On September 30, the National Key R&D Program project "Key Technologies and Equipment for Green Construction of Integrated Station-Tunnel with Variable-Diameter Shield in Urban Rail Transit," led by Guangzhou Metro Group with the participation of China Railway Engineering Equipment Group and other units, achieved major progress. The project team independently developed the world's first in-situ continuous large-scale variable-diameter shield tunneling machine, "Variable Diameter No. 1," which successfully rolled off the production line in Shunde District, Foshan City. This achievement not only fills the gap in "in-situ, continuous, large-scale variable-diameter" shield equipment in the rail transit field, but also marks that urban rail transit construction has officially entered a new green development stage of "small excavation footprint, low impact, and minimal disturbance."

Leaders attending the roll-off event included Liu Zhicheng, Party Secretary and Chairman of Guangzhou Metro Group Co., Ltd.; Wang Hui, Deputy General Manager of Guangzhou Metro Group Co., Ltd.; Gong Yiwei, Party Secretary and Chairman of Guangdong Huasui Construction Group Co., Ltd.; Zhuo Puzhou, General Manager of China Railway Hi-tech Industry Corporation; Gong Jian, Chief Engineer of Shanghai Construction Group Co., Ltd.; Li Liping, Dean of the Qilu Transportation College of Shandong University; and Jia Lianhui, Chief Engineer of China Railway Engineering Equipment Group.

▲ Jointly pushing the equipment roll-off启动杆

Urban rail transit station construction is usually dominated by open-cut and mined methods, with interval tunnels built independently. This separated construction process causes significant environmental disturbance, low resource intensification, and long construction periods. These pain points are particularly prominent in urban core areas with limited space and sensitive environments.

To break the constraints of traditional construction models, the "Variable Diameter No. 1" shield tunneling machine rolled off the line this time can freely adjust its diameter, breaking through the inherent model of "one diameter for life" of traditional shield machines, and has a flexible variable-diameter excavation capability of 8.83 meters to 12.45 meters. The equipment innovatively realizes "one station, two tunnels, continuous formation" construction: the shield machine first excavates the interval tunnel with a small diameter, and after reaching the station position, it performs in-situ "diameter expansion" to excavate a wider station platform-level tunnel. After completing the station section construction, it then "shrinks" its diameter and continues tunneling toward the next interval, without the need for midway machine disassembly or additional working shafts. This solves the worldwide challenge of integrated construction of rail transit interval tunnels and station tunnels in one go.

The successful development of the "Variable Diameter No. 1" shield tunneling machine is a major breakthrough in China's tunnel engineering equipment field. It not only greatly improves construction efficiency and reduces surrounding impacts and overall costs, but also provides a green, safe, intensive, and efficient new construction solution for global underground engineering, with significant economic benefits and broad promotion prospects. The successful roll-off of this equipment marks a key step forward for China in the field of green and intelligent rail transit construction.