JPS62117905A - Sea water-crossed breakwater - Google Patents

Abstract

PURPOSE:To prevent the propagation of wave pressure to the inside of a port for activating the action of automatic depuration by providing a breakwater having a water storage tank opened toward the outside of a port and a water conveyance path opened toward the bottom inside the port. CONSTITUTION:By introducing overflow water 10 of tidal wave 9 outside of a port 3 through a water conveyance path 12 into the port 4 by water head H produced in a water storage tank 11 by means of a breakwater 1, the direct propagation of wave pressure to the inside of the port 4 can be avoided. The dissolved oxygen amount in sea water is increased by the turbulent flow of the tidal waves 9 coming into the tank 11, the overflow water 10 with rich dissolved oxygen flows into the bottom layer in the port 4 to form an aerobic state, and thereby the automatic depuration of sea water is activated. Also, in the summer season, the overflow water of the tidal waves in high-temperature surface layer flows into the low-temperature bottom layer in the port 4 to form a convectional flow in the vertical direction in the port 4, and the crossing of sea water in the port 4 is accelerated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a seawater exchange breakwater that exchanges seawater outside a port into a port.

(Conventional technique #r4) The Japanese coastline is roughly divided into three types: coastal areas facing the open sea, full open areas, inland seas, and closed inner bays. Especially full of openings,
In inland seas and closed inner bays, due to their natural topography,
Because the natural conditions such as waves are gentle, it has been used in advanced ways for a long time.

It is widely known that landfills, coastal factories, and ports are concentrated in these areas, and the problem of seawater pollution has become increasingly serious.

Currently, drainage regulations have been enforced, and seawater purification is gradually progressing, but in closed areas such as harbor areas, the quality of stagnant water is still deteriorating. In addition, in the fishing industry, with the establishment of a 200 nautical mile zone in recent years, the type of fishing has been changing from far-sea to offshore to coastal fishing, and a number of fisheries are being installed within fishing ports. . From this point of view as well, water quality conservation in open water areas within the TGTM is required.

A conventional seawater exchange breakwater 1 that exchanges seawater outside the port into the inside of the port in order to maintain water quality inside the port has a breakwater main body 2 that divides the outside of the port 3 and the inside of the port 4 as shown in FIG. A flow path 5 is provided in the lower part of the breakwater main body 2 so as to communicate between the outside of the port 3 and the inside of the port 4 to facilitate seawater exchange using wave power or the like. In addition, the conventional seawater exchange breakwater 1 shown in FIG. 9 has a bellmouth-shaped portion 5A with a small loss on the outside port 3 side of the flow passage 5, and a protrusion portion 5D with a large loss on the inside port 4 side, and has It is designed to create a difference in the amount of inflow and outflow. In this way, the inflow into the port 4 is improved on average, and the flow of seawater in the port 4 is promoted. next,
The conventional seawater exchange breakwater 1 shown in FIG. 10 is provided with seven rattle valves 6 at the outlet of the flow path 5 on the port side 4. When the seawater flows in, the valve 6 opens due to wave force, allowing seawater to flow in, and when it flows out, the valve 6 opens. It closes to prevent seawater from flowing out.

In this way, one-way flow can always be expected toward the inside of the port 4, and the flow of seawater in the inside of the port 4 is promoted.

(Problems to be Solved by the Invention) However, in the structure shown in FIG. 8, when the wave height is small compared to the water depth, the waves outside the port 3 have a sinusoidal waveform,
For this reason, there is a problem that the flow rate becomes a reciprocating flow in the flow path 5, which is completely equal, and no inflow of water can be expected. In addition, in any of the types shown in FIGS. 8 to 10, pressure changes due to waves outside the port 3 propagate directly to the inside of the port 4 through the flow path 5, so new transmitted waves are generated inside the port 4. This is a fatal problem in terms of wave dissipation, which is the original purpose of breakwater 1.

An object of the present invention is to provide a seawater exchange breakwater that can maintain the water quality of a harbor area while keeping the interior of the pond calm.

(Means for Solving the Problems) The structure of the present invention for achieving the above second object will be explained with reference to FIGS. 1 to 7 corresponding to the embodiments. A breakwater main body 2 is provided so as to separate the inside of the port 4 from the inside of the port 4, and the upper part of the breakwater main body 2 is opened upward to collect overflow water 10 caused by overtopping waves 9 from the outside of the port 3. IOA, 10
Water storage tanks 11.11A and 11B are provided to store Lareta MA8! A water conduit 12° 12A that leads water to the bottom 7 side of the port 4 with a water head difference H of 10.1OA and 10Bt.
, 12B.

(Function) In this way, overflow water 1 caused by overtopping waves 9 from outside the port 3
0. IOA, 10B is the water storage 111 at the top of the breakwater main body 2
．． The water accumulates in 11A and 11B, and is drained to the bottom 7 side of the port 4 due to the water head difference H. Therefore, the inflow of seawater into the harbor 4 is made quiet because the water head difference H is used, and the water quality of the water area in the harbor 4 can be maintained while keeping the harbor 4 calm.

(Example) An example of the present invention will be described below with reference to FIGS. 1 and 2. In this embodiment, the breakwater main body 2 is provided on the bottom part 7 via the foundation aI 18 so as to partition the outside of the port 3 and the inside of the port 4. At the top of the breakwater main body 2, a water tank 11 is provided which opens upward and stores overflow water 10 caused by overtopping waves 9 from outside the port 3. The breakwater body 2 has a water tank 11
A water conduit 12 is provided in a single character shape for draining overflow water 10 accumulated in the port to the bottom 7 side of the port 4 by a water head difference H.

The cross section of the upper part of the breakwater main body 2 on the outside of the port 3 side is formed into an inclined surface 13 for the purpose of maximizing the inflow of sediment due to overtopping waves 9.

Such a seawater exchange breakwater 1 introduces overflow water 10 into the harbor interior 4 by using the water head difference H generated within the water storage layer 11, so wave pressure is not directly transmitted to the harbor interior 4, and the waves transmitted within the harbor are reduced to zero. can do. Moreover, according to such a structure, since the flow becomes completely unidirectional from the outside of the port 3 to the inside of the port 4, the flow of water within the port is promoted. Furthermore, the normal average incident wave height (
By setting an appropriate height of the overflow crest 14 for seawater (approximately 11 m or less), steady seawater ignition can be expected.

According to such a structure, the amount of dissolved oxygen in seawater increases due to disturbances such as frame wave phenomenon when overflow water 1o flows into storage water (n11). Therefore, as shown in Figure 13, overflow water with a large amount of dissolved oxygen When the flowing water 10A flows into the bottom 7 side l\ of the port interior 4, an aerobic condition is formed, and the self-purifying action of seawater becomes active due to aerobic decomposition of microorganisms within the bottom 7.

Furthermore, in the summer, generally, as shown in Figure 4, the surface water has a high temperature of 1 degree and becomes a high temperature zone 15, and the bottom water has a low temperature of 1 degree and becomes a low temperature zone 16, forming a so-called density stratification. Although seawater exchange in both directions is hardly carried out, in the structure of the present invention, the surface water in the high temperature section 15 is stored in the water storage tank 11 by overtopping waves, and this water is allowed to flow into the bottom water in the low temperature section 16 in the harbor interior 4. Therefore, the density stratification in the port interior 4 is destroyed,
The vertical pair 117 phenomenon promotes seawater exchange.

FIGS. 5 and 6 show other embodiments of the present invention. In this embodiment, a conduit 18 is connected to the headrace 12 of the breakwater main body 2 in the port 4, and the overflow water 10 accumulated in the water storage 11i11 is guided to the back of the port 4 by a water head difference and drained. It is.

In this way, it is possible to encourage the flow of seawater in the water area away from the breakwater main body 2 in the harbor 4 as shown in FIG.

FIG. 7 shows still another embodiment of the present invention.

In this embodiment, if the tidal difference in the target water area is large, waves may not exceed the overflow crest 14A at low tide. .

11B are provided on the top and bottom of the breakwater main body 2, and correspondingly, the headrace channels 12A and 12B are also provided respectively.

In this way, the effects of the present invention can be achieved even in waters with large tidal differences.

Note that the number of water tanks is not limited to two, and an appropriate number can be provided depending on the tidal difference.

(Effects of the Invention) As explained above, in the present invention, a water storage tank is provided in the upper part of the breakwater main body to store overflow water due to overtopping waves, and IfAR water collected in the water tank is transferred to the bottom side of the port via a headrace channel due to the water head difference. Since the overtopping water can be drained quietly into the port, it is possible to maintain the water quality of the water area within the port while keeping the port calm. In addition, overtopping water due to overtopping waves has a large dissolved oxygen layer due to disturbances such as frame wave conditions, and as this is drained to the bottom of the port, an aerobic state is formed in the bottom of the port, and microorganisms in the bottom sediment become aerobic. Decomposition can activate the self-purifying action of seawater.

Furthermore, according to the present invention, in the summer, overflow water from overtopping waves in the high temperature surface layer flows into the low temperature bottom layer inside the port through the water storage layer and the headrace channel, destroying the density stratification in the port and causing a rise in the vertical direction. Convection will occur and the exchange of seawater within the port can be promoted.

[Brief explanation of drawings]

1 and 2 are a cross-sectional view and a plan view of an embodiment of a breakwater according to the present invention, FIG. 3 is an explanatory diagram showing the state of supply of dissolved oxygen to the seabed by the breakwater of this embodiment, and FIG. The figure is an explanatory diagram showing the convection phenomenon of seawater in summer due to the breakwater of this embodiment, and Figures 5 and 6 are other examples of the present invention.
7 is a cross-sectional view and a plan view of the example, FIG. 7 is a plan view of the location of the embodiment of the present invention, and FIGS. 8 to 10 are conventional preventive measures. Jt Tsutsumi 3
FIG. 3 is a cross-sectional view showing an example of a stem. 1... Seawater exchange breakwater, 2... Breakwater main body, 3...
・Outside the port, 4...Inside the port, 7...Bottom, 9...Overtopping waves,
10.10A, 10B...overflow water, 11.11. fart,
11B... Water tank, 12.12A, 12B-... Headrace, 13... Inclined surface, 14.14A, 14B... Overflow top.

Claims (1)

[Claims] A breakwater body is installed to separate the outside of the port from the inside of the port.
A water tank is provided at the top of the breakwater main body and opens upward to store overflow water from overtopping waves from outside the port. A seawater exchange breakwater characterized by being provided with a headrace channel that flows into the bottom side.