JP2014037719A - Dam body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dam body capable of effectively and surely attenuating the energy of the tsunami, aftershock, and the like invading many times though it has a relatively simple and low-cost configuration and thus keeping damage due to the tsunami minimized.SOLUTION: An inventive dam body is a dam body 100 (dam body units 200) constructed with concrete in advance, transported to, and utilized in an installation site. A cross-sectional shape perpendicular to the axial direction of the dam body unit 200 is a triangular or polygonal shape. When a bottom surface (210) of the dam body unit 200 is installed on a seabed, the highest part (220) of the dam body unit 200 protrudes from a sea level by a prescribed amount, and when the power of water waves not less than a prescribed power is applied to the dam body unit 200, the dam body unit 200 turns in a plane perpendicular to the axial direction of the dam body unit 200.

Description

  The present invention relates to a structure of a dam body that can be used as a breakwater or a tide wall provided to prevent waves and tsunamis from the open ocean and to keep the inside of a harbor or coast (offshore part slightly away from the coast) calm and safe.

  Conventionally, in areas where high waves and tsunamis are likely to occur, in order to minimize damage from high waves and tsunamis, breakwaters and seawalls have been provided.

  In general, breakwaters are constructed at the entrance of the bay where they enter, reducing the tsunami wave height and current and delaying the arrival time of the tsunami to the shore, and reducing the tsunami wave height reaching the bay and going up to the land. Is designed to be minimal.

As an example of such a breakwater, it is described in Patent Document 1, for example, as shown in FIG. 9, a rubble mound 53 is constructed on the sea floor, and a caisson 55 having a wave-dissipating slit 54 formed thereon is installed. It is the composition which does.
Although not shown, the rubble mound 53 and the caisson 55 are fixed to the seabed using steel sheet piles, piles, or the like so as not to be easily broken or moved by the force of waves.

  In Patent Document 2, as an example of a levee body used as a tide embankment and a breakwater, a sheath pipe 15 is embedded in the seabed, a steel pipe 17 is inserted inside thereof, and the steel pipe 17 is attached to the sheath pipe according to the water level. 15 is moved up and down along the line 15.

Japanese Patent Laid-Open No. 7-113216 JP 2004-116131 A

  However, as described in Patent Document 1 and Patent Document 2, a conventional breakwater body such as a breakwater (such as a caisson 55 and a steel pipe 17) is erected fixedly on the seabed in a substantially horizontal direction. When a very large tsunami strikes, these dam bodies (caisson 55, steel pipe 17 etc.) are destroyed, and the height of the dam body with respect to the wave height disappears. There was a risk that the suppression effect against the tsunami that would strike without a loss would be lost.

  In addition, in order to construct a large breakwater that can cope with a large tsunami at a place to be constructed (installation place, site), a huge construction cost is required and the construction period may be prolonged. There is. Furthermore, there may be a possibility that construction for a long time cannot be performed at a place (installation place, site) where a breakwater should be constructed due to various requirements and conditions.

  The present invention has been made in view of the above-described circumstances, and can effectively and reliably attenuate the energy of a tsunami that repeatedly strikes, including aftershocks, etc., while having a relatively simple and low-cost configuration. Therefore, the purpose is to provide a levee body that can minimize damage caused by the tsunami.

The embankment according to the present invention is
A dike body that is pre-manufactured with concrete and transported to an installation location.
The cross-sectional shape perpendicular to the axial direction of the levee body is a polygonal shape of a triangle or more,
When the bottom surface of the levee body is installed on the sea bottom surface, the highest part of the levee body protrudes from the sea surface and a surface perpendicular to the axial direction of the levee body when a wave force exceeding a predetermined level is applied. The dam body is rotated inside.

  In the present invention, the levee body may be constituted by a dam body unit manufactured with a predetermined axial length.

  In the present invention, the bank body may be a hollow structure having a space inside.

  In the present invention, the space can be filled with a material having a small specific gravity (for example, water (seawater, fresh water), air, other liquids, gas, etc.) while being transported. Can be characterized by sinking a levee body by inserting a material with a large specific gravity.

  In the present invention, when a levee body installed at a predetermined installation location is moved, the levee body is lifted and moved again by discharging the large specific gravity put in the space, and returned to the original position and re-entered. It can be characterized as being installable.

  According to the present invention, while having a relatively simple and low-cost configuration, it is possible to effectively and reliably attenuate the energy of a tsunami that repeatedly strikes, including aftershocks, etc. It is possible to provide a dam body structure that can be kept to a minimum.

It is the perspective view which looked at the external appearance shape of the bank body (bank body unit) concerning one embodiment of the present invention from the slanting upper part. It is sectional drawing which shows the cross section in the plane orthogonal to the axial direction (long-axis direction) of the bank body (bank body unit) which concerns on embodiment same as the above. It is the side view which looked at the bank body (bank body unit) (type which has a hollow structure) which concerns on embodiment same as the above from the horizontal direction orthogonal to an axial direction (major axis direction). It is sectional drawing which shows the cross section (hollow structure) in the plane orthogonal to the axial direction (long-axis direction) of the bank body (bank body unit) which concerns on embodiment same as the above (it is an AA arrow line view of FIG. 3). . It is a figure explaining the mode in a dock (the dam body unit) which concerns on embodiment same as the above in a dock. It is a figure explaining a mode that the levee body (dyke body unit) which concerns on embodiment same as the above is towed from the inside of a dock, is conveyed to an installation place (installation place, the site), and is sunk. When the levee body (the dam body unit) according to the above embodiment has moved from the original position, the levee body (the dam body unit) is levitated, towed, transported to the original position, and then sinked. It is a figure explaining. It is a schematic diagram at the time of installing the bank body (bank body unit) concerning an embodiment same as the above in a harbor etc. It is a side view which shows an example of the conventional bank body.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the accompanying drawings. The present invention is not limited to the embodiments described below.

  FIG. 1 is a perspective view of a dam body 100 that can be used as a breakwater or a tide embankment according to an embodiment of the present invention.

  The levee body 100 according to the present embodiment is configured to include a concrete dam body unit 200, and one or a plurality of dam body units 200 are installed on an offshore part slightly away from the coast, or on the seabed of a harbor entrance part, Configured to mitigate the effects of tsunamis and high waves. The embankment 100 according to the present embodiment is installed as shown in FIG. 8, for example, and can be used as a breakwater or a tide embankment provided to prevent waves from the open ocean and keep the inside of the harbor calm.

  As shown in FIGS. 1 and 2, the bank body unit 200 constituting the bank body 100 according to the present embodiment has a substantially triangular cross-sectional shape in a plane orthogonal to the axial direction (long axis direction). ing. In addition, hereinafter, when simply referred to as a cross section, it refers to a cross section in a plane orthogonal to the axial direction (long axis direction).

  The dam body unit 200 according to the present embodiment is a concrete structure, and is installed and used so that the bottom (bottom surface) having a substantially triangular cross section is in contact with the sea bottom.

  For example, assuming that the tsunami wave height is 30 m and the tsunami wave height is 30 m, the dam body unit 200 according to the present embodiment is from the bottom side (each side can be the bottom) (bottom side) 210. It can be formed as a unit having a height to the apex portion 220 of about 50 m and a length in the major axis direction of about 100 m.

  In the present embodiment, the substantially triangular shape of the cross section of the dam body unit 200 is an edge-shaped triangular shape (a regular triangular shape having a side of about 70 m) with the apexes left at the tip so that destruction or the like is unlikely to occur. The chamfered shape or R shape can be obtained by shaving off (the length of each side after chamfering or R shape chamfering is about 50 m).

  Then, the concrete dam body unit 200 having a substantially triangular cross section is manufactured using, for example, a dock, and the completed dam body unit 200 is towed to a place where the dam body 100 is installed by a ship or the like. It is possible to adopt an installation method such as.

  When a tsunami or high wave reaches the levee body 100 (the dam body unit 200) installed at a desired location in the sea, a horizontal force acts on the dam body 100 (the dam body unit 200). The horizontal force is resisted by the frictional force generated on the bottom surface portion 210 and the protrusion 230 provided on the bottom surface portion 210. In addition, the cross-sectional shape of the protrusion 230 is not limited to the triangular cross-sectional shape, and may be other polygonal shapes, trapezoidal shapes, semicircular shapes, or the like. Further, the protrusion 230 is not limited to being formed continuously in the longitudinal direction, and for example, a plurality of three-dimensional shapes such as a cone, a pyramid, a cylinder, a truncated cone, and a hemisphere may be provided.

  When a greater force is applied in the horizontal direction, the levee body 100 (the dam body unit 200) is moved in the horizontal direction, or a protrusion projecting from the sea bottom to the dam body 100 (the dam body unit 200) side, The movement in the horizontal direction is restricted by the protrusion 230 provided on the bottom surface portion 210 of the body 100 (the dam body unit 200), so that the body 100 (the dam body unit 200) is rotated in the plane substantially orthogonal to the major axis direction (around the major axis) (Refer to the rotation direction in FIG. 2).

  However, since the dam body 100 (the dam body unit 200) according to the present embodiment has a substantially triangular cross section, the initial height (the height from the bottom surface portion 210 to the apex portion 220) can be obtained even when rotating around the major axis. Can always be maintained.

  Therefore, with a conventional levee that is fixed on the sea floor in a substantially horizontal direction, when a very large tsunami strikes, the dam body is destroyed and the height of the levee body in the wave height direction is Although there was a risk of loss, the levee body 100 (the dam body unit 200) according to the present embodiment can always maintain the initial height even if it is damaged by a tsunami. In addition, it is possible to maintain the suppression effect against the tsunami that repeatedly strikes.

  Moreover, the levee body 100 (the dam body unit 200) according to the present embodiment is manufactured as a unit in a dock or the like in a place different from the place (installation place, site) where the breakwater is to be constructed, Since this can be transported to the installation location for each unit, even for a large breakwater, the cost can be reduced, the manufacturing period can be shortened, and the breakwater should be constructed. The construction period at the (installation site, site) can also be shortened.

  Thus, according to the present embodiment, it is possible to effectively and reliably attenuate the energy of a tsunami that repeatedly strikes, including aftershocks, etc., while having a relatively simple and low-cost configuration. Therefore, it is possible to provide a bank structure that can minimize damage caused by the tsunami.

  By the way, the dam body unit 200 according to the present embodiment has a triangular cross section, a height of 50 m from the sea bottom to the highest part, a base of about 50 m in contact with the sea bottom, and a length in the major axis direction of about 100 m. However, the present invention is not limited to this.

  For example, the length in the long axis direction is preferably as long as possible in consideration of the influence of waves. However, a dock for manufacturing the dam body unit 200, a towing method to a place where the breakwater should be built (installation place, site), etc. Determine in consideration (for example, 100 m). The dock can be a dock for manufacturing and repairing a ship or the like.

  Adjacent levee body units 200 can be connected using a connecting device 300 as shown in FIG. 3 so as to perform substantially the same movement (horizontal movement, rotation around the long axis). For example, a bolt (for example, made of metal, resin, or ceramic) 310 threaded on the outer periphery and a fastening element (for example, made of metal, resin, or ceramic) 320 that is screwed with the bolt 310 are adjacent to each other. It can be set as the structure which attaches to the bank body unit 200, and fastens the volt | bolt 310 so that these may be connected. Or the code | symbol 310 can be set as a rod-shaped member, and the code | symbol 320 can be set as the accommodating element which accommodates this, and these can be connected by methods, such as welding and adhesion | attachment.

  In FIG. 3, the connecting device 300 is described as being configured inside the dam body unit 200, but is not limited thereto, and may be configured to be provided on the outer wall of the dam body unit 200. It is.

  Here, the dam body unit 200 according to the present embodiment may have a solid structure, but is not limited thereto, and may have a hollow structure.

  For example, as shown in FIGS. 3 and 4, buoyancy can be generated during transportation in the sea by making the hollow portion 240 air by using a hollow structure. This facilitates towing from a dock to a place (installation place, site) where a breakwater is to be constructed.

  In addition, in the dike unit 200 carried to the place (installation place, site) to be constructed, the inside of the hollow portion 240 is filled with gravel, etc., so that the specific gravity is increased, and the embankment unit 200 is submerged on the seabed (subsidence). It can be made the structure which can be made to install.

  As shown in FIGS. 3 and 4, the hollow portion 240 can be divided into a plurality of chambers 240 </ b> A, 240 </ b> B, 240 </ b> C by a partition wall 250 in order to maintain the strength and rigidity of the bank unit 200. .

  In this case, the chamber 240B can be filled through the opening 241b connected to the outside and through the opening 241g connected to the chamber 240A.

  The chamber 240C can be filled through the opening 241e connected to the outside and through the opening 241i connected to the chamber 240A.

  The chamber 240A can be filled through the openings 241a and 241f connected to the outside.

  In addition, it can also be set as the structure which uses a lid | cover (or stopper) element etc. about each opening part 241a-241f connected with the exterior, or a lid | cover (or stopper).

  The hollow portion 240 (the chambers 240A, 240B, and 240C) can be used not only for generating buoyancy but also as a right and left balancing ballast (a weight of seawater or gravel). It is also possible to perform towing by attaching a float or the like to the outer periphery of the bank unit 200.

  Here, an example of a state in which the dam body unit 200 manufactured at the dock is towed to a place (installation place, site) where a breakwater is to be constructed will be described with reference to FIG.

  As shown in FIG. 5A, the dam body unit 200 is completed at a dock.

  As shown in FIG. 5 (B), an appropriate amount of gravel or the like is poured into the hollow portion 240 (240B, 240C here) of the bank unit 200 as a ballast for balancing.

  Subsequently, as shown in FIG. 5C, the float bag 400 is attached to the outer periphery of the levee unit 200. In addition, when the buoyancy of the hollow portion 240 (the chambers 240A, 240B, and 240C) can be used, the attachment of the float bag 400 can be omitted.

  Then, as shown to FIG. 6 (A), seawater is guide | induced in a dock and the levee body unit 200 is levitated.

  In FIG. 6B, the levee body unit 200 is towed to a place (installation place, site) where a breakwater is to be constructed.

  Then, as shown in FIG. 6C, the floating bag 400 is removed, and the hollow portion 240 (the chambers 240A, 240B, 240C) is filled with gravel and the dam body unit 200 is laid down.

  As described above, the dam body 100 (the dam body unit 200) according to the present embodiment is manufactured as a unit in a dock or the like in a place different from the place (installation place, site) where the breakwater is to be constructed. However, since this can be transported to the installation location for each unit, even with a large breakwater, the cost can be reduced, the manufacturing period can be shortened, and a breakwater can be constructed. The construction period at the power location (installation location, site) can be shortened.

  Moreover, according to the levee unit 200 according to the present embodiment, even when the dam unit 200 is moved or rotated due to a tsunami or the like and moved away from the original position, the hollow portion 240 (the chamber 240A, 240B and 240C), gravel and the like are discharged, and buoyancy is generated using the float bag 400. By using such buoyancy, the hollow portion 240 (chamber is returned to the original position relatively easily. 240A, 240B, 240C) can be submerged by filling with gravel or the like, so that the embankment unit 200 can be re-installed in its original position with a comparatively short construction period and low cost (FIG. 7A). To FIG. 7 (C)).

  By the way, the material of the dam body unit 200 according to the present embodiment can be selected in consideration of being installed for a long period while being exposed to seawater.

  For example, as the concrete used in the dam body unit 200 according to the present embodiment, a long-life concrete that is assumed to have a life of about 100 times that of the current general concrete life of 100 years is adopted. be able to.

  Further, the reinforcing material embedded in the concrete and the connecting device 300 may be made of carbon fiber, resin, ceramic, or the like that is hardly affected by salt.

  The dam body unit 200 according to the present embodiment has been described as having a substantially triangular shape in cross section as shown in FIGS. 1 and 2, but is not limited to an equilateral triangle shape. And a substantially regular quadrangle or rectangle (the corners can be chamfered or rounded), a pentagon, or a polygon more than that.

  However, at the same height (height from the sea floor to the top), it is considered preferable to reduce the amount of concrete to be used and to have a substantially triangular shape with a large resistance to rotation.

  In the present embodiment, the dam body unit 200 is manufactured using a dock, and it is explained as being towed on the sea (or in the sea) and transported to the installation location. However, the present invention is not limited to this. Instead, for example, the present invention can also be applied to cases where land transportation, air transportation, and the like are included in the transportation route.

  The hollow portion 240, which is a space provided in the levee body, is installed with an object having a relatively low specific gravity, such as water (seawater, fresh water) or air, as having a low specific gravity during transportation. When installing in a place, the embankment can be submerged by putting in something with high specific gravity (sand, stone, etc.).

  The embodiment described above is merely an example for explaining the present invention, and various modifications can be made without departing from the gist of the present invention.

100 Dyke body 200 Dyke unit 210 Bottom side (bottom)
220 Apex part 230 Protrusion 240 Hollow part 240A-240C Chamber 241a-241f Opening part 250 Partition 300 Coupling device 310 Bolt (or rod-shaped member)
320 Fastening element (or containment element)
400 Floating bag

Claims (5)

A dike body that is pre-manufactured with concrete and transported to an installation location.
The cross-sectional shape perpendicular to the axial direction of the levee body is a polygonal shape of a triangle or more,
When the bottom surface of the levee body is installed on the sea bottom surface, the highest part of the levee body protrudes from the sea surface and a surface perpendicular to the axial direction of the levee body when a wave force exceeding a predetermined level is applied. An embankment characterized in that the embankment is rotated inside.   The levee body according to claim 1, wherein the dam body is configured by a dam body unit having an axial length of a predetermined length.   The levee body according to claim 1 or 2, wherein the dam body has a hollow structure having a space inside.   In the space, a thing with a small specific gravity is put into the space when transporting, and a dam body is sunk by putting a thing with a large specific gravity when installing in the installation place. The listed embankment.   When the levee body installed at a predetermined installation location moves, the levee body can be lifted and moved again by discharging the material with a large specific gravity put in the space, and returned to the original position and re-installed. The bank body according to claim 3 or claim 4.

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