JPH0757938B2 - Submarine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a submerged dike, which is a type of wave-dissipating structure.

<Prior art> It is necessary to calm the coastal area in order to preserve the eroding coast, develop a marine recreation area, and develop aquatic areas such as aquaculture and marine farms. A submerged dike is conventionally used as one of the wave-dissipating structures used in such a case.

The submerged levee is a levee body in which the entire structure is submerged below the seawater level, and is installed on the coast where the above-mentioned tranquilization is required.

<Problems to be Solved by the Present Invention> The conventional submerged dike described above has the following problems.

<A> Generally, after the incident wave is broken by the submerged dike, it falls into a water mass at the end of the submerged dike, which causes a new wave on the shore side, increasing the transmitted wave height and extinguishing the wave. It causes a decrease in the effect.

<B> In deep water, the depth of submersion at the top of the submerged dike becomes deeper, which causes a reduction in the wave-dissipating effect.

<Purpose of the present invention> Since the present invention has been made to solve the above problems, it is possible to surely improve the wave-dissipating effect and economically realize the wave-dissipating effect as compared with the conventional type. The purpose is to provide a possible submerged dike.

<Structure of the Present Invention> An embodiment of the present invention will be described below with reference to the drawings.

<B> Structure of submerged dike (Figs. 1 and 2) The submerged dike 1 of the present invention includes a top plate 11 made of concrete or the like.
And a side plate 14 and a bottom plate 16, which are formed into a hollow box shape.

(1) Top plate The top plate 11 is a plate that is attached to the upper surface of the submerged dike 1 with an inclination, and a water mass inlet 12 is opened at the top of the inclination.

The inclination angle of the top plate 11 and the opening area of the water mass inlet 12 are
Select at any time depending on the installation location and desired wave-eliminating effect.

Protrusions 13 are provided on the outer surface of the top plate 11 in order to impart roughness for promoting wave breaking.

It is conceivable that the protrusion 13 is provided with, for example, a band-shaped body in a direction orthogonal to the traveling direction of the incident wave.

(2) Side plate The side plate 14 is a plurality of plates connected to each side of the top plate 11, and integrally forms the side surface of the box-shaped submerged bank 1.

Of the side plates 14, the side plate connected to the uppermost side of the top plate 11.
Since the height of 14 is equal to the height of the submerged dike 1, select the height according to the water depth of the installation site.

In addition, the side plate 14 connected to the lowermost side of the top plate 11 has a return port.
Open 15

(3) Bottom Plate The bottom plate 16 is a plate connected to each bottom of the side plate 14 and constitutes the bottom surface of the box-shaped submerged bank 1.

As described above, the box-shaped submerged dike 1 which is closed except for the openings of the water mass inlet 12 and the return port 15 is formed.

<B> Installation of submerged dike (Figs. 1 and 2) A rock or the like is fixed with a net on the seabed at a predetermined installation place of the submerged dike 1 to construct a stable foundation ground 2 having a horizontal plane.

Then, the submerged embankment 1 configured as described above is installed on the foundation ground 2.

At this time, the side plate 14 having the return port 15 is installed so that the direction of the side plate 14 is orthogonal to the incident direction of the incident wave indicated by the arrow A.

Inside the submerged dam 1, up to the height of the lower end of the opening of the return port 15,
It is desirable to stack rocks 3, etc.

<Principle of Wave Dissipation of the Present Invention> The submerged dam 1 of the present invention performs wave extinction according to the following wave extinction principle.

<B> Reflected Wave The present invention is a submerged dike whose entire structure is submerged below the water surface.

Therefore, since the structure is based on the assumption that the incident wave is transmitted to some extent, the reflected wave height shown by the arrow B is always small as compared with the breakwater whose upper part is exposed from the water surface.

That is, the reflected wave is reduced by transmitting the incident wave.

However, according to the present invention, the transmitted wave (indicated by arrow C) is transmitted.
Can be dissipated by the following principle.

<B> Transmitted wave The transmitted wave is extinguished by the following two principles.

(1) Dissipation by forced breaking wave Part of the energy of the incident wave reaching the submerged dike 1 is reflected offshore by the reflected wave as described above, but the rest of the energy exceeds the submerged dike 1 above the shore. Is transmitted to the side as a transmitted wave.

The top plate 11 is inclined upward toward the shore and has a structure capable of concentrating wave energy.

The energy-concentrated wave cannot maintain a stable shape and is forcibly broken.

Breaking waves can be further promoted depending on the surface roughness of the projections 13 and the like on the top plate 11.

In this way, the wave dissipates energy according to the principle of forced breaking wave, so the energy transmitted to the shore is less than the energy of the wave riding on the submerged bank 1.

That is, the transmitted wave height can be reduced.

(2) Wave Dissipation at the Inlet of Water Mass In general, after the incident wave is broken by the submerged dam 1, it falls into a water mass W at the end of the submerged dam 1, which causes new waves on the shore. This is a cause of increasing the transmitted wave height and reducing the wave-dissipating effect.

Therefore, as shown in FIG. 2, the submerged dam 1 of the present invention takes in a part of this water mass W through the water mass inlet 12, passes through the submerged dam 1, and returns it as a return flow indicated by arrow D. It was constructed so that it could flow back from the outlet 15 to the offshore side.

Therefore, it is possible to mitigate the generation of new waves due to the water mass W falling on the shore.

That is, the energy transmitted to the shore can be reduced, and the transmitted wave height can be further reduced in addition to the effect of the above-mentioned wave breaking.

It should be noted that FIG. 3 shows the experimental results for obtaining the wave-dissipating effect, which were carried out using the model of the submerged dike 1.

According to this, in the vicinity of the arrow E, the transmitted wave height transmitted to the shore side is 60% or less of the incident wave height, with the width of the submerged dam 1 being about 1/4 of the wavelength of the wave to be extinguished, Also, it can be seen that the reflected wave height reflected offshore can be reduced to 40% or less of the incident wave height.

<Effects of the Present Invention> Since the present invention has been described above, the following effects can be expected.

<A> Generally, in a conventional submerged dike, after the incident wave is broken by the submerged dike, it falls into a water mass at the end of the submerged dike, which causes a new wave on the shore side and the transmitted wave height. Increase
It causes a decrease in the wave-dissipating effect.

However, the submerged dam of the present invention is configured such that a part of the water mass is taken in by the water mass inlet provided on the top plate, passed through the submerged dam, and can be returned to the offshore side from the return port opened on the side plate.

That is, since it is possible to mitigate the generation of a new wave due to the water mass falling on the shore, it is possible to reduce the energy transmitted to the shore and reduce the transmitted wave height.

Therefore, the wave-dissipating effect can be improved.

<B> Part of the energy of the incident wave reaching the submerged dike is reflected offshore by the reflected wave, but the remaining energy is transmitted as a transmitted wave to the shore beyond the upper part of the submerged dike.

The top plate of the present invention is inclined upward toward the shore and has a structure capable of concentrating wave energy.

That is, the wave in which the energy is concentrated cannot maintain a stable shape and is forcibly broken.

Therefore, the energy of the waves can be dissipated, and the energy transmitted to the shore can be reduced as compared with the energy of the waves riding on the submerged dike.

Therefore, the transmitted wave height can be reduced and the wave-dissipating effect can be improved.

<C> Depending on the surface roughness of the protrusions on the top plate,
The wave breaking effect can be enhanced by further promoting the wave breaking.

<D> The present invention is a submerged dike whose entire structure is submerged.

Therefore, the reflected wave height of the wave offshore is very small compared to the breakwater whose upper part is exposed from the water surface.

Therefore, unlike the conventional breakwater, overlapping waves due to reflected waves do not occur, so that there is no adverse effect on ships traveling in the vicinity.

<E> In the conventional submerged dike, the submerged depth of the top of the submerged dike becomes deeper in deep water, which causes a reduction in the wave-dissipating effect.

However, in the submerged bank of the present invention, the transmitted wave and the reflected wave can be effectively canceled.

Therefore, even if the submerged depth of the top of the submerged dip becomes deep, the wave-dissipating effect can be sufficiently obtained.

<F> Since the submerged dike of the present invention has low wave transmittance and reflectance, it is difficult to extinguish a wave with a long period.
A high wave-dissipating effect can be obtained.

<G> Since a box-shaped submerged embankment is used, the structure of the submerged embankment can be small.

Therefore, even when a submerged dike is installed in the deep water area, it can be economically constructed.

<H> Since the entire structure is a submerged dike that is submerged below the surface of the water, it does not damage the scenery near the coast.

<R> Since the incident waves are transmitted to the bank side of the submerged dike, fresh seawater constantly flows into the bank side of the submerged dike.

Therefore, the water quality on the bank side will be preserved.

<Nu> Breaking by wave breaking promotes the aeration effect and cleans the water on the shore.

<Le> According to the results of experiments conducted to obtain the wave-dissipating effect using a model of the submerged dike, the width of the submerged dike is about a quarter of the wavelength of the wave to be extinguished, and It can be seen that the transmitted wave height transmitted can be reduced to 60% or less of the incident wave height, and the reflected wave height reflected offshore can be reduced to 40% or less of the incident wave height.

Therefore, it is possible to obtain sufficient wave-dissipating effect with a small submerged dike.

Therefore, the wave can be economically dissipated.

[Brief description of drawings]

 FIG. 1: Cut perspective view of a submerged dike of the present invention FIG. 2: Side view cut of a submerged dike of the present invention FIG. 3: Table showing experimental results

 ─────────────────────────────────────────────────── ─── Continuation of the front page (71) Applicant 999999999 Matagumi Co., Ltd. 2-5-8 Kita-Aoyama, Minato-ku, Tokyo (72) Inventor Takaaki Uta 1-405-101 (72) Inventor Sakuramura, Shinji-gun, Ibaraki Satomi Murai 1-205-202 Kasuga, Yatabe-cho, Tsukuba-gun, Ibaraki Prefecture (72) Inventor Go Tanaka 3-7-3 Kichijoji-kitamachi, Musashino-shi, Tokyo (72) Hidehiro Katsui 6-Shimoda-cho, Kohoku-ku, Yokohama-shi, Kanagawa 31 (72) Inventor Kenji Nakatsuka 452-1 Shirane-cho, Asahi-ku, Yokohama-shi, Kanagawa Prefecture (56) References: 55-110520 (JP, U)

Claims (2)

[Claims] 1. A hollow box submerged submerged below the surface of water on the coast, the top plate of the box is inclined downward toward the offshore side and opens only at the rear part of the shore side. A portion is provided, the entire top plate is disposed below the water surface, an offshore side plate of the box body is provided with an opening, and a shore side plate of the box body shields a shore side surface. A submerged embankment characterized in that the bottom plate of the box body is connected to each lower side of the side plate. 2. A hollow box submerged submerged below the surface of the water on the coast, wherein the top plate of the box is inclined downward toward the offshore side and is opened only at the rear part on the shore side. Is provided, a projection is arranged on the upper surface excluding the opening, the whole top plate is arranged below the water surface, the side plate on the offshore side of the box is provided with an opening, and the bank of the box is provided. The side plate on the side shields the side surface on the shore side, and the bottom plate of the box body is connected to each lower side of the side plate.