On August 7, with the roar of the shield machine breaking through the soil, the left-line shield tunneling of the Sixin Middle Road Station–Fangcao Road Station section in Work Area 1 of Bid Section 2 of the Jiangbei Segment was successfully completed. With this, the shield-driven section has achieved full double-line breakthrough, marking that the project has secured phased results in its vigorous push forward and laying a solid foundation for accomplishing the year's goals.

The left line of the Si–Fang section has a total length of 1,106.1 meters, with a small curve radius of 360 meters and a maximum longitudinal slope of 24‰. The shield construction attitude, axis control, and segment assembly quality are relatively difficult to control, making it easy to cause staggering and cracking of the assembled shield segments. In addition, the strata within the tunneling section are uneven in hardness and softness, and the undercrossed buildings are relatively dense, making the construction environment more complex.

To ensure construction safety throughout the shield tunneling process, the project department fully drew on the tunneling experience of the right line, summarized and analyzed the problems existing in the right-line shield tunneling process, and formed a list of countermeasures to prevent recurrence of similar problems. At the same time, it dynamically tracked construction progress, scientifically avoided and reduced risks, and ensured the advancement efficiency of the left line. During the assembly of the shield machine, each component was carefully inspected and configured, and various parameters such as shield thrust and cutterhead rotation speed were debugged multiple times to ensure the equipment was in optimal condition. Safe and civilized construction was implemented, with pre-shift briefings and post-shift summaries adhered to, and dedicated personnel assigned to on-site inspection and control; any non-compliance with construction requirements was stopped and corrected immediately to ensure safe production.