JP6067360B2 - Tsunami attenuation device - Google Patents

Description

  The present invention relates to a tsunami attenuation device installed on the sea floor.

  Conventionally, breakwaters are constructed on the coast to prevent tsunamis, but conventional reinforced concrete tsunami breakwaters are designed to withstand the impact of tsunamis by making the breakwaters large, heavy and solid. Therefore, it has to be constructed using a large amount of materials, and it takes a long period of time for construction, and there is a problem that a large construction cost is required.

  On the other hand, as a tsunami breakwater to be installed on the sea floor, the impermeable curtain body is suspended from the floating body that floats on the sea surface, and the lower edge of the curtain body is fixed to the sea floor. A tsunami breakwater has been proposed that connects a plurality of mooring lines (for example, see Patent Document 1).

  However, this tsunami breakwater has a high resistance to water because the membrane provided between the floating body that floats on the sea surface and the fixed point of the sea floor is impermeable. It becomes a shape that is crushed as if the character was tilted sideways, and it is difficult to deploy it in water.

JP 2006-249914 A

  The present invention has been made to solve the above-mentioned problems, and the purpose of the present invention is to dampen a tsunami generated by a submarine earthquake or the like with a net-like object deployed in water, and easily on the seabed. And it is providing the tsunami attenuation device which can be installed efficiently.

In order to achieve the above object, a tsunami damping device according to the present invention has a lower end of a net-like object fixed to first mooring means, and the upper end of the net-like object and second mooring means are connected by a plurality of mooring lines. The net-like object is integrated with the first and second mooring means and the mooring line, and at least one stage of a water-impermeable sheet is spread on the net-like object. A floating body is attached to a portion of the net-like object corresponding to the upper end of the sheet, and the length of the first mooring means is made equal to the lateral width of the net-like object, and the length of the second mooring means is It is characterized by being equal to the length of the first mooring means or slightly shorter than the length of the first mooring means .

  The present invention fixes the lower end of the net-like object to the first mooring means, connects the upper end of the net-like object and the second mooring means by a plurality of mooring lines, and Since the second mooring means and the mooring line are integrated, the tsunami attenuation device can be easily and efficiently installed on the seabed using a work ship having a crane. In addition, at least one level of the water-impermeable sheet is spread on the net-like material, and a floating body is attached to a portion of the net-like material corresponding to the upper end of the water-impermeable sheet. The material is lifted and lift is generated in the first water-impermeable sheet.

It is a top view containing the partial cross section of the tsunami attenuation apparatus which concerns on this invention. It is a side view of a mooring means. It is a principal part expanded side view of a mooring means. It is installation work explanatory drawing of a 1st mooring means. It is installation work explanatory drawing of a 2nd mooring means. It is underwater expansion explanatory drawing of the tsunami attenuation apparatus which concerns on this invention. It is the front view which connected the adjacent tsunami attenuation device and unitized.

  Embodiments of the present invention will be described below with reference to the drawings.

  As shown in the plan view of FIG. 1, the tsunami attenuation device 1 according to the present invention fixes the lower end of the net-like member 2 to the first mooring means 3, and the upper end of the net-like member 2 and the second mooring means 4. Are connected by a plurality of mooring lines 5, and the net-like member 2, the first and second mooring means 3, 4 and the mooring lines 5 are integrated.

  In this embodiment, two impermeable sheets 6a and 6b are spread on the front surface of the net-like member 2 so as to be in two upper and lower stages in FIG. 1, but the impermeable sheet is installed. The number of stages may be one or three or more.

  At that time, the first water-impermeable sheet 6 a is spread on the net-like member 2 so that the upper end thereof coincides with the upper end of the net-like member 2. Further, a gap 8 is provided between the first-stage impermeable sheet 6a and the second-stage impermeable sheet 6b as shown in FIG. As a result, the flow around the first impermeable sheet 6a becomes equivalent to the flow around the blade cross section, and lift is generated in the sheet 6a. Further, the floating body 7 is attached to the upper end of the net-like member 2 and the floating body 7 is also attached to the portion of the net-like member 2 corresponding to the upper end of the second water-impermeable sheet 6b.

  Examples of the impervious sheets 6a and 6b include a sheet in which a canvas is impregnated with a thermoplastic synthetic resin, or a sheet in which synthetic resin sheets are bonded to both sides of a cloth. In short, it is preferable to have water permeability, toughness, high durability and flexibility.

  In addition, buoys 11 serving as marks are attached to the left and right ends of the upper end of the net-like member 2 via ropes 10 so that the installation location of the tsunami attenuation device 1 installed on the seabed 20 can be understood.

  At this time, the length of the first mooring means 3 is made equal to the width of the net-like member 2, and the length of the second mooring means 4 is made equal to the length of the first mooring means 3 or the first mooring means 3. (See FIG. 1).

  Further, as shown in FIG. 2, a large number of rod-like anchor claws 9 are provided at the bottoms of the first mooring means 3 and the second mooring means 4. In addition, as shown in FIG. 3, it is preferable to incline the anchor nail | claw 9 provided in the bottom part of the 1st mooring means 3 and the 2nd mooring means 4 toward the land.

  The tsunami attenuation device 1 preferably has a weight close to a specific gravity 1 by the net-like member 2, the two impermeable sheets 6 a and 6 b, and the floating body 7. By setting in this way, as shown in FIG. 6, the upper end of the net-like member 2 rises from the seabed 20 even during a normal time, making it easier to catch the first tsunami wave.

  Next, the installation method of the tsunami attenuation apparatus 1 is demonstrated. In addition, the code | symbol W has shown the sea surface.

  After transporting the tsunami attenuation device 1 to the water area to be installed by the work boat 13, the wire 15 connected to the first mooring means 3 of the tsunami attenuation device 1 is suspended by the crane 14 of the work boat 13 as shown in FIG. 4. However, the first mooring means 3 of the tsunami attenuation device 1 is installed on the bottom 20. At that time, the net-like member 2 is dragged by the first mooring means 3 and drawn into the water. When the first mooring means 3 reaches the bottom 20, the wire 15 is removed from the first mooring means 3.

  Thereafter, as shown in FIG. 5, the work ship 13 is moved from the installation location of the first mooring means 3 by a predetermined distance toward the offshore, and then the wire 15 connected to the second mooring means 4 of the tsunami attenuation device 1. The second mooring means 4 of the tsunami attenuation device 1 is installed on the bottom 20 while being suspended by the crane 14 of the work boat 13. When the second mooring means 4 reaches the bottom 20, the wire 15 is removed from the second mooring means 4.

  As shown in FIG. 6, the tsunami attenuation device 1 installed on the seabed 20 floats in the water without causing the upper end of the net-like member 2 to contact the seabed 20 as shown by a broken line during normal times. It is easy to catch.

  When a submarine earthquake occurs and the first tsunami wave strikes, the net-like member 2 is lifted by the first tsunami wave as indicated by the alternate long and short dash line, and is spread on the upper end of the net-like member 2. 6a becomes a shape like the main wing of an aircraft.

  Thus, lift is generated in the impervious sheet 6a by the fast flow along the upper surface of the impervious sheet 6a shaped like the main wing of an aircraft, and the net-like member 2 is indicated by a two-dot chain line. Stand up as shown.

  The tsunami blocked by the net-like member 2 that stands up as indicated by the two-dot chain line is pushed back toward the offing, and the power of the tsunami that continues to push down is reduced.

  As shown in FIG. 7, the upper ends of the net-like members 2 and 2 of two adjacent tsunami attenuation devices 1 and 1 can be connected by a shackle 17 or the like to be unitized.

2 Net-like object 3 First mooring means 4 Second mooring means 5 Mooring line 6a First-stage impermeable sheet 6b Second-stage impermeable sheet 7 Floating body

Claims (1)

The lower end of the net-like object is fixed to the first mooring means, the upper end of the net-like object and the second mooring means are connected by a plurality of mooring lines, and the net-like object and the first and second mooring means. And the mooring line is integrated, and at least one impermeable sheet is spread on the net-like material, and a floating body is attached to the net-like portion corresponding to the upper end of the impermeable sheet. And
The length of the first mooring means is made equal to the width of the net-like object, and the length of the second mooring means is made equal to the length of the first mooring means or slightly longer than the length of the first mooring means. Tsunami attenuation device characterized by shortening .

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