JP2016127819A - Emergence method utilizing coral gravel accumulation, and permeable structure and structure for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an emergence method utilizing coral gravel accumulation, and a permeable structure and a structure for the same.SOLUTION: An emergence method utilizing coral gravel accumulation is a method for achieving emergence by accumulating coral gravel. A permeable structure 10 having a plurality of openings 13 capable of capturing the coral gravel 1 is installed in the direction of enabling the passage of a water mass. The coral gravel is accumulated by capturing the coral gravel in such a manner as to make the water mass pass through the openings of the permeable structure.SELECTED DRAWING: Figure 1

Description

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

  There are about 500 remote islands that serve as the starting point for Japan's territorial waters and exclusive economic zone (EEZ), but it is necessary to strengthen the maintenance and management of remote islands in order to protect the bottom and marine resources. On remote islands, the need for coral reef conservation and utilization is recognized, such as coral reefs surrounding the island. For example, Patent Documents 1 and 2 are relocation of coral reefs, Patent Documents 3 and 4 are propagation of coral reefs, Patent Document 5 is breeding and protection of corals, Patent Document 6 is prevention of scattering of coral gravel fragments, and Patent Document 7 is coral reefs. Propose each technique such as construction of a breeding structure.

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

  In the vicinity of remote islands where coral reefs are prominent, dead corals become sand gravel, and there are places where coral gravel forms islands due to atmospheric conditions. In addition, for the purpose of coastal protection, a breakwater made of stone or blocks may be constructed at the point where coastal erosion is dominant, but the sandy beach behind the breakwater may be restored. Often, the area around the offshore bank is scoured. In addition to the maintenance of the current island, the preservation of the remote islands, as well as the preservation of the land where the coral gravel around the water has accumulated to the surface of the water, if the land can be formed using new coral gravel, Contribute to national land conservation.

  Although several techniques are proposed about coral like patent documents 1-7, there is still no proposal about the technique which makes land using coral gravel. In other words, Patent Documents 1 to 5 are intended to relocate, proliferate, and protect living corals, but corals inhabit only under the surface of the water, and it is difficult to make them land by these methods. Moreover, the method of patent document 6 is only prevention of the scattering of the coral gravel deposited on the water bottom, and the depositing effect by this cannot be expected. Moreover, the structure and method of Patent Document 7 provide a coral cultivated body by storing coral limestone in a frame-like body that is substantially closed over the entire surface, and does not promote deposition. Furthermore, in the natural world, coral gravel is sometimes used to land, but there is still no technology for forming land using coral gravel at the intended location.

  An object of this invention is to provide the landing method by coral gravel deposition, the permeation | transmission structure, and a structure for it in view of the problem of the prior art as mentioned above.

  The land-based method by coral gravel deposition to achieve the above objective is a method of depositing coral gravel and landing it, allowing water masses to pass through a permeable structure that can capture coral gravel. The coral gravel is deposited by passing the water mass through the opening of the permeable structure and capturing the coral gravel.

  According to this landing method by coral gravel deposition, the permeable structure can capture the coral gravel that moves along with the movement of the water mass while passing through the water mass that moves due to waves and tidal currents. The trapped coral gravel accumulates, and the water mass continues to act due to the permeability in the coral gravel until a certain thickness is reached, and the coral gravel moves and accumulates. And when the sedimentation thickness of coral gravel increases and the permeability decreases, the accumulated coral gravel becomes a new submarine ground, the water mass moves to a higher position, and as a result, the coral gravel gradually increases to a higher position. accumulate. In this way, the accumulation of coral gravel continues, and landing is realized by the accumulated coral gravel.

  In the above landing method by coral gravel deposition, the permeable structure includes a planar capturing part having the opening, and the capturing part is installed so as to be substantially orthogonal to the moving direction of the water mass. Is preferred. 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, the longitudinal dimension and the lateral dimension of the collected coral gravel are measured, and an average dimension is determined from the measurement result. It is preferable to calculate and set the size of the opening based on the average dimension. An average size approximate to actual coral gravel can be obtained, and coral gravel can be captured more efficiently.

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

  A permeable structure for achieving the above object is a permeable structure for depositing and landing coral gravel, having a plurality of openings capable of capturing the coral gravel and allowing a water mass to pass through. By being installed in the direction, the water mass passes through the opening and the coral gravel is captured.

  According to this permeable structure, the coral gravel that moves along with the movement of the water mass can be captured while it passes through the water mass that moves due to waves and tidal currents. The trapped coral gravel accumulates, and the water mass continues to act due to the permeability in the coral gravel until a certain thickness is reached, and the coral gravel moves and accumulates. And when the sedimentation thickness of coral gravel increases and the permeability decreases, the accumulated coral gravel becomes a new submarine ground, the water mass moves to a higher position, and as a result, the coral gravel gradually increases to a higher position. accumulate. In this way, the accumulation of coral gravel continues, and landing is realized by the accumulated coral gravel.

  The permeable structure preferably includes a planar capturing part having the opening. Moreover, you may make it arrange | position the several said capture | acquisition part which changed the top end height in order at a predetermined space | interval.

  Moreover, it is preferable that the size of the said opening is below the longitudinal dimension of the average dimension of the said coral gravel, and above the short dimension. In addition, the average dimension of coral gravel may be a dimension obtained from the above-mentioned average dimension or past data, for example.

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

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

  The first structure as the structure is a structure for depositing and landing coral gravel, and includes a plurality of the permeable structures described above, and the plurality of permeable structures are arranged in a row in a lateral direction. It was installed side by side. According to this structure, land formation by coral gravel accumulation can be expected in a wider range.

  Likewise, the second structure is a structure for depositing and landing coral gravel, and includes a plurality of the permeable structures described above, and the plurality of permeable structures are separated in the movement direction of the water mass. It is installed. According to this structure, when permeable structures are installed singly or in a plurality of rows, deposition is promoted if the movement direction of the water mass is uniform, but the movement of the water mass is reversed depending on the period. If this happens, it is expected that the accumulated coral gravel will be destroyed. Therefore, by installing multiple permeable structures apart in the direction of movement of the water mass, even if the movement of the water mass is reversed, the coral gravel is captured in the space between each permeable structure. It becomes possible.

  Similarly, the third structure is a structure for depositing and landing coral gravel, and includes a plurality of the above-described permeable structures, and a plurality of the permeable structures are arranged in a row in the lateral direction. In addition, a plurality of the permeable structures are arranged apart from each other in the movement direction so as to be arranged in a row in the lateral direction apart from the movement direction of the water mass. According to this structure, land can be expected to be landed by coral gravel in a wider range, and even if the movement of water mass is reversed, coral gravel can be captured in the space between each row. Become.

  In the second and third structures, the permeable structures placed apart in the moving direction have their top heights sequentially increased from the upstream side to the downstream side in the moving direction. It is preferable to be configured as described above. Even if the water mass moves in the opposite direction by decreasing the top height on the upstream side in the direction of movement of the water mass and increasing the top height as it goes downstream in the direction of movement, each permeability Coral gravel capture in the space between structures is more efficient.

  Similarly, the fourth structure is a structure for depositing coral gravel and landing, and includes a plurality of the above-described permeable structures, and the plurality of permeable structures are installed so as to surround one area. Further, a plurality of the permeable structures are installed so as to surround the plurality of permeable structures surrounding the one region. 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 permeable structures is configured such that the height of the top end thereof is sequentially decreased from the inner side where the one region is located toward the outer side.

  In each of the above structures, the permeable structure is preferably fixed to the bottom of the water so as not to move.

  ADVANTAGE OF THE INVENTION According to this invention, the landing method by coral gravel deposition, the permeable structure for it, and a structure can be provided.

It is a perspective view which shows the basic composition of the permeable structure by 1st Embodiment. It is a side view of the permeable structure 10 of FIG. 1 installed in the bottom of the water, and schematically shows processes (a) to (d) in which coral gravel is captured and deposited. It is a side view which shows roughly the permeable structure by 2nd Embodiment. It is a side view (a) (b) of the permeable structure for demonstrating the problem at the time of installing the permeable structure of FIG. 1 independently. It is a side view which shows roughly the structure by another example of 2nd Embodiment. It is a perspective view which shows roughly the structure by 3rd Embodiment. It is a perspective view which shows roughly the structure by another example of 3rd Embodiment. It is the top view (a) which shows schematically the structure by 4th Embodiment, and the figure (b) seen by cut | disconnecting in the VIIIB-VIIIB line direction. It is a schematic plan view for demonstrating the effect by 4th Embodiment. 2 is a side view similar to FIG. 2, schematically showing processes (a) to (e) in which coral gravel is trapped and deposited when the top height of the permeable structure 10 is lower than the water surface height. It is a perspective view which shows the basic composition of the permeable structure by another 1st example of 1st Embodiment. It is a perspective view which shows the basic composition of the permeable structure by another 2nd example of 1st Embodiment. It is a perspective view which shows roughly the structure by another example of 3rd Embodiment. It is a perspective view which shows roughly the structure which arranged another some permeable structure of 1st Embodiment similarly to FIG. FIG. 15 is a perspective view schematically showing another structure in which another plurality of permeable structures having curved portions similar to 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 a permeable structure according to the first embodiment. In addition, in FIG. 1 etc., the opening 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 portion 11 and a vertical portion 12 provided substantially perpendicular to the bottom plate portion 11. The vertical portion 12 is configured in a planar shape or a flat plate shape as a capturing portion, and a large number of openings 13 are formed in the plane.

  The size of the opening 13 is not more than the longitudinal dimension of the representative dimension of the coral gravel and not less than the short dimension. Thereby, the coral gravel can be efficiently captured while allowing the water mass to pass through the large number of openings 13 provided in the vertical portion 12. Here, the representative dimension is an average longitudinal direction calculated by statistical processing by collecting coral gravel existing around the planned installation position of the permeable structure 10 and measuring the longitudinal and lateral dimensions. And the length in the short direction. For example, the size of the opening may be set based on past data regarding the size of the coral gravel.

  The vertical portion 12 can be configured by providing a flat mesh member, for example, and a large number of openings 13 are formed of a mesh of the mesh member, and the size of the opening 13 corresponds to the mesh size of the mesh member. In the above example, the mesh size is selected to be equal to or smaller than the long dimension of the average dimension of the coral gravel and larger than the short dimension.

  The permeable structure 10 of FIG. 1 is installed on the water bottom G so that the bottom plate portion 11 is horizontal, and a vertical portion 12 having a large number of openings 13 stands in the vertical direction. At this time, the vertical portion 12 is positioned so that the plane thereof is orthogonal to the movement direction x of the water mass such as a wave or a tidal current. 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 effect of the permeable structure 10 of FIG. 1 is demonstrated with reference to FIG. FIG. 2 is a side view of the permeable structure 10 of FIG. 1 installed at the bottom of the water, and schematically shows processes (a) to (d) in which coral gravel is captured and deposited.

  As illustrated in FIG. 2A, a water mass that moves due to waves, tidal currents, and the like flows in the movement direction x so as to be substantially orthogonal to the vertical portion 12 of the permeable structure 10 and passes through a large number of openings 13. Coral gravel 1 that has moved underwater with the movement of the water mass is captured by a large number of openings 13, and as shown in FIG. 2 (b), the captured coral gravel 1 begins to accumulate on the bottom plate portion 11 and its surroundings, Due to the permeability of the accumulated coral gravel until a certain deposition thickness, the water mass continues to act on the numerous openings 13, and the coral gravel 1 continues to move with the water mass and is captured and deposited on the numerous openings 13. to continue.

  As shown in FIG. 2 (c), when the deposit thickness of the coral gravel 1 increases, the coral gravel 1 becomes the coral gravel deposit 2, and its permeability decreases, the coral gravel deposit 2 becomes a new bottom ground. Thus, the height at which the water mass flows is higher than the upper surface of the coral gravel deposit 2. As a result, the coral gravel 1 is sequentially deposited at a higher position, and the upper surface of the coral gravel deposit 2 is raised.

  As shown in FIG. 2 (d), as the coral gravel deposit 1 progresses, the upper surface of the coral gravel deposit 2 gradually increases, and the lower part of the coral gravel deposit 2 becomes wider and the foreshore slope becomes narrower at the upper part. For this reason, when the moving direction of the water mass gradually changes to the diagonally upward direction x ′, while the top of the permeable structure 10 is at a position higher than the surface of the water, the coral gravel 1 As a result, the top surface of the coral gravel deposit 2 is exposed from the water surface.

  That is, the coral gravel deposit 2 can be deposited up to the surface of the water while forming a foreshore gradient in which the offshore coastal sedimentation and erosion occur due to waves. It is known that the foreshore slope is gentle on normal sandy beaches when the waves are high, and the foreshore slope becomes steep when it is calm. In other words, the coastal topography shifts to a more stable shape according to the characteristics of the incoming wave. The slope of the coast off the coast at this time is called the foreshore slope. The foreshore slope also varies depending on the grain shape of the sediment.

  As described above, according to the present embodiment, the land can be landed by capturing and depositing the coral gravel 1 that moves in the water together with the water mass in the region where the permeable structure 10 is installed. That is, only by installing the permeable structure 10, by utilizing natural external force, land formation by the coral gravel 1 is promoted, and the remote island can be preserved.

  In addition, 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 edge of the transmissive structure 10 is higher than the water surface. By being at a high position, coral gravel is launched and deposited up to the surface of the water, making it easier to realize land formation by coral gravel deposition.

  Further, the deposition when the top end height of the permeable 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 shows processes (a) to (e) in which coral gravel is captured and deposited when the top height of the permeable structure 10 is lower than the water surface height. Show.

  As shown in FIGS. 10 (a) to 10 (d), the coral gravel 1 is initially deposited on the front surface of the permeable structure 10 as in FIGS. 2 (a) to 2 (c). After the top surface of the coral gravel deposit 2 reaches the top 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 formed on the back surface, and thereafter, the coral gravel 1 proceeds on the back side of the permeable structure 10 as shown in FIG. In this way, land formation due to the accumulation of coral gravel 1 becomes easier to realize.

  In the case of FIG. 2 as well, the coral gravel 1 continues to accumulate after the top surface of the coral gravel deposit 2 reaches the top of the permeable structure 10 as shown in FIG. e) Coral gravel 1 progresses on the back side of the permeable structure 10 as in (f).

  The effect of this embodiment is further demonstrated. If an impermeable structure is installed instead of the permeable structure as shown in FIG. 1, the periphery of the impermeable structure will be scoured, which is completely opposite to the deposition and the opposite result. It becomes.

  In addition, when sand is used, since the particle size is small, the opening of the permeable structure that captures the sand becomes small, thereby inhibiting the movement of the water mass. As a result, a phenomenon similar to the case where the impermeable structure is installed occurs, and sand does not accumulate on the front surface of the permeable structure targeted for sand, and the accumulation effect as in this embodiment is achieved. 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 permeable structure according to another first example of the present embodiment. FIG. 12 is a perspective view showing a basic configuration of a permeable structure according to another second example of the present embodiment.

  As shown in FIG. 11, the transparent structure 16 omits the bottom plate portion 11 of FIG. 1, and is provided with support members 14 and 14 so as to protrude perpendicularly to the vertical portion 12 at the lower ends of both ends of the vertical portion 12. It is a thing. The vertical portion 12 is supported at lower ends of both ends by support members 14 and 14 extending in the front and rear directions of the vertical portion 12. In addition, the permeable structure 16 is fixed to the bottom of the water by fixing members (not shown) such as anchors by the support members 14 and 14.

  As shown in FIG. 12, the permeable structure 17 omits the bottom plate portion 11 of FIG. 1, places the vertical piles 15, 15 on the water bottom at the installation position, and places the vertical portion 12 at both ends of the vertical piles 15, 15. It is fixed to and supported by. In the example of FIG. 12, a fixing means such as an anchor is not necessary.

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

  3 (a) and 3 (b) has the same configuration as that of FIG. 1, except that a plurality of vertical portions 21, 22, 23, 24 are provided on the bottom plate portion 25 at predetermined intervals. To do. Each of the vertical portions 21, 22, 23, and 24 is configured so that the height of the top end is reduced in this order, and each of the vertical portions 21, 22, 23, and 24 has a large number of openings as in FIG.

  As shown in FIG. 3A, when the normal movement of the water mass is the movement direction x, the permeable structure 20 is arranged with the vertical portion 24 having a low top end height upstream of the movement direction x. The vertical portions 23, 22, and 21 having a high top end height are arranged in order toward the downstream side in the movement direction x.

  Here, the problem when the permeable structure 10 of FIG. 1 is installed alone will be described. If the movement direction x of the water mass is uniform as shown in FIG. 4A, the deposition of the coral gravel 1 is promoted. However, as shown in FIG. 4 (b), when the movement direction of the water mass becomes the reverse direction ax depending on the period, the movement of the water mass may destroy the coral gravel accumulated so far. is there.

  With respect to the above problem, according to the present embodiment, a plurality of vertical portions 24, 23, 22, and 21 are lowered in the height at the upstream side in the movement direction x of the water mass, and downstream in the movement direction x. As shown in FIG. 3B, even if the movement of the water mass is in the reverse direction ax with respect to the movement direction x, the plurality of vertical portions 21 to 21 are arranged. It is possible to capture and deposit coral gravel in each of the adjacent spaces 24, and to prevent the coral gravel that has accumulated due to the movement of the water mass in the moving direction x from moving and being destroyed.

  FIG. 5 is a side view schematically showing a structure according to another example of the present embodiment. The structure 30 in FIG. 5 is composed of a plurality of permeable structures 10A, 10B, 10C, and 10D, and the plurality of permeable structures 10A to 10D are arranged on the bottom of the water in the movement direction x of the water mass. Each of the permeable structures 10A to 10D has the same basic configuration as that of the permeable structure 10 in FIG. 1, but their vertical portions 12a, 12b, 12c, and 12d are configured so that their top end heights are sequentially lower. Each has a large number of openings as in FIG.

  According to the structure 30 of FIG. 5, each of the permeable structures 10 </ b> A to 10 </ b> D is configured so that the top end heights of the vertical portions 12 a, 12 b, 12 c, and 12 d are sequentially decreased from the downstream side with respect to the movement direction x of the water mass. 3 (a) and 3 (b) can obtain the same effect as the permeable structure 20 having a plurality of vertical portions, and the movement of the water mass is in the direction opposite to the movement direction x. Even when the vertical portions 12a to 12d of the plurality of permeable structures 10A to 10D are adjacent to each other, the coral gravel can be captured and deposited in the adjacent spaces, and the water mass moves in the movement direction x. It is possible to prevent the accumulated coral gravel from moving and being destroyed.

  3 and 5, the interval between the vertical portions of the permeable structure is preferably set as appropriate so that the accumulation of coral gravel and the prevention of the destruction of the accumulated 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 shown in FIG. 6 includes a plurality of permeable structures 10, and the plurality of permeable structures 10 are arranged in a row in the horizontal direction so as to be orthogonal to the water bottom movement direction x. Is. Each permeable structure 10 has the same configuration as in FIG. 1, and each vertical portion 12 has a number of openings 13. According to the structure 40 of FIG. 6, the coral gravel can be expected to be captured and deposited in a wide range by arranging the plurality of permeable structures 10 in a row in the lateral direction.

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

  The structure 50 of FIG. 7 arranges each row | line | column ac of several permeable structure 10A-10C in the moving direction x of a water mass. The permeable structures 10A to 10C in each row a to c are installed so that the top end heights of the vertical portions 12a, 12b, and 12c are sequentially decreased from the downstream side with respect to the movement direction x of the water mass.

  Since the structure 40 of FIG. 6 only has a plurality of permeable structures 10 arranged in a row in the lateral direction, when the moving direction of the water mass changes in the opposite direction depending on the time, the structure shown in FIGS. However, according to the structure 50 in FIG. 7, the same effect as in FIGS. 3 and 5 can be obtained, and the movement of the water mass is the moving direction. Even if the direction is opposite to x, coral gravel can be captured and deposited in each space where the vertical portions 12a to 12c of the rows a to c are adjacent to each other, and the water mass moves in the movement direction x. Thus, it is possible to prevent the coral gravel deposited and destroyed from moving. As a result, even when the direction of movement of the water mass changes in the opposite direction depending on the time, coral gravel can be expected to be captured and deposited 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. In the structure 70 of FIG. 13, a plurality of permeable structures 17 using the vertical piles 15 of FIG. 12 are arranged in a row in the horizontal direction so as to be orthogonal to the water mass moving direction x on the bottom of the water, as in FIG. It was installed side by side. In the structure 70, adjacent vertical portions 12 are fixed and supported by a common vertical pile 15. According to the structure 70, there exists an effect similar to FIG. Also, the structure 70 of FIG. 13 is arranged in the same manner as in FIG. 7, and the same effect as 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 the top view (a) which shows the structure by 4th Embodiment roughly, and the figure (b) seen by cut | disconnecting in the VIIIB-VIIIB line direction. FIG. 9 is a schematic plan view for explaining the operational effects of the present embodiment.

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

  The basic structures of the permeable structures 61A to 63A are the same as those of the permeable structure 10 in FIG. 1, but their vertical portions 61a, 62a, and 63a are at their top ends as shown in FIG. 8B. The height decreases from the inside toward the outside. Each vertical part 61a-63a has many opening similarly to FIG.

  According to the structure 60 in FIG. 8, the water depth is locally shallow at the periphery accumulated by the coral gravel, so that the wave from the moving direction x is refracted and concentrated behind it as shown in FIG. As a result, the coral gravel moves from the left and right on the back surface 65 of the structure 60, and the coral gravel deposition is further promoted in the region N formed on the back surface 65 side by the concentration of the waves. As a result, land reclamation by coral gravel capture and accumulation is efficiently performed. In addition, the coral gravel is efficiently captured and deposited by installing the structure 60 at a point where the moving direction of water mass such as waves and tidal currents changes depending on the period and acts from a plurality of directions.

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

  As described above, the modes for carrying out the present invention have been described. However, the present invention is not limited to these, and various modifications can be made within the scope of the technical idea of the present invention. For example, a plurality of the permeable structures 10 and 20 shown in FIGS. 1 and 3 of the present embodiment can be installed in succession, but such installation may be performed not only at one location but also at a plurality of locations separated 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 separated 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 columns in FIG. 7 are not limited to the illustrated numbers, but can be increased or decreased as necessary. is there. Moreover, the number of the permeable structures arranged in a line in the horizontal direction in FIGS. 6 and 7 can also be increased or decreased as necessary.

  Moreover, in FIG.1, FIG.11, FIG.12, although the perpendicular | vertical part 12 which is a capture part which has the some opening 13 is comprised by flat form, this invention is not limited to this, What is necessary is just planar shape, Examples of the planar capturing portion include not only a flat plate-shaped one and a flat surface entirely, but also a one that is configured in advance such as a V shape or a wave shape.

  In addition, when the capturing part is made of, for example, a flat plate made of a steel material or expanded metal, it has a certain degree of rigidity, so that it remains almost flat during service. If the material is made of a flexible material in a planar shape, it may be deformed into a curved shape due to the movement of the water mass during service.

  FIG. 14 shows a structure 80 in which a plurality of permeable structures 18 each having a capturing portion 12 ′ having a plurality of openings 13 provided on the bottom plate portion 11 are arranged in a row in the horizontal direction as in FIG. 6. Further, in FIG. 15, a plurality of vertical piles 15 are placed on the bottom of the water, and a plurality of permeable structures 19 in which the trapping portions 12 ′ are fixed and supported by the vertical piles 15 are arranged in a row in the horizontal direction as in FIG. 6. The structures 90 arranged in the order shown in FIG. 14 and 15 is made of a flexible material such as a resin material or a wire mesh, and is flat when installed and is erected in the vertical direction. The movement of the lump may be deformed in the moving direction x and bend in a concave shape.

  Moreover, although the vertical part 12 of FIG.1, FIG.11, FIG.12 and also the capture | acquisition part 12 'of FIG.14, FIG.15 are standingly arranged in the perpendicular direction, this invention is not limited to this, It may be tilted back and forth with respect to the moving direction. That is, in the present invention, the entire planar capturing portion having a plurality of openings may be inclined with respect to the vertical direction.

  Moreover, the coral gravel of this specification originates from a coral reef, and has many shapes like a tree branch or a table shape.

  According to the present invention, it is possible to provide a method for depositing coral gravel to land, and a permeable structure and a structure that can be used therefor, so that a new island can be created.

DESCRIPTION OF SYMBOLS 1 Coral gravel 2 Coral gravel deposit 10, 16, 17, 18, 19, 20 Transparent structure 10A, 10B, 10C, 10D Transparent structure 11 Bottom plate part 12 Vertical part (capturing part)
12 'capture part 12a, 12b, 12c, 12d vertical part (capture part)
13 opening 21, 22, 23, 24 vertical part (capturing part)
25 Bottom plate portion 30, 40, 50, 60, 70, 80, 90 Structures a to c One row G Water bottom M One plane region x Movement direction
ax reverse direction

Claims (7)

A method of depositing coral gravel and landing it,
A permeable structure having a plurality of openings capable of capturing coral gravel is installed in a direction in which a water mass can pass,
A land-based method by coral gravel deposition in which the coral gravel is deposited by passing the water mass through the opening of the permeable structure and capturing the coral gravel.   2. The land by coral gravel deposition according to claim 1, wherein the permeable structure includes a planar capturing portion having the opening, and the capturing portion is installed so as to be substantially orthogonal to a moving direction of the water mass. Method. Collect coral gravel that exists around the planned installation position of the permeable structure,
Measure the long dimension and short dimension of the collected coral gravel,
An average dimension is calculated from the measurement result,
The landing method by coral gravel deposition according to claim 1 or 2, wherein the size of the opening is set based on the average dimension. A permeable structure to deposit and land coral gravel,
It has multiple openings that can capture coral gravel,
A permeable structure for passing the water mass through the opening and capturing the coral gravel by being installed in a direction in which the water mass can pass.   The permeable structure of Claim 4 provided with the planar acquisition part which has the said opening.   6. The permeable structure according to claim 4, wherein a size of the opening is equal to or less than a long dimension and a short dimension of an average dimension of the coral gravel. A structure for depositing coral gravel and landing it,
A structure comprising a plurality of the permeable structures according to any one of claims 4 to 6.

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