JPH063003B2 - Breakwater - Google Patents

Description

TECHNICAL FIELD The present invention relates to a breakwater provided on a shore or the like.

(Prior Art) Conventionally, as this type of breakwater, one using a rubble or a deformed concrete block is known. Also, as a construction method of water structures such as breakwaters, piles are driven into the seabed,
A method is known in which a deformed wave-dissipating block is inserted from the bottom of the sea to the surface of the pile and the upper end of the pile on the water is connected by a tie material (JP-A-60-3308).

(Problems to be Solved by the Invention) The conventional breakwater using the rubble and the deformed concrete block has problems in terms of the wave breaking effect, the construction cost, and the landscape, and further has a gravity structure by direct support. Therefore, there is a risk of sinking collapse due to scouring, and if the seabed is steep,
There are also problems with stability. As described above, the structure in which the odd-shaped wave-dissipating block is inserted into the pile driven into the seabed is in large communication in the up-down direction from the seabed to the sea surface, so the wave energy is transmitted vertically and its wave-dissipating effect is increased. not enough.

An object of the present invention is to provide a breakwater which has a sufficient wave-dissipating effect, is easy to construct, and does not damage the landscape.

(Means for Solving Problems) In the present invention, a support member is attached below a plurality of piles driven into the ground in water, and a spacer provided with one insertion hole below the piles. A concrete block and a beam concrete block having a plurality of insertion holes are loosely fitted to the piles through the insertion holes and stacked on the support member to provide a slit structure portion, and above the slit structure portion and At a position below the water surface, by providing a horizontal plate structure portion that forms a substantially series of horizontal surfaces below the water surface by inserting a slab concrete block having a large plane area with an insertion hole into the pile body through the insertion hole, The above-mentioned purpose is achieved.

(Function) In the deep water area, in the slit structure part, reflection by spacer concrete block and beam concrete block, turbulence due to shape resistance of these blocks, energy loss due to turbulent flow in the water retaining part surrounded by slits, etc. Is lost by. In addition, the shallow water region is divided into upper and lower parts in the horizontal plate structure, and the horizontal plate reflects waves on the horizontal plane, is disturbed by the collision of traveling waves and retrograde waves, and travels on the horizontal plane including waves after breaking waves. The wave is dissipated by the vortex due to the phase difference between the wave and the traveling wave under the horizontal plane, and the energy transfer above and below the wave is reduced by the horizontal plane, and the wave is segmented and efficiently dissipated.

(Example) Next, an example of the present invention will be described with reference to the accompanying drawings.

1 to 3 show one embodiment of a breakwater according to the present invention, in which reference numeral 1 denotes a steel columnar pile body driven into the ground 2 on the seabed. , The pile 1 is, as shown,
1 row and 6 rows were arranged in the lateral direction toward the drawing so as to be arranged in the 3 rows in the vertical direction, and the support member 3 was attached to the lower side of each pile body 1 and slightly above the ground 2. The support member 3
Although not shown in the figure, the fixing device was used to fix the pile body 1.

A concrete block was inserted into each pile body 1 to form a slit structure portion 9 below the pile body 1 and a horizontal plate structure portion 11 above and below the water surface. The slit structure portion 9 is formed by integrally molding a columnar spacer concrete block 4 having a through hole 5 having a diameter larger than the diameter of the pile body 1 at the center and the spacer concrete block 4 at both ends of the connecting rod 7. By alternately inserting the beam concrete block 6 formed into the pile body 1 in a loosely fitted state,
It was formed in a slit-shaped opening through which seawater flows. Further, the horizontal plate structure portion 11 has the same insertion hole 5 as that described above in the pile body 1.
The square plate-like slab concrete block 8 having a large plane area and having a large planar area is inserted through the slab concrete block 8 in a loosely fitted state and the blocks 8 are brought into direct contact with each other to be aligned, thereby arranging the slit structure portion 9 A series of horizontal planes 10 was formed above.

In the example of the first illustration, two slab concrete blocks 8 are inserted above and below each pile body 1 via a spacer concrete block 4 to form two horizontal planes 10 in the upper and lower directions, and further, the traveling direction of the wave. The central portion of the connecting rod 7 of the beam concrete block 6 on the side orthogonal to is bulged up and down. These concrete blocks 4, 6 and 8 are fixed by tightening them up and down by using not-shown tension material as needed, and further filling the gaps between the respective through holes 5 and the pile body 1 with grout material. The concrete blocks 4, 6 and 8 were integrated with each other to increase the strength of the breakwater.

A spacer concrete block 4 is provided at the upper end of the pile body 1.
A horizontal plate portion 12 made of cast-in-place concrete was provided via the above to support the upper end of the pile body 1. Reference numeral 13 is the water surface.

In this embodiment, when water particles pass through the breakwater, the deep water region passes through the slit structure portion 9, and the shallow water depth region passes through the horizontal plate structure portion 11. Then, a part of the traveling wave collides with the side surface of the spacer concrete block 4 and the side surface of the beam concrete block 6 and is reflected, or the flow is disturbed by the shape resistance of these blocks, and in the water retaining portion surrounded by the slit, It becomes a turbulent flow and the wave energy is consumed, and the wave-dissipating effect is exerted. Further, in the horizontal plate structure portion 11, the traveling wave entering there collides with the side surfaces of the spacer concrete block 4 and the upper and lower surfaces of the slab concrete block 8 and is reflected, and the flow is disturbed by the shape resistance of these blocks,
The traveling wave and the horizontal plane which are broken on the horizontal plane 10 and further the retrograde wave collides with the traveling wave on the horizontal plane 10 to reduce the energy of the traveling wave, and which has passed through the horizontal plane structure portion 11 when passing through the horizontal plane 10. A phase difference is generated between the traveling waves that have passed under 10 to generate a vortex, and in particular, the horizontal plane 10 blocks the energy transfer in the vertical direction of the waves to supply energy to the traveling waves on the horizontal plane 10. Since it is cut off, the energy loss of the wave passing above the horizontal plane 10 becomes effective, and as a result, the wave-dissipating effect is increased.

As shown in FIGS. 4 to 6, the slab concrete blocks 8 may be arranged horizontally with some gaps 14 therebetween, and in this case, some upward and downward flows are generated through the gaps 14. However, this flow becomes a jet and consumes energy, and since it has vertical energy, it acts to disturb the traveling wave and attenuates the traveling wave to extinguish it.

Wave-dissipating effect of Shonamitsutsumi is represented by energy loss rate of the wave passing through the Shonamitsutsumi ^{_{K L 2 (= 1-K}} T 2 -K R 2), the loss rate, transmits Shonamitsutsumi The value obtained by dividing the transmitted wave height H _T by the incident wave height H _I incident on the breakwater: _KT and the value obtained by dividing the reflected wave height H _R reflected by the breakwater by the incident wave height H _I : Determined by K _R. It is also known that this loss rate varies with the relative width B / L obtained by dividing the width of the breakwater: B by the wavelength: L.

According to the experiment, the breakwater having only the slit structure portion 9 without the horizontal plate structure portion 11 has a relative width B / L of about 0.25 and an energy loss rate K _L ² of about 0.5, which is a maximum value. Although the wave-dissipating effect is large for a specific wavelength and the wave-dissipating effect is low for wavelengths other than the specific wavelength, the first aspect of the present invention
In the breakwater constructed as shown in Fig. 2 and Fig. 2, the energy loss rate K _L ² becomes at least about 0.5 and the relative width B
The energy loss rate K _L ² gradually increases with an increase in / L. In other words, it can be seen that the horizontal plate structure portion 11 can provide a large wave canceling effect for various wavelengths. It was. Further, in the configurations of FIGS. 4 and 5 of the present invention, in the experiment, the change of the energy loss rate with respect to the change of B / L showed a tendency similar to that of the configuration of FIG. The illustration shows the slab concrete block 8
Is not a series but is segmented to such an extent that the horizontality is not impaired, so that there is an advantage that the construction is easy and the up and down flow is generated through the void 14, and the force that the breakwater receives from the wave can be reduced.

The slit structure part 9 and the horizontal plate structure part 11 are not limited to those of the above-mentioned embodiment, but the shape, arrangement, etc. of the concrete blocks 4, 6, 8 are variously changed to suit the type of wave and the terrain. It can be constructed on a breakwater.

(Effects of the Invention) As described above, the breakwater of the present invention is provided with the slit structure portion formed of the spacer concrete block and the beam concrete block below the plurality of piles driven into the ground, and above the pile structure. Since the slab concrete block is arranged horizontally below the horizontal surface to provide the horizontal plate structure section having the horizontal plane, the wave is divided at the horizontal plane as a boundary, the energy transfer above and below the wave is blocked, and Since the slit structure portion and the horizontal plate structure portion each independently wave-dissipate, the wave-dissipating effect is improved.

[Brief description of drawings]

FIG. 1 is a front view of one embodiment of the breakwater of the present invention, FIG. 2 is a side view of FIG. 1, and FIG. 3 is a sectional view taken along the line III-III of FIG.
FIG. 4 is a front view of another embodiment of the present invention, FIG. 5 is a side view of FIG. 4, and FIG. 6 is a sectional view taken along the line IV-IV of FIG. 1 ... Pile body 2 ... Ground 3 ... Supporting member 4 ... Spacer concrete block 5 ... Insertion hole 6 ... Beam concrete block 8 ... Slab concrete block 9 ... Slit structure part 11 ... Horizontal plate structure part

 ─────────────────────────────────────────────────── ─── Continuation of front page Examiner Yoko Watanabe (56) References JP-A-60-3308 (JP, A)

Claims (1)

[Claims] 1. A support member is attached below a plurality of piles that are driven into the submerged ground, and a spacer concrete block having one insertion hole and a plurality of insertion holes are provided below the piles. Slit structure blocks are provided by loosely fitting the beam concrete blocks into the piles through the insertion holes and stacking them on the support member, and the insertion holes are provided above the slit structure parts and below the water surface. A breakwater, characterized in that a horizontal plate structure portion is provided which forms a substantially continuous horizontal plane below the water surface by inserting a slab concrete block having a large plane area into the pile through the insertion hole.