JPH0921122A - Wave absorber - Google Patents

Abstract

(57) [Summary] [Purpose] Even if the water surface rises and falls due to tidal level fluctuations, it is possible to obtain the prescribed wave-dissipation effect at all times, and the flat plate does not resonate with the waves and move vertically, which is good. (EN) Provided is a wave-dissipating device capable of obtaining a proper wave-dissipating effect, and further preventing a water mass that has been broken into waves from passing behind the wave-exiting side of the device and returning it to the wave-entry side. [Structure] At least a part is formed of a member having a low specific gravity so that the overall specific gravity is less than 1, or both ends of plate bodies 10 and 20 which are provided with a buoyancy chamber so as to float above the water surface are reversed. The plate is bent in one direction, the one ends 10g and 20g of the plate are directed on the wave ingress side, and the other end 10f and 20f of the plate is arranged on the water surface so that the bending direction is toward the water bottom. The mooring means 11 and 12 are arranged so as to be vertically movable so that the bending direction is directed to the water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wave canceling technique for reducing the amplitude of waves.

[0002]

2. Description of the Related Art Conventionally, various wave absorbers have been proposed to secure safe port waters. These are generally wave-dissipating structures that have fixed or stacked structures and obstacles on the seabed.
As one of them, it has a structure in which the flat plate is fixed below the water surface at both ends by support columns fixed to the seabed, and the wave is broken by using the breaking wave generated when the water depth suddenly becomes shallow on the submerged flat plate. There is known a wave extinction device that dissipates and dissipates the energy of. However, in the case of this device, it is necessary to install a fixed plate near the water surface in order to try to cancel the wave by breaking the wave, but since the submerged depth fluctuates due to the tidal level fluctuation, a constant wave breaking effect cannot be obtained. was there.

In order to solve this disadvantage, for example, Japanese Patent Laid-Open No.
In JP-A-204515, a plate body is fixed by rotatably fixing a wave entry side end of the plate body and a seabed structure with a hinge, a buoyancy chamber is provided on a lower surface of the plate body, and air is injected into the buoyancy chamber. A movable swash plate breakwater has been proposed that keeps the seawater at a certain distance below the water surface and injects seawater into the room when the equipment is not in use to sink the entire equipment to the seabed. However, in this device, the water mass that has been broken wave passes behind the wave exit side of the device (shore side), and the plate body rotates up and down around the hinge part due to the wave, so the wave is generated behind the device. Stands,
There was a drawback that the wave-dissipating effect was reduced. In addition, since the plate is fixed to the hinge part, the submerged depth between the seabed structure and the hinge part increases at high tide in the sea area where the difference in ebb and flow is high, so the angle between the plate and the water surface suddenly increases. Therefore, there is a problem that the wave-dissipating effect decreases. At this time, if the length of the plate body is increased, the angle formed between the plate body and the water surface can be made a gentle slope, but this also causes the members other than the plate body to become large, and the entire device becomes oversized. There is a new problem of being lost.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to obtain a predetermined wave-dissipating effect even if the water level rises and falls due to tide level fluctuation. To provide a wave device.

Another object of the present invention is to provide a wave canceling device capable of reducing the vertical resonance of the flat plate due to waves and obtaining a good wave canceling effect.

A further object of the present invention is to provide a wave-eliminating device capable of preventing a water mass that has been broken by waves from passing behind the wave-exit side of the device and returning it to the wave-entry side.

[0007]

The present invention has been made in view of the above-mentioned object, and the gist thereof is to bend both ends of a plate body formed so as to float above the water surface in opposite directions. Arrange one end of the plate on the water surface so that the bending direction is toward the bottom of the water and the bending direction is toward the wave entry side (offshore side).
Further, there is provided a wave canceling device in which the other end of the plate member is directed to the wave exit side (shore side) and the bending direction thereof is directed to the water, and is vertically moored by a mooring means. In order to form the plate body so as to float above the water surface in the wave canceling device of the invention, at least a part of the plate body is formed of a member having a low specific gravity so that the specific gravity of the whole plate body is less than 1, or Alternatively, a buoyancy chamber can be provided in the plate body. Here, as the low specific gravity member forming at least a part of the plate body, a foamed resin body such as styrene foam or foamed urethane, FRP, reinforced plastic or a rubber material can be used. In addition, when forming a part of plate body with a low specific gravity member, a member with a low specific gravity is arrange | positioned so that the gravity center of the whole plate body may not be biased toward an edge part. When the plate body is provided with a buoyancy chamber, for example, an air chamber is formed on the entire surface of the plate body, or an air chamber is partially formed so that the center of gravity of the whole plate body is not biased toward the end. A buoyancy chamber may be formed by sealing a gas such as air in the air chamber.

The mooring means is fixed to the bottom of the water so as to lock the connecting member such as a cord, a chain, a wire rope or a synthetic fiber rope having one end locked to the plate and the other end of the connecting member. You may comprise with the anchor.

[0009]

In the wave canceling device of the present invention, when the height of the wave that has entered the plate is low, the wave breaks because the water depth sharply decreases due to the inclined surface of the plate end on the offshore side. This allows wave energy to be dissipated without being transmitted to the shore. Further, when the height of the wave is high, the wave enters the inclined surface of the end of the plate body on the offshore side, and the local water pressure pushes the end of the offshore side downward. On the other hand, since the shore-side end is bent in the opposite direction to the offshore-side end, it rises so as to be relatively flipped up and its inclination angle increases.
Therefore, the incoming waves are broken into water masses because the water depth suddenly becomes shallow due to the slope between the central part and the end on the shore side. Then, the water mass hits an end portion on the shore side protruding above the water surface and is blocked, and is reflected and flows offshore on the plate body or is guided in the lateral direction of the plate body. This allows
Wave energy can be dissipated without being transmitted to the shore of the plate. Also, in the above-mentioned wave-dissipating process, the plate moves up and down due to the force of the ingress wave and the weight of the water mass formed on the plate, and this up-and-down motion also absorbs part of the energy of the ingress wave. It

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a side view of the wave breaker of the present invention installed on the sea, and FIGS. 2 and 3 show perspective views of plates 10 and 20 used in the wave breaker of the present invention.
In FIG. 1, the wave-breaking device of the present invention includes a plate body 10, and a cord body 11 and an anchor 12 as mooring means for mooring the plate body 10 at a predetermined position on the water surface as main parts.

As shown in FIG. 2, the plate body 10 is formed so that a central portion 10b and both end portions 10a and 10c thereof have a rectangular plane as a whole, and the end portion 10a is a side 10d and is directed upward in the drawing. The end portion 10c is bent at an angle α = 120 ° and the end portion 10c is a side 10e, and the angle β = 120 is set downward.
It is formed so that it bends about a degree.

Here, the length ratio of the end portion 10a, the central portion 10b and the end portion 10c is set to approximately 1: 1: 1 as shown in FIG. 1 or a: b: c = 1 as shown in FIG. : 2: 1 or other ratio can be set appropriately. That is, the end portion 10c may be bent at a length and an angle such that the incoming wave can be guided to the upper surface of the plate body, and the end portion 10c allows the wave or water mass that has entered the plate body to go behind it. (Shore side)
It suffices if it is bent at such a length and angle that it will not pass through. Further, in order to form the plate body 10 so as to float above the water surface, for example, a foamed resin body such as foamed urethane is formed in a plate shape and reinforcing bars such as reinforcing bars are arranged inside the foamed resin body. The entire surface may be covered with a thin steel plate so that the specific gravity of the whole plate body is less than 1. Alternatively, the reinforced concrete having an air chamber (buoyancy chamber) may have a specific gravity of less than 1. Furthermore, the central portion 10b in FIG. 2 may be formed in a shape other than a flat plate, for example, bent at one or more sides parallel to the sides 10d and 10e. Furthermore, the planar shape of the plate body 10 is not limited to the above rectangle,
For example, it may be oval or polygonal.

The end portion 10c of the plate body 10 is directed to the wave entry side, that is, offshore, and the bending direction is the seabed 13.
On the other hand, the end portion 10c is arranged so that the end portion 10c faces the exit side of the wave, that is, the shore, and the bending direction of the end portion 10c faces the sea. When the one end of the cord body 11 is locked and the other end of the cord body 11 is locked to the anchor 12 fixed to the seabed 13, the wave breaking device of the present invention can be formed. Here, in order to allow the plate body 10 to freely move up and down, the cord body 11 is provided with a length that causes slack.

In the wave canceling device of the present invention, the plate 10 is
Alternatively, as shown in FIGS. 3 (a) and 3 (b), a plate body 20 having a curved surface as a whole may be used. That is, the plate 20
Is integrally formed with a curved surface 20a whose center is convexly curved downward and a curved surface 20c whose center is convexly curved upward so that the cross-sectional shape becomes an S-shape as shown in FIG. 3 (b). . Here, the plate body 20 is formed so as to float on the water surface similarly to the plate body 10, and is arranged so that the end side 20g is directed to the wave entry side, that is, offshore, and the bending direction is directed to the seabed 13, On the other hand, it is arranged so that the end side 20f faces the exit side of the wave, that is, the shore, and the bending direction is directed to the sea,
Similar to the plate body 10, it is moored on the sea by the cord body 11 and the anchor 12.

Next, with reference to FIGS. 4 and 5, the wave breaking process of the wave breaking device will be described. When the height of the wave is low, the wave entering the plate body 10 floating above the sea as shown in FIG. 4 is broken because the water depth suddenly becomes shallow due to the inclined surface of the end portion 10c. , Wave energy can be dissipated without being transmitted to the shore.

When the height of the wave is high, as shown in FIG. 5, the wave 21 enters the inclined surface of the shore side end portion 10c of the plate body 10 and the end portion 10c is moved downward by the local water pressure. Push down. On the other hand, the end 10a on the shore is the end 1 on the offshore side.
Since it bends in the opposite direction of 0c, it rises so as to be relatively flipped up and its inclination angle increases. for that reason,
The waves that have entered are especially in the central portion 10b and the end portion 10 on the shore side.
Because the water depth suddenly becomes shallow due to the inclination with a, it breaks,
It becomes a water mass. Then, the water mass hits the shore-side end portion 10a protruding above the water surface and is blocked, and is reflected and flows on the plate body 10 to the offshore side or is guided in the lateral direction of the plate body 10. Thereby, the wave energy can be dissipated without being transmitted to the shore of the plate body 10. In the wave-dissipating process, the plate body 10 moves up and down in the vertical direction (arrow direction in FIG. 5) due to the force of the incoming wave and the pressure of the water mass formed on the plate body 10. Part of the energy of the incoming wave is converted into. The plate body 20 of FIG.
The wave-dissipating device using the same can similarly act to break the incoming wave.

[0017]

According to the wave-eliminating device of the present invention, the plate body is formed so as to float above the water surface, and is moored by the mooring means so that it can be moved up and down. The wave effect can be obtained. In addition, since the wave entrance side end of the plate bends toward the water bottom and the wave exit side end bends upward, even if a wave enters and a water mass forms on the plate, the plate Since the end of the body on the wave exit side (shore side) rises so as to be flipped up, it is possible to reduce the resonance of the plate body in the vertical direction due to waves and obtain a good wave-dissipating effect.
Furthermore, because the end of the plate on the wave exit side is steep, it prevents the lump of water from passing behind the wave exit side of the device.
It can be returned to the wave entry side (offshore side).

[Brief description of drawings]

FIG. 1 is a side view of a wave canceling device of the present invention in a use state.

FIG. 2 is a perspective view of a plate used in the wave canceling device of the present invention.

3A is a perspective view of a plate different from FIG. 2, and FIG.
FIG. 3A is a sectional view taken along the alternate long and short dash line IIIb-IIIb in (a).

FIG. 4 is a side view showing a movement of a device of the present invention when weak waves enter, with a part of the device omitted for convenience of display.

FIG. 5 is a side view showing the movement of a device of the present invention when strong waves enter, with a part of the device omitted for convenience of display.

[Explanation of symbols]

 10 Plates 11 Cords (Mooring Means) 12 Anchors (Mooring Means) 13 Seabed 20 Plates

Claims (2)

[Claims] 1. A plate body which is formed so as to float above the water surface is bent at opposite ends in opposite directions, and one end of the plate body is directed toward the wave entrance side and the bending direction is directed toward the bottom of the water surface. A wave-dissipating device which is arranged so that the other end of the plate body is directed to the wave exit side and the bending direction of the plate body is above the water, and is moored vertically by a mooring means. 2. The plate body is formed with at least a part of a member having a low specific gravity so that the specific gravity of the whole plate body is less than 1, or the plate body is provided with a buoyancy chamber to float the plate body on the water surface. The wave breaking device according to claim 1, wherein