Why is the undersea tunnel dug so deep without being submerged by the sea? How?

Over the years, China has built many super projects, such as the Three Gorges Dam, the South-to-North Water Diversion Project, the Hong Kong-Zhuhai-Macao Bridge, and so on, all of which represent the highest level of construction in China to a certain extent. In many engineering construction projects, the construction of the submarine tunnel is believed to be the most difficult, because the submarine tunnel not only has to overcome the resistance of the seawater, but also must build a fully enclosed tunnel on the seabed, the construction difficulty is very high, at present, we have only 3 submarine tunnels that have been opened to traffic, namely Xiamen Xiang'an Tunnel, Qingdao Jiaozhou Bay Submarine Tunnel and Hong Kong-Zhuhai-Macao Bridge Submarine Tunnel, which shows how difficult the construction of the submarine tunnel is. In this regard, many friends have a question, why the undersea tunnel is dug so deep in the sea, but the interior will not be flooded by seawater, let alone leak, how is this done?

Let's take a look.

The construction of the submarine tunnel has been the continuous exploration and research of the engineers, at present, the three domestic submarine tunnels mainly use the drilling and blasting method and the immersed pipe method to construct, first of all, we talk about the drilling and blasting method, the drilling and blasting method is a more traditional tunnel excavation method, this tunnel construction method is not in direct contact with the seawater, but in the rock layer below the seabed to build a tunnel, the engineers first plan the route of the submarine tunnel, and then calculate the amount of explosives and the blasting point before blasting, After the blasting is completed, the gravel and other debris are cleaned out, and then the machine excavation method is used to dig through the tunnel little by little, and the Xiang'an Tunnel in Xiamen and the Qingdao Jiaozhou Bay Submarine Tunnel are all built in this way. However, this method has strong limitations, it has high requirements for the geology of the seabed, and cannot be applied to all submarine tunnel construction methods. What if it's a sea with soft rocks and flat terrain?

Generally, in this case, the immersed tube method is used, which is to put the pre-designed immersed tube directly into the designated water area, and finally connect the tunnel by splicing. Of course, the answer is not, the splicing between the immersed pipes is generally fixed with concrete, and the tightness between the immersed pipe and the immersed pipe is originally very high, so the submarine tunnel will not leak, let alone be submerged by seawater. The Hong Kong-Zhuhai-Macao Bridge undersea tunnel is designed and built using the immersed tube method, which can withstand natural disasters such as ** and tsunamis, and the seismic level has reached level 7, and there is no problem in terms of safety, so we don't have to worry about the inside of the undersea tunnel being submerged.

At present, the main tunnel construction methods in China are drilling and blasting method and immersed tube method, both of which can ensure the safety of the tunnel to the greatest extent and ensure that the tunnel will not be flooded by seawater. After all, if the undersea tunnel collapses or leaks, the consequences are very serious, so the construction of the undersea tunnel is very rigorous, and we should praise the wisdom of the engineers.

The splicing between the immersed pipes is generally fixed with concrete, and the tightness between the immersed pipes and the immersed pipes is very high, so there will be no water leakage in the submarine tunnel, let alone being submerged by seawater.

In addition, the main tunnel construction methods in China are drilling and blasting method and immersed pipe method, both of which can ensure the safety of the tunnel to the greatest extent and ensure that the tunnel will not be flooded by seawater.

Because the undersea tunnel was sealed at the time of construction, it will not be submerged by the sea. The undersea tunnel is generally immersed into the sea, and the immersed tube will be opened only after the two immersed tubes communicate. It is possible to close the undersea tunnel to prevent seawater from backing up.

Because the current level of scientific and technological development is very good, but also because the materials used in the undersea tunnel are very strong, and the cost of building an undersea tunnel is very huge.

The sea is so deep and full of water, how was the undersea tunnel built? After reading the capital letters, I was convinced.

The undersea tunnel is under the seabed. The undersea tunnel is similar to the subway in the city, except that the subway is underground, while the undersea tunnel is a tunnel dug in the rock formation under the sea.

The main purpose of the construction of the undersea tunnel was to provide a road on the seabed that would allow people and vehicles to pass without hindering the navigation of ships. The construction of the undersea tunnel can not only effectively alleviate the situation of land traffic congestion, but also promote the economic development of small and medium-sized cities around the coast of the tunnel.

The main structure of the undersea tunnel.

There are two main ways to construct undersea tunnels, namely the immersed tube method and the shield method. The immersed tube method is to first build a section of the main structure of the tunnel on the land, and then dredge the seabed to dig a flat trench to connect the land tunnel with the submarine trench. Finally, the trench is backfilled and the top of the tunnel is covered with a crest.

The shield method is to dig a tunnel tunnel directly in the underwater formation. In this method, two shafts are dug at the beginning and end of the tunnel, and then the shield machine is used to excavate from the starting shaft and pass through the underwater stratum to open the two shafts.

Construction Method.

The submarine tunnel was excavated using a giant rock drilling rig from both ends at the same time. The shovel head of the rock digger is hard and sharp, and it is indestructible. The diameter of the borehole is equivalent to the design diameter of the tunnel, and the inner wall of the tunnel is immediately processed every tens of centimeters excavated, all in one go.

In order to ensure the correct direction of the excavation at both ends, laser guidance is adopted. In the case that the seabed geology is complex and cannot be excavated in this way, the prefabricated reinforced concrete tunnel is used and the method of sinking and fixing on the seabed is adopted.

There are four main construction methods for the excavation of undersea tunnels. Drilling and blasting method is a construction method that mainly uses the drilling hole blasting method to excavate the section and build tunnels and underground works.

Judging from the current state of transportation, the subway should be the most convenient and fast choice for urban transportation, and we all know that the subway is built underground, so how is the undersea tunnel built?

It is very difficult to build a tunnel inside the seabed, and China uses the immersed tube method to build an undersea tunnel.

Building a tunnel on land is a difficult task in itself, and it is even more difficult to build an undersea tunnel in the sea. Even if a suitable site is found on the seabed, it is unimaginably difficult to build a tunnel inside the seabed, and it may be half built and abandoned halfway.

It is very difficult to build tunnels under the sea.

The construction of tunnels on the seabed is different from the road, the construction of tunnels on the road chain, you can survey the rock and geological problems before and after at any time, once the problem is measurable, the seabed is unpredictable, and various things may happen at any time, after all, the seawater contains very large corrosiveness, if the material used can not resist corrosion, even if the submarine tunnel is repaired, it will not take a long time, there is a great danger.

Immersed tube method to construct undersea tunnels.

The Hong Kong-Macao-Zhuhai Bridge Undersea Tunnel is currently the only undersea tunnel in the world that is constructed using the deep immersed tube method. Although the immersed tube method sounds very simple, it is very difficult to achieve the docking of pipes in the seabed, and it is very difficult to achieve precision, basically requiring that the error between the two pipes should not exceed two millimeters. First of all, the pipeline must be built on land, then the ends are sealed, and then it will be sunk to the bottom of the sea for docking, which will take a long time to complete.

Other methods of constructing undersea tunnels.

In addition to the immersed tube method adopted in China, the blasting method and the shield method can also be used to build submarine tunnels. The blasting method is a common method for building land tunnels, and it is also the simplest and most crude method, which mainly blows some rocks on the seabed and then opens the tunnel, but this process cannot be carried out in seawater. The shield method requires the use of a shield machine to excavate the rock, which can be achieved if it is a relatively short tunnel, and cannot be completed by a submarine tunnel that is too long.

If you want to build an undersea tunnel, you need to consider not only the pressure of the seawater, but also the underwater environment. The method used in the construction of undersea tunnels in China is called the immersed tube method.

We use shield machines to build tunnels at a certain depth in rock formations and on the seabed with the support of mature geological science and technology.

The difficulty of building the submarine tunnel is very large, when China carries out the construction of the submarine tunnel, the first thing is to face different geographical environments, use different geographical methods, and the most commonly used way is the immersed tube method to try to avoid the construction of the tunnel by excavation, and in the subsequent construction process, when the mining method and terrain blasting are used for excavation, it is more careful.

The construction of an undersea tunnel is very difficult and almost impossible to complete. Our country was built by the immersed tube method.

How powerful is the undersea tunnel? How was it built? The undersea tunnel runs through the entire ocean, so it's very powerful, and it's built through four typesThat.

Fourth, the shield method. At present, there are more than 20 undersea tunnels built in the world, the most representative of which is the cold invasion tunnel in Tokyo, Japan. The Anglo-French Undersea Tunnel and the Harbour Tunnel of the Hong Kong-Zhiao Bridge in China.

The undersea tunnel mainly solves the traffic problem between the two sides of the strait.

With the continuous development of China's infrastructure level, the excavation of tunnels under the seabed has become an emerging project. The biggest challenge to overcome in the cross-sea tunnel is how to prevent seawater from interfering with the excavation of the tunnel. At present, there are two main ways to build undersea tunnels, 10-ton construction, and the second is the urban management method.

The break-out method is the most advanced and efficient method at the moment. It is necessary to use a large-scale purchasing machine, which sinks to the bottom of the sea during construction and propels. When the surrounding rock is supported by the shell and segments of the machine, the tunnel collapse is prevented.

The head of the machine has a huge cutting device with huge blades mounted on it. Under the action of the hydraulic jack, the shield machine moves forward slowly, and the missing device rotates quickly to develop the soil. Most of the excavated earth has been squeezed into the inner wall of the tunnel, and there are only a few large rocks.

It is transported to the outside through the transport unit of the mobile purchase machine. In addition, the purchasing machine will assemble concrete segments while moving forward, which will strengthen the inner wall of the tunnel and have the effect of waterproofing.

The waterproof sealing electricity is set at the splicing place of the segment and the segment, which truly achieves no leakage. Excavation of undersea tunnels is currently the most efficient construction method. It is not affected by bad weather and can be constructed day and night, of course, in addition to the purchase method, there is also a more common method, that is, the urban management method.

Before the advent of the mobile purchase machine, almost all undersea tunnels were excavated by urban management. The urban management method is to sink the pipes into the sea one by one, and the seabed position of the urban management needs to be reinforced before the urban management.

The tugboat then consigns the pipe from the factory by the sea to the sea at the chengguan location, where the pipes are sealed at both ends and filled with air. After the pipe sinks to the bottom of the sea and the splicing is completed, the sealing structure is removed, and in order to prevent water leakage in the tunnel, rubber seals are set between the pipes. Finally, cover the top and sides of the pipe with gravel, etc., to prevent the pipe from floating to a certain extent.

In general, the needle method is only suitable for areas where the riverbed is stable and the water flow is not high. Because of its short construction period and low cost, it is welcomed by countries all over the world.

It is particularly powerful, and after some workers at sea transport the soil out, and then through non-stop mining, a kind of tunnel is formed.

It's very powerful, and there are a lot of problems that need to be taken into account when building. It's built on our powerful technology.

It is particularly powerful, in the process of construction, explosives are generally used to blast the ground open, and then use professional techniques to excavate, such as drilling and blasting.

Tunnels are important transportation hubs that connect the two sides, they can be road tunnels, underwater tunnels or railway tunnels, etc. The undersea tunnel is a difficult tunnel project, which needs to be carefully planned and constructed to ensure its safety and stability, while also considering possible disasters. So, will the undersea tunnel be afraid of flooding?

The drainage system used in the tunnel.

Essentially, tunnel builders take seawater infiltration into account and have taken a number of measures to prevent water from entering the tunnel. Most of the submarine tunnels in coastal areas are not affected by waves and swells due to the deep terrain of the tunnels. In addition, the tunnel's drainage system also controls the ingress of water, so it is relatively safe.

Emergency measures for water ingress.

However, even with adequate drainage measures, there will inevitably be special circumstances that cause water to enter the tunnel. At this time, the engineers of the undersea tunnel already had measures to deal with it. First, they would immediately close the inlet and turn on the tunnel's fire pumps to drain the water out of the tunnel and out of the tunnel through wastewater outlets placed throughout the tunnel.

Defects in the design of the submarine tunnel can lead to water ingress.

Even with adequate drainage systems and emergency treatment measures in place, the undersea tunnel may be at risk of water ingress. This can be due to flaws in the tunnel design, such as insufficient reinforcement of the tunnel or insufficient strength of the material in which the tunnel is a major part of the construction project. If such a problem occurs, the undersea tunnel will experience severe flooding, which will threaten the safety of the tunnel and people.

Conclusion. In general, the undersea tunnel is not afraid of water ingress because they have taken many measures to prevent seawater from seeping in, and they have a well-developed drainage system and emergency treatment measures. However, due to the lack of design and material requirements, there is still a risk of flooding in the tunnel.

Therefore, in the process of tunnel construction, it is necessary to pay attention to the reinforcement and sealing of the tunnel to ensure the long-term, stable and safe operation of the submarine tunnel.