The sea is full of water, so how did people build undersea tunnels?

China's Hong Kong-Zhuhai-Macao Bridge is the world's longest sea-crossing bridge, with a total length of 55 kilometers, of which there is a section of the road leading to the seabed, that is, the undersea tunnel, connecting two artificial islands, mainly to facilitate the passage of ships, plus it can be protected from the impact of the weather at sea, but some people are puzzled, the sea is full of water, how is the undersea tunnel built?

In fact, there are many ways to build undersea tunnels, but there are four methods that can be considered at present, namely drilling and blasting method, immersed tube method, roadheader method and shield method.

The first is the drilling and blasting method, just like the principle of mining, first blast out a certain distance, transport all the soil and stones out of the inside and then make a lining to prevent the tunnel from deformation or collapse, if there is water seeping out from the rock cracks, it needs to be grouting and blocking, and the cycle is repeated until the tunnel is opened. Because the power of explosives is very large, experts must strictly study the formation, and this method cannot be used if it encounters unstable formations. China's first undersea tunnel, Xiamen Xiang'an undersea tunnel, was built by this method.

The second is the immersed pipe method, which is to sink the sealed pipe at both ends of a section into the dug groove, and then connect each section of the pipeline with hydraulic crimping, and finally remove the sealing wall of the two sections, connect the overall tunnel, inject concrete, prevent water seepage, just like the water pipe, the waterproof work should also be done extremely carefully, there will be water leakage in the slightly poor pool, the Hong Kong-Zhuhai-Macao Bridge kilometer-long submarine tunnel is built in this way, with 33 sections of pipeline, covered with stones on the top and outside of it, to prevent the tunnel from floating up.

The third TBM method and the fourth shield machine method are similar, both use large mechanical drill bits to dig out the tunnel, the difference is in the geological environment, the TBM is mainly used to dig relatively hard rock, this looks like a big mallet is the TBM.

The shield machine is used in the soft mud, the shield machine is relatively good, it can be waterproof, easy to deal with the situation of water seepage during the excavation process, plus you can assemble concrete segments while excavating, the outer layer and segments to support the surrounding rocks, to prevent collapse, it can be said to be very versatile, the most used method in the construction of submarine tunnels is the shield method.

People wear wetsuits and masks to prevent them from choking on the water.

After 6 years of planning and 9 years of capital construction, the Hong Kong-Zhuhai-Macao Bridge has been gradually opened to traffic after 15 years. The total length of the overpass is 55 kilometers, and it not only has a road bridge section, but also a kilometer of tunnel, which is the longest immersed tunnel on the planet. How was the undersea tunnel completed at such a deep depth?

On a global scale, the infrastructure construction of the undersea tunnel originated in the 40s of the last century. In fact, there are many kinds of pavement of undersea tunnels, the common ones are drilling and blasting method and roadheader method, all of which are blown up into a distance with time bombs, and then slag discharged, and then blown up with ** objects, and so on, until the tunnel is fully connected. It is generally built in the deepest part of the deep-sea rock formation to prevent it from getting along with the sea.

And the immediate contact with the sea surface is the shield method and the immersed tube method.

The first is the popular shield method, which is used to treat soft foundations, during the construction of the project, the TBM is pushed in the geological structure, and at the same time, the surrounding soil is temporarily supported by the shield shell of the tunneling, and then the pipeline is paved little by little. Therefore, it is important that the moisture resistance of each segment and the preset specifications of the pipe are measured precisely and precisely. The shield method does not jeopardize the route at all, and can build longer and deeper undersea tunnels.

Naturally, this method is only suitable for tunnels with low pressure and small spans, such as the Yangtze River Tunnel.

The second is the immersed tunnel, to put it bluntly, it is to sink the pipes into the sea one by one, and the Hong Kong-Zhuhai-Macao Bridge is the way used. The tunnel is concreted in advance, and the pipe is then hoisted into a specific part of the sea by a gantry. The front and back are connected in a flat row, and finally the earth is backfilled with earth (stone), so that the undersea tunnel is completed.

Don't think that this method is very simple, but the difficulty coefficient of engineering construction in the seabed is still very large, and it is not allowed to make a mistake of one centimeter, otherwise it will endanger the whole. From this point of view, I can't help but feel the excellence of my country's construction projects.

Generally, it is necessary to overcome many difficulties, and when laying tunnels, the tunneling method or this is the drilling and blasting method, which pre-embeds explosives in advance, and then blasts out the rocks of this place, and then uses such equipment technology to excavate, and will achieve accurate measurement in the process of building the pre-construction.

The seabed will be surveyed, then a tunnel will be dug underground, then materials will be transported through the tunnel for installation, and finally all the soil on the surface of the hungry locust outside the tunnel will be removed, so that the underwater swimming tunnel will be completed.

One method is to use a very powerful excavator, and the other is to use the immersed pipe method, using a very large shock hammer on the sea to sink the prepared cement pipe into the sea and then install it by the workers.

The section will be excavated using drilling and blasting, and then the construction will be carried out, first a profile will be designed, and the construction will be carried out using the immersed pipe method.

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.

There are four main construction methods for the excavation of undersea tunnels.

Drill and blast method. It is mainly used to excavate the section by drilling hole blasting method and the construction method of Peiyanzhao to build tunnels and underground works. When the drill and blast method is used, the entire section is excavated to the design contour, and the lining is built accordingly.

The undersea tunnels that have been built and are under construction in mainland China, Xiamen Xiang'an undersea tunnel, Qingdao Jiaozhou Bay undersea tunnel, and Xiamen Haicang undersea tunnel are all constructed by mining method.

Immersed tube method. The immersed tube method is a construction method for building tunnels underwater. Immersed tunnels are going to be several.

The prefabricated sections are respectively floated to the sea surface (river surface) site, and one by one they are sunk and installed in the dredging foundation groove, and the underwater tunnels built in this method are constructed. A number of cross-harbour tunnels in Hong Kong are constructed using the immersed tube method.

TBM method. The TBM method is a method of excavating tunnels, roadways, and other underground spaces. Referred to as TBM (Tunnel Boring Manchine) method, the rock is sheared, extruded and crushed by special large-scale cutting equipment, and then the gravel is transported out through supporting transportation equipment.

The Channel Tunnel, which connects the UK and France, was excavated using the TBM method.

Shield method. Shield meceod is a fully mechanized construction method in the construction of the dark excavation method, it is to advance the shield machinery in the ground, prevent the collapse to the tunnel by supporting the surrounding rock through the shield shell and segments, and excavate the soil with a cutting device in front of the excavation at the same time, transport out of the hole through the excavation machinery, press the jack in the rear by jacking, and assemble the precast concrete segments to form a mechanized construction method of the tunnel structure. The Tokyo Bay Undersea Tunnel in Japan was constructed using the shield method.