Abstract
The Haizhu Bay Tunnel is the first extra-large diameter shield tunnel in the Guangzhou region. Its construction faces complex geological conditions, known as a "geological museum," making shield machine selection critical to project success. This study, based on this project, comprehensively considers multiple factors to determine the shield selection scheme and analyzes its application effectiveness. The project has a total length of 4.35 km, with a shield tunnel length of 2077 m and segment outer diameter of 14.5 m. It traverses strata including miscellaneous fill, sand layers, silty clay, and moderately to slightly weathered argillaceous siltstone, while also needing to pass beneath multiple waterways, fault zones, dense building clusters, and grind through numerous pile foundations, presenting extreme construction difficulty. During the shield selection process, the working principles, advantages, and disadvantages of Earth Pressure Balance (EPB) shields, slurry shields, Tunnel Boring Machines (TBMs), and dual-mode/multi-mode shields were compared. Considering factors such as stratum permeability coefficient, particle gradation, water pressure, and sensitivity of the surrounding environment, the slurry balance shield machine was ultimately selected. For cutter head selection, comparative tests were conducted: one tunnel used a Herrenknecht atmospheric cutter head shield machine, while the other used a CRCHI pressurized cutter head shield machine. Both shield machines underwent targeted designs, such as optimizing cutter head structure, rationally configuring cutting tools, and installing flushing and wear detection devices. Application results indicate that the west-line atmospheric cutter head shield machine achieved an average daily advance rate of 4.35 m/d and average monthly progress of 130.5 m/month; the east-line pressurized cutter head shield machine achieved an average daily advance rate of 5.31 m/d and average monthly progress of 159.4 m/month. In moderately and slightly weathered strata, the pressurized cutter head shield machine demonstrated significant advantages in excavation efficiency, with monthly progress 57 meters greater than that of the atmospheric cutter head shield machine. This project marks the first instance in China where shield machines with different cutter head types were employed on the same project in similar strata, with favorable construction outcomes that validate the rationality of the selection, providing valuable experience for shield machine selection and construction in similar projects.
Full Text
Selection and Application Effect Analysis of Ultra-Large Diameter Shield in Haizhu Bay Tunnel
Lu Yangyi, Zhang Haibin, Liu Jiazhi, Zhang Bo, Dai Changkang
Guangzhou Metro Engineering Consulting Co., Ltd., Guangzhou 510000, China
Abstract
The Haizhu Bay Tunnel represents Guangzhou's first ultra-large diameter shield tunnel project, confronting exceptionally complex geological conditions that have earned it the moniker "geological museum." Spanning a total length of 4.35 km, the shield-driven section extends 2,077 m with a segment outer diameter of 14.5 m. The tunnel traverses diverse strata including miscellaneous fill, sand layers, silty clay, and moderately to slightly weathered argillaceous siltstone. Compounding the challenges, the alignment must pass beneath multiple waterways, fault zones, and dense building clusters while grinding through numerous existing pile foundations, rendering construction extremely difficult. Given these circumstances, shield selection emerged as a critical determinant of project success.
This study systematically evaluated shield options by comparing the operating principles and merits of earth pressure balance (EPB) shields, slurry shields, rock tunnel boring machines (TBMs), and dual-mode/multi-mode shields. Comprehensive consideration of factors including formation permeability coefficients, particle gradation, water pressure, and environmental sensitivity ultimately led to the selection of a slurry balance shield machine. For cutterhead configuration, a comparative field test was implemented: the west tunnel employed a Herrenknecht atmospheric pressure cutterhead shield, while the east tunnel utilized a CRCHI pressure cutterhead shield. Both machines underwent targeted design optimizations, including refined cutterhead structures, rational tool arrangements, and integrated flushing and wear detection systems.
Application results demonstrated distinct performance profiles: the west-line atmospheric pressure cutterhead shield achieved average advance rates of 4.35 m/day and 130.5 m/month, whereas the east-line pressure cutterhead shield attained 5.31 m/day and 159.4 m/month. Notably, in moderately and slightly weathered strata, the pressure cutterhead shield exhibited a clear efficiency advantage, delivering 57 m more progress per month than its atmospheric pressure counterpart. This project marks the first instance in China where different cutterhead configurations were deployed simultaneously on the same project in similar geological conditions, achieving excellent outcomes that validate the rationality of the selection approach. The findings provide valuable experience and a reference framework for shield selection and construction in analogous engineering projects.
Keywords: Ultra-large diameter; Shield tunnel; Equipment selection; Cutterhead selection; Targeted design; Application effect