. The load-structure method specified in the tunnel design code, incremental method and ground-structure method are used to compare and calculate the safety coefficients of the support structure. The conclusions are as follows: (1) the design method of spatially small-spaced multi-tube tunnel is put forward based on the principle of total safety factor method; (2) according to the total safety factor method, the spatially small-spaced four-tube section of He'ao Tunnel shall adopt the excavation and support mode that "the secondary lining of the first tube should be fully completed before excavation of the next tunnel tube", and following the excavation sequence during construction: Tube 1 → Tube 2 →Tube 3 → Tube 4; and (3) the tunnel code specified load-structure method, incremental method and ground-structure method cannot get the total bearing safety coefficient of the structure, but it can reflect the safety of some support structure to some extent possible.
Abstract：
The quantified design of parameters and safety analysis of the support structure of a spatially smallspaced multi-tube tunnel are the major difficulties in the current design. In view of the design of the spatially smallspaced four-tube section of He′ao Tunnel on the Bao′an International Airport-He′ao Expressway of Shenzhen, the total safety factor method is adopted to conduct the research and comparison of excavation and support modes of four tubes, excavation sequences of various tubes and support parameters. The load-structure method specified in the tunnel design code, incremental method and ground-structure method are used to compare and calculate the safety coefficients of the support structure. The conclusions are as follows: (1) the design method of spatially small-spaced multi-tube tunnel is put forward based on the principle of total safety factor method; (2) according to the total safety factor method, the spatially small-spaced four-tube section of He'ao Tunnel shall adopt the excavation and support mode that "the secondary lining of the first tube should be fully completed before excavation of the next tunnel tube", and following the excavation sequence during construction: Tube 1 → Tube 2 →Tube 3 → Tube 4; and (3) the tunnel code specified load-structure method, incremental method and ground-structure method cannot get the total bearing safety coefficient of the structure, but it can reflect the safety of some support structure to some extent possible.
XIAO Mingqing1,
2 XU Chen1,
2 ZHENG Qiang1 etc
.Study on the Support Structure Design of Spatially Small-spaced Four-tube Section of He′ao Tunnel[J] MODERN TUNNELLING TECHNOLOGY, 2022,V59(2): 1-10
2022, Vol. 59 