April 15 at 10 a.m
With the 1485th ring segment officially completed assembly
It was built by the 14th Bureau of China Railway
Wuhu City South River Tunnel
Right line shield machine "Wanjiang Struggle"
Successfully crossed the waters of the Yangtze River
Arrive at the south bank of the Yangtze River safely and smoothly
Victory breaks through another major node goal
The Wuhu Chengnan River Crossing Tunnel is the first river crossing tunnel in Anhui Province and the first super-large diameter river crossing tunnel in the Wanjiang section of the Yangtze River, known as the "first tunnel of the Anhui River". The total length of the tunnel is about 5.96 kilometers, and the left and right double lines use two super large diameter 15.07 meters shield machine to excavate in the same direction from Jiangbei to Jiangnan, with "high water pressure of long-distance rock, difficult to control complex formation, high risk of crossing faults, and combustible gas beach bottom storage" four major difficulties, Qian Qihu, academician of the Chinese Academy of Engineering, pointed out that the project can be described as one of the most complex and difficult projects in China and even the world.
1
The long-distance rock has high water pressure
The tunnel passes through dozens of strata, and the geological conditions are extremely complex, which can be called the "geological museum" of shield tunneling. The strength of the rock can be as high as 113.4 megapascals, and the soil and water pressure can reach 7.5 bar. Especially in the 1,800-meter-long bedrock section, the cutterhead cutter of the shield machine is severely worn, and the technical difficulty and excavation risk are rare in this type of tunnel.
2
The stratum is complex and difficult to control
The tunnel passes through three completely different strata: soft, hard and sticky, and in the soft and hard and high viscosity composite strata, the cutterhead forms mud cakes very frequently, which makes it extremely difficult to control the tunneling of the shield machine.
3
There is a high risk of crossing faults
The shield machine crosses the fault fracture zone at the bottom of the Yangtze River, and the Yangtze River water is easy to inflow, and the tunnel face is unstable, and the excavation risk is extremely high.
4
Combustible gas beach bottom hidden
There are 600 meters of combustible gas in the river beach on the south bank of the Yangtze River, and the construction risk is high.
In order to overcome difficulties, since the launch of the right line shield machine, the project team has used scientific and technological means to solve technical problems, carried out nearly 100 targeted transformations on the equipment, adopted more than 20 key core technologies, put forward more than 30 scientific solutions, and carried out repeated tests and demonstrations in combination with the actual situation on site.
Up to now, the left line of the "Wanjiang Fuxing" shield machine is also digging south at full speed, and has been excavated to the 1293 ring, which is expected to reach the south bank of the Yangtze River in August this year. The double line of the Wuhu Chengnan River Crossing Tunnel will strive to be completed by the end of this year. After the completion of the project, it only takes 5 minutes to drive across the river from the tunnel, which will greatly improve the cross-river traffic capacity of Wuhu City, which is of great significance to accelerate the development of Jiangbei region, promote the construction of Wuhu provincial sub-center, and accelerate the economic and social development of both sides of the Yangtze River and the integrated development of the Yangtze River Delta in Anhui Province.
Source: China Railway 14th Bureau Big Shield Company