JPH0819655B2 - Flexible mound - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a flexible mound (flexible submerged dike) for controlling the propagation of waves near the coast and the movement of sand such as the sea floor. The present invention relates to a flexible mound using a bag made of a material.

[Prior Art] Conventionally, as a submerged dike for controlling waves and sand near the coast, a method of stacking wave-dissipating blocks in the sea is generally used. However, this method has a problem in that a large amount of wave-dissipating blocks must be transported to the site, and the foundation work on the seabed at the construction site is troublesome, resulting in a long construction period and high costs. Also, if it is necessary to move or remove this after installation, the work will take a very long time and cost.

Furthermore, the submerged dike constructed by this wave-dissipating block breaks the wave on this crown and continues the turbulence by this breaking wave on a wide crown, thereby canceling the energy loss of the wave. It is a thing. Therefore, in order to obtain a sufficient wave-dissipating effect with such a submerged dike, it is necessary to raise the crown of the submerged dike to near the water surface and increase the width of the dike, which is extremely large. In addition to being unreasonable because of the large scale, there was also the inconvenience of hindering the navigation of vessels.

Therefore, the present applicant has, as an effective means for solving the above-mentioned problems, a bag body made of a sheet-shaped flexible material fixed and held on the seabed by an anchor or the like, and the bag body is injected into the bag body. We proposed a flexible mound (flexible submerged dike) consisting of a fluid such as seawater or air that inflates this bag (Japanese Patent Application No. 60-280790). This flexible mound facilitates work such as transportation, construction, movement or removal, and expects effective wave-dissipating effect even on a small scale by utilizing the flexibility of the flexible mound itself. it can. In other words, since it is possible to control waves with a small structure that is sufficiently submerged below the sea surface, it is becoming more and more rational that the sea area where the flexible mound is installed can be effectively used, and attention has begun.

Here, the principle of wave cancellation of this flexible mound will be described.

As shown in FIG. 3, it is assumed that a flexible mound 1 in which a fluid such as seawater is injected into a bag made of a flexible material is installed on the seabed G. At this time, the incident wave W is transmitted along the sea surface S toward the flexible mound 1.
Energy of the incident wave W is transmitted to the flexible mound 1 and the flexible mound 1 is deformed as shown by the dotted line in FIG. Then, as the flexible mound 1 is deformed, a radiation wave R is emitted from the flexible mound 1 itself toward the sea surface S as indicated by an arrow A in the figure, and the radiation wave R and the incident wave W interfere with each other. Is performed. At the same time, since a part of the energy of the incident wave W is consumed along with the flexible mound 1, the waves (transmitted wave and reflected wave) after incident are extinguished.

[Problems to be Solved by the Invention] However, in such a flexible mound, a part of the energy of the incident wave is consumed along with the deformation of the flexible mound, but the amount of energy loss is not so large, so It is difficult to significantly reduce the wave height of the latter wave, that is, both the transmitted wave and the reflected wave. That is, if the wave height of the transmitted wave is lowered, the wave height of the reflected wave becomes relatively large. Therefore, in order to sufficiently reduce both the wave heights of the transmitted wave and the reflected wave, it is necessary to add a function of losing the wave energy of the incident wave to the flexible mound.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and provide a flexible mound having a large wave-dissipating effect for both transmitted waves and reflected waves.

[Means for Solving the Problems] In the present invention, in a flexible mound including a bag body made of a flexible material and a fluid filled in the bag body, a space between the bag body and its fixing ground. The solution is to provide a damping device.

[Operation] By providing the attenuator between the flexible bag and the fixing portion as described above, the wave caused by the interference between the incident wave and the radiated wave and the deformation of the bag itself as in the conventional case. In addition to the energy loss of the wave, the energy of the wave is absorbed and attenuated by the attenuator through the bag, and the wave extinguishing effect appears.

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

FIG. 1 shows an example of the flexible mound of the present invention. In the figure, reference numeral 1 is a flexible mound, and the flexible mound 1 is made of a flexible material and has a bag body 2 which forms an outer shell of the flexible mound.
The bag 2 is generally composed of a fluid 3 such as seawater or water which is injected into the bag 2 to inflate it.

The bag 2 is an upper sheet 2a made of a flexible material such as a rubber sheet or a vinyl chloride sheet.
The bottom sheet 2b and the bottom sheet 2b are liquid-tightly and integrally joined at their edge portions, and the bag body 2 is filled with a fluid 3 such as seawater or water. 2, the bottom sheet 2b can maintain a flat shape and the upper sheet 2a can maintain a convex shape curved upward.

Also, in the flexible mound 1 of this example,
A plurality of damping devices 4 are provided between the outer surface of the bottom sheet 2b of the bag body 2 and the seabed ground (fixed ground) G. The damping device 4 is made of laminated lead rubber obtained by laminating lead rubber, and is installed on each base portion 5 formed on the surface layer of the seabed ground G. The number of such attenuators 4 is not particularly limited, but it is necessary to design so that when a wave arrives, at least the deformation of the bag 2 that can not lose the energy of the wave can be absorbed. , The size of the flexible mound 1, the expectation of the wave-dissipating effect, and other factors. Further, the damping device 4 can easily change the damping ratio by changing the number of laminated lead rubbers, and the degree of freedom in designing the wave-absorbing structure can be increased. Furthermore, since the laminated lead rubber has excellent corrosion resistance and durability, the damping effect of the damping device 4 can be maintained for a long period of time, maintenance-free, and easy replacement.

As described above, in the flexible mound 1 of the present invention, when a wave arrives at the flexible mound 1, the energy of the wave is transmitted to the bag body 2 to deform the bag body 2. At the same time, the bag body 2 Is absorbed by the attenuator 4 installed between the bag body 2 and the seabed G, and the energy of the waves is synergistically attenuated as a result, and a wave-dissipating effect appears. Therefore, in the flexible mound 1 of this example,
Compared with a flexible mound that does not have a damping device, the degree of attenuation of wave energy is large, and a sufficiently high wave-dissipating effect can be obtained.

FIG. 2 shows another embodiment of the flexible mound according to the present invention, and the same members as those in the above embodiment are designated by the same reference numerals.

The flexible mound 1 of this embodiment includes a damping pot 7a having a damping rate h and a spring 7b having a spring constant k in the middle of an anchor net 6 for fixing the bag body 2 to the seabed G. A plurality of devices 7 are attached.

Also with such a damping device 7, ... When a wave arrives, the energy of the wave is transmitted to the bag body 2 to deform the bag body 2 and, at the same time, the damping device 7 via the bag body 2 and the anchor net 6. The energy of the waves is synergistically attenuated as a result, and a high wave-dissipating effect can be obtained.

[Effects of the Invention] As described above, the flexible mound of the present invention includes a bag body made of a flexible material and a fluid filled in the bag body, and between the bag body and the fixing ground thereof. Since the attenuator is provided, the energy of the wave is absorbed by the attenuator, in addition to the conventional flexible mound, which is the wave cancellation caused by the interference between the incident wave and the radiated wave and the deformation of the flexible mound itself. And decay. Therefore, a high wave-dissipating effect can be obtained by these synergistic effects.

[Brief description of drawings]

FIG. 1 and FIG. 2 are sectional views showing different examples of the flexible mound of the present invention, and FIG. 1 ... Flexible mound, 2 ... Bag, 3 ... Fluid, 4, 7 ... Damping device, G ... Submarine ground (fixed ground).

Front page continuation (72) Inventor Yasuo Kajioka 2-16-1, Kyobashi, Chuo-ku, Tokyo Shimizu Construction Co., Ltd. (72) Masahiro Tanaka 2--16-1, Kyobashi, Chuo-ku, Tokyo Shimizu Construction Stock Inside the company (72) Takumi Oyama 2-16-1 Kyobashi, Chuo-ku, Tokyo Shimizu Construction Co., Ltd. (72) Inventor Tadashi Ono 2-16-1 Kyobashi, Chuo-ku, Tokyo Shimizu Construction Co., Ltd. (72) Inventor Hiroki Ouchida 2-16-1, Kyobashi, Chuo-ku, Tokyo Shimizu Construction Co., Ltd. (72) Inventor Hisao Abe 2-16-1, Kyobashi, Chuo-ku, Tokyo Shimizu Construction Co., Ltd. ( 72) Inventor Satoshi Kiyokawa 2-16-1, Kyobashi, Chuo-ku, Tokyo Shimizu Construction Co., Ltd. Asahi 1 Asahi, Tsukuba City, Ibaraki Prefectural Government, Civil Engineering Research Institute, Ministry of Construction (56) Reference JP-A-64-83704

Claims (1)

[Claims] 1. A bag body made of a flexible material and a fluid filled in the bag body, and a damping device is provided between the bag body and its fixing ground. Flexible mound.