JPH0619126B2 - Cast-in-floating breakwater structure - Google Patents

Description

Description: [Industrial field of use] The present invention relates to a structure for a floatable breakwater that is installed in the sea to form a breakwater.

[Prior art] Currently, in order to protect the natural coast facing the open sea from erosion due to waves, concrete caisson and concrete
Jetty and breakwaters with piled blocks are generally used.

However, these jetties and breakwaters are not suitable for coasts with steep seabed gradients or soft grounds, because their installation depth is limited. Moreover, if the height of the jetty or the breakwater is higher than the sea level, it not only causes an aesthetic problem that it easily damages the natural landscape, but also hinders the circulation of seawater and hinders seawater exchange. Therefore, it is difficult to apply it to marine recreation and aquaculture facilities that are expected in the future.

In order to solve these problems, recently, as a breakwater of a submerged type, for example, as shown in FIG. 8, a flexible membranous structure 40 is installed on the seabed 41, and FIG. As shown in Fig. 6, a large number of cylinders 51 containing pneumatic rubber bags 52 are mounted on a horizontal plate 50, and the horizontal plate 50 is supported by anchors 54 by mooring lines 53 in a state of floating in the sea. Has been done.

However, each of these breakwaters has a complicated structure and requires diving work on the seabed before installation.
The installation work requires a great deal of labor, and in the latter case, there is a drawback in that it requires labor for transportation to the site.

[Problems to be Solved by the Invention] The technical problem of the present invention is that the structure for a floating breakwater has a simple structure, excels in transportability to the site, and can be easily installed by simply putting it into the sea. To provide things.

[Means for Solving the Problems] In order to solve the above problems, the structure for a floating breakwater according to the present invention is formed by a flexible film material so as to be expandable and contractible in the axial direction and held in an extended state. The present invention is characterized in that a cylindrical floating body provided with a holding means is connected to a throw-in type anchor by a mooring line and installed at a desired depth in water.

Further, the structure for a floating breakwater of the present invention comprises a cylindrical floating body formed by a flexible film material so as to be capable of expanding and contracting in the axial direction, and is connected to individual throw-in anchors by mooring ropes at least at both ends. It is also characterized in that it is configured to be installed at a desired depth.

[Operation] In the above-mentioned structure, the floating body is compressed in the axial direction, folded small and transported to the installation site, and then the floating body is extended and put into a predetermined installation position from the ship.
It is installed in the sea with the axis of the floating body facing the direction of wave propagation.
Therefore, the transportation work and the installation work of the structure are very simple, and the structure can be easily installed without being affected by the water depth, the state of the seabed ground, the topography, and the like.

In addition, since it is a submerged type, it does not impair the natural landscape and can be used very effectively for effective use of ocean space, prevention of coastal erosion, expansion of recreation areas, securing fishing grounds, etc.

Embodiments Embodiments of the present invention will be described in detail below with reference to the drawings.

The structure 1 shown in FIG. 1 is configured by connecting a floating body 2 having a smaller specific gravity than seawater to an anchor 4 by a mooring line 3.

The floating body 2 has a cylindrical shape with different diameters at both ends, and a flexible film material 6 having high durability and made of synthetic fiber, synthetic rubber, synthetic resin or the like is formed into a desired cylindrical shape.
Ring-shaped supporting bones 7 and 8 made of a lightweight and durable material such as fiber reinforced plastic (FRP) are attached at appropriate positions, and a spiral elastic bone 9 made of the same material is attached.
Is attached to the floating body 2 so that the floating body 2 can be held in an extended state during installation in the sea. A holding means 11 composed of a stretched bone that is detachably stretched between 8 and 8 is provided. The holding means 11 is not limited to the tensioned bone as shown, but may have any structure as long as it can restrict the contraction of the floating body 2.

Each of the supporting bones 7 of the floating body 2 is provided with a mounting portion 7a of the mooring cable 3, and one end of the mooring cable 3 is fixed to each mounting portion 7a, and the other ends of the mooring cable 3 are common. It is fastened to the fastening metal 4a of the seabed anchor 4 of FIG. The anchor 4 is a throw-in type concrete anchor that is installed on the seabed by being put into the sea from the ship. When the floating body 2 and the anchor 4 are connected by the mooring lines 3 as described above, it is not always necessary to connect the mooring lines 3 to all the supporting bones 7, and it is possible to connect the mooring lines 3 to appropriate supporting bones 7 according to the acting wave force. The mooring line 3 may be tied.

The structure 1 having the above-mentioned configuration is transported to the installation site offshore of the coastline in a small folded state by releasing the holding means 11 and compressing the floating body 2 in the axial direction, and the floating body 2 is then constructed there.
Is stretched and held in the stretched state by the holding means 11, and is put into the sea together with the anchor 4, so that the axis of the floating body 2 is changed in the wave propagation direction (usually the coastline 12 as shown in FIGS. 1 and 2). And the large diameter part.
One or a plurality of floating bodies 2a are installed in the sea with the floating body 2 facing the offshore and at a desired depth from the sea surface, which constitutes a floating breakwater.

In the floating wave breakwater, the floating body 2 resists the phase fluctuations of the waves and the wave energy is dissipated, so that the wave height is effectively attenuated. Further, since the floating body 2 is installed in the sea, it does not impair the natural landscape, and by setting the installation water depth appropriately, it is possible to avoid obstacles to navigation of the ship.

The above-mentioned floating wave breakwater is required to have a wave breaking effect of about 50%, but even if the conditions such as the shape of the shoreline and the seabed, the water depth, etc. differ depending on the place where it is installed, those conditions will be met. It is possible to obtain a desired wave-dissipating effect by increasing or decreasing the number of structures 1 installed accordingly.

The preferred shape and dimensions of the structure 1, which varies depending on the installation conditions or the like, generally, the diameter D ₁ of the large diameter portion 2a of the floating body 2 is 2 to 3 m, diameter D ₂ of the small diameter portion 2b is D ₁ / 2 to D ₁
/ 10 m, the length B is about 1/2 to 1/6 of the wavelength L, and
The submerged depth d from the sea surface on the large diameter portion 2a side of the floating body 2 is within the range of 1/10 to 1/2 of the water depth h, and the minimum distance e between the floating bodies 2 is D ₁ /
It is preferably ₂ to D ₁ .

The structure 1 may be installed with the large diameter portion 2a of the floating body 2 facing the coastline 12 side, as opposed to the case of FIG. 2, or as shown in FIG. It is also possible to install them by combining those which are opposite to each other.

Further, the floating body 2 can be installed in a plurality of layers in the depth direction in the various modes described above. FIG. 4 shows the case where the upper and lower floating bodies 2 are arranged at the same position in the vertical direction, and FIG. 5 shows the case where they are arranged in the different positions vertically. In this case, the upper and lower floating bodies 2 may be integrally connected as shown in FIG. Further, when the floating bodies 2 are installed in a plurality of upper and lower layers in this way, the upper and lower floating bodies 2 may have the same orientation or opposite orientations.

FIG. 6 shows another embodiment of the structure, which is different from the one shown in FIG. 1 in that the holding means 11 for holding the floating body 2 in the extended state is directly attached to the floating body 2. Structure 21
Then, without directly attaching such holding means to the floating body 22, both ends of the flexible floating body 22 are connected to the individual throw-in anchors 24, 24 by mooring lines 23, and these anchors 24, 24 are used. The difference is that the floating bodies 22 are restrained from contracting in the axial direction by being separately supported. Therefore, the anchors 24, 24 constitute a holding means. The structure of the floating body 22 is different from that shown in FIG. 1 only in that a holding means is not provided.
Other configurations are substantially the same.

The shape of the floating bodies 2 and 22 is not limited to the cylindrical shape in which the diameters of both end portions are different and the diameter is continuously changed as described above. For example, as in the floating body 32 shown in FIG. , Any shape such as a drum shape in which the central portion gradually decreases in diameter, or conversely a drum shape in which the central portion gradually increases in diameter, or a cylindrical shape having a uniform diameter can be formed. .

[Effects of the Invention] As described in detail above, the structure of the present invention has a configuration in which a cylindrical floating body that is expandable and contractible in the axial direction is connected to a throw-in anchor by a mooring line. It can be installed in the sea by transporting it to the installation site offshore of the coastline in the state of being compressed into a small fold, and by extending the floating body at the site and putting it into the sea with the anchor. Installation work is extremely easy and is not affected by water depth, the condition of the seabed, or topography.

Moreover, since it is a submerged type, it does not damage the natural landscape, and it is possible to avoid obstacles to the navigation of ships by setting the installation depth appropriately, and to effectively use the ocean space and prevent ocean erosion. It can be used very effectively for prevention, expansion of recreation area, securing fishing grounds, etc.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing an embodiment of the present invention, and FIG.
FIGS. 3 and 4 are partial plan views showing different arrangement examples of the structure, FIGS. 4 and 5 are front views seen from the axial direction showing further different arrangement examples of the floating body, and FIG. 6 is a different embodiment of the present invention. FIG. 7 is a side view showing a partially broken side view showing an example, FIG. 7 is a side view showing another example of the structure of the floating body, and FIGS. 8 and 9 are a sectional view and a perspective view showing a known example of a breakwater, respectively. 1,21 …… Structure, 2,22,32 …… Floating body, 3,23 …… Mooring line, 4,24 …… Anchor, 6 …… Membrane material, 11 …… Holding means.

Claims (2)

[Claims] 1. A cylindrical floating body, which is formed by a flexible film material so as to be capable of expanding and contracting in the axial direction and provided with a holding means for holding an elongated image body, is connected to a throw-in anchor by a mooring line, A structure for a throw-type floating breakwater, which is configured to be installed at a desired depth in water. 2. A cylindrical floating body formed by a flexible film material so as to be capable of expanding and contracting in the axial direction is connected to individual throw-in anchors by mooring lines at least at both ends,
A structure for a throw-type floating breakwater, which is configured to be installed at a desired depth in water.