JP2768268B2 - Wave-dissipating structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wave-breaking structure for the purpose of creating a calm sea area for recreation, protecting port facilities and the like, and mitigating wave power and overtopping on the open sea such as offshore artificial islands. is there.

[0002]

SUMMARY OF THE INVENTION
Instead of the conventional single-plate type submerged horizontal plate or wave-breaking structure using a submerged inclined plate, the three submerged horizontal plates are stepped, and the submerged horizontal plate on the offshore side has a large submerged depth, shoreside We proposed a wave-dissipating structure with small and large arrangements. (JP-A-4-289310
No.) This wave-dissipating structure has better wave-dissipating performance as compared with the conventional single-plate type submerged horizontal plate or submerged inclined plate, and can disperse and reduce the wave force acting on the structure body. In addition, the shape is simple and the workability is excellent.

[0003] However, the wave-dissipating structure using the three staircase-type immersed horizontal plates can sufficiently exhibit its wave-dissipating ability in the sea area where the tide level difference is about 2 m, but the tide level at which the tide level difference becomes about 3 m. In the sea area with a large difference, it was difficult to fully demonstrate its wave-dissipating ability. That is, in the sea area where the tide level difference is large and is about 3 m, even at the time of high tide or average tide, the relatively low wave having a maximum wave height of about 2 m passes through even if three stair-type immersed horizontal plates are used, and the transmitted wave height is 50 cm or less. And it was difficult.

The present invention has been made in view of the above circumstances, and an object thereof is to efficiently break a wave having a wave height of about 2 m and a maximum period of about 8 seconds even in a sea area having a large tide level difference of about 3 m. The idea is to propose a wave-breaking structure.

[0005]

According to a first aspect of the present invention, there is provided a wave-absorbing structure comprising four submerged horizontal plates, the submerged depth of which is the largest at the most offshore side (the first one) and the most submerged side (the fourth one). ) Is minimized, and the fourth submerged horizontal plate is located at a position 1.5 to 2.5 m above the low tide water level.

According to a second aspect of the present invention, the four submerged horizontal plates are arranged such that the submerged depth is the largest at the most offshore side (first sheet) and the least at the most shore side (fourth sheet). It is arranged in a staircase type, and the fourth immersed horizontal plate is located at a position where the offshore side is low and the shore side is inclined high, and diagonally between the low tide water level and the high tide water level. Features.

According to a third aspect of the present invention, there is provided the wave absorbing structure according to the first aspect, wherein a projecting ridge substantially parallel to the shore line is provided on a flat surface of the fourth submerged horizontal plate. Features.

[0008]

FIG. 1 shows an example of a wave-dissipating structure according to the first aspect of the present invention.
Four immersed horizontal plates 1-1, 1-2, 1-3 with a thickness of 70 cm
1-4 are arranged in a staircase shape. The upper surface of the immersion horizontal plate 1-4 on the shore side (fourth sheet) is 2 m from the low tide water level (LWL).
The upper surface of the third submerged horizontal plate 1-3 is located 0.3 m above the low tide water level, and the virtual average gradient α indicated by the line connecting the centers of gravity of the four submerged horizontal plates is 9. 6 °.

The EL in the drawings is L.R. W. The height of the upper surface of the immersed horizontal plate with reference to L.

In the wave-dissipating structure of this embodiment, the fourth submerged horizontal plate is 2 m higher than the low tide water level, and even at high tide water level, the immersion depth is less than the tide level difference, and even in sea areas with a tide level difference of about 3 m, it is about 1 m Therefore, a wave having an incident wave height of about 1 m is broken on the immersed horizontal plate 1-4, and a desired wave-eliminating action is exhibited.

Even when the incident wave height is as low as 1 m or less, the breaking wave is promoted by the collision of the return flow on the submerged horizontal plate generated by hitting a plurality of edges of the stepped submerged horizontal plate or the disturbance of the return flow in the gap. Is done.

FIG. 2 shows an example of the wave-dissipating structure according to claim 2, wherein four submerged horizontal plates 1-1, 1-2, 1-3, and 1 are located in a sea area with a tide level difference of 2.83 m. -5 is arranged in a step shape. The immersion depth of this submerged horizontal plate is large on the offshore side and small on the shore side, and the submerged horizontal plate 1-5 on the most shore side (fourth sheet) has a high tide water level (HWL) on the upper surface of the shore side. The offshore side is inclined at a position lower than the shoreside, and the upper surface of the offshore side is the height of the low tide water level (LWL). The immersion depth of the third submerged horizontal plate 1-3 is set at the low tide water level, and the three submerged horizontal plates 1-3
The virtual average gradient α connecting the centers of gravity of 1, 1-2 and 1-3 is 8 °
It has become.

In this structure, since the submerged horizontal plate 1-5 on the most shore side (fourth sheet) is inclined between the high tide and the low tide water level, wave breaking occurs on the inclined surface even at high tide, and at high tide or on average. Waves with a wave height of about 50 to 100 cm do not pass through at tide.

FIG. 3 shows an example of the wave-dissipating structure according to claim 3, wherein four submerged horizontal plates 1-1, 1-2, 1-3 and 1 are provided in a sea area with a tide level difference of 2.83 m. -6 is arranged in a staircase shape. The depth of the submerged horizontal plate is large on the offshore side and small on the shore side. The upper surface of the submerged horizontal plate 1-6 on the most shore side is located 1.7m higher than the low tide water level (LWL). Has a low tide water level, and the virtual average gradient α is 8 °. In addition, the submerged horizontal plate 1-6 on the most shore side (fourth sheet)
On the lower surface, a ridge 2 substantially parallel to the shore line is provided at the center in the width direction.

In this structure, the fourth submerged horizontal plate 1-6 has a submersion depth of about 1 m even at high tide, and has a ridge on its lower surface. Waves are broken at -6 and reflected by the ridges 2 to block the passage.

In this embodiment, the ridge 2 is provided on the lower surface of the immersed horizontal plate 1-6, but it may be provided on the upper surface or both upper and lower surfaces.
Further, a ridge 2 is provided along the offshore side of the lower surface, or a ridge 2 is provided between the upper surface of the shore side of the immersion horizontal plate 1-3 adjacent to the lower surface of the offshore side. 6, 1-3 may be connected.

The height of the upper surface of the fourth submerged horizontal plate in the sea area with a large tide level difference of about 3 m is the low tide water level +1.5 to
The height of the upper surface of the third immersed horizontal plate is preferably about ± 0.5 m at low tide water level.

[0018]

The wave-absorbing structure has the above construction. This structure has four submerged horizontal plates deep offshore,
The shore side is shallow and stair-shaped and arranged as described above, compared to the conventional single-plate type submerged horizontal plate or submerged inclined plate, the size of the breaking wave is large, the energy dissipation effect is high, and An effect and an effect such as a wave force acting on the structure can be dispersed and reduced.

At the same time, by arranging the submerged horizontal plate on the most shore side (fourth sheet) at a position 1.5 to 2.5 m higher than the low tide water level, even at high tide in a sea area with a tide level difference of about 3 m, Waves with a low wave height of about 2 m can be broken by a horizontal plate immersed on the shore, and the transmitted wave height can be reduced to 50 cm or less.

In the wave-absorbing structure according to the second and third aspects, the sloping horizontal plate on the most shore side (fourth) is inclined, or a ridge is provided on the flat surface, so that the breaking of the wave having a lower wave height can be reduced. It is reflected at the same time as it is promoted or at the same time, the passage is prevented, and the breaking ability is enhanced.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a wave-absorbing structure according to claim 1;

FIG. 2 is an explanatory view of a wave-absorbing structure according to claim 2;

FIG. 3 is an explanatory view of a wave-absorbing structure according to claim 3;

[Explanation of symbols]

1-1, 1-2, 1-3, 1-4, 1-5, 1-6 ...
Submerged horizontal plate, 2 ... ridge

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Kozo Bando 2-191 Tobita-Shi, Chofu-shi, Tokyo Kashima Construction Co., Ltd. (72) Inventor Yoshinobu Akiyama 2--19, Tobita-Shi, Chofu-shi, Tokyo No. 1 Kashima Construction Co., Ltd. Technical Research Institute (72) Inventor Hiromi Shinbo 2-19-1, Tobita-Shi, Chofu-shi, Tokyo Kashima Construction Co., Ltd. Technical Research Institute (56) References JP-A-4-289310 (JP, A) Hikaru Hira 4-82023 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) E02B 3/06

Claims (3)

(57) [Claims] 1. Four submerged horizontal plates are arranged in a staircase shape so that the depth of submersion is maximum on the most offshore side (first) and minimum on the most shore side (fourth), and The fourth submerged horizontal plate is a wave-dissipating structure in a sea area having a large tidal difference, wherein the upper surface thereof is located at a position 1.5 to 2.5 m higher than the low tide water level. 2. The four immersed horizontal plates are arranged in a staircase such that the depth of immersion is maximum on the most offshore side (first sheet) and minimum on the most shore side (fourth sheet), and The fourth submerged horizontal plate is located at a position where the offshore side is low and the shore side is inclined high, and is located at a position where the low tide water level and the high tide water level are diagonally separated. Wave-dissipating structure. 3. The wave-dissipating structure according to claim 1, wherein a ridge substantially parallel to the shoreline is provided on the flat surface of the fourth submerged horizontal plate.