JPS58131211A - Off-shore dam - Google Patents

Abstract

PURPOSE:To maintain the early period wave-breaking effect of an off-shore dam by a method in which specific single blocks are arranged into a dam, and plural dams are set in parallel at an interval of retarding basin. CONSTITUTION:In a single block 1 consisting of a basal board 2 and an uprising wall 3, the length L of the beam 10 of the basal board 2 formed by connecting two beams 10 of a length corresponding to the lower width of a dam by using connecting parts 11 is made longer than the height H of the block 1, the wall is erected with a width corresponding to the width W of the basal board 2, wave-breaking water-permeable holes 12 are formed in the wall 3, and uneven faces are formed at the edge 13 in such a way as to form a water- permeable hole 12a between the block and the adjacent block. The blocks 1 are arranged adjacently toward the widthwise direction in two rows, for example, from the offing to the shore in such a way as to form a retarding basin 14 between the rows. Thus, the early period water-breaking effect of the dam can be maintained for long time without causing any change in the water- permeable holes 12.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an offshore breakwater using wave-dissipating blocks.

Conventionally, odd-shaped blocks have been installed in front of seawalls to prevent waves from overtopping, but from the standpoint of effective use of the area near the shoreline, it is inappropriate to install coastal protection facilities near the shoreline. . Therefore, an effective way to solve this problem is to install offshore breakwaters, which can be expected to prevent erosion and overtopping waves. Conventional offshore breakwaters are masonry breakwaters or irregular block stackers. These banks are usually trapezoidal in cross section and therefore require a large amount of stones or blocks, making construction expensive and uneconomical. Furthermore, even if wave-dissipating blocks with high porosity are stacked in layers, it is extremely difficult to actually arrange them in an ideal manner on site, and furthermore, it is difficult to achieve a certain degree of ideal arrangement immediately after construction. However, as time passes, wave forces cause positional shifts between the blocks, often making it impossible to achieve the initial good wave-dissipating effect.

The object of the present invention is to provide an offshore breakwater that is economical and can maintain a good wave-dissipating effect for a long period of time.

The main feature of this invention is that a bank is formed by arranging single-arm blocks having a size corresponding to a predetermined length of the bank and wave-dissipating permeable holes, and that a plurality of such banks are provided with a retarding section separated. There is a particular thing.

By using a single-arm block that corresponds to the predetermined length of the embankment, there is no vertically laminated structure, which eliminates the problem of positional shift in the conventional wave-breaking block laminated structure, making construction easier and lasting longer. In addition to being able to maintain the good initial effects, it has become possible to adopt an economically extremely effective inverted T-shaped construction cross-section, which was previously forced to have a trapezoidal construction cross-section. It will become.

In addition, wave-dissipating structures with a water retarding section are adopted because waves can be dissipated more effectively if the retarding section is determined according to the wavelength of the main waves in the construction area; You don't have to fight against the wave force completely, you can divide it into multiple parts, so it's a single-arm 7. Tsuku's ability to counter wave force doesn't have to be so thick, which is advantageous for block production.

Embodiments of the present invention will be described below with reference to the drawings.

Figures 1 and 2 show an example of a single-arm block used in the detached breakwater of the embodiment. Block 1 is an integral unit consisting of a base part 2 and an upright wall part 3, and is made of reinforced concrete. . The base portion 2 is made up of two beam-like portions 10.10 having a length corresponding to the lower width of the embankment and connected by a connecting portion 11°11.
In order to obtain sufficient stability, the length L of the beam-shaped portion 10 is formed longer than the height H of the block corresponding to the height of the embankment. Legs 10a projecting slightly downward are provided on the lower surface of both ends of the beam-shaped portion 1o to prevent movement. Standing wall part 3
The Fi base 5 stands upright at a position slightly offset from the center in the longitudinal direction of the base 2 with a width W corresponding to the width of the base 2, and the wall surface is perpendicular to the longitudinal direction of the base 2. A water permeable hole 12 is formed in the wall surface in consideration of wave dissipation properties, and an edge 13 is formed with an uneven surface so that an appropriate water permeable hole 12a is formed between the adjacent block la. ing. Note that the weight of one block is approximately 50 to 100 tons.

A large number of blocks 1 thus formed are arranged adjacent to each other in the width direction to form a breakwater. For example, as shown in FIG. 3, the bones are arranged in two rows.

Due to the presence of the standing wall portion 3, a water retarding portion 14 is formed between the rows as shown in Fig. 4 (al), but since the water retarding portion X is appropriately determined depending on the construction site, the water retarding portion 14 is As shown in (C), X construction, construction 2 as X2% X3
o. Figure (c) shows a 15ft block formed separately.
Although this is used, it is not necessary and may be omitted. In addition, the water retarding section has a wavelength of 1 of the main waves in the construction water area.
It has been experimentally shown that a value of about /4 has a large wave-dissipating effect.

The offshore breakwater constructed in this way reduces the wave height of waves coming from the oil side by half by the first breakwater, and further reduces the wave height by the second breakwater, and the wave height is significantly reduced near the shore. As mentioned above, this detached levee receives a section corresponding to a relatively short predetermined length of one levee (corresponding to the width W of the block). Since the configuration is such that large single-arm blocks l are arranged, there is no change in the water permeation holes 12, and the initial ideal state remains for a long period of time.

In addition, since the block 1 is one piece from the bottom of the embankment to the top, there is no risk of it collapsing like with stacked blocks.
The cross section of the embankment can be formed into an inverted T-shape within a range that is satisfactory in terms of strength. This means that the porosity of the embankment in the conventional stone masonry structure is approximately 0%, and in the conventional block laminated structure it is approximately 50%, whereas in the example above, the porosity is approximately 10%.
This is extremely advantageous in terms of saving materials. Regarding the above-mentioned strength, instead of completely dissipating waves with one levee, the configuration is such that two or more levees are provided with a retarding section to effectively attenuate waves in Stage 5. problem,
Furthermore, the problem of movement caused by wave power is greatly alleviated. Also, in the case of offshore breakwaters with and.

The structure has good water exchange between both sides of the earthen embankment, which is extremely effective in increasing the number of fish and shellfish and securing water areas for aquaculture. In the above example, blocks of the same height were used. However, a different one may be used depending on the need. In some cases, as shown in Fig. 5, the first embankment 20 on the oil side is a submerged embankment, and the second and third embankments 21 are submerged embankments. However, it is better to have a more appropriate shape in consideration of the wave-dissipating effect.

As described above, according to the present invention, it is possible to provide an offshore breakwater that is excellent in the sustainability of the initial good wave-dissipating effect and economical efficiency, and is effective in effectively utilizing the shoreline zone.

[Brief explanation of the drawing]

Figure 1 shows one of the single arm blocks used in the embodiment of this invention.
FIG. 2 is a side view of the same block, FIG. 3 is a schematic front partial perspective view of the first embodiment, FIG. 4(a) is a schematic side view of the first embodiment, and FIG. 4(b) and (c) are schematic side views of modified embodiments of the first embodiment, and FIG. 5(b) and (c) are schematic side views of modified embodiments of the second embodiment, respectively. . DESCRIPTION OF SYMBOLS 1... Single arm block, 2... Base part, 3... Standing wall part, 12.12a... Water permeation hole. Back I Figure 2 Figure 4 Figure S

Claims (1)

[Claims] (1) A levee installed at a distance offshore from the shore has a wave-dissipating permeable hole that has a size equivalent to the predetermined length of the levee and communicates the oil side of the levee with the shore side. A detached shore levee is characterized in that it is formed by arranging single-arm blocks, and that a plurality of the levees are provided substantially parallel to each other with a retarding portion separated from each other.