JP4068748B2 - Installation method of wave absorber - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of installing a wave-dissipating body that is installed in front of a breakwater that restricts waves from the open sea or creates a calm sea area in a shell or the like of a harbor and attenuates the energy of the waves.
[0002]
[Prior art]
The most common breakwaters built in harbors and the like are made of concrete structures such as caisson. That is, as schematically shown in FIG. 4, such a caisson type breakwater is obtained by installing a breakwater main body 101 made of caisson or the like on a rubble mound 102 laid on the seabed ground G, and is orthogonal to the illustrated cross section. Since it extends in the direction and hardly transmits the waves W from the open sea A, it is extremely effective in creating a calm sea area B.
[0003]
In the case where the breakwater main body 101 extends so as to be orthogonal to the traveling direction of the waves W approaching from the open sea, the impact due to the wave collision is large. In addition, since waves are reflected on the front surface of the breakwater main body 101, it is known that when the reflectance is large, the apparent wave height increases due to interference between the reflected wave and the incident wave. Therefore, in such a case, the wave breaker 103 is installed by stacking a large number of tetrapods (registered trademark) on the outer sea side of the breakwater main body 101. In other words, the wave breaker 103 attenuates wave energy by friction loss and disturbance caused when the waves W approaching from the open sea A pass through a gap formed in a maze formed between the tetrapods (registered trademark). , To reduce impact and reduce reflected waves.
[0004]
[Problems to be solved by the invention]
However, the following problems are pointed out in the above prior art. First, if the wave-dissipating work 103 is installed by stacking wave-dissipating blocks such as Tetrapod (registered trademark) , it becomes difficult to berth the ship to the breakwater main body 101. Become. In addition, since many tetrapods (registered trademark) with special shapes are required, there is a problem that the construction cost is increased. Therefore, in such a case, a hollow wave absorber (not shown) that attenuates wave energy by providing a large number of slits may be installed on the front surface of the breakwater main body 101 made of caisson. In order to newly install a wave body, it is necessary to add a rubble mound 102 on the seabed ground G on the front side of the breakwater main body 101, and there is a problem that it is dangerous because there are many underwater operations during installation.
[0005]
The present invention has been made under the circumstances as described above, and the technical problem is that it has excellent wave-dissipating performance regardless of numerous wave-dissipating blocks such as Tetrapod (registered trademark). An object of the present invention is to provide a wave-dissipating body that can be exhibited, and to make it possible to install the wave-dissipating body without underwater work.
[0006]
[Means for Solving the Problems]
As a means for effectively solving the technical problem described above, the method for installing a wave breaker according to the present invention includes a plurality of supporting materials partially extending to the open sea side at predetermined intervals in the extension direction on the upper surface of an existing breakwater. A wave-dissipating body, which is fixed in a protruding state and is provided with a required number of support material insertion portions formed substantially horizontally at a predetermined interval in the extension direction of the breakwater, is arranged in a state where it floats from the seabed in front of the existing breakwater At the same time, the support member insertion portion of the wave-dissipating body is inserted into and fixed to the projecting portion of the support material toward the outside sea. The “front surface” here refers to a surface facing the open sea side, and the “outer sea” refers to a sea area where waves to be wave-dissipated are gathered.
[0008]
The wave breaker is formed by inserting and fixing a required number of support material insertion portions formed substantially horizontally on the upper portion at predetermined intervals in the extension direction of the breakwater into a support material fixed on the upper surface of the existing breakwater. Because it is installed in the state where it floated from the sea floor in front of the sea, there is no need for underwater work at the time of installation, and it is necessary to add a rubble mound for the wave-dissipating body on the sea floor ground on the front side of the existing breakwater Absent. The support member can be fixed to the upper surface of the existing breakwater by a normal fixing means such as an anchor, but the fixing strength can be supplemented by a method of placing a weight as in the embodiment described later.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a state in which a wave breaker according to an embodiment of the present invention is installed on an existing breakwater, wherein (a) is a partial plan view, and (b) is a bb ′ cross section in (a). FIG. In FIG. 1, reference numeral 1 is an existing breakwater constructed in a relatively calm sea area in the port, that is, a rubble mound 11 laid by laying a large number of rocks, stone blocks, etc. on the seabed G. The caisson 12 made of concrete is installed in a state where the upper part is exposed from the sea surface, and extends in a direction orthogonal to the illustrated cross section.
[0010]
The breakwater 1 is to create a calming sea area B by isolating the inside of the harbor from the open sea A by the caisson 12 which is the breakwater main body and blocking the wave W. The caisson 12 is built in a dock not shown in the drawing in a length divided into several in the longitudinal direction of the wave-breaking breakwater, and after being towed by a crane ship or the like, is laid on the rubble mound 11 It is.
[0011]
The wave-dissipating body 2 is installed on the upper part of the front surface 12a facing the outer sea A side of the caisson 12. The wave-dissipating body 2 includes three support material insertion portions 21 that penetrate substantially horizontally in the front-rear direction in the upper part and are opened at predetermined intervals in the longitudinal direction. By being inserted into the support material 3 fixed three by three, the bottom surface is supported in a state where the bottom surface is floated from the top surface of the rubble mound 11 at a height that is always immersed in seawater regardless of fluctuations in the water level due to tides. .
[0012]
As shown in the cross-sectional perspective view of FIG. 2, the wave-dissipating body 2 is a concrete product that has a rectangular parallelepiped shape as a whole, and is a recreational water that is open to the outside through a large number of slit-like openings 22 in the front surface 2a. A chamber 23 is formed, and a labyrinth-like cross-sectional shape is formed by a large number of beam portions 24 in the water reserving chamber 23. The number, shape, and size of the slit-shaped openings 22 and beam portions 24 are appropriately set in consideration of strength, attenuation performance against waves, and the like.
[0013]
The support material 3 supporting the wave-dissipating body 2 is made of, for example, a steel material whose surface is rust-proofed, and is fixed to the upper surface of the caisson 12 via a plurality of anchors 31. Each support member 3 is connected to each other through a coupling member 32 made of a number of rust-proof steel bars or steel bars, and a weight 33 is loaded on the coupling member 32 as necessary. The fixing force by the anchor 31 can be supplemented.
[0014]
According to the above configuration, the waves W coming from offshore of the open sea A collide with the front surface 2a of the wave-dissipating body 2. The front surface 2a is provided with a large number of slit-like openings 22 that allow the passage of the waves W. Therefore, the collision area is small. In addition, the waves W entering and exiting the water chamber 23 through the slit-like opening 22 are subjected to friction loss and disturbance due to contact with a large number of beam portions 24 in the process, and a part of wave energy is consumed. Therefore, the impact on the caisson 12 due to the collision of waves is remarkably mitigated.
[0015]
In addition, the reflected wave generated by the collision with the back plate portion 25 after passing through the water reserving chamber 23 is attenuated in the process of passing through the water reserving chamber 23 again. For this reason, the reflected wave is also significantly attenuated, and an increase in wave height due to interference with the incident wave W is effectively suppressed.
[0016]
Hereinafter, the installation method of the said wave-dissipating body 2 is demonstrated in order of a process, referring FIG. First, Fig.3 (a) shows the process of fixing the support material 3 to the upper surface 12b of the caisson 12 which is an existing breakwater main body. Each support member 3 has an interval corresponding to the opening interval of each support member insertion portion 21 of the wave breaker 2 with respect to the extension direction of the breakwater, and a length L corresponding to the width of the wave breaker 2 in the front-rear direction. It arrange | positions in the state which protruded to the open sea A side, and is fixed by the some anchor 31 driven into the upper surface 12b of the said caisson 12, respectively.
[0017]
Further, when it is determined that the pulling resistance of the anchor 31 alone cannot sufficiently counter the moment applied to the support member 3 with the upper end portion of the caisson 12 as the fulcrum P due to the weight of the wave-dissipating body 2, FIG. As shown in FIG. 2, the adjacent support members 3 are connected to each other through the connecting member 32, and the weight 33 is loaded on the connecting member 32, thereby pressing the support member 3 against the upper surface 12 a of the caisson 12. To.
[0018]
Next, FIG.3 (c) shows the attachment process of the wave-dissipating body 2. FIG. That is, in this step, the wave-dissipating body 2 is hung at a predetermined position indicated by a one-dot chain line in the figure on the front surface of the caisson 12 by the crane 4 installed on the caisson 12 or on the sea. And in the movement process, each support material insertion part 21 of the said wave-dissipating body 2 is inserted in the protrusion part to the open sea A side of the support material 3. As shown in FIG. When the wave-dissipating body 2 is supported by the support material 3 by being completely inserted, the sling rope 4a is removed from the wave-dissipating body 2, and a grout (not shown) is formed in the gap between the support material 3 and the support material insertion portion 21. (Omitted) etc., so that both are securely fixed. In addition, since all of these series of operations can be performed from the top of the caisson 12, no underwater operation is required.
[0019]
Next, in this state, there is a step on the upper surface of the caisson 12 due to the support material 3 and the weight 33. Therefore, when it is possible to pass on the caisson 12, as shown in FIG. The raised pavement 13 is applied so that the weight 33 is filled and the upper surface becomes flat. Since the raised pavement 13 has a function of fixing the support material 3 on the caisson 12, the installation of the weight 33 may be omitted and the raised pavement 13 may be fixed.
[0020]
In the above-described embodiment, the breakwater main body is made of the caisson 12, but it is naturally applicable to breakwaters made of other concrete structures. Further, the wave-dissipating body 2 is not particularly limited to the shape shown in the figure, and various types such as a slit shape extending vertically or a lattice shape are conceivable.
[0021]
【The invention's effect】
According to the present invention, the wave-dissipating body does not use a large number of wave-dissipating blocks such as Tetrapod (registered trademark) , but the front upper part of the existing breakwater by the support material inserted into the support material insertion part formed in the upper part. Therefore, installation work can be performed safely without requiring underwater work. Moreover, since the lower end is installed in a state of floating from the seabed, it is not necessary to add a rubble mound or the like, and the construction period and cost can be reduced.
[Brief description of the drawings]
FIG. 1 shows a state in which a wave breaker according to an embodiment of the present invention is installed on an existing breakwater, wherein (a) is a partial plan view, and (b) is a bb ′ cross section in (a). FIG.
FIG. 2 is a cross-sectional perspective view showing a single wave-dissipating body according to the embodiment.
FIG. 3 is an explanatory view showing a method for installing a wave absorber according to the present invention in the order of steps.
FIG. 4 is a cross-sectional view showing a wave breaker in the prior art together with a breakwater.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Breakwater 12 Caisson 13 Raised pavement 2 Wave breaker 21 Support material insertion part 22 Slit-like opening part 23 Reservoir room 23
3 Support material 31 Anchor A Outer sea B Quiet sea area

Claims (1)

On the upper surface of the existing breakwater, a plurality of support materials are fixed at predetermined intervals in the extending direction, with a part protruding to the open sea side,
Disposing a wave breaker having a required number of support material insertion portions formed substantially horizontally at a predetermined interval in the extension direction of the breakwater, in a state where it floats from the sea floor to the front of the existing breakwater,
An installation method for a wave-dissipating body, characterized in that the support material insertion portion of the wave-dissipating body is inserted and fixed into a projecting portion of the support material toward the outside sea.

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