On the morning of March 12, as the cutterhead rotated slowly, the "Longxing" TBM for the right-line section between Changchuan Road Station and Longchuan Road Station of the Phase II Project of Qingdao Metro Line 2, constructed by China Railway 24th Bureau Group, was successfully launched, marking the start of TBM mechanical excavation for Phase II of Line 2.

　　It is reported that the "Longxing" is a double-shield TBM with a total length of about 135 meters and a weight of 850 tons. It has 9 car frames, a maximum advance speed of up to 120 mm/min, and an average daily progress of about 7 meters. The equipment can adapt to the complex geological environment of the section. At the same time, the "Longxing" is also equipped with functions such as a muck weighing system and a shield tail clearance measurement system, which can monitor excavation parameters and muck output in real time, ensuring safe and orderly TBM construction.

　　The single-line Changlong section has a total length of 703 meters (after the "Longxing" completes excavation of the Changlong right-line section, it will be pushed empty through the mined-method tunnel section and Longchuan Road Station, and then continue construction of the Longbo section right line). Along the route, it passes through multiple major risk sources such as bridges, rivers, and buildings. Among them, the most difficult is the Changchuan Road Bridge, which must be undercrossed immediately after launch. At this location, the minimum vertical clearance between the tunnel crown and the bridge abutment is 2.55 meters, posing a high safety risk for excavation.

　　Under the guidance of the Qingdao Municipal Public Works Engineering Quality and Safety Supervision Station and the **Construction Branch of Qingdao Metro Group, the civil construction project management department of the Phase II Project of Qingdao Metro Line 2 of China Railway Construction Corporation took the lead in systematically sorting out the construction risks and key difficulties of the project with relevant units, held multiple special meetings on TBM launch, conducted detailed analysis and demonstration of the whole-process safety plan for TBM selection, design, assembly, commissioning, and excavation, and formulated feasible plans to ensure the safe and smooth launch and excavation of the "Longxing" TBM. The project team also used digital systems to strengthen excavation safety management and technical control, and established 2 TBM excavation teams, 1 equipment maintenance team, and 1 comprehensive support team, fully mobilizing the initiative and creativity of all operating personnel and providing strong guarantees for safe and efficient TBM section excavation.

　　The smooth launch of the "Longxing" TBM is another major milestone for the project following the topping-out of the main structure of Changchuan Road Station. The project team will continue to go all out, work hard, and press ahead with greater effort. Guided by practical results, with the "Three Persists" as the work philosophy and "building a world-class metro, team building, and support systems" as the systematic advancement path, they will comprehensively improve construction quality and efficiency, overcome difficulties, work together with one heart, and make every effort to advance Qingdao Metro construction.

　　The Phase II Project of Qingdao Metro Line 2 is an east-west major transportation artery passing through Licang District and connecting Laoshan District, and is also a backbone line in the east coast urban area. After completion, it will further radiate and drive the development of key areas such as eastern Licang District, the Academician Port Industrial Zone, and the Expo Park area, and is of great significance for improving the network structure of the east coast urban area and building a "Qingdao on Rails".