"Wanjiang struggle" shield machine successfully off the line "800 miles of Wanjiang first tunnel" has made significant progress

The shield tunneling machine "wanjiang struggle", built by China railway construction company, rolled off the production line in changsha, capital of central China's changsha city, on March 26, and will be transported to the site for assembly and excavation of the Yangtze river tunnel south of wuhu. This is the first super-large diameter shield tunnel across the Yangtze River in Anhui Province, marking the addition of another channel across the Yangtze River Economic Belt and the acceleration of the construction of the big channel connecting the south of Wuhu and the emerging industrial concentration area in Jiangbei. It is of great significance to the "river-embracing development" of Wuhu.

Wuhu, also known as Jiangcheng, is a big city in the national development plan of the Yangtze River Delta City Cluster. It is a national historical and cultural city, a national comprehensive transportation hub, a national smart pilot city, a national top 100 cities of digital economy, and its economic aggregate ranks the second place in Anhui Province. The name card of the city is "Pearl of the Yangtze River, City of Innovation". However, due to the natural barrier of the Yangtze River, the development of both sides of the river is not balanced, so it is urgent to build a new channel across the river.

Located in Jiujiang District, Chengnan Tunnel across the Yangtze River starts from Planning Weiyi Road in the north, crosses the Yangtze River in the south and connects with Dagongshan Road in Yijiang District in the south, with a total length of about 5.9 kilometers. The tunnel is about 9 kilometers away from Wuhu Yangtze River Bridge in the downstream, and about 5.5 kilometers away from Shanghehang Bridge under construction in the downstream. After it is completed and opened to traffic, the fastest time to drive across the river is 5 minutes. According to Li Dongsheng, project director of China Railway 14th Bureau Group, the 3,965 meters long tunnel will be constructed by the shield method across the Yangtze River. It will be designed as a two-way six-lane urban expressway with a driving speed of 80 kilometers per hour. The tunnel is designed in double pipe and two-way direction, the outer diameter of the segment is 14.5 meters, and two shield tunneling machines with an excavation diameter of 15.07 meters are used for construction. Known as the "Yangtze River 800 miles of Wan River first tunnel."

According to the introduction, the crossing difficulties of the shield section are mainly concentrated in the hard rock with full section length of 1,140 meters and the composite stratum with soft upper and hard bottom of 630 meters. The quartz content of the rock is up to 80% and the strength is up to 114 MPa. 35 meters geological fault fracture zone, there are combustible gas methane in some areas of Jiangnan. It crosses a long distance of nearly 4,000 meters at one time, and the maximum soil and water pressure is about 7.5bar. It is one of the most difficult tunnels in the Yangtze River area so far. To cope with the complex problem, in terms of money seven tiger academician of Chinese Academy of Engineering for the group leader of expert academician team, under the guidance of the project according to the characteristics of the formation of hard rock composite shield construction machine, equipment total length of 136 meters, about 4400 tons, the total weight of shield machine cutter head weighs 572 tons, total power equipment 10014 kilowatts, the maximum thrust 222.173 million cattle, main drive maximum 10 bar under pressure. The cutter head is equipped with 315 tools, among which the normal pressure replaceable hob is double-axis double-edge hob, the most knife spacing is 80 mm, and has the hobbing interchange function. These are the first application in China, and it is one of the most advanced intelligent tunneling equipment.