JPH10237842A - Wave suppressing structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wave suppressing structure which not only has a sufficient wave-suppressing hydraulic function irrespective of wave direction but also is desirable as the environment creating type. SOLUTION: A wave suppressing structure comprises one or two or more wave suppressing units 3 installed on a foundation bed 1 on the sea. A wave suppressing wall 5 constituting the outer shape of the wave suppressing unit 3 is formed into an arc shape pointed in the directions S of waves coming from all directions. A hollow chamber 9 is provided inside the unit 3, and an opening 11 provided in the part of the wave suppressing wall 5 below design high tide level-(H.W.L) and opposite to the main wave direction S communicates the hollow chamber 9 to the sea outside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wave-dissipating structure mainly installed in a coastal area facing the open sea and used as a breakwater or a headland.

[0002]

2. Description of the Related Art Conventionally, as a wave-dissipating structure, an inclined dike,
Various types such as wave-breaking block-covered embankments, floating breakwaters, and permeable wall embankments have been proposed and provided for customers. Among these wave-dissipating structures, a slope-dyke in which a wave-dissipating block, stones, and the like are stacked in a trapezoidal shape mainly attenuates wave energy by breaking waves on a slope to extinguish waves.

In addition, a large number of wave-dissipating blocks are installed in front of an upright embankment (or a mixed embankment) installed in the sea, and each wave-breaking block attenuates wave energy and erects the embankment body. The part (upright surface) suppresses the transmission of waves, and as a wave-eliminating block, a multi-leg block such as a so-called tetrapod (registered trademark) quadruped block or hexapod block, a hollow triangular block, Hollow scales are used.

On the other hand, a floating breakwater in which a floating body such as a raft, a catamaran, a flexible body or the like is moored to a support, prevents waves from being generated in a backwater area by reflecting waves by the floating body. is there. Further, the water-permeable wall embankment formed by providing a large number of slits and through-holes in the wave-absorbing wall attenuates energy by scattering water particles when waves pass through the water-permeable wall.

[0005]

All of the above-mentioned wave-dissipating structures are intended for wave-dissipation and erosion prevention in the coastal sea area facing the open sea, but they have flat surfaces including upright surfaces and the like. In many places, the wave energy attenuating effect (wave-dissipating effect) may be reduced in places slightly deviated or turned around from the wave direction (wave traveling direction). In addition, it is difficult to adapt to the so-called MMZ (Marine Multi Zone) concept of creating and using a multipurpose space in coastal waters proposed by the Ministry of Construction, and it is a structure with a friendly image that protects the coastal environment and is gentle From the point of view, there are still points to be improved.

[0006]

Therefore, as a means for solving the above-mentioned problems of the prior art, the wave-breaking structure according to the first aspect of the present invention comprises one or more of The wave direction S of the wave which attacks the wave-absorbing wall 5 constituting the outer shape of the wave-absorbing unit 3 from all directions.
And a hollow chamber 9 is provided in the inside thereof, and an opening is formed in the wave-absorbing wall 5 at a position below the design high tide level (HWL) and facing the main wave direction S. 1
1, the opening 11 allowed the hollow chamber 9 to communicate with the outside sea. Therefore, a sufficient wave-eliminating effect can be expected without being affected by the wave directions S in all directions, and the structure can be used as an environment-creating structure.

In this case, as in the invention described in claim 2,
The hemispherical wave-absorbing wall 13 in which the wave-absorbing wall 5 is formed in a substantially hemispherical shape, or the wave-absorbing wall 5 having a circular cross section having a diameter gradually reduced as in the invention according to claim 3, are concentrically superimposed on each other to form a staircase. If the wave-eliminating unit 3 having the step-like wave-eliminating wall 15 formed in a shape is used, the reflected wave height and the transmitted wave height can be suppressed to be small, and the stability as well as the hydraulic function can be improved.

Further, as in the wave canceling structure described in claim 4, a valve mechanism 23 is provided in the hollow chamber 9, and energy of waves entering and exiting from the opening 11 of the wave canceling wall 5 is transferred to the valve mechanism. 23 so that it can be converted to air energy,
Wave energy can be used for power generation systems and the like. By arranging the wave breaking units 3 in one or more rows in a direction orthogonal to the wave direction S as described in claim 5, it is possible to constitute a breakwater or the like. In this case, if a plurality of rows of wave-breaking units 3 are arranged in a staggered manner so as to circumscribe each other, adjacent wave-breaking units 3,
Since seawater flows in and out along the gap between the three, the water quality environment in the rear area can be favorably maintained.

If the wave-breaking units 3 are arranged along the main wave direction S, preferably in a plurality of rows, as described in claim 6, the wave-breaking units 3 can be effectively used for secondary wave directions. It can be used as a functioning jetty, and the wave breaking unit 3 can be arranged in a headland shape. Furthermore, as described in claim 8, if the outer portion of the wave-dissipating unit 3 is formed as a natural stone-like pseudo-rock, it can be used as a scenic element of a coast that harmonizes with nature.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the wave-absorbing structure of the present invention will be described in detail below. The present invention is not limited to the following embodiments, and it goes without saying that various design changes can be made without departing from the technical idea of the present invention. The wave-dissipating structure according to the first aspect of the present invention is generally composed of a plurality of wave-dissipating units 3. For example, as shown in FIG. 1B, the wave canceling unit 3 is arranged such that the wave canceling unit 3 is adjacently arranged in a line along a direction orthogonal to the wave direction S, or as shown in FIG. As described above, the wave-dissipating units 3 are arranged in a plurality of rows along the direction orthogonal to the wave direction S, and are arranged in a staggered manner so that each of the wave-dissipating units 3... (See claim 5).

[0011] As shown in FIG.
It is arranged on a base 1 such as a mound or a concrete slab formed in the sea (sea bottom) in the coastal sea area facing the open sea. Wave-absorbing wall 5 forming the outer shape of each wave-absorbing unit 3
Are formed in an arc shape with respect to the wave direction S of the waves coming from all directions. Further, a hollow chamber 9 is provided inside the wave canceling unit 3, and the hollow chamber 9 and the outside of the sea are below the designed high tide level (HWL) and the main wave direction S (See FIG. 4).

The wave-absorbing wall 5 of the wave-absorbing unit 3 is formed in a hemispherical shape (spherical surface) having a diameter of about 15 m by concrete in order to form an arc with respect to the omnidirectional wave direction S. . According to the hemispherical wave-absorbing unit 3 formed on the hemispherical wave-absorbing wall 13, since the wave wraps around the spherical surface, the reflected wave height is higher than that of a conventional structure having an upright wall as in the related art. Due to the effect of the shallow spherical surface, the waves converge on the wave-absorbing unit 3 to promote breaking waves, and the transmitted wave height is also reduced due to the attenuation of energy due to the collision of the wave wrapping behind the wave-absorbing unit 3. can do. Further, since the shielding area is reduced, the seawater exchange is not hindered, and the wave-dissipating hydraulic function can be improved regardless of the wave direction. Furthermore, this hemispherical wave-absorbing wall 1
According to No. 3, since the wave force acts in the center direction along the spherical surface, the horizontal component is reduced, so that the sliding resistance is increased as compared with the structure having the upright wall, and the weight can be reduced, and the reflection can be reduced. Since the wave height is small and the water level change at the front is small, scouring at a method tip such as a mound can be suppressed, so that stability can be enhanced.

As means for forming the above-mentioned wave-absorbing wall 5 in an arc shape with respect to the wave direction S, the wave-absorbing wall S having a circular cross section whose diameter is sequentially reduced is concentrically superimposed. It is also preferable to use the wave-eliminating unit 3 formed in a step shape (curved surface shape) (FIG. 3). This step-like wave-breaking wall 1
According to the step-type wave-eliminating unit 3 formed in 5, the reflected wave height is reduced as compared with the structure having the upright wall as in the case of the above-described hemispherical structure, and the effect of the pseudo spherical shallow water is obtained. Accordingly, the transmitted wave height can be reduced.
Similarly, since the shielding area is also reduced, the exchange of seawater is not hindered, and furthermore, the wave-dissipating hydraulic function can be improved regardless of the wave direction. In the step portion of the step-like wave-absorbing wall 15, not only a phase difference is generated in the horizontal wave force of each step, but also the horizontal component is reduced, so that it is advantageous as compared with the structure having the upright wall to which the horizontal force is applied simultaneously. Becomes In addition, when horizontal force is applied to the upper stage, a vertical load increases because a water mass is placed on the lower stage, the stability increases due to the synergistic effect with the reduction effect of the horizontal force, and the reflected wave height is also small, so it is a hemispherical shape Similarly, stability can be increased.

Therefore, in the wave-absorbing structure constructed as described above, when the wave water which has been pushed in from the direction of the symbol S in the drawing enters and exits the hollow chamber 9 through the opening 11, the water particles in the hollow chamber 9 The energy is effectively absorbed by the disturbance and friction of the water and the pressure change, etc., and the waves on the sea are formed in a wave-shaping wall 5 (hemispherical wave-shaping wall 13, step-like wave-shaping wall 15) formed in an arc with respect to the wave direction S. ) Absorbs wave energy as described above, and performs wave extinction. Further, the hollow chamber 9 inside the wave-dissipating unit 3 communicates with the outside through the opening 11, so that it also functions as a fish reef.

As shown in FIG. 2, when the wave eliminating units 3 arranged in a plurality of rows are arranged in a staggered manner so as to be circumscribed, along the gap between the adjacent wave canceling units 3, 3. As seawater flows in and out, it is possible to maintain a favorable water quality environment in the rear area. At this time, the wave breaking function can be enhanced by appropriately arranging the filling stones in the gap. As shown in FIG. 4, a part of the hollow chamber 9 provided inside the wave canceling unit 3 is partitioned by a partition wall 17 to form an outside air chamber 19, and a valve mechanism 23 is provided in an opening of the partition wall 17. In addition, by connecting the air supply pipe 25 of the valve mechanism section 23 to, for example, a constant pressure tank (not shown) installed in the hinterland, the valve mechanism section 23 converts wave energy into air energy. (Claim 4).
Note that an outside air intake 27 is provided in a part of the wave breaking wall 13 of the wave breaking unit 3.

According to this embodiment, when the water level drops due to the wave as shown in FIG. 5A, the pressure in the hollow chamber 9 decreases, and the ball (valve element) 29 of the valve mechanism 23 is caused by its own weight and the pressure drop. The air supply valve 31 is closed by the suction force,
The balls (valve elements) 35, 35 float by the suction force and open the intake valves 33, 33, so that outside air flows into the hollow chamber 9 from the outside air chamber 19. On the other hand, when the water level rises as shown in FIG. 5B, when the air in the hollow chamber 9 is compressed and becomes higher than a predetermined pressure, the balls 35, 35 close the intake valves 33, 33 and push the ball 29 up. The air supply valve 31 is opened and compressed air is sent to the air supply pipe 25. By repeating this operation, compressed air is stored in the constant-pressure tank via the air supply pipe 25, and this air energy can be used as a drive source for, for example, aeration in the rear region or a power generation device. .

In the above-described embodiment, the case where the wave-breaking structure is used as a breakwater has been described. However, as shown in FIG. 8, the wave-breaking units 3 may be arranged in a headland shape. Alternatively, as shown in FIG. 9, an embodiment in which the wave-dissipating units 3 are arranged in a plurality of rows along the main wave direction and used as a jetty (claim 6) is also suitably adopted. Also in this case, since the wave-absorbing wall 5 is formed in an arc shape (hemispherical in the illustrated example) with respect to the wave direction S, the direction is oblique to the direction in which the wave-absorbing units 3 are arranged or a direction shifted from the main wave direction S. Thus, even if a wave strikes, not only can a sufficient wave-dissipating hydraulic function be obtained, but also because it has permeability, it is possible to prevent inconveniences such as inhibiting seawater exchange.

It is to be noted that, as in claim 8, the wave canceling unit 3
6, preferably the entire outer part exposed to the sea from slightly below the design high tide (HWL) is shown in FIG.
As shown in the above, by covering with a pseudo-rock 37 formed like a natural stone, the wave-dissipating structure itself can be formed as a reef or an island that produced greening, and as a scenic element of the coast that harmonizes with nature. Available (Figure 7). In the case of this embodiment, the mode shown in FIG. 7 in which the wave-dissipating units 3 are individually installed as a single unit in the coastal sea area is generally used. Good (see FIGS. 8 and 9).

[0019]

EXAMPLE A model experiment on the wave-breaking function when a wave-breaking structure was used as a breakwater was conducted.
The result as shown in FIG. In this model experiment, the reflectivity and the transmittance of a wave were obtained under the following experimental conditions (including [Table 1]) with reference to the actual measurement data of the wave, assuming a shallow sandy beach. Experimental conditions Experimental water tank; 2D wave-making water tank (length: 20.5 m, width: 1.5 m, depth: 1.2 m) Model scale: 1/50 Similarity rule of Froude Wave height Hm / Hp = 1/50 period Tm / Tp = 1 / 7.0 model arrangement; hemispherical type [five hemispherical wave-dissipating units are arranged adjacent to each other in a row along the direction perpendicular to the wave direction (see Fig. 1B)], step-like type [ Wave-dissipating units of circular cross-section, whose diameters are set sequentially smaller, are concentrically superimposed and formed in a staircase-like shape. The two units are circumscribed in two rows along the direction perpendicular to the wave direction. (See FIG. 3B).

[0020]

[Table 1]

In Table 1, the values in parentheses in the column of wave height are local quantities when the scale is assumed to be 1/50. 10 to 13 are all dimensionlessly displayed. On the other hand, the MMZ target value is a target value of the wave-cancelling function presented in the MMZ concept. According to the experimental results, the hemispherical reflectance (FIG. 10) and the staircase reflectance (FIG. 12) are both 0.4 or less, and the hemispherical transmittance (FIG. 11) and the staircase transmittance (FIG. 13) are the ranges of 0.5 to 0.4 and 0.4 to 0.3, respectively, and all the data have the MMZ target values (reflectance = 0.5, transmittance = 0.6). It was confirmed that they were satisfied. Therefore,
The wave-dissipating structure according to the present invention can be expected to have a sufficient wave-dissipating function even in an actual sea area.

[0022]

According to the wave-absorbing structure according to the first to third aspects of the present invention, the wave-absorbing wall of the wave-absorbing unit is formed in an arc shape such as a hemisphere or a step shape with respect to the omnidirectional wave direction, A hollow chamber is provided therein, and the hollow chamber and the outside are communicated with each other by an opening provided below a designed high tide level (HWL), so that waves are not affected by the wave direction. In addition to being able to reliably attenuate energy and eliminate waves,
It also has the function of a fish reef, so the added value can be increased. In the back area where the wave-breaking structure is installed, a calm sea area is secured by the wave-breaking effect and good seawater exchange, so it can be used as a place for leisure and fisheries, and the beach should be preserved and stabilized. Therefore, it can contribute to the formation of habitat and growth environment for various aquatic organisms, and is therefore optimal as a next-generation environment-creating wave-dissipating structure.

Further, as in the wave-absorbing structure according to the fourth aspect, the valve mechanism provided in the wave-absorbing unit converts wave energy into air energy to perform aeration for purifying water quality and driving of the power generator. It can be used for multiple purposes such as sources, and the overall shape is an image that is friendly to the global environment. In particular, when covered with artificial stones like natural stones as in claim 8, it is possible to repair coasts that are in harmony with nature. It can be used as a landscape element.

Furthermore, not only is the stability of the wave-breaking unit high, but also various advantages are obtained, such as being economical because a structure can be constructed by appropriately combining the wave-breaking units.

[Brief description of the drawings]

FIGS. 1A and 1B are a side view and a plan view when a wave-dissipating structure is used as a breakwater.

FIGS. 2A and 2B are a front view and a plan view, respectively, when a wave-dissipating structure is used as a breakwater.

FIGS. 3A and 3B are still another side view and a plan view when the wave-dissipating structure is used as a breakwater.

4A is a plan view of the wave canceling unit, and FIG. 4B is a cross-sectional view of A taken along the line BB.

5A and 5B are explanatory diagrams of a valve mechanism in the wave canceling unit shown in FIG. 4;

FIG. 6 is a side view of the wave-dissipating unit formed with pseudo rocks.

FIG. 7 is a bird's-eye view of the wave canceling unit shown in FIG. 6;

FIG. 8 is a bird's-eye view when the wave-dissipating structure is used as a head land.

FIG. 9 is a bird's-eye view when the wave-dissipating structure is used as a jetty.

FIG. 10 is a graph showing the reflectivity of waves obtained by a model experiment of a breakwater using a hemispherical type wave-dissipating unit.

FIG. 11 is a graph showing wave transmittance obtained by a model experiment of a breakwater using a hemispherical type wave-dissipating unit.

FIG. 12 is a graph showing the wave reflectance obtained by a model experiment of a breakwater using a staircase-type wave-dissipating unit.

FIG. 13 is a graph showing wave transmittance obtained by a model experiment of a breakwater using a staircase-type wave breaking unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 3 Wave-dissipating unit 5 Wave-dissipating wall 9 Hollow room 11 Opening 13 Hemispherical wave-dissipating wall 15 Stair-shaped wave-dissipating wall 23 Valve mechanism 37 Fake rock

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hidenori Chino 1-5-1, Otsuka, Inzai City, Chiba Pref. No. 1 Inside Takenaka Corporation Tokyo Main Store (72) Inventor Minoru Kawaharada 8-21-1, Ginza, Chuo-ku, Tokyo Inside Tokyo Main Branch Takenaka Corporation (72) Inventor Kiyoshi Nishihara Ginza, Chuo-ku, Tokyo 8-21-1, Takenaka Civil Engineering Co., Ltd. (72) Minor Hasegawa, Inventor Minami Hachimatsu, Minato-ku, Tokyo Minato-ku, Tokyo Minato-ku, Tokyo No. 20-10, Tetra Tokyo Sales Office (72) Inventor Yusaku Toyoda Hachigo Komachi Nakamachi, Chuo-ku, Kobe City, Hyogo Prefecture Inside Tetra Kobe Reconstruction Office (72) Who Minoru Hanzawa Tsuchiura, Ibaraki Prefecture Higashinakanuki-cho, 2-7, Ltd. Te tiger application Hydraulic the laboratory (72) inventor Nishikori Kazunoriro Tsuchiura, Ibaraki Prefecture Higashinakanuki-cho, 2-7, Ltd. Te tiger application Hydraulic Institute in the

Claims (8)

[Claims] 1. A wave-dissipating wall which is constituted by one or two or more wave-dissipating units installed on an undersea base, and which has an outer shape of the wave-dissipating unit, is formed in an arc shape with respect to the wave direction in all directions. A hollow chamber is provided therein, and an opening is provided in the wave-absorbing wall at a position below the design high tide level and opposed to the main wave direction, and the hollow is provided through the opening. A wave-dissipating structure characterized by communication between a room and the outside of the sea. 2. The wave-breaking structure according to claim 1, wherein the wave-breaking wall is constituted by a wave-breaking unit formed in a substantially hemispherical shape. 3. The wave-dissipating unit according to claim 1, characterized in that the wave-dissipating wall having a circular cross section whose diameter is set to be sequentially smaller is concentrically superimposed and formed in a stepwise shape. Wave-dissipating structure. 4. A structure in which a valve mechanism is provided in a hollow chamber of the wave-dissipating unit, and energy of wave-dissipation entering and exiting from an opening of the wave-dissipating wall can be converted into air energy by the valve mechanism. The wave-absorbing structure according to any one of claims 1 to 3, characterized in that: 5. The wave elimination unit according to claim 1, wherein the wave elimination units are arranged in one or more rows along a direction orthogonal to the wave direction. Structure. 6. The wave-dissipating structure according to claim 1, wherein the wave-dissipating units are arranged along a main wave direction. 7. The method according to claim 1, wherein the wave canceling unit is arranged in a head land shape.
Wave-dissipating structure described in the paragraph. 8. The wave-dissipating structure according to claim 1, wherein an outer portion of the wave-dissipating unit is formed as a natural stone-like pseudo rock.