On September 11, the "CCCC Yutie No. 3" shield machine broke through the ground at Zhangjiawan Station, marking the successful breakthrough and reception of the right line of the section from Zhangjiawan Station to Wuliuyuan North Station on Chongqing Rail Transit Line 15.

It is understood that the section from Zhangjiawan Station to Wuliuyuan North Station is about 2.9 kilometers long. The domestically produced earth pressure balance shield machine "CCCC Yutie No. 3" undertook the right-line tunneling task. The section passes beneath the Liantan River three times, with a maximum longitudinal slope of -44.3‰. The continuous 500-ring shield tunneling was all carried out under the extreme curve condition of a 600-meter radius, making it one of the most difficult shield construction projects in China featuring a "large longitudinal slope and small curve radius," with a complex geological environment, high environmental protection requirements, and major technical challenges.

According to reports, in order to ensure the smooth completion of the project and solve the difficulties brought by the "large longitudinal slope and small curve radius" construction conditions, such as difficult muck transport and the risk of battery locomotive runaway and detachment, the project team implemented an intensive and penetrating management approach, invited industry experts to conduct multiple exploration and analysis of the shield construction site, and through meeting discussions, BIM model construction and testing, innovatively adopted a green and low-carbon belt conveyor muck removal device for rapid tunneling of metro shield tunnels. This improved muck removal efficiency, reduced the risk of runaway and detachment, made the whole process safer and more efficient, and laid a solid foundation for the smooth tunneling and breakthrough of the shield.

It is understood that after the project is completed, it will help improve Chongqing's rail transit network, enhance urban transportation efficiency, and provide Chongqing residents with more convenient, efficient, and comfortable travel services. Next, the project team will accelerate the shield machine station crossing and maintenance construction to ensure the smooth relaunch of the "CCCC Yutie No. 2" on the left line in the next stage.