JP2022019818A - Scouring prevention structure and crushed stone unit - Google Patents

Scouring prevention structure and crushed stone unit Download PDF

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JP2022019818A
JP2022019818A JP2021191840A JP2021191840A JP2022019818A JP 2022019818 A JP2022019818 A JP 2022019818A JP 2021191840 A JP2021191840 A JP 2021191840A JP 2021191840 A JP2021191840 A JP 2021191840A JP 2022019818 A JP2022019818 A JP 2022019818A
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crushed stone
unit
stone unit
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prevention structure
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JP7221366B2 (en
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聡 稲垣
Satoshi Inagaki
雄二 新原
Yuji Niihara
英広 藤田
Hidehiro Fujita
一星 梅津
Issei Umezu
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Kajima Corp
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Kajima Corp
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Abstract

PROBLEM TO BE SOLVED: To provide a scouring prevention structure capable of efficiently building a scouring prevention structure, and a scouring prevention method.
SOLUTION: In order to build a scouring prevention structure, a filter layer is formed on the ground around a monopile, but the installation of the filter layer is not mandatory. In a crushed stone unit 13a, stones 28a with a small particle size similar to that of the filter layer are put in the bottom of the bag body 27. In a shown crushed stone unit 13b, a net-like sheet 28b, which is expected to be clogged with sand to the same extent as the filter layer, is laid on the bottom of the bag body 27. In the case the filter layer is not formed, the above crushed stones units may be used.
SELECTED DRAWING: Figure 10
COPYRIGHT: (C)2022,JPO&INPIT

Description

本発明は、袋体に砕石類を充填した砕石ユニット及びこれを用いた洗掘防止構造に関するものである。 The present invention relates to a crushed stone unit in which a bag is filled with crushed stones and a scouring prevention structure using the crushed stone unit.

従来、洋上風力発電設備などの基礎を水中に設置する構造物では、水の流れによって水底面に発生する洗掘現象から構造物を保護するために構造物の周囲に洗掘防止工を設置している。洗掘防止工としては、袋体の中に砕石などの塊状物を充填した砕石ユニットが用いられる(例えば、特許文献1参照)。 Conventionally, in structures where the foundation of offshore wind power generation equipment is installed underwater, scouring prevention work is installed around the structure to protect the structure from the scouring phenomenon that occurs on the bottom of the water due to the flow of water. ing. As the scouring prevention work, a crushed stone unit in which a crushed stone or the like is filled in a bag is used (see, for example, Patent Document 1).

砕石ユニットは水底面に設置すると平面が円形に近い形となるため、隣り合う砕石ユニット同士の間に隙間ができる。隙間があると洗掘防止工としての役割を十分に果たさない恐れがあり、一般的には砕石ユニットを水底面に複数層に重ねて設置し上段と下段の砕石ユニットを噛み合わせて隙間を解消している。 When the crushed stone unit is installed on the bottom of the water, the plane becomes almost circular, so there is a gap between the adjacent crushed stone units. If there is a gap, it may not play a sufficient role as a scouring prevention work, so in general, the crushed stone unit is installed in multiple layers on the bottom of the water and the upper and lower crushed stone units are engaged to eliminate the gap. is doing.

特許第5570965号公報Japanese Patent No. 5570965

しかしながら、砕石ユニットを複数層に重ねて設置しようとすると、良質な石材等が大量に必要であり、施工時間も長くかかる。近年はより大型の洋上風力発電設備が採用されており、基礎も大きくなることが予想されるため、砕石ユニットを必要最小設置範囲に効率的に設置することが課題となっている。また、洗掘防止構造では、砕石ユニットは、フィルター層の上部に配置されるため、まず、地盤上にフィルター層を形成する必要がある。 However, when trying to install the crushed stone unit in a plurality of layers, a large amount of high-quality stone material or the like is required, and the construction time is long. In recent years, larger offshore wind power generation facilities have been adopted, and it is expected that the foundation will also be large, so it is an issue to efficiently install the crushed stone unit within the required minimum installation range. Further, in the scour prevention structure, since the crushed stone unit is arranged on the upper part of the filter layer, it is necessary to first form the filter layer on the ground.

本発明は、前述した問題点に鑑みてなされたものであり、その目的とすることは、洗掘防止構造を効率的に構築することができる洗掘防止構造等を提供することである。 The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a scouring prevention structure or the like capable of efficiently constructing a scouring prevention structure.

前述した目的を達成するために第1の発明は、袋体に砕石類を充填した砕石ユニットを用いた洗掘防止構造であって、水底の地盤に設置された基礎の外周面に接するように複数の前記砕石ユニットが環状に並べて配置されるとともに、基礎の外周面に接するように配置された前記砕石ユニットの外周の全周に、さらに地盤の所定の範囲に前記砕石ユニットが配置され、少なくとも一部の前記砕石ユニットは、前記袋体の下層に相対的に小さい粒径の石が入れられ、上層に相対的に大きな粒径の石が入れられていることを特徴とする洗掘防止構造である。 In order to achieve the above-mentioned object, the first invention is a scouring prevention structure using a crushed stone unit in which a crushed stone is filled in a bag body so as to be in contact with the outer peripheral surface of a foundation installed on the ground of the bottom of the water. A plurality of the crushed stone units are arranged side by side in a ring shape, and the crushed stone unit is arranged all around the outer circumference of the crushed stone unit arranged so as to be in contact with the outer peripheral surface of the foundation, and further, the crushed stone unit is arranged in a predetermined range of the ground. Some of the crushed stone units have a scouring prevention structure characterized in that a stone having a relatively small particle size is contained in the lower layer of the bag body and a stone having a relatively large particle size is contained in the upper layer. Is.

また、第1の発明は、袋体に砕石類を充填した砕石ユニットを用いた洗掘防止構造であって、 水底の地盤に設置された基礎の外周面に接するように複数の前記砕石ユニットが環状に並べて配置されるとともに、基礎の外周面に接するように配置された前記砕石ユニットの外周の全周に、さらに地盤の所定の範囲に前記砕石ユニットが配置され、少なくとも一部の前記砕石ユニットは、前記袋体の底部に、砂の目詰まりが見込める網状のシートが敷かれていることを特徴とする洗掘防止構造であってもよい。 The first invention is a scouring prevention structure using a crushed stone unit in which a crushed stone is filled in a bag, and the plurality of the crushed stone units are in contact with the outer peripheral surface of a foundation installed on the ground of the bottom of the water. The crushed stone units are arranged side by side in a ring shape, and the crushed stone units are arranged on the entire circumference of the outer periphery of the crushed stone unit arranged so as to be in contact with the outer peripheral surface of the foundation, and further in a predetermined range of the ground, and at least a part of the crushed stone units. May have a scouring prevention structure characterized in that a net-like sheet that is expected to be clogged with sand is laid on the bottom of the bag body.

隣接する前記砕石ユニットは、互いに重なり部分が設けられて、複数の前記砕石ユニットが隙間なく配置されてもよい。複数の前記砕石ユニットが、平面視で略六角形状となるように並べて配置されることが望ましい。隣接する前記砕石ユニットは、互いに重なり部分が設けられて、複数の前記砕石ユニットが隙間なく配置されることが望ましい。 The adjacent crushed stone units may be provided with overlapping portions, and a plurality of the crushed stone units may be arranged without a gap. It is desirable that the plurality of the crushed stone units are arranged side by side so as to have a substantially hexagonal shape in a plan view. It is desirable that the adjacent crushed stone units are provided with overlapping portions so that a plurality of the crushed stone units are arranged without gaps.

複数の前記砕石ユニットの平面視での設置範囲の外接円の径と内接円の径との平均値が、前記基礎の径の3倍から5倍であることが望ましい。
これにより、洗掘防止効果を確保しつつ、砕石ユニットの設置範囲を縮小することができる。
It is desirable that the average value of the diameter of the circumscribed circle and the diameter of the inscribed circle in the installation range of the plurality of stone crushing units in a plan view is 3 to 5 times the diameter of the foundation.
As a result, the installation range of the crushed stone unit can be reduced while ensuring the effect of preventing scouring.

水底地盤上にフィルター層が配置されずに、水底地盤上に前記砕石ユニットが設置されてもよい。
これにより、フィルター層を用いずに、水底の地盤の砂の吸出しを防ぎ、砕石ユニットによる洗掘防止効果を高めることができる。
The crushed stone unit may be installed on the bottom ground without the filter layer being arranged on the bottom ground.
As a result, it is possible to prevent the sand from being sucked out from the ground at the bottom of the water without using a filter layer, and to enhance the effect of preventing scouring by the crushed stone unit.

第2の発明は、洗掘防止構造に用いられる砕石ユニットであって、袋体と、前記袋体に充填される石と、を具備し、前記袋体の下層に相対的に小さい粒径の石が入れられ、上層に相対的に大きな粒径の石が入れられていることを特徴とする砕石ユニットである。 The second invention is a crushed stone unit used for a scouring prevention structure, which comprises a sack body and stones filled in the sack body, and has a particle size relatively small in the lower layer of the sack body. It is a crushed stone unit characterized in that stones are put in it and stones with a relatively large particle size are put in the upper layer.

また、第2の発明は、洗掘防止構造に用いられる砕石ユニットであって、袋体と、前記袋体に充填される石と、を具備し、前記袋体の底部に、前記袋体の網目よりも相対的に小さい網目の網状のシートが敷かれていることを特徴とする砕石ユニットであってもよい。 The second invention is a crushed stone unit used for a scouring prevention structure, which comprises a bag body and stones filled in the bag body, and the bottom of the bag body has the bag body. It may be a crushed stone unit characterized in that a mesh-like sheet having a mesh relatively smaller than the mesh is laid.

前記袋体の底部であって、平面視の略中央付近に線材が接合され、前記線材によって、前記砕石ユニットを上方から吊り上げ可能であることが望ましい。平坦な場所に置かれた際の、前記砕石ユニットの径L1と高さH1との比L1/H1は、2.5以上であることが望ましい。 It is desirable that the wire rod is joined to the bottom portion of the bag body in the vicinity of substantially the center in a plan view, and the crushed stone unit can be lifted from above by the wire rod. It is desirable that the ratio L1 / H1 of the diameter L1 and the height H1 of the crushed stone unit when placed on a flat place is 2.5 or more.

本発明によれば、洗掘防止構造を効率的に構築することができる洗掘防止構造等を提供することができる。 According to the present invention, it is possible to provide a scouring prevention structure or the like that can efficiently construct a scouring prevention structure.

洗掘防止構造31の鉛直方向の断面を示す図。The figure which shows the cross section in the vertical direction of the scour prevention structure 31. 洗掘防止構造31を上方から見た図。The figure which looked at the scour prevention structure 31 from above. 砕石ユニットの概要を示す図。The figure which shows the outline of the crushed stone unit. 砕石ユニット9付近の拡大図。Enlarged view of the vicinity of the crushed stone unit 9. 砕石ユニット9の設置範囲を示す図。The figure which shows the installation range of a crushed stone unit 9. 砕石ユニット7、9を配置する工程を示す図。The figure which shows the process of arranging the crushed stone units 7 and 9. 設置用治具25を示す図。The figure which shows the installation jig 25. 設置用治具25aを示す図。The figure which shows the installation jig 25a. 砕石ユニット9の設置範囲をさらに縮小した例を示す図。The figure which shows the example which further reduced the installation range of the crushed stone unit 9. フィルター層の働きを内在した砕石ユニットを示す図。The figure which shows the crushed stone unit which had the function of a filter layer inside.

以下、図面に基づいて本発明の好適な実施形態について詳細に説明する。
図1は洗掘防止構造31の鉛直方向の断面を示す図である。図2は洗掘防止構造31を上方から見た図であり、図1のA-A線断面図である。図3は砕石ユニットの概要を示す図である。図4は図1に示す砕石ユニット9付近の拡大図である。
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing a vertical cross section of the scouring prevention structure 31. FIG. 2 is a view of the scouring prevention structure 31 as viewed from above, and is a cross-sectional view taken along the line AA of FIG. FIG. 3 is a diagram showing an outline of the crushed stone unit. FIG. 4 is an enlarged view of the vicinity of the crushed stone unit 9 shown in FIG.

図1、図2に示すように、洗掘防止構造31は、水底の地盤3に設置された基礎であるモノパイル1の周囲に構築される。洗掘防止構造31は、フィルター層5、第1の砕石ユニット7、第2の砕石ユニット9、第3の砕石ユニット11等からなる。 As shown in FIGS. 1 and 2, the scouring prevention structure 31 is constructed around a monopile 1 which is a foundation installed on the ground 3 at the bottom of the water. The scouring prevention structure 31 includes a filter layer 5, a first crushed stone unit 7, a second crushed stone unit 9, a third crushed stone unit 11, and the like.

フィルター層5はモノパイル1の周囲の地盤3上に砕石を敷設して形成される。第1の砕石ユニット7は、フィルター層5上にモノパイル1の外周面に接するように配置される。第2の砕石ユニット9は、フィルター層5上の砕石ユニット7の外周側に平面視で略六角形状となるように並べて配置される。第3の砕石ユニット11は、砕石ユニット7と砕石ユニット9との境界上に配置される。ケーブル33は、砕石ユニット11同士の間、砕石ユニット7と砕石ユニット9との間に通される。フィルター層5は、少なくとも砕石ユニット7および砕石ユニット9が設置される範囲に設置されればよい。 The filter layer 5 is formed by laying crushed stone on the ground 3 around the monopile 1. The first crushed stone unit 7 is arranged on the filter layer 5 so as to be in contact with the outer peripheral surface of the monopile 1. The second crushed stone unit 9 is arranged side by side on the outer peripheral side of the crushed stone unit 7 on the filter layer 5 so as to have a substantially hexagonal shape in a plan view. The third crushed stone unit 11 is arranged on the boundary between the crushed stone unit 7 and the crushed stone unit 9. The cable 33 is passed between the crushed stone units 11 and between the crushed stone unit 7 and the crushed stone unit 9. The filter layer 5 may be installed at least in a range where the crushed stone unit 7 and the crushed stone unit 9 are installed.

図3に示すように、砕石ユニット7、9、11は、いずれもラッセル網等を用いた袋体27に砕石類を充填し縫合したものである。砕石ユニット7、9、11は、袋体の27の底部であって、平面視の略中央付近に線材29が接合される。線材29は、波浪による袋体27内での砕石類の移動を抑制し、砕石類の移動による袋体27の摩耗を防止する。 As shown in FIG. 3, the crushed stone units 7, 9, and 11 are all made by filling a bag body 27 using a Russell net or the like with crushed stones and suturing them. The crushed stone units 7, 9 and 11 are the bottoms of 27 of the bag body, and the wire rod 29 is joined to the vicinity of substantially the center in a plan view. The wire rod 29 suppresses the movement of crushed stones in the bag body 27 due to waves, and prevents the bag body 27 from being worn due to the movement of the crushed stones.

砕石ユニット9、11の袋体27の容量は砕石ユニット7の袋体27の容量よりも大きい。例えば、砕石ユニット9、11の袋体27内には8tの砕石類が充填され、砕石ユニット7の袋体27内には4tの砕石類が充填される。平坦な場所に置かれた砕石ユニット7、9、11は上方から見ると略円形であり、砕石ユニット9、11の水平投影面積は砕石ユニット7の水平投影面積より大きい。 The capacity of the bag 27 of the crushed stone units 9 and 11 is larger than the capacity of the bag 27 of the crushed stone unit 7. For example, the bag 27 of the crushed stone units 9 and 11 is filled with 8 tons of crushed stones, and the bag 27 of the crushed stone unit 7 is filled with 4 tons of crushed stones. The crushed stone units 7, 9 and 11 placed on a flat place are substantially circular when viewed from above, and the horizontally projected area of the crushed stone units 9 and 11 is larger than the horizontally projected area of the crushed stone unit 7.

図4に示すように平坦な場所に置かれた砕石ユニット9の径L1と高さH1との比L1/H1は、砕石ユニット9が容易に変形可能である程度に大きい(例えば図に示す例では比が2.5以上)ものとする。砕石ユニット7、11についても同様である。このような扁平な砕石ユニット7、9、11を用いることにより、図4に示す砕石ユニット9の例のように、砕石ユニット7、9、11を、隣接する他の砕石ユニット7、9、11との間に隙間が生じないように重なり部分を設けて配置することができる。 As shown in FIG. 4, the ratio L1 / H1 of the diameter L1 and the height H1 of the crushed stone unit 9 placed on a flat place is large to some extent so that the crushed stone unit 9 can be easily deformed (for example, in the example shown in the figure). The ratio shall be 2.5 or more). The same applies to the crushed stone units 7 and 11. By using such flat crushed stone units 7, 9 and 11, the crushed stone units 7, 9 and 11 can be combined with other adjacent crushed stone units 7, 9 and 11 as in the example of the crushed stone unit 9 shown in FIG. An overlapping portion can be provided and arranged so that a gap does not occur between the two.

図5は、砕石ユニット9の設置範囲を示す図である。図5に示す例では、砕石ユニット9の平面視での設置範囲の外接円15の径19と内接円17の径21との平均値を径23としたとき、径23がモノパイル1の径13の5倍である。ここで、外接円15とは平面視で砕石ユニット9の設置範囲の全体を含む最小円であり、内接円17とは砕石ユニット9の設置範囲に全体が含まれる最大円である。フィルター層5は、例えば、水が透過可能なアスファルトマット等で構成され、少なくとも砕石ユニット9および砕石ユニット11が設置される範囲に形成される。 FIG. 5 is a diagram showing an installation range of the crushed stone unit 9. In the example shown in FIG. 5, when the average value of the diameter 19 of the circumscribed circle 15 and the diameter 21 of the inscribed circle 17 in the installation range of the crushed stone unit 9 in a plan view is the diameter 23, the diameter 23 is the diameter of the monopile 1. It is 5 times as much as 13. Here, the circumscribed circle 15 is the minimum circle including the entire installation range of the crushed stone unit 9 in a plan view, and the inscribed circle 17 is the maximum circle including the entire installation range of the crushed stone unit 9. The filter layer 5 is made of, for example, an asphalt mat that allows water to pass through, and is formed at least in a range in which the crushed stone unit 9 and the crushed stone unit 11 are installed.

次に、洗掘防止構造31の構築方法について説明する。図6は砕石ユニット7、9を配置する工程を示す図である。 Next, a method of constructing the scouring prevention structure 31 will be described. FIG. 6 is a diagram showing a process of arranging the crushed stone units 7 and 9.

洗掘防止構造31を構築するには、まず、モノパイル1の周囲の地盤3上にフィルター層5を形成する。また、フィルター層5の形成と前後して、モノパイル1からフィルター層5上に延伸するケーブル33(図2)を配置する。その後、図6(a)に示すように、複数の砕石ユニット7をモノパイル1の外周面に接するように環状に並べて配置する。砕石ユニット7は、例えばクレーンで1個ずつ吊り下げて水底に配置されてもよいが、装置や治工具等を用いて複数個の砕石ユニット7を一括して設置してもよい。例えば、モノパイル1から離した状態で、モノパイル1に沿って、複数の砕石ユニット7を吊り降ろし、設置の際に、モノパイル1側に移動させて、砕石ユニット7をモノパイル1に接触するように配置してもよい。 In order to construct the scouring prevention structure 31, first, the filter layer 5 is formed on the ground 3 around the monopile 1. Further, before and after the formation of the filter layer 5, a cable 33 (FIG. 2) extending from the monopile 1 onto the filter layer 5 is arranged. After that, as shown in FIG. 6A, a plurality of crushed stone units 7 are arranged in an annular shape so as to be in contact with the outer peripheral surface of the monopile 1. The crushed stone unit 7 may be suspended one by one by a crane and arranged on the bottom of the water, or a plurality of crushed stone units 7 may be collectively installed by using a device, a jig or the like. For example, in a state of being separated from the monopile 1, a plurality of crushed stone units 7 are suspended along the monopile 1, moved to the monopile 1 side at the time of installation, and the crushed stone unit 7 is arranged so as to be in contact with the monopile 1. You may.

次に、図6(b)に示すように、複数の砕石ユニット9を砕石ユニット7の外周に平面視で略六角形状となるように隙間なく並べて配置する。砕石ユニット7と砕石ユニット9とは寸法が異なるため、砕石ユニット7と砕石ユニット9との間には隙間が生じる。この隙間を塞ぐため、図2に示すように砕石ユニット11を砕石ユニット7と砕石ユニット9との境界部に配置する。 Next, as shown in FIG. 6B, a plurality of crushed stone units 9 are arranged side by side on the outer periphery of the crushed stone unit 7 so as to have a substantially hexagonal shape in a plan view. Since the crushed stone unit 7 and the crushed stone unit 9 have different dimensions, a gap is formed between the crushed stone unit 7 and the crushed stone unit 9. In order to close this gap, the crushed stone unit 11 is arranged at the boundary between the crushed stone unit 7 and the crushed stone unit 9 as shown in FIG.

図7は設置用治具25を示す図、図8は設置用治具25aを示す図である。砕石ユニット9は、鋼製の設置用治具25、25a等にフック(図示せず)を用いて複数個ずつ吊り下げて水底に配置される。 FIG. 7 is a diagram showing the installation jig 25, and FIG. 8 is a diagram showing the installation jig 25a. A plurality of crushed stone units 9 are suspended from steel installation jigs 25, 25a, etc. using hooks (not shown) and arranged on the bottom of the water.

設置用治具25を用いて砕石ユニット9を設置する場合には、例えば、図7(a)に示すように、設置用治具25に、複数の砕石ユニット9を、隣接する砕石ユニット9同士の高さを変えて、適切な重なりが得られるような間隔をおいて一列に吊り下げる。そして、水中に砕石ユニット9を沈下させて同時にフック(図示せず)を外す。これにより、図7(b)に示すように複数の砕石ユニット9を重なり部分を設けて1列に配置することができる。 When the crushed stone unit 9 is installed using the installation jig 25, for example, as shown in FIG. 7A, a plurality of crushed stone units 9 are placed on the installation jig 25, and the adjacent crushed stone units 9 are connected to each other. Change the height of the jigs and hang them in a row at intervals so that proper overlap can be obtained. Then, the crushed stone unit 9 is subsided in water and the hook (not shown) is removed at the same time. As a result, as shown in FIG. 7B, a plurality of crushed stone units 9 can be arranged in one row with overlapping portions.

設置用治具25aを用いて砕石ユニット9を場合する際には、例えば、図8(a)に示すように、設置用治具25aに、複数の砕石ユニット9を、隣接する砕石ユニット9同士の高さを変えて、適切な重なりが得られるような間隔をおいて2列に吊り下げる。そして、水中に砕石ユニット9を沈下させて各列毎にフックを外す。これにより、図8(b)に示すように複数の砕石ユニット9を重なり部分を設けて2列に配置することができる。 When the crushed stone unit 9 is used with the installation jig 25a, for example, as shown in FIG. 8A, a plurality of crushed stone units 9 are attached to the installation jig 25a, and the adjacent crushed stone units 9 are connected to each other. Change the height of the jigs and hang them in two rows at intervals so that an appropriate overlap can be obtained. Then, the crushed stone unit 9 is submerged in water and the hook is removed for each row. As a result, as shown in FIG. 8B, a plurality of crushed stone units 9 can be arranged in two rows with overlapping portions.

このように、本実施形態では、砕石ユニット9より水平投影面積の小さい砕石ユニット7を用いることにより、モノパイル1の外周付近に砕石ユニット7をなるべく隙間なく配置することができる。また、砕石ユニット7の外側に砕石ユニット9を平面視で略六角形状となるように重なり部分を設けて並べることにより、砕石ユニット9を確実に隙間なく配置することができる。さらに、砕石ユニット11を配置することにより、大きさの異なる砕石ユニット7と砕石ユニット9とを並べることで生じた隙間を塞ぐことができる。これにより、砕石ユニット7、9を1層で構成して砕石ユニット7と砕石ユニット9との隙間を砕石ユニット11で塞ぐだけの効率的な配置が実現され、石材の使用量の削減や工期の短縮が可能となる。 As described above, in the present embodiment, by using the crushed stone unit 7 having a smaller horizontal projection area than the crushed stone unit 9, the crushed stone unit 7 can be arranged as close as possible to the outer periphery of the monopile 1. Further, by arranging the crushed stone units 9 on the outside of the crushed stone unit 7 by providing overlapping portions so as to have a substantially hexagonal shape in a plan view, the crushed stone units 9 can be reliably arranged without gaps. Further, by arranging the crushed stone unit 11, it is possible to close the gap created by arranging the crushed stone unit 7 and the crushed stone unit 9 having different sizes. As a result, an efficient arrangement is realized in which the crushed stone units 7 and 9 are composed of one layer and the gap between the crushed stone unit 7 and the crushed stone unit 9 is closed by the crushed stone unit 11, reducing the amount of stone used and shortening the construction period. It can be shortened.

本実施形態では、砕石ユニット9の平面視での設置範囲の外接円15の径19と内接円17の径21との平均の径23をモノパイル1の径13の5倍とすることにより、洗掘防止効果を確保しつつ砕石ユニット9の設置範囲を縮小することができる。 In the present embodiment, the average diameter 23 of the diameter 19 of the circumscribed circle 15 and the diameter 21 of the inscribed circle 17 in the installation range of the crushed stone unit 9 in a plan view is set to 5 times the diameter 13 of the monopile 1. The installation range of the crushing stone unit 9 can be reduced while ensuring the scouring prevention effect.

但し、砕石ユニット9の平面視での設置範囲は上記した範囲に限らず、砕石ユニット9の平面視での設置範囲の外接円の径と内接円の径との平均の径23がモノパイル1の径13の3倍から5倍であればよい。図9は、砕石ユニット9の設置範囲をさらに縮小した例を示す図である。図9(a)は平均の径23aをモノパイル1の径13の4倍とした例である。図9(b)は平均の径23bをモノパイル1の径13の3倍とした例である。フィルター層は少なくとも砕石ユニット9および砕石ユニット11が設置される範囲に形成されればよく、図9(a)(b)に示す例ではフィルター層5a、5bは砕石ユニット9および砕石ユニット11が設置される範囲より広い範囲に形成される。このように砕石ユニット9およびフィルター層の平面視での設置範囲をさらに縮小した場合でも洗掘防止効果を得ることができる。これら3~5倍の範囲で洗掘防止工が機能することは、波浪を対象とした縮尺1/30スケールの水理模型実験にて確認されている。 However, the installation range of the crushed stone unit 9 in a plan view is not limited to the above range, and the average diameter 23 of the diameter of the circumscribed circle and the diameter of the inscribed circle in the installation range of the crushed stone unit 9 in a plan view is monopile 1. It may be 3 to 5 times the diameter of 13. FIG. 9 is a diagram showing an example in which the installation range of the crushed stone unit 9 is further reduced. FIG. 9A is an example in which the average diameter 23a is four times the diameter 13 of the monopile 1. FIG. 9B is an example in which the average diameter 23b is three times the diameter 13 of the monopile 1. The filter layer may be formed at least within the range in which the crushed stone unit 9 and the crushed stone unit 11 are installed. In the example shown in FIGS. 9A and 9B, the filter layers 5a and 5b are provided with the crushed stone unit 9 and the crushed stone unit 11. It is formed in a wider range than it is. As described above, even when the installation range of the crushed stone unit 9 and the filter layer in a plan view is further reduced, the scouring prevention effect can be obtained. It has been confirmed in a 1/30 scale hydraulic model experiment for waves that the scouring prevention work works in the range of 3 to 5 times.

また、砕石ユニット9を水底に配置するための設置用治具は、上記したものに限らない。設置用治具に吊り下げる砕石ユニット9の列数、1列あたりの砕石ユニット9の数は、砕石ユニット9の配置計画に応じて決定すればよい。また、各砕石ユニット9の吊り下げ高さやフックを外すタイミングは、一部の砕石ユニット9のフックを外した時の設置用治具の位置ずれや回転を考慮して決定すればよい。 Further, the installation jig for arranging the crushed stone unit 9 on the bottom of the water is not limited to the above. The number of rows of crushed stone units 9 suspended from the installation jig and the number of crushed stone units 9 per row may be determined according to the arrangement plan of the crushed stone units 9. Further, the hanging height of each crushed stone unit 9 and the timing of removing the hook may be determined in consideration of the positional deviation and rotation of the installation jig when the hook of a part of the crushed stone unit 9 is removed.

さらに、フィルター層5の設置は必須ではない。図10は、フィルター層の働きを内在した砕石ユニットを示す図である。図10(a)に示す砕石ユニット13aは袋体27の底にフィルター層程度の小さい粒径の石28aを入れたものであり、図10(b)に示す砕石ユニット13bは、袋体27の底にフィルター層と同程度の砂の目詰まりが見込める網状のシート28bを敷いたものである。フィルター層5を設置しない場合は、図10に示すような砕石ユニットを用いてもよい。 Further, the installation of the filter layer 5 is not essential. FIG. 10 is a diagram showing a crushed stone unit having an inherent function of a filter layer. The crushed stone unit 13a shown in FIG. 10 (a) is formed by putting a stone 28a having a particle size as small as that of a filter layer in the bottom of the bag body 27, and the crushed stone unit 13b shown in FIG. 10 (b) is the bag body 27. A net-like sheet 28b, which is expected to be clogged with sand to the same extent as the filter layer, is laid on the bottom. When the filter layer 5 is not installed, a crushing stone unit as shown in FIG. 10 may be used.

以上、添付図面を参照しながら、本発明に係る好適な実施形態について説明したが、本発明はかかる例に限定されない。当業者であれば、本願で開示した技術的思想の範疇内において、各種の変更例又は修正例に想到し得ることは明らかであり、それらについても当然に本発明の技術的範囲に属するものと了解される。 Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, the present invention is not limited to such an example. It is clear that a person skilled in the art can come up with various modified examples or modified examples within the scope of the technical idea disclosed in the present application, and these also naturally belong to the technical scope of the present invention. Understood.

例えば、水底の地盤に設置されたジャケット式基礎のアンカー杭などに本発明を適用してもよい。 For example, the present invention may be applied to an anchor pile of a jacket-type foundation installed on the ground of the bottom of the water.

1………モノパイル
3………地盤
5、5a、5b………フィルター層
7、9、11、13a、13b………砕石ユニット
19、21、23、23a、23b………径
15、17………円
25、25a………設置用治具
27………袋体
28a………石
28b………シート
29………線材
31………洗掘防止構造
33………ケーブル
1 ………… Monopile 3 ………… Ground 5, 5a, 5b ………… Filter layer 7, 9, 11, 13a, 13b ………… Crushed stone unit 19, 21, 23, 23a, 23b ………… Diameter 15, 17 ……… Circle 25, 25a ……… Installation jig 27 ………… Bag body 28a ………… Stone 28b ………… Sheet 29 ………… Wire rod 31 ………… Scour prevention structure 33 ………… Cable

Claims (10)

袋体に砕石類を充填した砕石ユニットを用いた洗掘防止構造であって、
水底の地盤に設置された基礎の外周面に接するように複数の前記砕石ユニットが環状に並べて配置されるとともに、基礎の外周面に接するように配置された前記砕石ユニットの外周の全周に、さらに地盤の所定の範囲に前記砕石ユニットが配置され、
少なくとも一部の前記砕石ユニットは、前記袋体の下層に相対的に小さい粒径の石が入れられ、上層に相対的に大きな粒径の石が入れられていることを特徴とする洗掘防止構造。
It is a scouring prevention structure that uses a crushed stone unit in which the bag is filled with crushed stones.
A plurality of the crushed stone units are arranged in a ring shape so as to be in contact with the outer peripheral surface of the foundation installed on the ground of the water bottom, and the entire circumference of the outer circumference of the crushed stone unit arranged so as to be in contact with the outer peripheral surface of the foundation. Furthermore, the crushed stone unit is placed in a predetermined area of the ground, and the crushed stone unit is placed.
At least a part of the crushed stone unit is characterized in that a stone having a relatively small particle size is contained in the lower layer of the bag body and a stone having a relatively large particle size is contained in the upper layer. Construction.
袋体に砕石類を充填した砕石ユニットを用いた洗掘防止構造であって、
水底の地盤に設置された基礎の外周面に接するように複数の前記砕石ユニットが環状に並べて配置されるとともに、基礎の外周面に接するように配置された前記砕石ユニットの外周の全周に、さらに地盤の所定の範囲に前記砕石ユニットが配置され、
少なくとも一部の前記砕石ユニットは、前記袋体の底部に、砂の目詰まりが見込める網状のシートが敷かれていることを特徴とする洗掘防止構造。
It is a scouring prevention structure that uses a crushed stone unit in which the bag is filled with crushed stones.
A plurality of the crushed stone units are arranged in a ring shape so as to be in contact with the outer peripheral surface of the foundation installed on the ground of the water bottom, and the entire circumference of the outer circumference of the crushed stone unit arranged so as to be in contact with the outer peripheral surface of the foundation. Furthermore, the crushed stone unit is placed in a predetermined area of the ground, and the crushed stone unit is placed.
At least a part of the crushed stone unit has a scouring prevention structure in which a net-like sheet that can be expected to be clogged with sand is laid on the bottom of the bag body.
隣接する前記砕石ユニットは、互いに重なり部分が設けられて、複数の前記砕石ユニットが隙間なく配置されることを特徴とする請求項1又は請求項2に記載の洗掘防止構造。 The scouring prevention structure according to claim 1 or 2, wherein the adjacent crushed stone units are provided with overlapping portions thereof, and a plurality of the crushed stone units are arranged without a gap. 複数の前記砕石ユニットが、平面視で略六角形状となるように並べて配置されたことを特徴とする請求項1から請求項3のいずれかに記載の洗掘防止構造。 The scouring prevention structure according to any one of claims 1 to 3, wherein the plurality of the crushed stone units are arranged side by side so as to have a substantially hexagonal shape in a plan view. 水底地盤上にフィルター層が配置されずに、水底地盤上に複数の前記砕石ユニットが設置されることを特徴とする請求項1から請求項4のいずれかに記載の洗掘防止構造。 The scouring prevention structure according to any one of claims 1 to 4, wherein a plurality of the crushed stone units are installed on the bottom ground without arranging the filter layer on the bottom ground. 複数の前記砕石ユニットの平面視での設置範囲の外接円の径と内接円の径との平均値が、前記基礎の径の3倍から5倍であることを特徴とする請求項1から請求項5のいずれかに記載の洗掘防止構造。 From claim 1, the average value of the diameter of the circumscribed circle and the diameter of the inscribed circle in the installation range of the plurality of stone crushing units in a plan view is 3 to 5 times the diameter of the foundation. The scouring prevention structure according to any one of claim 5. 洗掘防止構造に用いられる砕石ユニットであって、
袋体と、
前記袋体に充填される石と、
を具備し、
前記袋体の下層に相対的に小さい粒径の石が入れられ、上層に相対的に大きな粒径の石が入れられていることを特徴とする砕石ユニット。
A crushed stone unit used for scouring prevention structures,
With the bag body,
The stones filled in the bag and
Equipped with
A crushed stone unit characterized in that a stone having a relatively small particle size is contained in the lower layer of the bag body and a stone having a relatively large particle size is contained in the upper layer.
洗掘防止構造に用いられる砕石ユニットであって、
袋体と、
前記袋体に充填される石と、
を具備し、
前記袋体の底部に、前記袋体の網目よりも相対的に小さい網目の網状のシートが敷かれていることを特徴とする砕石ユニット。
A crushed stone unit used for scouring prevention structures,
With the bag body,
The stones filled in the bag and
Equipped with
A crushed stone unit characterized in that a mesh-like sheet having a mesh relatively smaller than the mesh of the bag is laid on the bottom of the bag.
前記袋体の底部であって、平面視の略中央付近に線材が接合され、前記線材によって、前記砕石ユニットを上方から吊り上げ可能であることを特徴とする請求項7又は請求項8記載の砕石ユニット。 The crushed stone according to claim 7 or 8, wherein a wire rod is joined to the bottom portion of the bag body in the vicinity of substantially the center in a plan view, and the crushed stone unit can be lifted from above by the wire rod. unit. 平坦な場所に置かれた際の、前記砕石ユニットの径L1と高さH1との比L1/H1は、2.5以上であることを特徴とする請求項7から請求項9のいずれかに記載の砕石ユニット。 According to any one of claims 7 to 9, the ratio L1 / H1 of the diameter L1 and the height H1 of the crushed stone unit when placed on a flat place is 2.5 or more. The described crushed stone unit.
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