On October 1, with the steady rotation of the cutterhead of the "Hongxing No. 2" shield machine, the Qingdao Metro Line 6 Phase II project reached another milestone: the left-line shield machine for the Hongshulin Station–Xintun Road Station section (hereinafter referred to as the Hong-Xin section) officially began excavation, marking the full launch of dual-line shield tunneling in this section.

The successful launch of "Hongxing No. 2" is another major advance following the successful launch in March this year of the "Hongxing" micro-slurry + earth pressure dual-mode shield machine on the right line of the same section. The Hong-Xin section passes beneath two river channels and runs along the south side of Binhai Avenue. The left line of the shield tunnel section has a total length of 1,298.977 m and involves four types of unfavorable geology: unevenly weathered rock, water-rich sand layers, soft-hard uneven strata, and fill/reclamation land, posing extremely high construction risks.

To ensure the smooth launch of the left-line shield, the project team established a dedicated task force, overcame numerous difficulties such as narrow working faces and complex terrain, drew on the successful experience of the right-line shield launch, and cleverly applied the strategy of "seizing every opportunity and creating opportunities where none exist" to comprehensively review construction risks and difficulties. The team held multiple special meetings and coordinated closely with equipment manufacturers, formulated a detailed pre-launch task list, and implemented each item one by one. It used information technology for all-round monitoring and measurement, achieved dynamic management of construction and equipment through a remote video monitoring system, adopted a micro-slurry + earth pressure dual-mode shield machine for tunnel excavation, and adjusted construction parameters and grouting volumes in real time to ensure optimal conditions were reached in a short period. In this way, it safely and efficiently completed key procedures such as preparations for construction in unfavorable geology, shield machine hoisting, and equipment commissioning and launch, achieving the smooth launch of the left-line shield.