JPH0562164B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a seawall block and a method for constructing a seawall using the same.

(Prior art and its problems) Conventionally, so-called three-sided seawalls and back seawalls have been lined with the front, top, and rear surfaces 1, 2, and 3 shown in Figure 1 a and b, as seawalls to prevent storm surges in shallow bays or inland seas. A typical example is a sloped type seawall that uses only the top layer 1 of a three-sided seawall with a high ground.
These are intended to protect the hinterland 5 of the seawall 4 by directly blocking the waves running upstream, but recently they have begun to be used as seawalls on coasts facing the open sea that are not attacked by high waves. Ivy.

However, if such a seawall is adopted on a coast that is not attacked by high waves, the sandy beach in front of the seawall, so-called foreshore 6, will gradually disappear due to the waves, and the accompanying increase in reflected waves will cause erosion. Proceed rapidly. This may lead to the complete disappearance of the foreshore, which may eventually lead to the collapse of the seawall.

Therefore, research was conducted, and a so-called block gently sloping seawall was developed, which takes into consideration the landscape and use of the coast, while also protecting the foreshore and sedimentation by gently receiving waves. As shown in FIG. 2a, this uses a drum-shaped block 7 with a constricted center and provided with a through-water collection hole 7a. For example, first
They are stacked so that the constricted portions 7b are located in the left-right direction as shown in Figure b. Next, the block row 8a is stacked so that the wide portions 7c of two blocks are located in the left and right constrictions 7b of the block row 8a.
Make b and 8c. Then, in this manner, block rows 8d, 8e, etc. are created in the left and right direction, and the second
The seawall 9 is constructed as shown in Figure c, and is intended to preserve the foreshore 6 based on the following principle.

That is, in this method, sand is carried onto the seawall in a laminar and floating state by waves running upstream in front of the seawall as a water current, and a part of the sand is captured in the water collection hole 7a. A part of the water flow when the waves return on the seawall surface is allowed to permeate inward of the seawall through the water collection hole 7a, thereby reducing the amount of water flowing down the front of the seawall. Sedimentation and capture. The water based on the permeation effect of the water collection hole 7a is made to flow out from the water collection hole 7a together with the sand later than the water directly flowing down the seawall until the next wave arrives. As a result, sediment is deposited on the front of the lower part of the seawall, and furthermore, the shoreline is moved forward by the sediment, thereby preserving the foreshore.

However, in this seawall, the blocks are interconnected only in the vertical and horizontal directions of the seawall, as shown by the arrows in Figure 2b.
In other words, the connection in the front and rear directions of the seawall cannot be maintained.
For this reason, it is easy to be washed away by the force of waves, for example 2 to 3
If any of the pieces leak out, there is a risk that the entire revetment will collapse and be destroyed.

In addition, as mentioned above, the sedimentation of sand at the lower part of the front of the seawall is largely related to the water collection holes, whose size depends on the grain size of the sand,
It is necessary to select according to the degree of slope in front of the seawall. Therefore, if the construction points are different, it is necessary to create blocks with water collection holes that meet the conditions of each installation point, but this is disadvantageous from an economical point of view, as it hinders mass productivity. Furthermore, in this method, as shown in Fig. 2b, since the water collection holes 7a are arranged in a single vertical line with intervals, the sand carried onto the seawall blocks is transported along the line where the water collection holes 7a are arranged. is captured, but capture is not performed between the water collection holes 7a. Therefore, the disadvantage is that the effect of sedimentation is small and the effect of preserving the foreshore is small.

(Object of the invention) The present invention uses blocks of the same size to adjust the size within the required range, for example, with a porosity of 20 to 30.
% variable porosity and a staggered arrangement of water collecting holes can be freely created, and a method for constructing a seawall using this block.The foreshore and hinterland of the seawall can be conserved economically and reliably. It was designed so that it could be done.

Next, the present invention will be explained in detail using the drawings.

(Means of the present invention for solving the problems) As shown in the perspective view of the embodiment shown in FIG. , a block having a downward hook-shaped joint 11 and an upward hook-shaped joint 12 to which the upward and downward hook-shaped joints 12 and 11 of the mating block are mated is made, and a large number of blocks are combined in a staggered arrangement. This involves constructing a seawall with water collection holes.

That is, the block of the present invention has coupling protrusions 11a located on the transverse surface side, which are formed by cutting out both transverse corners of one side of the rectangular parallelepiped 10 from one surface in the thickness direction to the other surface, so that the back is coupled. 2 which becomes the recessed part 11b
An upward hook-shaped joint having two downward hook-shaped joints 11, a joint protrusion 12a of the same shape formed by notching the other lateral corner in the opposite direction to the downward hook-shaped joint 11, and a rear joint recess 12b. A section will be established. Further, the downward and upward hook-shaped coupling parts 11 and 12 are arranged to have the same size so that the coupling protrusions 11a and 12a of the downward and upward hook-shaped coupling parts 11 and 12 fit and fit into the respective coupling recesses 12b and 11b. It is characterized by being isomorphic. A seawall is constructed by combining and connecting a large number of blocks of the same shape according to the following procedure. In addition, in FIG. 3, 11c and 12c are connecting protrusions 11a and 1
This guide slope is provided to make it easier for the guide 2a to fall into the coupling recesses 11b and 12b, and may be omitted.

As shown in FIG. 4a, the block is first
are placed at the bottom of the earth embankment surface of the seawall at intervals. Then, the coupling protrusions 11a of both downward hook-shaped coupling parts 11 of the block are dropped into the coupling recesses 12b of both upward hook-shaped coupling parts 12, and the blocks are coupled. Next, the coupling recesses 1 of both upward hook-shaped coupling parts 12 of the block facing the front side.
The connecting protrusions 11a of both downward hook-shaped connecting parts 11 of the blocks 2b are dropped into the blocks 2b, and the blocks are connected.Then, the blocks are connected in the same manner as shown in FIG. 4b. form. Finally, the 4th block remaining on the four circumferential surfaces of the block surface, that is, the left and right and top and bottom directions of the block surface.
The missing parts 13 and 14 in FIG. b are filled in, for example, in the following manner. In other words, fill it with concrete or
The filling block 15 for the left and right directions shown in FIG. and upward and downward joint parts 1
2 and 11 for filling, and a filling block 16 for the vertical direction shown in FIG.
As shown in FIG. 4c, the block with the rectangular water collecting hole 17 is formed by turning it upside down and fitting it into the downward and upward hook-shaped joints 11 and 12 of the block. Complete the upholstery.

(Operations and Effects of the Invention) As described above, in the block of the present invention, there are spaces a and b between the connecting portions 11 and 12 provided at the four corners, respectively, as shown in FIG. 3a. Therefore, when the blocks are connected without creating a gap between each block, the distance a between the downward hook-shaped joint 11 and the upward hook-shaped joint 12 is defined as the length in the vertical direction, as shown in FIG. A water collection hole 17 whose lateral length is the distance b between the hook-shaped joints (or between upward hook-shaped joints) 11 is automatically formed as the block is assembled. Moreover, the horizontal length of this water collection hole 17 is
As shown in Fig. 4b, the blocks are not connected without creating a gap between them, but are connected in the direction of the arrow in Fig. 4b, that is, by shifting the blocks in the left-right direction, thereby forming downward and upward hook-shaped joints. 11 and 12 in the width direction, that is, the length in the left-right direction. Therefore, by using the same block, water collection holes 17 of different sizes can be formed to accommodate changes in the slope of the seawall and the grain size of the sand.
It is therefore possible to economically construct a seawall that meets the economic requirements, and the drawbacks of conventional blocks are eliminated. At this time, the gaps formed between the blocks may be left as they are or, if necessary, filled with rubble to make them flat.

In addition, the connections between the blocks in the present invention are not limited to the vertical and horizontal directions as in conventional blocks, but also, as shown in FIG. Just as it is being held down from the front by both corners, both upper corners of each block are all held down by both lower corners of the other block, and the connection is maintained in the front-rear direction. Therefore, it is possible to reliably prevent the blocks from falling off and flowing out due to the force of the waves.
It is possible to construct a more solid revetment compared to conventional blocks.

Further, the water collection holes 17 of the present invention are automatically arranged in a staggered manner as shown in FIG. 4c. Therefore, compared to the conventional block-based revetment described above in Figure 2, the width between adjacent water collection holes is smaller, so sand is captured better, the sedimentation function is improved, and the foreshore conservation effect is improved. It has the advantage of being able to achieve That is, as described above, the sedimentation function of the present invention removes a part of the sand carried in the bed sweep state and floating state B by the running water A when the wave W runs up as shown in Fig. 5a. Water flow A
The function of the water collection hole 17 is to capture C sequentially from bottom to top according to the upward flow, and when the wave W returns as shown in Fig. 5b, the water D flowing down on the surface of the seawall 18 is made to permeate E. At the same time, the action of the water collection hole 17 that sediments and captures the sand in the flowing water D sequentially from top to bottom as the flowing water flows downward, and the permeable water E is transferred from the flowing water D flowing down on the surface of the seawall 18. By repeating the action of the water collection hole 17, which gradually flows down with the sand as a small water flow F, the sand is deposited from the lower water collection hole to the upper water collection hole, thereby creating a seawall. It is deposited over the entire front surface and advances the shoreline. Therefore, by arranging the water collecting holes 17 in a staggered manner as in the present invention,
This is almost the same as creating a row of blocks having water collection holes between the rows of blocks having water collection holes as described above, and the sand trapping effect can be improved by reducing the amount of water flowing down without trapping the sand.

Next, the sedimentation function according to the present invention will be explained with reference to the experimental results shown in FIGS. 6 and 7. Figure 6a,
The results of b and c are as follows: Sand with a median grain size of 0.27 mm was poured into a wave channel with a length of 77 m, a width of 0.9 m, and a height of 1.2 m to create a seabed slope of 1/15, and the water depth was 80 cm. Wave height 30cm,
Waves with a period of 2 seconds are applied for 2 hours, 4 hours, and 8 hours (equivalent to a local equivalent water depth of 16 m, wave height of 6 m, and a period of 9 seconds, 9 hours, and 18 hours). Showing changes in the topography of natural beaches,
The solid line shows the topographical change when the embankment of the present invention was installed, and the dashed-dotted line shows the initial slope. As is clear from this, when there is no seawall, as the wave action time elapses, the shoreline gradually changes as shown in a, b, and c in Figure 6, which show the state after 2 hours, 4 hours, and 8 hours of wave action. The amount of erosion is gradually increasing as the area gradually retreats. On the other hand, the horizontal length is 6 cm, the vertical length is 9 cm, and the thickness is 3 cm.
cm, weight 350g (local equivalent: 1.2m, 1.8m, 0.6m,
When a revetment with a legal slope of 1/3 is installed near the shoreline using a block of the present invention (equivalent to 2.8 tons), the vicinity of the shoreline will be protected by the revetment as shown by the solid curve, and the sedimentation function of the present invention will also be improved. It can be seen that sedimentation 19 is carried out in front of the seawall 18 and the shoreline moves forward.

Furthermore, Fig. 7 is a diagram showing the classification of two-dimensional topographic changes and the hydraulic conditions for determining erosion and sedimentation, which have been tested by many researchers. In the figure, the type represents sedimentary landform, the type represents erosional landform, and the type represents landform intermediate between them, and the boundary values are C=8 and C=4. In the figure, tanβ is the slope of the seawall, d is the median grain size of the sand, Lo is the wave wavelength, and Ho is the height of the seawall. When the classification of topographical changes obtained from the experiment in Figure 6 is plotted on this figure, it can be seen that the present invention It can be seen that when a seawall is implemented, the sedimentation tendency shifts in both cases (when a seawall is installed on the shoreline) and (when a seawall is installed on land), as shown by the solid line in the figure. In other words, the erosion area used to be expressed as C=4, but with the construction of the seawall, the hydraulic conditions for the sedimentation process have been expanded, and the foreshore can be protected against high waves that would cause erosion under natural conditions. can be held.
For example, when a natural beach is exposed to waves with a wave height of 30 cm and a period of 2 seconds, it will be eroded, but if a seawall according to the present invention is installed, no erosion will occur and the foreshore will be stabilized.

[Brief explanation of the drawing]

Figures 1a and b are cross-sectional views showing typical examples of conventional seawalls, Figures 2a, b, and c are perspective views of conventional blocks, an explanatory diagram of the construction method, and a construction example diagram, and Figure 3
Figure a is a perspective view of an embodiment of the block of the present invention, figure b,
Fig. 4c is a perspective view of an embodiment of a horizontal filling block and a vertical filling block, Fig. 4a is an exploded perspective view for explaining a method of constructing a seawall using blocks of the present invention, Fig. 4b and c are perspective views of an example of construction, respectively. FIGS. 5a and 5b are explanatory diagrams of the sedimentation action during the run-up and return of waves, respectively, and FIGS. 6 and 7 are experimental examples showing the sedimentation function of the seawall of the present invention. 1, 2, 3... Seawall lining surface, 4... Seawall, 5...
... hinterland, 6... foreshore, 7... conventional block, 7
a...Water collection hole, 7b...Neck part, 7c...Wide part, 8a, 8b, 8c, 8d, 8e...Block row, 9...Conventional block-clad revetment,...
...Block of the present invention, 10... Rectangular parallelepiped, 11... Downward hook-shaped connecting portion, 11a... Connecting protrusion, 11b...
...Joining recess, 12...Upward hook-shaped joining section, 12a
...Joining protrusion, 12b...Joining recess, 13...Left-right missing part, 14...Upper-down missing part, 15...
...Filled blocks for left and right directions, 16...Filled blocks for vertical directions, 17...Water collection hole of the present invention, 18...
Seawall of the present invention, 19...Sediment, A...Running water when waves run up, B...Suspended state of sand, C...Sand capture, D
...Running water falling on the surface of the seawall, E...Water penetration, F...
...Flowing water with a smaller flow D, G...Water collection hole spacing.

Claims (1)

[Scope of Claims] 1. A downward hook-shaped joint consisting of a joint protrusion formed by cutting out two corners of one lateral corner of a rectangular parallelepiped from one surface in the thickness direction to the other surface, and a joint concave portion behind the joint protrusion. and an upward hook-shaped joint portion, which is formed by cutting out two corners of the other side in the horizontal direction from the surface opposite to the downward hook-shaped joint portion, and a joint protrusion and a joint recess provided behind the joint protrusion. At the same time, the downward and upward hook-shaped joints have the same shape so that the respective joint protrusions can fit and fit into the respective joint recesses, and the porosity can be varied by using the same block by adjusting the joint area of both. A seawall block that is characterized by being able to 2. A downward hook-shaped joint consisting of a joint protrusion and a joint concave portion behind the joint protrusion, which are cut out from two corners of one lateral corner of a rectangular parallelepiped from one side in the thickness direction to the other side, and the other side in the lateral direction. is provided with an upward hook-shaped joint portion consisting of a joint protrusion cut out from the opposite side of the downward hook-shaped joint portion at both corners thereof and a joint concave portion provided behind the joint protrusion, and the downward hook-shaped joint portion The first and second revetment blocks, each having an upward hook-shaped joint having the same shape that allows the respective joint protrusions to fit and fit into the respective joint recesses, are arranged laterally, and the upward hook-shaped joints are opposed to each other. In between, the downward hook-shaped joints on both sides of the third revetment block are combined and connected, and the opposing downward hook-shaped joints of the fourth and fifth revetment blocks are connected to the upward hook-shaped joints on both sides of the third revetment block. 1. A method for constructing a seawall, which comprises sequentially joining blocks together in a planar manner to form a block-covered surface having water collection holes arranged in a staggered manner.