On July 12, the Jinan Huanggang Road Yellow River Crossing Tunnel Project, invested and constructed by Jinan Urban Construction Group and built by China Railway 14th Bureau Group, marked another major milestone. The main drive of the "Shanhe" shield machine and the No. 4 trailer were successfully lowered into the shaft simultaneously, successfully activating the "heart" of the shield machine and bringing it one step closer to launch.

The Huanggang Road Yellow River Crossing Tunnel Project is the world's largest-diameter underwater shield tunnel. The project starts at Lanxiang Middle Road in the south and successively passes beneath Erhuan North Road, the Jinan-Guangzhou Expressway, the south bank levee, the Yellow River, the north bank levee, and the sedimentation basin of a Class I water source protection area, before emerging above ground where a toll station is provided; its terminus connects with the G309 interchange under construction. The project has a total length of about 5,755 meters, including a tunnel section of about 4,762 meters and a shield-driven section of about 3,290 meters. It adopts a single-tube double-deck layout, with a shield segment outer diameter of 16.8 meters. The road is classified as an urban arterial road with six lanes in both directions and a design speed of 60 km/h.

The main drive lowered into the shaft this time is the "heart" of the shield machine and its core component. Equipped with 16 sets of motors and 18 telescopic cylinders, it provides a continuous power source for the shield machine during excavation, performing the role of power conversion and output, and serves as the power output center for the shield machine's cutterhead. The No. 4 trailer lowered into the shaft is the rearmost of the shield machine's backup trailers. Carrying components such as the pipe changer, pipe-changing crane, and water/air hose reels, it is mainly responsible for extending the various pipelines of the shield machine.

The "Shanhe" shield machine used in the project is the largest-diameter slurry balance shield machine under construction, with a maximum excavation diameter of 17.5 meters, a total length of 163 meters, a weight of 5,200 tons, and a total installed power of 12,580 kW. It is equipped with 306 cutters of various types, of which 57 can be switched between disc cutters and toothed cutters, and the cutterhead opening ratio is 53%, maximally accommodating the complex strata encountered during excavation. The overall assembly of the shield machine has reached the world's advanced level.

As of now, the lowering and lifting tasks for the main drive, No. 1 trailer, bridge, No. 2 trailer, No. 4 trailer, and five shield body sections of the "Shanhe" shield machine have been successfully completed. Next, the segmented lifting operations for the cutterhead, No. 3 trailer, and the remaining shield body sections will be carried out, laying a solid foundation for the smooth launch of the "Shanhe."