From the reef to the island, the southernmost village
Ten years of reefs turned into land, and once the waves turned into villages. When the largest island in the South China Sea was changed from Woody Island to Mischief Island, Mischief Village also became the southernmost administrative village in the country.
In the past 10 years, the giant atoll-shaped reef has been transformed into a leafy island land, where there are no traces of previous reclamation, and the total area of Mischief Island is nearly 6 square kilometers, including the gateway islet of Mischief Island.
After this series of changes, the reef became an island, and the inner side of the atoll seemed to become an inner lake. Nankojima, which is a few kilometers away from Mischief Island, has become the "South Gate" of Mischief Island, which guards a waterway in and out.
The reef becomes an island and the sea becomes a lake, and ships enter and exit to guard the portal. If we say that the power of nature is the vicissitudes of the sea, it is the changes of sea and land over hundreds of millions of years. The changes in Mischief Island and even the Nankai Islands have exceeded the power of nature for 10,000 years in about 10 years.
So, what is this artifact that can transform land and sea?
It takes two weeks to create an artifact for the island
The method of land reclamation is not to carry soil, sand and gravel from the land as people imagined, but to take local materials from the bottom of the ocean. The tools used on land are excavators, and "digging boats" are also needed in marine work.
How does this type of vessel work? Sediment is rolled out of the seabed and piped to the area. If the seabed is just sediment, ordinary mechanical devices will do the trick, but there are often a lot of rocks in the depths of the ocean, and much more powerful equipment is required to turn these rocks into debris for dredging.
It was against this background that the dredger that could walk in the ocean was born. It has a huge output power and has a strong sucking capacity for mud and sand rocks. It is the Tian Kun, the largest working ship of its kind in Asia.
The Tian Kun works on a huge and rigid reamer with a diameter of 3.15 meters and a maximum output of 6,600 KW. The working principle is drill and cut, and all rocks have to be deformed under its blade.
The reamer is only one of the main components of the Tiankun, and in order to operate smoothly in the sea full of wind and waves, the hull must also be stable. This one relies on giant steel piles that can be driven into the seabed.
There are two of them, each of which is more than 55 meters long and weighs more than 183 tons. When the steel pile was wedged into the seabed, the Tiankun was firmly established in the ocean. At this time, even if there is a 3-meter-high wave head-on, the Tiankun can work safely without dodging.
The steel piles are its two thighs, and with its blessing, the ship can move to any area for blowing and filling operations. Once you can stand firm and be able to consistently produce blow-fill material, it's time for the third major component – the transport pipe.
Above the reamer, there is a "blood basin mouth", and the suction power it produces is amazing. Fragments of sediment and gravel are cut from the seabed, and through this opening, they are sent to the conveyor belt.
The conveyor belt then has a huge pumping force to deliver the material to the designated blowing area. The longest conveying distance can reach 15 kilometers. When the work is started at the same time, the entire conveyor is operated by three mud pumps connected in parallel.
Industry insiders have said that its output power is like the power generated by two high-speed trains of Fuxing. There are sharp tools for cutting mud and gravel, steel piles to stabilize the body, and powerful conveying devices, relying on the whole system, the blowing and filling operation can be completed efficiently.
According to the efficiency of the Tiankun, the 250,000 square meters of artificial islands that Malaysia spent 30 years to build in the early years can be easily completed in only 14 days. However, it is such a sharp weapon, and the mainland was also controlled by others in the early years.
4 tons of gold to buy an operating vessel
The dredger sounds like a pretty rustic thing, but if you want to use it efficiently in the operation scene, you need high technology and intensive financial support. In particular, heavy dredgers are not only used for land reclamation, but also for dredging of waterways and port excavation.
In the middle of the 20th century, only a few countries in the world, such as Belgium and the Netherlands, mastered the core construction technology of dredgers. Countries with technology not only monopolize bargaining power, but also ships and accessories themselves belong to strategic equipment and are managed in a unified manner. In other words, other countries may not be able to buy it if they want to spend money.
Domestic river dredging and port excavation operations began in Tianjin, but over the years, about 90% of the engineering vessels we used were imported, and everything had to be controlled by others.
Once upon a time, in the 60s of the last century, there was a need for a self-propelled rake suction ship, which was eventually purchased from the Netherlands, and the equivalent of 4 tons of gold was spent to buy this ship.
Paying a high price to buy someone else's stuff not only can't figure out the doorway, but the equipment that the other party sells you is not the most advanced product. However, it is not possible to achieve independent production and technological innovation.
However, the actual situation facing the country determines that our ships can only be built on their own, and only in this way can we really break through the blockade. As a result, the Sky Whale, which was originally designed and manufactured by foreign countries and manufactured in China, was born in advance.
It belongs to the cutter suction operation, and its cutter has an output power of 4200 kilowatts. It is precisely because there is a sky whale that there will be a subsequent sky kun. The two sister ships are both invested and built by CCCC Tianjin Waterway Bureau.
As a younger sister, Tian Kun has realized domestic design to domestic construction, and all technologies have complete intellectual property rights. With its later display of power in the South China Sea, it marked the mainland's thorough mastery of equipment and technology in the fields of land reclamation and dredging of waterways.
1 football field can be filled in 1 hour
The domestic breakthrough in technology is all-round, Tian Kun not only has a strong power, but also has a perfect intelligent control system. Compared with the brainless operation of the dredger in the past, this domestic weapon can calculate the situation of the operation area in real time in the process of operation.
At the same time, the work efficiency of the Sky Whale is not inferior to that of the Sky Kun. 4,500 cubic meters of sediment and other materials can be exported 6 kilometers in 1 hour. The workload in one day can easily reach 100,000 cubic meters. The seabed mixture excavated per hour is capable of filling 1 standard football field.
Of course, the power of the Tiankun is even greater in comparison. The power of the reamer is 6,600 kilowatts, the excavation volume can reach 6,000 cubic meters per hour, and the maximum excavation depth can reach 35 meters.
With strong power, whether it is sand, silt or rock, it can be excavated in front of its powerful reamer. It is precisely because of the strong power that the annual dredging capacity of the mainland exceeded 1 billion cubic meters in 2018.
In addition to domestic operations, two other dredgers produced by the mainland, Tongyuan and Tongxu, also went to the port of St. Petersburg for construction in 2015, which is also the first time that a domestic company has contracted a dredging project in Europe.
In addition to participating in engineering operations in Russia, in recent years, our dredging ships have also participated in a variety of projects in Pakistan, Malaysia, Ukraine and other countries.
Just like the islands that have sprung up in the South China Sea in the past 10 years, the mainland's dredging engineering ships have also accumulated and made their own name in the past ten years.
And according to the announcement of the Ministry of Commerce in 2017, dredgers are large-scale controlled equipment and cannot be exported without permission. From the previous sky-high price to the current ability to produce and complete a series of major engineering operations by ourselves, the process from scratch confirms our technological progress.
Returning to the issue of land reclamation, while there are technologies and equipment, let's take a look at the principles and steps of its realization.
There are 3 main processes of blow-filling
The traditional way of land creation is to obtain raw materials from the land area, whether it is stone or earth, etc., and finally obtain a large area of land. In contrast, the blowing method is more cost-effective and time-saving, and is the most efficient compared to the traditional method.
The method has three important process steps in the course of the job.
The first is the sand quilt, which is arranged in the operation area, specifically the sandy soil and silty soil materials filled by geotextile bags. The sand quilt needs to be arranged in multiple layers in the operation area, which can quickly form a whole and has toughness, and can adapt well to the deformation of the seabed.
The weight of a single bag of sand quilt can reach tens of tons or even hundreds of tons, and it can evenly distribute the pressure in the substrate of the seabed, which can play a role in tide resistance and stability. In addition, the pressure can also squeeze the flow mud on the sea surface to the two sides of the area, and the geological environment of the entire operation area is improved.
The second is the embankment. After the sand cover layer is constructed, the next step is to build an embankment in the operation area, usually bagged sand or rubble. In contrast, bagged sand has better impermeability.
Moreover, in the process of operation, the operation of bagged sand can realize mechanization and large-scale operation, which not only shortens the relative construction period, but also lowers the cost. In addition, the material required for bagged sand is the same as the material of the sand quilt, so that the continuity of the whole project can be enhanced.
Finally, there is the blowing. Depending on the construction area, the materials required for this phase of the project are different. For example, some operation areas are sand blowing to create land, and some are blowing and filling silt.
If it is a land reclamation of silt, it is necessary to obtain the nearby silt and mix it with seawater into a slurry according to a certain proportion, and then according to the normal operation process, through transmission and blowing, the silt will finally consolidate in the operation area, and finally form a land higher than the water level.
The other is sand blowing to create land, and the material it needs is sand and gravel. This also depends on the composition of the materials in the operation area, but the cost of sand blowing is relatively high compared to blowing silt. The specific type of material to be used is determined comprehensively according to the nature of the land and the situation of the area.
epilogue
There is a story of Jingwei's reclamation in ancient mythology on the mainland, and Jingwei wants to fill the turbulent waves with his own strength, and his determination and courage are commendable. Today, whether we are in the South China Sea or in the offshore area, all the blowing and filling operations are comparable to the feat of Jingwei in the past.
On an island like Mischief Island, the blowing and filling operation is only the first step. After the planning of the administrative area, the fishermen are retained all year round, and the natural ecological environment of the island is gradually established and a more stable organism is formed, which is the foundation for the subsequent "survival" of the island.
In the same way, technological progress is the premise for all this, and technological progress is also the starting point for changing and establishing new ideas. Everything is prosperous because of technology, and everything is as unswerving as Jingwei reclamation. With these two points, the waves of the sea can also surrender in front of the land.
Resources:
"The New Generation of Island-Building Artifact "Tian Kun" Is Refined in This Way", Economic Information Daily, May 29, 2018