On September 8, on the section from the City Library Station to Sanhao Bridge Station of Shenyang Metro Line 6, the shield machine continuously cut through 26 Φ800 large-diameter retaining piles and passed beneath the existing City Library Station on Line 2, successfully achieving breakthrough on the left line of the section, marking this section as the first shield-driven section on Metro Line 6 to achieve breakthrough on both lines.

The City Library Station–Sanhao Bridge Station section is the first overlapping (stacked) section on a Shenyang Metro line to achieve breakthrough on both lines. Shenyang Metro Group and the Beijing Municipal Engineering Project Department conducted geophysical surveys of the ground and investigation and testing of structures in advance, formulated an optimal shield construction plan, and invited an authoritative expert group to conduct a "diagnosis" and carry out targeted design of the cutterhead. During the process, pile-grinding analysis meetings were held regularly to implement all measures. From the start of tunneling, excavation parameters were strictly controlled to reduce tool wear, ultimately achieving the goal of safely and smoothly crossing major and extraordinarily serious risks such as the overlapping section and pile grinding, and achieving breakthrough.

During construction, the twin shield tunnels advanced 2,383.405 meters in water-rich sandy gravel strata across the full face, with a fastest single shift of 12 rings and a fastest single day of 23 rings, successfully completing construction through a succession of major risk sources, including cutting 53 Φ800 retaining piles intruding into the tunnel envelope, passing beneath bridge piles at close range in an overlapping configuration, passing beneath an existing operating metro station and high-rise buildings, and crossing a 2,200×1,800 brick-and-stone drainage pipeline.