JP2585921B2 - Waveguide-type squirting wavebreak structure and wavebreak structure using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveguide type squirting wavebreak structure having a wavebreak function and capable of enhancing hydrophilicity at a waterfront, and a wavebreak structure using the same.

[0002]

2. Description of the Related Art Breakwaters at seawalls or offshores are widely known by structures called caisson. There are various types of caisson depending on the shape, function, and the like. For example, types such as an upper slope caisson embankment, a curved slit caisson embankment, a vertical slit caisson embankment, or a perforated caisson embankment are known.

Further, Japanese Patent Application Laid-Open No. HEI 2-112516 discloses a wavebreak structure having a wave energy absorbing device for converting wave energy into air energy by an air piston and absorbing it.

[0004] Furthermore, many proposals have been made to enable the distribution of seawater in water areas inside and outside the breakwater and to purify the bay inside the breakwater. One of them is the actual Kaihei 3-65721
There is. In this method, a pipe was buried in a layer of gravel between the walls, one end of the pipe was trumpet-shaped, penetrated through the open sea side of the wall, and exposed to seawater, and the other end was exposed to the open air above. Things. The seawater from the open sea is blown up through a pipe and then guided to the gravel layer, purified while passing through the gravel layer, and guided to the inland sea side.

[0005]

All the conventional caissons are designed mainly for the purpose of preventing or breaking waves. However, in the recent waterfront development, one of the main purposes is to bring a person back to the waterside, and it has been demanded that the caisson, which is the above-mentioned wave-proof structure, be made more hydrophilic. However, since the conventional caisson is mainly designed for breaking or breaking waves, the design to increase the hydrophilicity is only to change the design, even if the promenade is arranged on the waterside, An attractive performance that could bring humans back to the water could never be realized.

[0006] Regarding this kind of production,
According to 65721, the seawater launched into the pipe blows up, realizing a kind of natural fountain and enhancing the landscape. However, in the technology disclosed in the above publication,
Since the trumpet-shaped opening, which is the intake of the fountain, is always submerged, it is unlikely that a sufficient effect to enhance the hydrophilicity can be expected.

Therefore, an object of the present invention is to pay attention to squirting or fountain as a staging effect at the waterside, and to blow up seawater throughout the year by effectively using surplus wave energy in the water area to produce water. It is an object of the present invention to provide a waveguide-type squirting wave-breaking structure having high wave-proofing effect while achieving high performance and light weight, and a wave-breaking structure using the same.

[0008]

According to the present invention, there is provided a waveguide-type squirting wavebreak structure according to the present invention, which communicates from a first opening opening on a wave receiving surface to a second opening opening on a top surface, and the first opening. From the opening
The first opening has a communication hole including a tapered region in which the cross-sectional area of the hole becomes smaller continuously toward the second opening up to the vicinity of the second opening, and the lower edge of the first opening has an average water level at low tide. And the upper edge of the opening is set at a position higher than the average water level at high tide.

The wave-proof structure may have a plurality of the communication holes each having the first opening at a different height of the wave receiving surface. In this case, the uppermost first opening is provided. Is set higher than the average water level at high tide, and the lower edge of the first opening at the lowest position is set lower than the average water level at low tide.

[0010] According to the present invention, there is provided a wave-proof structure.
In the foundation work area at the bottom of the water area where the breakwater structure is installed, the slope is such that the water depth becomes deeper as going offshore, and before reaching the wave receiving surface of the structure. And a mound for breaking waves.

The mound is preferably formed as a wave collecting mound that spreads radially outward from the wave receiving surface of the wave-breaking structure.

[0012]

When a wave arrives at the wave receiving surface of the wave-breaking structure, the wave receiving surface performs a wave-preventing action, and a part of the waves is launched from the first opening. The launched wave is guided along the communication hole and reaches the second opening that is open on the top surface of the wave-breaking structure. At this time, since the communication hole is formed so that the hole cross-sectional area becomes smaller toward the second opening, the water guided through the communication hole is accelerated, and furthermore, is guided upward. The water is blown upward from the second opening, and it produces an effect as a squirt or a fountain. Blowing up seawater in this way can consume a part of the wave energy as squirting or fountain, so that the waves can be extinguished, and can withstand sufficiently without increasing the strength of the breakwater structure. The obtained wavebreaking structure can be realized. Further, since the communication hole is formed, the weight of the wave-proof structure can be reduced. In addition, the first opening has an opening portion above the water surface rather than being completely submerged, so that wave energy can be sufficiently utilized for blowing up seawater. Moreover, despite the ebb and flow
In order to constantly blow up the fountain throughout the day and throughout the year, it is essential to define the opening position of the first opening as in the present invention.

In order to enhance the fountain effect, it is preferable to make the cross section circular rather than the square cross section in that the water can be smoothly guided. Further, the circular cross section is continuously reduced. Thus, it is possible to reduce the energy loss during the movement of the communication hole and contribute to the effective blowing of the fountain.

The first of such a waveguide type squirting breakwater structure is
When guiding the wave to the opening, it is preferable to break the wave in front of the breakwater structure, and for this purpose, it is preferable to form a mound of a predetermined length having a gradient in which the water depth becomes deeper as going offshore. By forming the mounds radially, it is possible to collect waves in a range wider than the opening width of the first opening of the wavebreaking structure, and to secure a higher fountain effect.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment to which the present invention is applied will be described.
This will be specifically described with reference to the drawings.

FIG. 1 shows a caisson 10 which is an example of a wavebreak structure according to the present embodiment. This caisson 10
It has a rectangular parallelepiped shape made of concrete, and its central hollow is filled with sand and the like. The caisson 10 has, for example, a vertical wave receiving surface 12 facing the offshore side and a horizontal top surface 14, for example.
A second opening 18 is formed in 4, and both openings 16, 18 communicate with each other through a communication hole 20. In addition, the wave receiving surface 12 may be arranged to be inclined at an obtuse angle with respect to the horizontal plane.

In this embodiment, as shown in FIGS. 2A and 2B, a plurality of, for example, three first openings 16 are formed in the wave receiving surface 12 of the caisson 10 constituting one block, and the top surface is formed. Similarly, three second openings 18 are formed in 14. The communication hole 20 that communicates the first and second openings 16 and 18 has a trumpet shape, and is formed such that the circular hole cross-sectional area becomes smaller continuously from the first opening 16 toward the second opening 18. I have. In order to form such a communication hole 20, the lower edge 22 of the communication hole 20 shown on the cross section in FIG. 1 is formed, for example, with a constant curvature and an arc length of 1/4. On the other hand, the upper edge 24 of the communication hole 20 has a linear portion 24a having a predetermined length from the first opening 16 side, and the linear portion 24a and the second opening 1
8 is formed as a curved portion 24b having a quarter arc length.

Further, on the top surface 14 of the caisson 10, a blow-out path extending block 2 for guiding the blow-up vertically upward is provided.
6 is provided integrally with or separately from the caisson 10. In addition, the squirting passage opening to the top surface 14 is not limited to the one extending vertically upward, and may be preferably inclined backward at an obtuse angle with respect to the horizontal plane. Further, on the top surface 14 and the wave receiving surface 1
On the edge of the second side, a wave returning block 28 is provided with a caisson 10.
Is provided integrally or separately.

The height and size of the first opening 16 are as shown in FIGS. 2A and 2B. First, the lower edge 16a of the first opening 16 is set at a position lower than the average water level height H ₁ of the low tide. On the other hand, the upper edge 16b of the first opening 16 is set at a position higher than the average water level height H ₂ of the high tide. In other words, the height of the center of the first opening 16 is set to be approximately the average water surface position, and
It is preferable to set the diameter of No. 6 to a length equal to or greater than the ebb and flow. As described above, the diameter of the first opening 16 that can cover the ebb and flow of the ebb and tide is, for example, 150 cm or less in the maximum diameter, and preferably in the range of 130 to 150 cm when installed facing the Pacific Ocean. In the case of the Japan Sea side where the tide level changes less than in the Pacific Ocean, it can be used for installation in the Pacific Ocean.However, in the case of a dedicated type installed facing the Sea of Japan, the maximum diameter is 50 cm or less, preferably 40 to 50 cm. Is enough.

Next, the operation of the caisson 10 will be described.

When the wave pressure from the offshore side repeatedly acts on the wave receiving surface 12 of the caisson 10, the wave is received by the wave receiving surface 12, and it is possible to prevent the wave from entering the shore.

At this time, seawater infiltrates into the first opening 16 opened in the wave receiving surface 12 due to the pressure of the wave. This seawater moves along the trumpet-shaped communication hole 20 and is guided toward the second opening 18. At this time, since the cross-sectional shape of the communication hole 20 is a shape in which the cross-sectional area decreases continuously from the first opening 16 to the second opening 18, the seawater guided along the communication hole 20 is accelerated. Will be.
Further, since the communication hole 20 guides the seawater that has intruded in the horizontal direction from the first opening 16 gradually upward and vertically, the seawater is blown up like a squirt or a fountain from the second opening 18. It will blow out. In particular, in this embodiment, since the curved portion 24b of the lower edge 22 and the upper edge 24 of the communication hole 20 is used as a 1/4 arc portion, the seawater blown out from the second opening 18 is vertically tangential to the arc. Is blown up in a form to which centrifugal force is applied. Therefore, it becomes possible to realize a squirting or fountain considerably higher than the second opening 18.

In particular, since the first opening 16 is opened at a position where it is not always submerged irrespective of the time of the ebb and flow, seawater near the water surface having high wave energy can be guided to the first opening 16.
Seawater can be blown up efficiently and year round.

The fountain utilizing the natural wave force can exert the following effects. One of them is
The purpose is to increase the hydrophilicity in the waterfront. That is, the squirting or the fountain from the second opening 18 using the wave force is repeatedly realized at substantially the cycle of the wave throughout the year, and further, the blowing up of a considerable height is realized by the above-described operation. In the winter, it can bring out coolness like a fountain in a park, and in winter, it can bring out the intensity of rough seas, and can efficiently increase the hydrophilicity at the waterside. In order to secure such a production effect at night, ancillary facilities such as lighting were installed in Caisson 1.
It may be provided at 0.

The other is that the wave received from the first opening 16 is converted into the second opening 18 by the above-mentioned fountain effect.
By discharging more, the wave energy is consumed as a fountain. This leads to the effect of reducing the mechanical strength of the caisson 10 that can withstand the wave when designing the wave-proof structure of the caisson 10. In addition, by consuming wave energy as a squirt or a fountain, a wave-dissipating function can also be achieved.

By forming the blow-off channel extending block 26 on the top surface 14 of the caisson 10, it is possible to extend and secure the passage of the squirting water or the fountain to be blown vertically upward. And a higher fountain height can be secured. In addition, by installing the wave returning block 28, it is possible to reduce the influence of the overtopping wave acting on the fountain blown up from the second opening 18.

The upwardly curved communication hole 20 not only contributes to the blowing action of seawater, but also can be used as a force for stably setting the caisson 10 vertically downward by the component force of the water pressure acting on the curved surface.

FIG. 3 shows a plurality of first openings 36 at different positions in the height direction of the wave receiving surface 32 of the caisson 30.
The structure in which a and 36b are formed is shown. The solid line in the figure shows the lower first opening 36b formed immediately below the upper first opening 36a. In this case, the two second openings 38a and 38b opening in the top surface 34 are offshore and shoreside. It is open at the position shifted. Instead of this embodiment, the lower first
If the opening 36b is formed at a position shifted from the upper first opening 36a in the front and back directions in the drawing, the two second openings 38a, 3
8b can also be opened on the same line at an equal distance from the wave receiving surface 32 (see the dashed line in FIG. 3). In FIG. 3, the communication holes 40a, 40b communicating the respective openings have a trumpet shape such that the cross-sectional area is continuously reduced toward the second openings 38a, 38b similarly to the communication hole 20 shown in FIG. I have.

As described above, by providing the two first openings 36a and 36b at different positions in the height direction of the wave receiving surface 32, the following two effects can be obtained. One is that two types of squirting or fountains having different heights can be realized in the second openings 38a and 38b. That is, since the seawater entering from the upper first opening 36a has larger wave energy, the height of the seawater blown up from the second opening 38a can be secured higher than the height blown up from the other second opening 38b. As a result, it is possible to further enhance the effect of the squirting or the fountain. Another is that it can correspond to the tide level of seawater.
In other words, when the tide level becomes low, the amount of seawater that intrudes into the upper first opening 36a decreases. At this time, the seawater that intrudes through the lower first opening 36b is used, and the corresponding second opening 38b is used. A squirt or fountain of a predetermined height can be realized.

Here, when a plurality of types of communication holes having different heights are provided, it is necessary to blow up a fountain using at least one communication hole at any time of the ebb and flow, so that the first opening at the uppermost position is required. The upper end is higher than the water level H ₂ at high tide, and
It is necessary to lower the water surface height H ₁ of the low tide the lower edge of the first opening at the lowermost point. In consideration of this, as shown in FIG. 3, two first parts are located above and below the same location in the caisson width direction.
It is even better to have the structure shown in FIG. 8 rather than forming an opening. This shows a case in which, for example, two types of communication holes 40a and 40b having different height positions are arranged so that the positions in the caisson width direction are also shifted. In this way, cover the communication holes 40a, the first opening 36a of 40b, 2 Tsude of 36b, the average water surface height position of H ₂ average water level height H ₁ and a high tide during low tide shown in FIG Easier to do. Thus, a structure that can easily cope with the tide level described above can be realized.

Next, a wavebreak structure using the caisson 10 or the caisson 30 in the above embodiment will be described with reference to FIGS.

In the breakwater structure shown in FIG. 4, a caisson 10 or 30 is disposed at the tip of a central jetty 50 extending from the shore to the offshore, and breakwaters 52 are provided on both sides thereof. The central jetty 50 and the breakwater 52 can be configured as natural roads using relatively large natural stones as shown in FIG. The surrounding area including the embankment and the installation area of the caisson 10 or 30 becomes the foundation work area 54.

The feature of this wavebreak structure is that a mound 60 having a predetermined length and a predetermined gradient is formed from the front surface of the caisson 10 or 30 to the offshore. The mound 60 has, for example, the same width as the width of the caisson 10 (30), and the area of several meters adjacent to the caisson 10 (30) is a horizontal area where the covering block 62 is arranged as shown in FIG. I have. The mound 60 is formed as an inclined portion 64 inclined toward the offshore with a substantially constant gradient with the covering block 62 at the maximum height.

Assuming that the length of the inclined portion 64 is L and the maximum height is H, the gradient is expressed as H / L. less than,
The length L and the slope H / L of the inclined portion 64 will be considered while explaining the function of the mound 60.

The reason for providing the mound 60 is to break a wave that is rushing in front of the caisson 10 (30). That is, when only the amplitude of the wave that is not broken reaches the wave receiving surface 12 or 32, an effective fountain is not blown up from the second opening. If the mound 60 inclined in front of the caisson 10 (30) is provided, the water depth becomes shallower as the wave approaches the caisson 10 (30), the wave height gradually increases, and finally breaking waves occur. Providing the inclined portion 64 of the mound 60 with an excessively long length is not economical because the foundation work area is enlarged, and breaks waves far in front of the caisson 10 (30). Conversely, if the length of the inclined portion 64 is excessively short, wave breaking cannot be realized before reaching the caisson 10 (30).

In the case of this embodiment, the simulation was performed under the condition that the wave period was 5.5 seconds, the wavelength was 40 m, and the wave height of the offshore wave was 1 m or less. The L was 20 m, the H / L was 1/10, and the caisson 10 Wave breaking can be performed immediately before (30),
It was found that the fountain could be blown up using wave energy effectively.

From the above points, the present inventors have considered the length L of the inclined portion 64, and as a result, preferably, 15m ≦ L ≦
It is preferable to set 50 m, more preferably 20 m ≦ L ≦ 30 m. If the length is shorter than the above range, the wave height does not grow so as to crush just before the caisson. If the length is longer than the above range, the mound installation cost increases and it is not economical.

Next, considering the slope H / L of the mound 60, from the viewpoint of setting the distance L relatively short for economic reasons, 1/30 ≦ H / L ≦ 1/8, especially 1/30 ≦ H / L ≦ 1/8.
A value set to around 10 is desirable.

FIG. 5 shows that the wave energy is effectively collected in the caisson 10 (30) having a certain width, and the blowing efficiency of the fountain is kept high.

The breakwater structure shown in the figure is composed of a T-shaped jetty 70 composed of a central jetty 72 and a jetty 74, and the caisson 10 is placed almost flush with the jetty 74 and in front of the central jetty 72. This is a structure in which (30) is provided. A wave collecting mound 76 is formed offshore from the caisson 10 (30) by foundation work. When the caisson 10 (30) is located at the center, the collecting mound 76 has a substantially semi-circular or semi-elliptical area formed with an inclined surface in a substantially radial direction, and the inclined surface is similar to that of FIG. Then, the water depth increases as the distance from the caisson 10 increases.

According to such a wave collecting mound 76, since the wave travels in the direction of decreasing water depth, the caisson 1
Waves are gathered almost in the front area of 0 (30), and the caisson 10 is efficiently used by utilizing the wave energy of the collected waves.
The fountain can be blown up through the communication hole 20 or 40a, 40b provided in (30).

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention.

In each of the above embodiments, the caisson 10 (30)
Is configured as a so-called offshore type which is disposed at the tip end side of the central jetty 50 or 70, but may be configured as a seawall type. Furthermore, in both types of offshore and revetment types, caisson 10
(30) may be continuously provided in the lateral direction over a predetermined length. When the caisson 10 (30) is configured as a detached type, the caisson 10 (30) may be configured to float on the sea surface, and may be floated at a predetermined position using a wire, a weight, or the like.

FIGS. 6 and 7 show a modification in which the caisson 10 is used for another purpose.

The structure shown in FIG. 6 shows a structure in which a guide block 80 having an L-shaped cross section which is opened only on the wave receiving surface 12 side is provided on the top surface 14 of the caisson 10. According to this structure, the seawater that has entered through the first opening 16 blows out from the second opening 18 through the communication hole 20, is further guided by the guide block 80, and is drained offshore. This structure can be used as a wave-dissipating structure.
The wave energy can be consumed and the wave extinction function can be realized by guiding the vehicle through the wave.

The structure shown in FIG. 7 has a guide block 8 having an L-shaped cross section and opening on the shore side on the top surface 14 of the caisson 10.
2, and a seawater exchange hole 84 that penetrates from the shore to the offshore in the lower area of the caisson 10. In this case, the seawater that has entered through the first opening 16 is guided to the shore through the communication hole 20 and the guide block 82, but the seawater that has increased on the shore is replaced by the seawater exchange hole 8.
It will be returned offshore via 4. Therefore, if this structure is installed as a detached type, it is possible to have not only a wave-dissipating function as in the case of FIG. 6 but also a seawater exchange function on the offshore shore side.

[0047]

As described above, according to the present invention,
Through the year, it is possible to realize a structure that can effectively blow up seawater using wave energy, which is a natural force, enhance hydrophilicity at the waterfront, and can be used as a wavebreak structure.

Further, by forming a mound in front of the breakwater structure, it is possible to break waves before reaching the breakwater structure, and to more efficiently utilize wave energy as seawater blowing power. Become.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of one embodiment of a structure according to the present invention.

2A is a plan view of the structure shown in FIG. 1, and FIG. 2B is a front view thereof.

FIG. 3 is a schematic cross-sectional view showing a modification of the structure in which two first openings are formed at different positions in the height direction.

FIG. 4 is a plan view of one embodiment of a wavebreak structure according to the present invention.

FIG. 5 is a plan view of an embodiment of a wavebreak structure having a wave collecting mound.

FIG. 6 is a schematic cross-sectional view of a wave-breaking structure configured by adding a guide block to the structure according to the present invention.

FIG. 7 is a schematic cross-sectional view of a wavebreak structure having a seawater exchange function constituted by providing a guide block and a seawater exchange hole in the structure according to the present invention.

FIG. 8 is a schematic explanatory view of a modification having two types of communication holes in which the height position and the lateral position of the first opening are both different.

[Explanation of symbols]

 10, 30 Wave-proofing structure (caisson) 12, 32 Wave receiving surface 14, 34 Top surface 16, 36a, 36b First opening 18, 38a, 38b Second opening 20, 40a, 40b Communication hole 60 Mound 62 Covering block 64 Inclined part 76 Wave collecting mound

Continuation of the front page (72) Inventor Toshifumi Sato 1-7-1 Kyobashi, Chuo-ku, Tokyo Inside Toda Construction Co., Ltd. (72) Inventor Keiji Nishiyama 1-7-1 Kyobashi, Chuo-ku, Tokyo Toda Construction Co., Ltd. (56) References JP-A-49-8044 (JP, A) JP-A-49-6746 (JP, A) JP-A-3-68496 (JP, A) JP-A-3-65721 (JP, U)

Claims (4)

(57) [Claims] A first opening that opens on the wave receiving surface and a second opening that opens on a top surface that projects above the water surface,
The second opening extends from the first opening to the vicinity of the second opening .
Hole cross-sectional area toward the opening in succession have a communication hole comprising a tapered portion which becomes smaller, the first opening is lower than the average level at the lower edge of the opening is low tide, the upper edge of the opening Is set at a position higher than the average water level at high tide. 2. A first opening opening on the wave receiving surface communicates with a second opening opening on the top surface projecting above the water surface,
The second opening extends from the first opening to the vicinity of the second opening .
Includes a plurality of communication holes each having the first opening at a different height position of the wave receiving surface, each including a tapered portion where the hole cross-sectional area becomes continuously smaller toward the opening, and A waveguide-type squirting breakwater, wherein the upper edge of one opening is set higher than the average water level at high tide, and the lower edge of the first opening at the lowest position is set lower than the average water level at low tide. Structure. 3. The structure of claim 1 or 2, wherein the structure has a slope in which the water depth is deeper toward the offshore in a foundation work area at the bottom of the body of water where the structure is installed. A mound for breaking waves before reaching the wave receiving surface of the body. 4. The wavebreak structure according to claim 3, wherein the mound is formed substantially radially outward from the wave receiving surface of the structure.