JP2000352028A - Wave dissipation type wave force breaking caisson - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wave dissipating type wave force breaking caisson having simple structure and excellent wave dissipating effects. SOLUTION: A front block 3 and a rear dam body 4 are provided on a bottom plate 2, a front inclined surface 7 raising a wave 17 with an up-grade relative to a traveling direction A of the wave 17 is formed in the front surface of the front block 3, and a first wave dissipating passage 5 into which the wave 17 passing over the front block 3 is flown from the front side is formed between the front block 3 and the rear dam body 4. Then, a second wave dissipating passage 6 communicating with the lower part of the first wave dissipating passage 5 from the front side is formed between the bottom plate 2 and the front block 3, and the passage cross-sectional area of the second wave dissipating passage 6 is formed convergently toward the rear.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wavebreak caisson that is installed on a shore or a harbor and has a wave-breaking function.

[0002]

2. Description of the Related Art Conventionally, as a caisson having a wave canceling function, for example, there is a caisson disclosed in JP-A-7-62626. According to this, a large number of cylindrical pillars are installed so as to stand at intervals from each other, and a vortex is generated by waves passing between these numerous cylindrical pillars, and the waves dissipate.
The above type is called a gap type wave-dissipating caisson here.

Another caisson is disclosed in, for example, JP-A-6-212611. According to this, a U-shaped waterway is formed between a plurality of U-shaped embankments exposed from the sea surface. Waves that have entered from one opening of each water channel cannot pass straight through because the water channel is bent in a V shape. As a result, the waves are irregularly reflected between the wall surfaces of the embankment bodies, and the phases of the waves are shifted to produce a phase difference. As a result, the waves cancel each other out to exhibit a wave-eliminating effect. The above type is called a phase difference type wave-dissipating caisson here.

Another caisson is disclosed in, for example, Japanese Patent Application Laid-Open No. 8-232236. According to this, a water play chamber is formed on the open sea side of the caisson main body, and a mass body is movably stored in the water play chamber, and the mass body and the inner wall of the water play chamber are connected via an elastic body.
The mass moves in the water due to the waves incident into the basin. At this time, the mass moves in a direction that impedes the displacement of the seawater in the basin, and generates large friction with the seawater.
Thereby, wave energy is attenuated and waves are attenuated. The above type is referred to herein as a mechanical wave-dissipating caisson.

[0005]

However, the above-mentioned gap type wave-dissipating caisson has a problem in that the caisson becomes large and the cost increases. Further, in the phase difference type wave-dissipating caisson, it is difficult to control the phase of the wave, and it is difficult to generate an effective phase difference in the wave. Therefore, there is a problem that the wave elimination effect is lower than other types.

[0006] Further, the mechanical wave-breaking caisson has a problem that the structure is complicated and the manufacturing cost is high, and that the workability and the maintenance are difficult. SUMMARY OF THE INVENTION An object of the present invention is to provide a wave-damping caisson that can obtain an excellent wave-damping effect with a simple structure, is low in cost, and has good workability.

[0007]

In order to solve the above-mentioned problems, a wave-breaking caisson according to the first aspect of the present invention comprises a first breaker provided between a front block provided on a bottom plate and a rear weir. A wave passage is formed, between the bottom plate and the front block,
A second wave-dissipating passage communicating with a lower portion of the first wave-dissipating passage is formed from the front, and a wave is formed on the front surface of the front block with a rising gradient with respect to a traveling direction of the wave. An inclined surface is formed, and a wave that hits the inclined surface and crosses the front block flows from the front into the first wave-eliminating passage, and the cross-sectional area of the second wave-eliminating passage is closer to the rear. It is formed in a reduced size.

According to this, when a wave hits the front block from the front, the upper part of the wave rises upward due to the inclined surface, and immediately after that, it passes over the front block to the first wave-eliminating passage at a stretch. Crumble. At this time, the pressure of the wave is released and the wave is in a turbulent state, the energy of the wave is attenuated, and a wave-eliminating effect is obtained. At the same time, the lower part of the wave flows into the second wave-eliminating passage from the front. At this time, since the cross-sectional area of the second wave-dissipating passage is reduced toward the rear, the wave that has flowed into the second wave-dissipating passage is gradually narrowed down, and When it reaches the lower part of the first wave-dissipating passage, it is rapidly diffused. As a result, the energy of the wave is attenuated, and a wave-eliminating effect is obtained.

Further, the wave entering the first wave-cancelling passage and the wave entering the second wave-cancelling passage are mixed on the inner side of the two wave-cancelling passages, and the mixed waves are mixed at this time. Since they are disturbed and have different phases, vortices are generated and the energy of the waves is dissipated. As a result, the energy of the wave is attenuated, and a wave-eliminating effect is obtained. In the wave breaking type caisson according to the second aspect of the invention, a seawater exchange circulation part penetrating back and forth is formed at a lower portion of the rear weir.

According to this, when a wave-breaking caisson is installed on a coast or a harbor, etc., seawater flows through a circulation section for seawater exchange due to tide fluctuations. An exchange takes place. As a result, it is possible to prevent the pollutants from staying, and the environment is purified.
In the wavebreaker caisson according to the third aspect of the present invention, an enlarged space portion having an enlarged passage cross-sectional area is formed in a middle portion of the first wavebreaker passage.

[0011] According to this, since the wave that has entered the first wave-cancelling passage is diffused in the enlarged space, the disturbance of the wave is promoted and the wave-damping effect is further improved. In the wave-breaking wavebreak caisson according to the fourth aspect of the present invention, a plurality of flow paths reaching the first wave-breaking passage from the inclined surface are formed in the front block. According to this, a part of the wave hitting the front block from the front flows in the flow path from the inclined surface and passes through the first wave-dissipating passage. At this time, based on the viscosity of the wave (seawater), fluid friction acts between the seawater flowing in the flow passage and the inner surface of the flow passage, and as a result, the energy of the wave is attenuated, and the wave breaking effect is further improved. I do.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1 to 4, reference numeral 1 denotes a wavebreak caisson installed on a coast, a harbor, or the like, and a bottom block 2, a front block 3, and a rear dam 4 that blocks passage of waves 17 to the rear. Is provided. Between the front block 3 and the rear weir 4, a first wave-dissipating passage 5 into which the waves 17 flowing over the front block 3 flow is formed in a vertical direction. Between the bottom plate 2 and the front block 3, a second wave-dissipating passage 6 communicating with the lower part of the first wave-dissipating passage 5 from the front is formed in the horizontal direction.

On the front surface of the front block 3, there is formed a front inclined surface 7 that rises the wave 17 in an upward slope with respect to the traveling direction A of the wave 17. Also, the front inclined surface 7
From the upper end of the front block 3 to the rear surface of the front block 3, a rear inclined surface 8 having a downward slope with respect to the traveling direction A of the wave 17 is formed. At the upper end of the rear weir 4, a top plate 9 protruding horizontally forward is provided. The top plate 9 is located higher than the front block 3 and above the first wave-elimination passage 5.

The lower surface of the front block 3 has waves 17.
The lower inclined surface 10 is formed to be downwardly inclined with respect to the traveling direction A of the vehicle. Further, a wave 1 is provided on the upper surface of the bottom plate 2.
7 has a bottom inclined surface 11 which is inclined upward in the traveling direction A.
Is integrally provided. The second wave-eliminating passage 6 includes the lower inclined surface 10 and the bottom inclined surface 1.
1 and the second cross-sectional area of the second wave-eliminating passage 6 is reduced toward the rear.

The front block 3 and the rear weir body 4 are composed of a plurality of first
And is connected and fixed by the pillars 13 of FIG. The front block 3 and the inclined plate 12 are connected and fixed to each other by a plurality of second pillars 14 provided in the second wave-elimination passage 6 in the vertical direction. As shown in FIG. 5, the front and rear widths of the breakwater caisson 1 (from the front end of the front block 3 to the rear weir 4
W ₀ , front-rear width W ₁ of front block 3, front-rear width W ₂ of top plate 9, front-rear width W ₃ of front inclined surface 7, front-rear width of rear inclined surface 7. W ₄ are set in the following ranges respectively. W ₁ / W ₀ ≒ 1 / 2２〜 / 4 W ₃ / W ₄ ≒ 2-4 W ₂ ≒ W ₀ −W ₁ Also, the inclination angle θ ₁ of the front inclined surface 7 and the rear inclined surface 8
The inclination angle theta _2, the inclination angle theta ₃ of the lower inclined surface 10, the inclination angle theta ₄ of bottom inclined surface 11 is set in the following ranges respectively. θ ₁ = 10 ° to 30 ° θ ₂ = 30 ° to 90 ° θ ₃ = 10 ° to 40 ° θ ₄ = 0 ° to 45 ° With the above θ ₂ = 90 °, the rear inclined surface 8 is eliminated to form a vertical plane. May be. Alternatively, a horizontal plane may be formed by setting θ ₄ = 0 ° and eliminating the bottom inclined surface 11.

The height of the front end vertical surface of the front block 3
h is set as small as possible within a range that does not cause structural problems.
ing. In addition, as shown in FIG.
The distance D in the horizontal direction between the three ₁, Between these pillars 13
The width D of the opening to be formed_TwoIs set in the following range:
Have been. D_Two/ D₁= 0.25 to 0.6 Similarly, between the plurality of second pillars 14 in the left-right direction.
Interval D_Three, The width D of the opening formed between the columns 14_FourIs
It is set in the following range. D_Four/ D_Three≧ 0.5 In addition, as shown in FIG.
The upper end of the h3 is almost equal to the water level H at high tide.
The water level L at low tide is on the front slope 7 of the front block 3.
It is installed so that it is located, and the front block 3 is offshore.
With the rear weir 4 facing the shore
You. In addition, the breakwater caisson 1 has many rocks on the seabed ground.
Are installed on a foundation 18 formed by stacking.

The wave-breaking caisson 1 provides the following wave-eliminating effect. As shown in FIG. 2, when a wave 17 arriving from offshore hits the front block 3 from the front, the upper part of the wave 17
Immediately after the front sloping surface 7 swells upwards, the first sloping surface 8 passes over the front block 3 along the rear sloping surface 8.
Crashes into the wave-eliminating passage 5. At this time, the pressure of the wave 17 is released, and the wave 17 is disturbed.
7 is attenuated, and a wave canceling effect is obtained.

At the same time, the lower part of the wave 17 flows into the second wave-eliminating passage 6 from the front. At this time, since the cross-sectional area of the second wave-dissipating passage 6 is reduced toward the rear, the wave 17 flowing into the second wave-dissipating passage 6 is gradually narrowed down, From the rear end of the first passage 6
Spreads suddenly when it reaches the bottom. As a result, the energy of the wave 17 is attenuated, and a wave canceling effect is obtained.

The wave 17 that has entered the first wave-cancellation passage 5 and the wave 17 that has entered the second wave-cancellation passage 6 are mixed on the inner side of the two wave-cancellation passages 5 and 6. . The space behind the two wave-eliminating passages 5 and 6 where both waves 17 are mixed is referred to as a water-reducing chamber 15, and the waves 17 mixed in the water-reducing chamber 15 are disturbed and their phases are disturbed. Due to the difference, a vortex is generated and the energy of the wave 17 is dissipated. As a result, the energy of the wave 17 is attenuated, and a wave canceling effect is obtained.

Accordingly, the above-mentioned wave-proofing caisson 1 has the advantages that the above-mentioned excellent wave-absorbing effect can be obtained with a simple structure, and that the workability is low and the workability is good. In the above embodiment, the rear inclined surface 8 is formed in the front block 3, but a vertical surface may be formed instead of the inclined surface.

Next, a second embodiment of the present invention will be described. As shown in FIG. 6, at the lower part of the rear weir 4, seawater exchange flow holes 22 (an example of flow parts) penetrating back and forth are formed at a plurality of left and right locations. According to this, due to the tidal fluctuation, the seawater on the back side (the side of the water retarding chamber 15) of the first and second wave-dissipating passages 5 and 6 and the seawater behind the rear weir body 4 flow through the respective flow holes 22. Therefore, seawater is exchanged before and after the breakwater caisson 1. As a result, it is possible to prevent the pollutants from staying in the bay or the like, and to purify the environment in the bay or the like. The shape of each of the flow holes 22 is rectangular as shown in FIG. 6B, but may be circular or elliptical.

The size of each of the flow holes 22 is formed as small as possible within a range that does not hinder the flow of seawater. This is because, by reducing the size of each flow hole 22, exchange of seawater is allowed, but penetration of waves that threaten the conservation of the shoreside sea area is prevented. As a third embodiment, as shown in FIG. 7, when it is difficult to adjust the size of each of the flow holes 22, a small-diameter porous member 23 such as a sponge or gravel is provided in front of each of the flow holes 22.
Is provided.

According to this, the seawater on the inner side of the first and second wave-dissipating passages 5 and 6 (on the side of the water play chamber 15) and the seawater behind the rear weir 4 are formed by the above-mentioned respective flow holes 22 and the porous material. Sea water is exchanged before and after the breakwater caisson 1 because the water flows back and forth through the member 23. As a fourth embodiment, FIG.
As shown in the figure, the hole cross-sectional area of each flow hole 22 is formed to be reduced toward the rear. According to this, when seawater flows from the back side of the first and second wave-dissipating passages 5 and 6 (toward the water-reducing chamber 15) to the rear of the rear weir 4 through the respective circulation holes 22,
Since the seawater is gradually narrowed down in each of the flow holes 22, a contraction occurs, whereby the exchange of the seawater is further promoted.

As a fifth embodiment, as shown in FIG. 9, an enlarged space portion 25 having an enlarged cross-sectional area is formed at two places in the middle of the first wave-dissipating passage 5. I have. The enlarged space portions 25 are provided by forming dents 26 that are respectively depressed forward in upper and lower two portions on the rear surface of the front block 3. According to this, the first
The wave 17 that has entered the wave-cancelling passage 5 is diffused in the enlarged space 25, so that the disturbance of the wave 17 is promoted and the wave-damping effect is further improved.

In the fifth embodiment, the dents 26 are formed at two locations above and below, but may be formed at one location or at three or more locations. As a sixth embodiment, FIG.
As shown in FIG. 11 and FIG. 11, the front block 3 has a plurality of first, left and right first and second flow passages each having one end opened to the front inclined surface 7 and the other end opened to the first wave-dissipating passage 5. Road 30
And a plurality of front and rear and left and right second flow paths 31 each having one end opening to the front inclined surface 7 and the other end merging with the first flow path 30 at the uppermost end.

According to this, a part of the wave 17 that hits the front block 3 from the front flows from the front inclined surface 7 into the first and second flow paths 30 and 31 and the first wave-eliminating wave. Passage 5
Go through. At this time, based on the viscosity of the wave 17 (seawater), the seawater flowing in each of the flow paths 30 and 31 and the flow path 3
Fluid friction acts between the inner and outer surfaces 0, 31 and, as a result, the energy of the wave 17 is attenuated.
Wave 17 entering first wave-dissipating passage 5 through 0, 31
Are in a state of being disturbed due to the occurrence of a phase difference, so that the wave canceling effect is further improved.

In the sixth embodiment, each flow path 3
Although the shapes of 0 and 31 are rectangular, they may be circular or elliptical.

[0028]

As described above, according to the present invention, it is possible to obtain a wave-damping type caisson having a simple structure, an excellent wave-damping effect, a low cost, and a good workability.

[Brief description of the drawings]

FIG. 1 is a perspective view of a breakwater caisson according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the wavebreak caisson viewed from a side.

FIG. 3 is a front view of the breakwater caisson.

FIG. 4 is a partially cutaway plan view of the breakwater caisson.

FIG. 5 is a side view for explaining the relationship between dimensions of each part of the breakwater caisson.

FIG. 6 is a view of a wave-breaking caisson according to a second embodiment of the present invention, (a) is a partially cutaway side view of the wave-breaking caisson, and (b) is an X- line in (a) above. It is an X arrow view.

FIGS. 7A and 7B are diagrams of a breakwater caisson according to a third embodiment of the present invention, wherein FIG. 7A is a partially cutaway side view of the breakwater caisson, and FIG. It is an X arrow view.

8A and 8B are diagrams of a wavebreak caisson according to a fourth embodiment of the present invention, wherein FIG. 8A is a partially cutaway side view of the wavebreak caisson, and FIG. It is an X arrow view.

FIG. 9 is a side view of a breakwater caisson according to a fifth embodiment of the present invention.

FIG. 10 is a cross-sectional view of a wavebreak caisson according to a sixth embodiment of the present invention as viewed from a side.

FIG. 11 is a perspective view of the breakwater caisson.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 wavebreak caisson 2 bottom plate 3 front block 4 rear dam body 5 first wave-dissipating passage 6 second wave-dissipating passage 7 front inclined surface 17 wave 22 flow hole (flow portion) 25 enlarged space portion 30 th Channel 1 A Wave traveling direction

Continued on the front page (72) Inventor Shuichi Nagata 1-7-89 Minami Kohoku, Suminoe-ku, Osaka-shi, Osaka F-term in Hitachi Zosen Corporation 2D018 BA12

Claims (4)

[Claims] A first wave-dissipating passage is formed between a front block provided on a bottom plate and a rear weir body, and the first wave-dissipating passage is provided between the bottom plate and the front block from the front. A second wave-dissipating passage communicating with a lower portion of the wave passage is formed, and an inclined surface which rises the wave as an upslope with respect to the traveling direction of the wave is formed on the front surface of the front block, The first wave-dissipating passage is formed such that a wave that hits the inclined surface from the front and crosses the front block flows from the front, and the cross-sectional area of the second wave-dissipating passage is reduced toward the rear. A wave breaking type caisson characterized by the following. 2. The wavebreaking caisson according to claim 1, wherein a lower part of the rear weir body is formed with a circulation part for seawater exchange penetrating back and forth. 3. The wave-breaking protection device according to claim 1, wherein an enlarged space portion having an enlarged cross-sectional area is formed in a middle portion of the first wave-breaking passage. Wave caisson. 4. The wave absorber according to claim 1, wherein a plurality of flow paths reaching the first wave-eliminating passage from the inclined surface are formed in the front block. Type breakwater caisson.