JPH11241323A - Breakwater structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a breakwater structure which is erected at the seaside facing the offing, for preventing the sliding and falling-down thereof by providing a high wave-blocking characteristic excellent in stability, and by restricting the vertical wave force as low as possible acting to push up the breakwater structure upward. SOLUTION: A offing-side wall surface 10 is provided with an upper inclined surface 11 inclined toward the offing side so as to repulse the waves coming from the offing, and is also provided with a lower inclined surface 12 inclined to the land side. Thus, the upward component force of the wave pressure acting on the upper inclined surface 11 is offset against the downward component force of the wave pressure acting on the lower inclined surface 12 to reduce the vertical wave force acting on the breakwater structure body 50 so as to push it upward.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a breakwater and a breakwater structure for revetment installed in a harbor or the like.

[0002]

2. Description of the Related Art FIG. 15 shows a conventional wavebreak structure. This wavebreaking structure is formed by digging down the sea floor, replacing the ground with sand 41, improving the ground, and then providing a rubble mount 42 to form a foundation 40, on which a wavebreaking structure body 50 made of an upright caisson is mounted. It is configured to be mounted.

[0003] In such a breakwater structure, in order to protect ships, buildings, and the like located on the land side of the breakwater structure from waves, it is necessary to prevent waves from passing over the wavebreak structure body 50. It is necessary to set the top end height (the height from the still water surface S to the upper surface of the wave-breaking structure main body 50) sufficient for this.

[0004] However, if the height of the top end is increased, the scenery is significantly impaired. Therefore, there is a need for a wavebreaking structure having excellent non-overtopping characteristics capable of preventing overtopping while suppressing the height of the top end. ing. Therefore, recently, a breakwater structure having high non-overtopping characteristics by making the offshore wall surface 10 an arc surface has been proposed.

FIG. 16 shows a wave-breaking structure in which the offshore wall surface 10 has an arc shape (hereinafter referred to as a “flare-type” wave-breaking structure). This flare-type breakwater structure obtains excellent non-overtopping characteristics by repelling waves offshore by the arc-shaped offshore wall surface 10.

[0006]

However, in such a flare type wave-proof structure, since the upper part of the offshore wall surface 10 protrudes so as to be inclined to the offshore side, the wave-proof structure main body 50 is formed.
However, there is a problem that the contact area is small and stability is lacking.

In this flare type breakwater structure, the direction of movement of the water mass colliding with the offshore wall surface 10 is determined by the arc surface 10.
The wave pressure generated on the offshore wall surface 10 due to the forcible change along the sea surface is generated in the offshore wall surface 10 because the flare-type breakwater structure has an upper part protruding offshore. The wave pressure p acting on any position is the vertical component force component p _z
, And the sum of the upward vertical wave force _Fz is very large.

[0008] If the action such large vertical wave force F _z is the breakwater structure body 50, to act to push up the breakwater structure body 50 upwardly, breakwater structure body 5
This causes a reduction in the frictional resistance at the bottom surface 0, and causes a problem that the wavebreak structure main body 50 easily slides in a substantially horizontal direction.

Further, if a large vertical wave force _Fz acts,
There is also a problem that the wavebreak structure main body 50 is likely to fall over.

Therefore, in order to prevent such sliding and overturning, the volume and weight of the wave-breaking structure main body 50 must be increased, and the cost required for production and construction increases. Furthermore, if the volume and weight of the wave-breaking structure main body 50 increase, the foundation 40 supporting the same also increases in size,
The cost and time required for construction such as ground improvement will also increase.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a high non-overtopping property, is excellent in stability, and acts to push up a wave-breaking structure body upward. An object of the present invention is to provide a breakwater structure in which the vertical wave force is kept low.

[0012]

Means for Solving the Problems In order to solve the above-mentioned problems, a wave-breaking structure according to the present invention is a wave-breaking structure that is erected facing offshore. An upper slope that slopes offshore is provided so as to protrude toward the ocean, and a lower slope that slopes toward land is provided below the offshore wall surface so as to approach the offshore side. (Claim 1).

According to this configuration, since the upper slope provided at the upper part of the offshore wall slopes offshore so as to approach the offshore side, the wave colliding with the offshore wall as a water mass is formed. Is bounced offshore to prevent overtopping. In addition, since the lower slope provided at the lower part of the offshore wall slopes toward the land so as to protrude offshore, the vertical upward component of the wave pressure acting on the upper slope of the offshore wall The component is offset by the vertically downward component force component of the wave pressure acting on the lower inclined surface, and the vertical wave force acting to push the wavebreaker structure body upward is reduced. Further, since the lower inclined surface is inclined toward the land, the bottom area of the main body of the wave-breaking structure increases, and high stability of the main body of the wave-breaking structure can be obtained.

In order to prevent the overtopping by the offshore wall surface and to keep the height of the top of the breakwater structure low,
It is required that the upper inclined surface provided above the offshore wall surface sufficiently repels waves that collide with the offshore wall surface as water. For this reason, this upper inclined surface is configured so that the horizontal length D of the protrusion toward the offshore side is 0.2 or more in a ratio D / B to the height B of the offshore wall surface. Is desirable (claim 2). On the other hand, if the upper inclined surface excessively protrudes offshore, the wave pressure generated on the upper inclined surface increases, and the strength required for the wave-breaking structure body to support the upper inclined surface is extremely high. Therefore, it is desirable that the upper inclined surface be configured such that the ratio D / B is 1.5 or less (claim 2).

Here, the upper part of the offshore wall surface on which the upper inclined surface is provided means at least a part including a part that receives a wave reaching the breakwater structure, and a specific range thereof may be appropriately set. Specifically, the upper inclined surface is preferably provided in a region including the still water level position (claim 3).

Further, at least a part of such offshore wall surface may be constituted by a flat surface.
With this configuration, at least a part of the offshore wall surface configured as a flat portion can be easily manufactured, so that the cost and time required for manufacturing the wavebreak structure are reduced.

Further, it is preferable that the offshore wall surface is formed so as to have a concave shape as a whole toward the offshore. With this configuration, since there is no convex portion that hinders the smooth movement of the water mass moving along the offshore wall surface, the waves colliding with the offshore wall surface as a water mass are:
It smoothly moves along this offshore surface and bounces offshore, providing excellent non-overtopping characteristics, and reducing the impact on the offshore surface due to water bodies moving along this offshore surface. Is done. In addition, the offshore wall surface may be constituted only by a curved surface, may be constituted only by a flat surface, or may be constituted by a combination of a curved surface and a flat surface, as long as the shape is concave toward the offshore as a whole. Good.

[0018] Further, it is preferable that an upper portion of the offshore wall surface including the upper inclined surface is formed as a curvature continuous surface having a continuous curvature. With this configuration,
Since there is no discontinuity in the curvature that hinders the smooth movement of the water mass moving along the offshore surface, the waves that collide with the offshore surface as a water mass move smoothly along the offshore surface. The water is rebounded offshore to provide excellent non-overtopping characteristics, and the wave pressure acting on the offshore surface is continuously changed by the water mass moving along the offshore surface. The stress concentration occurring on the offshore wall is reduced. In addition, since the plane is a plane having zero curvature, the curvature continuous plane may include a plane. It is desirable that the upper portion including the upper inclined surface of the offshore wall surface is a region including a portion of the offshore wall surface where a wave as a water mass moves along the offshore wall surface.

Further, it is desirable that such a continuous curvature surface is formed over the entire offshore wall surface. With this configuration, it is possible to smoothly move the water mass moving along the offshore wall surface over the entire offshore wall surface, and further excellent non-overtopping characteristics as a breakwater structure. As a result, stress concentration due to wave pressure can be reduced over the entire offshore wall surface.

Furthermore, it is preferable that at least the upper portion of the curvature continuous surface is configured such that the curvature gradually decreases toward the upper portion. With this configuration, the rate of change of the direction of movement of the water mass moving along the offshore surface becomes smaller toward the upper part of the offshore surface, and the wave pressure acting on the offshore surface with the change in the movement direction is reduced. Becomes smaller. Therefore, the wave pressure acting on the offshore wall surface gradually decreases toward the upper part of the offshore surface surface where the vertically upward component force component of the acting wave pressure is large. Wave power can be reduced. The portion in which the curvature gradually decreases toward the upper portion may be formed at least on an upper portion of the portion configured as the curvature continuous surface, but may be formed on the entire curvature continuous surface. In particular, the upper part of the offshore wall, including the part where the waves of water move along the offshore wall, including the upper slope of the offshore wall, has such a curvature gradually decreasing upward. It is desirable to be constituted so that.

[0021]

FIG. 1 shows a first embodiment of a wavebreak structure according to the present invention.

This wave-breaking structure is similar to the conventional wave-breaking structure shown in FIG. 15 in that a wave-breaking structure main body 50 is installed on a foundation 40 composed of sand 41 and a rubble mount 42. It is configured. In addition, this wave-proof structure body 5
On the offshore side of zero, a wave breaker 60 made of a tetrapod or the like is provided in order to reduce the strength of incoming waves. In addition,
The foundation 40 and the wave breaker 60 are not essential, and are not limited to such a configuration, and may have any known configuration.

FIG. 2 shows a cross-sectional shape of the main body 50 of the wave-proof structure.

As shown in FIG.
0 is an upper inclined surface 11 inclined toward the offshore side so as to protrude toward the offshore side above the offshore wall surface 10 and a land side so as to protrude toward the offshore side below the offshore wall surface 10. A lower inclined surface 12 is provided.

The upper inclined surface 11 is a portion for receiving a wave coming from the offshore side and rebounding offshore to prevent overtopping. Therefore, the upper inclined surface 11 always includes the height position 91 of the still water surface S including the low tide and the high tide when installed on the coast, so that the incoming wave can be received. The region is formed from the lower side than the water surface height position 92 when the wave W having the designed maximum wave height is drawn, over the top end position of the offshore wall surface 10. The design maximum wave height refers to the maximum wave height assumed in the sea area where the breakwater structure is installed, and is set for designing the breakwater structure.

Note that the main body 50 has a vertical surface above the upper inclined surface 11 of the offshore wall surface 10, and this vertical surface is formed as a part of the upper inclined surface 11 described above. It does not fulfill the function of receiving and repelling, and the uppermost portion of the upper inclined surface 11 withstands the wave pressure acting when receiving and repelling waves as the upper inclined surface 11, and has a certain strength required as a structure. It forms the thickness necessary to obtain. For this reason, in this specification, such a substantially vertical surface portion is not included in the offshore wall surface 10.

Therefore, except for the vertical plane which is not included in the offshore wall surface 10, the offshore wall surface 10 of the breakwater structure according to the first embodiment has the upper inclined surface 11 and the lower inclined surface 1.
2 and the entire surface is a curvature continuous surface having a continuous curvature, and is configured so as to have a concave shape as a whole toward the offshore by a curved surface having a gradually decreasing curvature toward an upper portion.

This breakwater structure on which such an offshore wall surface 10 is formed arrives offshore, and is formed as a water mass on the offshore wall surface 1.
The wave colliding with zero is moved upward along the offshore wall surface 10 and bounces off the sea surface offshore from the wavebreaking structure main body 50 along the upper inclined surface 11 inclined offshore, thereby causing overtopping. It can be stopped.

The wave-breaking structure is used for such an offshore side wall 1
In order to reduce the top height of the breakwater structure while preventing wave overtopping by 0, the upper inclined surface 11 provided above the offshore wall surface 10 collides with the offshore wall surface 10 as a water mass. It is necessary to sufficiently repel the waves. Therefore, the upper inclined surface 11 has a horizontal length D that protrudes to the offshore side in a ratio D to the height B of the offshore wall surface 10.
/ B is preferably 0.2 or more. On the other hand, when the upper inclined surface 11 excessively protrudes offshore, the wave pressure generated on the upper inclined surface 11 increases, and the wave-breaking structure body 50 is required to support the upper inclined surface 11. The ratio D / B is desirably suppressed to about 1.5 or less, since the resulting strength becomes extremely large.

Also, if a wave as a body of water moves along the offshore wall surface 10 when it rebounds offshore, the offshore wall surface 1
At 0, the wave pressure p acts in the normal direction. Of the wave pressure p acting on the offshore wall surface 10, the wave pressure p acting on the upper inclined surface 11 is a vertical upward component force. Component p _z
Therefore, the sum of the component force components p _z forms an upward vertical wave force F _z ^′ acting to lift the breakwater structure main body 50 upward. On the other hand, the wave pressure p acting on the lower slope 12
Because having a vertically downward component force component p _z, the sum of the component force component p _z forms a ^'downward vertical wave force F _z which acts to offset ^the' vertical wave force F _z wherein upward.

As described above, since the wave-breaking structure has the lower inclined surface inclined to the land side, the upward vertical wave force F _z ^′ due to the wave pressure acting on the upper inclined surface 11 is generated by the lower inclined surface. 12, offset by the downward vertical wave force F _z ^″ acting on
As a result, it is possible to reduce the upward vertical wave force acting to lift the wavebreak structure main body 50.

In order for this wave-breaking structure to reduce the upward vertical wave force as described above, it is necessary to reduce the upward vertical wave force F _z ^′ by acting on the offshore side of the upper inclined surface 11 in the horizontal direction. With respect to the length D, the lower inclined surface 12 on which the downward vertical wave force _Fz ^″ acts is also required to have a constant horizontal length protruding offshore. Therefore, it is desirable that the length b of the portion where the upper inclined surface 11 protrudes offshore from the lower inclined surface 12 is 0.5D or less. In order to increase the contact area of the main body of the breakwater structure and obtain high stability, it is desirable that the length b is small. Further, the lower inclined surface 12 is protruded offshore from the upper inclined surface 11. May be configured.

The offshore wall surface 10 of the breakwater structure is
Since it is constituted by a concave curved surface having a continuous curvature, a wave colliding with the offshore wall surface 10 as a body of water can be smoothly moved along the offshore wall surface 10 and bounce off the offshore side. The non-overtopping characteristic can be obtained. Further, since the offshore wall surface 10 does not have a convex portion or a discontinuous curvature portion, it is possible to reduce the impact and stress concentration on the offshore wall surface 10 due to the water mass moving along the offshore wall surface 10. Can be.

Further, since the offshore wall surface 10 is formed as a continuous surface of curvature in which the curvature gradually decreases toward the upper part, the offshore wall surface 10 is directed toward the upper part of the offshore wall surface where the vertically upward component component of the acting wave pressure is large. As a result, the wave pressure acting on the offshore wall surface 10 decreases with the change in the direction of movement of the water mass moving along the offshore wall surface 10, and the vertical wave force acting on the breakwater structure body is further reduced. it can.

Next, non-overtopping characteristics of the breakwater structure according to the first embodiment will be examined by a scale model experiment. In the following description, for the sake of convenience, the waveproof structure according to this embodiment is referred to as a “flare type with a footing” waveproof structure in which a lower inclined surface (footing) 12 is formed. Call an object.

FIG. 10 shows an apparatus used in this experiment.
As shown in the figure, this experiment was conducted in a two-dimensional wave-making water tank (length 20.0 m, height 1.2 m, width 0.6 m).
/ 20 slope 72 on offshore surface 10 of various shapes
A wave model having various wave heights formed by the wave making device 71 is incident on this scale model while installing the scale model of the wavebreaking structure main body 50 provided with
The critical top height h _c at which overtopping occurs was determined by visually checking the presence or absence of overtopping. In this experiment, an incoming wave was made to directly collide with the wave-breaking structure main body 50 without providing the wave breaker 60.

FIG. 11 shows the offshore wall surface 1 of each of the flare type with footing, the flare type, and the upright type used in this experiment.
0 shows the cross-sectional shape. As shown in the figure, all models have the same offshore wall surface height B = 22.5 cm, and for the flare type with footing and the flare type, the excavation depth relative to the offshore wall surface height B ( Depth of depth) D
The ratio D / B of the flare type with footing is 0.53,
In the flare type, a value substantially equal to 0.5 is set so that the experimental conditions are equivalent.

FIG. 12 shows the results of the experiment. Each plot in the figure, the original waveform gradient H ₀ / L ₀ = 0.036, where various wave height H ₀ = 8.0cm~14.0cm is incident on the offshore side wall of each model FIG. 6 shows the critical top height h _c / H ₀ with respect to the relative installation water depth h / H ₀ . As described above, the critical crown height h _c is the height of the offshore wall surface from the still water surface S to the crown required to prevent the incident wave from overtopping. A lower value indicates that the non-overtopping characteristic is more excellent.

From the experimental results shown in this figure, it can be seen that the flare type model with footing indicated by ● and the flare type model indicated by □ in the figure are superior to the upright type model indicated by ○ in non-overtopping characteristics. I understand. For this reason, the flare type model with footing and the flare type model are excellent in that the direction of motion of the wave that the inclined surface provided at the upper part of the offshore wall surface 10 common to both collides as a water mass rebounds offshore. It is inferred that non-overtopping characteristics have been obtained.

The experimental results show that the flare type model with footing is slightly better than the flare type model but has almost the same non-overtopping characteristics. From this, it is presumed that whether or not the shape of the lower portion of the offshore side wall surface 10 that is different between them protrudes toward the offshore side does not significantly affect the non-overtopping characteristic.

Next, the vertical wave force acting on the flare type breakwater structure with footing will be described with reference to FIG.
This is examined by an experiment using a two-dimensional wave-making water tank 70 shown in FIG. 0 and a scale model of a flare type with a footing, a flare type, and an upright type shown in FIG.

In this experiment, the wave pressure distribution acting on the offshore wall surface 10 was obtained from a reduced scale model in which pressure sensors were provided at a plurality of height positions on the offshore wall surface 10, and each height position was obtained from this wave pressure distribution. The vertical wave force acting on each model was obtained by integrating only the vertical component of the wave pressure.

FIG. 13 shows an example of the measurement results of the wave pressure.
In the figure, the vertical axis represents the measurement position Z with the hydrostatic surface height S being 0, and the dimension is shown dimensionlessly with the offshore wall surface height B,
The horizontal axis shows the average value P of the wave pressure acting on the measurement position in a dimensionless manner with the density ρ of water, the gravitational acceleration g, and the wave height H ₀ . Also, as in FIG. 10, the black circles indicate the actual measurement results of the flare type model with footing, the black squares indicate the actual measurement results of the flare type model, and the black circles indicate the measurement results of the upright side model.

The experimental results shown in FIG.
This is a wave pressure distribution when the wave height H ₀ = 14.0 cm is set under the condition of 5.0 cm and the waveform gradient H ₀ / L ₀ = 0.036. Here, we make several experiments with different wave height H _0, for each model, to obtain a wave pressure distribution for waves of various wave height H _0.

From the thus obtained wave pressure distributions for the waves of various wave heights H ₀ , the vertical component force component of the wave pressure is determined by taking into account the gradient of the offshore wall surface 10 at each height position. obtained by integrating this over the entire offshore wall 10, a vertical wave force F _z acting on the breakwater structure body 50 is obtained for each condition.

[0046] FIG. 14 shows the results of measurement of the vertical wave force F _z. In the figure, the vertical axis shows the vertical wave force F _z obtained by the integral calculation of the above-described density of water [rho, the gravitational acceleration g, and dimensionless with the wave height H ₀ and offshore wall height B There, the horizontal axis represents the experimental conditions by the ratio of the water depth h and the height H _0.

From the experimental results shown in this figure, the vertical wave force acting on the flare type model with footing shown by ● in the figure is 1/1 / the vertical wave force acting on the flare type model shown by □.
It turns out that it is 2 or less. This is because the flare type model with footing is different from the flare type model in that the lower inclined surface 12 provided at the lower part of the offshore wall surface 10 is inclined to the land side, so that the wave pressure acting on the lower inclined surface 12 Has a downward component component, and the upper inclined surface 11
Offset the upward component force components Nami圧acting on, presumably because that reduces the vertical wave force F _z to be the sum of these.

The offshore wall surface 1 of the upright model indicated by ○
0 naturally vertically wave force F _z for a vertical plane does not act.

As can be seen from the above experiment, according to the flare type breakwater structure with footing according to the first embodiment, the upper inclined surface 11 that is provided on the offshore wall surface 10 and that is inclined offshore. Has remarkable non-overtopping characteristics as compared with the conventional upright type breakwater structure. Therefore, overtopping can be prevented at a low top end height.

Further, in the flare type breakwater structure with a footing, the lower inclined surface 12 provided on the lower part of the offshore wall surface 10 and inclined toward the land side does not deteriorate the non-overtopping characteristic. Since the upward component of the wave pressure acting on the upper inclined surface 11 is offset by the downward component of the wave pressure acting on the lower inclined surface 12, a comparison is made with a flare-type breakwater structure having similar non-overtopping characteristics. , it is possible to reduce the vertical wave force F _z acting on the breakwater structure body 50. Therefore, it is possible to reduce the weight of the wave-preventing structure main body 50 while preventing the sliding and overturning of the wave-preventing structure main body 50, and to reduce the cost and time by reducing the required foundation 40. .

In this flare type breakwater structure with footing, since the lower inclined surface 12 is inclined to the land side,
Compared to the flare-type wavebreak structure, the wavebreak structure main body 50
It is also excellent in stability because the ground area of the lower surface can be increased.

Second Embodiment (FIG. 3) In the following description of the embodiment, components having the same functions and effects as those of the first embodiment will be denoted by the same reference numerals as those of the first embodiment. Description is omitted.

In the second embodiment, the offshore wall surface 10 is constituted by a plurality of planes 111, 112, 121, 122 and 123 having different inclination angles. Among the plurality of planes constituting the offshore wall surface 10, the planes 111, 11
2 forms an upper inclined surface 11 inclined to the offshore side,
1, 122, 123 form the lower inclined surface 12 inclined to the land side.

As described above, if the offshore wall surface 10 is constituted by a combination of a plurality of planes, when the wave-breaking structure main body 50 is constituted by reinforced concrete or the like, the flat portion does not require bending of the reinforcing bar, and When molding concrete, a mold made of a flat surface can be used, so that it can be easily manufactured, and the manufacturing cost and time can be reduced.

If the offshore wall surface 10 is formed of only a plurality of planes, the offshore wall surface 10 has a discontinuous curvature. However, as shown in this embodiment, the offshore wall surface 10 is generally concave toward the offshore. A configuration having no convex portion of the shape can be adopted.

Third Embodiment (FIG. 4) In this embodiment, the upper inclined surface 11 of the offshore wall surface 10 is constituted by one plane 113, and the lower inclined surface 12 is constituted by one plane 124 similarly. . In this way, if the offshore wall surface 10 is composed of only two planes, the breakwater structure main body 50 can be manufactured particularly easily.

Fourth Embodiment (FIG. 5) In this embodiment, three plane portions 114, 115 and 125 are provided.
The offshore wall surface 10 is constituted by two curved surfaces 141 and 142 which connect them so that the curvatures are continuous. Of these, the planes 114, 1
15, the upper surface of the curved surface 141 and the curved surface 142 forms the upper inclined surface 11, and the flat surface 125 and the curved surface 14 inclined to the land side.
The lower part of 2 forms the lower inclined surface 12.

As described above, even when most of the offshore wall surface 11 is constituted by a plurality of planes, the plurality of planes are connected by a curved surface so that the curvatures are continuous, so that the offshore side surface is connected. The wall surface 10 can be configured as a continuous curvature surface having no curvature and having a continuous curvature.

Fifth Embodiment (FIG. 6) In this embodiment, the lower inclined surface 12 is constituted by a plane 126. Even with such a configuration, the wavebreak structure main body 50 can be easily manufactured because the offshore flat surface 10 has a flat surface portion.

Sixth Embodiment (FIG. 7) In this embodiment, the upper inclined surface 11 is constituted by a flat surface 116. Even with such a configuration, the wave-breaking structure main body 50 can be easily manufactured because the offshore flat surface 10 has a flat portion as in the fifth embodiment.

Seventh Embodiment (FIG. 8) In this embodiment, a vertical plane portion 13 is provided between an upper inclined surface 11 and a lower inclined surface 12. As described above, the offshore wall surface 10 may have a vertical surface portion that is not inclined on any of the offshore side and the land side other than the upper inclined surface 11 and the lower inclined surface 12.

Eighth Embodiment (FIG. 9) In this embodiment, a convex portion 15 extending from the lower part of the lower inclined surface 12 to the lower side is formed on the offshore wall surface 10. In this way, the offshore wall surface 10 may have such a convex portion 15 that is partially directed to the offshore side. Even with such a configuration, this wave-breaking structure can be provided on the upper inclined surface 1.
1 provides excellent non-overtopping characteristics by repelling waves, and a wave pressure having a downward component force acts on the lower inclined surface 12, so that the wave-breaking structure body 50 is pushed upward. Vertical wave force can be reduced. Further, the offshore wall surface 10 is entirely a continuous curvature surface, and the upper part of the offshore wall surface 10 including the upper slope surface 11, specifically, the upper slope surface 11 and the lower slope surface 12
Since the portion excluding the convex portion 15 is configured such that the curvature gradually decreases toward the upper portion, particularly excellent non-overtopping characteristics can be obtained.

Such an embodiment is provided especially in a deep sea area or the like to prevent the lower slope 12 from protruding greatly to the offshore side, thereby preventing the volume of the breakwater structure 50 and the ground contact area from excessively increasing. Therefore, it is particularly preferable to provide it in a deep sea area or the like.

[0064]

As described above, according to the present invention, since the waves colliding with the offshore wall surface as a body of water are repelled offshore by the upper inclined surface provided above the offshore wall surface, the present invention is excellent. Non-overtopping characteristics can be obtained. In addition, the vertical upward component of the wave pressure acting on the upper inclined surface is offset by the vertical downward component component of the wave pressure acting on the lower inclined surface provided below the offshore wall. The vertical wave force acting to push the wave structure body upward is reduced. For this reason, it is possible to reduce the size and weight of the wavebreak structure main body while reducing the sliding and overturning of the wavebreak structure body, reduce the production and construction costs, and further reduce the necessary foundation to The cost and labor required for improvement can be reduced. Furthermore, since this lower inclined surface is inclined toward the land side, the contact area of the main body of the breakwater structure is increased,
High stability of the main body of the wave preventing structure can be obtained.

If the upper inclined surface that repels waves is provided in a region including the still water surface, most of the incoming waves can be received by the upper inclined surface, and the non-overtopping wave characteristics can be further improved. it can.

Further, if at least a part of the offshore wall surface is formed by a flat surface, the flat surface portion can be easily manufactured, so that the cost and time required for manufacturing the wavebreak structure can be reduced.

If the offshore wall is formed to have a concave shape facing offshore, or if it is formed as a continuous surface of curvature, the waves colliding with the offshore wall as a body of water move smoothly along the offshore wall. Then, it is rebounded offshore, so that even better non-overtopping characteristics can be obtained, and the impact and stress concentration on the offshore wall due to the water mass moving along the offshore wall can be reduced.

Further, if the offshore wall surface is configured so that the curvature gradually decreases toward the upper part, the wave pressure acting on the offshore wall surface gradually decreases toward the upper part of the offshore wall surface. The vertical wave force acting on the object body can be reduced.

[Brief description of the drawings]

FIG. 1 is an overall perspective view showing a first embodiment of a wavebreak structure according to the present invention.

FIG. 2 is a cross-sectional configuration diagram of the first embodiment (flare type with footing).

FIG. 3 is a sectional configuration diagram of the second embodiment.

FIG. 4 is a sectional configuration diagram of the third embodiment.

FIG. 5 is a sectional configuration diagram of the fourth embodiment.

FIG. 6 is a sectional configuration diagram of the fifth embodiment.

FIG. 7 is a sectional configuration diagram of the sixth embodiment.

FIG. 8 is a sectional configuration diagram of the seventh embodiment.

FIG. 9 is a sectional configuration diagram of the eighth embodiment.

FIG. 10 is an explanatory diagram of an experimental device for non-overtopping characteristics.

FIG. 11 is a cross-sectional comparison diagram of the offshore wall surface 10 of each model used in the experiment.

FIG. 12 is a graph showing experimental results of non-overtopping characteristics of each experimental model.

FIG. 13 is a graph showing an example of the results of measuring the wave pressure acting on the offshore wall surface 10 of each model.

FIG. 14 is a graph showing experimental results of vertical wave force acting on each model.

FIG. 15 is a cross-sectional configuration diagram showing a construction mode of a conventional breakwater structure (upright type).

FIG. 16 is a sectional view showing a conventional wavebreak structure (flare type).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Offshore wall surface 11 Upper inclined surface 12 Lower inclined surface 40 Foundation 50 Breakwater structure main body 60 Wave breaker

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Tomokazu Nakagawa 1-5-5 Takatsukadai, Nishi-ku, Kobe City Inside Kobe Research Institute, Kobe Steel Ltd. (72) Inventor Takehiro Nakaoka Takatsukadai, Nishi-ku, Kobe-shi 1-5-5 Kobe Steel, Ltd.Kobe Research Institute (72) Inventor Kenichi Sugii 1-3-1-18 Wakihamacho, Chuo-ku, Kobe Kobe Steel Ltd.Kobe Head Office (72) Inventor Hamasaki Yoshihiro 1-3-18 Wakihama-cho, Chuo-ku, Kobe Kobe Steel, Ltd. Kobe Head Office

Claims (8)

[Claims] 1. A wave-breaking structure erected facing offshore, wherein an upper inclined surface is provided at an upper part of an offshore wall surface so as to incline offshore so as to approach offshore. A wave-breaking structure, characterized in that a lower inclined surface is provided at a lower portion of a wall surface and is inclined toward a land side so as to approach an offshore side. 2. The offshore wall surface has a ratio D / D of a height B of the offshore wall surface and a horizontal length D of the upper inclined surface protruding.
The wavebreaking structure according to claim 1, wherein B is 0.2 or more and 1.5 or less. 3. The wavebreak structure according to claim 1, wherein the upper inclined surface is provided in a region including a still water level position. 4. The wavebreak structure according to claim 1, wherein at least a part of the offshore wall surface is formed by a flat surface. 5. The wavebreak structure according to claim 1, wherein the offshore wall surface has a shape that is concave toward the offshore as a whole. 6. The wavebreak structure according to claim 1, wherein an upper portion of the offshore wall surface including the upper inclined surface is formed as a continuous curvature surface having a continuous curvature. 7. The wavebreak structure according to claim 6, wherein the curvature continuous surface is formed over the entire offshore wall surface. 8. The wavebreak structure according to claim 6, wherein at least an upper portion of the curvature continuous surface is configured such that a curvature gradually decreases toward an upper portion.