JPH0468106A - Diagonal wave dissipation type breakwater - Google Patents

Abstract

PURPOSE:To improve capability of wave dissipation by a method wherein a breakwater main body, stretching horizontal and having a slope facing the direction from which waves approach, and a breakwater equipped with partitions, some of which have openings and others do not, are provided and a recessed part for producing of diagonal waves is provided on the offshore side along the longitudinal direction of the breakwater. CONSTITUTION:A breakwater 6, stretching horizontal and having a slope that faces the direction C from which waves approach, is arranged. A diagonal wave producing recessed part 7 is provided to the ground 2 on the offshore side so that it gradually extends in the width along the longitudinal direction of the breakwater 6, and thereby the waves progressing toward the breakwater alter the course, and waves diagonal to the breakwater 6 are produced therewith. Projections and recesses provided to the breakwater 6, and openings 3 for passing through of diagonal waves provided to partition walls 4 with openings of the breakwater 6 make the diagonal waves reflected and collide with the following waves. The waves progressing diagonally in the projections and recesses of the breakwater 6 meet with resistance when passing through the openings 3 and lose energy thereby, as well as by colliding with the following waves.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention utilizes the energy of waves acting on the surface of a breakwater to
This invention relates to a diagonal wave-dissipating breakwater that can attenuate waves by collision with each other.

[Conventional technology]

In breakwaters installed in coastal areas, various measures have been taken to weaken the wave force acting on the surface. Conventionally,
The most popular type of breakwater is one with a rectangular cross section. This breakwater can prevent waves from propagating into the inland sea by reflecting waves from the open sea.

[Problem to be solved by the invention]

In the case of the conventional breakwater, the energy of large waves acts directly on the breakwater, causing the breakwater to overturn, and the waves that hit the breakwater are reflected and interact with subsequent waves, causing high waves. This may significantly increase the amount of water, which may impede the safe navigation of ships.

Despite the above-mentioned drawbacks, breakwaters with a rectangular cross section are often used because their simple shape is valued for their economic efficiency and ease of construction.

An object of the present invention is to provide a diagonal wave-dissipating breakwater that has a simple shape but can exhibit great wave-dissipating performance.

[Means to solve the problem]

In order to achieve the purpose of serious crime, in the oblique wave dissipating breakwater of the present invention, a breakwater main body 1 that is inclined with respect to the direction of wave propagation and extends laterally is installed on the seabed ground 2'', and the breakwater main body 1 A partition wall 4 with an opening, which projects in the direction of wave propagation and is provided with an opening 3 for passing diagonal waves, and a non-opening partition wall 5, which projects in the direction of wave propagation and is not provided with an opening, are disposed on one wall surface of the partition wall. , the breakwater main body 1, the partition wall 4 with openings, and the partition wall 5 without openings are arranged alternately at intervals in the longitudinal direction of the breakwater main body and are integrally provided.
A diagonal wave generating recess 7 whose width gradually increases along the longitudinal direction of the breakwater 6 is provided on one side of the breakwater 6 .

〔Example〕 Next, the present invention will be explained in detail using illustrated examples.

1 to 6 show a diagonal wave-dissipating breakwater according to an embodiment of the present invention, in which a concrete breakwater main body 1 is inclined with respect to the wave traveling direction C and extends laterally.
is placed on the seabed ground 2'', and on one side wall of the breakwater body 1, there is a concrete 1/split section that protrudes in the direction of wave propagation and is provided with a diagonal wave passage section 3. A partition wall 4 and concrete non-opening partition walls 5 which protrude in the direction of wave propagation and have no openings are integrally arranged and arranged alternately at intervals in the longitudinal direction of the breakwater main body, and are integrally provided. A breakwater 6 is constituted by the main body 1, the partition wall 4 with openings, and the partition wall 5 without openings.

A foundation rubble layer 8 made of chestnut stone is provided on the land side of the dug-out depression in the seabed ground 2, and a covering layer 9 made of concrete blocks is laid on the horizontal upper surface of the rubble layer 8. A scour prevention layer 10 made of concrete blocks is placed on the offshore slope of A diagonal wave generating recess 7 whose width gradually increases along the longitudinal direction is provided.

In general, wave speed is proportional to the square root of water depth, so by excavating the breakwater 6 so that its width gradually increases along the length of the breakwater 6 and providing the four parts 7 for generating oblique waves, as described above,
It is possible to generate oblique waves against the breakwater 6 by refracting the traveling direction of waves.

The oblique waves generated in this way collide diagonally with the uneven surface of the breakwater 6, and due to the reflection of the waves in the concave portions of the breakwater 6, the waves collide with each other and the wave energy is attenuated. Waves entering the recess from an oblique direction pass through the diagonal wave passage volume in the bulkhead 4 with the opening 11 due to the pressure difference within the recess of the breakwater 6, and the wave is also prevented by the flow resistance during the passage. energy is attenuated.

Furthermore, the ice block that has entered one recess and then moved to the other recess through the diagonal wave passage opening 3 moves toward one side within the recess, and the ice block and the wave that directly enters the other recess are combined. During this time, a phase difference occurs due to the time difference, and the energy of the wave is also attenuated by the collision between the ice block and the following wave due to this phase difference.

When carrying out this invention, when the wave height, wavelength and period are large, the interval between the partition wall 4 with openings and the partition wall without openings is set large, and when the wave height is large and the wavelength and period are short, oblique waves are passed. The size of the opening 3 is set large.

〔Effect of the invention〕

Since this invention is configured as described above, it produces the effects described below.

Waves traveling toward the breakwater 6 are refracted at the upper part of the diagonal wave generating recess 7 to generate diagonal waves, and the diagonal waves are directed toward the breakwater 6.
The reflected wave can be reflected by using the unevenness and the oblique wave passage opening 3, and the reflected wave can collide with the following waves,
In addition, waves that enter the recess of the breakwater 6 from an oblique direction are subjected to flow resistance when passing through the diagonal wave passage opening 3, and the ice blocks that have passed through the diagonal wave passage opening 3 collide with the following waves. Therefore, it is possible to exhibit great wave-dissipating performance by using the breakwater 6 with a simple shape.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a plan view of a diagonal wave-dissipating breakwater, Fig. 2 is a front view thereof, and Fig. 3 is an enlarged view of line A-A in Fig. 1. 4 is an enlarged sectional view taken along the line B-B in FIG. 1, FIG. 5 is a perspective view of the breakwater, and FIG. 6 is a longitudinal side view showing the installed state of the diagonal wave-dissipating breakwater. In the figure, 1 is the breakwater main body, 2 is the seabed ground, 3 is a section for passing diagonal waves, 4 is a bulkhead with openings, 5 is a bulkhead without openings, 6 is a breakwater, 7 is a recess for generating diagonal waves, 8 9 is a foundation rubble layer, 9 is a covering layer, and 10 is a scour prevention layer.

Claims (1)

[Claims] A breakwater main body 1 that extends horizontally and inclines with respect to the direction of wave propagation is installed on the seabed ground 2, and an opening 3 for passing diagonal waves that protrudes in the direction of wave propagation is provided on the offshore wall of the breakwater main body 1. The bulkheads 4 with openings and the non-opening bulkheads 5 that protrude in the direction of wave propagation and have no openings are arranged alternately at intervals in the longitudinal direction of the breakwater main body and integrated. A diagonal wave generating recess 7 whose width gradually increases along the longitudinal direction of the breakwater 6 is provided on the offshore side of the breakwater 6, which is formed of the breakwater main body 1, a bulkhead 4 with an opening, and a bulkhead 5 without openings. A diagonal wave-dissipating breakwater.