Part1 Mountain Tunnel (Drilling and Explosion Method)
Just the tunnel project practitioners, non-built tunnel is how few words can be said clearly, different tunnels in different ways, such as mountain tunnels, subway tunnels, construction methods undersea tunnel huge difference. In order to facilitate the public understanding, I have taken several typical construction methods in the construction of mountain tunnels, subsea tunnels and subway tunnels as examples. The key steps are taken in general, and some specific refinement steps are omitted directly. Professionals do not spray.
First, do the hole
As shown in the figure above, first build the tunnel arch according to the designed position, and then pour the concrete. Then enter the large pipe shed, which is the row of steel pipes above, the length of 10-30 meters depends on the situation. After the injection, the high pressure is injected into the cement slurry. The advantage is that the soil is cemented with the steel pipe cement slurry to form An arched reinforced soil. When you dig this way, you won't be embarrassed.
Second, digging the body, doing the first layer of support
When the tunnel is dug, different methods are selected according to the quality of the rock. The size and method of digging are different. Specifically, if it is a hard and complete rock, how big the tunnel can be dug, if it is the soil like the above picture, it will score three or four to dig. This is a tunnel in the Xinchengkun line. It is divided into four parts to dig. Now I see the left side, the lower left, the upper right, and the lower right to be dug.
In general, the rock tunnel will not smash immediately after it has been dug, and the soil tunnel will not smash immediately due to pre-grouting or anchoring (that is, thick steel bars). At this time, the workers will follow the measurement instructions. , put some steel arches that are pre-formed into the tunnel outline to the designated position,
After the steel arches are placed, the gap between the two arches should be placed with steel mesh, welded, and the anchors must be driven laterally. After that, it is necessary to spray concrete.
After the concrete is sprayed out, it will stick to the steel frame, so that the steel frame and the rock and coagulation of the tunnel form a whole and are collectively stressed. At this time, the whole tunnel is like this:
Of course, my tunnel pictures are all found online, not the same tunnel. So look different. The tunnel above is very obvious, it is excavated in two parts. The tunnel is generally supported by two layers. The first layer is like the one above. After the shotcrete is applied, it has a certain stability ability, and it will not be embarrassing for a long time. But the tunnel has to go on the next step if it doesn't matter if it doesn't go wrong for decades.
Third, do the second layer of support
This step is similar to our bridges and buildings, that is, reinforced concrete is used. Therefore, it is necessary to tie the steel bars and lay the waterproof boards inside. After all, the tunnel waterproofing work in the mountains is very important.
The shiny inside of the dense steel bars is called the waterproof board. These steel bars are the workers standing on this table and tying them one by one. After the steel bars are done, the concrete is poured. How did the concrete go to the wall? It’s time for the big guy to play:
This guy is called a two-lined trolley with its own vibration function. After the previous process is completed, it is pushed forward. There is still a gap between the entire trolley and the tunnel wall, and we seal both ends. The concrete is injected through the pipe on the platform body and automatically vibrated to make the secondary support of the tunnel, which is the final support. The pouring process is as follows:
After the concrete is poured, the mold can be demolished after the specified curing time, and the trolley can be driven away. In the end, he became the following picture. This way, because it forms a closed stable structure, it will not collapse like a bridge. The earthquake is not afraid.
The main structure of the tunnel is thus completed. This is followed by the construction of tunnel pavement, drainage, ventilation, lighting, power supply and distribution, and safety. It will not be repeated here. These are the most common excavation processes for mountain tunnels.
Part2 Undersea Tunnel (Sinking Method)
I don’t think that the enthusiasm that everyone likes is so high, then I will update the most commonly used immersed method in the Undersea Tunnel. The so-called immersed method, the violent explanation is to pre-form the tunnel on the ground and then sink to the bottom of the sea. I also said in three steps.
First, prefabricated immersed pipe
The tunnel is very long. Of course, we can't do a whole. We usually pre-fabricate one section and then dock it. Take the Hong Kong-Zhuhai-Macao Bridge undersea tunnel as an example. One immersed pipe is 180 meters long and weighs 10,000 tons. Even if we make it, we can't move it. What should I do? Then dig a large pit on the land near the sea and pre-fabricate the section inside.
After prefabrication, because it is too heavy and there is no mechanical transport, first plug the ends of the immersed tube and put the water in.
After blocking, release water:
Of course, the top and bottom maps do not correspond, so everyone understands. The prefabricated immersed tunnel is ready to be transported to the designated location. Before we can, we still need to do one thing.
Second, the base trench excavation
Since the surface of the seabed is all muddy, the foundation must be completed before sinking the pipe, and the surface mud is cleaned with special equipment.
Of course, what kind of seabed is we can't see, but there are dedicated video surveillance equipment in actual operation, which will not be discussed here. After removing the sludge, depending on the basic conditions of the seabed, it may be necessary to use compacted sand piles, ripraps, etc. to make the foundation dense.
Ok, the bottom of the sea can't see it, use the animation to take a screenshot... After the basics are done, the next step is taken.
Third, sink pipe op amp, underwater docking
Drag the immersed tube to the designated location, sink it, and monitor it in real time according to various high-precision monitoring equipment during the sinking process to ensure accurate docking of the two immersed pipes. This is a very difficult part of the immersed tunnel construction and a key step in testing various technical levels. After docking, the joints should be waterproofed, poured concrete, and then backfilled with soil. This is the main construction process of the immersed tunnel. The details of the treatment, welcome everyone to point out in the comment area
Part3 City Subway Tunnel (Shield Method)
Many people are talking about shields, so I will write them together. The shield method is actually a kind of TBM tunneling method, but the soft rock area is used to call it a shield. The shield method has a wide range of applications in urban subway tunnels, across rivers, across rivers, and across sea tunnels. Shield machine is a very expensive equipment. It is said that the domestic price is more than 20 million. I can't imagine it in Japan and Germany.
The front is the cutterhead, which cuts the rock or soil and transports it to the rear and is transported away by other means of transport. I still have three steps to say.
I. Starting well construction, shield downhole
Because the subway tunnel is buried underground, when constructing with a shield, you need to dig a pit from the ground, install the shield machine, and then dig. Because the pit is deep and easy to collapse, there are many measures to be used to strengthen the support.
When the pit is dug to the designated position, the shield machine can be installed and debugged.
Second, shield tunneling, segment installation
Shield construction is different from drilling and blasting method. Its lining is divided into one piece, factory prefabricated, prefabricated, transported to the site for splicing. So before you dig, you have to do the piece:
These are the shield segments, and the entire subway tunnel is assembled by them to support O(∩_∩)O~
When the shield machine digs in, the front is the cutter to cut the soil, and the back is the jack press to make it advance. The cut soil is mechanically transported out of the hole, which is probably like this:
Of course, every time you dig a little distance, the workers will install the segments and support the soil to ensure safety.
Third, the receiving well is reinforced and shielded into the well
There is nothing to say in this step. The receiving well is reinforced and waiting for the shield machine to come in. The shield machine breaks out. Is there any point of vision of the sci-fi film? The process of the shield tunnel is basically like this. After that, the shield machine was dismantled and hung up. As for the two big pits, the decoration and decoration became a subway station~
The above is the main process of various tunnels. It should be pointed out that the drilling and blasting method is not only used in mountain tunnels, but also widely used in subway tunnels and undersea tunnels. The shield method is also often used in various rivers and rivers. Tunnels, these three methods basically cover the construction methods of various tunnels. Once again, it is not rigorous for professionals to use as a non-professional literacy sticker. Please study it yourself. Find a picture hard, give it a compliment. O(∩_∩)O~~
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