JPH09111734A - Marine structure unit and marine structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a marine structure unit which is easy and economical to construct for wave absorption and a marine structure. SOLUTION: A marine structure unit 1 is constituted by filling a large number of substantially sphere-like bodies 3 in a cage 2, which is easy to adjust an internal void volume. Preferably, the shape of the substantially sphere-shaped bodies 3 are completely spheric or ovally spheric for wave absorption. Preferably, at least the outermost layer of the substantially spheric bodies be formed with a polyolefin-based resin foam so as to enhance shock absorbing properties and durability. The units 1 can be set up in a marine area as a floating body. Preferably, the units 1 be floated by the buoyancy of the substantially sphere- shaped bodies. To adjust the buoyancy of the units 1, the substantially sphere- shaped bodies be integrally compounded with a polyolefin-based resin foam and a weight or the weight is mixed with the substantially sphere-shaped bodies and filled up in the cage 2, which makes it possible to lay out a heavy board- like body on the cage 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an offshore structure unit and an offshore structure, which are mainly installed on the coast of a relatively shallow water near the sea for the purpose of wave breaking.

[0002]

2. Description of the Related Art Conventionally, as an offshore structure that shields the propagation of waves for the purpose of preventing coastal erosion and effectively utilizing the ocean space such as a harbor, a breakwater that breaks and reflects waves and a wave-dissipating block such as a tetrapot are mainly used. However, in recent years, various wave-dissipating structures such as perforated caisson (permeable wall) and floating breakwater have been developed and are being installed in various places with the diversification of the purpose of use of the ocean such as artificial islands. .

[0003]

However, the conventional wave-dissipating structure is an extremely large-scale fixed structure constructed by using a large amount of concrete material, rubble stone, steel material, etc.
The construction required a long time, such as the use of a crane of several thousand tons, and was large-scale and expensive. Further, it has been difficult to adjust the wave-dissipating effect according to the purpose of the conventional wave-dissipating structure because of its material and shape restrictions.

As a solution to such a technical problem, a large number of glass ball floats 20 are provided as shown in FIG. 9 or FIG. 10 with the hint of a culture raft using glass ball floats.
A wave-dissipating structure, which was moored from the seabed BS and arranged in a plane grid pattern in the sea area, was studied, and wave-dissipating control was realized to some extent. However, in such a structure, workability is poor because a large number of floats 20 made of glass balls are individually moored adjacent to each other from the seabed. Moreover, since floats made of glass balls are used, other floats When it comes into contact with a floating object, it breaks without being deformed, and its strength is inferior, and the fact is that it has not been put to practical use.

It is an object of the present invention to provide an offshore structure unit for wave breakage which is easy to construct and economical. Another object of the present invention is to provide an offshore structure which has a sufficient strength and can be easily constructed and whose wave force can be easily controlled.

[0006]

In the marine structure unit of the present invention, a cage in which seawater can freely move in and out is mainly composed of a substantially spherical body having at least the outermost portion formed of a polyolefin resin foam. The filling structure is basically adopted. Further, in the marine structure of the present invention, a fixed type structure for directly fixing the marine structure unit to the seabed and a floating structure for mooring the unit to the seabed are adopted.

It is excellent in cushioning property that the above-mentioned substantially spherical body is composed mainly of a substantially spherical body having at least the outermost portion formed of a polyolefin resin foam, and the shape of the substantially spherical body is excellent in wave-dissipation characteristics. It is preferably spherical or ellipsoidal. When the marine structure unit is installed in a floating type or a fixed type, it is preferable that the substantially spherical body is formed of a polyolefin resin foam having a specific density. Other features and advantages of the present invention will be apparent from the description of the preferred embodiment which follows.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an offshore structure unit according to the first embodiment. The marine structure unit 1 is configured by filling a cage 2 with a plurality of substantially spherical bodies 3, for example, true spherical bodies. The marine structure unit 1 is mainly installed in the ocean for the purpose of wave breaking, but it may be installed in the ocean for the purpose of purifying seawater.

As shown in FIG. 1, the cage 2 has a substantially rectangular surface formed by a frame body 4 forming each side of a hexahedron and has a mesh structure of synthetic resin net, grating, punching metal, welded wire net or fishing net. (FIG. 1 does not show the mesh structure member). There are no particular restrictions on the overall shape of the cage 2 and the mesh structure member as long as seawater can freely enter and leave the cage 2 and a filler such as a substantially spherical body does not flow out. As a material of the cage 2, especially the frame body 4, a steel material, an aluminum material, a concrete material, wood, or a synthetic resin such as FRP can be used.

The marine structure unit 1 of the present invention allows seawater propagating waves to pass through the cage 2, and when the seawater passes through the internal void formed between the substantially spherical bodies 3, the substantially spherical body 3 causes the waves to wave. It absorbs and attenuates force. The substantially spherical body 3 is
A substantially spherical shape such as a perfect sphere or an elliptical sphere is preferable because of its high wave-dissipating ability. The buoyancy has the property of expanding in an elliptical shape at a position where the water depth is deeper, and accordingly, it is particularly preferable to fill the ellipsoidal substantially spherical body 3 because the effect of weakening the wave force becomes high.

In the present invention, the marine structure unit 1
The gap between the plurality of substantially spherical bodies 3 filled in the cage 2 is called an internal void, and the percentage of the ratio of the volume of the internal voids to the apparent volume of the plurality of substantially spherical bodies 3 filled in the cage 2 is a percentage. Is called the internal porosity. By changing the size and shape of the substantially spherical body 3, a plurality of types of substantially spherical bodies 3 having different sizes and shapes are further mixed and filled in the cage 2 so that the internal void ratio between the substantially spherical bodies in the cage 2 is increased. By adjusting, the wave force can be weakened and the effect can be adjusted. For example, by filling the cage 2 with a substantially spherical body having a single diameter, the internal porosity between the substantially spherical bodies in the cage 2 is 45% to 25%.
Can be adjusted to a wave-eliminating effect. Further, by mixing and filling the substantially spherical bodies having greatly different diameters into the cage 2, the internal porosity between the substantially spherical bodies in the cage 2 can be adjusted to 25% to 15%. Since it has a smaller size, a high wave-dissipating effect can be obtained, and it is effective when used in aquatic areas such as aquaculture where particularly quieting is required. The substantially spherical body 3 used in the present invention preferably has a maximum diameter of 100 mm to 900 mm. In the offshore structure unit 1 installed in the ocean, it is difficult to directly measure the internal porosity between the plurality of substantially spherical bodies 3 filled in the cage 2, but in water, the substantially spherical body 3 is affected by hydraulic pressure. Three
Since they are dimensionally compressed substantially uniformly, the volume of the internal voids between the substantially spherical bodies 3 changes substantially in proportion to the change in the volume of the substantially spherical bodies 3, and the substantially spherical body 3 is compressed by hydraulic pressure. The change in the internal porosity between the spherical bodies 3 is minute. Therefore, the internal porosity between the substantially spherical bodies 3 of the marine structure unit 1 on the ground can be adopted as the internal porosity between the substantially spherical bodies 3 of the marine structure installed in the ocean. Although the volume of the substantially spherical body decreases due to the water pressure, there is a gap in the marine structure unit, but when the density of the substantially spherical body is smaller than that of seawater, the substantially spherical body gathers above the marine structure unit. Therefore, there is no gap due to the volume reduction of the approximately spherical body at the wave-dissipating portion, and the wave-dissipating ability is not affected. In addition, when the density of the substantially spherical body is higher than that of seawater, the volume change of the substantially spherical body due to water pressure is small, and there is almost no clearance, so that the wave-dissipating ability is less affected. Therefore, the measurement of the internal porosity in the present invention is performed on the ground. The smaller the internal porosity measuring cage is, the easier it is to handle.However, it is necessary that the cage is sufficiently larger than the maximum diameter of the substantially spherical body filled inside to reduce the measurement error. In the present invention, a cubic internal cage for measuring the internal porosity having a length of 3 m, a width of 3 m, and a height of 2 m is used in the invention, and has substantially the same configuration as a substantially spherical body which is actually filled in the marine structure unit. The spheres are filled to fill the measuring cage. When filling the cage of the actually constructed marine structure unit with a substantially spherical body, when pushing the substantially spherical body into the cage with a constant force or alternately filling two types of substantially spherical bodies of different diameters by a fixed amount In the case of doing so, the same method is used when filling the measurement cage with the substantially spherical body. When filled to fill the substantially spherical body in the internal porosity measurement cage, the volume in the measurement cage can be regarded as the apparent volume of the filled substantially spherical body, and thus the substantially spherical body filled in the measurement cage. The internal porosity is calculated from the true volume of the body by the following formula. The true volume of the substantially spherical body filled in the measuring cage is measured by immersing the measuring cage filled with the substantially spherical body in water. As described above, by appropriately selecting the size and shape of the substantially spherical body 3 and adjusting the configuration inside the cage 2, it is possible to perform the wave suppression control according to the purpose.

In the present invention, since at least the outermost layer is mainly composed of the substantially spherical body 3 made of a polyolefin resin foam having excellent buffering properties, it comes into contact with other substantially spherical bodies or the frame of the cage. Is less likely to be damaged,
Compared to polystyrene-based resin foams, they have superior durability such as toughness and compressive residual strain, and are less likely to be deformed by repeated collisions with other substantially spherical bodies or cage frames due to wave forces.

When the marine structure unit 1 is installed in the ocean in a floating manner, it is preferable to levitate the unit by the buoyancy of the substantially spherical body 3 filled in the cage 2 because it is not necessary to attach any other levitation means. From this point as well, a substantially spherical body using a polyolefin resin foam is mainly used.

Polyolefin resin foams applicable to this are laminated, for example, by laminating plate-like foams obtained by an extrusion foaming method and molding them by secondary processing, or filling foaming beads into a molding die. It can be easily obtained by heating and integrally molding.

As the polyolefin resin, low density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, propylene-ethylene random copolymer, propylene-ethylene block copolymer,
There are propylene-butene random copolymers, propylene-butene block copolymers, ethylene-propylene-1-butene random copolymers and the like, and crosslinked or non-crosslinked ones are used. Of these, polypropylene resins are particularly preferable, and Japanese Patent Application No. 6-76498.
No. 1-butene or a specific propylene-based random copolymer containing a monomer component of 1-butene and ethylene as a base resin, a synthetic resin foam has a compression set, rigidity such as compression strength. It is particularly preferable because it is excellent.
Further, the substantially spherical body 3 may be covered with a flexible material such as rubber or rubberized cloth to improve impact resistance or abrasion resistance.

The substantially spherical body 3 to be filled in the cage 2 is preferably in the shape of a true sphere or an ellipsoid because of its high wave-dissipating ability. The wave force has a property of spreading in an elliptical shape as the water depth increases, and accordingly, it is particularly preferable to make the substantially spherical body 3 into an ellipsoidal shape because the effect of weakening the wave force is enhanced. By changing the size of the substantially spherical body 3 or by filling the cage 2 with several kinds of substantially spherical bodies 3 having different sizes and / or shapes, the internal porosity between the substantially spherical bodies in the cage 2 can be adjusted. May be.

The buoyancy of the offshore structure unit 1 needs to be adjusted appropriately, especially in the floating type. If the buoyancy is too large, it is necessary to make the concrete anchor for fixing the unit 1 large in size, and the work at the time of construction associated with this becomes large. On the other hand, if the buoyancy is too small, the floating unit in particular becomes unstable or sinks, and the proper top position cannot be maintained.

The density of seawater is generally 1.02 g / cm
It is in the range of ^{3 to} 1.03 g / cm ³ . Therefore, when the substantially spherical body 3 is formed using a synthetic resin having a density lower than that of seawater, such as polyethylene or polypropylene,
Even if it is non-foamed, it causes buoyancy. However,
When only the non-foamed one is used, the buoyancy obtained by the substantially spherical body 3 is small, and it is difficult to adjust the buoyancy. Therefore, it is not possible to configure the floating marine structure unit 1 with only the non-foamed synthetic resin. It's not easy.

Even in the case where the non-foamed synthetic resin is a hollow body, if the hollow body is damaged, there is a possibility that the unit 1 may become unstable or sink due to water infiltration, which significantly reduces buoyancy. It is not preferable to use it as the main body of a spherical body.

The buoyancy of the marine structure unit 1 is adjusted by adjusting the density and layer thickness of the polyolefin resin foam used in at least the outermost layer of the substantially spherical body 3. Further, a plurality of types of substantially spherical bodies 3 having different densities are mixed at an appropriate ratio, and further, a substantially spherical body made of a polyolefin resin foam and a lump made of a non-foaming synthetic resin are mixed at an appropriate ratio. It can also be adjusted by

The polyolefin resin foam used for the substantially spherical body 3 has a density of 0.06 g / cm ³ to 0.9.
Those of 0 g / cm ³ are particularly preferable. The density of the polyolefin resin foam referred to here is the density of the polyolefin resin foam portion forming at least the outermost layer in each substantially spherical body, and a portion of the polyolefin resin foam is cut out and the weight ( After measuring g), the cut out foam is completely submerged in the alcohol in the graduated cylinder containing alcohol, and the volume (cm ³ ) is measured by reading the increment on the scale of the graduated cylinder to measure the weight. It is a value obtained by dividing by. If the density exceeds 0.90 g / cm ³ , the buoyancy and cushioning properties are insufficient, while if the density is less than 0.06 g / cm ³ , it must withstand the water pressure applied when it is submerged in the seabed. However, it is difficult to adjust the buoyancy due to a large volume change, and there is a possibility that the target internal porosity cannot be secured. The layer thickness of the polyolefin resin foam of the substantially spherical body 3 is preferably 5 cm or more, more preferably 15 cm or more from the viewpoint of buoyancy and cushioning property.

By adjusting the density of the polyolefin resin foam forming the substantially spherical body 3, the buoyancy of the substantially spherical body 3 filled in the cage 2 can be adjusted, and the size and size of the substantially spherical body 3 can be adjusted. It is easy to keep the buoyancy of the marine structure unit 1 in an appropriate range when adjusting the shape to adjust the internal porosity between the substantially spherical bodies in the cage 2.

The density of the substantially spherical body 3 adjusts the density of the polyolefin resin foam, and also makes the substantially spherical body 3 a composite integrated body with foams having different densities. It can also be adjusted by forming a composite integrated product with a foamed synthetic resin, stone material, concrete material and the like. In this case, at least the outermost layer of the substantially spherical body 3 is made of a polyolefin resin foam so that the buffering property of the substantially spherical body 3 is not impaired. The composite integrated product is
For example, a spherical body made of high-density material such as concrete material, stone material, and steel material is integrated with two hollow hemispherical polyolefin resin foams having the same inner diameter by sandwiching, adhering, or heat-sealing. Alternatively, a polyolefin-based resin foam may be used to form a substantially spherical body having recesses, and the recesses may be filled with a high-density substance. Such a polyolefin-based resin foam molded article can be easily obtained by filling the molding die with the polyolefin-based resin foam beads and performing heat integral molding.

The adjustment of the buoyancy by the main spherical body is as described above, but in addition, by filling the cage 2 with a heavy material such as a stone material or a concrete material together with the main spherical body 3 described above. It is possible.

In the offshore structure of the present invention, when the offshore structure unit 1 is a floating offshore structure moored on the seabed, the density of the substantially spherical body 3 is 0.06 g / cm ³ to 0.
90 g / cm ³ is preferable because it gives a buoyancy suitable for levitating the marine structure unit 1. The density of the substantially spherical body mentioned here is the density of each substantially spherical body, and is a value obtained by dividing the weight (g) of each substantially spherical body by its volume (cm ³ ). The volume of each substantially spherical body is determined by completely submerging the substantially spherical body in a water tank containing water and measuring the increment of the scale on the balance line of the water tank.

When the offshore structure unit 1 is a fixed type offshore structure which is directly fixed to the seabed, buoyancy to float the unit 1 is not necessary, and when the buoyancy is excessively large, the offshore structure is stable. Since it becomes difficult to fix objects directly to the seabed, the density of the substantially spherical body 3 is 0.06 g / cm.
³ to preferably set to 1.80 g / cm ^3, density weight of substantially spherical body 3 becomes large exceeding 1.80 g / cm ^3, workability may be decreased.

Since the density of the substantially spherical body 3 can be adjusted in a wide range by using the polyolefin resin foam, the buoyancy according to the internal porosity between the substantially spherical bodies in the cage 2 for controlling the wave-dissipation. Not only is it easier to adjust
The force required for mooring or directly fixing the offshore structure to the seabed can be reduced, and the workability of the structure is greatly improved.

FIG. 2 shows a second embodiment of an offshore structure suitable for floating mooring. In the second embodiment, the intermediate layer 8 is constituted by the unit 1 which is mainly filled with spherical bodies made of polypropylene resin foam in a cage (not shown). The upper layer 7 of the unit 1 has a concrete plate-like body. Is laid and a concrete plate-like body is attached to the lower layer 9 to form an offshore structure. The unit 1 has, for example, a length of 10 m, a width of 10 m, and a height of 5 m, the upper layer 7 has a height dimension of 300 mm, and the lower layer 9 has a height dimension of 150 m.
m.

The intermediate layer 8 comprises a plurality of substantially spherical bodies 1 in a cage.
This spherical body 11 is composed of a unit 1 filled with 1
Contains two types of substantially spherical bodies, one of which is a polypropylene foam (diameter 300 mm) and the other of which is a recovered melt (recovered polystyrene molten solid). The shape of the substantially spherical body made of this recovered melt is indefinite. The lower layer 9 and the upper layer 7 also serve as weights for adjusting the buoyancy by being composed of a plate-shaped body made of a heavy material such as a concrete plate-shaped body or a steel plate. In addition, in the upper layer 7 and the lower layer 9, the plate-shaped body 10 may be laminated not only in one layer but in two or more layers. Each of these layers 7, 8, 9
The characteristics of the members included in Table 1 are shown in Table 1 below.

[0030]

[Table 1]

In the case of the floating type ocean installation, the above-mentioned first
In addition to using the unit of the embodiment and the unit 1 of the second embodiment, it is also possible to construct a marine structure by mooring a large number of substantially spherical bodies 3 or 11 simply surrounded by a fishnet on the seabed BS.

3 to 7 show an example of installation of the above-mentioned offshore structure unit 1 in the sea. 3 and 4 use concrete piles, steel pipe piles, etc. placed on the sea floor to
4 shows an example of a fixed marine structure in which the cage 2 is directly fixed to the seabed BS. Of these, FIG. 3 shows an example in which the upper part of the marine structure unit 1 is exposed from the water surface S and installed, and FIG. Shows an example in which the marine structure unit 1 is installed so as to be entirely submerged below the water surface S.

As described above, the offshore structure unit 1 is
Seawater that propagates waves is passed through a gap formed between adjacent substantially spherical bodies 3, 3 to absorb and attenuate the wave force. Therefore, as in the installation example of FIG. 3, the upper portion of the unit 1 may be exposed and installed from the water surface S, but as shown in FIG. 4, the unit 1 should be entirely submerged below the water surface S. You may install it. In this case, the top end 1 of the marine structure 1
The water depth of a may be set by selecting a depth suitable for absorbing waves. According to the installation method of FIG. 4, since the unit 1 is not exposed above the water surface S, it is possible to provide a submerged dike type marine structure that has little influence on the landscape.

FIGS. 5 to 7 show an offshore structure unit 1.
The figure shows an example of a floating offshore structure moored to the seabed. Thus, when the unit 1 is installed in the floating type, the concrete anchor 13 installed on the seabed BS and the unit 1 may be connected by the chain 14. At this time, it is preferable that the length dimension of the chain 14 and the buoyancy of the unit 1 are adjusted to fixedly moor the unit 1 in the sea by a tension leg system in which the chain 14 is in a tensioned state.

FIG. 5 shows an installation example in which the upper part of the unit 1 is exposed from the water surface S. In the case of the floating installation of FIG. 5, the height dimension of the exposed portion of the unit 1 located above the water surface and the water surface S are adjusted by adjusting the length dimension of the mooring chain 14 and the buoyancy of the unit 1. It is possible to arbitrarily adjust the height dimension of the undersea portion of the unit 1 located below from. FIG. 6 shows an installation example in which the unit 1 is wholly submerged below the water surface S. As a method for mooring the unit 1 on the seabed, a catenary mooring method, a tension leg mooring method, and the like are known, but the tension leg mooring is preferable because it suppresses horizontal motion.

FIG. 7 shows an installation example in which the upper part of the unit 1 is exposed from the water surface S and a plurality of chains 14 for mooring the unit 1 are converged into one on the way and connected to one concrete anchor 13. . According to the floating type installation shown in FIG. 5 to FIG. 7, it is sufficient to install the concrete anchor 13 on the seabed BS, so that there is an advantage that a large-scale foundation structure is unnecessary, and further, the buoyancy is adjusted. With this, the unit 1 can be installed in a floating type by inserting the unit 1, the throw-in anchor and the mooring chain 14 into the water, and the unit 1 can be installed in the concrete anchor installed on the seabed by the underwater work. Installation of the unit 1 is extremely easy because no connection work is required.

If the marine structure unit 1 is assembled on land regardless of whether it is a fixed type or a floating type, the work on the sea can be reduced. On the other hand, after arriving at the destination, the frame body 4 in the ocean
Is installed, each surface of the frame body 4 is surrounded by a mesh member to form the cage 2, and then the substantially spherical bodies 3, 11 are formed in the frame body 4.
If the unit is filled with, the buoyancy and internal porosity of the unit 1 can be adjusted while adjusting the size, density, shape, etc. of the substantially spherical body to be filled, and the adjustment is also easy. Is.

An offshore structure is constructed by installing the offshore structure unit 1 in the ocean. Although the offshore structure unit 1 exhibits the wave-dissipating ability even when used alone, it is possible to control the wave-dissipation over a wide range by installing a plurality of units in the ocean. It may be an offshore structure having various forms and functions such as a bank.

When installing a plurality of offshore structures, a plurality of units may be arranged by connecting the units to each other as shown in FIG. 8 (b), or as shown in FIG. 8 (c). Can be arranged adjacent to each other, or the units can be staggered in a staggered manner as shown in FIG. 8 (d). Is preferable because it can be eliminated. 8 (b) to 8 (d), the arrangement shown in FIG. 8 (d) has the highest wave-dissipating ability, and is preferably used in a sea area requiring a high degree of tranquilization.

FIG. 8A is a diagram showing an offshore structure constructed by installing a plurality of offshore structure units of the present invention in the form of a headland bank. It has the advantage of being able to prevent coastal erosion, which is a feature of the Headland bank, and artificially forming a sandy beach in the sea area calmed by the bank.

Further, since this marine structure has many voids between the substantially spherical bodies 3, 3 or 11, 11 filled inside, it also functions as a fishing reef. Further, since seaweed adheres to the surfaces of the substantially spherical bodies 3 and 11 to have a function of purifying seawater, the whole structure surrounds the sea area as a wave-dissipating structure or a planar wave-dissipating structure. Not only can the seawater be rendered quiet by using it, but it can also be purified.

In the case where the upper surface of the unit 1 is exposed above the sea surface or located near the sea surface, the upper part of the unit is formed of a plate-like body like the offshore structure of the second embodiment. The top of the offshore structure can be made flat. According to this, the upper surface of the cage can be used as a work space, and can also be used as a stage or the like in the recreation area.

Particularly, when the unit 1 is installed in a floating type, it is not necessary to construct a large-scale foundation structure, so the ground is soft, and a conventional marine structure can support a heavy foundation structure. Even if it subsides, or if the submarine ground has a steep slope and it is difficult to install the foundation structure or the foundation structure becomes extremely large, it is easy to remove the offshore structure. Can be installed.

[0044]

As described above, in the marine structure unit of the present invention, a plurality of substantially spherical bodies in which at least the outermost layer is formed of the polyolefin resin foam are provided inside the cage in which seawater can freely flow in and out. It is preferable that the substantially spherical body has a spherical shape or an elliptic spherical shape because of its high wave-dissipating ability.
Adjust the internal porosity between the approximately spherical bodies in the cage by appropriately selecting the internal configuration of the cage, such as changing the size and shape of the approximately spherical bodies filled in the cage, or mixing multiple types of approximately spherical bodies. The wave-dissipating ability can be adjusted according to the purpose. Specifically, by filling the cage with a substantially spherical body having a single diameter, the internal porosity between the substantially spherical bodies in the cage can be adjusted to 45% to 25%, and a wave-dissipating effect can be obtained. Furthermore, by mixing substantially spherical bodies having greatly different diameters and filling the cage, the internal porosity between the substantially spherical bodies in the cage can be adjusted to 25% to 15%. In this case, the internal porosity is smaller. Since it has a high wave-dissipating effect, it is particularly effective when used in aquatic areas such as aquaculture areas where tranquilization is required. Further, in the marine structure unit of the present invention, the main body of the substantially spherical body filled inside the cage is a substantially spherical body in which at least the outermost layer is made of a polyolefin resin foam, and the buoyancy thereof causes the marine structure. The unit can be moored and fixed in a floating manner. Further, since the substantially spherical body is lightweight, workability is good, and since at least the outermost layer is formed of a polyolefin resin foam, it is excellent in cushioning property, durability, and is not easily damaged. The base resin of the polyolefin-based resin foam that forms the substantially spherical body,
Polypropylene resin, particularly ethylene-propylene random copolymer, propylene-butene-1 random copolymer, ethylene-propylene-1-butene random copolymer and the like are preferable, and especially 1-butene or 1-butene and ethylene monomer. It is preferable to use a specific propylene-based random copolymer containing components because it is excellent in compression set and compression strength. Furthermore, the foam density is 0.06 g / cm ³
Or 0.90 g / cm ³ , the volume change due to water pressure is small, and it is easy to adjust the buoyancy and the internal porosity between the approximately spherical bodies in the cage, and effectively eliminate the waves. You can In addition to adjusting the density of the polyolefin-based resin foam, the outer layer is mainly composed of a polyolefin-based resin foam with a substantially spherical body having a double structure, and a synthetic resin foam having a different density from the outer layer inside, a non-foaming synthetic resin,
The buoyancy can also be adjusted by adjusting the density of the substantially spherical body by combining and integrating high-density materials, etc. In this case, since the outermost layer of the substantially spherical body is composed of a polyolefin resin foam, it has a cushioning property. Will not hurt. Further, in the present invention, a plate-shaped body may be laid on the upper part of the marine structure unit and the top end may be formed as a flat surface, and when the flat surface is located on or near the sea surface, the work space is It can be used for stage, etc. A plate-like body to a concrete plate-like body,
Alternatively, it can be used as a weight for adjusting the buoyancy of the offshore structure unit by constructing it with a heavy object such as a steel plate. Further, the marine structure of the present invention is a floating type marine structure formed by mooring the marine structure unit from the seabed, or a fixed type formed by fixing the marine structure unit to the seabed. When using a plurality of offshore structure units, which are offshore structures, it is possible to control the wave-dissipating ability according to the purpose by adjusting the planar arrangement of the offshore structure units. Further, in the offshore structure of the present invention, the offshore structure unit can be a submerged dike type offshore structure installed below the surface of the water, and by adjusting the top water depth to an appropriate depth It is possible to reduce wave influence and effectively absorb and attenuate wave force. Compared with conventional offshore structures constructed using a large amount of concrete materials, rubble stones, steel materials, etc., construction is easier, and the period required for construction can be greatly shortened. The large-scale foundation structure is not necessary when installing in, and it is possible to install the offshore structure on the soft ground or the seabed ground with a steep slope.

[Brief description of the drawings]

FIG. 1 is a schematic front view of a marine structure unit according to a first embodiment.

FIG. 2 is a partially omitted perspective view of a marine structure according to a second embodiment.

FIG. 3 is an explanatory diagram of marine installation showing an example in which the upper part of the marine structure unit of the embodiment is projected from the sea surface and directly installed on the seabed ground.

FIG. 4 is an explanatory diagram of marine installation showing an example in which the marine structure unit of the embodiment is entirely sunk from the sea surface and directly installed on the seabed.

FIG. 5 is an explanatory view of offshore installation showing an example in which the upper portion of the offshore structure unit according to the embodiment is projected from the sea surface and installed in a floating manner.

FIG. 6 is an explanatory view of offshore installation showing an example in which the offshore structure unit of the embodiment is entirely immersed from the sea surface and installed in a floating manner.

FIG. 7 is an explanatory view of offshore installation showing another example in which the offshore structure unit of the embodiment is installed in a floating manner with its upper part protruding from the sea surface.

FIG. 8A is an explanatory diagram of offshore installation showing an example of a headland bank formed using the offshore structure unit of the present invention. (B) is an explanatory view of offshore installation showing an example in which a plurality of offshore structure units are connected to each other and arranged.
(C) is an explanatory view of offshore installation showing an example in which a plurality of offshore structure units are arranged adjacent to each other. (D) is an explanatory view of offshore installation showing an example in which a plurality of offshore structure units are alternately arranged in a staggered manner.

FIG. 9 is a view showing various conventional examples in which floating balls are moored to the sea floor.

FIG. 10 is a diagram showing an installation example in which many conventional floating balls are moored to the seabed.

[Explanation of symbols]

 1 Offshore structure unit 2 Cage 3, 11 Approximately spherical body 6 Offshore structure 10 Plate material 13 Concrete anchor 14 Chain BS Submarine ground

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takaaki Eguchi 3-16 Asamacho, Hiratsuka-shi, Kanagawa Churis Hiratsuka 907 (72) Inventor Masahiro Hashiba 24-5 Daikancho, Hiratsuka-shi, Kanagawa Terrace House Tanaka A

Claims (4)

[Claims] 1. A marine structure unit in which a plurality of substantially spherical bodies, at least the outermost layer of which are formed of a polyolefin resin foam, are mainly filled in a cage in which seawater can freely flow in and out. The density of the polyolefin resin foam is 0.06 g / cm ³ to 0.90 g / cm ³ , and the internal porosity between the substantially spherical bodies in the cage is 15% to 45%. Offshore structure unit. 2. A plate-shaped body is laid on the upper surface of the cage,
The marine structure unit according to claim 1, wherein the top end is a flat surface. 3. A floating type formed by mooring the marine structure unit according to claim 1 or 2, wherein the density of the substantially spherical body is 0.06 g / cm ³ to 0.90 g / cm ^3. Offshore structure. 4. An immobilization formed by directly immobilizing the marine structure unit according to claim 1 or 2 wherein the density of the substantially spherical body is 0.06 g / cm ³ to 1.80 g / cm ^3. Offshore structure.