On May 9, the "Qihang" tunnel boring machine (TBM), equipped with a massive 15.06-meter diameter cutting wheel, began tunneling operations on the south line of the Yellow River Tunnel in Jinan. Undertaken by CRCC, this marks the start of shield tunneling for one of China’s largest-diameter river-crossing tunnel projects.

The tunnel is a key infrastructure project that connects Jinan Yaoqiang International Airport with the city's New and Old Growth Driver Conversion Pilot Zone. With a total length of 3,888 meters, it is designed as a six-lane, bidirectional highway with a speed limit of 60 km/h. Shield tunneling will account for 3,252 meters of the total length.

The project presents considerable engineering challenges. The TBM must pass beneath the Yellow River, cross levees on both banks, and navigate silting zones. The ground is primarily composed of sticky silty clay embedded with extremely hard calcium nodules, which can damage cutting tools, cause material buildup on the cutter head, and jam pumps. Further complicating construction, the Yellow River in Jinan flows at a higher elevation than the surrounding terrain, with water levels consistently above the city surface. This requires strict control of ground settlement during tunneling.

Once completed and opened to traffic, the tunnel will significantly enhance the road network on both sides of the Yellow River and improve connectivity between urban expressways, surrounding highways, and key transportation hubs across the region.