JP6824464B1 - Marine structure and construction method of marine structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cost while suppressing the discharge of grout to the ocean at the time of construction. SOLUTION: A pile 20 cast on a seabed 11, a leg 31 having an outer diameter smaller than the inner diameter of the pile 20, and a grout filling space 50 formed between the pile 20 and the leg 31 are provided. In the marine structure 10, (1) seawater filled in the grout filling space 50, or (2) grout injected into the grout filling space 50 and diluted with seawater, or (3) grout filling space 50. Further includes an injection unit 59 for injecting a part of the grout injected into the inside of the leg 31. [Selection diagram] FIG. 10

Description

The present invention relates to marine structures and methods for constructing marine structures.

Conventionally, the grout joint structure described in Patent Document 1 below has been known. This grout joint structure is used to support the wind turbines of offshore wind farms.

JP-A-2017-115373

For this type of offshore structure, there is room for improvement in reducing costs while controlling the discharge of grout into the ocean during construction. The discharge of grout into the ocean has not been approved at this time in some areas such as Japan in consideration of the impact on the surrounding environment.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to reduce the cost while suppressing the discharge of grout into the ocean during construction.

<1> The marine structure according to one aspect of the present invention is a grout formed between a pile placed on the sea floor, a leg having an outer diameter smaller than the inner diameter of the pile, and the pile and the leg. In an offshore structure comprising a filling space, (1) seawater filled in the grout filling space, or (2) grout injected into the grout filling space and diluted with seawater, or ( 3) An offshore structure further comprising an injection portion for injecting a part of the grout injected into the grout filling space into the inside of the leg.
<2> In the marine structure according to <1>, the injection portion may adopt a configuration in which seawater is also injected into the legs together with a part of the grout injected into the grout filling space.
<3> In the marine structure according to <1> or <2>, the injection portion adopts a configuration in which the overflowing grout is injected into the inside of the leg when the grout overflows from the grout filling space. You may.

Before injecting grout into the grout filling space, the grout filling space is filled with seawater. When the grout is injected into the grout filling space, first, (1) the seawater filled in the grout filling space is injected into the inside of the leg through the injection portion. As the grout filling space is gradually filled with grout, (2) grout injected into the grout filling space and diluted with seawater (poor quality grout) is injected into the inside of the leg through the injection part. Or (3) a part of the grout (including the supernatant of the grout) injected into the grout filling space is injected into the inside of the leg through the injection part. As a result, while the grout filling space is filled with the grout, the grout injected into the grout filling space is suppressed from being discharged into the ocean.
The outer diameter of the leg is smaller than the inner diameter of the pile. As a result, the cost of marine structures can be reduced.

<4> In the marine structure according to any one of <1> to <3>, the injection portion may adopt a configuration provided above the grout filling space.

The injection section is provided above the grout filling space. Therefore, by injecting a grout having a specific gravity higher than the specific gravity of seawater into the grout filling space, seawater filled in the grout filling space, grout diluted in seawater, etc. can be smoothly discharged from the grout filling space. Can be done.

<5> In the marine structure according to <4>, the injection portion may adopt a configuration provided on a flange plate provided at the upper end of the grout filling space.

The injection portion is provided on a flange plate provided at the upper end of the grout filling space. Therefore, it is not necessary to provide the injection portion on the pile or the leg. Thereby, for example, it is possible to easily secure the strength of the piles and legs.

<6> In the marine structure according to any one of <1> to <5>, a structure is adopted in which a grout seal communicating with the grout filling space is provided around the leg. May be good.

Grout seals are provided around the legs. Therefore, the grout seal can surely prevent the grout from being discharged from the grout filling space into the ocean.

<7> In the marine structure according to any one of <1> to <6>, a partition plate may be installed in the lower part of the grout filling space.

A partition plate is installed at the bottom of the grout filling space. As a result, it is possible to prevent the seabed soil from being mixed into the grout filled in the grout filling space. Therefore, high-quality construction can be realized even on the seabed.
As the partition plate, for example, a steel plate formed in advance in a factory or on the ground can be used. In this case, the partition plate may be simply installed on the seabed at the construction site, for example, and the construction can be completed in a short time. In addition, instead of the partition plate, for example, when a grout as a base for preventing the mixing of the seabed soil is placed and the grout is solidified on the seabed, it is necessary to wait until the solidification is completed. It takes time to construct.

<8> The marine structure according to one aspect of the present invention includes a pile placed on the sea floor, a leg having an outer diameter smaller than the inner diameter of the pile, and a grout formed between the pile and the leg. In an offshore structure including a grout filling space in which a grout flows, which is a filling space, a change portion for changing the direction of the flow of the grout is further provided so that the grout flowing in the grout filling space flows inside the legs. , Characterized by.

The changing part changes the direction of the flow of the grout so that the grout flowing in the grout filling space flows inside the leg. Therefore, the grout that is injected into the grout filling space and flows through the grout filling space is changed in the direction of the flow by the changing portion and flows inside the leg. As a result, while the grout filling space is filled with the grout, the grout injected into the grout filling space is suppressed from being discharged into the ocean.
The outer diameter of the leg is smaller than the inner diameter of the pile. As a result, the cost of marine structures can be reduced.

<9> In the marine structure according to <8>, the modified portion may adopt a configuration provided downstream of the grout flowing through the grout filling space.

The change portion is provided downstream of the grout flowing through the grout filling space. Therefore, when the grout is injected into the grout filling space, the excess grout can be smoothly discharged from the grout filling space while filling the grout filling space with the grout.

<10> In the marine structure according to <8> or <9>, the grout seal provided around the leg and the flange plate provided between the grout filling space and the modified portion are provided. Further, the flange plate may adopt a configuration in which the direction of the flow of the grout flowing through the grout filling space is changed so that a part of the grout flowing through the grout filling space flows inside the grout seal.

The flange plate diverts the flow of grout through the grout filling space so that part of the grout flowing through the grout filling space flows inside the grout seal. Therefore, the excess grout injected into the grout filling space can be discharged not only inside the legs but also inside the grout seal.
When the flange plate is fixed to the leg, the pile may support the leg via the flange plate, for example, by abutting the flange plate against the upper end of the pile when inserting the leg into the pile. it can. In this case, the pile can temporarily receive the legs via the flange plate until the grout is filled in the grout filling space and the grout is solidified.

<11> In the marine structure according to any one of <1> to <10>, the seabed inside the pile is lower than the seabed outside the pile, and the lower end of the leg is the above. A configuration may be adopted that is located below the seabed outside the pile.
<12> In the marine structure according to any one of <1> to <11>, the leg may be a jacket leg.

<13> The method of constructing an offshore structure according to one aspect of the present invention includes a step of driving a pile into the sea floor, a step of inserting a leg having an outer diameter smaller than the inner diameter of the pile into the pile, and a step of inserting the pile into the pile. It is characterized by including a step of providing a passage communicating the grout filling space formed between the stake and the inside of the stake and the inside of the stake, and a step of injecting the grout into the stake filling space.

The grout filling space and the inside of the leg communicate with each other through the passage. Therefore, when the grout is injected into the grout filling space, the seawater filled in the grout filling space and the grout excessively injected into the grout filling space flow into the legs through the passage. As a result, while the grout filling space is filled with the grout, the grout injected into the grout filling space is suppressed from being discharged into the ocean.
The outer diameter of the leg is smaller than the inner diameter of the pile. As a result, the cost of marine structures can be reduced.

<14> In the construction method of the marine structure according to <13>, a configuration may be adopted in which a step of covering the upper part of the pile with a grout seal attached to the leg is further provided.

Cover the top of the stake with a grout seal attached to the leg. Therefore, the grout seal can surely prevent the grout from being discharged from the grout filling space into the ocean.

<15> In the construction method of the marine structure according to <14>, the step of injecting the grout may adopt a configuration in which the grout is injected after the pile is covered with the grout seal.

Inject grout after the pile is covered with grout seal. Therefore, the grout seal can more reliably prevent the grout from being discharged from the grout filling space into the ocean.

<16> In the method for constructing an offshore structure according to any one of <13> to <15>, after the step of driving the pile on the seabed, a step of installing a partition member inside the pile is further added. The configuration may be adopted.

Install partition members inside the pile. As a result, it is possible to prevent the seabed soil from being mixed into the grout filled in the grout filling space. Therefore, high-quality construction can be realized even on the seabed.

According to the present invention, it is possible to reduce the cost while suppressing the discharge of grout into the ocean during construction.

It is a side view which shows the marine structure which concerns on one Embodiment of this invention. It is a vertical cross-sectional view including a jacket which constitutes the marine structure shown in FIG. It is a vertical sectional view of the main part of the marine structure shown in FIG. It is a bottom view of the main part of the marine structure shown in FIG. It is a figure explaining the construction method of the marine structure shown in FIG. 2, and is the figure which shows the 1st step. It is a figure explaining the construction method of the marine structure shown in FIG. 2, and is the figure which shows the 3rd step. It is a figure explaining the construction method of the marine structure shown in FIG. 2, and is the figure which shows the 3rd step. It is a figure explaining the construction method of the marine structure shown in FIG. 2, and is the figure which shows the 4th step. It is an enlarged view of the main part in the figure shown in FIG. 8, and is the figure corresponding to the part shown in FIG. It is an enlarged view of the main part in the figure shown in FIG. 9, and is the figure corresponding to the part shown in FIG. It is a vertical cross-sectional view which shows the marine structure which concerns on 1st modification of 1 Embodiment of this invention, and is the figure which corresponds to FIG. It is a vertical cross-sectional view which shows the marine structure which concerns on the 2nd modification of one Embodiment of this invention, and is the figure which corresponds to FIG. It is a vertical cross-sectional view which shows the marine structure which concerns on the 3rd modification of one Embodiment of this invention, and is the figure which corresponds to FIG.

Hereinafter, the marine structure 10 and the construction method of the marine structure 10 according to the embodiment of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 to 4, the marine structure 10 includes a pile 20 and a jacket 30. Note that FIG. 1 also shows a work vessel 85 used for construction of the marine structure 10.

As shown in FIG. 3, the pile 20 is driven into the seabed 11. The pile 20 is hollow and tubular. The number of stakes 20 is the same as the number of legs 31 described later of the jacket 30. Each pile 20 is driven at a position where the leg 31 is fixed on the seabed 11. The seabed 12 inside the pile 20 (that is, the surface of the seabed soil) is lower than the seabed 12 outside the pile 20. The seabed soil forming the seabed 12 is scraped inside the pile 20. The pile 20 is made of steel.

A plate receiver 21 is provided on the pile 20. The plate receiver 21 has a donut shape (annular shape). The plate receiver 21 is fixed to the pile 20 in advance before the pile 20 is driven into the seabed 11.

A partition plate 22 (partition member) is installed on the plate receiver 21. The plate receiver 21 supports the partition plate 22 from below. The partition plate 22 is simply placed on the plate receiver 21. That is, the partition plate 22 is not fixed to the plate receiver 21 by welding or the like. The outer diameter of the partition plate 22 is smaller than the inner diameter of the pile 20 and larger than the inner diameter of the plate receiver 21. The partition plate 22 is installed below the grout filling space 50, which will be described later. The partition plate 22 is made of steel.

As shown in FIG. 1, the jacket 30 is a fixed marine platform. The jacket 30 is formed in a square pyramid shape as a whole. The jacket 30 is made of steel.
The jacket 30 includes legs 31 (jacket legs 31), a deck 32, and diagonal members 33.

Four legs 31 are provided. Each leg 31 is hollow and tubular.
As shown in FIG. 2, each leg 31 includes a base portion 34 and a main body portion 35.
The base 34 is inserted inside the pile 20. The outer diameter of the base 34 is smaller than the inner diameter of the pile 20. The lower end of the base 34 is located below the seabed 12 outside the pile 20. The upper end of the base 34 is located above the seabed 12 outside the pile 20. The base 34 is substantially parallel to the vertical direction.

As shown in FIG. 3, the lower end of the base 34 is closed by the bottom cap 36. A guide 37 is provided on the bottom cap 36. The guide 37 projects downward from the bottom cap 36. The guide 37 has a weight shape that protrudes downward. The guide 37 guides the base 34 to be inserted into the pile 20.

A flange plate 38 is provided on the base 34. The flange plate 38 is located at the upper end of the grout filling space 50, which will be described later. The flange plate 38 is annular. The flange plate 38 protrudes outward in the radial direction from the outer peripheral surface of the base 34. The outer diameter of the flange plate 38 is larger than the outer diameter of the pile 20. The flange plate 38 is located above the upper end of the pile 20. The flange plate 38 is supported from below by the pile 20.

The flange plate 38 is provided with a cylinder 39. The cylinder 39 rises upward from the outer peripheral edge of the flange plate 38.

As shown in FIG. 2, the main body 35 extends upward from the upper end of the base 34. The main body 35 is longer than the base 34. The main body 35 is inclined with respect to the vertical direction. The main body 35 extends toward the center of the jacket 30 from the bottom to the top. The upper end of the main body 35 is arranged above (on the sea) the sea level 13. The main body 35 is formed with a through hole (not shown) that communicates the inside and the outside of the main body 35. The through hole is formed near the sea level 13.

As shown in FIG. 1, the deck 32 is provided on the top of the jacket 30. The deck 32 is provided at the upper ends of the four legs 31. The deck 32 is supported by four legs 31.
The diagonal member 33 connects the legs 31 adjacent to each other in the horizontal direction. The diagonal member 33 is located below the deck 32. The diagonal member 33 connects the main body 35 of the legs 31 in the horizontal direction. The diagonal member 33 is inclined with respect to the horizontal direction. The diagonal member 33 is hung between the legs 31 adjacent to each other in the horizontal direction. The diagonal members 33 are provided in a plurality of stages (two stages in the illustrated example) in the vertical direction.

Here, as shown in FIG. 3, a grout filling space 50 is formed between the pile 20 and the leg 31. The grout filling space 50 is filled with the grout 51. Four grout filling spaces 50 are formed in total.

The grout filling space 50 includes (1) the inner peripheral surface of the pile 20, (2) the outer peripheral surface of the leg 31 (base 34), (3) the upper surface of the partition plate 22, (4) the lower surface of the bottom cap 36, and (5). It is formed between the lower surfaces of the flange plate 38. The grout 51 is injected into the grout filling space 50, and the grout 51 flows. The pile 20 and the leg 31 are joined by solidifying the grout 51 injected into the grout filling space 50.

A supply pipe 52 is connected to the grout filling space 50. As shown in FIGS. 1 and 2, the supply pipe 52 supplies the grout 51 to the grout filling space 50 from the sea. One supply pipe 52 is provided corresponding to each of the four grout filling spaces 50. A total of four supply pipes 52 are provided. In the illustrated example, the supply pipe 52 is provided with the valve 53, but the valve 53 may not be provided.

Each supply pipe 52 is provided on the jacket 30. The upper end of each supply pipe 52 is located above the deck 32. Each supply pipe 52 penetrates the deck 32 in the vertical direction from above the deck 32, and is then inserted into the inside of the leg 31 from the upper end of the leg 31 (main body 35). Each supply pipe 52 extends from the upper end to the lower end of the leg 31 along the leg 31.

As shown in FIG. 3, each supply pipe 52 penetrates the bottom cap 36 in the vertical direction and is inserted into the grout filling space 50. The lower end of each supply pipe 52 is an injection port for injecting the grout 51 into the grout filling space 50. Each supply pipe 52 is displaced in the radial direction of the leg 31 with respect to the central axis of the leg 31. The supply pipe 52 is not coaxial with the leg 31.

In the grout filling space 50, the grout 51 injected from the supply pipe 52 (injection port) extends from between the bottom cap 36 and the partition plate 22 to the outside in the radial direction of the pile 20, and the inner peripheral surface and legs of the pile 20. It rises through the outer peripheral surface of 31 (see also FIG. 10 described later). In the grout filling space 50, the lower space is upstream and the upper space is downstream.

A grout seal 54 is provided around the leg 31. The grout seal 54 covers the stake 20 and the leg 31 from the outside in the radial direction. The grout seal 54 is hollow and tubular. The grout seal 54 is made of a material that is softer than the pile 20 and the legs 31. The grout seal 54 is, for example, a sheet formed of canvas.

The upper end of the grout seal 54 is fixed to the cylinder 39 (leg 31). The lower end of the grout seal 54 is fixed to the stake 20. The grout seal 54 is fixed to each of the cylinder 39 and the pile 20 by a fixing belt 55. The belt 55 is fastened to the cylinder 39 and the pile 20 from the outside in a state where the grout seal 54 is sandwiched between the outer surfaces of the cylinder 39 and the pile 20.

The inside of the grout seal 54 communicates with the grout filling space 50. In this embodiment, the liner plate 56 is locally arranged between the flange plate 38 and the upper end of the pile 20. The liner plate 56 functions as a spacer. In the flange plate 38, the lower surface of the region where the liner plate 56 is not arranged faces the upper end of the pile 20 with a gap 57. The gap 57 communicates the grout filling space 50 with the inside of the grout seal 54. The thickness of the liner plate 56 and the size of the gap 57 in the vertical direction are also, for example, 50 to 100 mm.

As shown in FIG. 4, the liner plate 56 is arranged only in a part of the flange plate 38 in the circumferential direction. In other words, the flange plate 38 includes a first region 38a provided with the liner plate 56 and a second region 38b not provided with the liner plate 56. The first region 38a is smaller in the circumferential direction than the second region 38b. The circumferential size of the liner plate 56 is less than half (less than half) the circumferential size of the flange plate 38.

As shown in FIG. 3, the liner plate 56 is fixed to the lower surface of the first region 38a of the flange plate 38. The lower surface of the liner plate 56 is in contact with the upper end of the pile 20. The flange plate 38 is supported by the pile 20 via the liner plate 56. The first region 38a is located on the opposite side of the central axis of the leg 31 with the supply pipe 52 in between. In other words, the first region 38a is located radially outside the supply pipe 52.

A temporary receiving rib 40 for reinforcing the first region 38a is provided on the upper surface of the first region 38a of the flange plate 38. The temporary receiving rib 40 projects upward from the flange plate 38. The temporary receiving rib 40 is connected to the outer peripheral surface of the base 34 (leg 31) and the inner peripheral surface of the cylinder 39, respectively. In the illustrated example, a plurality of temporary receiving ribs 40 are provided at intervals in the circumferential direction.

The lower surface of the second region 38b of the flange plate 38 faces the upper end of the pile 20 with the gap 57. The flange plate 38 changes the direction of the flow of the grout 51 flowing through the grout filling space 50 so that a part of the grout 51 flowing through the grout filling space 50 flows inside the grout seal 54. That is, the grout 51 flowing through the grout filling space 50 flows into the grout seal 54 from the grout filling space 50 through the gap 57.

The grout 51 is filled at least up to the upper end of the grout filling space 50. Further, in the present embodiment, the grout 51 is also filled inside the grout seal 54. A part of the inside of the grout seal 54 may be seawater or a grout 51 diluted in seawater. The grout 51 diluted in seawater has a lower specific gravity than the normal grout 51.
Examples of the grout 51 include a material that is curable over time. Examples of the grout 51 include an ultra-high strength grout material.

In the present embodiment, the marine structure 10 is provided with a pipe 58 (passage) that connects the grout filling space 50 and the inside of the legs 31. The pipe 58 is either (1) seawater filled in the grout filling space 50, or (2) grout 51 injected into the grout filling space 50 and diluted with seawater (grout 51 of poor quality), or (3) A part of the grout 51 (including the supernatant of the grout 51) injected into the grout filling space 50 functions as an injection unit 59 for injecting into the inside of the leg 31. The pipe 58 also functions as a changing portion 60 for changing the direction of flow of the grout 51 so that the grout 51 flowing through the grout filling space 50 flows inside the legs 31.

The pipe 58 is provided above the grout filling space 50. The pipe 58 is provided on the flange plate 38. In other words, the flange plate 38 is provided between the grout filling space 50 and the change portion 60. The pipe 58 is provided downstream of the grout 51 flowing through the grout filling space 50.
The pipe 58 is provided in the second region 38b of the flange plate 38. As shown in FIG. 4, a plurality of pipes 58 (three in the illustrated example) are provided at intervals in the circumferential direction.

As shown in FIG. 3, each pipe 58 includes a first portion 58a and a second portion 58b. The first portion 58a penetrates the flange plate 38 in the vertical direction and opens into the grout filling space 50. The first portion 58a extends upward from the flange plate 38. The second portion 58b extends from the upper end of the first portion 58a to the outer peripheral surface of the leg 31 (base 34). The second portion 58b penetrates the leg 31 in the horizontal direction and opens inside the leg 31.
At least a part of each pipe 58 is covered from the outside in the horizontal direction by the cylinder 39. In the illustrated example, the upper end of each pipe 58 is located above the upper end of the cylinder 39.

As shown in FIG. 4, an emergency hole 61 is formed in the second region 38b of the flange plate 38 in addition to the pipe 58. The emergency hole 61 is formed between pipes 58 adjacent to each other in the circumferential direction. The emergency hole 61 is open to the grout filling space 50. A detachable plug 62 is fitted in the emergency hole 61. The stopper 62 closes the emergency hole 61.

The emergency hole 61 is a hole for injecting the grout 51 into the grout filling space 50 in an emergency. Examples of an emergency include a case where grout clogging occurs in the supply pipe 52. In this case, the stopper 62 is removed from the emergency hole 61, and the grout 51 is injected into the grout filling space 50 from the emergency hole 61.

Next, the construction method of the marine structure 10 will be described. This construction method includes the following steps.
(1st step) Step of driving the pile 20 onto the seabed 11 (2nd step) Step of installing the partition plate 22 (partition member) inside the pile 20 (3rd step) Insert the leg 31 of the jacket 30 into the pile 20. Step (4th step) Step of covering the upper part of the pile 20 with the grout seal 54 attached to the leg 31 (5th step) Step of injecting the grout 51 into the grout filling space 50 The above steps are in the order described. It is carried out in the order of the first step to the fifth step).

(1st step)
In the first step, as shown in FIG. 5, the pile 20 is driven into the seabed 11. The pile 20 is positioned on the seabed 11 after being positioned using, for example, a template (not shown).
Further, in the first step, the inside of the pile 20 is washed using the washing machine 80. The washing machine 80 is suspended by, for example, a crane vessel 83. At this time, the seabed soil inside the pile 20 is excavated, and the seabed 12 inside the pile 20 becomes lower than the seabed 12 outside the pile 20. The plate receiver 21 is located on the seabed 12 inside the pile 20.

(Second step)
In the second step, the partition plate 22 is installed inside the pile 20. At this time, for example, the diver 84 drops the partition plate 22 from the upper end of the pile 20 into the inside of the pile 20. The partition plate 22 is received and supported by the plate receiver 21.

(Third step)
In the third step, the legs 31 of the jacket 30 are inserted into the stakes 20 as shown in FIGS. 6 and 7.
In the third step, as shown in FIG. 6, the jacket 30 is transported to the vicinity of the installation position by the transport carrier 81. In addition to the flange plate 38, the supply pipe 52, the pipe 58, and the like, the upper end of the grout seal 54 is fixed to the leg 31 of the jacket 30 by the belt 55. The upper end of the grout seal 54 is fixed to the cylinder 39. The portion other than the upper end of the grout seal 54 is not fixed to the leg 31. The grout seal 54 is wound up, for example, starting from the upper end of the grout seal 54.

In the third step, as shown in FIG. 7, the jacket 30 is lifted from the transport carrier 81 by the crane vessel 83 and suspended at the installation position. At this time, the base 34 of the leg 31 is inserted into the pile 20. When the liner plate 56 (flange plate 38) abuts on the upper end of the pile 20, the legs 31 are supported by the pile 20. At this time, the leg 31 is temporarily received by the pile 20. The inside of the leg 31 is filled with seawater, for example, by infiltrating through the through hole formed in the main body 35. In the illustrated example, the crane vessel 83 is the same as the crane vessel 83 in which the washing machine 80 is suspended in the first step.

When the liner plate 56 (flange plate 38) abuts on the upper end of the pile 20, a grout filling space 50 is formed between the pile 20 and the legs 31. At this time, the grout filling space 50 is filled with seawater.
As described above, the leg 31 is provided with the pipe 58 in advance. Therefore, when the grout filling space 50 is formed, the grout filling space 50 and the inside of the leg 31 are communicated with each other. It can be said that the third step also serves as a step of providing a pipe 58 that connects the grout filling space 50 and the inside of the leg 31.

(4th step)
In the fourth step, as shown in FIG. 8, the upper part of the pile 20 is covered with the grout seal 54 attached to the leg 31. The fourth step is carried out, for example, by the diver 84. The diver 84 first rewinds the grout seal 54 that is wound around the leg 31. The diver 84 fixes the lower end of the rewound grout seal 54 to the stake 20 by the belt 55. As a result, the upper end of the grout seal 54 is fixed to the leg 31, and the lower end of the grout seal 54 is fixed to the pile 20. The inside of the grout seal 54 is filled with seawater.

(Fifth step)
In the fifth step, the grout 51 is injected into the grout filling space 50, as shown in FIGS. 1, 9 and 10.
At this time, first, the work boat 85 moves close to the jacket 30. A mixer 86 and a grout hose 87 are loaded on the work vessel 85.

The mixer 86 stirs the grout 51. The grout 51 is stored in the mixer 86 in a state of having fluidity.
The grout hose 87 is connected to the mixer 86 via a pump (not shown). The grout hose 87 is removable to each supply pipe 52. The grout hose 87 may or may not have a valve. When the supply pipe 52 does not have a valve, it is preferable that the grout hose 87 has a valve.

The inside of each supply pipe 52 is flushed with seawater in parallel with the movement of the work vessel 85 or before and after the movement of the work vessel 85. Flushing may or may not be performed.

Then, as shown in FIG. 10, the grout 51 is supplied to each supply pipe 52, and the grout 51 is injected from each supply pipe 52 into each grout filling space 50.

Then, first, (1) the seawater filled in the grout filling space 50 is injected into the inside of the leg 31 through the pipe 58. When the grout filling space 50 is gradually filled with the grout 51, (2) the grout 51 injected into the grout filling space 50 and diluted with seawater (the grout 51 of poor quality) is transferred to the pipe 58. (3) A part of the grout 51 (including the supernatant of the grout 51) injected into the grout filling space 50 is injected into the inside of the leg 31 through the pipe 58.

That is, the pipe 58 injects seawater into the leg 31 together with a part of the grout 51 injected into the grout filling space 50. Further, when the grout 51 overflows from the grout filling space 50, the pipe 58 injects the overflowing grout 51 into the leg 31. In other words, the pipe 58 changes the direction of the flow of the grout 51 so that the grout 51 flowing through the grout filling space 50 flows inside the leg 31.
Hereinafter, the seawater and the grout 51 (including the diluted grout 51) discharged from the grout filling space 50 as the grout 51 is injected into the grout filling space 50 are referred to as seawater and the like.

The seawater or the like discharged from the grout filling space 50 is injected not only into the inside of the leg 31 through the pipe 58 but also into the inside of the grout seal 54. Seawater or the like is injected into the grout seal 54 through the gap 57 between the upper end of the pile 20 and the flange plate 38. In other words, seawater or the like is branched from the grout filling space 50 into the pipe 58 and the gap 57, and is discharged (injected) into the inside of the leg 31 and the grout seal 54, respectively. When seawater or the like is injected into the grout seal 54, the grout seal 54 expands.
As a result, while the grout filling space 50 is filled with the grout 51, it is suppressed that the grout 51 injected into the grout filling space 50 is discharged into the ocean.

The management of the injection amount of the grout 51 into the grout filling space 50 can be determined based on, for example, the following index.
(Indicator 1) Supply amount of grout 51 to supply pipe 52 (Indicator 2) Degree of swelling of grout seal 54 (Indicator 3) Reaching status of grout 51 into pipe 58

The amount of grout 51 supplied to the supply pipe 52 is measured, for example, by providing a flow meter on the grout hose 87 or the supply pipe 52.
The degree of swelling of the grout seal 54 is confirmed, for example, by visual inspection by the diver 84.
The arrival status of the grout 51 into the pipe 58 is confirmed by visual inspection by the diver 84, for example, when the pipe 58 is made of a transparent material.

Further, in order to confirm the arrival status of the grout 51 into the pipe 58, a confirmation valve 58c may be provided in the pipe 58 as in the marine structure 10A according to the first modification shown in FIG. In the illustrated example, the discharge pipe 58d for obtaining a sample is connected to the pipe 58. The discharge pipe 58d extends upward from the upper end of the first portion 58a of the pipe 58. The upper end of the discharge pipe 58d is a discharge port. The valve 58c is provided in the discharge pipe 58d.
In this case, the valve 58c is opened with a bag (not shown) covered in advance on the discharge port, and the sample is injected into the bag from the discharge port. When the sample is sufficiently injected into the bag, it is collected and, for example, the density of the sample is confirmed to confirm the arrival status of the grout 51 to the pipe 58.

When it is determined that the grout 51 is sufficiently filled in the grout filling space 50 by any of the above indexes, further injection of the grout 51 into the grout filling space 50 is stopped.

When seawater or the like is injected into the legs 31 by the pipe 58, the seawater previously filled inside the legs 31 is, for example, passed through the through hole of the main body 35 according to the volume of the injected seawater or the like. Released into seawater. Since the grout 51 has a higher specific gravity than seawater, the grout 51 injected into the leg 31 moves downward from the pipe 58 inside the leg 31. The through hole is located above the pipe 58 so as to be sufficiently separated from the pipe 58, and the grout 51 injected into the pipe 58 is restricted from being discharged from the through hole.

Further, the preceding material may be injected before the grout 51 is injected into the supply pipe 52. The preceding material is a material from which some components of grout 51 are excluded. Some of the components are excluded from the precursors in order to increase the fluidity of the grout 51. For example, when a material containing an aggregate is used as the grout 51, a material obtained by removing the aggregate from the grout 51 can be used as the preceding material. That is, although the components of the preceding material are common to the components of the grout 51, they have higher fluidity than the grout 51. Therefore, by injecting the preceding material into the supply pipe 52 prior to the grout 51, clogging of the grout 51 in the pipe 58 can be suppressed.

In the present embodiment, four supply pipes 52 are provided, and it is preferable to inject the preceding material into each supply pipe 52 before injecting the grout 51 into each supply pipe 52. When supplying to the supply pipe 52 to be carried out first among the four supply pipes 52, it is preferable that the preceding material is sucked up by the pump to which the grout hose 87 is connected and supplied to the supply pipe 52 through the grout hose 87. .. As a result, clogging of the grout 51 in the pump and the grout hose 87 can be suppressed. The grout 51 may be injected directly into the supply pipe 52 without passing through the pump or the grout hose 87 to the remaining three supply pipes 52.

In this way, even when the preceding material is injected into the supply pipe 52 prior to the grout 51, the preceding material is injected into the grout filling space 50, and the volume of the preceding material and the grout filling space 50 are filled. The seawater that had been used is injected into the pile 20 from the pipe 58. As described above, the components of the preceding material are common to the components of the grout 51. Therefore, the preceding material injected into the grout filling space 50 prior to the grout 51 mixes with the grout 51 when the grout 51 is injected and becomes a part of the grout 51.

By carrying out steps 1 to 5 above, the construction of the marine structure 10 is completed.

As described above, according to the marine structure 10 and the construction method of the marine structure 10 according to the present embodiment, the grout 51 injected into the grout filling space 50 is suppressed from being discharged into the ocean. To.
The outer diameter of the leg 31 is smaller than the inner diameter of the pile 20. As a result, the cost of the marine structure 10 can be reduced.

The pipe 58 is provided downstream of the grout 51 flowing through the grout filling space 50. Therefore, when the grout 51 is injected into the grout filling space 50, the excess grout 51 can be smoothly discharged from the grout filling space 50 while filling the grout filling space 50 with the grout 51.

The pipe 58 is provided above the grout filling space 50. Therefore, by injecting the grout 51 having a specific gravity higher than the specific gravity of the seawater into the grout filling space 50, the seawater filled in the grout filling space 50, the grout 51 diluted with seawater, and the like can be injected from the grout filling space 50. It can be discharged smoothly.

The pipe 58 is provided on the flange plate 38 provided at the upper end of the grout filling space 50. Therefore, it is not necessary to provide the pipe 58 on the pile 20 or the leg 31. Thereby, for example, it is possible to easily secure the strength of the pile 20 and the leg 31.

A grout seal 54 is provided around the leg 31. Therefore, the grout seal 54 can surely prevent the grout 51 from being discharged from the grout filling space 50 into the ocean.

The flange plate 38 changes the direction of the flow of the grout 51 flowing through the grout filling space 50 so that a part of the grout 51 flowing through the grout filling space 50 flows inside the grout seal 54. Therefore, the excess grout 51 injected into the grout filling space 50 can be discharged not only inside the leg 31 but also inside the grout seal 54.

When the flange plate 38 is fixed to the leg 31 as in the present embodiment, when the leg 31 is inserted into the pile 20, for example, by abutting the flange plate 38 against the upper end of the pile 20, the pile 20 However, the legs 31 can be supported via the flange plate 38. In this case, the pile 20 can temporarily receive the legs 31 via the flange plate 38 until the grout 51 is filled in the grout filling space 50 and the grout 51 solidifies.

A partition plate 22 is installed below the grout filling space 50. As a result, it is possible to prevent the seabed soil from being mixed into the grout 51 filled in the grout filling space 50. Therefore, high quality construction can be realized even on the seabed 11.

As the partition plate 22, for example, a steel plate formed in advance in a factory or on the ground can be used. In this case, the partition plate 22 may be simply installed on the seabed 11 at the construction site, for example, and the construction can be completed in a short time. In addition, instead of the partition plate 22, for example, when a grout 51 as a base for preventing the mixing of the seabed ground soil is placed and the grout 51 is solidified on the seabed 11, it waits until the solidification is completed. Necessity arises and construction takes time.

The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

The pipe 58 is not limited to the embodiment shown in the above embodiment.
For example, the pipe 58 may be provided in the cylinder 39 as in the marine structure 10B according to the second modification shown in FIG. The pipe 58 extends from the inner peripheral surface of the cylinder 39 to the outer peripheral surface of the leg 31. The pipe 58 communicates the inside of the grout seal 54 with the inside of the leg 31. In other words, the pipe 58 communicates the grout filling space 50 with the inside of the leg 31 through the inside of the grout seal 54.
In this modification, seawater or the like discharged from the grout filling space 50 is injected into the inside of the grout seal 54 and the inside of the leg 31 through the pipe 58.

Further, in the above embodiment, the pipe 58 functions as the injection unit 59 and the modification unit 60, but the present invention is not limited to this.
For example, as in the marine structure 10C according to the third modification shown in FIG. 13, the opening 58A (passage) may be adopted instead of the pipe 58. The opening 58A communicates the grout filling space 50 with the inside of the leg 31 in the same manner as the pipe 58. The opening 58A penetrates the leg 31 in the horizontal direction (diameter direction). A plurality of openings 58A are provided at intervals in the circumferential direction of the legs 31. The opening 58A functions as an injection portion 59 and a change portion 60, similarly to the pipe 58.

It is preferable that the pipe 58 and the opening 58A (hereinafter collectively referred to as a passage) are located above the height position where the grout 51 is required to be filled at the minimum in the grout filling space 50. The passage is preferably located above the upper end of the pile 20. In this case, the grout 51 can be smoothly filled up to the position reaching the upper end of the pile 20 in the grout filling space 50.

The marine structure 10 is not limited to the jacket 30. The present invention is also applicable to monopile and tripod.

In addition, it is possible to replace the components in the embodiment with well-known components as appropriate without departing from the spirit of the present invention, and the above-described modifications may be appropriately combined.

10 Marine structure 11 Seabed 12 Seabed 20 Pile 22 Plate 30 Jacket 31 Leg 38 Flange plate 50 Grout filling space 51 Grout 54 Grout seal 59 Injection part 60 Change part

Claims (15)

The piles placed on the seabed and
The legs, which have an outer diameter smaller than the inner diameter of the pile and are arranged inside the pile ,
A grout filling space formed between the inner peripheral surface of the pile and the outer peripheral surface of the leg and into which grout is injected from the injection port ,
In marine structures equipped with
A grout that connects the downstream side of the injection port in the grout filling space and the inside of the leg, and is (1) seawater filled in the grout filling space, or (2) injected into the grout filling space. Further provided with an injection portion for injecting the grout diluted in seawater or (3) a part of the grout injected into the grout filling space into the inside of the leg.
A marine structure characterized by that. The injection portion injects seawater into the inside of the leg together with a part of the grout injected into the grout filling space.
The marine structure according to claim 1. The injection portion is provided above the grout filling space.
The marine structure according to claim 1 or 2 . The injection portion is provided on a flange plate provided at the upper end of the grout filling space.
The marine structure according to claim 3 . A grout seal communicating with the grout filling space is provided around the leg.
The marine structure according to any one of claims 1 to 4 . A partition plate is installed at the bottom of the grout filling space.
The marine structure according to any one of claims 1 to 5 . The piles placed on the seabed and
The legs, which have an outer diameter smaller than the inner diameter of the pile and are arranged inside the pile ,
A grout filling space formed between the inner peripheral surface of the pile and the outer peripheral surface of the leg , through which the grout injected from the injection port flows.
In marine structures equipped with
Further provided is a changing portion that connects the downstream side of the injection port in the grout filling space and the inside of the leg, and changes the direction of the flow of the grout so that the grout flowing in the grout filling space flows inside the leg. ,
A marine structure characterized by that. The change portion is provided downstream of the grout flowing through the grout filling space.
The marine structure according to claim 7 . With the grout seal provided around the leg,
A flange plate provided between the grout filling space and the changed portion,
With more
The flange plate changes the direction of the grout flow through the grout filling space so that a part of the grout flowing through the grout filling space flows inside the grout seal.
The marine structure according to claim 7 or 8 . The seabed inside the pile is lower than the seabed outside the pile.
The lower end of the leg is located below the seabed outside the stake.
The marine structure according to any one of claims 1 to 9 . The leg is a jacket leg,
The marine structure according to any one of claims 1 to 10 . Steps to drive piles on the seabed,
A step of inserting a leg having an outer diameter smaller than the inner diameter of the pile into the pile,
A step of providing a passage for communicating the grout filling space formed between the inner peripheral surface of the pile and the outer peripheral surface of the leg and the inside of the leg.
A step of injecting grout into the grout filling space from an injection port and injecting a part of the grout into the inside of the leg through the passage located on the downstream side of the injection port .
A method of constructing an offshore structure characterized by being provided with. Further comprising a step of covering the top of the stake with a grout seal attached to the leg.
The method for constructing an offshore structure according to claim 12 . The step of injecting the grout is to inject the grout after the pile is covered with the grout seal.
The method for constructing an offshore structure according to claim 13 . After the step of driving the pile on the seabed, a step of installing a partition member inside the pile is further provided.
The method for constructing an offshore structure according to any one of claims 12 to 14 .

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