On the morning of the 22nd, as the shield machine's cutterhead began to rotate slowly, the first shield machine for Tianjin Rail Transit Line Z4, "TEDA," was successfully launched, marking the full entry of Line Z4 into the shield tunneling construction phase.

The Phase I project of Tianjin Rail Transit Line Z4 starts from the planned Central New City in the south and extends north to Hangu District, with a total length of 43.7 kilometers and 24 stations. It is a backbone line connecting the northern and southern areas of the Binhai New Area with the core area. This shield tunneling section is located between Jinlin Dao Station and Dagu Shipyard Station, with a total length of 1,024 meters. It is the first shield tunneling project in the Binhai New Area to pass beneath the Haihe River and also the longest shield-driven section crossing a river in the city. The shield machine will successively pass beneath building clusters, the Haihe River, and major urban arterial roads. The section features an intricate groundwater system and complex geological conditions, making construction highly challenging.

In response to the major and difficult issues during construction, the project team of China Construction Eighth Engineering Division conducted thorough research and design on the cutterhead structure, cutter types, sealing forms, articulation forms, and other aspects, and tailor-made the "TEDA" shield machine. This domestically developed shield machine has a total length of 85 meters and weighs about 550 tons. It adopts a six-spoke composite heavy-duty cutterhead with sufficient stiffness and strength, and with the design of a 3.4-meter large-diameter main bearing, it increases the rated torque of the cutterhead and improves impact resistance.