Recently, the shield tunneling section from Hechuan Road Station to Hanchuan Road Station (hereinafter referred to as the "He-Han Section") of the Phase II Project of Qingdao Metro Line 2 achieved right-line tunnel breakthrough. This makes it the **work area in the entire Phase II Project of Qingdao Metro Line 2 to successfully complete shield construction, and also the **work area in the Phase III Project of Qingdao Metro to successfully conclude the shield construction process.

The double-line He-Han Section has a total length of 1,135.1 meters. Two shield machines were deployed simultaneously for excavation of the left and right lines. The "Liu Shuai" and "Qi Jie" shield machines both launched from Hechuan Road Station, bored eastward, and were received at Hanchuan Road Station.

As of now, the main structure construction of Hechuan Road Station and Fo'erya Station of the Phase II Project of Qingdao Metro Line 2 has been completed. Both the section from Fo'erya Station to Hechuan Road Station (the "Fo-He Section") and the section from Hechuan Road Station to Hanchuan Road Station (the "He-Han Section") have achieved double-line breakthrough, consistently maintaining a "bellwether" position across the entire line. Since mobilization, the project has closely centered on the target requirements of safety, quality, schedule, and management, meticulously planned construction organization, scientifically coordinated resource allocation, and infused refined management into every aspect of construction. It has successively achieved important project milestones including the **opening of the traffic diversion road, the **entry into enclosure structure construction, and the **completion of excavation condition acceptance.

The He-Han Section features dense buildings, hard rock, and strongly developed geological karst. The shield tunnel has a total length of 567.55 meters. During construction, the project faced the challenge of frequently crossing upper-soft and lower-hard strata over long distances. The section tunnel lies beneath roads with densely distributed surrounding pipelines, imposing stricter requirements on surface settlement control. Construction also had to overcome difficulties such as work stoppages during the zhongkao and gaokao examinations.

During shield tunneling, one technical staff member was assigned inside the tunnel to monitor segment assembly and grouting on-machine, consolidating routine process management. For the quality of formed segments, the 10-ring挂牌 inspection and acceptance system by quality inspectors was strictly implemented. In addition, the project team carried out strict monitoring, re-measuring the axis of the formed tunnel once every 10 rings, with a 5-ring overlap required between successive re-measurements, so as to adjust the tunneling attitude and grouting parameters in a timely manner. Testing work also systematically conducted comparative selection of synchronous grouting mix proportions, with slurry quality sampled and inspected every 5 rings, dynamically tracking parameters such as pumpability and consistency to ensure project quality.

In response to the construction difficulties of the section, the shield machine was equipped with multiple intelligent innovative technologies—a newly added advanced geological prediction system to effectively detect unfavorable geology, achieving early detection and early warning and fully safeguarding safety during tunneling; and, given the complex and variable stratum geology, the shield machine was also equipped with three intelligent systems including a new-type grout stop plate, a shield gap measurement system with accuracy of less than 5 millimeters, and a real-time muck weighing system, which can effectively control ground settlement and enhance project quality through multiple measures. Through test sections, the expert team summarized the tunneling parameters for passing beneath fracture zones and heterogeneous composite strata of uneven hardness, and during construction derived control measures for segment uplift in granite strata, enriching shield construction techniques and methods and laying a solid foundation for ensuring efficient and safe shield construction.

It is reported that the Phase II Project of Qingdao Metro Line 2 has a total length of 8.9 kilometers, comprising 8 stations and 10 sections. It is a major transportation artery connecting eastern Licang with the central urban area of Licun, and is of great significance for improving the network structure of the east-bank urban area and driving the planned development of eastern Licang District and the Expo Park area. Once put into operation, it will greatly improve the traffic environment along the line and citizens' travel conditions.