JPH0941341A - Breakwater with seawater exchange function - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To secure the calmness in a harbor,
The aim is to realize a seawater exchange-type breakwater with sufficient seawater exchange. According to the present invention, an outside port is provided through an opening 11a provided on a front wall 11 and opened above and below the sea level, and an opening 12a provided on a rear wall 12 and opened below the sea level. In a breakwater with a seawater exchange function in which a water reservoir 13 that communicates with the seawater of the port 1 and the harbor 2 is formed inside the dam body 10 and the superstructure is projected above the sea surface, the water breaker chamber 13 faces the rear wall 12 toward the rear wall 12. An inclined wall 5 having a rising slope 5a was provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a breakwater constructed in a harbor, a fishing port, etc. More specifically, it is possible to introduce seawater outside the harbor into the harbor while ensuring the quietness inside the harbor surrounded by the breakwater. The present invention relates to a breakwater having a transparent seawater exchange function.

[0002]

2. Description of the Related Art Generally, since breakwaters have been constructed with an emphasis on securing the quietness in the port, they often have a strong closing property and poor exchangeability of seawater inside and outside. Therefore, in order to ensure the clean water quality of the seawater in the port, it has been conventionally attempted to improve the seawater exchange throughout the port while ensuring quietness in the port by using a breakwater as a permeable structure. However, in this way, the problem of antinomy has to be established at the same time, and a problem remains in terms of efficiency.

Recently, multipurpose breakwaters of various structural types have been researched and developed, and some of them have already been implemented, while maintaining the original breakwater function of the breakwater and promoting the exchange of seawater in the port. For example, in a relatively shallow water area, a structure has been developed in which a submerged dike is provided in front of the harbor outside of a breakwater with an opening for water transmission. The principle of the introduction of seawater outside the port with this submerged dike is as follows.

The wave traveling from the offshore side toward the breakwater is forcibly broken on the submerged breakwater, and the wave after breaking causes a rise in the water level, and as a result, an increase in the average water level in the water retaining section occurs. Due to the water level difference between the inside and outside of the port thus generated, water is conducted from the outside of the port to the inside of the port. However, such a structure type has an economical difficulty because the construction cost increases as the water depth increases.

On the other hand, upright transmission type breakwaters are often used in deep waters. This type of conventional upright transmission type breakwater is shown in FIG. 9 and its operation is shown in FIG. In FIG. 9, 1 is outside the port, 2 is inside the port, 3 is a breakwater, and 11 is outside the port 1
Side front wall, 12 is a rear wall, and the openings 11a, 12 are respectively
a is provided, and a water retaining chamber 13 is formed between the front wall 11 and the rear wall 12. Then, the opening 1 of the rear wall 12
2a reduces the transmission wave to the 2nd side of the harbor, so the front wall 11
The aperture ratio is smaller than that of the opening 11a.

[0006]

In a breakwater having a structure as shown in FIG. 9 which is used in a place where the water is relatively deep, as shown in FIG. At the opening 12a of the rear wall 12, the water flows at a high flow velocity due to the head difference from the side and the hydrodynamic pressure of the traveling wave. On the other hand, at the time of backwash, the water level in the water retaining chamber 13 becomes lower than that in the harbor 2 side, and the head difference causes a flow from the harbor 2 side to the harbor 1 side. As a result, since the flow velocity flowing into the harbor 2 side is faster on average, seawater will be introduced to the harbor 2 side accordingly.

As described above, near the harbor 2 side of the breakwater 3, a rapid flow occurs at the time of pushing waves, and the wave height transmitted to the harbor 2 side becomes high, which may hinder towing or mooring of the ship. Therefore, if the opening ratio of the rear wall 12 is lowered, there is a problem that the water is not sufficiently guided to the port 2 side and the seawater exchange is not promoted.

The present invention has been made to solve the conventional problems as described above, targeting a breakwater used in a place where the depth of water is comparatively deep. The strong flow is eliminated to ensure the quietness in the port. At the same time, the purpose is to provide a seawater exchange type breakwater in which seawater exchange is sufficiently performed.

[0009]

[Means for Solving the Problems]

(1) A breakwater having a seawater exchange function according to the present invention has an opening provided on a front wall and opened above and below the seawater level,
Through the opening provided on the rear wall and opening below the sea level,
A breakwater with a seawater exchange function that forms a water storage chamber that communicates with the seawater outside and inside the harbor inside the levee body, and has a slope that rises toward the rear wall in the water basin that has a seawater exchange function with the superstructure protruding above the sea surface. A slanted wall is provided. (2) Further, the breakwater of the above (1) is provided with a plurality of water retaining chambers provided with inclined walls having different submerged heights corresponding to the tide level change of the sea level.

The inclined wall provided in the water retaining chamber further divides the water retaining chamber into a front chamber and a rear chamber. Therefore, at the time of pushing wave, the water level rises in the rear chamber partitioned by the rear wall and the inclined wall by the inclined wall in the water retaining chamber. Therefore, water is introduced into the port due to the difference in water level between the seawater inside the rear chamber and the seawater inside the port.

On the other hand, the water level on the anterior chamber side between the inclined wall and the front wall lowers when the wave is pulled, but the water level in the rear chamber between the inclined wall and the rear wall hardly decreases. Therefore, there is no return flow of seawater inside the port to the outside of the port. Therefore, due to the flow action of the pushing wave and the pulling wave, the seawater outside the port is introduced into the port as a unidirectional flow toward the inside of the port at the opening of the rear wall.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment Next, a first embodiment of the present invention will be described with reference to the drawings.
1 is a perspective view of a breakwater having a seawater exchange function according to a first embodiment of the present invention. The constituent parts shown in the drawings of the present embodiment are designated by the same reference numerals as those in the prior art described in FIGS. 9 and 10, and a part of the description will be duplicated, but will be described in some detail.

In FIG. 1, 1 is the outside of the harbor, 2 is the inside of the harbor, 3 is a breakwater that separates the outside 1 and the inside 2 of the harbor, and 4 is seawater. 10
Is a breakwater body of the breakwater 3, 11 is a front wall, 12 is a rear wall (hereinafter, the outside 1 side is referred to as the front wall 11, the inside 2 side is referred to as the rear wall 12), and 13 is between the front wall 11 and the rear wall 12. The formed water retaining chamber, 14 is a superstructure. Reference numeral 11a is a plurality of slit-shaped openings provided in the height direction of the front wall 11, and 12a is a similar opening provided in the rear wall 12. As shown in the figure, the opening 11a on the front wall 11 side is formed long from below the sea level to above the sea level, but the opening 12a on the rear wall 12 side is provided below the sea level and the low tide. It is formed at a low position so that it may be submerged even at times and has a small aperture ratio.

Reference numeral 5 denotes an inclined wall provided inside the water retaining chamber 13, 5a an inclined surface of the inclined wall 5, and 6 an ocean surface. Slope 5
a is formed on the front surface of the inclined wall 5 from the base portion to the top portion (submerged surface) of the front wall 11 so that the inclination angle θ increases toward the rear wall 12. The top of the inclined wall 5 is formed to have a height that is close to the average water level of the tide level of the seawater 4. Reference numerals 13a and 13b denote a front chamber and a rear chamber, which are formed by partitioning the water retaining chamber 13 with the inclined wall 5, and have vertical cross-sectional shapes of a triangle and a rectangle, respectively.

The operation of this embodiment having the above-mentioned structure is
It will be described next with reference to FIG. A part of the waves pushed toward the breakwater 3 from the offshore of the harbor 1 enters the water retaining chamber 13 inside the levee body 10 through the opening 11 a of the front wall 11.
As shown in Fig. 2 (a), the pushing wave that has entered the water retaining chamber 13 is
The water flows from the front chamber 13a into the rear chamber 13b to raise the water level in the rear chamber 13b. For this reason, a water level difference occurs between the water retaining chamber 13 and the sea level 6 of the harbor 2, and water is conducted to the harbor 2. In this case, the water level rise in the rear chamber 13b is effectively performed by the contraction effect of the slope 5a of the pushing wave.

On the other hand, the water level of the antechamber 13a provided on the outside of the port 1 side of the inclined wall 5 is lowered during the wave pulling, as shown in FIG. 2 (b). However, since the inclined wall 5 is provided, the water level in the rear chamber 13b hardly drops, so that the return flow of the seawater 4 from the port 2 does not occur. Therefore, due to the interaction between the pushing wave and the pulling wave, a unidirectional flow of seawater toward the inside of the harbor 2 occurs at the opening 12 a of the rear wall 12. As a result, the clean seawater 4 outside the port 1 is introduced into the port 2. Then, the seawater staying in the harbor 2 flows out of the harbor to the outside of the harbor, and the seawater is effectively exchanged.

(Example) Next, an example of the present embodiment will be described. The experimental equipment is as shown in FIG. 3, and the function and effect of the present invention were confirmed by a model reduced to approximately 1/30. In FIG. 3, 21 is a wave-making water channel, 22 is a model of a breakwater, and 23 is a wave-making device. Also, 24 is a current meter, 25
Is a wave height meter and 26 is a wave-dissipating beach. Anemometer 24
Is provided near the rear side 12 of the model 22 on the inside 2 side of the port, and the wave height meters 25 are installed at two locations outside the port 1 and at one location inside the port 2.

As shown in FIG. 4, a model 22 of the breakwater 3 of this embodiment is installed in a wave-making water channel 21 having a water depth of 57.4 cm. Wave-making device 23 at one end of the wave-making water channel 21
Waves were generated at 1, and the flow velocity v was measured by the flow velocity meter 24 provided on the 2nd side of the port. In addition, the wave height transmissibility (KT) was also measured with the wave height meter 25 installed at three locations. For comparison, an experiment was also conducted on the conventional model M. The specifications of model M are shown in Fig. 4 (b).

Next, an example of the measurement result of the flow velocity by the above experiment is shown in FIG. The model 22 of the present invention always has a unidirectional flow toward the inside of the port, as indicated by the waveform curve C1 represented by the dotted line in FIG. 5 (a). On the other hand, the waveform curve C2 of the conventional model M has a flow that alternately flows into the port 1 and the port 2 as shown in FIG. 5 (b). And since the maximum flow velocity to the port 2 side is smaller in the present invention, the flow generated on the port 2 side is smaller,
The impact on vessel towing and mooring is also small.

FIG. 6 shows an example of the result of measuring the crest transmissibility (KT) by the three crest meters 25. Model 22 of the present invention
Compared with the conventional model M, the wave height transmissibility (KT)
It can be seen that the tranquility of Port 2 is kept smaller because of the small.

FIG. 7 shows the dimensionless amount of water transfer obtained from the average value of the flow velocity in order to make a clear comparison of the amount of water transfer to the port 2 side. 7 (a) and 7 (b) are examples of measurement results of different wave heights. The dimensionless amount of water transfer is defined by the following equation. Dimensionless water flow (Q / Q0) = (Water flow to the port 2 side due to waves / Maximum flow in the port 2 direction due to waves outside the port 1) As is clear from Fig. 7, the present invention is more conventional. It was confirmed that a large amount of water was introduced to the 2nd side of the harbor.

Embodiment 2 FIG. 8 is a perspective view of Embodiment 2 of the present invention. The breakwater body 10 of the breakwater 3 of the present embodiment is formed with a plurality of water retaining chambers 31, 32, 33, ... Partitioned by horizontal partition walls 30, and each of the water retaining chambers 31, 32, 33 ,. , Inclined walls 51, 52, 53, ... With different heights of the submerged surface are provided.

Since the effect is maximized when the height of the inclined walls 51, 52, 53, ... Is near the sea level, for example, the height of the submerged surface of the inclined wall 51 is set to the sea level at high tide. The heights of the submerged surfaces of the slanted walls 52 and 53 are made to coincide with each other, and the heights of the submerged surfaces of the slanted walls 52 and 53 are made to match the sea level at the average tide level and the sea level at low tide, respectively. With this configuration, the seawater 4 outside the port 1 is always and effectively introduced into the port 2 even if the tide level changes, and a more effective seawater exchange function can be achieved.

In the drawings of each of the above-described embodiments, the case where the slope is formed on the front surface of the sloped wall from the base of the front wall to the top of the sloped wall has been described, but the slope is set up in the water storage chamber. It may be provided up to the middle of the upper wall.

[0025]

【The invention's effect】

(1) The breakwater having a seawater exchange function according to the present invention has an opening provided on the front wall and opened above and below the seawater level, and an opening provided on the rear wall and opened below the seawater level. In the breakwater with a seawater exchange function that forms a water storage chamber inside the levee body that communicates with seawater outside and inside the harbor, and the superstructure projects above the sea surface, the slope that rises toward the rear wall in the water storage chamber An inclined wall having As a result, the water level of the part partitioned by the rear wall and the inclined wall rises due to the inclined wall in the water retaining chamber during the pushing wave, and water is introduced due to the difference in water level with the inside of the port. On the other hand, at the time of backwash, the water level on the outside of the sloping wall decreases, but the water level on the inside of the sloping wall does not decrease, and no return flow from the inside of the port occurs. Therefore, due to the action of the waves, a one-way flow toward the inside of the port is made at the opening, and seawater outside the port is introduced into the inside of the port.

(2) Further, in the breakwater having the seawater exchange function of the above (1), since a plurality of water retaining chambers provided with inclined walls having different submerged heights are provided corresponding to seawater tide level fluctuations, the harbor is always available. Outside seawater can be effectively introduced inside the port.

Therefore, according to the present invention, it is possible to obtain a seawater exchange type breakwater in which the calmness in the port is ensured and the seawater is sufficiently exchanged.

[Brief description of drawings]

FIG. 1 is a perspective view illustrating a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the operation of the first embodiment of the present invention.

FIG. 3 is a schematic diagram showing a configuration of an experimental device to which the first embodiment of the present invention is applied.

FIG. 4 is an explanatory diagram showing main specifications of the experimental equipment of FIG.

FIG. 5 is a comparison diagram of flow velocities of the first embodiment of the present invention and a conventional device.

FIG. 6 is a comparison diagram of the reflectance and the crest transmissivity of the first embodiment of the present invention and the conventional device.

FIG. 7 is a comparison diagram of the dimensionless water transfer amount between the first embodiment of the present invention and the conventional device.

FIG. 8 is a perspective view showing a configuration of a second exemplary embodiment of the present invention.

FIG. 9 is a perspective view showing a configuration of a conventional breakwater.

FIG. 10 is a cross-sectional view showing the action of a conventional breakwater.

[Explanation of symbols]

 1 Outer Port 2 Inside Port 3 Breakwater 4 Seawater 5 Sloping Wall 5a Slope 6 Sea Surface 10 Levee Body 11 Front Wall 11a Front Wall Opening 12 Rear Wall 12a Rear Wall Opening 13 Water Reservoir 13a Front Room 13b Rear Room 30 Horizontal Bulkhead 31 , 32 ... Water retaining chamber 51, 52 ... Inclined wall

Claims (2)

[Claims] 1. The outside of the harbor and the inside of the harbor are communicated with each other through an opening provided on the front wall and opening above and below the sea level and an opening provided on the rear wall and opening below the sea level. A breakwater having a seawater exchange function in which a water retaining chamber is formed inside a dam body and a superstructure projecting above the sea surface, wherein an inclined wall having a slope increasing toward the rear wall is provided in the water retaining chamber. A breakwater with a seawater exchange function. 2. The breakwater having a seawater exchange function according to claim 1, further comprising a plurality of water-retaining chambers provided with inclined walls having different submerged heights corresponding to the tide level fluctuations of the seawater level.