JPS60261815A - Method of protecting weir body - Google Patents

Abstract

PURPOSE:To damp waves energy and to prevent the occurrence of a suction phenomenon, by a method wherein a face of slope is wholy covered with concrete blocks, and dashing sea water is temporarily stored with the aid of a wave crushing plate formed to the one end of the block. CONSTITUTION:A wave crushing plate 2 is integrally filled in the side end of a bottom plate 1, a wall plate drainage passage forming part 7 is formed by notching the one end of the wave crushing plate 2 to form a concrete block for revetment. When the blocks for revetment are aligned in a manner that the blocks are firmly adhered to each other and stages are arranged in a zigzag, an end part 8 on the off-shore side of other block bottom plate 1 is engaged with a recess 5 formed in the under surface of a bottom surface 3 of the wave crushing plate 2 to form a drainage passage with the drainage passage forming parts 7. Dashing waves violently collide with wave crushing surfaces 6a and 6b for crushing, and a part of sea water is stored in water storage parts 9a and 9b. Further, when waves are rolled out, reflection waves flows down through the drainage passage in the block at each stage, but a power is decreased thanks to the wave crushing plate 2, and has no power enough to allow excavation of the front of a weir by scouring.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a plurality of stages of wave-breaking plates, which can be called small levees, on a slope to attenuate the energy of waves hitting the coast, and at the same time reduce the amount of seawater that hits the shore. This invention relates to a seawall method that prevents scouring and suction phenomena on the front of the embankment body and erosion of the shoreline, and rather increases the land area by temporarily storing reflected waves in a wave-breaking plate and bringing the flow of reflected waves closer to a steady flow.

[Prior art]

There have been many accidents in which seawalls, which have traditionally been built on sandy beaches to prevent coastal erosion, are damaged.

This is due to strong reflected waves scouring the front of the embankment foundation, and strong reflected waves that flow down the concrete surface of the embankment as jets, sucking out pore water within the embankment from small gaps or cracks in the embankment, accompanied by earth and sand. It is empirically known that this is due to the so-called suction 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 bulwark type has wide roots and a slope of 1:0.5 to withstand scouring in front of the embankment body.
It is quite large. However, in this buttress-type seawall, the energy of the reflected waves is not attenuated very much, causing the beach to recede significantly, and the front surface is scoured and sucked out by the reflected waves, resulting in frequent failures and collapses.

[Problem that the invention seeks to solve]

All of these seawalls are made of strong concrete, but the waves that hit the shore with great energy collide with the concrete topcoat, creating strong reflected currents that scour the foundation of the embankment. Therefore, if the slope is thoroughly covered with concrete blocks and multiple stages of wave-breaking plates capable of temporarily storing seawater are installed, the amount of water from the crashing waves will be reduced by the amount of water stored in the wave-breaking plates. The force of moving upstream through the levee body is weakened. Also, when the waves recede,
Because the seawater passes through a narrow drainage channel between wave-breaking plates, it cannot flow down all at once, and is similar to a regular flow with low energy.
The present invention was completed based on the knowledge that the embankment foundation was not scoured.

[Means for Solving Problems] and [Operation] The present invention has the function of completely covering the slope using concrete blocks, attenuating the waves that hit the concrete blocks, and temporarily storing the seawater that hits the concrete blocks. The present invention is characterized by providing a plurality of stages of wave-breaking plates having a wave-breaking plate and providing a drainage channel between the wave-breaking plates so that almost all of the temporarily stored seawater can be discharged before the next wave.

In the present invention, in order to prevent earth and sand from being sucked out from the embankment body by waves, the slope is thoroughly covered with concrete.

Concrete may be placed over the entire slope, but concrete blocks having wave-breaking plates may also be placed densely.

The wave-breaking plate must be installed approximately parallel to the shoreline and must have sufficient strength to collide with the incoming waves and attenuate the energy of the waves. More importantly, it has the ability to temporarily store seawater that has washed over it. For this purpose, it is desirable that the wave breaking plate be provided with a slight inclination toward the slope side. Further, the weir plate may have a certain length so that seawater does not easily flow down, or a weir plate may be extended from the wave breaking plate to prevent free flow.

A drainage channel is provided between the wave breaking plates. The drainage canal is
In addition to being a bottleneck that prevents the free flow of seawater,
The width should be at least 70 mm, preferably 100 mm or more, so that there is no risk of blockage due to attachment of organisms such as shellfish and seaweeds. ,! Note that as the wave breaking plate, a concrete block having a large number of protrusions and a high porosity may be buried in the front surface of the bottom plate. In this case, the wave-breaking plate itself can have a temporary water storage capacity and a drainage channel in addition to its wave-breaking ability.

In this way, the slope is thoroughly covered with concrete,
The wave-breaking plates are arranged in a plurality of stages, and a drainage channel is formed between the wave-breaking plates. The waves that hit the dam reduce their energy and seawater volume because they pass over the breaking plates one after another from below, and do not run up to the upper part of the dam body. When it is pulled, it is blocked by a wave breaking plate and flows down one by one through a narrow drainage channel. Therefore, combined with the wave-breaking effect of the wave-breaking plate, the energy of the reflected waves is significantly attenuated, resulting in a gentle flow similar to a steady flow, which does not scour the embankment foundation. The water will drain away before the next wave hits, allowing you to prepare for the next wave. The present invention is not limited to the coast, but can be implemented on any embankment such as a lakeshore or a riverbank.

〔Effect of the invention〕

The present invention, in which wave-breaking plates are arranged in multiple stages on the slope leaving drainage channels, attenuates the energy of waves hitting the shore, and at the same time temporarily stores the seawater that hits the shore in the wave-breaking plates, reducing the amount of reflected waves. The flow can be brought closer to a steady stream, preventing scouring and suction phenomena on the front of the levee body and erosion of the coastline, and rather increasing the land area.

〔Example〕

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 used in the present invention. 1 is a bottom plate; 2 is a wave breaking plate installed on the bottom plate 1; a part of the bottom 3 extends outward from the bottom plate, and forms a recess 5 with an ocean side end 4 of the bottom plate. 6 is a curved wave breaking surface, which receives waves and attenuates energy. Since the wave breaking plate 2 is a part that receives particularly strong impact from waves,
It was tilted toward the bottom plate 1 side. The wave-breaking plate 2 is shorter than the bottom plate 1, and is located on an extension of the wave-breaking plate on the surface of the bottom plate 1, and the portion where the wave-breaking plate is not provided is defined as a drainage channel forming portion 7. Reference numeral 8 denotes a coast-side end of the bottom plate 1, and 9 a water storage portion formed by the bottom plate 1 and the wave-breaking plate 2.

Figure 3 is a layout diagram of the seawall using concrete blocks in Figure 1, viewed perpendicular to the slope, and Figure 4 is the IV- diagram in Figure 3.
It is a sectional view taken along the line IV. During construction, by arranging the blocks for the seawall in close contact with each other vertically and horizontally, the coast-side end 8 of the bottom plate 1 fits into the recess 5 formed at the lower part of the bottom surface 3 of the wave-breaking plate. The drainage channel forming portion 7 remains as it is as a missing portion of the wave breaking plate, and becomes a drainage channel 12. 10 is the slope, and 11 is the foot protection work. Waves that hit from the ocean first break on the wave surface6.
It collides with the seawater a and mechanically breaks up, and a part of the seawater is stored in the water storage part 9a. The remaining seawater further collides with the wave breaking surface 6b of the upper block and breaks, and a portion is stored in the water storage section 9b. As the seawater rises to the upper level, the amount of seawater decreases significantly and wave energy also attenuates. When the waves recede, the seawater stored in the water storage section 9 is blocked by the wave breaking plate 2 and passes through the drainage channel 12, which is the narrow part, to the lower water storage section 9.
The water enters the water and further flows down the drainage channel 12 at the lower level. In this way, the anti-b wave resistance cannot flow down all at once, so
Decreased.

The flow weakens and becomes close to a steady flow, and no scouring occurs on the front of the frame.
Furthermore, there is no suction on the back side of the embankment body. In this example, when placing the concrete blocks on the slope, the upper and lower tiers were staggered, but it is not necessary to stagger them.
It may be a direct drainage channel.

FIG. 2 is a perspective view of another concrete block embodiment. A wave breaking surface 6 is formed by combining planes, and one end of the wave breaking plate 2 is made to protrude from the bottom plate 1. Therefore, a wide flat surface remains on the bottom plate at the other end of the wave-breaking plate 2, but a portion of this area overlaps with the protruding part of the wave-breaking plate of the adjacent revetment block during construction, so only the remaining part becomes the drainage channel. This corresponds to the forming part 7.

The flow velocity of the reflected flow passing through the drainage channel 12 increases only in this part, and there is a risk that a suction phenomenon may occur at the contact surface between the bottom plates. 12, the suction phenomenon can be completely prevented.

Furthermore, the wave breaking plate 2 may be divided into two parts and the drainage channel forming part 7 may be provided in the middle part, or the wave breaking plate 2 may be provided in the center part of the bottom plate 1. Furthermore, the amount of temporarily stored water can be increased by providing one weir plate on the wave breaking plate to form a square shape.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIGS. 1 and 2 are perspective views of concrete blocks, FIG. 3 is a layout of concrete blocks viewed from the vertical direction of the slope, and FIG.
It is a sectional view taken along the line IV-IV in the figure. In the drawing, 1 is the bottom plate, 2 is the wave breaking plate, 4 is the ocean side end, 5 is the recess, 6
is the breaking wave surface, 7 is the wall plate drainage channel forming part, 8 is the coast side end, 9
1 is a water storage part, 1o is a slope, 11 is a foot protection work, and 12 is a drainage channel. Patent applicant Nippon Sohan Co., Ltd. Agent Patent attorney Sadako Suzuki 109 Life 1 Figure Tail 2 Figure

Claims (1)

[Claims] Concrete blocks are used to completely cover the slope, and the concrete blocks are equipped with multiple stages of wave-breaking plates that have the function of attenuating the crashing waves and temporarily storing the crashing seawater. A seawall method in which a drainage channel is installed between the boards to drain almost all of the temporarily stored seawater before the next wave.