On July 10, 2021, a super-large diameter shield machine with a panda pattern on the cutter head was off the assembly line in the Changsha Second Industrial Park of China Railway Construction Heavy Industry Group. This shield machine is named "Splendid" and is jointly built by China Railway 14th Bureau Group and China Railway Construction Heavy Industry Group. The excavation diameter is 12.79 meters. It will soon participate in the construction of the Cheng (capital)-Zigong (Gong) high-speed railway Jinxiu tunnel. It is the largest diameter earth pressure balance shield machine with completely independent intellectual property rights developed by China so far.
"Splendid" has a total length of 135 meters, a total weight of 3,000 tons, and an installed power of 7,500 kilowatts, which is about 15 times the volume of the large rocket "Fat Five". The knife plate is painted with Sichuan characteristics. A giant panda with tender bamboo occupies the C position. It is cute and lifelike. It is called "the most adorable great weapon" by netizens. Chengdu-Zigong High-speed Railway is a high-speed railway connecting Chengdu City and Zigong City in Sichuan Province, China. It is an important part of the “Beijing-Kunming Passage”, one of the “Eight Vertical and Eight Horizontal” high-speed railway passages in the “Medium and Long-term Railway Network Planning”. It is the first high-speed railway in Sichuan history with a speed of 350 kilometers per hour.
The Jinxiu Tunnel is a key node project of the Chengdu-Zijiang high-speed railway. The shield section is 2.62 kilometers long. It starts on the west side of Chengdu Yidu Avenue and passes through the city’s main roads and motor vehicle inspection stations. The ground along the line is the prosperous area of Chengdu. Existing railways are densely distributed. The biggest feature of the tunnel is "different depths". The minimum overburden thickness is less than 8 meters, and the maximum buried depth is up to 60 meters. The long-distance stratum of the shield is mudstone. If all the tunnels are dug out The soil, laid flat on the football field, can reach a height of 15 stories.
In order to cope with the complex situation of shallow overburden and multiple structures on the ground along the line, China Railway Construction Heavy Industry and China Railway 14th Bureau customized the equipment and added 23 advanced grouting holes and 28 radial injection ports for the shield machine. Strengthen the pre-grouting reinforcement of the surrounding soil, and radial injection of supporting media to effectively control ground settlement and ensure that ground buildings are not affected. Faced with the extremely high water and soil pressure brought about by the extremely large buried depth of the tunnel, the shield machine adopts high pressure-bearing polyurethane sealing technology, which can withstand water and soil pressure of 10 bar, which is equivalent to 5 adults standing on an egg.
Keywords: Domestic Engineering News
It is reported that the domestic largest diameter earth pressure balance shield machine with completely independent intellectual property rights was successfully developed, providing a strong guarantee for the construction of domestic long and large railway tunnels, and further consolidating the independent controllability of domestic tunnel boring technology and equipment. The project is completed Later, it will be of great significance for optimizing and upgrading the road network structure of Chengdu-Chongqing urban agglomeration and promoting convenient travel for the people along the route. Editor/XuNing
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