JPS6314126B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a box-shaped block for seawalls and a stepped seawall using the same, and more specifically, to a box-shaped block for seawalls and a step-type seawall using the same. By constructing the slope of the coastal embankment and bringing the flow of reflected waves closer to a steady flow, we can prevent scouring and sucking out of the front of the embankment.
This invention relates to a box-shaped block for constructing a permanent seawall and a stepped seawall using the same.

Accidents frequently occur in which seawalls, which have traditionally been built on sandy beaches to prevent coastal erosion, are damaged. This is due to the scouring of the front surface of the embankment foundation due to strong reflected waves, and the strong reflected waves that cause the interstitial water within the embankment to collide with the concrete of the embankment, and are sucked out to the front of the embankment through a small gap in the embankment, accompanied by earth and sand. It is empirically known that this is due to a phenomenon.

Therefore, a method of covering the front wall with glue was adopted, which can withstand some amount of suction and can stand on its own and continue to function even if some soil flows out from the back. The butt wall type has a wide bottom plate and a fairly large slope of about 1:0.5 in order to withstand scouring in front of the levee body. However, in this buttress-type seawall, the energy of the reflected waves is not attenuated very much, causing the beach to recede significantly, and damage and collapse accidents continue to occur due to scouring and suction of the front surface by the reflected waves.

Although all of these seawalls are made of strong concrete, the inventors believe that they do not have strong walls to protect against the waves that hit the coast with a large amount of energy, and instead attenuate the wave energy. In particular, we focused on the fact that a seawall that weakens the energy of reflected waves and allows free flow of pore water at the back of the dam body is stronger as a result. Japanese Patent Application No. 109329/1987 discloses an embankment covered with concrete blocks having a large number of water reservoirs that allow water to be released slowly until the waves arrive.

The present invention further increases the water storage capacity of the concrete blocks and increases their wave-dissipating effect, and by building the entire slope in a step-like manner and placing the concrete blocks horizontally, it saves the effort of forming slopes. It is easy to work, prevents blocks from collapsing, and makes the seawall itself more stable. That is, the present invention aims to provide a permanent seawall by breaking waves and turning the reflected waves into a gentle steady flow to prevent scouring of the front surface. From the rear edge to the rear wall,
A concrete box with a side wall integrally planted from at least one side edge and a front wall from the front edge, characterized in that a part of the front wall is missing from the bottom plate surface. Furthermore, the blocks are arranged with the front walls facing the ocean side, and the water storage surface is formed in a step-like manner.

The block according to the invention consists of a strong base plate and a rear wall, side walls and front wall cast integrally with the base plate. Since the box-shaped blocks are closely arranged in a row, even if one side wall is missing, the side wall of the adjacent block will essentially serve as the side wall, so it is only necessary to provide it on one side. There is no problem in providing it for both. A portion of the front wall is required to be missing from the bottom plate surface, and the missing portion is preferably the side without the side wall, and the remaining front wall is integral with one side wall and the bottom plate. The front wall is a part that faces waves from the ocean, so it is desirable that it be sturdy and slope slightly toward the rear wall so that it can easily withstand wave energy. The side walls are installed perpendicularly to the bottom plate, and when they are arranged in a row on the same plane, the side walls of adjacent blocks are in close contact with each other, resulting in a water storage tank with a part of the front wall missing. The shape and width of the missing part will vary depending on various conditions such as the coastal situation, the construction site of the sea wall, the height and construction method, and the depth of the water storage tank, but it will serve as a container for storing seawater when waves hit. , it is desirable that when the waves recede, the flow will gradually flow out, and the overall reflected flow will be close to a steady flow. Therefore, combined with the wave breaking effect caused by climbing up the front wall, the energy of the reflected waves is significantly attenuated, resulting in a gentle flow, and before the next wave hits, the water tank is almost empty and ready to store the next wave. be able to.

Hereinafter, the present invention will be described in detail by way of examples with reference to the drawings.

FIG. 1 is a perspective view of a concrete block according to the present invention. Reference numeral 1 denotes a bottom plate, which is a reinforced concrete box body in which a rear wall 2, a side wall 3, and a front wall 4 are integrally cast from each edge. One edge 5
Although no side wall is installed from the top, since box-shaped blocks of the same shape are closely juxtaposed, the side wall provided at the other end serves as the side wall of the adjacent block. A cutout 6 is provided on the edge 5 side of the front wall 4. When looking at one block, a water storage tank 7 is formed by the rear wall, its own side wall, the side wall of the adjacent block, and the front wall, but since this water storage tank 7 has a missing part 6, it cannot be seen from the front. Even if the surging seawater is stored, it will flow out from the missing part 6 when the waves recede. However, because it is blocked by the front wall 4 and flows out slowly,
The initial flow velocity of the reflected waves is significantly reduced, and the flow of the reflected waves becomes uniform as a whole.

In the one shown in FIG. 2, the front wall 4 is curved inward to reduce the impact received from waves. In addition, the front wall may not have a curved surface, but may have an inwardly inclined surface.

Further, it is also possible to use a structure in which front walls having missing portions are arranged in two parallel rows, and the front walls are lower than the rear wall, and the rear walls are approximately equal to the rear wall.

FIG. 3 shows a sectional view of a seawall formed using the box-shaped block according to the present invention. 9 is the foundation before building the embankment body, and foot protection work 8 was constructed at the tip facing the ocean. Next, the first stage box-shaped block 10
A is installed horizontally in a line, crushed stones, cobblestones, gravel, etc. are piled up behind the seawall wall 2 to the height of the rear wall, and second-stage box-shaped blocks 10b are installed horizontally in a line on top of it. In this way, they were stacked one after the other to a predetermined height, 3rd, 4th, etc. At this time, the rear wall 2 has the function of a retaining plate, and if the rear wall is tilted rearward in some cases, the embankment body can be made more stable.

FIG. 4 is a plan view of a portion of FIG. 3. Reference numeral 8 indicates a foot protection work constructed on the ocean side, which consists of a first stage box-shaped block 10a, a second stage box-shaped block 10b, a third stage box-shaped block 10c, and a fourth stage box-shaped block 10d. Stack up. As shown by the arrow in FIG. 3, waves crashing from the ocean fill the water storage tank of the first stage box-shaped block 10a, and then fill the water storage tank of the second stage box-shaped block 10b, and in this way, the waves successively move forward. As the waves pass over the wall, the seawater is trapped in the reservoir, causing the wave's power to attenuate. When the waves recede, reflected waves flow down from the missing parts of the box-shaped blocks at each level, but their momentum is reduced as they are blocked by the front wall, and there is no force to scour the front of the embankment. In particular, if the position of the missing part is shifted for each stage as shown in Figure 4,
As shown by the arrow, the reflected wave is forced to take a further detour,
Reduce that energy and stabilize the embankment body.

As described above, according to the present invention, not only is it possible to prevent scouring of the front surface of the levee body, but the box-shaped block itself has the function of a retaining plate, the construction work of the levee body is easy, and the bottom plate is horizontal. Therefore, the stability of the embankment body is good.

[Brief explanation of the drawing]

The drawings show embodiments of the invention, FIGS. 1 and 2.
The figure is a perspective view of the box-shaped block, FIG. 3 is a sectional view of the seawall, and FIG. 4 is a plan view of FIG. 3. In the drawing, 1 is the bottom plate, 2 is the rear wall, 3 is the side wall, 4 is the front wall, 6 is the missing part, 7 is the water storage tank, 8 is the foot protection work,
9 is a base, and 10 is a box-shaped block.

Claims (1)

[Claims] 1. A rear wall from the rear edge of a rectangular horizontal bottom plate,
A box-shaped block made of concrete with a side wall integrally planted from at least one side edge and a front wall integrally planted from the front edge, with a part of the front wall missing from the bottom plate surface. . 2. The box-shaped block according to claim 1, wherein the front wall is inclined toward the inside of the block. 3. From the rear edge of the rectangular horizontal bottom plate,
A box-shaped block made of concrete with a side wall integrally planted from at least one side edge and a front wall integrally planted from the front edge, with a part of the front wall missing from the bottom plate surface. The lower part of the slope is leveled, and the box-shaped blocks are arranged in a row with the front wall facing the ocean to form the first water storage tank, and then the next stage of the slope is laid. are leveled to the height of the rear wall, and the box-shaped blocks described above are placed in a row with the front wall facing the ocean side to form a second-tier water storage tank, and in this way, the water storage tanks are sequentially built into stairs. A stepped seawall formed in the shape of a