China building the world's longest undersea tunnel

 

An underwater tunnel is a tunnel which is partly
 or wholly constructed under the sea or a river

Have you ever thought that one day,high-speed rail will be able to run under the sea? 

As a major country in infrastructure construction, China has been building roads and bridges frantically in recent decades. China builds the world's longest undersea tunnel. It is understood that to take up the connection between Zhoushan and Ningbo, China plans to invest 4 billion dollars to build the world's longest undersea high-speed rail tunnel, Chinese engineers named it the Jintang undersea tunnel. At present, there are more than 20 undersea tunnels that have been built or are planned to be built around the world, among which there are many representative world-class undersea tunnels, such as the British and French undersea tunnels, the Seikan tunnel, and the Tsushima Strait Tunnel in Japan. According to Chinese plans, engineers intend to spend six years building the Jintang undersea tunnel. As soon as the news came out, it immediately aroused heated discussions internationally. Western engineers believe that the Chinese are wasting time and money doing something that can never be done. Because of the construction of the submarine high-speed rail tunnel, the technical difficulties and engineering volume faced are unimaginable. However, China plans to spend six years building the longest undersea tunnel in the world. Such a mega project is impossible to complete, it is simply a fantasy. Facing the cynicithirsty of western countries, Chinese engineers will rise to the challenge. They will use their actions and results to prove China's construction strength to the world. Jintang undersea Tunnel is one of the most important projects of the Yongzhou-Zhuhai Railway. And projects like the construction of undersea tunnels, every meter of tunnel excavation has great difficulties to overcome. 

The main works of the whole project will be carried out using the construction method of bridge and tunnel combination. The entire undersea tunnel is 16.2 kilometers long, the maximum buried depth is 78 meters, the maximum burial depth in the sea area is 50 meters, and the tunnel is 14 meters in diameter. This also means that during the construction of the undersea tunnel, it is necessary to implement multi-section tunnel mouth docking. Whether it is the length of the segment the tunnel segment or the difficulty of docking, it ranks first in the world. After the construction is completed, it will set a new record for the length of the world's submarine tunnel. It will also be China's first undersea high-speed rail tunnel. Chinese engineers mainly use the open-cut method, shield method, and mine method to carry out construction operations. In the shallow areas where the soil is soft and soft, the open-cut construction technique is adopted. It is to dig the ground directly, and then start to build the interior. The structure to support the tunnel is built first, and finally restores the ground But this method is useless on very hard seabed. Therefore, the shield method is used to excavate tunnels in soft and water-bearing strata, The shield machine needs to be disassembled as a whole without damage and sent to the excavation section. From the place where the silt is very soft, the cutting device excavates, Then the shield machine needs to support the surrounding rock with its shell. while advancing the excavation, the soil, gravel, and mud are transported to the outside of the tunnel through the conveyor belt. When the geological complex and hard rock layers are reached, it is necessary to use the mining method to excavate, Excavate the section by drilling and blasting. To avoid the tunnel collapse accident during the construction process, it can only be excavated slowly and blasted multiple times. When Chinese engineers built the undersea tunnel of the Hong Kong-Zhuhai-Macao Bridge, they used the construction method of immersed tubes. First, the immersed tube tunnel is built on land, then the immersed tube is placed on the seabed, and finally sunk into the seabed and spliced in sequence. 

The Jintang undersea tunnel adopts the shield method, and the total length of the undersea shield section exceeds the Hong Kong-Zhuhai-Macao Bridge by nearly 10 kilometers. It can be called the largest undersea tunnel in the world. Therefore, in terms of engineering volume, the construction difficulty of the Jintang undersea Tunnel is far more difficult than that of the Hong Kong-Zhuhai-Macao Bridge. In addition, the local natural conditions also have a very negative impact on the construction. The first is the effect of water pressure. Since the Jintang Submarine Tunnel is located in the sea at a depth of 78 meters, its seabed pressure is as high as 1.0 MPa. Previously, the most advanced construction technology in China could only withstand a pressure of 0.7 MPa. Even the undersea tunnel of the Hong Kong-Zhuhai-Macao Bridge has a pressure of only 0.8 MPa during construction. At that time, China will need to achieve technological breakthroughs in this area before it can start construction. As long as the Jintang undersea tunnel project is completed, it will be a major breakthrough for China's infrastructure technology, marking a deeper development of China's infrastructure. No country in the world dares to question China's infrastructure capabilities. In general, China has been creating various infrastructure miracles in recent years. From the previous Beijing Daxing Airport, the Hong Kong-Zhuhai-Macao Bridge, to the current Jintang submarine high-speed rail tunnel, these super-engineering projects have proved that China's infrastructure strength has already ranked first in the world. In the past few decades, in the face of the technological blockade of Western countries, Chinese engineers have bravely innovated and faced difficulties, with their wisdom and hard work, have created one incredible Chinese infrastructure miracle after another. China With a series of large-scale infrastructure and mega projects is known internationally as an " infrastructure giant". review of China building the world's longest undersea high-speed rail tunnel, and tell us what you think. 

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