On January 9, the first shield tunneling machine for the section between Hefei Road Station and Chuzhou Road Station of Qingdao Metro Line 5, named "Kaituo" (Pioneer), set off from Hefei Road Station, officially launching its journey of "pioneering." This is the first shield machine to start tunneling in Qingdao Metro this year.

The cutterhead of "Kaituo" is hoisted and lowered into the shaft

"Kaituo" has a total length of 89 meters, an excavation diameter of nearly 7 meters, and a total weight of about 550 tons. It is an earth pressure balance shield machine and adopts a sealed steel sleeve for launching. This is also the first shield machine on Qingdao Metro Line 5 to use the steel sleeve launching technique. The steel sleeve construction process uses four custom-made steel segments connected with high-strength bolts to form a closed box that can fully enclose the shield machine, ensuring sealing during launch, avoiding problems such as ground collapse and water ingress, and improving construction safety. At the same time, it can greatly reduce the impact of noise and vibration on the surrounding environment and lower energy consumption during construction, making it suitable for various geological conditions and complex environments.

The tunneling section is the right line from Hefei Road Station to Chuzhou Road Station, with a total length of 558.32 meters and a maximum burial depth of 14.5 meters. The geology of the tunnel in this section is complex, groundwater is abundant, and the reinforcement area at the launching end of the section is far smaller than the conventional reinforcement range. To ensure orderly shield tunneling, the project department optimized the shield machine selection, organized expert demonstrations, and prepared special construction plans. Under the help and guidance of Qingdao Metro Group and the CREC Development Project Management Department, China Railway No. 4 Engineering Group completed the assembly and commissioning of the shield machine in only 7 days and completed condition verification, acceptance, and related work 40 days ahead of schedule. At the same time, digital and intelligent means were used to strengthen tunneling safety management and technical control, providing strong guarantees for safe and stable construction operations.

To ensure the smooth construction of shield tunneling in the section, China Railway No. 4 Engineering Group equipped an experienced management and operation team and set up two professional shield tunneling work teams. It adhered to the three-stage approach of "establishing upon entry, operating only after meeting standards, and creating demonstrations throughout the process," emphasizing that "project management should sink into and integrate with the teams, and the teams should improve themselves to match project management," thereby ensuring high-quality and sustainable team development.

Qingdao Metro Line 5 is located in Qingdao's core urban area, starting at Maidao Station and ending at Yunling Road Station. It is a "C"-shaped line connecting the rail transit network of Qingdao's central area, covering the three districts of Shinan, Shibei, and Laoshan. The line is about 32.6 kilometers long and has 27 stations in total, including 12 transfer stations, linking with 8 metro lines. After the line is completed, it will further enhance the networked operation function of the metro in the main urban area. At present, 4 stations along the entire line have been topped out, and 11 mechanical tunneling equipment units have been launched, accounting for 50% of the total equipment on the line.