JPH083456Y2 - Floating breakwater - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a floating breakwater that is suitable for caissons, marine farms and the like and that can calm waves and allow ocean currents to pass through.

[Conventional technology]

Conventionally, as a floating breakwater, for example, as shown in the cross-sectional view of FIG. 7, a flat cuboid pontoon 01 is moored to the seabed GL via a mooring chain 02 in the sea area between the ikesu and the offshore area. Things are known.

In this type of floating breakwater, the width B is suppressed from the economical point of view, and generally the incident wavelength λ / floating breakwater width B is about 4, and the transmitted wave height H _o / incident wave height H _i is It is about 0.5. Here, 03 is an incident wave and 04 is a transmitted wave.

However, such a structure has the following drawbacks.

(1) When the wavelength λ becomes longer, the motion of wave particles exists deep below the sea level WL, so the pontoon 01 near the sea level WL.
Even if the wave is floated, the motion of the wave particles almost completely penetrates backward, and as a result, the wave-dissipating action sharply decreases as shown by the chain line in FIG.

(2) If pontoon 01 is synchronized with the motion of wave particles,
You cannot expect a wave-dissipating effect at all.

[Problems to be solved by the device]

The present invention has been proposed in view of such circumstances, and an object thereof is to provide an economical floating breakwater having a wave-dissipating action even for an incident wave having a relatively long wavelength.

[Means for solving the problem]

To this end, the present invention comprises a pair of front and rear vertical side plates, a pair of front and rear upper inclined side plates, and a pair of front and rear lower inclined side plates, each of which has its upper and lower surfaces opened and its left and right ends closed by end walls. Horizontal horizontal octagonal tubular long floating body moored to the water surface by multiple chains separated by multiple intermediate walls at appropriate intervals and anchored to the seabed, and along the vertical center vertical plane of the long floating body. A lower vertical plate vertically extending over the entire length thereof, a weight disposed on the lower vertical plate, and a pair of front and rear horizontal overhanging plates which are protruded inside each of the vertical side plates so as to face each other. It is characterized by having.

[Action]

Since the lower vertical plate is hung from the buoyant body, it is possible to reflect wave particles of an incident wave having a short wavelength. Further, since a weight is attached to the lower end of the lower vertical plate, the center of gravity of the floating breakwater is lowered, and it is difficult for the floating breakwater to sway. Furthermore, since a water tank that communicates with the surrounding seawater through the opening on the bottom is formed inside the floating breakwater, the seawater inside moves into and out of the water tank against the ups and downs of the floating breakwater, which creates resistance to the floating water. The bank is less likely to sway.

And, since a weight is attached to the lower end of the lower vertical plate, the vertical shaking natural period of the floating breakwater becomes long,
It becomes easy for the floating breakwater to tune in a reverse phase to a wave having a relatively long wavelength and a high wave height, and at that time, a large wave breaking action can be obtained. In addition, since the cross-sectional shape of the buoyant body is an octagon with a horizontal apex, when the incident wave height is high, the restoring force at the top and bottom is reduced, the natural period of up and down swing becomes a little longer, and the floating wave breaks up. It becomes easy to tune to a wave having a relatively long wavelength in antiphase, and then a large wave-dissipating effect can be obtained. Further, since horizontal overhanging plates are provided so as to be opposed to each other on the inner sides of both the vertical side plates, slotting of seawater occurs there, and the energy of the incident wave can be diffused.

〔Example〕

An embodiment of the present invention will be described with reference to the drawings. The same reference numerals as those in FIG. 7 denote the same members as those in the same drawing. First, in FIG. 1 perspective view, 1 has a horizontal top side and a horizontal bottom side. A buoyant body having a flat octagonal left end wall 2 and a right end wall 3, 4,5, 6 are vertical side plates of buoyant body 1, upper swash plate, lower swash plate, and 7 partition the inside of the buoyant body at appropriate intervals It is a plurality of intermediate walls.

Reference numeral 8 denotes a lower vertical plate whose upper end is vertically erected on the lower end of the buoyancy body 1 along the vertical center vertical plane over its entire length and has an inverted T-shaped cross section, and 9 is provided at the lower end of the lower vertical plate 8. The dead weight,
Its weight is adjusted so that the sea level WL comes to an intermediate level of the buoyancy body 1.

Next, in the transverse sectional view of FIG.
A pair of left and right horizontal overhanging plates which horizontally and oppositely project from the lower end of the buoyancy body 1 toward the inside of the buoyancy body, 11 are buoyancy members attached to the inner surfaces of the side walls and have an appropriate thickness t, and 12 and 13 are respectively The top surface opening and bottom surface opening 14 provided at the top and bottom positions of the buoyancy body 1 are water tanks formed inside the buoyancy body 1.

In such a structure, when the wavelength λ of the incident wave 03 is short, the motion of the wave particles decreases sharply as it goes below the sea surface WL, so that the action of the lower vertical plate 8 of the buoyant body 1 allows the wave particles to move freely. The movement is restricted so that it does not pass through the floating breakwater, the center of gravity of the floating breakwater is further lowered by the action of the weight 9, and the water tank 14 is provided in the buoyancy body 1. Does not move.

When the wavelength λ of the incident wave 03 is intermediate, the buoyant body 1 and the incident wave 03 move relative to each other. Therefore, as shown in the transverse sectional view of FIG. 3, when the wave height is low, the lower vertical plate 8 This increases the vertical additional mass and adjusts the vertical swinging natural period of the floating breakwater to be longer, so that it is tuned in antiphase with the incident wave 03 with the longest possible cycle. The wave created by the movement of the object and the incident wave 03 cancel each other, and the seawater can enter and exit the water tank 14 through the bottom opening 13 to provide a damping force against vertical shaking.

Further, as shown in the horizontal cross-sectional view of FIG. 4, when the wave height is high, in addition to the action described in FIG. 3, since the horizontal cross-section of the buoyancy body 1 is octagonal, the water line width is not constant in the vertical direction. Since the sea level WL becomes small in the range where it is applied to the upper swash plate 5 or the lower swash plate 6, the stability of the upper and lower swash plates decreases on average, and the natural period of vertical swing becomes a little longer. It is possible to shift the wave-dissipating effect by tuning in the opposite phase to the longer wavelength side.

Further, since the water tank 14 is provided with the horizontal overhanging plate 10, as shown in the transverse sectional view of FIG. 5, the slotting 15 is generated in the water tank, and the energy of the incident wave 03 is dissipated there, and the floating wave of the floating wave The energy of the waves propagating backward can be reduced.

As a result of a model test of such a floating breakwater,
As shown by the solid line in the diagram, the wave-dissipation performance is greatly improved in the medium incident wave wavelength range compared to the known pontoon-type floating wave breakwater, and in particular the slotting tuning point It has been found that the swing tuning point has a particularly remarkable wave-dissipation performance. The horizontal overhanging plate 10 may be attached to the lower vertical plate 8 near the upper end thereof.

 With such a structure, the following effects can be obtained.

(1) Since the lower vertical plate is provided, the wave particles can be reflected when the wavelength of the incident wave is short, so that the wave breaking capability of the floating breakwater is improved within a limited range.

(2) Since the weight is attached to the lower vertical plate, the center of gravity of the floating breakwater is lowered, and thus the floating breakwater itself is less likely to be swept.

(3) Since the water tank that communicates with the surrounding seawater through the bottom opening is formed in the buoyant body, the seawater inside moves into and out of the water tank against the ups and downs of the floating breakwater, and thus the floating breakwater is It becomes difficult to shake.

(4) Since a weight is attached to the lower vertical plate, when the wave height of the incident wave is high, the up-and-down natural period of the floating breakwater becomes long, so that the floating wave breaks up as long as possible. It becomes possible to obtain a significant wave-dissipating effect in the range where the wave height of the incident wave is relatively high.

(5) Since the upper swash plate and the lower swash plate are connected to the upper and lower sides of the vertical side plate, respectively, when the wave height of the incident wave is high,
The stability of the lower part is reduced, and the natural period of up and down shaking becomes a little longer. Therefore, the same effect as (4) above can be obtained.

(6) Since the horizontal overhanging plates are provided so as to project inside the vertical side plates, respectively, sloshing of seawater can be caused to dissipate the energy of the incident wave, thus providing a large wave-dissipating effect.

[Effect of device]

In short, according to the present invention, a pair of front and rear vertical side plates, a pair of front and rear upper sloping side plates and a pair of front and rear lower sloping side plates have upper and lower surfaces opened respectively, and left and right ends are closed by end walls and an inner portion is formed. Is a horizontal octagonal tubular long floating body that is partitioned by a plurality of intermediate walls at appropriate intervals and floated and moored on the water surface by a plurality of chains anchored to the seabed, and along the vertical center vertical plane of the long floating body. Lower vertical plate vertically extending over its entire length, a weight provided on the lower vertical plate, and a pair of front and rear horizontal overhanging plates that are opposed to each other inside the vertical side plates. Since the present invention provides an economical floating breakwater having a wave-dissipating action even for an incident wave having a relatively long wavelength, the present invention is extremely useful industrially.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG.
Fig. 2 is a cross-sectional view taken along line II-II, Fig. 3 and Fig. 4 are similar cross-sectional views showing the wavefront relative motion range when the wave height of the floating breakwater of Fig. 2 is low and high, respectively. FIG. 5 is a transverse cross-sectional view showing a state where the seawater in the water tank of the floating breakwater of FIG. 2 is slotted, and FIG. 6 is a diagram showing the breaking water performance of the floating breakwater of the present invention. FIG. 7 is a cross-sectional view showing a known pontoon type floating breakwater. 1 ... Buoyant body, 2 ... Left end wall, 3 ... Right end wall, 4 ... Vertical side plate, 5 ... Upper swash plate, 6 ... Lower swash plate, 7 ... Middle wall, 8 ... Bottom vertical Plate, 9 ... Weight, 10 ... Horizontal overhanging plate, 11 ... Buoyant material, 12 ... Top opening, 13 ... Bottom opening,
14 ... water tank, 15 ... slotting, 02 ... mooring chain, 03 ... incident wave, H ... wavefront relative motion range, t ... thickness,

Claims (1)

[Scope of utility model registration request] 1. A pair of front and rear vertical side plates, a pair of front and rear upper sloping side plates and a pair of front and rear lower sloping side plates each having upper and lower surfaces opened and left and right ends closed by end walls, and the inside is appropriately formed. A horizontal octagonal tubular long floating body in the left-right direction that is moored to the surface of the water by a plurality of chains that are separated by a plurality of intermediate walls and anchored to the sea floor, and that along the vertical center vertical plane of the long floating body. A lower vertical plate vertically extending over the entire length, a weight disposed on the lower vertical plate, and a pair of front and rear horizontal overhanging plates that are opposed to each other inside the vertical side plates. Floating breakwater that is equipped with.