JP2004143789A - Gravity type offshore breakwater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel gravity type offshore breakwater having a high wave absorbing performance and whose construction is simple. <P>SOLUTION: A swash plate 1 is fitted to the upper face of a box body 8 and fixed thereto. A number of deformed blocks 14 are put in the box body 8 to impart a gravity. A horizontal slit 15 is made to penetrate in the inside and the outside direction a front plate 9 and a rear plate 10. After the breakwater is conveyed to the offshore, and lifted down, then, it is lowered by its own weight and settled down on the sea bottom 4. The surface wave 18a is absorbed by the swash plate 1 and progressive waves 19 in the submarine zone are absorbed by passage into the slit 15 of the front plate 9 and further, absorbed by the deformation blocks 14. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a breakwater used on an offshore seabed with its upper end positioned near the sea surface, and more particularly to a heavy-weight breakwater which is settled by its own weight and installed.
[0002]
[Prior art]
In the sea area facing the open sea, for example, a breakwater is installed at about 100m to 200m offshore to break waves and reduce its wave energy to make the land side a quiet area. Various new types of offshore breakwaters have been developed and some have been installed in actual seas.
[0003]
Many of them are legged offshore breakwaters (swashplate embankments), which are highly reliable due to their simple and robust structure.
[0004]
The above-mentioned detached breakwater is to fix the swash plate installed near the sea surface to the seabed ground with a pile, and to extinguish it by the dissipation of wave energy due to breaking waves on the swash plate. As shown schematically in FIG. 3, a swash plate 1 made of a reinforced concrete plate having a required length in the left-right direction and a required width in the front-rear direction and inclined at a required angle in the front-rear direction so that the front end side is low. The upper end of a tubular jacket 2 having a lower end reaching the sea floor is integrally attached and fixed to a plurality of places on the lower surface of the swash plate 1 with the inclined front end facing the offshore 6. 6 is arranged so as to be orthogonal to the direction of the wave 5a rushing from 6, and is positioned near the sea surface, and the jacket 2 is fitted to the steel pipe pile 3 driven into the offshore seabed 4, or Made of steel pipe inserted through each jacket 2 The swash plate 1 is fixedly supported by the pile 3 by driving the swash plate 3 into the seabed 4, and the wave 5a reaching the swash plate 1 is broken to disperse the wave energy. In addition to the wave elimination, there is a type in which the land 5 is made to be in a calm area by reducing the transmittance of the wave 5a by the reflected wave 5b from the swash plate 1 and thereby eliminating the wave (for example, Patent Document 1).
[0005]
[Patent Document 1]
JP-A-2002-138437
[Problems to be solved by the invention]
However, in the case of a legged type breakwater as described in Patent Document 1, it has a high wave breaking performance as described above, and furthermore, the length of the steel pipe pile 3 and the jacket 2 is changed. It can be used from shallow to large water depths, and has a number of advantages, such as stable structural strength of the fixed part and easy maintenance. Pile driving is indispensable, and is likely to be affected by the weather, which may make construction somewhat difficult.
[0007]
In addition, a typical type of offshore breakwater other than the above-mentioned legged type offshore breakwater is a tetrapod type.
[0008]
In this method, a large number of tetrapots are stacked side by side to form a breakwater, and since the waves are extinguished by the tetrapots, the wave breaking performance is excellent and the construction is simple. Although it has a track record, it is effective at relatively shallow water depths, cannot respond to medium to large water depths, requires frequent maintenance, and is susceptible to waves such as typhoons, and may cause movement or collapse of stacked blocks. There's a problem.
[0009]
In view of the above, the present invention aims to provide a new type of heavy-weight type breakwater which can be easily constructed while utilizing the advantages of the above-mentioned legged breakwater, and has high wave-damping performance.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention has a structure in which a slit is formed in a front side plate and a rear side plate, and a plurality of heavy objects are put in a box having only an upper surface opened so that a gap can be formed therebetween, and the box On the upper surface of the swash plate, the swash plate is attached to the swash plate so as to be inclined so that the front end side is lowered, and the swash plate has a required length in the left-right direction and a required width in the front-rear direction, The length of the box in the left-right direction corresponds to the length of the swash plate in the left-right direction, and the thickness of the box in the front-rear direction is increased.
[0011]
The swash plate, the slits provided in the box, and the heavy objects in the box provide a wave-damping effect and enhance wave-damping performance. Since it is only manufactured at the factory and installed on the seabed, the manufacturing is performed without being affected by the weather, and the construction period from manufacturing to construction can be shortened.
[0012]
In addition, by attaching a pile to the bottom of the box, it can be more stable after installation.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0014]
FIG. 1 shows an embodiment of the present invention. A swash plate 1 made of reinforced concrete or steel or steel reinforced concrete having a required length in the left-right direction and a required width in the front-rear direction, and the swash plate 1 And a box 8 made of reinforced concrete or steel or steel-framed reinforced concrete, which is made to be integrated by attaching to the upper end face, and storing the deformed block 14 as a heavy object in the box 8 Then, the swash plate 1 is fixed to the upper end surface of the box 8 so that a new type of offshore levee I having the swash plate 1 is obtained.
[0015]
The height of the box 8 is set to be slightly lower than the sea surface in accordance with the length in the left-right direction of the swash plate 1 and the height thereof in accordance with the water depth of the offshore sea area where the swash plate 1 is to be installed. A front plate 9; a rear plate 10 having the same length as the front plate 9 in the left-right direction and having a dimension higher than the front plate 9; It has an open-top configuration consisting of left and right side plates 11 and 12, which are adjusted to the height of the side plate 9 and the rear side plate 10, and a bottom plate 13. The front side plate 9 and the rear side plate 10 are respectively provided in the inward and outward directions (thickness). The horizontal slits 15 of a required size penetrating in the same direction are formed, for example, so as to be evenly arranged so that the aperture ratio is about 10%. Odd shape when waves pass through the internal cavity of body 8 Impinge upon the lock 14 to be wave-breaking.
[0016]
After the weight type breakwater I of the present invention is manufactured on land, it is transported by sea to an offshore installation location, and is suspended at the installation location to the seabed.
[0017]
For that purpose, first, after the swash plate 1 and the box 8 are manufactured at a factory on land, a deformed block 14 made of concrete or the like is formed in the box 8 so that a required gap is formed between the blocks 14. By storing and confining, the modified block 14 has a function of imparting weight and having a wave breaking function, and thereafter, a swash plate is provided on the upper end surface of each side plate 9, 10, 11, 12 of the box 8. 1, the lower surface of the swash plate 1 is integrally connected and fixed over the entire circumference, and the new type swash plate-type heavy-weight type breakwater I in which the modified block 14 is confined in a cavity formed by the box 8 and the swash plate 1 is provided. A large number of such heavy type breakwaters I are prepared.
[0018]
Next, the heavy-weight breakwater I of the present invention manufactured at the above-mentioned land-based factory is transported by sea using a carrier to an offshore installation location, and is lowered from the carrier using a cargo handling device at the offshore installation location, Submerge in seawater. At this time, if the ground on the seabed 4 at the installation location is not flat and has irregularities, it is to be equalized in advance by dredging work. Also, in order to suspend the heavy-weight type breakwater I of the present invention, if a suspending piece 16 for suspending is installed in advance as shown by a two-dot chain line in FIG. 1, it can be suspended using the suspending piece 16. .
[0019]
When the heavy-weight breakwater I of the present invention is installed at an offshore installation site, as shown in FIG. 1, the swash plate 1 descends underwater under its own weight in a posture such that the front end (lower end) faces the offshore 6. The bottom plate 13 of the box 8 is seated on the ground of the seabed 4. When the swash plate 1 is installed in this manner, the rear end side (upper end side) of the swash plate 1 is positioned above the sea surface 17 so that the swash plates 1 are sequentially arranged in a direction orthogonal to waves coming from offshore. I do.
[0020]
The water depth of the place where the weight type breakwater I of the present invention is installed can be from a shallow water depth to an intermediate water depth (for example, about 7 m to 10 m), and the thickness of the box 8 in the front-rear direction is 10 m or more. If there is, there is no possibility of falling over even in the case of large waves, and a stable posture is maintained.
[0021]
When installed offshore as described above, the surface waves 18a above the swash plate 1 out of the waves rushing from the offshore 6 are broken by the swash plate 1 and dissipated by dissipating the wave energy, and are also eliminated. By reducing the transparency of the surface wave 18a by the reflected wave 18b from the swash plate 1, the wave can be eliminated. In addition, the underwater traveling wave 19 coming to the front part of the box 8 enters the box 8 through the horizontal slit 15 formed in the front side plate 9, and then collides with a large number of deformed blocks 14 while receiving the waves. While passing through the horizontal slit 15 of the rear plate 10 through the gap between the deformed blocks 14, the underwater traveling wave 19 is canceled by the deformed block 14 and passes through the horizontal slit 15 formed in the front plate 9. Will also be extinguished.
[0022]
However, in the case where the weight type breakwater I of the present invention does not have the swash plate 1 and the upper surface of the box 8 is a weight type breakwater, the surface wave 18a is Not only can the waves be cut off by overtopping the quay, but when strong waves rush, waves are sprayed, which hits the upper surface of the quay and causes rust. The weight type breakwater I according to the present invention having 1 does not have such a problem.
[0023]
Next, FIG. 2 shows another embodiment of the present invention. In the same configuration as the embodiment shown in FIG. 1, the lower end is pointed at a plurality of lower surfaces of the bottom plate 13 of the box 8. The short pile 20 is attached downward, and the other configuration is the same as that shown in FIG. 1, and the same components are denoted by the same reference numerals.
[0024]
According to this embodiment, when the gravity type breakwater I of the present invention is lowered and installed at an offshore installation site, when the ground of the seabed 4 is a clay layer, the bottom plate 13 is seated on the seabed 4. The pile 20 is inserted into the ground by the movement of the weight type breakwater I of the present invention which descends by its own weight, and the pile 20 functions as a detent. Thereby, it can be more firmly prevented from shifting from the seabed 4 at the installation location.
[0025]
The present invention is not limited to the above embodiment. For example, the deformed block 14 may have a shape other than that shown in the drawings, and a solid such as stone may be used instead of the deformed block 14. Any other configuration may be used as long as it is heavy and a gap is formed at the time of storage, and various changes may be made without departing from the gist of the present invention. Of course.
[0026]
【The invention's effect】
As described above, according to the weight type breakwater of the present invention, a large number of heavy objects are put in a box having only the upper surface opened by forming a slit in the front side plate and the rear side plate so as to have a gap therebetween. And a swash plate is attached to the upper surface of the box by inclining so that the front end side is lowered, and the swash plate is required to have a required length in the left-right direction and a required width in the front-rear direction. The length of the box in the left-right direction corresponds to the length of the swash plate in the left-right direction, and the thickness of the box in the front-rear direction is increased, and the lower surface of the bottom plate of the box Since the pile having a required length is attached downward at a plurality of locations, the following excellent effects can be obtained.
(1) Since it has a swash plate and is of a weight type, surface waves can be eliminated by the swash plate, and underwater traveling waves pass through a slit formed in the front plate of the box. In addition to being able to eliminate waves caused by heavy waves in the case, it can be installed stably simply by submerging it on the sea floor, construction can be performed easily, and the frequency of maintenance is further reduced be able to.
(2) Since production can be performed on land, it can be produced without being affected by the weather, the production process can be shortened, and after transported to the installation location by sea transportation, it is suspended by a crane etc. It can be installed simply and in a short time only, the construction date can be shortened, and the cost can be reduced.
(3) Since heavy items are stored and installed in the case, it is possible to confine heavy objects and prevent movement and collapse.
(4) By attaching a pile to the lower surface of the bottom plate of the box, the pile can be inserted into the ground when it comes into contact with the seabed by its own weight when the ground on the seabed is a clay layer, and the movement is more firmly prevented. Can be.
[Brief description of the drawings]
FIG. 1 is a cut-away side view showing an embodiment of a weight type breakwater according to the present invention.
FIG. 2 is a cut-away side view showing another embodiment of the weight type breakwater according to the present invention.
FIG. 3 is a schematic side view showing an example of a conventional legged type breakwater.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Swash plate 4 Sea bottom 8 Case 9 Front side plate 10 Rear side plate 13 Bottom plate 14 Deformed block (heavy object)
15 Horizontal slit (slit)
18a Surface wave 19 Underwater traveling wave 20 Pile

Claims (3)

A large number of heavy objects are placed in the open box with only the upper surface manufactured by forming slits in the front plate and the rear plate so that there is a gap between them, and the upper surface of the box is inclined so that the front end side is lower. A heavy-weight type breakwater characterized by having a configuration in which a swash plate is attached to the quay and integrated. The swash plate has a required length in the left-right direction and a required width in the front-rear direction. The length in the left-right direction of the box corresponds to the length in the left-right direction of the swash plate. The weight type breakwater according to claim 1, wherein the thickness in the direction is increased. The heavy-weight breakwater according to claim 1 or 2, wherein the pile is attached downward at a plurality of locations on the bottom surface of the box.

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