JPH0448123B2 - - Google Patents

Description

[Detailed description of the invention] Industrial applications The present invention relates to a breakwater.

BACKGROUND ART Conventional breakwaters are generally constructed of a simple breakwater body or made of tetrapods (registered trademark). This Tetrapod (registered trademark) consists of a star-shaped concrete block with four protrusions forming an angle of 120 degrees with each other, and the embankment body is constructed by stacking multiple blocks. .

Problems to be Solved by the Invention However, in the conventional breakwater with a simple embankment structure as described above, there is no flow of water between the outside of the bay and the inside of the bay, and the blocks are piled up as described above. It is known from experience that the distribution of water is extremely poor. In addition, when the blocks are piled up as described above, there is a problem that foreign matter accumulates in the gaps between the protrusions of the blocks, and because of poor water circulation, this foreign matter is likely to rot.

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems and provide a seawall that allows water to flow well in and out of a bay.

Means for Solving the Problems In order to solve the above problems, the present invention provides a suction port on the outside of the bay, a small diameter portion formed on the inside of the bay from the suction port, and a small diameter portion formed on the inside of the bay from the small diameter portion. A plurality of pillar-shaped wave absorbing and wave dissipating blocks each having a through hole formed in the length direction with a large diameter portion arranged horizontally and stacked in an upward slope from the outside of the bay to the inside of the bay. It is.

Effect According to such a configuration, waves propagating from the outside of the bay toward the inside of the bay are guided from the suction port of the through hole to the small diameter section, and then propagated from the small diameter section to the large diameter section. Then, the above wave reaches the small diameter part from the suction port, and is guided to the large diameter part while undergoing a wave-dissipating effect by colliding with the inner surface of the small diameter part, and the cross-sectional area of the passage increases as it moves from the small diameter part to the large diameter part. Wave dissipation is also achieved by absorbing energy due to an increase in , and also by absorbing energy due to collision with the inner surface of the large diameter portion.

At this time, as the waves pass through the through hole, a water flow toward the inside of the bay is generated inside the through hole.
Furthermore, when the waves return to the outside of the bay, the water existing inside the through-hole flows out toward the outside of the bay because the through-hole is sloped downward toward the outside of the bay. Therefore, the impurities present inside the through-hole flow out to the inside or outside of the bay along with the water flow, and are prevented from staying inside the through-hole.
Furthermore, since water flows between the inside of the bay and the outside of the bay, water inside the bay is exchanged with water outside the bay.

Embodiment FIG. 1 shows a cross-sectional view of an embodiment of a breakwater according to the present invention. Here 1 is seabed 2
The upper surface 3 of this foundation 1
For example, from the outer side 4 of the bay to the inner side 5 of the bay,
It is formed so that it slopes upward at an angle of . A plurality of wave absorbing wave-dissipating blocks 6 are stacked on the upper surface 3 of the foundation 1, and the wave-absorbing blocks 6 are arranged so as to be inclined corresponding to the upper surface 3 of the foundation 1. An upper mounting part 7 is arranged above the wave dissipating block 6 at the top. This mounting part 7
The upper surface 32 of the wave dissipating block 6 is configured to be horizontal against the inclination of the wave dissipating block 6, and is designed to allow people, vehicles, etc. to pass through.

FIG. 2 shows the detailed structure of the wave absorbing and dissipating block 6. As shown in FIG. Here, 8 is a block, which is made of a concrete material with a rectangular cross section, and has four side surfaces 9, 10, 11, and 12 appearing on its outer surface. A plurality of convex portions 13 each having a constant length and a constant height are formed on one side surface 9 at constant distances in the length direction of the block 8 . Each convex portion 13 is formed over the entire length of the side surface 9 in the width direction (that is, one side of the rectangle). A concave portion 14 corresponding to the convex portion 13 is formed on the side surface 11 located on the opposite side to the side surface 9 on which the convex portion 13 is formed, and a plurality of wave-dissipating blocks 6 are piled up as shown in FIG. In this case, the convex portions 13 and concave portions 14 of adjacent wave-dissipating blocks 6 are configured to fit into each other.

In addition, in the above example, a convex portion 13 is formed on one side surface 9 and a concave portion 14 is formed on the other side surface 11, but as shown in FIG. Convex portions 13 on each
while forming another pair of adjacent side surfaces 1
Recesses 14 may be formed in each of 1 and 12.

A cast iron pipe 15 extending along the length of the block 8 is embedded inside the block 8, and a through hole 16 is formed by the cast iron pipe 15. This through hole 16 has a bellmouth-shaped suction port 18 that opens at the outer end surface 17 of the block 8.
have. Further, a small diameter portion 19 having a smaller diameter than the suction port 18 is formed over a certain length in a portion of the cast iron pipe 15 on the inner side of the bay from the suction port 18 . A large-diameter portion 20 having a larger diameter than the small-diameter portion 19 is formed in a portion of the cast iron pipe 15 on the inner side of the small-diameter portion 19 . The small diameter portion 19 and the large diameter portion 20 are connected via a connecting portion 21, and the connecting portion 21 is formed in a hemispherical shape whose diameter gradually increases from the small diameter portion 19 to the large diameter portion 20. has been done. The large diameter portion 20 has a bay inner end 22
is configured to open at the inner end face 23 of the block 8.

FIG. 4 is a view showing the inside or outside side of a breakwater having a configuration similar to that shown in FIG. 1. As shown, each wave-dissipating block 6 is
They are arranged in a diamond shape when viewed from the end. Between the wave-dissipating block 6 and the base part 1 and between the wave-dissipating block 6 and the upper part 7, there are spacers 2 having a triangular cross section, as shown in FIG.
4 are installed. This spacer 24 is formed with a concave portion or a convex portion that fits into the convex portion 13 or the concave portion 14 of the wave-dissipating block 6, and a fifth
The figure illustrates a spacer 24 in which only a recess 14 is formed.

When constructing an embankment body, first, as shown in FIG. 1, a foundation 1 is formed on the seabed 2, and a plurality of wave-dissipating blocks 6 are stacked on top of this foundation 1. At this time, as shown in FIG. 4, the wave-dissipating blocks 6 are arranged so as to form a rhombus when viewed from the end. Further, the recesses 14 and the projections 13 of adjacent wave-dissipating blocks 6 are fitted into each other. The construction of the embankment body is completed by installing the upper part 7 at the top, but as shown in FIG. Concave portion 14 and convex portion 1
Match with 3.

In this case, as shown in FIG. They are each other's recesses 14
and the convex portion 13 are fitted together, so that the outer side of the bay 4
This prevents it from slipping down. Moreover, the side surface 25 of the breakwater on the outside of the bay will be constructed so as to be inclined toward the seabed 2 side rather than the vertical plane. Also,
Since the wave-dissipating blocks 6 are stacked to form a rhombus shape when viewed from the end, vertical stress transmitted to the lower wave-dissipating block 6 based on the weight of the upper wave-dissipating block 6 is dispersed laterally. be able to. Moreover, it is possible to obtain a large resistance against the buoyant force exerted by waves.

In such a configuration, when waves 26 advance toward the breakwater from the outer side 4 of the breakwater shown in FIG. It collides with the outer end face 17 of the block 8 constructing the breakwater, and energy is absorbed by this collision and the wave is dissipated.

The remaining part of the wave 26 reaches the suction port 18 of the through hole 16. Next, the operation of this remaining part of the wave 26 will be explained based on FIG. 6. That is, the wave 26 that has reached the suction port 18 flows from the suction port 18 to the small diameter portion 1.
At this time, since the suction port 18 is formed in a bullmouth shape, the waves 26 can be introduced into the small diameter portion 19 well. In the small diameter portion 19, the waves 26 collide with the inside of the small diameter portion 19, and their energy is absorbed and subjected to a wave-dissipating action, and then the connecting portion 21 is guided to the large diameter portion 20.

Then, due to the increase in the passage cross-sectional area from the small diameter portion 19 to the large diameter portion 20, the fluid energy possessed by the waves 26 is absorbed and wave dissipation is performed. Further, waves 26 generate vortices 27 in the large diameter portion 20, and energy is consumed to generate these vortices 27, thereby dissipating waves. Furthermore, waves are also dissipated by collision with the inner surface of the large diameter portion 20. Finally, the wave 26 is connected to the large diameter portion 20
The waves are guided from the inner end 22 of the bay to the inner bay 5, where they are also dissipated by increasing the cross-sectional area of the passage.
It will be in a state where it has almost no energy.

When the waves 26 pass through the through hole 16 in this manner, a water flow toward the inner side 5 of the bay is generated inside the through hole 16. Furthermore, when the waves 26 return to the outside 4 of the bay, the through hole 16 is inclined downward toward the outside of the bay.
Water existing inside the bay flows out toward the outside 4 of the bay.

As a result, water always flows inside the through-hole 16, allowing good water circulation between the inside and outside of the bay. In addition, the through hole 16
Even if foreign matter gets inside the
These impurities are discharged to the outer side 4 or the inner side 5 of the bay along with the water flow inside the through hole 16, and are prevented from staying inside the through hole 16.

The angle of inclination of the wave-dissipating block 6 is preferably in the range of 2 to 10 degrees; if it is less than 2 degrees, it will be in a nearly horizontal state and no substantial effect can be expected. Moreover, if it exceeds 10 degrees, the suction of the waves 26 from the suction port 18 will be poor, so it will still lack effectiveness.

As mentioned above, since the side surface 25 of the breakwater on the outside of the bay is constructed to be inclined toward the seabed 2 side rather than the vertical plane, when the waves 26 collide with this side surface, the waves 26 are It also has the effect of being able to return to the outside of the bay 4 as shown by arrow A in Figure 1. Furthermore, in the wave-dissipating block 6 installed at a height corresponding to the water surface 28, air enters the through-hole 16 along with the waves 26, so there is also a wave-dissipating effect based on the mixing of this air.

Incidentally, since the through hole 16 is formed of the cast iron pipe 15, the wave dissipating block 6 can be easily formed by pouring concrete around the cast iron pipe 15, and the block 8 can be reinforced by the cast iron pipe 15. can do.

FIG. 7 shows a cross-sectional view of another embodiment of a breakwater according to the invention. In this embodiment, a through hole 16 formed inside the block 8 is used.
is formed so that the through holes 16 shown in FIGS. 1 and 2 are arranged almost mirror-symmetrically.
That is, the through hole 16 has a large diameter portion 20 formed longer than that shown in FIG. 1, followed by a second connecting portion 29 and a second small diameter portion 30. The small diameter portion 30 of the block 8 has a bay inner end surface 2.
A discharge port 31 opening at 3 is formed.

With this configuration, the through hole 16 can be made longer than those shown in FIGS. 1 and 2, and the number of changes in its cross section can be increased, so that the wave dissipation effect can be greatly improved. Can be done.

Effects of the Invention As described above, according to the present invention, it is possible to reliably dissipate waves using the through hole provided in the block, and furthermore, as the waves advance inside the through hole, the inside of the through hole becomes a bay. In addition to generating an inward water flow, the through holes are installed at an angle, so when the waves return to the outside of the bay, a water flow is generated toward the outside of the bay, resulting in good water circulation inside and outside the bay. In addition, contaminants can be prevented from staying inside the through hole.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an embodiment of a breakwater according to the present invention, FIG. 2 is a diagram showing a wave absorption block used in constructing the breakwater shown in FIG. 1, and FIG.
The figure shows another example of the same block.
5 is a side view of a breakwater similar to the breakwater shown in FIG. 5. FIG. 5 is a diagram showing spacers used in constructing the breakwater shown in FIG. FIG. 7 is a cross-sectional view of another embodiment of a breakwater according to the invention. 4... Outside the bay, 5... Inside the bay, 6... Wave absorption and dissipation block, 16... Through hole, 18... Absorption port, 19... Small diameter part, 20... Large diameter part.

Claims (1)

[Claims] 1. A through hole is formed in the length direction, having a suction port on the outside of the bay, a small diameter portion formed on the inside of the bay from the suction port, and a large diameter portion formed on the inside of the bay from this small diameter portion. A breakwater characterized by a plurality of pillar-shaped wave absorbing and dissipating blocks arranged horizontally and stacked on top of each other in an upward slope from the outside of the bay to the inside of the bay.