On the morning of September 17, 2021, the first cross-river tunnel in Anhui Province, Wuhu Chengnan Cross-river Tunnel, the "Wanjiang Endeavour" shield machine, which was constructed by the 14th Bureau of China Railway, started successfully, officially embarking on a journey across the Yangtze River.

The Wuhu City South Crossing River Tunnel starts at Jiangbei Planning Xinmin Road and ends at Zhongshan South Road. It has a total length of 5.96 kilometers, of which the shield section is 3.96 kilometers long. It is designed as a two-hole two-way six-lane, and a designed driving speed of 80 kilometers per hour.

Shan Xiangqian, secretary of the Wuhu Municipal Party Committee and director of the Standing Committee of the Municipal People's Congress, announced that the "Wanjiang Fendou Shield Machine was launched."

Wu Yankun, Secretary of the Party Committee and Chairman of the China Railway 14th Bureau, said in a speech that the Wuhu Chengnan Crossing River Tunnel is the largest shield tunnel in Anhui Province. It is difficult to construct and attracts high attention from all walks of life. The beginning of the shield tunneling machine marks this super project. After the preliminary reserves of technology, plans, and funds, the conditions have matured and the main body construction has been accelerated. With the support of an excellent team of experts and standardization, refinement and intelligent management as the starting point, we are striving to create high-quality projects, safety projects, and popular projects to build another monument on the Yangtze River.

Baili Wanjiang First Tunnel Crosses the Yangtze River

113.4 MPa! To challenge the hardest rock in the Yangtze River tunnel, tunnels must be drilled in more than 600-meter-long "gas tanks".

The winner of the National Highest Science and Technology Award and Academician Qian Qihu of the Chinese Academy of Engineering serves as the leader of the preliminary design team of the project. The preliminary design demonstration committee of the project believes that the tunnel is one of the most complex and difficult projects in China and the world today, and it is also the geology of the Yangtze River. One of the shield tunnels with the most complicated conditions, the most difficult construction, and the highest risk.

During the construction, the builders of China Railway 14th Bureau had to drive the shield machine to cross the bedrock section for a long distance of nearly 1,800 meters. Among them, the proved rock strength was as high as 113.4 MPa, which was the hardest and the longest distance encountered in all the Yangtze River tunnels. Long rock geology. The formation is uneven in soft and hard strength, the cutter head is severely worn, and the risk of tool change at the bottom of the river is high.

At the same time, the maximum buried depth of the tunnel is 75 meters, and the maximum water and soil pressure is about 7.5 bar, which is equivalent to the size of a fingernail and bears a weight of 7.5 kg. There are 4 different stratigraphic transitions in the interval. The shield machine encounters a geological fault after completing the upward traversal of the deep trough at the bottom of the river. The surface is unstable and the construction risk is great.

Moreover, there is flammable gas methane hidden within 600 meters of the south bank of the river beach, which is currently the longest tunnel in the area of flammable gas in the Yangtze River.

Tailor-made big country heavy equipment

If a worker wants to do well, he must first sharpen his tools. The "Wanjiang Endeavour" shield machine developed and manufactured by China Railway 14th Bureau Group has a total length of 136 meters, which is equivalent to the length of a row of 13 buses and a total weight of 4,400 tons, which is equivalent to the total weight of 880 adult elephants. The maximum excavation diameter is 15.07 meters, which is equivalent to 5 floors.

In order to overcome geological problems, the shield machine is equipped with a retractable main drive, and the excavation bin is equipped with a high-pressure high-definition telescopic camera, which can observe and grasp the situation of the tunnel face and the excavation bin at any time. The hob is equipped with advanced devices for wear, temperature and rotation detection. The tool status can be monitored in real time. These are the first applications in the same industry in China.

6 Cross the Yangtze River Embankment

The tunnel is located at the big bend of the Yangtze River in Wuhu City. The tunnel route is about 5.5 kilometers and 9 kilometers away from the Yangtze River Bridge on the upper and lower reaches of the Yangtze River Bridge. It needs to cross the Yangtze River levee and sub-dikes one after another. There are silty fine sand and flow-plastic silty silty in the section. Clay layer requires high construction settlement control.

The Wuhu City South Crossing River Tunnel is the first batch of PPP projects in Anhui Province, connecting the Jiangbei New City and the Jiangnan Main City. It is planned to be opened to traffic by the end of 2024. It is of great significance to improve the quality of urban traffic and accelerate the integrated development of the Yangtze River Delta. Editor/Sang Xiaomei