On the morning of July 18, the construction of the First Tunnel of Wanjiang—the Wuhu Chengnan River-Crossing Tunnel—reached a major construction milestone. The cutterhead of the tunnel's first tunneling shield machine, "Wanjiang Endeavor," weighing 650 tons and standing five stories tall, was successfully hoisted into place, marking the imminent completion of the shield machine's assembly.

The front of the cutterhead of the "Wanjiang Endeavor" shield machine is painted with the image of the "Juzi Bird," the city symbol of Wuhu. With a maximum diameter of 15.07 meters, the cutterhead together with its lifting rig weighs approximately 650 tons, making it the heaviest and largest component to be hoisted for the entire shield machine. Hoisting it from the surface into the 27-meter-deep shield launching shaft also represents the greatest risk in the hoisting of the entire shield machine.

The builders from the China Railway 14th Bureau Group Co., Ltd. braved the scorching summer heat and high temperatures, withstood the "roasting" test, overcame the impact of heavy rainfall during the flood season, and worked hard for 60 days and nights to smoothly and rapidly complete the welding and assembly of the cutterhead. With meticulous planning, careful organization, and rigorous review, and with the joint cooperation of two large crawler cranes of 1,250 tons and 400 tons, they successfully lowered the cutterhead into the shaft over the course of 2 hours, bringing a perfect conclusion to the major milestone of assembling the "Wanjiang Endeavor" shield machine. The successful hoisting of the cutterhead of the "Wanjiang Endeavor" shield machine has laid a solid foundation for the next step: the launching of the shield machine.

The reporter learned that the Wuhu Chengnan River-Crossing Tunnel is located at the great bend of the Yangtze River in the urban area of Wuhu, in the Wanjiang section of the Yangtze River. It starts from Weiyi Road in the Jiangbei New City in the west and ends at Dagongshan Road in the main urban area south of the river in the east. The project has a total length of 5.96 kilometers, of which the shield tunnel is 3.95 kilometers long. The shield tunnel segments have an inner diameter of 13.3 meters and an outer diameter of 14.5 meters.

According to the project contractor, the project has four prominent major difficulties and key challenges. First, "long-distance high-strength rock and high water pressure": the tunnel crosses in long-distance transitions through four different strata, with rock strength reaching up to 113.4 MPa and water and soil pressure of 7.5 bar. The tunnel crosses a bedrock section of nearly 1,800 meters in a single long-distance run beneath the riverbed, and the cutterhead tools of the shield machine will experience very severe wear. The technical difficulty and tunneling risk are rare among similar tunnels worldwide. Second, "complex strata and difficult control": the tunnel transitions through three completely different types of strata—soft, hard, and cohesive—making control of shield tunneling extremely difficult. Third, "high risk of crossing faults": the shield machine crosses a fault fracture zone beneath the Yangtze River bed, where river water can easily intrude and the tunnel face is highly unstable, resulting in high tunneling risk. Fourth, "flammable gas hidden beneath the riverbank": flammable gas exists within a 600-meter range of the Yangtze River south bank beach, greatly affecting the safety of shield tunneling construction and posing high construction risk.

After the tunnel is completed, it will become another important river-crossing artery in Wuhu, greatly improving river-crossing traffic and being of great significance for advancing Wuhu's "river-embracing development."