"Yonghuang" tunnel shield machine cutter five-story building value of nearly 400 million

Recently, Jinan "three bridges and one tunnel" across the Yellow Sea have passed the experts of the National Yellow Commission. The Jinan City Traffic Committee also announced that the Yellow Crossing Tunnel Project will be groundbreaking during the year. Unlike subway tunnels, the Yellow River Tunnel is much larger than the subway tunnel, except for underwater crossing. So, how do you go underwater through the turbulent Yellow River? For this reason, the author turned to Nanjing, Suzhou, and other places and visited many Yangtze River tunnels that were underwater large-diameter crossings to see how the tunnels were shaped.

Two-lane, double-hole walk takes only 4 minutes

Will be the "biggest" yellow tunnel in China

Recently, Jia Yuliang, the director of the Jinan Municipal Traffic Commission, also introduced the "Three Bridges and One Tunnel" project across the Yellow River during the television political consultation, including the expansion of the Jinan Yellow River Highway Bridge and the extension of the Yellow River Passage (Qilu Bridge) to the north of Qilu Road. Phoenix Road North stretches across the Yellow River Passage (Fenghuang Bridge) and Jiye Road passes through the Yellow Tunnel. Jia Yuliang mentioned the “Yellow Tunnel” and said that the project has been reviewed and passed. Before the end of the year, the tunnel must be constructed first.

According to the preliminary planning scheme, the location of the Yellow River Tunnel is selected from the shortest distance between the two sections of the Yellow River. The starting point of the project is at the intersection of Jiji Road and Zhao'an Road, extending northward along Jiji Road, and tunneling through Erhuan Road North. The Qing-Shan Expressway, the Yellow River Embankment, and the Yellow River canal then proceed along the planned road and the terminal ends with the existing 309 national road. According to the preliminary plan, the Yellow River Tunnel Project at Jihe Road is the main urban road. The total length of the tunnel is 3.68 kilometers, of which the shield section is 2.56 kilometers long. The tunnel adopts a double-track and double-hole scheme. The main line is a two-lane, four-lane road. All types of large, medium and small vehicles can pass through. The opening speed is 60 kilometers per hour, and tunneling takes less than 4 minutes. Due to its all-weather access, the number of vehicles that can be opened to traffic is 21,278 per day; the number of vehicles in the medium-term, 2020 is 33,506, and that of the long-term, 2030 is 44,177 vehicles per day.

Among them, the yellow section of the shield section of the two diameters of 15.2 meters, the upper motor vehicles, two-way 6 lanes, the lower four compartments, respectively, rail traffic, flue, longitudinal escape channel, pipe Gallery. The Yellow River Tunnel in Jinan will become the most "big" yellow tunnel in China.

The cutter used is as high as 5 stories

Large shield machine is 7 times more important than small shield machine

The construction of shields was mentioned here. With the opening of the light rail, Jinan citizens are no strangers to the shield. A long steel dragon walks through the ground and a complete underground tube hole is formed. However, the shield used for wearing yellow is different from the shield for light rail. The shield machine used for wearing yellow is nearly 150 meters long and weighs about 7 times as much as light rail small shield machine. The author came to China Railway 14th Bureau in Suzhou in the GIL tunnel crossing the Yangtze River and saw the legendary shield machine, a steel guy with a diameter of nearly 15 meters and a length of about 150 meters. It is understood that in the future, the shield tunneling machine used in Yellow River in Jinan is even larger than this, and the cutterhead has to be as high as five stories. Chen Peng, an expert of the China Railway 14th Bureau, explained to the author that after the excavation of the 5-story-diameter tunnel, the front of the shield machine was constructed, and the conveyor belt at the bottom of the tunnel would transport a piece of concrete prefabricated. An arc-shaped "big sucker" sucks the prefabricated pipe piece and rotates upwards to the inner wall. These pieces form a support for the newly excavated tunnel, ensuring that the tunnel does not collapse due to external pressure. "You don't look at the speed of the shield machine. But as long as the shield passes, the tunnel will basically take shape."

According to Chen Peng, the segments that make up the circular tunnel wall are assembled in the shield machine shell with an accuracy of up to millimeters. The shield machine is driven by the hydraulic jacks. Every 2 meters forward, it is assembled into a new piece of pipe, and finally forms a sealed cement pipe. In this way, the tunnel is driven, the ring is split, the tunnel is driven, and the ring is put together. The tunnel is extended forward in a continuous cycle. In addition, the shield machine is now very advanced. At the same time, it will automatically set up box culverts in circular tunnels, and build prefabricated cement panels on the culverts to form the future road surface.

Shaving the soil into mud

A large shield machine nearly 400 million yuan

Chen Peng said that the front end of the shield machine's main machine is the cutterhead of the excavation stratum. There are two or three hundred cutters with cutters, heavy scrapers and edge blades installed on the cutterhead. At the same time excavation. So how does the mud get out? Behind the cutterhead are the heading and work chambers, which are two enclosed sections separated by a pressure chamber partition. About two-thirds of the work chamber is filled with mud made of bentonite, which is called a shield machine. "Blood", two mud pipes extended to the ground. Into the slurry pipe, fresh mud is continuously injected into the excavation chamber, and the slag soil excavated by the cutterhead is melted into the mud and transported to the outside of the tunnel through another mud discharge pipe.

Shield machine buried in the ground to dig, how to go to the intended target? Chen Peng told the author that after the end of the assembly of the shield machine, the excavation will be started from the originating well, and the direction of the shield machine will be controlled by the navigation system installed on the shield machine to dig toward the established target. “If there is a deviation of 1 cm in the direction, the navigation system will prompt corrective actions and will not take detours.” Of course, the cost of this machine is nearly 400 million yuan. ( Sun Yan )