JPH11350450A - Slope slit caisson - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a function by forming hollow chambers having transmission walls with opening sections at the front section of a caisson main body with its front face inclined above and below the still water surface. SOLUTION: The front face 12a of a caisson main body 12 is inclined above and below the still water surface, first and second transmission walls 14, 16 are provided at the prescribed distances from the front face 12 a, first and second hollow chambers 18, 20 are formed, and vertical slits 14a, 16a are provided on the walls 14, 16 to form a slope slit caisson. The numerical apertures of the walls 14, 16 and the interval between the walls 14, 16 are changed to adjust the wave suppressing effect and reflecting effect. Streams passing through the vertical slits 14a, 16a are generated to reduce pressure, thus the pressure applied to the caisson is reduced. The pressure receiving area is decreased by the vertical slits 14a, 16a, the peak phase of wave force is drifted according to the positions of constituting members, the wave pressure resultant force is reduced, thus sliding stability can be improved. Since the transmission walls 14, 16 are inclined, wave-resistant stability can be secured by the normal lightweight caisson.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to slope slit caissons. More specifically, the present invention
The present invention relates to a slope slit caisson excellent in reflectivity and economy. INDUSTRIAL APPLICABILITY The slope slit caisson of the present invention is applied to a sea area with a water depth and a wave height outside the applicable range of a direct breakwater.

[0002]

As a breakwater which is widely used at present, a so-called breakwater block-covered breakwater is known. The breakwater-blocking embankment is a breakwater with a wave-breaking block installed on the front of the caisson to reduce the wave power and reduce the wave power.However, it is only necessary to install a ready-made wavebreaker block during construction. It has the advantage of being simple. However, since the wave-dissipating block itself is expensive, there is a disadvantage that the construction cost is high, and this is particularly remarkable when a wave-dissipating block-covered embankment is to be constructed in a deep sea area. Further, in the case of constructing a wave-dissipating block covering levee in a sea area of high waves, a heavy-weight wave-dissipating block is required, which further increases the cost. Further, when the wave-breaking block covering levee is to be constructed for a plurality of years, the wave-breaking block must be removed and installed before and after the construction, which has a disadvantage that the construction becomes extremely complicated.

On the other hand, a so-called upright slit embankment is known as a breakwater which is relatively frequently used. The upright slit bank, as shown in FIG.
It is provided on the front of the caisson body, and has a hollow chamber (this chamber is generally called “water-repelling chamber”) constituted by a permeable wall, a bottom floor plate, and an upper floor plate, and is generated from the permeable wall. The energy is consumed by the swirling vortex. However, the upright slit embankment has a problem that the wavelength that can be eliminated is limited to a short wavelength, and the wavelength band is limited to a certain band, so that it has difficulty in versatility.

[0004] Under such circumstances, efforts have been made to develop new types of breakwaters, and various types of breakwaters have been proposed, but all have problems in terms of workability and cost. At present, there are very few practical or versatile breakwaters. Therefore,
An object of the present invention is to provide a versatile breakwater that is excellent in wave extinction / reflection and economy.

[0005]

According to a first aspect of the present invention, there is provided a sloped slit caisson having a caisson main body having a front surface inclined above and below a still water surface, and a first hollow caisson main body. A first chamber provided at a first distance from the front of the caisson body to form a chamber.
And the first transmission wall is formed with one or more openings.

The slope slit caisson according to claim 2 of the present application is the slope slit caisson according to claim 1,
In order to form one or more other hollow chambers on the front side of the caisson main body, the caisson main body further includes one or more transmission walls provided at a predetermined distance from the front surface of the caisson main body. The above-mentioned openings are formed respectively.

A slope slit caisson according to claim 3 of the present application is characterized in that, in the slope slit caisson according to claim 1 or 2, the opening is an elongated opening extending in a vertical direction, that is, a vertical slit. Things.

According to a fourth aspect of the present invention, there is provided a slope slit caisson according to the first or second aspect, wherein the opening is an elongated opening extending horizontally, that is, a horizontal slit. Things.

A slope slit caisson according to claim 5 of the present application is the slope slit caisson according to claim 1 or 2, wherein the opening is a circular or polygonal opening.

[0010]

Next, an embodiment of the present invention will be described in detail with reference to the drawings. A slope slit caisson according to a first embodiment of the present invention, which is generally indicated by reference numeral 10 in FIG. The caisson body 12 has a front surface 12a,
As shown in FIG. 2, it is inclined at locations above and below the hydrostatic surface.

The inclined slit caisson 10 further includes a first transmitting wall 14 and a second transmitting wall 16 at predetermined distances d1 and d2 from the front surface 12a of the caisson main body 12, respectively. As a result, a first hollow chamber, that is, a water-reducing chamber 18, and a second hollow chamber, that is, a water-free chamber 20, are formed on the front side of the caisson body 12. In addition, in this specification, a "front surface" and a "front side" mean the surface and the side which a wave hits, respectively.

A first transmitting wall 14 and a second transmitting wall 16
Are provided with elongated openings, that is, vertical slits 14a and 16a, which extend in the vertical direction. In the embodiment shown in FIG. 1, four vertical slits 16a are provided.
Is shown, but the number of the vertical slits 16a is not limited to four, and may be any number of one or more (in FIG. 1, the vertical slits 14a are not shown, but the vertical slits 14a are also vertical slits). 16a).

By changing the aperture ratio of the transmitting walls 14, 16 and the distances d1, d2 between the transmitting walls 14, 16, the wave-elimination effect and the reflection effect can be adjusted. Generally, the aperture ratio is preferably about 10 to 30%. The interval between the transmission walls (that is, the width of the hollow chamber) is 10 to 10 of the wavelength.
When it is about 20%, the reflectance becomes small.

In FIGS. 1 and 2, a portion 12b of the caisson body 12 is a portion for preventing overtopping,
It is not essential to the slope slit caisson 10 of the present invention. The portion 12c of the caisson body is a portion for adjusting the water depth, and its height is increased or decreased according to the water depth of the place where the breakwater is installed.

The inclined slit caisson 10 of the present invention has a characteristic of high sliding stability for the following reason. First, due to the presence of the permeable wall, a flow through the vertical slit is generated and the pressure is reduced, so that the pressure acting on the caisson is reduced, and the presence of the vertical slit reduces the pressure receiving surface, Thereby, sliding stability is improved. Secondly, for example, when the wave pressure peaks at the rear wall of the retarding chamber, the wave pressure does not peak at the transmission wall, and conversely, when the wave pressure peaks at the transmission wall. On the rear wall of the water chamber, the wave pressure does not peak, and the phase of the wave force shifts depending on the position of each component member, so that the wave pressure resultant force is reduced, thereby enhancing the sliding stability. Thirdly, for example, when the wave pressure peaks at the rear wall of the retarding chamber, the water level in the retarding chamber becomes higher than the still water level, and the weight of the wave acts on the bottom plate of the retarding chamber, thereby stabilizing the sliding. Sex is enhanced. Fourth, since the wave acts on the inclined surface, the horizontal component force of the wave is reduced, and the vertical component force is increased, thereby increasing the sliding stability.

The inclined slit caisson 10 of the present invention is also provided.
Has a characteristic that the wave resistance stability is high. That is, in the slope slit caisson 10 of the present invention, the front surface 12a of the caisson main body 12 and the transmission walls 14, 16 are inclined at locations above and below the still water surface, so that about 70% to 90% of a normal caisson. It is expected that the required wave resistance stability will be obtained even with the weight.

The present invention is not limited to the above embodiments of the invention, and various modifications can be made within the scope of the invention described in the claims. It goes without saying that it is included in.

For example, in the above embodiment, 2
Although three permeable walls 14 and 16 are provided and the hollow chamber is formed in a double manner, as shown in FIG. 3, only one permeable wall may be provided and the hollow chamber may be formed as a single cavity (see FIG. 3). , The permeable wall is shown at 30 and the cavity is shown at 32).
Alternatively, although not shown, three or more permeable walls may be provided, and the number of hollow chambers may be three or more. In general, when the number of transmission walls is increased, a frequency band having good wave-elimination performance is widened.

Further, in the above embodiment, the opening formed in the transmission wall is an elongated opening extending in the vertical direction, that is, a vertical slit. However, as shown in FIG. An elongated opening or horizontal slit 34 extending in the horizontal direction may be provided. Alternatively, although not shown, a circular or polygonal opening may be provided in the transmission wall.

Further, in the above embodiment, a portion 12b for preventing overtopping is provided on the upper part of the caisson main body 12.
Although it is shown as a so-called impervious caisson, depending on the purpose, as a so-called transmissive caisson that does not block the back of the caisson, or as a so-called translucent caisson that partially blocks the back of the caisson Is also good. The transmission type caisson is suitable for keeping seawater in the harbor clean because the seawater in the harbor surrounded by the breakwater is exchanged. A translucent caisson is also suitable for balancing calm and seawater exchange in a port.

[0021]

The slope slit caisson of the present invention is more economical than the currently widely used wave-breaking block-covered embankment and, depending on the conditions, even more economical than an upright slit embankment. Moreover, the slope slit caisson of the present invention is superior in sliding stability and wave resistance stability as compared with the upright slit bank. Also, the slope slit caisson of the present invention,
Any of a transmission type, a semi-transmission type, and a non-transmission type can be selected according to the purpose. Further, unlike the breakwater block covering embankment, it is not necessary to remove and install the wavebreak block before and after the construction, which contributes to simplification of the construction and shortening of the construction period.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a slope slit caisson according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG.

FIG. 3 is a view similar to FIG. 2 of a slope slit caisson according to another embodiment of the present invention.

FIG. 4 is a perspective view showing a slope slit caisson according to still another embodiment of the present invention.

FIG. 5 is a schematic sectional view schematically showing a conventional upright slit bank.

[Description of Signs] 10 Slope slit caisson 12 Caisson main body 14 First permeable wall 16 Second permeable wall 14a, 14b Vertical slit 18, 20 Hollow chamber

Claims (5)

[Claims] 1. A caisson main body having a front surface inclined at a position above and below a still water surface, and a first hollow chamber formed at a front side of the caisson main body.
A first transmission wall provided at a first distance from the front surface of the caisson main body, wherein the first transmission wall has one or more openings formed therein. caisson. 2. The apparatus according to claim 1, further comprising one or a plurality of transmission walls provided at a predetermined distance from a front surface of the caisson main body to form one or more other hollow chambers in front of the caisson main body. The slope slit caisson according to claim 1, wherein one or more openings are respectively formed in the wall. 3. The slope slit caisson according to claim 1, wherein the opening is an elongated opening extending vertically, that is, a vertical slit. 4. The slope slit caisson according to claim 1, wherein the opening is an elongated opening extending horizontally, that is, a horizontal slit. 5. The slope slit caisson according to claim 1, wherein the opening is a circular or polygonal opening.