On January 6, as the cutterhead of the "Yellow River" shield machine broke through and successfully reached the receiving shaft, the west-line tunnel of the Jinan Yellow River Jiluo Road North Extension Project—invested in and constructed by Jinan Urban Construction Group and built by China Railway 14th Bureau Group—was completed. This marks important progress in the construction of the major transportation artery of the Jinan Start-up Area for Growth Drivers Transformation, and has accumulated valuable experience for super-large-diameter shield tunnels crossing medium and large reservoirs.

The Jinan Yellow River Jiluo Road North Extension Project is an important transportation project for thoroughly implementing the major national strategy of ecological protection and high-quality development of the Yellow River Basin, and is also an important link connecting Jinan's main urban area with the Start-up Area for Growth Drivers Transformation. The project starts from the open-cut section of the Jiluo Road Tunnel and ends at National Highway 308, with a total length of 4,383 meters. It is designed as a dual-tube road-rail combined tunnel, with a two-way six-lane highway on the upper level and reserved space for rail transit on the lower level. It crosses beneath the Handan-Jinan Railway and the Queshan Reservoir by shield tunneling. The shield-driven section is 2,045 meters long, the segment outer diameter is 15.2 meters, and the shield machine cutterhead excavation diameter is 15.76 meters, making it currently the largest-diameter road-rail combined tunnel under construction in China.

The project is characterized by deep foundation pits, shallow cover, large diameter, long distance, and high risk. Based on the construction experience of the Jinan Yellow River Jiluo Road Tunnel and in light of geological features such as silty clay and localized calcareous concretions, the China Railway 14th Bureau project team carried out targeted upgrades and optimization of the shield machine cutterhead, flushing system, and other components. Efficiency was increased by 20%, with a maximum daily advance of 18 meters and a maximum monthly advance of 332 meters. The tunnel is impermeable and leak-free, solid inside and aesthetically pleasing outside.

This is the first time in China that a super-large-diameter shield tunnel has crossed a medium-to-large reservoir, involving many controlling factors and high environmental protection requirements. To overcome the challenge of the long-distance crossing of the Queshan Reservoir, Jinan Urban Construction Group organized an expert review meeting on the construction plan. The project department established the "Wang Chao Innovation Studio" and, together with Shandong University, carried out research on the topic "Long-Distance Crossing of a Large Reservoir by a Super-Large-Diameter Slurry Shield." For the first time, a "waterproof curtain" was developed to place a "protective cover" over the reservoir bottom, effectively ensuring soil stability. At the same time, water quality monitoring frequency was increased to ensure zero pollution, zero discharge, and zero leakage during the tunneling process.