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Analysis of Gas Leakage Model and Influencing Factors of Shield Tunnel Segment Joint
(1. China Railway Siyuan Survey and Design Group Co., Ltd., Wuhan 430063; 2. National-Local Joint Engineering Research Center of Underwater Tunnelling Technology, Wuhan 430063; 3. School of Mechanical Science & Engineering, Huazhong University of Science and Technology, Wuhan 430074; 4. School of Mechanical Engineering, Hubei University of Technology, Wuhan 430068)
Abstract In a tunnel that is excavated through a stratum containing methane, the differences in the physical proper? ties of gas and liquid will result in different leakage characteristics, so it is necessary to investigate gas leakage mechanism at segment joints. First, from the perspective of leakage path, the segment joint gas leakage model is built, to derive the segment joint gas leakage rate formula. Then, the gasket numerical simulation model is built to analyze how gasket roughness and external air pressure will affect gas tightness. Finally, the multiple linear regression analysis of the simulation data is conducted to analyze the sensitivity of the factors, and the method for reducing segment joint gas leakage is proposed. As the results suggest, reducing the roughness will significantly inhibit gas leakage; when roughness is greater than 0.8 μm, the gas leakage rate increases significantly; with production cost considered, it is recommended to keep the gasket roughness within the range of 0.4~0.8 μm; as the external air pressure increases, the average contact stress between the contact surfaces does not increase continuously, and the height of leakage path does not change significantly as the positive pressure increases; the factors that affect gas leakage rate are roughness, external air pressure, dislocation, opening and hardness in descending order in terms of their degree of influence.
Abstract：
In a tunnel that is excavated through a stratum containing methane, the differences in the physical proper? ties of gas and liquid will result in different leakage characteristics, so it is necessary to investigate gas leakage mechanism at segment joints. First, from the perspective of leakage path, the segment joint gas leakage model is built, to derive the segment joint gas leakage rate formula. Then, the gasket numerical simulation model is built to analyze how gasket roughness and external air pressure will affect gas tightness. Finally, the multiple linear regression analysis of the simulation data is conducted to analyze the sensitivity of the factors, and the method for reducing segment joint gas leakage is proposed. As the results suggest, reducing the roughness will significantly inhibit gas leakage; when roughness is greater than 0.8 μm, the gas leakage rate increases significantly; with production cost considered, it is recommended to keep the gasket roughness within the range of 0.4~0.8 μm; as the external air pressure increases, the average contact stress between the contact surfaces does not increase continuously, and the height of leakage path does not change significantly as the positive pressure increases; the factors that affect gas leakage rate are roughness, external air pressure, dislocation, opening and hardness in descending order in terms of their degree of influence.
XIAO Mingqing1,
2 TANG Yuheng3 CHEN Junwei1,
2 ZHANG Chaoyong3 etc
.Analysis of Gas Leakage Model and Influencing Factors of Shield Tunnel Segment Joint[J] MODERN TUNNELLING TECHNOLOGY, 2023,V60(4): 6-13
2023, Vol. 60 