On June 23, as the cutterhead of the "Yihang No. 11" shield machine broke through the soil, it marked the right-line breakthrough of the Dafeng section (referred to as the "Dafeng Section") of the interval from Dajian Station to Daguhe Museum Station on the Qingdao Metro Line 8 Branch, constructed by the company. This interval is the third single-line shield-driven tunnel section to achieve breakthrough on the entire line.

The Dafeng Section is constructed using the shield tunneling method. The right line of the section has a total length of 2,094 meters, with a minimum turning radius of 800 meters. It passes through slightly weathered rhyolitic tuff, andesite, sandstone, and other rock types, with a maximum rock strength of 133 MPa. The geology is complex, and the alignment crosses multiple major environmental risk sources, including the Jinan-Qingdao High-Speed Railway, the Airport Expressway, and the existing Metro Line 8, placing high demands on construction precision and stable shield tunneling.

The project department strengthened process control, including optimization of shield machine selection, adjusted the width of the shield disc cutter edge to enhance the machine's rock-breaking capability; applied split-launch technology to overcome the "inherent deficiency" of Dajian Station having no shield launch shaft; refined the identification of risk sources, formulated specialized construction plans and emergency response plans, and advanced refined on-site management through standardized team building, ensuring the smooth launch of the shield machine.

To ensure smooth shield tunneling and reception, the project department adhered to the leadership shift duty and side-station supervision systems, while ensuring safe and stable shield tunneling through measures such as informatized monitoring and data analysis; actively carried out technical research on segment assembly, muck conditioning, tunneling parameters, and simultaneous grouting to ensure that segment assembly quality meets specification requirements; shortened process transition times and accelerated construction progress under the premise of ensuring safety and quality, successively overcoming difficulties such as winter construction, passing beneath multiple risk sources, and muck removal during the flood season, with the maximum monthly advance reaching 330 meters; strengthened surface and in-tunnel monitoring, promptly adjusted the shield machine attitude according to geological conditions, and ultimately achieved precise single-line breakthrough of the interval tunnel.