Construction Risk Control of Large-Section, Small-Spacing Rectangular Pipe-Jacking Metro Stations: A Case Study of Haibang Metro Station in Guangzhou, China

Ensuring construction safety for a metro project in an urban area, particularly when crossing beneath high-pressure oil and natural gas pipelines in water-rich, weak strata, requires robust risk control strategies. The authors examine risk control measures for the construction of large-section, small-spacing rectangular pipe-jacking metro stations. Key measures, including pre-reinforcement techniques, pipe-jacking parameters, and closely adjacent construction methods, are implemented. A slurry-balanced rectangular pipe-jacking machine featuring a central large cutterhead, two rectangular side cutterheads, and an excavation rate of up to 95% is selected. Reinforcement strategies include ground reinforcement at the jacking shaft end, horizontal reinforcement at the receiving shaft end, and reserved reinforcement holes for interconnection channels within the pipe-jacking section. These measures ensure that critical parameters such as total jacking thrust, cutterhead torque, slurry chamber pressure, and jacking speed, remain within specified ranges. By employing jacking posture control technology, enhancing synchronous and secondary grouting, and increasing the longitudinal rigidity of pipe segments through posttensioning of prestressed steel strands, closely adjacent construction is successfully executed. Monitoring data analysis indicates the following: (1) During excavation of the left and right lines, surface and pipeline settlements are controlled within - 7.20 to 0.76 mm and - 5.49 to 3.51 mm, respectively. (2) During closely adjacent construction of the right line, surface and pipeline settlements are maintained within -3.64 to 3.61 mm and -1.45 to 2.92 mm, respectively. © 2025 Editorial Office of Tunnel Construction. All rights reserved.