The east extension project of Rail Transit Line 21 has begun shield tunneling. On January 5, the upline shield of the Chuan-Sha intermediate ventilation shaft section (from Chuansha Road Station, formerly Liuchen Road Station, to the Chuan-Sha intermediate ventilation shaft) of Civil Works Section 1 of the Phase I east extension project of Line 21, invested by Shanghai Shentong Metro Construction Group Co., Ltd. and constructed by Shanghai Urban Construction Municipal Engineering (Group) Co., Ltd., was successfully launched. This is also the first shield machine to start tunneling in Shanghai rail transit in the New Year of 2025, marking that the shield tunneling construction of the Line 21 east extension project has entered a brand-new stage.

The upline section from Chuansha Road Station to the Chuan-Sha intermediate ventilation shaft launched this time is about 2.8 kilometers long, with a tunnel burial depth of 9.4 to 17.7 meters. The shield construction section passes through various complex geological conditions as well as multiple important buildings (structures) such as Tongcheng River Bridge and Malonggou Bridge, is adjacent to Bazao Port River, and runs eastward along Chuanliu Highway all the way to the receiving shaft.

Because there are multiple old pipelines within this tunnel section, with a long time span and distant years, existing data are lacking. In response, the construction team carried out surveys and visits on the pipeline conditions several times, compared data from multiple aspects such as pipeline ownership units, relocation units, construction units, and design units, and simulated the relative relationship between shield advancement and pipelines many times. Finally, multiple risky pipelines were identified and relocated, providing preliminary guarantees for the smooth launch of the shield.

To improve the precision and safety of shield construction and reduce the accumulation of deviations caused by human factors, the project team introduced an automatic axis correction system to build a solid "digital foundation" through refined management. High-precision sensors are used to monitor the axis status of the equipment in real time. During advancement, once an axis deviation from the preset standard is detected, the correction mechanism will be quickly activated to ensure that the shield axis posture always meets the design requirements, making tunnel construction more intelligent as well as more stable, safe, and efficient.

The east extension project of Line 21 is about 14 kilometers long. It runs eastward from Chuansha Road Station of the Phase I project, passes through the Shanghai East Railway Station hub, and ends at Pudong T3 Terminal. After the project is completed, it will break the situation of "no metro and difficult travel" in the surrounding area of Shiwan, Zhuqiao Town. At the same time, as an important part of the "Oriental Hub," Line 21 will further connect eastward to Shanghai East Railway Station and Pudong Airport, realize interconnection with the Airport Link Line, and promote the integration of the Oriental Hub into the Yangtze River Delta rail transit network.