China's first constant-pressure tool-changing large-diameter slurry balancer shield acceptance

On September 23, jointly developed by Tiejian Heavy Industry and China Railway 14 Bureau, the first domestic constant pressure tool-changing large-diameter slurry-water balance shield machine “Yuan-an” with complete independent intellectual property rights was successfully accepted and successfully went offline. Another major leap in the research and development of homemade self-shielding technology has filled China's gap in the atmospheric pressure change tool technology of shield machines.

The design of the "Chun'an" cutterhead is like a blossoming peach flower. It is a soft and artistic atmosphere for the country's traditionally strong, and it is currently one of the highest valued shield machines in China. Its excavation diameter 11.75m, machine length 132m, total weight about 3000t, installed power 6100kW. It is expected that by the end of September, it will arrive at the construction site of the Changjiang Tuijiang River Crossing Tunnel, and the mission of “crossing the river and crossing the lake” will be opened to make contributions to the construction of the rail transit in the Huxiang Land.

It is understood that the Changde Lancang River Crossing Tunnel is the first urban traffic cross-river tunnel in the Lijiang River Basin in Hunan, and is also the first large-diameter river shield tunnel. The total investment of the tunnel is 2.544 billion yuan. It is designed to have a total length of 2,240 meters. The design speed is 60 kilometers per hour. The construction period is 3 years. After the completion of the tunnel, the cross-strait vehicles can cross the river within 5 minutes. The tunnel was constructed by the China Railway 14th Bureau and was constructed using a slurry shield method. The shield section of the river was 1680 meters long. According to the results of geological surveys, the Changjiang-Xiajiang River Crossing Tunnel features large excavation sections, complex hydrogeological conditions, high strength through the formation, high permeability, and high water pressure. The flood control embankment of the Lancang River is artificially filled and contains a lot of stones and pebbles, which is not conducive to tunnel construction. The geological layer of the tunnel is rich in pebbles and has poor homogeneity. It is mainly quartz and has a point load strength of 0.51-5.21 Mpa, which will adversely affect the construction of the cutterhead of the shield machine.

Usually, the pressure balance shield machine must be constructed with pressure. Only when the pressure balance is maintained, the construction of the face can be controlled and the construction safety can be guaranteed. Therefore, no matter the work is still not working, the pressure cabin behind the cutter head of the shield machine We must keep the pressure on the outside. Shield machine replacement tools need to be operated in a high pressure environment that is 2 times higher than normal conditions. This process is very dangerous. Previously, this work was generally performed by senior divers. The labor remuneration was about 10,000 yuan per hour, the working time was short, and the preparation period was long. The process of entering the pressure cabin to get out of the cabin took at least 6 hours, and only a part of the tools can be changed at a time. . The degassing process takes at least 2 hours for the extravehicular process, otherwise the high-concentration nitrogen dissolved in the blood will be released and expanded under rapidly reduced pressure, exploding the lungs of the operators, and it is very dangerous. Need to be specially equipped with ambulances. The scarcity of personnel, high labor remuneration, and low work efficiency are problems that have long plagued shield machines with pressure change tools.

For the industry difficulty of high difficulty and high risk of tool replacement in the construction process of shield machine, Tiejian Heavy Industry adopts self-developed constant pressure tool change technology on the equipment, which can effectively avoid muddy water shield changing by the pressure of the staff. The risk of operations greatly improves the efficiency of tool change operations, reduces the cost of tool change under pressure conditions, makes the tool change operations safer, more reliable and more convenient, and transforms high-strength, high-risk, and high-pollution tunneling work operations into relatives. Safe, reliable and efficient green construction mode.

In addition to the constant pressure tool change this "unique stunt", "Jian On" combines many advanced technologies in one. It integrates the integrated control technology independently researched and developed by Tiejian Heavy Industry. The performance of the entire machine is advanced and reliable, and the integrated assembly and culvert technology is adopted. The prefabricated box and culvert can be assembled synchronously during the excavation construction process, shortening the construction period, and greatly improving the overall construction efficiency of the tunnel. The application of high-precision gas-hydraulic pressure balancing control technology ensures continuous high-precision constant pressure control of the face during excavation and excavation; and the optimized matching technology of the high-power mud circulation flushing system provides a highly efficient system for excavation and transportation. The integrated safeguard measures facilitate flexible control and real-time operation of parameter adjustment. It fully satisfies the requirements of rapid, high-quality, high-efficiency, safety, environmental protection, and high degree of integration of tunnel construction, and represents the modern development direction of tunnel construction in China.

At present, the excavation diameter of the Tiejian Heavy-duty Slurry Shield Machine covers an area of ​​3 to 17 meters. With excellent construction performance and extremely high technical standards, it has promoted the upgrading of China's tunneling equipment industry and improved the level of China's equipment manufacturing industry and major equipment. The international core competitiveness indicates that China's modern large-scale tunnel construction equipment has reached the world's leading level (This article comes from Tiejian Heavy Industry Huang Jie Liao Jinjun Fan Ruiqiang)