The Jinan Huanggang Road Yellow River Crossing Tunnel – a major infrastructure project in Jinan, capital of East China's Shandong province – recently surpassed 2,000 meters in excavation, with nearly two-thirds of the shield tunneling completed.

The two-story road tunnel – with three lanes in each direction – aims to connect the urban area on the south side of the Yellow River, with a new state-level strategic pilot zone for free trade, innovation and reform on the north side of the city. The tunnel's full breakthrough is expected by the end of the year.

Spanning 5,755 meters, the tunnel includes a 3,290-meter shield section, excavated using a "Shanhe" tunnel boring machine – the world's largest slurry balance shield machine.

Measuring 163m long and weighing 5,200 metric tons, it's equipped with cutting-edge intelligent technology.

The tunnel follows a unique "V" shape, reaching its lowest point at 1,820m before transitioning to an upward ascent. Its innovative single-tube, double-deck design is said to optimize underground space and reduce costs by about 15 percent compared with conventional twin-tube tunnels.

However, this also presents challenges such as complex structural procedures and limited workspace.

"To tackle these challenges, we have refined construction planning through multiple scheduling meetings, ensuring smooth shield tunneling," said Zhou Xiang, a senior engineer with the project.

The project team has already set a world record – achieving a monthly advance of 426m for a 17-meter-diameter shield tunnel.

Once complete, the tunnel will strengthen connectivity between main urban area and the Jinan's Start-up Area for Growth Drivers Transformation. It's also expected to accelerate regional development and support ecological protection and high-quality growth along the Yellow River.

An inside view of the enormous new tunnel whose construction is in full swing. [Photo/WeChat account: qiluwang]