JP6674220B2 - Landing method by coral gravel accumulation, permeation structure and structure therefor - Google Patents

Description

  The present invention relates to a method of depositing and landing coral gravel, a permeable structure and a structure therefor.

  Japan's territorial waters and the Exclusive Economic Zone (EEZ) are the bases of about 500 remote islands, but the conservation and management of remote islands is needed to protect underwater resources and marine resources. The need for conservation and utilization of coral reefs has been recognized, as coral reefs surround the islands on remote islands. For example, Patent Literatures 1 and 2 relocate coral reefs, Patent Literatures 3 and 4 proliferate coral reefs, Patent Literature 5 cultivates and protects corals, Patent Literature 6 prevents scattering of coral rubble fragments, and Patent Literature 7 discloses coral reefs We propose technologies such as construction of breeding structures.

JP 2011-125293 A JP 2006-158218 A JP 2008-141979 JP 2011-125347 A JP 2014-212704 A JP 2014-212702 A JP 2013-165693 JP

  In the vicinity of remote islands where coral reefs are dominant, dead corals have become sand and gravel, and there are places where coral gravel has formed islands and landed due to weather and sea conditions. At locations where coastal erosion is predominant, breakwaters made of stone and blocks may be constructed for the purpose of coastal conservation, but the sandy beach behind the breakwaters may recover, The area around the breakwater is often scoured. In addition to the current island management, the conservation of remote islands, as well as the conservation of the land where the coral gravel around the surface accumulates to the surface of the water, and if land can be newly formed using coral gravel, It can contribute to national land conservation.

  Although a plurality of technologies have been proposed for corals as in Patent Literatures 1 to 7, there has not been proposed any technology for land conversion using coral gravel. That is, Patent Literatures 1 to 5 aim at relocating, multiplying, and protecting living corals. However, since corals live only under water, it is difficult to land them by these methods. Further, the method of Patent Document 6 merely prevents scattering of coral gravel deposited on the water bottom, and the deposition effect due to this is not expected. Further, the structure and method of Patent Document 7 provide a coral growing body by storing coral limestone in a net-like cage whose entire surface is substantially closed, and does not promote the accumulation. Furthermore, in the natural world, land can be landed with coral gravel, but there is no technology for forming land using coral gravel at the intended location.

  The present invention has been made in view of the above-mentioned problems of the related art, and has as its object to provide a land-based method by coral gravel accumulation, and a permeable structure and a structure therefor.

The land-based method by coral gravel accumulation to achieve the above object is a method of accumulating coral gravel and land, so that a planar capturing portion having a plurality of openings capable of capturing coral gravel rises from the bottom of the water. permeable structures, water masses are placed in a direction which can pass through the plurality of openings of the planar catching section, the acquisition unit when the water mass is passed through a plurality of openings of the catching part is the water provided to the The coral gravel in the mass is captured, and the captured coral gravel is deposited on the front side of the capturing unit .

  According to the land-based method based on coral gravel accumulation, the permeable structure can capture coral gravel that moves with the movement of the water mass while penetrating the water mass that moves due to waves, tides, and the like. The captured coral gravel accumulates, and the water mass continues to act due to the permeability within the coral gravel until the sediment reaches a certain thickness, and subsequently the coral gravel moves and accumulates. Then, as the thickness of the coral gravel increases and the permeability decreases, the deposited coral gravel becomes new underground, and the water mass moves to a higher position. As a result, the coral gravel gradually moves to the higher position. accumulate. In this way, as the coral debris continues to be deposited, land deposition is realized by the deposited coral debris.

In Rikuka method according to the coral gravel deposition, substantially are preferably installed so as to be orthogonal to the moving direction of the catching portion is the water mass. Thereby, coral gravel can be efficiently captured and deposited.

  In addition, coral gravel existing around the planned installation position of the permeable structure is sampled, and the longitudinal dimension and the lateral dimension of the collected coral gravel are measured, and the average dimension is determined from the measurement results. It is preferable to calculate and set the size of the opening based on the average size. An average size close to the actual coral gravel can be obtained, and the coral gravel can be trapped more efficiently.

  In addition, it is preferable that the size of the opening is set to be equal to or less than the longitudinal dimension and equal to or greater than the short dimension of the average dimension.

The permeable structure for achieving the above object is a permeable structure for accumulating coral gravel and landing, and a planar capturing portion having a plurality of openings capable of capturing coral gravel from the bottom of the water. In order to stand up, the size of the opening is equal to or less than the longitudinal dimension and the minor dimension of the average size of the coral gravel, and is in a direction in which a water mass can pass through the plurality of openings of the planar capturing portion. Installed, when the water mass passes through the plurality of openings of the capturing portion, the capturing portion captures coral gravel in the water mass, and deposits the captured coral gravel on the front side of the capturing portion. Things.

  According to this permeable structure, it is possible to capture coral gravels that move with the movement of the water mass while penetrating the water mass that moves due to waves, tides, and the like. The captured coral gravel accumulates, and the water mass continues to act due to the permeability within the coral gravel until the sediment reaches a certain thickness, and subsequently the coral gravel moves and accumulates. Then, as the thickness of the coral gravel increases and the permeability decreases, the deposited coral gravel becomes new underground, and the water mass moves to a higher position. As a result, the coral gravel gradually moves to the higher position. accumulate. In this way, as the coral debris continues to be deposited, land deposition is realized by the deposited coral debris.

In addition, a plurality of the capturing units whose top end heights are sequentially changed may be arranged at predetermined intervals.

Further, the average size of the coral gravel, for example, be a dimension obtained from the average dimensions and historical data such as described above.

  A structure for achieving the above object is a structure for accumulating coral gravel and lands it, and includes a plurality of the above-described permeable structures.

  According to this structure, by installing a plurality of permeable structures, land can be expected due to the accumulation of coral gravel in a wider area.

  A first structure as the above-mentioned structure is a structure for accumulating coral gravel and making it land, and includes a plurality of the above-mentioned permeable structures, and the plurality of permeable structures are arranged in a row in a horizontal direction. It was installed side by side. According to this structure, land formation due to the accumulation of coral gravel can be expected in a wider range.

  Similarly, the second structure is a structure for accumulating coral gravel and lands, and includes a plurality of the above-described permeable structures, and the plurality of permeable structures are separated in the moving direction of the water mass. It was installed. According to this structure, when the permeable structures are installed alone or in multiple rows, deposition is promoted if the moving direction of the water mass is uniform, but the movement of the water mass is reversed depending on the period. In such a case, it is expected that the deposited coral gravel will be destroyed. Therefore, by installing multiple permeable structures separated in the direction of movement of the body of water, even if the movement of the body of water is reversed, the capture of coral gravel in the space between each permeable structure It becomes possible.

  Similarly, the third structure is a structure for accumulating coral gravel and lands, and includes a plurality of the above-described permeable structures, and a plurality of the permeable structures are arranged in a row in a horizontal direction. Further, a plurality of the permeable structures are arranged in a line in a lateral direction at a distance in the moving direction of the water mass, and a plurality of the lines are arranged at a distance in the moving direction. According to this structure, it is expected that coral debris will accumulate and land on a wider area, and even if the movement of the water mass is reversed, it is possible to capture coral debris in the space between each row. Become.

  In the second and third structures, the permeable structures installed apart from each other in the moving direction have their top ends sequentially increasing in height from upstream to downstream in the moving direction. It is preferable to be configured as follows. Even if the water mass moves in the opposite direction, the top height is lowered on the upstream side in the direction of movement of the water body and the height of the top end is increased toward the downstream side in the movement direction. The capture of coral gravel in the space between structures is more efficient.

  Similarly, the fourth structure is a structure for accumulating coral gravel and landing, and includes a plurality of the above-described permeable structures, and is installed so that a plurality of the permeable structures surround an area. And the plurality of permeable structures are installed so as to surround the plurality of permeable structures surrounding the one area. Examples of planar installation shapes of such structures include, for example, concentric circles, squares, rectangles, polygons, and ellipses.

  In the fourth structure, it is preferable that each of the transparent structures is configured such that a height of a top end thereof is gradually reduced from an inside to an outside of the one region.

  In each of the above structures, it is preferable that the permeable structure be fixed to the water bottom so as not to move.

  ADVANTAGE OF THE INVENTION According to this invention, the landslide method by coral gravel accumulation, the permeation | transmission structure and the structure for it can be provided.

FIG. 2 is a perspective view illustrating a basic configuration of a transparent structure according to the first embodiment. FIG. 2 is a side view of the permeable structure 10 of FIG. 1 installed on a water floor, schematically illustrating processes (a) to (d) in which coral gravel is captured and deposited. FIG. 4 is a side view schematically illustrating a transparent structure according to a second embodiment. It is a side view (a) (b) of a transparent structure for explaining a problem at the time of installing the transparent structure of FIG. 1 independently. FIG. 10 is a side view schematically showing a structure according to another example of the second embodiment. It is a perspective view showing roughly the structure by a 3rd embodiment. It is a perspective view showing roughly the structure by other examples of a 3rd embodiment. FIG. 8A is a plan view schematically illustrating a structure according to a fourth embodiment, and FIG. 8B is a diagram illustrating the structure taken along line VIIIB-VIIIB. It is a schematic plan view for explaining an operation effect by a 4th embodiment. 2 is a side view similar to FIG. 2 and schematically illustrates processes (a) to (e) in which coral gravel is captured and deposited when the height of the top of the permeable structure 10 is lower than the water surface height. FIG. 4 is a perspective view illustrating a basic configuration of a transparent structure according to another first example of the first embodiment. It is a perspective view which shows the basic structure of the transmissive structure by another 2nd example of 1st Embodiment. It is a perspective view showing roughly the structure by another example of a 3rd embodiment. FIG. 7 is a perspective view schematically showing a structure in which still another plurality of permeable structures of the first embodiment are arranged in the same manner as in FIG. 6. FIG. 15 is a perspective view schematically showing another structure in which another plurality of transmissive structures having the same curved portions as those in FIG. 14 are arranged in the same manner as in FIG. 13.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a perspective view showing a basic configuration of the transparent structure according to the first embodiment. In FIG. 1 and the like, the openings and coral gravel are exaggerated for convenience of explanation.

  As shown in FIG. 1, the permeable structure 10 according to the present embodiment includes a bottom plate 11 and a vertical portion 12 provided substantially perpendicular to the bottom plate 11. The vertical portion 12 is configured as a capturing portion in a planar shape or a flat plate shape, and has a large number of openings 13 formed in a flat surface.

  The size of the opening 13 is set to be equal to or less than the longitudinal size of the representative size of the coral gravel and equal to or more than the short size. Thereby, the coral pebbles can be efficiently captured by the large number of openings 13 provided in the vertical portion 12 while passing through the water mass. Here, the representative dimension is the average longitudinal direction calculated by statistical processing by collecting coral gravel around the planned installation position of the permeable structure 10 and measuring the dimensions in the longitudinal and lateral directions. And the length in the lateral direction. In addition, for example, the size of the opening may be set based on past data and the like regarding the size of the coral gravel.

  The vertical portion 12 can be configured by, for example, providing a plate-shaped mesh member. The large number of openings 13 are formed of a mesh of a mesh member, and the size of the openings 13 corresponds to the mesh size of the mesh member. In the above example, the mesh size is selected to be less than or equal to the longitudinal dimension and greater than or equal to the minor dimension of the average size of coral gravel.

  The permeable structure 10 of FIG. 1 is installed on the water bottom G such that the bottom plate 11 is horizontal, and a vertical portion 12 having a number of openings 13 stands in a vertical direction. At this time, the vertical portion 12 is positioned so that its plane is orthogonal to the moving direction x of the water mass such as a wave or a tide. The permeable structure 10 is fixed to the water bottom G by a fixing means (not shown) such as an anchor at the bottom plate portion 11 so as not to move.

  Next, the operation and effect of the transparent structure 10 of FIG. 1 will be described with reference to FIG. FIG. 2 is a side view of the permeable structure 10 of FIG. 1 installed on the water floor, and schematically illustrates processes (a) to (d) in which coral gravel is captured and deposited.

  As shown in FIG. 2A, a water mass moving due to a wave, a tide, or the like flows in the moving direction x so as to be substantially orthogonal to the vertical portion 12 of the permeable structure 10, and passes through many openings 13. The coral pebble 1 that has moved in the water due to the movement of the water mass is captured by the many openings 13, and as shown in FIG. 2B, the captured coral pebble 1 starts to accumulate on the bottom plate portion 11 and its surroundings. The water mass continues to act on the many openings 13 due to the permeability of the deposited coral gravel until a certain sediment thickness is reached, and the coral gravel 1 continues to move with the water mass and is trapped and accumulated in the many openings 13. to continue.

  As shown in FIG. 2 (c), when the thickness of the coral gravel 1 increases and the coral gravel 1 becomes the coral gravel deposit 2 and the permeability decreases, the coral gravel deposit 2 becomes fresh underground. As a result, the height at which the water mass flows becomes higher than the upper surface of the coral gravel deposit 2. As a result, the coral gravel 1 sequentially accumulates at a higher position, and the upper surface of the coral gravel deposit 2 rises.

  As shown in FIG. 2 (d), as the accumulation of coral gravel 1 progresses, the upper surface of the coral gravel deposit 2 gradually increases, and the foreshore slope where the lower portion of the coral gravel deposit 2 becomes wider and the upper portion becomes narrower. Is formed. Therefore, while the moving direction of the water mass gradually changes in the obliquely upward direction x ′, if the top end of the permeable structure 10 is at a position higher than above the water surface, the coral gravel 1 Is launched and deposited on the water surface, and as a result, the upper surface of the coral gravel deposit 2 is exposed from the water surface.

  In other words, the coral pebble 1 can be deposited on the water surface while forming a foreshore gradient where the sedimentary action off the shore generated by the waves and the erosion action are balanced. In addition, it is known that the foreshore slope is low on a normal sandy beach in high waves, and becomes steep when calm. In other words, the coastal terrain shifts to a more stable shape according to the characteristics of the incoming waves. The slope of the coast off the coast at this time is called the foreshore slope. The foreshore gradient also varies depending on the grain shape of the sediment.

  As described above, according to the present embodiment, in the area where the permeable structure 10 is installed, the coral pebble 1 that moves along with the water mass in the water is captured and deposited, whereby land can be formed. That is, only by installing the permeable structure 10, land use by the coral gravel 1 is promoted by utilizing a natural external force, and conservation of a remote island is achieved.

  Further, as shown in FIGS. 2A to 2D, when the top height H (FIG. 1) of the permeable structure 10 is higher than the water surface height, the top of the permeable structure 10 is higher than above the water surface. At a high position, coral gravel is launched to the surface of the water and accumulates, making it easier to realize land formation by coral gravel accumulation.

  Further, the deposition when the top end height of the transparent structure 10 is lower than the water surface height will be described with reference to FIG. FIG. 10 is a side view similar to FIG. 2 and schematically illustrates processes (a) to (e) in which coral gravel is captured and deposited when the top of the permeable structure 10 is lower than the water level. Show.

  As shown in FIGS. 10 (a) to 10 (d), initially, coral gravel 1 is deposited on the front surface of the permeable structure 10 as in FIGS. 2 (a) to 2 (c), and as in FIG. 2 (d). After the upper surface of the coral gravel deposit 2 reaches the top end of the permeable structure 10, the coral gravel 1 passes over the upper part of the permeable structure 10 as shown in FIG. Coral gravel deposits 2 ′ are deposited on the rear surface, and thereafter, the coral gravel 1 is deposited on the rear side of the permeable structure 10 as shown in FIG. In this way, land formation due to the accumulation of coral gravel 1 is more easily realized.

  In the case of FIG. 2, as shown in FIG. 2D, after the upper surface of the coral pebble deposit 2 reaches the top end of the permeable structure 10, the coral pebble 1 further continues to be deposited. e) Similar to (f), the accumulation of the coral gravel 1 also proceeds on the back side of the permeable structure 10.

  The operation and effect of the present embodiment will be further described. If an impervious structure is installed instead of the impervious structure as shown in FIG. 1, the periphery of the impervious structure will be scoured, and the effect is completely opposite to the sedimentation. Becomes

  In addition, in the case of sand, since the particle size is small, the opening of the permeable structure that captures the sand becomes small, thereby hindering the movement of the water mass. As a result, a phenomenon similar to the case in which the impermeable structure is installed occurs, and the sand does not accumulate on the front surface of the transparent structure for sand, and the accumulation effect as in the present embodiment is obtained. Not satisfied.

  Next, another two examples according to the present embodiment will be described with reference to FIGS. FIG. 11 is a perspective view showing a basic configuration of a transparent structure according to another first example of the present embodiment. FIG. 12 is a perspective view showing a basic configuration of a transmissive structure according to another second example of the present embodiment.

  As shown in FIG. 11, the transparent structure 16 is provided with support members 14, 14 such that the bottom plate portion 11 of FIG. 1 is omitted and the lower ends of both ends of the vertical portion 12 project perpendicularly to the vertical portion 12. It is a thing. The vertical portion 12 is supported at its lower ends at both ends by support members 14, 14 extending forward and backward of the vertical portion 12. In addition, the permeable structure 16 is fixed to the water bottom by fixing means (not shown) such as anchors with the support members 14 and 14.

  As shown in FIG. 12, the permeable structure 17 does not include the bottom plate portion 11 of FIG. 1 and the vertical piles 15, 15 are cast on the water bottom at the installation position, and the vertical portion 12 has the vertical piles 15, 15 at both ends. It is designed to be fixed and supported. In the example of FIG. 12, a fixing means such as an anchor becomes unnecessary.

[Second embodiment]
FIG. 3 is a side view schematically showing a transparent structure according to the second embodiment. 4A and 4B are side views (a) and (b) for explaining a problem when the transparent structure of FIG. 1 is installed alone.

  The transmissive structure 20 of FIGS. 3A and 3B has the same configuration as that of FIG. 1 except that a plurality of vertical portions 21, 22, 23, and 24 are provided on a bottom plate 25 at predetermined intervals. I do. Each of the vertical portions 21, 22, 23, and 24 has a lower top end in this order, and has a large number of openings as in FIG.

  As shown in FIG. 3A, in the case where the normal movement of the water mass is the movement direction x, the permeable structure 20 has a vertical portion 24 having a low top end located upstream in the movement direction x, Vertical portions 23, 22, 21 having a higher top end are arranged in order toward the downstream side in the moving direction x.

  Here, a problem when the transparent structure 10 of FIG. 1 is installed alone will be described. As shown in FIG. 4A, if the moving direction x of the water mass is uniform, the accumulation of the coral gravel 1 is promoted. However, as shown in FIG. 4 (b), when the moving direction of the water mass changes in the opposite direction ax depending on the period, there is a possibility that the coral gravels accumulated up to that time may be destroyed by the movement of the water mass. is there.

  In order to solve the above-described problem, according to the present embodiment, the vertical portions 24, 23, 22, and 21 are set such that the height of the top is lowered on the upstream side in the moving direction x of the water mass and the downstream side in the moving direction x. As shown in FIG. 3 (b), even if the movement of the water mass is in the opposite direction ax to the moving direction x, the plurality of vertical portions 21 to 21 are arranged. 24 can capture and accumulate coral gravel in each space adjacent to each other, and also can prevent the water mass from moving in the movement direction x and moving and destroying coral gravel.

  FIG. 5 is a side view schematically showing a structure according to another example of the present embodiment. The structure 30 shown in FIG. 5 includes a plurality of permeable structures 10A, 10B, 10C, and 10D. The plurality of permeable structures 10A to 10D are arranged on the bottom of the water in the moving direction x of the water mass. The basic structure of each of the transparent structures 10A to 10D is the same as that of the transparent structure 10 of FIG. 1, but their vertical portions 12a, 12b, 12c, and 12d are configured such that their top ends are sequentially reduced in height. Each has a number of openings as in FIG.

  According to the structure 30 of FIG. 5, the permeable structures 10A to 10D are arranged such that the tops of the vertical portions 12a, 12b, 12c, and 12d become lower in order from the downstream side in the moving direction x of the water mass. 3A and 3B, it is possible to obtain the same operation and effect as the transparent structure 20 having a plurality of vertical portions in FIGS. Even if it becomes, the vertical portions 12a to 12d of the plurality of permeable structures 10A to 10D can capture and accumulate coral gravel in each adjacent space, and the water mass moves in the movement direction x. It is possible to prevent the accumulated coral gravel from moving and being destroyed.

  In FIGS. 3 and 5, the interval between the vertical portions of the permeable structure is preferably set appropriately so that the accumulation of coral gravel and the prevention of the destruction of the deposited coral gravel can be efficiently realized. .

[Third Embodiment]
FIG. 6 is a perspective view schematically showing a structure according to the third embodiment. The structure 40 in FIG. 6 is composed of a plurality of permeable structures 10, and the plurality of permeable structures 10 are arranged in a row in the horizontal direction on the water bottom G so as to be orthogonal to the moving direction x of the water mass. Things. Each of the transparent structures 10 has the same configuration as that of FIG. 1, and each of the vertical portions 12 has a number of openings 13. According to the structure 40 of FIG. 6, by arranging the plurality of permeable structures 10 in a row in the horizontal direction, it is possible to expect the capture and accumulation of coral gravel in a wide range.

  FIG. 7 is a perspective view schematically showing a structure according to another example of the present embodiment. The structure 50 shown in FIG. 7 includes a plurality of permeable structures 10A, a plurality of permeable structures 10B, and a plurality of permeable structures 10C. A plurality of transmissive structures 10B are arranged in a row in the horizontal direction so as to be orthogonal to the moving direction x, and a plurality of transmissive structures 10B are arranged in a row b in the lateral direction so as to be orthogonal to the moving direction x. Are also arranged side by side in a row c so as to be orthogonal to the moving direction x. Each of the transmissive structures 10A to 10C has the same basic configuration as the transmissive structure 10 of FIG. 1, but their vertical portions 12a, 12b, and 12c have their top ends decreasing in order. . Each of the vertical portions 12a to 12c has a large number of openings 13.

  The structure 50 in FIG. 7 is configured by arranging the rows a to c of the plurality of permeable structures 10A to 10C in the moving direction x of the water mass. Each of the permeable structures 10A to 10C in each of the rows a to c is installed such that the tops of the vertical portions 12a, 12b, and 12c become lower in order from the downstream side in the moving direction x of the water mass.

  Since the structure 40 in FIG. 6 only has a plurality of permeable structures 10 arranged in a row in the horizontal direction, if the moving direction of the water mass changes in the opposite direction depending on the time, the structures 40 in FIG. 7) has the same problems as those described in FIG. 7, but according to the structure 50 of FIG. 7, the same operation and effects as those of FIGS. Even if the direction becomes opposite to x, the vertical portions 12a to 12c of the rows a to c can capture and accumulate coral debris in adjacent spaces, and the water mass moves in the movement direction x. It is possible to prevent coral gravel that has accumulated and moved from being destroyed. As a result, even when the moving direction of the water mass changes in the opposite direction depending on the time, the capture and accumulation of coral gravel can be expected in a wide range.

  Next, still another example according to the present embodiment will be described with reference to FIG. FIG. 13 is a perspective view schematically showing a structure according to still another example of the present embodiment. The structure 70 shown in FIG. 13 includes a plurality of permeable structures 17 using the vertical piles 15 shown in FIG. 12 arranged in a row in the horizontal direction at right angles to the moving direction x of the water mass in the same manner as in FIG. It was set up side by side. In the structure 70, the adjacent vertical portions 12 are fixed to and supported by the common vertical pile 15. According to the structure 70, the same effect as in FIG. In addition, by arranging the structure 70 in FIG. 13 in the same manner as in FIG. 7 and installing the structure so that the height of the top of the vertical portion becomes lower in order, the same effect as in FIG.

  Note that the plurality of transparent structures 16 in FIG. 11 may be installed in the same manner as in FIG. 6, or may be installed in the same manner as in FIG.

[Fourth embodiment]
FIG. 8 is a plan view schematically showing a structure according to the fourth embodiment, and FIG. 8B is a view cut along line VIIIB-VIIIB. FIG. 9 is a schematic plan view for explaining the function and effect of the present embodiment.

  The structure 60 in FIGS. 8A and 8B includes a plurality of structures 61, 62, and 63. The structure 61 surrounds a large number of transmissive structures 61A in one plane area M of the water bottom. The structure 62 is formed by arranging a large number of transmissive structures 62A in a square so as to surround the structure 61. 63 is configured by arranging a large number of transmissive structures 63 </ b> A in a planar square shape so as to surround the structure 62.

  The transmissive structures 61A to 63A have the same basic configuration as the transmissive structure 10 of FIG. 1, but as shown in FIG. 8B, their vertical portions 61a, 62a, 63a The height decreases in order from the inside to the outside. Each of the vertical portions 61a to 63a has a large number of openings as in FIG.

  According to the structure 60 of FIG. 8, since the depth of the surroundings of the coral gravel is locally reduced, the waves from the moving direction x are refracted and concentrated behind them as shown in FIG. As a result, coral gravel moves from the left and right on the back surface 65 of the structure 60, and the concentration of such waves further promotes the accumulation of coral gravel in the region N formed on the back surface 65 side. As a result, land formation by capturing and accumulating coral gravel is performed efficiently. In addition, by installing the structure 60 at a point where a moving direction of a water mass such as a wave or a tidal current changes depending on a period and acts from a plurality of directions, coral gravel is efficiently captured and deposited.

  In FIG. 8, a large number of transparent structures are arranged in a square shape in a plane, but the present invention is not limited to this, and may be arranged in a concentric shape, a rectangular shape, a polygonal shape, an oval shape, or the like.

  The embodiments for carrying out the present invention have been described above, but the present invention is not limited to these, and various modifications can be made within the technical idea of the present invention. For example, a plurality of the permeable structures 10 and 20 of FIGS. 1 and 3 of the present embodiment can be continuously installed, but such installation may be performed not only at one place but also at a plurality of places apart from each other. . Similarly, the structures 30, 40, 50, and 60 shown in FIGS. 5 to 8 may be installed not only at one place but also at a plurality of places apart from each other.

  Further, the number of the plurality of vertical portions in FIG. 3, the number of the plurality of transparent structures in FIG. 5, and the number of the plurality of rows in FIG. 7 are not limited to the illustrated numbers, and can be increased or decreased as needed. is there. Also, the number of transmissive structures arranged in a row in the horizontal direction in FIGS. 6 and 7 can be similarly increased or decreased as needed.

  Further, in FIGS. 1, 11 and 12, the vertical portion 12 which is the capturing portion having the plurality of openings 13 is formed in a flat plate shape. However, the present invention is not limited to this. The planar capturing portion includes not only a planar capturing portion and a planar capturing portion having an entire surface but also, for example, a capturing portion configured in advance into a deformed shape such as a V shape or a wavy shape.

  Further, when the capturing portion is made of, for example, a flat plate or an expanded metal made of a steel material, it has a certain degree of rigidity, so that it almost maintains a flat shape during operation, but for example, it can be made of a resin material or a wire mesh. When it is made of a flexible material in a planar shape, it may be deformed into a curved shape by the movement of the water mass during operation.

  FIG. 14 shows a structure 80 in which a plurality of permeable structures 18 provided with a capturing portion 12 ′ having a plurality of openings 13 on the bottom plate portion 11 are arranged in a row in the horizontal direction similarly to FIG. 6. In FIG. 15, a plurality of vertical piles 15 are cast on the bottom of the water, and a plurality of permeable structures 19 in which the capturing portions 12 'are fixed and supported by the vertical piles 15 are arranged in a row in the horizontal direction similarly to FIG. The structures 90 are shown in FIG. 14 and 15 are made of a flexible material such as a resin material or a wire mesh, and are flat when installed, and are erected in the vertical direction. The lump may be deformed in the movement direction x due to the movement of the lump and may be concavely curved.

  The vertical portion 12 in FIGS. 1, 11, and 12, and the capturing portion 12 'in FIGS. 14 and 15 are vertically erected, but the present invention is not limited to this. May be inclined back and forth with respect to the moving direction of the camera. That is, in the present invention, the planar capturing portion having a plurality of openings may be entirely inclined with respect to the vertical direction.

  The coral pebbles in this specification are derived from coral reefs, and often have a shape like a tree branch or a table.

  ADVANTAGE OF THE INVENTION According to this invention, since the method of accumulating coral gravels and making it land, and the permeation | transmission structure and structure which can be used for that can be provided, it becomes possible to construct a new island.

1 Coral gravel 2 Coral gravel deposits 10, 16, 17, 18, 19, 20 Permeable structures 10A, 10B, 10C, 10D Permeable structures 11 Bottom plate 12 Vertical part (capture part)
12 'capture parts 12a, 12b, 12c, 12d vertical part (capture part)
13 Openings 21, 22, 23, 24 Vertical part (capture part)
25 Bottom plate part 30, 40, 50, 60, 70, 80, 90 Structures a to c One row G Water bottom M One plane area x Moving direction
ax reverse direction

Claims (5)

A method of accumulating coral gravel and land,
A permeable structure provided with a planar capturing section having a plurality of openings capable of capturing coral gravel so as to rise from the bottom of the water is installed in a direction in which a water mass can pass through the plurality of openings of the planar capturing section. ,
When the water mass passes through the plurality of openings of the capturing portion, the capturing portion captures the coral debris in the water mass,
Landing method by coral gravel accumulation in which the captured coral gravel is deposited on the front side of the capturing unit.   2. The method according to claim 1, wherein the capturing unit is installed so as to be substantially orthogonal to a moving direction of the water mass. 3. Collect coral gravel around the planned installation position of the permeable structure,
Measure the longitudinal and transverse dimensions of the coral gravel collected,
Calculate the average size from the measurement results,
The method according to claim 1 or 2, wherein the size of the opening is set based on the average size. A permeable structure for depositing and land coral gravel,
Equipped with a planar catching section with multiple openings that can capture coral gravel so as to rise from the bottom of the water,
The size of the opening is less than or equal to the length of the average size of the coral gravel and more than the width of the short dimension,
Water mass is installed in a direction that can pass through a plurality of openings of the planar capturing unit,
When the water mass passes through the plurality of openings of the capturing portion, the capturing portion captures the coral debris in the water mass,
A permeable structure for depositing the captured coral gravel on the front side of the capturing unit. A structure for accumulating coral gravel and landing,
A structure comprising a plurality of the transparent structures according to claim 4 .

Images