Reborn Tech Scholar

Chapter 381 Bohai Tunnel Planning Meeting
At present, the longest undersea tunnel in the world is the Seikan Subsea Tunnel built in the Tsugaru Strait of the island country, with a total length of 53.85 kilometers. It took 1964 years before and after its completion in 1987. The main tunnel of this tunnel has a total length of 23 kilometers, of which the subsea part is 53.9 kilometers, the road part is 23.3 kilometers on the Honshu side, and 13.55 kilometers on the Hokkaido side.The tunnel was completed and opened to traffic, ending the history of sea transportation between Dongying Honshu and Hokkaido.

For a long time, the Seikan Submarine Tunnel has been the pride of Japan's architectural history. It is regarded by Japan as a symbol of high-tech technology. Like Japan's high-speed rail, it has been constantly publicized.

And there is no doubt that once the Bohai Sea Tunnel is put into operation and completed, with its length of more than 100 kilometers, it will surpass the Seikan Tunnel and become the world's largest undersea tunnel.

At that time, Huaxia's achievements in infrastructure construction that have attracted the attention of the world will inevitably have a Bohai Tunnel!After all, in terms of the difficulty of construction, this Bohai Sea Tunnel will still be on top of the Hong Kong-Zhuhai-Macao Bridge.

Qin Yuanqing checked the information and found that the Bohai Tunnel Project is really a national-level huge project with a planned investment of 2000 billion yuan. It can be said that this is probably the largest investment amount ever seen in a single project. After all, the Three Gorges Dam back then The total project investment is only about 900 billion yuan. The reason why the static total investment of the Three Gorges Project reaches 2000 billion yuan is because it includes resettlement, land acquisition and so on.

Just like the Hong Kong-Zhuhai-Macao Bridge, which is still under construction, it is estimated that the total cost will be almost 1000 billion when it is completed.

That is, the investment in the Bohai Tunnel is enough to build two Hong Kong-Zhuhai-Macao Bridges.

Moreover, 2000 billion yuan is only an estimated investment. It is common for such large-scale projects to increase investment in the later stage. Maybe the final total investment will be 3000 billion yuan or even 4000 billion yuan.

One of the most important reasons why the cost is so high is that the construction of subsea tunnels is difficult and technically demanding, and the cost is naturally much higher than that of bridges.

"The country is really getting bigger and bigger now, and the big money is starting to use 2000 billion yuan as the cut-off point!" Qin Yuanqing said secretly.

The investment of the three large-scale hydropower stations in the Yarlung Zangbo River Basin is also 2000 billion yuan. Although there are various disturbances, in the face of Huaxia's firm attitude and absolute strength, the three large-scale hydropower stations are still in the construction stage.The investment for ten third-generation nuclear power plants is actually based on 2000 billion yuan as the starting point.

Now, add this Bohai Tunnel plan!

These large-scale infrastructure projects are undoubtedly dominated by state forces. It is impossible for private companies to invest in such projects with a long construction cycle and a long cost recovery cycle, and the construction technology is basically in the hands of state-owned enterprises.

So don't always scold state-owned enterprises. State-owned enterprises are indeed doing a lot of things for the national economy and people's livelihood.

In the evening, a car came to Shahe Campus to pick up Qin Yuanqing. After some identity verification, Qin Yuanqing got into the car. After arriving at the airport, he met his superiors and came to Yancheng City.

At 9:00 the next morning, when Qin Yuanqing and the leaders entered the venue together, he glanced at it and immediately understood the country's determination. If there is no accident, the Bohai Tunnel Project will be launched.

Look at the expert group this time, apart from Qin Yuanqing, there are ten academicians of the Chinese Academy of Engineering and seven academicians of the Chinese Academy of Sciences!
In the meeting room, when the others saw Qin Yuanqing accompanying the leader into the meeting room, they all showed surprise, and then they all showed thoughtful looks.

The host of the meeting, a leader from Lu Province, introduced the expert group. In addition to as many as 58 academicians, there are also 79 professors from various universities, 200 professor-level senior engineers, and the presidents of large state-owned enterprises such as China Railway Tunnel Group. There are more than [-] technical experts in the conference room, such as engineers and deputy chief engineers.

Everyone realized that this Bohai Tunnel Planning Meeting was different from previous meetings, and the specifications had been raised by more than two levels.

In the past Bohai Tunnel Planning Conference, academicians also participated, but it was probably two or three, three or four. Most of the people who presided over the meeting were local city leaders, but this time it was the relevant leaders of Lu Province who presided over the meeting, and there were even higher levels. The leaders of the leaders attended the meeting, and even Qin Yuanqing, a banner figure in the field of scientific research in China, came to the meeting.

It seems that after so many years of deliberation, the superiors are finally getting serious about the Bohai Tunnel Project.

Take a look at this meeting room. Among the technical staff, every one is at least a professor-level scientific research worker or engineer. Associate professors and senior engineers are not eligible to participate.

Qin Yuanqing watched the technicians discussing one by one, and took notes carefully. The technicians who participated in this meeting had participated in the Bohai Tunnel Project for a long time in the early stage, and they knew much more about the Bohai Tunnel Project than him. Thoughts on the tunnel plan.

This meeting is also a collision of sparks of thinking and wisdom.

Due to the special geographical location of the Bohai Strait, all the transportation routes of various ports in the Bohai Sea pass through here. There are also giant ships of 20 tons and 30 tons that often come and go. , This has led to the fact that only subsea tunnels can be built in this place, and there is no possibility of building bridges.

Not to mention, the Bohai Strait is still an important military strategic location, and there are even aircraft carriers passing through it from time to time, so there is no possibility of building a bridge at all.

There are mainly three methods for the construction of subsea tunnels, namely, the submerged method, the shield method, and the boring machine method.

To understand it simply, the submersion method is to prefabricate a circular tunnel on the ground, then dig a trench on the seabed, and sink the tunnel into the trench.Finally, the sections of immersed tube tunnels are spliced ​​together.

The shield tunneling method and tunnel boring machine method use special machinery to advance in geological layers or rock layers, and then personnel inside the machinery splice pieces of concrete segments into tunnels.

The difference between the shield machine method and the boring machine method lies in the difference in the equipment used.The three tunnel construction techniques have their own characteristics and advantages and disadvantages.

For example, an academician advocated the use of the submersion method. The advantage of this method is that the construction difficulty is the least, the construction speed is fast, and the investment is the most economical.

But it was opposed by many people, because it is very simple. This area is within the scope of the Bohai Sea Marine Reserve. There are more than 30 types of benthic organisms living in this area, including 8 species of annelids, 11 species of molluscs, and arthropods. There are 15 species of animals, all of which are under national protection.Once the submersion method is used to construct the tunnel, it will cause a devastating blow to these protected organisms.

This is also the reason why it was much easier to build subsea tunnels and bridges in the past than it is now, because there was no awareness of environmental protection and animal protection before, but it is different now. If you dare not pay attention, then various international Environmental protection organizations and animal protection organizations will be in an uproar, and some countries will make bad things behind their backs. At that time, the international influence will be very bad. Maybe halfway through the construction, the project will be abandoned due to the huge international public opinion, causing huge losses.

China is a responsible big country, and it is impossible to ignore it like some countries do.

Therefore, this submersion method was rejected, and of course a detour can also be made, but the mileage of this detour will have to be doubled, and the project investment will also double.

At that time, it is estimated that 4000 billion yuan will not be able to beat it.

This Bohai Sea Tunnel meeting lasted longer than ever before. It lasted for three full days. All parties conducted full discussions in terms of theory and actual construction. Combination of burial methods.

After all, simply using the shield method or tunneling machine method has a big flaw, that is-expensive!

In the construction of short-distance subsea tunnels, this gap is not very obvious.However, the longer the construction length of the subsea tunnel, the more obvious this gap will be. Whether it is in terms of materials or labor, the cost of money will gradually increase with the increase of the length.Using this method, 2500 to 3000 billion may not be enough. If weak formations or special circumstances are encountered, the cost will be further increased.

Moreover, the shield tunneling method and the boring machine method have many construction difficulties, and the technical requirements are much higher than those of the submerged method.For the buried method, as long as the butt joint of the immersed tube tunnel is properly handled, everything will be fine.However, the shield method is different from the tunnel boring machine method. There are no major difficulties, but there are a lot of small technical difficulties.

For example, when using equipment to dig a tunnel, how to ensure that the surrounding soil and rock layers do not collapse and become unstable.When the equipment is propelled forward by the thrust of the jack, how to control the total thrust of the equipment so that the front soil will not move forward and bulge due to extrusion due to excessive thrust, and the propulsion speed will be affected by too small thrust.

Wait, wait, there are a lot of difficulties.

Moreover, due to the different geological conditions of each sea area, it is impossible to learn from other completed projects for these technical difficulties.

In the end, an academician proposed that the method of combining the submersion method and the shield method should be adopted, and the submersion method should be selected for places where the submersion method is allowed, and the shield method should be selected for places where the submersion method is not allowed. The submersion method is higher, but it is within the acceptable range.

However, this way of combining each other is not without problems. The biggest problem is the connection between the tunnel section constructed by the shield method and the tunnel section constructed by the submerged method. After all, the specifications of the tunnels obtained by the two construction methods are different, and one is built under the seabed. , one on the bottom of the sea, how to connect?

This kind of detailed connection is not as simple as CAD drawing, it needs to be practical, otherwise it will be meaningless.

During the discussion at the meeting in the afternoon, none of the people came up with a feasible solution. Even those academicians were frowning and thinking sadly. They also proposed some solutions, but they were theoretical, but the actual construction was not Very difficult, almost impossible to do.

　I saw a book friend mentioned that the car can already be boarded and transported to the other side by ship.This is different from building tunnels and bridges. Just like when Ningbo went to Zhoushan in the past, the car was also driven on a boat, and then transported to Zhoushan by boat. Why did Ningbo and Zhoushan need to build a cross-sea bridge?It is to speed up the transportation speed and transportation volume!Turnover by boat, always limited!
　　
　
(End of this chapter)