The longest high-speed rail shield tunnel in China runs through

Original title: Jingshen Passenger University Wangjing Tunnel, which is the longest high-speed rail shield tunnel in the country

On the morning of August 28th, with the "Wangjing" shield machine breaking holes, the Beijing-Shenyang Railway Passenger Dedicated Line(referred to as Jingshen Passenger College) Wangjing Tunnel project, which was built by the China Railway 14th Bureau Group and other units, was successfully completed. It marks the first place in Beijing. It is also the longest urban high-speed rail shield tunnel in the country to complete the main project, laying a solid foundation for the completion and opening of the entire line.

Wangjing Tunnel has been the first to be excavated by the "Wangjing" shield machine since December 28, 2016. It has a total length of 8,000 meters and is the only two-lane single-hole large-diameter shield tunnel across the board. The outer diameter of the tunnel pipe is 10.5 meters and the inner diameter is 9.5 meters. The construction of the two Trump cards of the domestic shield tunnel, the China Railway 14th Bureau and the China Railway Tunnel Bureau, adopts four domestic mud and water balance Shields with a diameter of 10.9 meters. The machine is excavated from both ends to the middle.

Jing Shen Ke specializes in the Beijing Railway Hub Starfire Station and ends at Shenyang Railway Terminal. The line has a total length of 698 kilometers, a design speed of 350 kilometers per hour, a total investment of 124.5 billion yuan, and a total construction period of 5 years. It is planned to be completed by the end of December 2020. By then, the train time between Beijing and Shenyang will be compressed to 2.5 hours and Beijing to Harbin will arrive in 4 hours

The more security passes, the more risk sources.

According to the project leader of the China Railway 14th Bureau, the engineering difficulties of the Wangjing Tunnel mainly focus on the safety risks encountered in the construction of large-scale, long-distance, and water-rich strata. The tunnel passes underground through major risk sources such as Capital Airport Expressway, Airport Express Rail, Metro Line 15, Maquan Subway Station, Red Brick Art Center, Sewage Treatment Plant, High Pressure Tower Frame, Multiple residential areas and tall buildings. High settlement control standards, high construction and environmental safety risks.

The deepest part of the tunnel is 43 meters. It is only 0.6 meters away from the station maintenance structure. The crossing distance is 120 meters long. It passes through the station's dense fork area continuously. The deformation control requirements are within 1 mm or less, and it is also necessary to ensure that nearly 700 subway trains are operated every day. safe.

There are more than 200 thermal pipelines and a large number of wells buried more than 100 meters deep in the construction area. If the measures are improper, it is easy to lead to an imbalance in the air pressure in the construction of the shield, which brings major safety hazards to the construction and ground structures.

Some sections of the tunnel vault cover only 10.5 meters, which is smaller than the diameter of the shield machine, and the stratum carrying capacity is poor, increasing the difficulty of construction."In response to major risk sources, our engineers and technicians have strengthened their scientific and technological efforts. Through the analysis of settlement mechanisms and causes, we have developed a five-stage control method, optimized excavation parameters, and strengthened construction monitoring. After the tunnel was formed, the results of third-party testing showed that: The maximum settlement value of the Maquan subway station is 0.68 mm, which is not only the best control of the entire line, but also creates the highest level of operation of the subway station over long distances in China. "Wang Lei, shield manager of the project Department of the 14th Bureau of China Railway, said

Construction zero pollution service life 100 years

The stratum in which the tunnel is located is dominated by clay. Each time two meters of ring are excavated, 185 cubic meters of earth are excavated, and the amount of slag discharged by the four shield machines reaches 7,400 cubic meters a day. The entire tunnel construction produces about 3 million cubic meters of waste pulp. It needs to be harmless. Treatment.

In order to meet the requirements of environmental protection standards, construction units have built 4 sets of muddy water separation facilities. To this end, the project participants, together with well-known domestic institutions and scientific research institutions, have conducted scientific research on world-class problems in the separation of ultra-fine soil particles, developed national invention patent technologies, and applied new materials and techniques to solidify and filter the discarded pulp. The separation of micro-granular mud water was successfully completed, and the difficulties in the industry were overcome. Zero leakage, zero emissions, and zero pollution were achieved.

At the same time, the head of the Jingshen Passenger College Project of the 14th China Railway Bureau introduced that the Wangjing Tunnel has a design life of 100 years and an earthquake-resistant level of 10. In order to build first-class shield tunnel tubes, the first automated pipe flow production line in the Beijing area was established at the Fangshanqiao Plant, which belongs to the China Railway 14th Bureau. The central system control was adopted, and every link from pipe production to maintenance was realized. Informatization and automation control. It has greatly improved the production capacity and product quality of the tube. The 6955 ring and 62595 pieces of pipe pieces were assembled naturally and there was no leakage.

Autonomous development of Shields across the city undergroundThe most worth mentioning is the "Wangjing" shield used in tunnel construction. This is a joint development of the China Railway 14th Bureau and China Railway Construction Heavy Industry Group. It is a key project of the National 863 Plan and the first high-speed rail large-diameter muddy balance shield machine with complete independent intellectual property rights.

The captain of the shield is 87 meters, with a total weight of 1,900 tons and an installed power of 5,300 kilowatts. It integrates the functions of tunnel excavation, lining, ballast, and guidance. It is known as an underground tunnel digging into a smart robot and can safely and smoothly cross complex strata. More than 200 knives, Outstanding completion of the tunnel excavation mission.

The shield construction method adopted in the project has effectively overcome the problem of interference between underground pipelines and pipelines by excavating underground tunnels, and it can also effectively evade the relocation of traditional ground projects to existing municipal facilities such as roads, pipe networks, pedestrian bridges, and bus platforms. Reducing the economic disputes, social conflicts and disturbance caused by the demolition of buildings and demolition, reducing the noise pollution of the surrounding environment and the spatial division of existing communities in the late high-speed rail operation, and minimizing the interference with the normal life and social order of citizens and communities.

Beijing-Shenyang Passenger College is an important line connecting the Beijing-Tianjin-Hebei area and the old industrial base in the Northeast region. As the second fast railway route to enter the customs area in the Northeast region, it will effectively ease the issue of the carrying capacity and strategic pressure of the existing access routes and accelerate the "Beijing-Tianjin-Hebei coordinated development." Speeding up the "strategy of rejuvenating the old industrial base in the Northeast" plays an important role.

According to the introduction, Jingshen Passenger College is the last "one vertical" of the "four vertical and four horizontal" passenger railway network of the National "medium and long term railway network plan"-an important part of the Beijing-Harbin(Dalian) passenger dedicated line and the closing project.