Recently, with the "Changxing" TBM cutterhead breaking through, the left line of the Changchuan Road Station–Longchuan Road Station section (hereinafter referred to as the Changlong section) of the Phase II project of Qingdao Metro Line 2, in which the Rail Transit Branch of China Railway 24th Bureau Group participated in construction, was successfully holed through, and tunnel construction on the project has entered a stage of comprehensive acceleration.

The left line of the Changlong section is about 775 m long, with a tunnel depth of 15–25 m. It generally passes through slightly weathered strata, with locally developed geological compression zones, and the geological environment of the section is relatively complex. Along the route, the line crosses many major risk sources such as bridges, rivers and buildings. Since the "Changxing" TBM was launched in April 2024, the project team has taken the initiative rather than waiting: First, it has adhered to digital leadership. The TBM equipment is equipped with a muck weighing system and a shield tail clearance measurement system to grasp the tunneling parameters and muck output in real time; a TBM digital overview system has been established to dynamically optimize tunneling parameters through the integrated application of multiple models, multiple perspectives and multiple data, ensuring safe and efficient TBM tunneling. Second, it has taken team building as a key lever. Treating work teams as the basic units on the construction front line, it has strengthened team management, improved team skills and stimulated team vitality. This has driven the teams to actively carry out "five small" innovation activities. The "TBM Left Line Tunneling Team" installed buffer rubber pads on the shoe panels of the auxiliary thrust jacks, avoiding rigid contact between the shoes and the segment rings and effectively reducing the segment damage rate.

Next, the project department will continue to strictly control safety and quality, carry out refined management and orderly organization, and make good preparations for the in-tunnel rotation and shaft lifting of the TBM equipment, striving to achieve full-line holing-through of the project as soon as possible.