JP2022178448A - Floating body structure supporting structure and installation method of floating body structure - Google Patents

Abstract

To provide a floating body structure supporting structure capable of stably supporting a floating body structure.SOLUTION: A floating body structure supporting structure 1 is mainly composed of a floating body structure 3, floating bodies 5, a base part 7, a lower connection part 9, an oscillation preventing member 11, and the like. The multiple floating bodies 5 are horizontally installed side by side. A vertical length of the floating body 5 is longer than its horizontal width. For example, a horizontal cross section of the floating body 5 is roughly circular, and a vertical cross section perpendicular to the horizontal direction has a shape such as roughly elliptical or roughly oval. The floating body 5 is made of precast concrete in which a space 13 is formed. A ballast water such as seawater can be introduced and discharged into/from the inside of the floating body 5, from an introduction port or a discharge port.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a support structure for supporting a floating structure on the ocean or the like, and a method for installing the floating structure.

As an offshore structure such as an offshore wind turbine, a method of supporting a tower or the like in a floating structure has been proposed. As a support structure for such a floating structure, a steel floating body is generally used. However, steel floats deteriorate with time, such as rust, and require regular inspections and repairs. Inspection and repair work are required.

On the other hand, a method using a concrete floating body has been proposed (for example, Patent Documents 1 to 3).

Japanese Patent Publication No. 2014-503424 JP 2017-129061 A Japanese Patent Publication No. 2018-502761

Normally, when supporting a floating structure using such a concrete floating body, it is necessary to stabilize the floating body and the structure on the floating body. For this reason, for example, as in Patent Documents 1 and 2, a method using a flat floating body in which a dimension (width or diameter) perpendicular to the depth direction (thickness) is increased, or a method in Patent Document 3, As shown in the figure, the general method is to use a floating body element of a predetermined length by laying it down in the horizontal direction.

However, the inventors have found that the forms disclosed in Patent Documents 1 to 3 do not necessarily sufficiently consider the effects of waves and tides, and are easily affected by waves and tides. Therefore, there is a demand for a floating structure support structure that is less susceptible to waves and the like and is capable of stably supporting a structure.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a floating structure support structure and the like capable of stably supporting a floating structure.

In order to achieve the above object, a first invention is a support structure for a floating structure, comprising: a plurality of floating bodies each having a length in the vertical direction longer than a width in the horizontal direction; and a base portion to which a floating structure is fixed, the floating body having a curved outer peripheral surface and being made of precast concrete with a space formed therein, and ballast is introduced into the inside of the floating body. and discharge is possible.

The floating body has an upper curved surface member, a lower curved surface member, and a ring-shaped member sandwiched between the upper curved surface member and the lower curved surface member, the upper curved surface member and the lower curved surface member It may be joined via ring-shaped members, and the size of the floating body may be adjustable according to the number of the ring-shaped members between the upper curved surface member and the lower curved surface member.

The anti-swing member may be made of precast concrete with a hollow interior, and ballast may be introduced into the interior of the anti-swing member.

The anti-swing member may be connected to the base portion or the floating structure by a rod member.

The floating structure may be a wind turbine for offshore wind power generation, and the rod-shaped member may be inserted inside a column of the wind turbine for offshore wind power generation.

According to the first invention, since the floating body is made of precast concrete, there is no problem such as rust unlike steel floating bodies. In addition, unlike steel floating bodies, it does not require special work such as welding at a shipyard, so it can be assembled in coastal areas near the installation site. Therefore, work such as assembly work and transportation of the support structure is easy.

In addition, since the outer surface of the floating body is curved, it is less susceptible to tidal currents and waves. In addition, since a plurality of floating bodies are used and the length in the vertical direction of each floating body is longer than the width in the horizontal direction, a normal shape with the same volume (buoyancy) (for example, a flat shape as in Patent Documents 1 to 3) The cross-sectional area across the water surface can be made smaller compared to a shape with a horizontal longitudinal direction. Therefore, it is possible to further reduce the influence of waves and the like.

For example, a completely spherical floating body and a floating body with a vertically flattened cross-sectional shape such as an ellipse, an oval, or an egg-shaped vertical cross section can cross the water surface if they have the same volume. can reduce the cross-sectional area of Therefore, it is possible to suppress the force that the floating body receives from waves and tides, especially near the surface of the water.

In addition, by forming the floating body by sandwiching a ring-shaped member between the upper curved surface member and the lower curved surface member, substantially the entire surface (side surfaces and upper and lower surfaces) can be configured with curved surfaces, and the number of ring-shaped members The size of the floating body can be adjusted accordingly. Therefore, it is possible to manufacture floating bodies of many sizes by sharing members.

In addition, by arranging the anti-swing member below the base portion and lifting the anti-swing member upward during assembly and towing, it is possible to prevent the anti-swing member from interfering with work and towing. be able to. In addition, by lowering the anti-swing member into the water at the installation location of the floating structure, the center of gravity of the entire support structure for the floating structure can be moved downward. In addition, since the anti-swing member provides resistance in water, it functions as an anti-swing damper and can support the floating structure more stably.

At this time, by making the anti-swing member made of precast concrete, there is no problem such as rusting as with the floating body, and the assembling workability is also good. In addition, by making it possible to introduce ballast into the inside of the anti-swing member, when the floating structure is installed, ballast can be introduced into the inside and buoyancy can be minimized. Therefore, the center of gravity of the entire floating structure support structure can be moved downward and stabilized.

In addition, by connecting the anti-swaying member to the base portion or the floating structure with a rod-shaped member, the upper floating structure can be reduced in comparison with the case of connecting with a flexible member such as a wire or chain, for example. Since a force can be directly transmitted between objects, it is possible to efficiently suppress rocking and vertical movement of the floating structure.

Moreover, when the floating structure is a wind turbine for offshore wind power generation, the rod-shaped member can be inserted and accommodated inside a column of the wind turbine for offshore wind power generation. In addition, by connecting the strut and the rod-shaped member, the function of the anti-swing damper for the offshore wind power generation facility can be exhibited more efficiently.

A second invention is a method for installing a floating structure using the floating structure support structure according to the first invention, wherein the floating structure support structure is moved to an installation location with the anti-swing member raised. and lowering the anti-sway member into the sea at the installation site, and mooring the floating structure support structure to the seabed. is.

According to the second invention, by pulling up the anti-swing member at the time of assembly and towing, it is possible to prevent the anti-sway member from interfering with work and towing, and the floating structure can be installed at the installation site. By lowering the anti-swing member into the sea, the center of gravity of the floating structure support structure can be moved downward and stabilized.

ADVANTAGE OF THE INVENTION According to this invention, the floating structure support structure etc. which can support a floating structure stably can be provided.

The figure which shows the floating structure support structure 1. FIG. (a), (b) is a figure which shows the form of the base part 7. FIG. 4(a) and 4(b) are diagrams showing the arrangement of the floating structure with respect to the base portion 7. FIG. The figure which shows the construction state of the floating structure support structure 1. FIG. (a), (b) is a figure which shows the state which installs the floating structure support structure 1. FIG. (a), (b) is a figure which shows the assembly structure of the floating body 5. FIG. (a), (b) is a figure which shows the assembly structure of the floating body 5. FIG. (a), (b) is a figure which shows the assembly structure of the floating body 5. FIG. 4(a) to 4(d) are diagrams showing the anti-swing member 11. FIG. The figure which shows the other rocking prevention member 11. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail based on the drawings. FIG. 1 is a diagram showing a floating structure support structure 1. FIG. A floating structure support structure 1 is a support structure for supporting a floating structure 3 while floating on water.

In this embodiment, the floating structure 3 is a wind turbine for offshore wind power generation, but the floating structure 3 may have other structures. For example, the present invention can be applied to any structure as long as it is used while floating on water, such as a floating pier.

The floating structure support structure 1 is mainly composed of a floating structure 3, a floating body 5, a base portion 7, a lower connecting portion 9, an anti-swing member 11, and the like. A plurality of floating bodies 5 are arranged side by side in the horizontal direction. For example, in this embodiment, four floating bodies 5 are arranged at substantially equal intervals.

The length of the floating body 5 in the vertical direction is longer than the width in the horizontal direction. For example, the horizontal cross section of the floating body 5 is substantially circular, and the vertical cross section orthogonal to this is substantially elliptical or elliptical, which is vertically flattened. That is, substantially the entire outer peripheral surface of the floating body 5 is configured with a curved surface.

Here, the expression that the outer surface of the floating body 5 is formed with a curved surface means that portions other than the joint portion with the base portion 7 and the lower connecting portion 9, which will be described later, and the ballast introduction port, etc., are formed with curved surfaces. . That is, even if a portion of the outer surface has a flat portion or uneven structure for functional or manufacturing reasons, the outer surface of the floating body 5 can be is included in those composed of curved surfaces.

The floating body 5 is made of precast concrete with a space 13 formed therein. Ballast such as seawater can be introduced into and discharged from the inside of the floating body 5 through an inlet or outlet (not shown). A partition 15 is provided inside the floating body 5 . A partition 15 allows ballast to be introduced to the lower part of the floating body 5 . By introducing the ballast into the lower part of the floating body 5 in this manner, the floating body 5 can be stably floated on the water with its longitudinal direction directed vertically. In addition, the partition 15 can suppress sloshing of the ballast water in the space 13 when the floating body 5 shakes. The partition 15 does not form a completely closed space in the space 13, but may be provided with a plurality of holes for water passage. Even in this way, sloshing can be suppressed by the resistance when water flows. Further, the partition 15 may partition the inside of the floating body 5 in the horizontal direction or the partition in the vertical direction.

A lower connecting part 9 is arranged at the lower part of the plurality of floating bodies 5 , and a base part 7 is arranged at the upper part of the floating bodies 5 . That is, the plurality of floating bodies 5 are connected by the lower connecting part 9 at the lower part and connected by the base part 7 at the upper part. The base portion 7 and the lower connecting portion 9 may be made of steel or may be made of precast concrete. Also, apart from the base portion 7, an upper connecting member for connecting the upper portion of the floating body 5 may be arranged.

An anti-swing member 11 is arranged below the base portion 7 and at the central portion of the plurality of floating bodies 5 . Like the floating body 5 , the anti-swing member 11 is also made of precast concrete with a hollow interior, and ballast can be introduced into the anti-swing member 11 .

The floating structure 3 is fixed on the base portion 7 . The anti-swing member 11 is connected to the base portion 7 or the floating structure 3 by a rod member 17 . For example, as described above, when the floating structure 3 is a windmill for offshore wind power generation, the rod-shaped members 17 are inserted and fixed inside the columns of the windmill for offshore wind power generation. Note that the anti-swing member 11 can be lowered below the base portion 7 . The action of the anti-swing member 11 will be described later.

FIG. 2(a) is a plan view showing the arrangement of the floating body 5 and the like with respect to the base portion 7. FIG. As shown in the figure, when four floating bodies 5 are used, the base portion 7 is made substantially square, and each floating body 5 is arranged near the vertex of the base portion 7 . By doing so, the base portion 7 and the floating structure 3 can be stably supported by the floating body 5 .

The anti-swing member 11 is desirably arranged at the center of gravity of the floating body 5 and the base portion 7 (the center of the floating body 5 and the base portion 7). In this case, the floating body structure 3 is also arranged above the anti-swing member 11 (at the position of the center of gravity of the floating body 5 and the base portion 7).

The arrangement of the base portion 7 and the floating body 5 is not limited to the example shown in FIG. 2(a). For example, as shown in FIG. 2(b), the number of floating bodies 5 may be three. In this case, the base portion 7 may be a substantially equilateral triangle, and the floating body 5 may be arranged at the vertex of the base portion 7 . By arranging at least three floating bodies 5 at substantially equal intervals in this manner, the base portion 7 and the like can be stably supported.

In addition, the arrangement of the floating structure 3 does not necessarily have to be in the center of the base portion 7 or the like. For example, as shown in FIG. 3( a ), the floating structure 3 may be arranged on one side of the substantially rectangular base portion 7 . In addition, as shown in FIG. 3B, the floating structure 3 may be arranged on one side of the substantially triangular base portion 7 . In this case, by adjusting the amount of ballast introduced into each floating body 5 and adjusting the buoyancy of each floating body 5, the overall balance can be adjusted.

Next, a method for installing the floating structure 3 using the floating structure support structure 1 will be described. The floating structure support structure 1 can be assembled onshore near the ocean where the floating structure 3 is installed. FIG. 4 is a diagram showing a state in which the floating structure support structure 1 is assembled using the temporary pier 19. As shown in FIG.

First, the floating body 5 made of precast concrete is assembled and connected, and the base portion 7 is fixed. The details of the method for assembling the floating body 5 will be described later. Furthermore, the floating structure 3 is assembled and fixed on the base portion 7 . Also, the anti-swing member 11 is connected to the floating structure 3 . When assembling the floating body structure 3, by introducing ballast into the inside of the floating body 5 and the like to sink the floating body 5 (the base portion 7), the work on the upper part becomes easier.

In addition, as described above, the anti-swing member 11 can move up and down below the base portion 7 . When the floating structure support structure 1 is assembled, the anti-swing member 11 is fixed in an elevated state.

Next, as shown in FIG. 5(a), the floating structure support structure 1 is towed to the installation site with the anti-swing member 11 raised. At this time, the ballast of the floating body 5 and the anti-swing member 11 is discharged, and the vessel is towed in a raised state. By doing so, it is possible to prevent the lower part of the floating structure support structure 1 from coming into contact with the seabed.

After the floating structure support structure 1 is towed to the installation site, the anti-swing member 11 is lowered into the sea and fixed (arrow A in the figure). It should be noted that the anti-swaying member 11 need not be lowered to the seabed 22, and may be positioned in the water between the sea surface and the seabed. Also, the floating structure support structure 1 is moored to the seabed 22 by mooring ropes 21 . For example, it may be a tension mooring type.

Here, ballast is introduced into the anti-swing member 11 and substantially all of the internal air is discharged. It should be noted that the ballast introduced into the anti-swing member 11 may not be seawater. The anti-swing member 11 has a role of lowering the center of gravity of the entire floating structure support structure 1 . In addition, since the anti-swing member 11 works as a resistance part in the water against the rocking and vertical movement of the floating structure 3 due to the influence of waves and tides, the anti-swing member 11 functions as an anti-swing damper. can be made In other words, the rocking and vertical movement of the floating structure 3 can be suppressed by the rocking prevention member 11 .

As described above, according to the floating structure support structure 1 of the present embodiment, substantially the entire outer surface is supported by the floating body 5 having a curved surface. can suppress the influence of In addition, since the floating body 5 is long in the vertical direction, for example, if the volume (buoyancy) is the same as in the case of a sphere (that is, the sizes in the vertical direction and the horizontal direction are approximately the same), the cross-sectional area across the water surface can be made smaller. can be done. Therefore, in the vicinity of the water surface, which is most susceptible to waves and tidal currents, an effect similar to that of miniaturizing the floating body 5 can be obtained. For example, it is highly effective in fending off drifting objects.

In addition, by providing a partition 15 inside the floating body 5 and arranging the ballast in the lower part of the floating body 5, the floating body 5 can be stably erected (with its longitudinal direction directed vertically). In addition, the partition 15 can suppress sloshing of ballast water.

Further, since the anti-swing member 11 is connected to the floating structure 3, the center of gravity of the floating structure support structure 1 can be lowered. Further, the rocking prevention member 11 functions as an underwater damper, and can suppress rocking and vertical movement of the floating structure 3 . In order to obtain the effect of preventing rocking by the rocking prevention member 11, the floating structure 3 (or the base portion 7) is not connected to the floating structure 3 (or the base portion 7) by a flexible wire or the like. It is desirable to connect with a rod-shaped member having.

Further, by housing the rod-shaped member 17 inside the column of the wind turbine for offshore wind power generation, the rod-shaped member 17 is not exposed upward even when the anti-swing member 11 is lifted. In addition, it is possible to reliably fix the anti-swing member 11 to the strut both when it is raised and when it is lowered.

In addition, at the connecting portion between the rod-shaped member 17 and the floating structure 3, the force can be reliably transmitted to both in the vertical direction, and the force between the two can be damped in the horizontal direction. A joint structure using a cushioning member or the like that can be For example, when a force due to a tidal current is applied to the anti-swing member 11 in the horizontal direction, the force is attenuated without being transmitted to the floating structure 3, thereby reducing the load on the mooring cable 21. can do. Even in this case, it is possible to reliably secure the damper function for suppressing vertical movement and rocking due to high waves and the like.

In addition, as described above, the floating body 5 is made of precast concrete (for example, having a specific gravity of 2.0 or more). At this time, for example, as shown in FIG. 6(a), the upper curved surface member 23 and the lower curved surface member 25 can be connected via the water cutoff member 27. As shown in FIG. Illustrations of internal partitions, ballast inlets, drain ports, etc. are omitted.

The upper curved surface member 23 and the lower curved surface member 25 are formed by halving a substantially elliptical shape, and the cross-sectional shape at any position is circular, and the maximum diameter is the opening. Both the upper curved surface member 23 and the lower curved surface member 25 are higher than the radius of the opening.

In this case, the connecting portion between the upper curved surface member 23 and the lower curved surface member 25 is formed with a step that can be fitted to each other. can do. At this time, as shown in FIG. 6(b), a tendon 29 may be used to apply prestress. The tendon 29 may be vertically penetrated through the center of the floating body 5 as shown in the figure, or may be arranged inside the thickness of the concrete of the upper curved surface member 23 and the lower curved surface member 25 .

In this way, by combining the upper curved surface member 23 and the lower curved surface member 25 in a watertight manner, an axially symmetrical shape is formed in which the maximum diameter is at the approximate center in the vertical direction and the diameter gradually decreases as it goes up and down. can be done. That is, substantially the entire surface of the floating body 5 can be configured with a curved surface. In addition, as described above, a flat portion or an uneven portion may be formed on a part of the floating body 5 (for example, the upper and lower ends).

Also, as shown in FIG. 7, a ring-shaped member 31 may be added. FIG. 7(a) is a diagram showing a state before assembly, and FIG. 7(b) is a diagram showing the floating body 5 after assembly. In addition, illustration of a partition, a tendon, etc. is abbreviate|omitted.

In the illustrated example, the floating body 5 is composed of an upper curved surface member 23, a lower curved surface member 25, a ring-shaped member 31 sandwiched between the upper curved surface member 23 and the lower curved surface member 25, and the like. That is, the upper curved surface member 23 and the lower curved surface member 25 are joined via the ring-shaped member 31 . The end surface of the ring-shaped member 31 is also formed with steps that can be fitted with the steps formed on the end surfaces of the upper curved surface member 23 and the lower curved surface member 25, so that they can be fitted to each other at their joints. Moreover, a water cutoff member 27 is arranged between each member to ensure water cutoff.

Even if the floating body 5 is formed in this way, it has an axially symmetrical shape in which the maximum diameter is at the approximate center in the vertical direction of the floating body 5, and the diameter gradually decreases toward the upper and lower ends in the vicinity of the upper and lower ends. , and the outer peripheral surface of the floating body 5 can be configured with a curved surface.

Further, as shown in FIGS. 8A and 8B, the number of ring-shaped members 31 sandwiched between the upper curved surface member 23 and the lower curved surface member 25 may be further increased. For example, as shown in the figure, by using a plurality of ring-shaped members 31, the size of the floating body 5 can be increased (lengthened). That is, the size of the floating body 5 can be adjusted according to the number of ring-shaped members 31 between the upper curved surface member 23 and the lower curved surface member 25 .

By using the ring-shaped member 31 in this manner, the floating bodies 5 of a plurality of sizes can be formed by using the upper curved surface member 23 and the lower curved surface member 25 in common. Therefore, it is possible to form the floating body 5 of an appropriate size according to the floating structure by sharing members. At this time, as described above, the length in the vertical direction is longer than the size in the horizontal direction, and the outer surface can be configured with a curved surface over substantially the entire surface, so that the floating body 5 that is less susceptible to the effects of waves and the like can be obtained. .

When the floating body 5 is in use, the portion located near the water surface (intertidal zone) is subject to greater wave force and is more likely to be affected by impact force due to the collision of drifting objects. A precast member (ring-shaped member) made of ultra-high-strength concrete having high durability may also be used.

Note that the shape of the anti-swing member 11 is not particularly limited. For example, similar to the floating body 5, it may have a shape in which almost the entire surface is curved, as shown in FIG. 9(a). In this case, the members may be shared with the floating body 5 .

Further, as shown in FIGS. 9(b) to 9(d), the anti-swing member 11 may have a polygonal cross section with a flat surface. For example, since it is desirable that the anti-swaying member 11 resists the oscillation of the floating structure 3 above, it is desirable that the anti-swaying member 11 has a polygonal cross-sectional shape with a flat surface. In particular, the resistance to vertical movement of the floating structure 3 can be increased by using a triangular shape having flat upper and lower surfaces, a rectangular shape, or the like.

Also, the anti-swing member 11 does not have to be hollow. FIG. 10(a) is a plan view of the anti-swing member 11, and FIG. 10(b) is a front view. As illustrated, the anti-swing member 11 may be a plate-like member having a plurality of water passage holes 14 . By doing so, it is possible to exhibit a damper function against vertical movement due to high waves, etc., and the anti-swing member 11 is less likely to resist horizontal forces such as tidal currents. The load on the mooring cable 21 can be reduced. In this case, by forming the legs 12 on the lower surface side, the anti-swing member can be sunk to the seabed and used as a fishing reef by cutting the bar member 17 after use.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical scope of the present invention is not influenced by the above-described embodiments. It is obvious that a person skilled in the art can conceive various modifications or modifications within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. be understood to belong to

1…………Floating structure support structure 3…………Floating structure 5…………Floating body 7…………Base portion 9a……Lower connecting portion 11……Swing prevention member 13……Space 15…… … Partition 17 …… Rod-shaped member 19 …… Temporary pier 21 …… Mooring cable 22 …… Seabed 23 …… Upper curved surface member 25 …… Lower curved surface member 27 …… Water stop member 29 ………… Tension material 31 …… Ring-shaped member

Claims (7)

A support structure for a floating structure, comprising:
a plurality of floating bodies whose length in the vertical direction is longer than the width in the horizontal direction;
a base portion disposed on the floating body to which the floating structure is fixed;
and
The floating body is made of precast concrete with curved surfaces at least at the upper and lower portions in a cross section in the vertical direction and a space formed therein,
A support structure for a floating structure, characterized in that ballast can be introduced into and discharged from the inside of the floating structure. The floating body has an upper curved surface member, a lower curved surface member, and a ring-shaped member sandwiched between the upper curved surface member and the lower curved surface member,
The upper curved surface member and the lower curved surface member are joined via the ring-shaped member,
2. The floating structure support structure according to claim 1, wherein the size of said floating body can be adjusted according to the number of said ring-shaped members between said upper curved surface member and said lower curved surface member. 3. The floating structure according to claim 1, further comprising: an anti-swing member disposed below the base portion, the anti-swing member being able to descend below the base portion. object support structure. The anti-swing member is made of precast concrete with a hollow inside,
4. The structure for supporting a floating structure according to claim 3, wherein ballast can be introduced into the interior of said anti-swing member. 5. The structure for supporting a floating structure according to claim 3, wherein the anti-swing member is connected to the base portion or the floating structure by a rod member. The floating structure is a wind turbine for offshore wind power generation,
6. The structure for supporting a floating structure according to claim 5, wherein the rod-like member is inserted inside a column of the wind turbine for offshore wind power generation. A floating structure installation method using the floating structure support structure according to claim 3,
a step of towing the floating structure support structure to an installation location with the anti-swing member raised;
lowering the anti-sway member into the sea at an installation site and mooring the floating structure support structure to the seabed;
A method for installing a floating structure, comprising:

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