JP2016084660A - Foundation structure of off-shore wind turbine generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foundation structure of an off-shore wind turbine generator, which can sufficiently exert wave resistance and achieve a reduction in construction cost and an increase in working efficiency.SOLUTION: In a foundation structure of an off-shore wind turbine generator, a gravity-type caisson is installed on a seabed, and a wind turbine structure is arranged in an upper part of the caisson. The caisson is formed in a polygonal cylindrical shape from a polygonal bottom and an exterior wall part vertically erected from an outer peripheral part of each side of the bottom.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a foundation structure of an offshore wind power generator.

  In recent years, it has been attracting attention to install offshore wind power generators in shallow waters. However, strong wind-powered sea areas that provide high power generation capacity are inevitably high waves and deep sea areas, and the seabed is often harder than sea areas where waves are calm. As a foundation structure of an offshore wind power generation apparatus in view of these points, a gravity-type foundation using a caisson having a square or circular plan view has been widely put into practical use.

  A substantially circular bottom plate, a substantially cylindrical lower side wall rising from the outer periphery of the bottom plate, a substantially cylindrical upper side wall having a smaller diameter than the lower side wall, and a general truncated cone connecting the lower side wall and the upper side wall. A so-called flask-type caisson composed of a tapered side wall is also disclosed and known (for example, see Patent Document 1).

JP 2006-322400 A

  However, when the plan view is a rectangular caisson, a relatively large wave force acts on the outer wall surface of each side of the caisson as compared with a circular caisson. For this reason, it is necessary to take measures such as constructing a large-scale foundation structure in order to exhibit wave resistance, resulting in increased construction costs.

  In the case of a circular caisson, it is very troublesome to form a circular formwork when constructing the caisson, and work efficiency is poor. Usually, the earth pressure by the filling material filled in the caisson acts as an axial tensile force on the outer wall of the caisson, so a partition wall is formed inside the caisson to ensure the proof strength. However, it is known that when the outer wall is circular, the partitioning work is very troublesome and the workability is poor. There is a configuration in which no partition is formed in the caisson, but in that case, it is necessary to use a steel material or prestressed concrete for the outer wall in order to ensure the proof stress, which increases costs.

  In the case of a flask-type caisson, the buoyancy is also small because the hollow volume in the caisson is smaller than that of a square or circular caisson. After the caisson is formed by a floating dock or a dry dock (dry dock), the caisson is moved to the installation position of the offshore wind turbine generator. At that time, if caisson's buoyancy can be used, it can be towed by tug and installed by a small hoist. However, when the buoyancy is small like a flask-type caisson, it is necessary to prepare a large hoist ship separately, which causes a problem that the construction cost increases and the work efficiency is poor.

  An object of one embodiment of the present invention is made in view of the above problems, and provides a basic structure of an offshore wind power generator that can sufficiently exhibit wave resistance, and can realize reduction in construction cost and improvement in work efficiency. It is to provide.

The above issues
A gravitational caisson is installed on the seabed ground, and a wind turbine structure is arranged on the upper part of the caisson, and is a basic structure of an offshore wind power generator,
The caisson is formed in a polygonal cylindrical shape by a polygonal bottom and an outer wall portion standing upright from an outer peripheral portion of each side of the bottom, and the basic structure of the offshore wind power generator Can be solved.

  ADVANTAGE OF THE INVENTION According to this invention, the foundation structure of the offshore wind power generator which can fully exhibit wave resistance and can implement | achieve reduction of construction cost and improvement of work efficiency can be provided.

It is the elevation which showed the schematic structure of the foundation structure of the offshore wind power generator concerning the embodiment of the present invention. It is a top view of FIG. It is an expanded elevation view of the caisson main-body part which comprises the foundation structure of the offshore wind power generator concerning embodiment of this invention. FIG. 4 is a plan cross-sectional view taken along the line II in FIG. 3. It is the partially expanded elevation view which showed schematic structure of the foundation structure of the offshore wind power generator concerning other embodiment of this invention. It is II-II arrow plane sectional drawing of the caisson main-body part shown in FIG.

  Hereinafter, embodiments of the foundation structure of the offshore wind power generator according to the present invention will be described. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description thereof will be simplified or omitted as appropriate. The drawings are not intended to show the relative ratio between members or parts. Accordingly, specific dimensions can be determined by one skilled in the art in light of the following non-limiting embodiments.

[First Embodiment]
FIG. 1 is an elevational view showing a schematic configuration of a foundation structure of an offshore wind power generator 1 according to an embodiment of the present invention. FIG. 2 shows a plan view of FIG. FIG. 3 is an enlarged elevation view of the caisson body 3 constituting the foundation structure of the offshore wind power generator 1 according to the embodiment of the present invention. FIG. 4 is a cross-sectional view taken along the line II of FIG.

  The basic structure using the caisson of the offshore wind power generation apparatus 1 of the present embodiment is installed in the open ocean with a large power generation capacity of the offshore wind power generation and is far away from the coastline, and a relatively shallow sea area (with a water depth of 10 m to 20 m). ) Is preferably installed.

  This offshore wind power generator 1 has a basic structure 2 having a gravity caisson main body 3 and a basic structure in which a windmill structure 8 is disposed on the upper part of the caisson main body 3. The basic structure of this embodiment is comprised by the said basic | foundation part 2, and the point is demonstrated concretely below.

  The above-described foundation portion 2 includes a caisson main body portion 3 installed on the seabed ground at a construction site, a rooting block 4 sequentially disposed on the outer periphery of the caisson main body portion 3, and a covering block 5.

  As shown in FIGS. 3 and 4, the caisson main body 3 of the present embodiment has an octagonal shape with a bottom portion 31 that is octagonal in plan view and an outer wall portion 32 that stands vertically from the outer peripheral portion of each side of the bottom portion 31. It is formed in a cylindrical shape. The caisson main body 3 is not provided with a tapered outer wall unlike the conventional flask-type caisson main body, and the outer wall 32 is erected in a vertical state. Therefore, the hollow volume formed in the caisson main body 3 is larger than that of the conventional flask type. The large hollow volume of the caisson body 3 means that a large buoyancy can be obtained when floating on the ocean. Therefore, when towing the caisson main body 3 to the construction site, the caisson main body 3 can be moved to the installation site by utilizing the buoyancy of the caisson main body 3. Then, there is no need to prepare a separate large hoist ship, and it is possible to tow by tug, and even to install work with an existing hoist ship usually deployed offshore.

  Incidentally, it is preferable that the volume in the hollow part of the caisson main body 3 needs a volume necessary for the caisson main body 3 to float without assistance by buoyancy.

  The caisson body 3 is made of reinforced concrete (RC structure), and a formwork is formed in the land yard behind the quay of the harbor where the wave conditions are mild near the installation site, in the dry dock, or on the floating dock. The concrete is then laid in layer order.

  Incidentally, the caisson main body 3 shown in the figure has a height of, for example, 12 m to 17 m and a width of 20 m to 25 m. However, it is not limited to this, and is changed as appropriate depending on the wind turbine structure 8 and the condition of the seabed ground. Incidentally, it is preferable that the caisson main body 3 has a height at which an upper portion of the caisson main body 3 is exposed from the water surface in a normal ocean state when installed on the seabed ground (see FIG. 1).

  As described above, the caisson main body 3 of the present embodiment is formed in an octagon in plan view. Therefore, the wave force acting on the outer wall portion 32 on each side of the caisson main body 3 is remarkably reduced as compared with a square caisson, and sufficient wave resistance can be exhibited. Incidentally, although the caisson main body 3 having an octagonal shape in plan view is shown, the present invention is not limited to this and may be a polygon such as a hexagon.

  Further, as shown in FIG. 4, the caisson main body 3 having the above-described structure preferably has a lattice-shaped partition wall 33 formed in the hollow portion. As the partition wall 33, a plurality of partition walls 33S are arranged to connect the vertices facing each of the octagonal vertices a to h in order to ensure the yield strength. In addition, a partition wall 33C orthogonal to the outer wall portion 32 is also disposed at a center position between the vertices (a center position between the partition walls 33S). In particular, the inclined wall 32T constituting the octagonal inclined surface (tapered surface) of the outer wall portion 32 is also provided with a partition wall 33T orthogonal to the inclined wall 32T at the center position between the apexes. A plurality of chambers are formed in the caisson main body 3 by the partition walls 33, and the filling material 7 is filled in each chamber (see FIG. 3). Therefore, the axial tensile force of earth pressure due to the filling material 7 acting on the outer wall portion 32 by the partition wall 33 can be relaxed.

  Construction of the partition wall 33 of the present embodiment is very easy compared to a circular caisson main body because the caisson main body 3 is octagonal in plan view and each side is linear. However, when the size of the caisson main body 3 is small, it is not necessary to construct the partition wall 33.

  The caisson main body 3 having the above-described structure is towed by a normal type hoist ship, and is submerged on the seabed ground at the installation location. After the subsidence, a high specific gravity material is used as a filling material 7 in the hollow part (in each room by the partition wall 33). It is thrown. Thereafter, as shown in FIG. 3, the lid concrete 34 and the upper concrete 35 are placed, and the pedestal 36 is installed. And the windmill structure 8 is constructed | assembled on the upper part of the pedestal 36. FIG. The wind turbine structure 8 can be implemented by a structure normally used in a wind power generator.

  As the basic structure of the present embodiment, the caulk body part 3 and the above-described root block 4 and covering block 5 are configured. The root block 4 and the covering block 5 are also implemented as part of scouring measures. Accordingly, crushed stones and rubble are previously added to the installed seabed ground to form the foundation mound K, and then the surface of the foundation mound K is leveled. In the illustrated example, the leveling portion is indicated by the symbol N.

  Moreover, it is preferable that the following rooting block 4 and covering block 5 are installed after the caisson main body 3 is installed and the lid concrete 34 is placed.

  The root hardening block 4 is a block made of concrete, and is laid on the outer peripheral ground of the caisson main body 3 installed on the leveling point N (foundation mound K) to support the caisson main body 3. . Moreover, it is preferable that the overall shape in which the plurality of root-set blocks 4 are laid is juxtaposed so that the plan view is an octagon like the caisson main body 3.

  Further, a covering block 5 is disposed at a further outer peripheral position of the root hardening block 4. The covering block 5 exhibits a function of covering the ground in order to prevent the ground from collapsing due to wave force in the vicinity of the seabed ground at the installation location.

The total width of the root block 4 and the covering block 5 is preferably formed wider than the width of the caisson body 3, but is not limited thereto.
Moreover, it is preferable that the scouring prevention mat 6 is disposed at the lower end portion of the covering block 5 above the outer edge portion of the leveling portion N.

  Incidentally, in the illustrated basic structure, a part or all of the bottom 31 of the caisson main body 3 is embedded in the leveling point N (in the basic mound K) and embedded below the bottom surface of the root block 4. The configuration.

<How to build>
Below, the construction method of the foundation structure of the offshore wind power generator 1 which concerns on the 1st Embodiment of this invention is demonstrated briefly.

  First, in a land production yard (for example, dry dock, floating dock), the process of assembling a mold for forming the octagonal outer shape of the caisson main body 3 and placing concrete is repeated for each layer in a desired size. The caisson body 3 is manufactured.

  Then, the caisson main body 3 is moved offshore from the production yard, floated on the sea, and towed to the installation site of the offshore wind turbine generator by tugboat. That is, since the caisson main body 3 of the present invention has an octagonal cylindrical shape, sufficient buoyancy can be expected, so a large hoist ship is not required, and towing work can be performed by tug. In addition, the installation work can be carried out sufficiently with the existing hoist ship. Therefore, the construction cost can be reduced and the working efficiency can be improved.

  By the way, the seabed ground where the caisson main body 3 is installed has a foundation mound K formed in advance by crushed stone and rubble, and the surface is leveled by a diver and a leveling point N is formed. .

  Next, in the installation sea area, liquid or the like is injected into the hollow part of the caisson main body 3 (in each chamber by the partition wall 33), the caisson main body 3 is leveled and submerged on the point N, and then on the submarine ground (base mound). K)). And the filling material 7 is filled in the hollow part (each room | chamber interior) of the caisson main-body part 3, and the cover concrete 34 is laid. At this time, since the upper portion of the caisson main body 3 is exposed from the water surface as described above, the filling of the filling material 7 and the placement of the lid concrete 34 can be easily performed.

  Thereafter, the caulking block 4 and the covering block 5 are installed on the outer peripheral position of the caisson main body 3 using a hoist ship. At this time, the entire width of the root block 4 and the covering block 5 is set to be wider than the width of the caisson main body 3 so that the supporting force of the caisson main body 3 can be surely exhibited.

  As described above, the upper concrete 35 is placed on the top of the lid concrete 34 of the caisson main body 3 installed on the seabed ground by a concrete mixer ship, and a coating agent is applied to the concrete surface as a salt damage prevention measure.

  After that, the offshore wind power generator 1 can be constructed by installing the pedestal 36 on the upper part of the upper concrete 35 and constructing the wind turbine structure 8 such as the tower portion and the wind turbine portion sequentially.

  In this way, it is possible to construct the offshore wind power generator 1 and its foundation structure that can exhibit wave resistance, reduce work costs, and improve work efficiency in a relatively shallow sea area.

[Second Embodiment]
Next, the basic structure of the offshore wind power generator 1 ′ according to the second embodiment of the present invention will be described. FIG. 5 is a partially enlarged elevation view showing a schematic configuration of the foundation structure of the offshore wind power generator 1 ′ according to the second embodiment of the present invention. 6 is a cross-sectional plan view of the caisson main body shown in FIG.

  The foundation 20 constituting the foundation structure of the present embodiment is implemented in order to reliably obtain the support force of the caisson main body when the ground strength of the seabed ground at the installation site is weak or when the wave force is considerably strong, for example. Is done. Since the basic basic structure is substantially the same as that of the first embodiment, overlapping points will be omitted, and differences will be mainly described.

  The foundation part 20 of the present embodiment is also basically a caisson body part 300 installed on the seabed ground of the construction site, a rooting block 4 arranged in order on the outer periphery of the caisson body part 300, and a covering block 5. It has.

  However, in the case of this embodiment, the point which the footing 37 is installed in the caisson main-body part 300 is different from 1st Embodiment.

  As shown in FIGS. 5 and 6, the caisson main body 300 of the present embodiment is provided with a footing 37 having a shape protruding from the outer wall 32 (including the inclined wall 32 </ b> T) at a lower position. The footing 37 has a height capable of effectively supporting the caisson main body 300 and is made of RC similarly to the caisson main body 300. That is, the footing 37 is formed by forming a form frame constituting the footing, arranging the concrete, and placing the concrete at the time of manufacturing the caisson main body 300 described above. The footing 37 in the illustrated example is formed along the shape of the outer peripheral portion constituting each side of the caisson main body 300, and its plan view is an octagon like the caisson main body 300. However, it is not limited to this, and it may be a rectangle, a circle, a hexagon, an ellipse, or the like.

<How to build>
The construction method of the foundation structure of the offshore wind power generator 1 ′ according to the second embodiment is substantially the same as the construction method described in the first embodiment.

  The difference is that the caisson body 300 used has a footing 37.

  As described above, the basic structure of the offshore wind power generator according to the present embodiment has the caisson main body portions 3 and 300 that support the windmill structure 8 in a cylindrical shape that is octagonal in plan view. Therefore, the wave force acting on the outer wall surface of the caisson main body 3 or 300 is smaller than that of the quadrangle, and the wave resistance can be sufficiently exhibited. Moreover, since the plan view of the caisson main body parts 3 and 300 is octagonal and each side is linear, the construction of the partition wall 33 installed in the hollow part of the caisson main body parts 3 and 300 is applied to the circular caisson main body part. Compared with this, the construction becomes easier.

  Further, the caisson main body portions 3 and 300 of the present embodiment are configured such that the outer wall portion 32 stands upright without being provided with a tapered outer wall unlike the conventional flask-type caisson main body. Therefore, the hollow volume formed in the caisson main body portions 3 and 300 is larger than that of the conventional flask type. The large hollow volume of the caisson body parts 3 and 300 means that a large buoyancy is obtained when floating on the ocean. Therefore, when towing the caisson main body 3, 300 to the installation site, the buoyancy of the caisson main body 3, 300 can be utilized. Then, it is not necessary to prepare a separate large hoist ship and can be towed by a tug that is usually deployed offshore. Furthermore, the installation work is sufficient with an existing hoist ship, and it is possible to reduce the construction cost and improve the work efficiency.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific embodiments described above, and various modifications are possible within the scope of the gist of the present invention described in the claims. It can be modified and changed.

DESCRIPTION OF SYMBOLS 1, 1 'Offshore wind power generator 2, 20 Base part 3,300 Caisson main-body part 31 Bottom part 32 Outer wall part 32T Inclined wall 33 (33S, 33C, 33T) Bulkhead 34 Cover concrete 35 Upper concrete 36 Bedestal 37 Footing 4 Rooting block 5 Covering block 6 Anti-scouring mat 7 Filling material 8 Windmill structure K Foundation mound N Leveling point

Claims (7)

A gravitational caisson is installed on the seabed ground, and a wind turbine structure is arranged on the upper part of the caisson, and is a basic structure of an offshore wind power generator,
The caisson is formed in a polygonal cylindrical shape by a polygonal bottom and an outer wall that stands vertically from the outer peripheral part of each side of the bottom, and has a basic structure for an offshore wind turbine generator .   2. The offshore according to claim 1, wherein a plurality of rooting blocks are laid on the outer peripheral ground of the caisson installed on the seabed ground so that the plan view is circular or polygonal. The basic structure of a wind turbine generator.   The foundation structure of the offshore wind power generator according to claim 1 or 2, wherein the polygon is an octagon.   The foundation structure of the offshore wind power generator according to any one of claims 1 to 3, wherein a part or all of the bottom portion of the caisson is embedded in the seabed ground.   The foundation structure of the offshore wind power generator according to any one of claims 1 to 3, wherein a footing having a shape protruding from the outer wall portion is provided at a position below the caisson.   The foundation structure of the offshore wind power generator according to any one of claims 1 to 5, wherein the hollow portion of the caisson has a volume that allows the caisson to exert buoyancy by itself.   The base structure of the offshore wind power generator according to any one of claims 1 to 6, wherein partition walls are arranged in a lattice shape in the hollow portion of the caisson.

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