On January 7, the shield tunneling machine No. 22396, independently developed and manufactured by CCCC Tianhe, successfully completed tunneling on the left line of the Dongqianhu North Station to Chengxin Road Station section of Ningbo Rail Transit Bid TJ7018, marking the achievement of dual-line breakthrough in this section. The tunneling task was completed in 4 months, with an outstanding record of a maximum of 600 rings advanced per month and 30 rings advanced in a single day.

The Dongqianhu North Station to Chengxin Road Station section has a total length of approximately 2.2 kilometers, and the longitudinal profile of the line generally presents a "V"-shaped slope. After departing from Dongqianhu North Station, the section passes alongside and beneath more than 20 buildings and structures before entering Chengxin Road Station, making it prone to problems such as ground settlement and lateral displacement. The tunnel crown cover depth in this section ranges from 10.14 to 21.82 m, and the minimum curve radius is 350 m. The strata are mainly silty clay, so the overall construction is technically demanding and carries high risks.

Ningbo is a coastal city with abundant groundwater. To ensure smooth shield tunneling and address the difficult and obstructive points, the shield cutterhead structure is designed in a spliced-plate 6-spoke form with an overall opening ratio of 45%. The single-side over-excavation exceeds the outer diameter of the front shield by only 10 mm, greatly reducing surface settlement during tunneling in silty clay strata, while also providing high strength against residual piles and portal openings. The main drive seals adopt, on both the inner and outer peripheries, one set of end-face polyurethane four-finger seals, two sets of rotating-surface polyurethane four-finger seals, and one set of rotating-surface rubber lip seals, capable of withstanding pressures of 10 bar. A shield tail clearance detection device is installed inside the tail shield to visualize the shield tail posture. The drive can provide a torque of more than 6400 kN.m to ensure smooth tunneling in clay and silty soil strata.