JPH08232251A - Method for constructing artificial island - Google Patents

Abstract

PURPOSE: To provide a method for constructing a large artificial island such as an airport island on the sea for effective use of space. CONSTITUTION: An inverted T-shaped unit A, wherein a horizontal base part 1 and a vertical wall part 2 rising vertically from the center position of the base part 1 are formed into an inverted T-shape with a hollow air chamber 3 provided inside its skeleton and equipped with an air vent plug 4, is fabricated on the ground. The seabed 6 at the construction point of an artificial island is leveled horizontally. After the inverted T-shaped unit A is towed to the construction point, the air vent plug 4 is opened, and the base part 1 is landed on the seabed 6. Floor plates 5 are formed on the surface 7 of the sea over the vertical wall part 2. Fabrication of the inverted T-shaped unit A and the like on the ground results in reduced marine operations and contributes to enhancing operability and safety and reducing construction period while preserving the ecosystem underwater.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing an artificial island on the sea so that space can be effectively used, and more specifically, it is large enough to be used for airports, leisure lands, etc. The present invention relates to a method for easily constructing an artificial island.

2. Description of the Related Art Taking advantage of the momentum of recent waterfront plans and the like, there is an increasing demand for constructing artificial islands on the sea so as to effectively utilize the sea space. Currently, there are four known methods for constructing artificial islands on the sea: landfill type, pier type, floating type, and soft landing type. The landfill type is a method of constructing an artificial island by landfilling landfill materials such as seabed sediment and land-based sediment in the sea area partitioned by the revetment structure. Four
Most practiced of the methods. The pier type is also called a pile type, and is a method of embedding multiple steel piles, such as steel pipe piles and PC piles, which are support piles, in the seabed, and supporting the artificial ground floor slab at the upper end (pile head). . In connection with this construction method, the applicant has filed Japanese Patent Application No. 5-2 illustrated in FIG.
No. 36166 (Other, Japanese Patent Application No. 6-316408, etc.)
We have applied for a patent for the pile-type artificial ground. A set of two oblique piles a is deeply embedded until it reaches the support layer c of the seabed, and the artificial ground b is installed on the pile head of the oblique pile a to construct an artificial island for use at a maritime airport. There is. The floating body type is a method in which a floating body structure that becomes an artificial island is built on land in advance, and the floating body structure is towed to a construction position on the sea and floated as an artificial island on the sea. This is a method in which the floating structure is not fixed to the sea bottom considering seismic isolation. The soft-seated bottom type is a method of making prefabricated structures such as boxes on the seabed to make artificial islands. This is a method that has demonstrated its potential. Therefore, it is easy to apply to soft seabed.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The collection of earth and sand (mountain sand) is an environmental problem as it destroys nature. Even when seabed sediment is collected by dredging, seawater is polluted and the sea ecosystem is destroyed. In addition, it takes time for the landfill soil to stabilize, and in the long run, there will be the problem of differential settlement. In addition, land reclamation will adversely affect the marine ecosystem. In the pier type, it is very troublesome to install long support piles to reach the support layer on the bottom of the sea for offshore work, and it is dangerous and easily affected by the weather.
In addition, the cost is high when constructed with steel pipe piles. In particular,
When used on an airport island that requires durability of about 100 years, the cost for rust prevention is too high. In the case of building with PC piles, there is also a problem that the design criteria for long piles (about 50 to 60 m) have not been established. In the floating type, since the artificial island is not fixed to the sea floor, it is constantly affected by the waves and constantly swings. If it is in the inner bay, it is possible to reduce the influence of waves by putting a breakwater and put it into practical use. However, installing a breakwater will stop the flow of seawater, which will adversely affect the undersea ecosystem. In fact, the structural analysis of the soft-seed bottom equation has not been established yet. Seawater cannot be exchanged because the box or cylinder is sunk, and there is still an ecological problem. Therefore, the object of the present invention is not required to be a detailed design standard, the foundation part of the artificial island and the ground part (slab) can be easily constructed, and the workability and safety are excellent,
Moreover, it is to provide a method for constructing an artificial island that is gentle to the global environment, because the flow of seawater immediately under and around the artificial island does not adversely affect the undersea ecosystem.

As a means for solving the above-mentioned problems of the prior art, the method for constructing an artificial island according to the invention of claim 1 comprises: a) a horizontal base part 1 and a base part 1 A vertical wall 2 having a predetermined height rising vertically at the center is formed in an inverted T shape when viewed from the side, and has a hollow air chamber 3 inside the frame of the base 1 and the vertical wall 2 and an air vent plug. 4 to produce the inverted T-shaped unit A on land, b) to horizontally level the seabed 6 at the construction point of the artificial island, and c) to construct the inverted T-shaped unit A on the artificial island. Tow to the construction point, open the air vent plug 4 after reaching the construction point, and land the base 1 on the seabed 6, d) Vertical wall after finishing the inverted T-shaped unit A A slab 5 is formed on the sea surface 7 above the section 2 to construct an artificial island. To be characterized, respectively. The method for constructing an artificial island according to the invention of claim 2 comprises: a) a horizontal base part 1 and a vertical wall part 2 of a predetermined height rising vertically to the central position of the base part 1 in an inverted T shape when viewed from the side. To manufacture the inverted T-shaped unit A on the land, which has the hollow air chamber 3 inside the frame of the base 1 and the vertical wall 2 and the air vent plug 4 is attached, b) Adjacent The inverted T-shaped units A, A are arranged in such a manner that the vertical wall portions 2 and 2 are staggered by changing their directions by 90 degrees so as to be orthogonal to each other, and a desired number of the inverted T-shaped units A ... C) horizontally leveling the seabed ground 6 at the construction point of the artificial island, d) towing the artificial block for each building block S to the construction point of the artificial island, and after reaching the construction point. , Open the air vent plug 4 of the inverted T-shaped unit A , Thereby landing the base portion 1 to the seabed 6, e) after finishing the desired number of building block S ... sinking of sea level above the vertical wall 2 of the inverted T-shaped unit A 7
Forming the floor slab 5 on the top to construct an artificial island, respectively. The method for constructing an artificial island according to the invention of claim 3 is the floor slab 5 on the vertical wall 2 according to claim 1 or 2.
Is formed of precast concrete or cast-in-place concrete.

Operation: An inverted T-shaped unit A having a base portion 1 forming a base portion and a vertical wall portion 2 and having an air chamber 3 inside the body.
Can be easily manufactured on land using existing technology (Fig. 2). When constructing a large artificial island as shown in FIG. 1, by joining the relationship between the adjacent inverted T-shaped units A and A to each other in an orthogonal arrangement in which the vertical wall portions 2 and 2 alternately change their directions by 90 degrees. , The assembly block S is easily formed (FIG. 3). Since the inverted T-shaped unit A has a hollow structure and a large buoyancy, it can be towed on the sea. The inverted T-shaped unit A or the assembly block S, which has reached the construction point of the artificial island, can easily construct the base portion of the artificial island only by landing the base portion 1 on the seabed 6 (FIG. 4). Since the horizontal base 1 has a wide bottom surface and the ground pressure is dispersed, it is small,
The demand for bearing capacity of the seabed 6 is low and the stability is good. In addition, since the seabed 6 at the sunk location is leveled in advance, there is no terrain and differential settlement is prevented. The upper portion of the vertical wall portion 2 of the inverted T-shaped unit A that has been sunk protrudes above the sea surface 7 (Fig. 4), and on the vertical wall portion 2, a slab made of precast concrete or cast-in-place concrete is used. 5 can be easily formed, and it will be an artificial island land. In the large-scale artificial island, the adjacent inverted T-shaped units A and A are arranged orthogonally to each other, so pollution and stagnation are eliminated without obstructing the flow of seawater between the vertical walls 2 and 2 It is able to maintain the ecosystem of, and effectively resist horizontal forces such as earthquakes (Fig. 1).

Embodiments of the present invention shown in the drawings will be described below. FIG. 1 shows the whole of a large artificial island (mainly the structure of the foundation part) constructed on the coast or offshore at a water depth of about 20 m in order to effectively utilize the sea space. This artificial island will be used for large-scale offshore facilities, large-scale marine facilities, large-scale leisure land, and residential areas as well as maritime airports. Reference numeral A in the figure is a single inverted T-shaped unit that constitutes the basic part of the artificial island. Reference numeral 5 is a floor slab that constitutes the land portion. Code 6
Indicates the seabed, and reference numeral 7 indicates the sea surface. This artificial island is constructed by the following method. First, a plurality of inverted T-shaped units A shown in FIG. 2 are manufactured on land. The inverted T-shaped unit A is composed of a horizontal base portion 1 and a vertical vertical wall portion 2 which is slightly tapered upward and is made of precast concrete. The base portion 1 is formed into a large square having a length and width of about 20 m and a thickness of about 2 m, and the base portion 1 has a width of about 20 m and a height of about 2 m at the central position.
A vertical wall portion 2 having a thickness of 0 m and a thickness of about 2 m stands upright and is formed in an inverted T shape when viewed from the side. Base 1
Also, an air chamber 3 for reducing the weight is provided as a hollow structure inside the frame of the vertical wall portion 2.
A plurality of air vent plugs 4 for adjusting the inner hollow state are attached to the upper surface of the base portion 1 and the side surface of the vertical wall portion 2. In addition,
Although illustration is omitted, it is also possible to form an uneven shaki on the lower bottom surface of the base portion 1 to increase the resistance of the bottom surface portion against a horizontal force. In that case, the submerged state on the seabed 6, which will be described later, becomes strong. Further, the inverted T-shaped unit A can be manufactured not only of precast concrete but also of steel, and in this case, it is preferable that the surface of the steel material is subjected to rust prevention treatment. In the inverted T-shaped unit A, a plurality of building blocks S (see FIG. 3), which are aligned in the vertical and horizontal directions and joined, are formed in a land-based manufacturing yard such as a dock of a large shipyard. However, when the inverted T-shaped unit A is used alone, it is of course unnecessary to form the assembly block S. The size of the assembly block S is such that the entire artificial island is divided into several pieces in the longitudinal direction. In the case of this embodiment, as shown in FIG. 3, the artificial island is divided into two, and one assembly block S has the inverted T-shaped unit A divided by 5 in the lateral direction.
15 pieces in the vertical direction are closely arranged and joined. At this time, the vertical wall portions 2 and 2 are arranged orthogonal to each other in the relationship between the adjacent inverted T-shaped units A and A, with their directions changed by 90 degrees. The adjacent base parts 1 and 1 are connected to each other by tightening the reinforcing bars or the anchor wires 9 (see FIG. 4). The base portions 1 and 1 may be joined to each other with some distance therebetween. Before and after the formation of the assembly block S, the seabed 6 at the construction point of the artificial island is leveled horizontally. The method of leveling the ground is to drop gravel from the sea and spread the gravel on the seabed 6 with the help of a diver or an underwater bulldozer. When the seabed 6 is weak, for example, D
By the CM method (registered trademark), the ground is improved by adding the cement slurry to the soft seabed 6 while mixing and stirring to solidify and stabilize it. Then, the building blocks S are towed one by one to the construction point of the artificial island. The inverted T-shaped unit A forming the assembly block S has a hollow structure with the air chamber 3 and has a small weight to generate buoyancy, and is towed with a small force.
After the assembly block S reaches the construction point, the air vent plug 4 of each inverted T-shaped unit A is guided while being guided by the crane ship.
The subassembly 1 is opened and submerged, and the assembly block S is sunk so that the base portion 1 lands on the seabed 6. Next, the second building block S is towed and set in the same manner as described above. When the second building block S is to be sunk, the outer end of the vertical wall 2 of the already sunk building block S is used as a guide (see the portion P indicated by a circle in FIG. 3A). It can be exactly set in a fixed position right next to the first assembly block S. After the assembly block S is sunk, that is, the construction of the foundation of the artificial island is completed, the artificial ground is formed on the upper surface of the vertical wall portion 2 of the inverted T-shaped unit A protruding above the sea surface 7, as shown in FIG. The barrel floor slab 5 is formed. The floor slab 5 is made of precast concrete with a thickness of about 50 cm and is hung by a crane ship. Floor slab 5
As shown in FIG. 4, the end portions of P are placed on the upper half of the vertical wall portion 2 and are respectively placed on the floor slab 5 and the vertical wall portion 2.
A pre-stress is introduced into the C steel wire 8 and the fixing member 10 at the upper end of the floor slab 5 firmly bonds them together. When the floor slab 5 is formed in an appropriate area, the mobile crane can be placed and run on the floor slab 5, and the remaining floor slabs 5 can be efficiently installed one after another. Although not shown, a half precast concrete slab with omni muscles on the upper surface is used.
It is also preferable to cast cast concrete to form the floor slab 5. When the artificial island is used as a maritime airport, since the floor slab 5 is formed over a square of several km, sunlight may not reach the sea surface 7 over a wide area. When it is desired to reduce the dark water surface directly under the artificial island, it is possible to easily deal with it by not providing a part of the floor slab 5. Thus, the artificial island is completed, but seawater does not flow down between the vertical wall portions 2 and 2 on the lower surface of the artificial island, and no pollution or stagnation occurs. Therefore, fish can freely pass or live between the vertical walls 2 and 2, so that the marine ecosystem is well preserved. Moreover, since the vertical wall portions 2 and 2 are arranged orthogonally to each other, they effectively resist the seismic force.

According to the method of constructing an artificial island according to the present invention, the inverted T-shaped unit A or the assembly block S is manufactured on land, and the work on the sea is performed by towing the inverted T-shaped unit A. Most of them are submerged, which greatly contributes to improvement of workability and safety and shortening of construction period. Further, the inverted T-shaped unit A submerged in the seabed 6 is stable and contributes to the construction of a high quality artificial island. Adjacent vertical wall portions 2 and 2 are arranged orthogonally to each other and good treatment of horizontal force such as an earthquake also contributes to quality improvement, and the permanent stability of the artificial island is maintained. Furthermore, the flow of seawater around the artificial island is smooth, and fish can freely pass or live between the vertical walls 2 and 2 under the artificial island to form a fishing reef, which preserves the marine ecosystem. , An artificial island that is kind to the global environment will be built.

[Brief description of drawings]

FIG. 1 is an overall view showing a completed artificial island.

FIG. 2 is a perspective view showing an inverted T-shaped unit.

FIG. 3A is a plan view showing the structure of an assembly block;
B and C are side views of A.

FIG. 4 is a cross-sectional view showing how to connect the vertical wall portion and the floor slab.

FIG. 5 is a perspective view showing a conventional example.

[Explanation of symbols]

 A Reverse T-shaped unit S Assembly block 1 Base part 2 Vertical wall part 3 Air chamber 4 Air vent plug 5 Floor slab 6 Seabed 7 Sea level

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[Procedure amendment]

[Submission date] February 28, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

[Title of Invention] Method of constructing artificial island

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing an artificial island on the sea so that space can be effectively used, and more specifically, it is large enough to be used for airports, leisure lands, etc. The present invention relates to a method for easily constructing an artificial island.

[0002]

2. Description of the Related Art Taking advantage of the momentum of recent waterfront plans and the like, there is an increasing demand for constructing artificial islands on the sea so as to effectively utilize the sea space. Currently, there are four known methods for constructing artificial islands on the sea: landfill type, pier type, floating type, and soft landing type.

The landfill type is a method of constructing an artificial island by landfilling a landfill material such as seabed sediment and land sediment in a sea area partitioned by a revetment structure. The most implemented of the four methods. The pier type is also called a pile type, and it is installed by embedding a plurality of support piles such as steel pipe piles and PC piles in the seabed ground.
This is a method of supporting a slab, which is an artificial ground, on the upper end (pile head). In connection with this construction method, the applicant
The patent application for the pile type artificial ground according to Japanese Patent Application No. 5-236166 (in addition, Japanese Patent Application No. 6-316408, etc.) A set of two oblique piles a is deeply embedded until it reaches the support layer c of the seabed, and the artificial ground b is installed on the pile head of the oblique pile a to construct an artificial island for use at a maritime airport. There is.

The floating body type is a method in which a floating body structure to be an artificial island is constructed on land in advance, and the floating body structure is towed to a construction position on the sea so as to float as an artificial island on the sea. This is a method in which the floating structure is not fixed to the sea bottom considering seismic isolation. The soft-seated bottom type is a method of making prefabricated structures such as boxes on the seabed to make artificial islands. This is a method that has demonstrated its potential. Therefore, it is easy to apply to soft seabed.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The collection of earth and sand (mountain sand) is an environmental problem as it destroys nature. Even when seabed sediment is collected by dredging, seawater is polluted and the sea ecosystem is destroyed. In addition, it takes time for the landfill soil to stabilize, and in the long run, there will be the problem of differential settlement. In addition, land reclamation will adversely affect the marine ecosystem.

In the pier type, it is very troublesome to install long support piles to reach the support layer on the bottom of the sea as a work at sea, and it is dangerous and easily influenced by the weather. In addition, the cost is high when constructed with steel pipe piles. In particular, when used on an airport island that requires durability for about 100 years, the cost for rust prevention is too high. When building with PC piles,
There is also a problem that the design criteria for long piles (about 50-60 m) have not been established.

In the floating body type, since the artificial island is not fixed to the sea bottom, it is constantly affected by waves and is constantly swinging. If it is in the inner bay, it is possible to reduce the influence of waves by putting a breakwater and put it into practical use. However, installing a breakwater will stop the flow of seawater, which will adversely affect the undersea ecosystem. In fact, the structural analysis of the soft-seed bottom equation has not been established yet. Seawater cannot be exchanged because the box or cylinder is sunk, and there is still an ecological problem.

Therefore, the object of the present invention is not required to be a detailed design standard, the foundation part and the ground part (slab) of the artificial island can be easily constructed, and the workability and safety are excellent, and the artificial island is also provided. The purpose of the present invention is to provide a method for constructing an artificial island that is gentle to the global environment because the flow of seawater immediately below and around the river is smooth and does not adversely affect the undersea ecosystem.

[0009]

As a means for solving the above-mentioned problems of the prior art, the method for constructing an artificial island according to the invention of claim 1 comprises: a) a horizontal base part 1 and a base part 1 A vertical wall 2 having a predetermined height rising vertically at the center is formed in an inverted T shape when viewed from the side, and has a hollow air chamber 3 inside the frame of the base 1 and the vertical wall 2 and an air vent plug. 4 to produce the inverted T-shaped unit A on land, b) to horizontally level the seabed 6 at the construction point of the artificial island, and c) to construct the inverted T-shaped unit A on the artificial island. Tow to the construction point, open the air vent plug 4 after reaching the construction point, and land the base 1 on the seabed 6, d) Vertical wall after finishing the inverted T-shaped unit A A slab 5 is formed on the sea surface 7 above the section 2 to construct an artificial island. To be characterized, respectively.

The method for constructing an artificial island according to a second aspect of the present invention comprises: a) a horizontal base portion 1 and a vertical wall portion 2 standing vertically at a central position of the base portion 1 and having a predetermined height. Manufacturing an inverted T-shaped unit A on the land, which is formed in an inverted T-shape, has a hollow air chamber 3 inside the frame of the base 1 and the vertical wall 2, and has an air vent plug 4 attached thereto, b) Adjacent inverted T-shaped units A, A are arranged such that the vertical wall portions 2 and 2 are staggered by changing their directions by 90 degrees so that they are orthogonal to each other, and a desired number of inverted T-shaped units A ... Are joined vertically and horizontally. Forming the assembly block S, c) Horizontally leveling the seabed ground 6 at the construction point of the artificial island, d) Towing the assembly block S to the construction point of the artificial island to reach the construction point. After reaching, the air of the inverted T-shaped unit A You can open the plug 4, thereby landing the base portion 1 to the seabed 6, e) the desired number of building block S ... after finishing the sinking of the upper sea surface 7 of the vertical wall 2 of the inverted T-shaped unit A
Forming the floor slab 5 on the top to construct an artificial island, respectively.

A method for constructing an artificial island according to a third aspect of the present invention is the method of constructing an artificial island according to the first or second aspect, wherein the floor slab 5 is provided on the vertical wall portion 2.
Is formed of precast concrete or cast-in-place concrete.

[0012]

Operation: An inverted T-shaped unit A having a base portion 1 forming a base portion and a vertical wall portion 2 and having an air chamber 3 inside the body.
Can be easily manufactured on land using existing technology (Fig. 2). When constructing a large artificial island as shown in FIG. 1, by joining the relationship between the adjacent inverted T-shaped units A and A to each other in an orthogonal arrangement in which the vertical wall portions 2 and 2 alternately change their directions by 90 degrees. , The assembly block S is easily formed (FIG. 3). Since the inverted T-shaped unit A has a hollow structure and a large buoyancy, it can be towed on the sea.

The single inverted T-shaped unit A or the assembly block S which has reached the construction point of the artificial island can easily construct the base portion of the artificial island by only landing the base portion 1 on the seabed 6. ). Since the horizontal base 1 has a wide bottom surface and the ground pressure is dispersed and small, the bearing capacity of the seabed 6 is low and the stability is good. In addition, since the seabed 6 at the sunk location is leveled in advance, there is no terrain and differential settlement is prevented. The upper portion of the vertical wall portion 2 of the inverted T-shaped unit A that has been sunk protrudes above the sea surface 7 (Fig. 4), and on the vertical wall portion 2, a slab made of precast concrete or cast-in-place concrete is used. 5 can be easily formed, and it will be an artificial island land.

In the large-sized artificial island, the adjacent inverted T-shaped units A, A are arranged orthogonally to each other, so that pollution and stagnation are eliminated without obstructing the flow of seawater between the vertical walls 2 and 2. As a result, it can maintain the underwater ecosystem and effectively resist horizontal forces such as earthquakes (Fig. 1).

[0015]

Embodiments of the present invention shown in the drawings will be described below. FIG. 1 shows the whole of a large artificial island (mainly the structure of the foundation part) constructed on the coast or offshore at a water depth of about 20 m in order to effectively utilize the sea space. This artificial island will be used for large-scale offshore facilities, large-scale marine facilities, large-scale leisure land, and residential areas as well as maritime airports. Reference numeral A in the figure is a single inverted T-shaped unit that constitutes the basic part of the artificial island. Reference numeral 5 is a floor slab that constitutes the land portion. Code 6
Indicates the seabed, and reference numeral 7 indicates the sea surface. This artificial island is constructed by the following method.

First, a plurality of inverted T-shaped units A shown in FIG. 2 are manufactured on land. The inverted T-shaped unit A is composed of a horizontal base portion 1 and a vertical vertical wall portion 2 which is slightly tapered upward and is made of precast concrete. The size of the base 1 is about 20 m in length and width,
It is formed into a large square with a thickness of about 2 m, and a vertical wall 2 with a width of about 20 m, a height of about 20 m, and a thickness of about 2 m stands upright at the center of this base part 1, as seen from the side. It is formed in an inverted T shape. An air chamber 3 for reducing the weight is provided as a hollow structure inside the frame of the base portion 1 and the vertical wall portion 2, and an air vent plug 4 for adjusting the hollow state in the air chamber 3 is provided in the base portion. A plurality of them are attached to the upper surface of 1 and the side surface of the vertical wall portion 2. Although not shown, it is also possible to increase the resistance of the bottom surface of the base 1 to the horizontal force by forming a concavo-convex shaky. In that case, the submerged state on the seabed 6, which will be described later, becomes strong. Further, the inverted T-shaped unit A can be manufactured not only of precast concrete but also of steel, and in this case, it is preferable that the surface of the steel material is subjected to rust prevention treatment.

In the inverted T-shaped unit A, a plurality of building blocks S (see FIG. 3), which are arranged vertically and horizontally and are joined, are formed in a land-based manufacturing yard such as a dock of a large shipyard. However, when the inverted T-shaped unit A is used alone, it is of course unnecessary to form the assembly block S. The size of the assembly block S is such that the entire artificial island is divided into several pieces in the longitudinal direction. In the case of this embodiment, the artificial island is divided into two as shown in FIG.
The letter-shaped units A are formed by closely aligning and joining 5 units in the horizontal direction and 15 units in the vertical direction. At that time, the adjacent reverse T
Vertical wall portions 2, 2 in relation to each other in the shape units A, A
Should be orthogonally arranged with their directions changed by 90 degrees. The adjacent base parts 1 and 1 are connected to each other by tightening the reinforcing bars or the anchor wires 9 (see FIG. 4). Base 1,
The ones may be joined to each other with some distance therebetween.

Before and after the formation of the assembly block S,
The seabed 6 at the construction point of the artificial island is leveled horizontally. The method of leveling the ground is to drop gravel from the sea and spread the gravel on the seabed 6 with the help of a diver or an underwater bulldozer. When the seabed 6 is weak, for example, DCM
By the construction method (registered trademark), ground improvement is performed by adding cement slurry to the soft seabed 6 while mixing and stirring to solidify and stabilize.

Subsequently, the building blocks S are towed one by one to the construction point of the artificial island. The inverted T-shaped unit A forming the assembly block S has a hollow structure with the air chamber 3 and has a small weight to generate buoyancy, and is towed with a small force. After the building block S arrives at the construction point, the air bleeder 4 of each inverted T-shaped unit A is opened and submerged while guiding it with a crane ship, and the building block S is laid so that the base 1 lands on the seabed 6.
To lay down. Next, the second building block S is towed and set in the same manner as described above. When the second building block S is to be sunk, the outer end of the vertical wall 2 of the already sunk building block S is used as a guide (see the portion P indicated by a circle in FIG. 3A). It can be exactly set in a fixed position right next to the first assembly block S.

After the assembly block S is sunk, that is, the construction of the artificial island foundation is completed, as shown in FIG. 4, the upper surface of the vertical wall portion 2 of the inverted T-shaped unit A protruding above the sea surface 7. A floor slab 5, which is an artificial ground, is formed on. Floor slab 5
It is made of precast concrete with a thickness of about 50 cm and is hung by a crane ship. The end of the floor slab 5 is shown in FIG.
As shown in FIG. 5, the pre-stress is introduced to the floor steel plate 5 placed on each half of the upper surface of the vertical wall portion 2 and the PC steel wire 8 arranged in the vertical wall portion 2, and The fixing member 10 firmly binds. When the floor slab 5 is formed in an appropriate area, the mobile crane can be placed and run on the floor slab 5, and the remaining floor slabs 5 can be efficiently installed one after another. Although not shown, it is also preferable to form a floor slab 5 by using a half precast concrete slab having an omnier streak on the upper surface and pouring in-situ concrete. When using the artificial island as a maritime airport, the floor slab 5 is formed over several square kilometers,
There is a risk that sunlight will not reach the sea surface 7 over a wide area. When it is desired to reduce the dark water surface directly under the artificial island, it is possible to easily deal with it by not providing a part of the floor slab 5.

Although the artificial island is completed in this manner, seawater does not flow between the vertical walls 2 and 2 on the lower surface of the artificial island, so that no pollution or stagnation occurs. Therefore, fish can freely pass or live between the vertical walls 2 and 2, so that the marine ecosystem is well preserved. Moreover, since the vertical wall portions 2 and 2 are arranged orthogonally to each other, they effectively resist the seismic force.

[0022]

According to the method of constructing an artificial island according to the present invention, the inverted T-shaped unit A or the assembly block S is manufactured on land, and the work on the sea is performed by towing the inverted T-shaped unit A. Most of them are submerged, which greatly contributes to improvement of workability and safety and shortening of construction period. Further, the inverted T-shaped unit A submerged in the seabed 6 is stable and contributes to the construction of a high quality artificial island. Adjacent vertical wall portions 2 and 2 are arranged orthogonally to each other and good treatment of horizontal force such as an earthquake also contributes to quality improvement, and the permanent stability of the artificial island is maintained. Furthermore, the flow of seawater around the artificial island is smooth, and fish can freely pass or live between the vertical walls 2 and 2 under the artificial island to form a fishing reef, which preserves the marine ecosystem. , An artificial island that is kind to the global environment will be built.

[Brief description of drawings]

FIG. 1 is an overall view showing a completed artificial island.

FIG. 2 is a perspective view showing an inverted T-shaped unit.

FIG. 3A is a plan view showing the structure of an assembly block;
B and C are side views of A.

FIG. 4 is a cross-sectional view showing how to connect the vertical wall portion and the floor slab.

FIG. 5 is a perspective view showing a conventional example.

[Explanation of Codes] A inverted T-shaped unit S assembly block 1 base part 2 vertical wall part 3 air chamber 4 air vent plug 5 floor slab 6 seabed 7 sea level

Claims (3)

[Claims] 1. A) a horizontal base portion and a vertical wall portion of a predetermined height rising vertically at a central position of the base portion are formed in an inverted T shape when viewed from the side, and the base portion and the vertical wall body are formed. Producing an inverted T-shaped unit with a hollow air chamber inside and an air vent plug installed on land, b) Leveling the seabed ground horizontally at the construction point of the artificial island, c ) Towing the inverted T-shaped unit over the sea to the construction point of the artificial island, opening the air vent plug after reaching the construction point, and landing the base on the seabed ground, d) Completing the deposition of the inverted T-shaped unit And then constructing an artificial island by forming a floor slab on the sea surface above the vertical wall portion, respectively. 2. A) A horizontal base portion and a vertical wall portion of a predetermined height rising vertically at a central position of the base portion are formed in an inverted T shape when viewed from the side, and the base portion and the vertical wall body are formed. Produce a plurality of inverted T-shaped units with a hollow air chamber inside and air vent plugs installed on the ground. B) Vertical walls alternate with each other in relation to adjacent inverted T-shaped units. Forming an assembly block by arranging a desired number of inverted T-shaped units side by side in a vertical arrangement by changing the direction by 90 degrees, and c) horizontally leveling the seabed ground at the construction point of the artificial island, d) Towing each of the building blocks on the sea to the construction point of the artificial island, and after reaching the construction point, open the air vent plug of the inverted T-shaped unit and land the base on the seabed, e) Desired number Assembling block After completing the sinking of,
A method for constructing an artificial island, characterized by forming a slab on the sea surface above the vertical wall of each inverted T-shaped unit to construct an artificial island. 3. The method for constructing an artificial island according to claim 1, wherein the floor slab on the vertical wall portion is formed of precast concrete or cast-in-place concrete.