JP2014058812A - Floating-type sand beach rearing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a floating-type sand beach rearing system which can be constructed relatively easily and at a low cost, reliably and effectively presents wave-absorbing action to effectively prevent occurrence of damage caused by tsunami or tidal waves, and can be simultaneously contributed to rearing of a sand beach.SOLUTION: The floating-type sand beach rearing system is configured by horizontally disposing a plurality of wave-absorbing bodies 1 side by side at appropriate intervals. The wave-absorbing body 1 is formed from a floating body 2 and a stand 5. The floating body 2 includes an offshore-side end portion 3 which is turned toward an offshore side, and a land-side end portion 4 which has greater buoyancy than the offshore-side end portion 3 and is turned to a land side. The floating body 2 is oscillated while following vertical movement of waves by pivoting the offshore-side end portion 3. The stand 5 is erected relatively shallow in the water of the coast and pivots the offshore-side end portion 3. The floating bodies 2 are adjusted in height so as to be horizontal in the case of ebb tide at the neap and are installed so as to be inclined horizontally with respect to a forward movement direction of waves.

Description

  The present invention is a floating sandy beach growing device, more specifically, installed in the water of the sea or river to demonstrate the wave-dissipating function, thereby preventing damage caused by tsunamis and high waves and contributing to the growth of sandy beaches. The present invention relates to a floating sand beach breeding device that can be used.

  In order to prevent damage caused by tsunamis, high waves, etc., various wave-dissipating devices installed in relatively shallow coastal areas have been considered. A plurality of U-shaped dam bodies exposed from the water surface are arranged in parallel in the same direction, and a U-shaped water channel is provided between each dam body (JP-A-6-212611), or all It is formed in an arc shape (substantially hemispherical) with respect to the direction of the azimuth wave, and a hollow chamber is provided inside, and this hollow chamber is connected to the sea through an opening provided in a portion facing the main wave direction. An example is a communication system (Japanese Patent Laid-Open No. 10-237842).

  These conventional wave-dissipating devices are not only expensive per se due to their structure, but also have the disadvantage that they are troublesome to install and increase the total cost. In order to eliminate this drawback, the present inventor has previously disclosed a wave-dissipating method and apparatus having a simple structure, the cost of the apparatus itself and the installation cost being relatively low, and having an effective wave-dissipating effect. (Patent No. 3609052).

  The wave-dissipating device according to the invention has one or a plurality of C-shaped wave-dissipating bodies having an opening side surface extending in the length direction, and the opening side surface is directed in the wave traveling direction and inclined with respect to the wave traveling direction. The water flow is generated between the offshore end and the land end of the wave-dissipating body when the wave hits the offshore end of the wave-dissipating body. This is characterized in that a flow can be generated in the wave-dissipating body due to the pressure difference.

  However, even in the case of this wave-dissipating device, the cost of the wave-dissipating body itself including the fixed pile and the cost for the installation work increase, and therefore, the appearance of a wave-dissipating device with further reduced costs has been desired. Further, a large gap is formed between the wave-dissipating bodies at the time of installation, and a wave can escape from the gap, and the wave that has passed may make the wave-dissipating action insufficient.

JP-A-6-212611 JP-A-10-237842 Japanese Patent No. 3609052

  The present invention has been made in view of the problems in the conventional wave-dissipating device described above, and there is no problem that a part of the waves escapes through the gap between the wave-dissipating bodies to obstruct the wave-dissipating action, and is relatively easy It is an object of the present invention to provide a floating sand beach growing apparatus that can be constructed at low cost, has a wave-dissipating effect reliably and effectively, and consequently grows a sand beach.

  The invention according to claim 1 for solving the above-mentioned problems includes an offshore side end portion directed to the offshore side, and a land side end portion having a larger buoyancy than the offshore side end portion and directed to the land side. A floating body that swings following the up and down movement of the wave by pivoting the offshore end, and the offshore end standing in a relatively shallow water of a coastal area. A plurality of wave-dissipating bodies comprising a stand that pivotally supports the section are arranged in parallel at appropriate intervals, the height of the floating body is adjusted so that it is in a horizontal state at low tide and the wave travels It is a floating sandy beach growing apparatus characterized by being installed so as to be inclined in a horizontal direction with respect to a direction.

  In one embodiment, the floating body is a bundle of a large number of bamboo or bamboo shoots, the root side being bound and pivotally supported by the offshore end, and the leaf side being unbound in the land. It is a side end. In another embodiment, the floating body is a hollow resin cylinder in which the land-side end portion is larger than the offshore-side end portion.

  In one embodiment, a cradle is included that is buried under the land-side end of the floating body to receive the land-side portion of the floating body and prevent its submarine burial. The stand may be provided with a stopper that regulates the rising angle of the floating body.

  As described above, the floating sand beach breeding apparatus according to the present invention has an offshore side end and a land side end having a larger buoyancy than the offshore side, and the offshore end is pivotally supported. Accordingly, a plurality of wave-dissipating bodies each composed of a floating body that oscillates in response to waves and a stand that pivotally supports the offshore end are arranged in parallel at appropriate intervals, and the floating body is a low tide at low tide. Sometimes the height is adjusted so that it is in a horizontal state, and it is installed so as to incline in the horizontal direction with respect to the traveling direction of the wave. With a simple configuration, it is constructed relatively easily and at low cost. As the floating body of each wave-dissipating body swings in response to the wave, a wave-dissipating effect is obtained. There is an effect.

  In particular, in the invention described in claim 2, there is an effect that the material cost can be considerably reduced. In the invention described in claim 4, the excessive swinging of the floating body downward is suppressed and the floating is suppressed. Adhesion of seaweeds and the like is prevented as much as possible, and the floating body is maintained in buoyancy. In the invention according to claim 5, the inversion of the floating body is suppressed and damage to the wave-dissipating body is prevented. is there.

It is a perspective view which shows the wave-dissipating body in one Embodiment of the floating-type sand beach growing apparatus which concerns on this invention. It is a perspective view which shows the installation state of one Embodiment of the floating type sand beach cultivation apparatus which concerns on this invention. It is a perspective view which shows the rocking | fluctuation state of the floating sand beach growing apparatus in one Embodiment of the floating sand beach growing apparatus which concerns on this invention. It is a perspective view which shows the wave-dissipating body in other embodiment of the floating type sand beach cultivation apparatus which concerns on this invention. It is a figure for demonstrating the effect | action in one Embodiment of the floating type sand beach cultivation apparatus which concerns on this invention.

  Embodiments of the present invention will be described with reference to the accompanying drawings. As shown in FIG. 1 to FIG. 3, the floating sand beach breeding apparatus according to the present invention includes an offshore side end portion 3 directed toward the offshore side during installation and a landside end portion 4 directed toward the land side during installation. A floating body 2 that swings in response to a wave and a stand 5 that is erected in a relatively shallow water, for example, 100 to 200 m offshore and pivotally supports the offshore end 3. A plurality of wave bodies 1 are arranged side by side. A plurality of the floating sand beach growing devices are arranged at appropriate intervals so that the wave-dissipating body 1 is inclined in the horizontal direction with respect to the wave traveling direction.

  The floating body 2 is configured to have sufficient buoyancy on the land side. The floating body 2 in the embodiment shown in FIGS. 1 to 3 is formed by bundling a large number (for example, 30 to 40) of bamboo or cocoons having a length of 4 to 5 meters. In that case, the root side is the offshore side end 3 that is directed to the offshore side during installation, and the leaf side is the landside end 4 that is directed to the landside at the time of installation. For example, the 3 and 4 locations of the offshore side end 3 are strong. The land-side end 4 is bound and spread in an appropriate manner without being bound. Each floating body 2 has its offshore side end 3 pivoted by a stand 5 and swings in accordance with the vertical movement of the wave, and is in an upright state depending on the water level (see FIG. 3).

  The stand 5 is formed, for example, by assembling metal pipes, and is constructed by vertically and horizontally assembling metal pipes for fixing a pair of support columns 6 and 7 standing in water and the offshore side end 3 of the floating body 2. The fixed frame 8 is configured, and the universal joint 9 is provided between the fixed frame 8 and the support columns 6 and 7 and pivotally supports the fixed frame 8 so as to be swingable. In that case, the offshore side end 3 of the floating body 2 is fixed to the fixed frame 8 by means such as placing on the fixed frame 8 and tying it. In addition, the length of the part to which the fixed frame 8 in the offshore side edge part 3 is fixed shall be about 1/4 of the full length.

  The height of the pivot support position of the floating body 2 in the stand 5 is set so that each floating body 2 is in a horizontal state at low tide. This height corresponds to the height of drifting sand from the offshore and the height of the sea surface when passing through the offshore current. It is prevented that the sea sand landscape is exposed on the water surface and the seascape is damaged.

  In a preferred embodiment, the stand 5 is provided with a stopper (not shown) that restricts the rising angle of the floating body 2 to prevent inversion. This stopper can be constituted by, for example, a pipe passed between the support columns 6 and 7 above the fixed frame 8. Needless to say, the pipe in that case is passed between the land sides of the columns 6 and 7. Further, the stopper may be a pin protruding from the support columns 6 and 7 to the upper side of the fixed frame 8.

  In a preferred embodiment, a cradle 10 that receives the land-side portion of the floating body 2 and prevents the seabed from being buried under the land-side end 4 of the floating body 2 is installed. The cradle 10 may be provided for each floating body 2 or may be of a length that can receive the plurality of floating bodies 2 across the plurality of floating bodies 2. The height of the cradle 10 is substantially the same as the pivot position height of the offshore side end 3 of the floating body 2 and holds the floating body 2 at a level higher than the water level at the time of low tide.

  In the case of this embodiment, since the floating body 2 is received by the cradle 10, a space that always allows passage of the rip current is secured between the floating body 2 and the seabed, so that the drifting sand moves to the land side. On the other hand, the rip current flows offshore without being blocked by the floating body 2. This point will be further explained.Waves that arrived in shallow water through the bottom of the sea bottom return to the offshore side as rip currents, but the waves on the land side of each floating sand beach breeding device have a momentum as described later. Because it is killed, when it returns as a rip current, it gently passes through the space secured under each wave-dissipating body 1. However, if such a space is not secured, the rip current will be blocked there and a swirl will occur in the vicinity, and the sand on the sea floor will be eroded, making it difficult to grow the sandy beach .

  Furthermore, since the floating body 2 is received by the cradle 10 and is prevented from being buried in the seabed, seaweeds, shellfish, wrecked objects, etc. are entangled with the seabed buried, and the weight cannot be lifted and the wave-dissipating effect is obtained. It is reliably prevented from fading. In addition, since the cradle 10 is installed at a height that holds the floating body 2 above the water level at the time of low tide, the land side end 4 of the floating body 2 is exposed to the sea surface at the time of low tide. become. Thus, the seaweed and shells entangled with the land side end 4 (not so much as when buried in the seabed, but some floating seaweed etc. are entangled), and since it is dried and blown away by the wind, the buoyancy of the floating body 2 is secured. Is done.

  In the embodiment shown in FIG. 4, the floating body 2 is configured with a resin hollow body in which the land-side end 4 is larger than the offshore-side end 3. The floating body 2 in this case becomes swingable when the shaft inserted through the offshore side end portion 3 is pivotally supported by a universal joint 9 installed on the support columns 6 and 7.

  The floating sandy beach cultivation apparatus according to the present invention has a number of wave-dissipating bodies 1 composed of the floating body 2 and the stand 5 configured as described above, and is spaced apart so that the land-side ends 4 of the floating bodies 2 spread lightly. Or a plurality of such floating sandy beach growing devices, each of which has a horizontal direction of, for example, about 20 to 45 degrees with respect to the wave traveling direction. Inclined and arranged at appropriate intervals (see FIG. 5). The installation position is preferably a place where white waves appear at the boundary between the deep field and the shallow field in water 100 to 200 m offshore in the coastal region. The wave traveling direction is determined by the seabed topography of the coast.

  At the time of installation, the height of the pivotal support position of each floating body 2, in other words, the height of the universal joint 9 installed on the support columns 6, 7 is set in accordance with the sea level at the time of low tide at the installation location. Is done. The adjustment of the height of the universal joint 9 can be performed by configuring the universal joint 9 so as to be slidable in the vertical direction with respect to the columns 6 and 7, or the embedment depth of the columns 6 and 7 is changed. Can also be done.

  By installing the floating sand beach growing apparatus according to the present invention as described above, the sand beach growing effect can be obtained simultaneously with the wave-dissipating effect. That is, the incident wave w1 arriving toward each floating sand beach growing device hits the floating sand beach growing device, and part of the incident wave w1 is dispersed and quenched by passing through the device, and part of the incident wave w1 is refracted by about 90 degrees. The reflected wave w2 is obtained (see FIG. 5).

  However, since each floating sand beach growing device is installed so as to be inclined in the horizontal direction, for example, about 20 to 45 degrees with respect to the traveling direction of the waves, the incident wave w1 is one floating sand beach. Rather than hitting the growth device at the same time over the entire width, the time to hit the wave-dissipating body 1 located on the most offshore side (the earliest) and the time to hit the wave-dissipating body 1 located on the most land side ( There is a time difference. That is, the refracting portion that becomes the reflected wave w2 from the incident wave w1 moves along the device inclined with respect to the traveling direction of the wave, and is subjected to a wave-dissipating action in the process.

  As described above, the incident wave w1 hits each floating sandy beach growing device, and a part of the incident wave w1 passes through the gap between the wave-dissipating bodies 1 having a low water flow pressure to the land side. . As the incident wave w1 is dispersed and extinguished, on the land side of the floating sandy beach breeding device, there is a stagnation area of the drifting sand accompanying the wave breaking, and the drifting sand accumulates there. Will be nurtured. Since each floating body 2 rises following the water level as it rises, the wave-dissipating action is not lost by the water level.

  In addition, the seawater which hits the inclined surface from the deep field of the seabed to the shallow field becomes a rising wave that rises obliquely upward along the inclined surface. When this rising wave hits the floating body 2 on which the offshore end 4 is pivoted from below, the floating body 2 swings upward in response to the rising wave and disappears as resistance. Acts like a wave. Further, even when this rising wave rises on the offshore side of the apparatus and breaks down on the floating body 2, the wave force is attenuated by the resistance of the floating body 2. In addition, the incident wave w1 which goes to the land side also fades by receiving the influence of this rising wave.

  The present inventor manufactured a floating sandy beach growing apparatus of floating body 2 bundled with bamboo and installed it as described above. When the sandy beach was observed 4 days after passing through the low pressure, as shown in FIG. It was confirmed that small sand piles 11 were formed in two places on the sandy beach, offshore and on land. This is because the low tide and the high tide are twice a day, but the result of the accumulation of sand drift in two rows due to the difference in tide level between the high tide at night and the high tide at noon. The lowland is the trace of the offshore flow. And it was also able to confirm that the sand which forms this sandy mountain 11 was blown off to the land side on the sea breeze after drying, and as a result, a flat sandy beach was nurtured.

  Although the invention has been described in some detail with its most preferred embodiments, it is evident that a wide variety of embodiments can be constructed without departing from the spirit and scope of the invention. For example, in addition to the above-described configuration, the floating body may have a configuration in which a branch-like protrusion or a large number of cross members are provided at the end of the bar. Accordingly, the invention is not limited to that particular embodiment, except as limited in the appended claims.

DESCRIPTION OF SYMBOLS 1 Wave-dissipating body 2 Floating body 3 Land side edge part 4 Offshore side edge part 5 Stand 6, 7 Post 8 Fixed frame 9 Shaft support member 10 Base 11 Sand mountain

Claims (5)

  It has an offshore end that is directed to the offshore side and a land end that has a greater buoyancy than the offshore end and is directed to the land, and the offshore end is pivotally supported. A plurality of wave-dissipating bodies, each of which is composed of a floating body that swings following the vertical movement of the wave and a stand that is erected in the relatively shallow water of the coast and pivotally supports the offshore end. It is configured to be arranged side by side at intervals, the height of the floating body is adjusted so as to be in a horizontal state at the time of low tide, and the floating body is installed so as to be inclined in the horizontal direction with respect to the wave traveling direction. Floating sand beach growing device.   The floating body is a bundle of a large number of bamboo or bamboo shoots, the root side being bound and pivotally supported, and the leaf side being released to become the land side edge. Floating sand beach cultivation device as described in 1.   2. The floating sand beach growing apparatus according to claim 1, wherein the floating body is a hollow resin cylindrical body in which the land-side end portion is larger than the offshore-side end portion.   The cradle is installed under the land side end of the floating body, and includes a cradle that receives the land side portion of the floating body and prevents its submarine burial. Floating sand beach growing device.   The floating sand beach growing apparatus according to any one of claims 1 to 4, wherein the stand is provided with a stopper that regulates a rising angle of the floating body.

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