On the morning of April 2, as the “Anshun” shield machine broke through the soil, the right line of the Renmin Park Station–Shangshagou Station shield tunnel section on Nanchang Metro Line 4 was successfully completed, laying the foundation for the key track-laying milestone of the entire line.

The Renmin Park Station–Shangshagou Station section starts from Shangshagou Station and arrives at Renmin Park Station for reception. The total length of the right line section is 1,094.307 m. Along the route, the section passes beneath more than 30 major risk sources, including the operating station of Line 3, the operating line of the Jiangbian freight yard, the dedicated railway line of the Xianshi Lake Grain Depot, rivers, a large number of buildings along the street, low-rise buildings in the old city reconstruction area, as well as numerous residential communities, municipal roads, and pipelines. In addition, the structures crossed beneath by the shield in this section cover three typical Nanchang strata: full-face rock, upper-soft lower-hard ground, and full-face sand. In particular, the shield passes beneath railways, buildings, and other structures over long distances under ultra-high confined water and complex upper-soft lower-hard strata, involving great construction difficulty and extremely high risk. During shield tunneling, mud cakes are prone to form on the cutterhead and in the soil chamber, causing abnormal tunneling parameters, aggravating cutter wear, and leading to construction risks such as blowouts, ground settlement, and water and sand ingress.

This section has complex geological conditions, passes beneath many structures, and is highly difficult. Since the shield launch of the right line section on December 6, 2020, the project team has made careful plans and, after 117 days, completed the construction milestone task 10 days ahead of the expected breakthrough schedule. During shield construction, China Railway No. 4 Engineering Group will, through measures such as optimizing muck conditioning parameters, formulating anti-blowout measures, balancing and controlling earth pressure, and secondary grouting during shield tunneling, conduct full-coverage ground-penetrating radar detection of both the excavated area and the area ahead not yet excavated to guide tunneling construction, secondary grouting reinforcement, and ground treatment operations. During tunneling, construction monitoring will be strengthened; when anomalies are detected, monitoring will be intensified and treatment measures will be formulated. At the same time, when passing beneath structures and pipelines, through rigorous organization, careful arrangement of construction procedures, and strict implementation of the leadership shift system, the project overcame construction technical difficulties such as water-rich conditions, large slopes, upper-soft lower-hard composite strata, and shield tunneling beneath structures, ensuring the successful completion of the construction and production tasks in this section and contributing to the construction of Nanchang Metro.

The project management branch required the project department to always regard “safety first” as the primary element of production, conduct in-depth research on key and difficult points such as passing beneath houses and rivers along the route, strengthen safety monitoring during construction, establish and improve the project department's shield production management system, hold daily coordination meetings, implement the daily shift handover system, analyze and sort out the day's shield construction tunneling parameters, shield posture, construction monitoring, and other conditions, earnestly summarize them, increase inspection efforts, effectively identify safety hazards, and ensure zero accidents in safe production.