JP2008255576A - River bed forming block, river bed structure using the block, and river bed forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a river bed forming block which can prevent scouring caused by a water flow, by enhancing shape retentivity of a formed artificial river bed, and which can alleviate an erosive action on a river bank by guiding a channel for river water in a desired direction by a flow guiding body. <P>SOLUTION: Characteristically, this river bed forming block 1f, which is arranged to act on a flow of river water on the river bed, comprises: a rod-like flow guiding portion 2d which is formed in a linear, curved or bent shape; at least one shaft portion 3 which is fixed to the flow guiding portion 2d; and at least one leg portion 4 which is provided in a circumferentially protruded manner near the end, on the side of the nonprovision of the flow guiding portion 2d, of the shaft portion 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an artificial riverbed formed on a riverbed, and relates to a riverbed forming block for preventing scouring of a riverbed by a water flow, a structure of a riverbed using the same, and a method of forming the same.

Japan, which is an island country, has a steep terrain, so rainwater suddenly flows into the river when it rains and the amount of water increases. Has occurred.
For the purpose of preventing such flood damage, the riverbank and riverbed were made of concrete to give resistance to erosion and scouring by water flow. Precious ecosystems such as fish, insects, and plants are lost, and it is desired to protect both ecosystems and flood control in rivers.
In ancient Japan, the river bed flow was slowed down by installing a “sink”, a riverbed protection structure formed by weaving branches of trees, on the riverbed.
The gaps between the structures made up of the tree branches that make up the subsidence also serve as a habitat for aquatic organisms, and can also be expected to protect river ecosystems.
On the other hand, sinking is made by weaving a branch of a tree, so it is difficult to mass-produce industrially, and when the amount of water in the river increases significantly, the sinking itself will be washed away, and a new one will be created each time. It was necessary to create a sink and install it on the river bed. In addition, since the sinking is made using a natural material, it deteriorates and damages as time passes, so that it is necessary to perform maintenance periodically, and there is a problem that costs are increased.
In order to deal with such problems, several techniques for preventing scouring of a riverbed by providing a structure on the riverbed and controlling the flow of water have been disclosed.

For example, Patent Document 1 discloses an invention relating to a flow guide wall installed on a river bed under the name “flow guide wall” in order to control the flow path of river water.
In the invention described in Patent Document 1, a flow guide plate having sliding grooves on both left and right ends is slidably loosely fitted to a column, and the downstream side of the flow guide plate is supported by an oblique column. Is configured to be slidable up and down along the column.
By installing multiple flow guide walls with the above configuration in the curved river basin, it is possible to prevent the water flow from flowing toward the levee in the curved basin when the river increases, and to prevent the breakage of the levee due to muddy flow it can.
In addition, sediment accumulation is suppressed inside the curved basin, and river damage due to flooding is reduced.
Also, under circumstances where the water is increased and immersed in the muddy flow to the vicinity of the bridge girder, by using the bridge pier formed in the shape of the flow guide wall of the present invention, the flowing water bends in the tangential direction of the curved flow and becomes an outer bank of the river, etc. This has the effect of reducing such destructive water pressure.

In addition, in Patent Document 2, the name of “river flow control method and apparatus”, in the vicinity of the downstream of the river facing the sea, sediment flowing down from the upstream of the river settles and accumulates on the bottom of the water, An invention relating to a method and an apparatus for preventing the formation of a Nakasu and the phenomenon of blocking an estuary has been disclosed.
In the invention according to Patent Document 2, a plurality of sets of inverted cross-shaped water bodies are arranged along the flow on the river bed near the river mouth, and there is a gap between the water body and the riverbank. It is characterized by providing.
According to the invention according to Patent Document 2 configured as described above, there is an effect that it is possible to prevent the formation of a Nakasu or the clogging of the estuary by the earth and sand flowing down from the upstream near the estuary of the river.
Moreover, it has the effect that the sediment flowing down from the upstream can be swept away from the estuary to the offshore by the high flow velocity of the central part of the river.
In addition, by providing a gap between the reverse C-shaped water system installed in the center of the river and the riverbank, the flow in the gap part will flow backward or stagnate, so that It can make the top easier and at the same time have a positive effect on the riverbank.

JP 2001-248132 A JP-A-9-275939

However, since the flow guide wall according to Patent Document 1 which is the above-described prior art is installed on the riverbed, the flow guide wall itself is damaged or washed away by water pressure when the amount of water in the river increases significantly. There is a problem that a constant rectifying effect cannot be expected over a long period of time.
In addition, the invention according to Patent Document 1 is not configured to improve the shape retention of the riverbed itself, and therefore does not provide a riverbed that is difficult to be scoured by water flow.

Further, in the invention described in Patent Document 2, it is considered that scouring by a water flow proceeds in the vicinity of the center of the river. If this state is left unattended, the river bed on which the water control body is placed is gradually eroded. Eventually, the water body could fall over the riverbed.
That is, the invention described in Patent Document 2 is not configured to enhance the shape retention of the riverbed itself, and therefore does not provide a riverbed that is difficult to be scoured by a water flow.

  The present invention has been made in response to such a conventional situation, and the riverbed itself is reinforced to prevent scouring of the riverbed by the water flow, and at the same time to reduce the flow velocity of the river water by disturbing the water flow on the surface of the riverbed. An object of the present invention is to provide a riverbed forming block capable of preventing damage to the riverbank due to water pressure by preventing the flow of water toward the riverbank, a structure of the riverbed using the same, and a method of forming the same .

In order to achieve the above object, the river bed forming block according to the invention of claim 1 is a river bed forming block arranged to act on the flow of river water in the river bed, which is rod-shaped and linear or A curved or bent flow guide portion, at least one shaft portion fixed to the flow guide portion, and at least a protruding portion in the circumferential direction in the vicinity of the end portion of the shaft portion where the flow guide portion is not provided. And a single leg portion.
In the invention with the above-described configuration, the flow guide portion projects from the river bed into the water and has an effect of disturbing the water flow in the vicinity of the river bed. In addition, the shaft part is accommodated in the ground of the river bed and supports the flow guide part, so that even when the flow of river water acts on the flow conductor, it prevents the flow guide part from detaching from the river bed or being displaced. Has an effect. Furthermore, the leg portion has the effect of preventing the flow conductor from being detached or misaligned in cooperation with the shaft portion while allowing the riverbed forming block according to claim 1 to stand on the excavated riverbed.
Further, by using a plurality of riverbed forming blocks according to claim 1, a framework structure is formed on the riverbed, and this framework structure holds the riverbed forming material and has an effect of preventing movement due to water flow.
In particular, when the riverbed forming block according to claim 1 is embedded using an irregular natural stone that forms a gap when stacked, a gap is formed in the riverbed as a habitat for aquatic organisms. The gap is held in a stable state.

The river bed forming block according to claim 2 is the river bed forming block according to claim 1, wherein the shaft portion is suspended between the flow guide portion and the leg portion and in the circumferential direction of the shaft portion. Or it has at least 1 rod-shaped or flat plate-shaped branch part inclined.
In addition to the same operation as that of the first aspect of the invention, the invention having the above-described structure has a branch part, so that when the shaft part is accommodated in the ground of the river bed, the riverbed forming material and the riverbed according to claim 2 are provided. It has the effect of increasing the contact area with the forming block and increasing the detachment of the flow guide part from the river bed.
Moreover, when the said branch part is exposed to water from a river bed, it has the effect | action of disturbing a water flow by both a flow conductor and a branch part, and decelerating the flow velocity of river water.

The riverbed forming block according to the invention of claim 3 is a riverbed forming block arranged to act on the flow of river water in the riverbed, and has a rod-like shape and one curved or bent flow guiding portion. , At least one shaft portion fixed to the flow guide portion, at least one leg portion protruding in the circumferential direction in the vicinity of the end portion of the shaft portion where the flow guide portion is not provided, and the shaft portion One rod-like or flat plate-like branch portion that is suspended or obliquely provided between the flow guide portion and the leg portion and in the circumferential direction of the shaft portion, and has two centers at both ends of the flow guide portion The axis and the central axis of the branch part are characterized in that the angle between the three central axes is formed at 120 ° when projected onto the same plane perpendicular to the axial part.
In addition to the same operation as that of the invention of the second aspect, the invention having the above-described structure has an operation of forming an integral frame structure composed of a substantially hexagonal lattice on the river bed by combining a plurality of river bed forming blocks.

A riverbed structure according to a fourth aspect of the present invention is a riverbed structure using a plurality of riverbed forming blocks according to any one of the first to third aspects, and is an end portion of a flow guide section. One of the central axes is arranged on the river bed in the downstream direction of the river and in the direction of blocking the water flow.
In addition to the actions of the respective inventions according to the first to third aspects of the invention, the river bed in the direction downstream of the river and in the direction of blocking the water flow, in addition to the action of each of the inventions according to claims 1 to 3 It has the effect of guiding the flow of river water in a specific direction.

A riverbed structure according to a fifth aspect of the present invention is the riverbed structure according to the fourth aspect, wherein the end portions of the flow guide portion are arranged in contact or overlapped with each other.
In addition to the same operation as that of the invention of the fourth aspect, the invention having the above-described configuration has the effect of promoting the water flow inducing property and the water flow decelerating effect.

A riverbed structure according to a sixth aspect of the present invention is a riverbed structure using a plurality of riverbed forming blocks according to the second or third aspect, wherein the flow guide portion and the branch portion are bare on the riverbed. It arrange | positions in the state made to come out, It is characterized by the above-mentioned.
In addition to the same action as that of the invention described in claim 2 or claim 3, the invention having the above structure has an action that the branch part further promotes disturbance of river water.

According to a seventh aspect of the present invention, there is provided a river bed forming method comprising: an excavation process for digging a river bed; and an arrangement in which the river bed formation block according to any one of claims 1 to 3 is arranged on the river bed after this process. And a burying step of burying the shaft portion in a state where the flow guide portion or the flow guide portion and the branch portion are exposed on the river bed after this step.
The invention having the above-described configuration is obtained by capturing the invention described in claims 4 to 6 as a method invention, and has the same action as each invention described in claims 4 to 6.

The river bed forming method according to claim 8 is the river bed forming method according to claim 7, wherein, in the embedding step, natural stone is used as the river bed forming material when the shaft portion is buried in the river bed. It is what.
In addition to the same action as that of the invention described in claim 7, the invention having the above-described structure has the action that a gap is constantly formed in the river bed by the irregular natural stone. Moreover, this gap | interval has the effect | action of providing a itch for an aquatic organism.

As described above, according to the river bed forming block of the first aspect of the present invention, the flow guide portion becomes effective against the water flow of the river and has an effect of reducing the flow velocity. At this time, since the flow guide portion is supported by the shaft portion accommodated in the ground of the river bed, there is an effect that the flow guide portion can be prevented from being detached or moved by the water pressure due to the water flow.
On the other hand, since the framework structure is formed on the river bed by the river bed forming block according to claim 1, it is possible to prevent the sand and stones that are the river bed forming material from moving or running away in the water flow. Have. As a result, there is an effect that it is possible to prevent scouring of the riverbed and to prevent a significant change in the shape of the riverbed.
Further, the leg portion acts as a resistor when the water pressure is applied to the flow guide portion in the ground of the river bed, and has an effect of preventing the shaft portion from coming off the river bed.
In addition, having the leg portion 4 has the effect of allowing the riverbed forming block to stand on the excavation surface when the riverbed forming block according to claim 1 is placed on the excavated riverbed.
Therefore, it is not necessary to provide a separate facility for supporting the river bed forming block when forming the river bed, and the work of forming the artificial river bed can be simplified.
In particular, when an irregular natural stone is used as the riverbed forming material, the load can prevent the riverbed forming block according to claim 1 from being washed away and moved, and at the same time, the natural stone can be added to the riverbed. Gaps that serve as a reservoir for aquatic organisms are formed, and the river ecosystem can be preserved.

The block for forming a riverbed according to claim 2 of the present invention has the same effect as that of the invention according to claim 1, and particularly when both of the branch part and the leg part are embedded in the ground of the river bed. The riverbed shape retention effect of the riverbed forming block described in 1 can be further enhanced.
In particular, when the shaft portion is embedded with the branch portion exposed to the water from the river bed, the disturbance effect of the water flow is increased, and the effect of reducing the flow velocity can be promoted.

The river bed forming block according to claim 3 of the present invention is composed of a substantially hexagonal lattice by combining the river bed forming blocks according to claim 3 in addition to the same effects as the invention according to claim 2. A unitary frame structure can be formed on the riverbed.
As a result, the resistance of the river bed to water pressure increases, and the shape retention effect of the river bed is further promoted.

According to the river bed structure of claim 4 of the present invention, in addition to the effects of the inventions of claims 1 to 3, the center axis of the end portion of the flow conductor is directed in a specific direction, and this By arranging such flow conductors regularly on a plurality of river beds, the flow of river water can be guided in a desired direction.
Therefore, for example, when the river bed structure according to claim 4 is formed in a river having a curved flow path, by directing the central axis of the end portion of the flow conductor toward the center side of the river and the downstream side of the flow, The water flow can be guided to the center side to prevent the water flow from heading to the river bank, or the central axis of the end of the flow conductor can be directed inside the river and downstream of the flow, so that the water flow is It is guided to the inside of the river and has the effect that the water flow can be prevented from moving toward the outer riverbank.
Therefore, when the amount of water increases, the embankment can be prevented from being damaged or broken. Moreover, it has the effect of providing an artificial riverbed that is not easily scoured by the stream of river water.

  The structure of the river bed according to claim 5 of the present invention has the effect of the invention according to claim 4 in addition to the effect of each of the inventions of claims 1 to 3, and the water conveyance part is continuously continuous. The effect is that it can be further promoted.

The structure of the river bed according to claim 6 of the present invention has a high flow velocity reduction effect because it can form a large number of protrusions that serve as water flow resistance on the river bed in addition to the same effect as that of the invention described in claim 3.
Particularly, by forming the river bed structure according to claim 6 at the landing point in the weir, the water pressure generated at the time of landing can be efficiently dispersed in the water, and scouring of this part can be prevented. Has the effect of being able to.
As a result, there is an effect that the vicinity of the weir can be scoured and the weir itself can be prevented from collapsing.

  The river bed forming method according to claim 7 of the present invention is obtained by capturing each invention according to claim 4 to claim 6 as a method invention, and each method according to claim 4 to claim 6. It has the same effect as the invention.

In addition to the same effect as that of the invention described in claim 7, the river bed forming method according to claim 8 of the present invention uses an unnatural natural stone as a river bed forming material, so that the river bed is suitable for aquatic life. Can be provided.
As a result, an artificial riverbed that is not easily damaged by water pressure when the amount of water increases is provided, and at the same time, the river ecosystem can be preserved.

  A riverbed forming block according to the best mode of the present invention, a riverbed structure using the same, and a method of forming the same will be described with reference to FIGS.

  The riverbed forming block according to the present invention is a structural material for forming an artificial riverbed.

First, the riverbed forming block according to the first and second embodiments will be described in detail with reference to FIGS. 1 and 2. (Especially corresponding to claims 1 and 4)
FIG. 1: (a) is a conceptual diagram of the river-bed formation block which concerns on Example 1 of this invention, (b) is a conceptual diagram of the river-bed formation block which concerns on Example 2. FIG.
As shown in FIG. 1 (a), a riverbed forming block 1a according to Example 1 of the present invention has a columnar shaft portion 3 connected to a substantially lower center of a rod-shaped flow conductor 2a. Three leg portions 4 are projected in the vicinity of the end portion on the side not connected to the flow conductor 2a and in the circumferential direction thereof.
In addition, in FIG. 1A, the case where the leg portion 4 is suspended from the shaft portion 3 is described as an example, but the leg portion 4 is excavated from a position higher than the illustrated position. It may project toward the surface 6.
Thus, in the riverbed forming block 1a according to the first embodiment, the leg portion 4 is provided on the shaft portion 3, so that the riverbed forming block 1a can be independently provided on the excavation surface 6. Have. Therefore, when a plurality of riverbed forming blocks 1a are arranged for the purpose of forming an artificial riverbed, the riverbed forming blocks are simply lifted one by one by a crane or the like and placed on the excavation surface 6. Since the arrangement | work operation | work of 1a can be completed, it has the effect that workability | operativity in a construction site can be improved.

Further, as shown in FIG. 1 (b), the riverbed forming block according to the present invention has columnar shaft portions 3 connected to the lower surface side of the rod-shaped flow conductor 2a and in the vicinity of both ends, respectively. The leg portions 4 may be provided in the vicinity of the end portion on the side not connected to the flow conductor 2a and in the circumferential direction thereof.
As shown in FIG. 1B, the riverbed forming block 1b according to the second embodiment also has the effect of being able to stand on the excavation surface 6 in a stable manner by including the shaft portion 3 and the leg portion 4. Have.
A plurality of the riverbed forming blocks 1a and 1b having the above-described configuration are arranged on the excavated surface 6 that has been excavated and flattened, and then to the bottom surfaces of the flow conductors 2a and 2a, that is, FIGS. ) Is filled up with a riverbed forming material (not shown) to the height of the plane indicated by the symbol A in FIG.

Conventionally, it has been known that in natural rivers, scouring occurs where the riverbed is gradually scraped off by the stream of river water, and the riverbank is eroded.
As riverbed scouring and riverbank erosion progressed, weirs installed in the middle of rivers and embankments formed on riverbanks lost their support bases, causing flooding due to collapse and damage during floods.
In particular, in order to prevent scouring of the riverbed, it is effective to form a plurality of protrusions on the riverbed to disturb the river flow and reduce the river flow velocity at the riverbed.
On the other hand, if you simply install an object that becomes a protrusion on the river bed, the object that makes up the protrusion will be easily washed away by the water pressure during floods, and in the event of an emergency, it may not be possible to expect the effect of reducing the flow velocity of the water flow. The nature was high.
Therefore, the inventors provided a structure for supporting the projection when arranging the projection for reducing the flow velocity of the river water on the river bed, and by accommodating this structure in the ground of the river bed, An artificial riverbed was devised that can increase the resistance of the projections to the water pressure, and at the same time, use the structure embedded in the riverbed as the framework structure of the riverbed to prevent the movement of the riverbed forming material due to the water flow.

Therefore, according to the riverbed forming blocks 1a and 1b according to the first and second embodiments, the shaft 3 and the leg 4 are accommodated in the ground of the riverbed, so that the flow conductor 2a projecting into the water from the riverbed. , 2a can be improved in resistance to water pressure.
Moreover, the flow conductor 2a has the effect | action which disturbs the water flow near a river bed, As a result, it has the effect that the water flow of a river water is disturbed and a flow velocity is reduced.
Moreover, the axial part 3 and the leg part 4 which concern on the riverbed formation blocks 1a and 1b which concern on Example 1 and Example 2 form a frame structure in the riverbed of a river, and riverbed formation materials, such as earth and sand, move by a water flow. It has the effect that it can prevent.
Therefore, according to the river bed forming blocks 1a and 1b according to the first and second embodiments, the water flow is disturbed by the flow conductor 2 and the river bed forming material is held by the shaft portion 3 and the leg portion 4 so as to be washed with water flow. It has the effect of providing an artificial river bed that is not easily dug.
In addition, in FIG. 1, although the case where the flow conductor 2 has one or two shaft portions has been described as an example, the shaft portion 3 is not limited to the illustrated number, and three or more shaft portions may be used. good.
In particular, when three or more shaft portions 3 are provided on the flow conductor 2a and when the riverbed forming block according to the first embodiment can be self-supporting, the shaft portions 3 do not necessarily have to be provided with the leg portions 4. In this case, since the shaft part 3 also serves as the function and effect of the leg part 4, it has the same function and effect as the river bed forming blocks 1a and 1b.
Further, the legs projecting in the circumferential direction in the vicinity of the end of the shaft portion 3 are formed on the excavation surface 6 of the riverbed without using the struts or the like for the riverbed forming blocks 1a and 1b according to the first and second embodiments. If it is arranged so as to be able to stand on its own, its installation position and number are not a problem.

Here, a modified example of the flow conductor 2a will be described with reference to FIG.
2 (a) to 2 (d) are conceptual diagrams showing modifications of the flow guide portion according to the present invention.
In FIG. 1, the case where the shape of the flow conductor 2a is, for example, a straight line is described as an example. However, the shape of the flow conductor 2a is not necessarily a straight line.
For example, the flow conductor 2b shown in FIG. 2 (a) may be curved in a substantially arc shape, or a plurality of polygonal sides may be cut out like the flow conductor 2c shown in FIG. 2 (b). It may be a curved shape.
Alternatively, it may be bent in a substantially square shape like a flow conductor 2d shown in FIG. 2C, or may be bent in a zigzag shape like a flow conductor 2e shown in FIG. 2D. .
In particular, the flow conductor 2a as shown in FIG. 1 and the flow conductors 2a to 2e as shown in FIG. When the water flow B is arranged in the downstream direction and in the direction of blocking the water flow, as shown in FIG. 2, the water flow B flowing from the upstream side of the river and the water flow C trying to get over the flow conductors 2a to 2e The flow conductors 2a to 2e have the effect of being able to be divided and disturbed by the water flow D whose direction is changed along the extending direction.
As a result, the water flow C in FIG. 2 acts to cancel the momentum of the water flow B in the vertical direction of the river while forming an upward flow from the river bed 9 to the water surface. Further, the water flow D acts so as to cancel the momentum of the water flow B in the plane direction of the river bed 9.
Therefore, these actions are combined, and the effect of reducing the flow velocity of the water stream B is exhibited.
Note that the flow conductors 2b to 2e according to the above-described modifications can be replaced with the flow conductors of the riverbed forming blocks according to other embodiments.

Next, the riverbed forming block according to the third and fourth embodiments will be described in detail with reference to FIG. (Particularly corresponding to claim 2)
FIG. 3 is a conceptual diagram of a river bed forming block according to a third embodiment of the present invention, and FIG. 3B is a conceptual diagram of a river bed forming block according to the fourth embodiment. In addition, the same code | symbol is attached | subjected about the same part as what was described in FIG. 1 or FIG. 2, and the description about the structure is abbreviate | omitted.
As shown in FIGS. 3A and 3B, the river-bed forming blocks 1c and 1d according to the third and fourth embodiments have the same configuration as the river-bed forming block according to the first or second embodiment described above. The at least one bar-shaped or flat-shaped branch portion 5 is provided on the side surface of the shaft portion 3 between the flow conductor 2a and the leg portion 4 so as to be suspended or inclined.
In FIGS. 3A and 3B, the case where the shaft portions 3 of the river-bed forming blocks 1c and 1d according to the third and fourth embodiments are rod-shaped is described as an example. 5 may be, for example, a flat plate-like branch having a plane in a direction parallel to the length direction of the shaft portion 3, or parallel to the excavation surface 6 as an installation surface, or intersecting the excavation surface 6. It may be a flat branch having a flat surface.
Moreover, in FIG.3 (b), although the branch part 5 is protrudingly provided in the same direction as the protruding direction of the leg part 4, this, for example, connects the riverbed formation block 1d which concerns on Example 4 to each other, for example. This is because the branch portions 5 of the adjacent river-bed forming blocks 1d are arranged so that a plurality of them can be arranged in contact with each other.
Furthermore, in FIG.3 (b), you may provide the branch part 5 only in any one of the axial parts 3 of the riverbed formation block 1d which concerns on Example 4. FIG.
In this case, although the effect of preventing the separation of the riverbed forming block 1d according to the fourth embodiment from the riverbed 9 is reduced, the plurality of riverbed forming blocks 1d according to the fourth embodiment are easily arranged on the excavation surface 6. It has the effect that workability at the time of construction can be improved.
Therefore, the branch portions of the river-bed forming blocks 1c and 1d according to the third or fourth embodiment may be provided anywhere on the side surface of the shaft portion 3 as long as the branch portions are not obstructed when arranged on the excavation surface 6 of the river bed. The number may be one or more.
In the specification of the present application, among the protrusions protruding from the shaft portion 3, the protrusions necessary for the self-supporting of the river bed forming block according to the present invention are defined as the leg portions 4, and the other protrusions are defined as the branch portions 5, and these are divided. Separated. The same applies to other examples described in the present specification.

Thus, in the river-bed formation blocks 1c and 1d according to Examples 3 and 4, when the shaft portion 3 is accommodated in the ground of the river bed by providing the branch portion 5 in the shaft portion 3, the river-bed forming material. In addition, the contact area with the river-bed forming blocks 1c and 1d according to the third and fourth embodiments is increased, and the resistance when the water flow acts on the flow conductor 2a can be increased.
As a result, it is possible to reduce the possibility that the riverbed forming blocks 1c and 1d according to the third and fourth embodiments will be detached from the riverbed during a flood.
Further, the increase in the contact area between the riverbed forming blocks 1c, 1d according to the third and fourth embodiments and the riverbed forming material means that the riverbed forming material holding effect by the riverbed forming blocks 1c, 1d is enhanced. This means that an artificial riverbed having a higher scouring prevention effect than the riverbed forming blocks 1a and 1b according to the first and second embodiments can be provided.
It can be said that the greater the number of branches 5, the higher the resistance to water pressure of the river bed forming block 1c or 1d, and the higher the retention effect of the river bed forming material.

  In particular, when the branch portions 5 of the riverbed forming blocks 1c and 1d according to the third and fourth embodiments are provided in the vicinity of the flow conductor 2a, and both the flow conductor 2a and the branch portion 5 are protruded from the river bed into the water, Since the water flow can be disturbed also by the branch part 5, it has the effect that the speed reduction effect of a water flow can be accelerated | stimulated.

Subsequently, the riverbed forming blocks according to the fifth and sixth embodiments will be described in detail with reference to FIGS. 4 and 5. (Particularly corresponding to claim 3)
FIG. 4 is a conceptual diagram of a riverbed forming block according to Embodiment 5 of the present invention, and FIG. 4B is a plan view thereof. FIG. 5 is a conceptual diagram of a river bed forming block according to Embodiment 6 of the present invention, and (b) is a plan view thereof. The same parts as those described in FIGS. 1 to 3 are denoted by the same reference numerals, and description of the configuration is omitted.
As shown in FIG. 4A, the riverbed forming block 1e according to the fifth embodiment is obtained by replacing the flow conductor 2a of the riverbed forming block 1c according to the third embodiment with the flow conductor 2b shown in FIG. is there. The flow conductor of the riverbed forming block 1e according to the fifth embodiment may be the flow conductor 2c shown in FIG.
Furthermore, in addition to the above-described configuration, the riverbed forming block 1e according to the fifth embodiment includes two central axes 16 and 17 at both ends 15a and 15b of the flow conductor 2b and the branch portion 5 as shown in FIG. When the center axis 18 is projected onto the same plane perpendicular to the shaft portions 16 and 17, the angle between the three center axes 16, 17 and 18 is 120 °.
Furthermore, as shown in FIGS. 5A and 5B, the riverbed forming block 1f according to the sixth embodiment is different from the flow-forming block shown in FIG. 2C in the 2b of the riverbed forming block 1e according to the fifth embodiment. It is replaced with 2d.

Further, in the riverbed forming block 1e according to the fifth embodiment, the upper surface of the branch portion 5 is disposed at a position lower than the upper surface of the flow conductor 2b.
Then, the end 15a or 15b of the flow conductor 2b related to the other riverbed forming block 1e can be placed on the upper surface of the branch portion 5, so that the height of the branch portion 5, that is, the upper surface of the branch portion 5 in the shaft portion 3 is increased. By setting the height to a position that is twice as low as the thickness of the flow conductor 2e from the height of the upper surface of the flow conductor 2b, a plurality of riverbed forming blocks 1e can be installed in a self-supporting state. The riverbed forming block 1e is connected to form an integral frame structure.
The riverbed forming block 1f according to the sixth embodiment has the same operation and effect.

FIG. 6 is a conceptual diagram illustrating an example of a state in which a plurality of riverbed forming blocks according to the sixth embodiment are provided in series. The same parts as those described in FIGS. 1 to 5 are denoted by the same reference numerals, and description of the configuration is omitted. Moreover, in FIG. 6, description of a part of shaft part and a leg part was abbreviate | omitted so that the positional relationship of the flow conductor at the time of connecting the riverbed formation block which concerns on Example 6 may be understood easily.
As shown in FIG. 6, for example, according to the riverbed forming block 1f according to the sixth embodiment, the flow conductor 2d related to another riverbed forming block 1f is formed on the upper surface of the branch portion 5 related to the riverbed forming block 1f. When the plurality of river-bed forming blocks 1f are continuously provided while the end portions 15a and 15b are placed, there is an effect that an integral frame structure assembled in a hexagonal lattice shape can be formed on the river bed.
And, if the riverbed forming block 1f according to the sixth embodiment is formed of, for example, a reinforced concrete load having a large load, the strength of the riverbed framework structure can be increased.
Further, when the riverbed forming block 1f according to the sixth embodiment is formed of a relatively light material such as a metal material, a riverbed forming block according to the sixth embodiment is used by using a connector or welding. It is possible to connect If together.
In any case, since the plurality of riverbed forming blocks 1f function as an integral structure in the riverbed, the shape retention effect of the riverbed can be enhanced.
The riverbed forming block 1e according to the fifth embodiment and the riverbed forming block obtained by replacing the flow conductor 2b of the riverbed forming block 1e with the flow conductor 2c shown in FIG. It has the same operation and effect as the block 1 f for use.

Here, the mechanism in which the riverbed forming blocks 1a to 1f according to the first to sixth embodiments exert the effect of reducing the flow velocity in the riverbed will be described in detail with reference to FIG.
Fig.7 (a) is sectional drawing at the time of installing the riverbed formation block based on Example 1 of this invention in a riverbed, (b) is a case where the attachment angle of a shaft part is changed in Fig.7 (a). It is sectional drawing which shows an example.
As shown in FIG. 7, the river-bed forming block 1 a according to the first embodiment is installed in a state of being self-supporting on a drilling surface 6 formed by excavating a conventional river bed, and the shaft portion 3 and the leg portion 4 are provided. It is used in a state in which the riverbed 9 is formed by being backfilled with the riverbed forming material 7 and at substantially the same height as the lower surface of the flow conductor 2a.
In this state, when the river water 8 flows on the river bed 9, a water flow is generated in the direction indicated by the symbol B in FIG.
At this time, in the vicinity of the flow conductor 2a projecting from the upper surface of the river bed 9, a water flow C trying to get over the flow conductor 2a and a water flow (not shown) redirected along the extending direction of the flow conductor 2a are generated. A separation flow 19 is generated on the downstream side of the conductor 2a by the action of the water flow C.
Then, the force of the water flow B is weakened by the separation flow 19 and the water flow whose direction is changed (not shown), and the flow velocity of the river water 8 is reduced.

At this time, the water pressure acting on the flow conductor 2a by the water flow B is transmitted to the leg portion 4 through the shaft portion 3, but the shaft portion 3 and the leg portion 4 are retained by the river bed forming material 7, There is no worry that the flow conductor 2a is detached or moved.
In particular, since the leg portion 4 also acts as a resistance material that prevents the shaft portion 3 from being detached, the riverbed forming block 1a according to the first embodiment also has the shape retention effect of the riverbed 9.
Further, the leg portion 4 of the shaft portion 3 also has a function as a support column for allowing each of the river bed forming blocks 1a to be independent.
Therefore, in the riverbed forming block 1a according to the first embodiment, the flow conductor 2a protruding in the river water 8 and the shaft portion 3 and the leg portion 4 accommodated in the ground of the riverbed 9 are provided for the first time. The effect of reducing the flow velocity of the water stream B, the effect of maintaining the shape of the riverbed 9 and the effect of improving workability during construction are exhibited.
The same applies to the river-bed forming blocks 1b to 1f according to Examples 2 to 6.
In particular, according to the riverbed forming blocks 1c to 1f according to Examples 3 to 6 having the branch portion 5 in the shaft portion 3, the riverbed forming material 7 and the riverbed forming blocks 1c to 1f are provided by having the branch portion 5. The contact area increases, and the riverbed shape retention effect can be further promoted.

In the river-bed formation blocks 1a to 1f according to the above-described Examples 1 to 6, the case where the shaft portion 3 is suspended from the flow conductors 2a to 2e has been described as an example. For example, as shown in FIG. 7 (b), the shaft portion 3 is arranged with respect to a plane in which the current conductors 2 a to 2 e extend, that is, a plane parallel to the river bed 9. You may connect in the state inclined.
In this case, the riverbed forming block 1g according to the modification has the same effect as the riverbed forming block 1a according to the first embodiment.
In the riverbed forming block 1g according to the modification, the flow conductor 2 is replaced with the flow conductors 2b to 2e described in FIGS. 2A to 2D, and the same as the riverbed forming block 1a according to the first embodiment. The effect can be expected.
Furthermore, in this case, when the riverbed forming block 1g according to the present invention is self-supported, it is necessary to provide the leg 4 so as to support the inclined shaft portion 3 so that the riverbed forming block 1g does not roll over.
On the other hand, since the end 3a on the side not connected to the flow conductor 2a of the shaft portion 3 can be used as a leg portion, the riverbed forming block 1g can be obtained by projecting at least two legs 4 from the shaft portion 3. It has the effect of being able to be independent.

The structure of the river bed according to Example 7 will be described in detail with reference to FIG. (Particularly corresponding to claim 4)
The riverbed structure according to the seventh embodiment is a riverbed structure using a plurality of the riverbed forming blocks 1a to 1f according to the first to sixth embodiments, and is an end portion of the flow guide portions 2a to 2e. Any one of the central axes is arranged on the river bed in the downstream direction of the river and in the direction of blocking the water flow.
In this way, a plurality of flow conductors related to the riverbed forming block according to the present invention are regularly arranged on the riverbed in a state in which the extending direction is directed to a certain direction, thereby guiding the flow of the river water in a desired direction. It has the effect that it can be done.

Here, a case where the riverbed structure according to the seventh embodiment is formed using the riverbed forming block 1a according to the first embodiment will be described as an example.
FIGS. 8A to 8C are plan views showing the structure of a river bed according to Example 7 of the present invention. The same parts as those described in FIGS. 1 to 7 are denoted by the same reference numerals, and description of the configuration is omitted.
FIG. 8A shows a case where the river bed structure according to the seventh embodiment is formed on the river bed 9 having a straight flow path.
As shown in FIG. 8 (a), the riverbed structure 14a according to the seventh embodiment has the riverbed 9 with the central axis of one end of the flow conductor 2a in the direction of blocking the water flow B in the downstream direction of the river. That is, in particular, in FIG. 8A, it is directed to the center 11 side of the river.
In this case, there is an effect that the direction of the water flow B can be changed in the direction toward the center 11 of the river (in the direction indicated by the symbol E in the drawing).
As a result, the river water pressure toward the river bank 10 is weakened, and the river bank 10 can be prevented from being damaged during a flood.
In the riverbed structure 14a according to the seventh embodiment, since the shaft portion 3 and the leg portion 4 (not shown) are accommodated in the ground of the riverbed 9 to form a framework structure, the riverbed forming material 7 is retained by this framework structure. Therefore, the scouring of the riverbed 9 does not occur.
Therefore, according to the riverbed structure 14a according to the seventh embodiment, first, the flow velocity of the water flow B is reduced by the individual flow conductors 2a acting as resistors against the water flow in the water, and then the plurality of flow conductors 2a are formed. The effect that the flow of the water flow B is changed to a desired direction is exhibited by being directed in a certain direction and being regularly arranged. Furthermore, the riverbed 9 can be prevented from being scoured by arranging the plurality of riverbed forming blocks 1a in the riverbed 9 in a mesh pattern.
In addition, for example, when the riverbed forming block 1a according to the first embodiment is made of reinforced concrete, the durability of the riverbed structure 14a according to the seventh embodiment can be improved.
In other words, once the riverbed structure 14a according to the seventh embodiment is formed, there is an effect that it can be used permanently.

FIG. 8B shows a case where the river bed structure according to the seventh embodiment is formed on the river bed 9 having a curved flow path. In the river of FIG. 8 (b), the river bank on the right hand side when standing back to the upstream side of the river is referred to as the right bank 10a, and the river bank on the left hand side is referred to as the left bank 10b.
In the case of this figure, the river bed 9 has the central axis of one end of the flow conductor 2a in the downstream direction of the river and in the direction blocking the water flow B, that is, particularly in FIG. 8B, on the right bank 10a side. It is characterized by being directed to. In FIG. 8B, the flow conductor 2a is arranged near the left bank 10b of the river rather than the center 11, but the flow conductor 2a is also arranged on the right bank 10a side of the river toward the right bank 10a of the river. May be. The same applies to the riverbed structure 14b described later with reference to FIG. 9B.
As shown in FIG. 8B, the river bed structure 14a according to the seventh embodiment may be formed on a river bed 9 having a curved flow path. Here, an explanation will be given with an emphasis on the difference from the case where the riverbed structure according to the seventh embodiment is formed on the riverbed 9 of the river having a straight flow path.
In general, when a river has a curved channel, the left bank 10b of the river tends to be eroded. On the other hand, on the right bank 10a of the river, there is a tendency for earth and sand carried by the water flow to accumulate.
For this reason, protection of the left bank 10b is the most important issue when the river is bent.
Therefore, in order to protect the left bank 10b of the river, it is desirable to form the river bed structure 14a according to the seventh embodiment at least on the left bank 10b side. In this case, in addition to the protection effect of the river bed from the center 11 of the river to the left bank 10b, this portion has the effect of guiding the water flow to the center 11 side of the river.

In addition, the water flow forms a special channel in a portion facing the left bank 10b of the river having a curved channel.
That is, as shown in FIG. 8 (c), while the river water flows down toward the left bank 10b near the river surface (see the solid line portion of the arrow in FIG. 8 (c)), this water flow is on the left bank 10b. The course changes to flow toward the riverbed 9 and then flows down in the riverbed 9 from the left bank 10b toward the center 11 (see the broken line portion of the arrow in FIG. 8C). .
Since the water flow that suddenly changes direction on the left bank 10b acts to scavenge the left bank 10b and its riverbed 9, scouring occurs in the riverbed 9 on the left bank 10b.
Therefore, especially in a river having a curved flow path, the flow conductor 2a is arranged on the river bed 9 facing the left bank 10b, and the central axis of one end thereof is arranged on the downstream side of the river and toward the left bank 10b. The water flow acting so as to turn the riverbed 9 facing the left bank 10b can be blocked by the flow conductor 2a. As a result, the riverbed 9 facing the left bank 10b can be prevented from being scoured.
Of course, this case also has the effect of reducing the flow velocity B of the water stream.

The structure of the river bed according to Example 8 will be described in detail with reference to FIG. (Particularly corresponding to claim 5)
Here, a description will be given with emphasis on differences from the riverbed structure according to the seventh embodiment.
In addition, although any of the riverbed forming blocks according to the first to sixth embodiments can be used for the riverbed structure according to the eighth embodiment, the riverbed forming block 1a according to the first embodiment is particularly used here. Will be described as an example.
Further, the riverbed structure according to the eighth embodiment is formed by connecting the ends of the flow conductors 2a of the riverbed structure according to the seventh embodiment while contacting each other or overlapping each other to form an integrated continuous body. It is characterized by that.
FIGS. 9A and 9B are plan views showing the structure of a river bed according to Example 8 of the present invention. The same parts as those described in FIGS. 1 to 8 are denoted by the same reference numerals, and description of the configuration is omitted.
The riverbed structure 14b according to the eighth embodiment has the same actions and effects as the riverbed structure according to the seventh embodiment, and the water flow that has reached the flow conductor 2a by regularly arranging the connecting bodies 12a on the riverbed 9. There is an effect that B can be continuously guided in a desired direction.
That is, referring to FIGS. 9A and 9B, the water flow B can be continuously guided to the center 11 side of the river.
Therefore, it can be said that the river bed structure 14b according to the eighth embodiment has a higher water flow channel change effect than the river bed structure 14a according to the seventh embodiment.
Although not particularly illustrated, for the reason described with reference to FIG. 8C, in the river bed structure 14b according to the eighth embodiment, the flow conductor 2a located in the vicinity of the end on the left bank 10b side of the connecting body 12a. That is, the flow conductor 2a arranged on the river bed 9 facing the left bank 10b in FIG. 9B is arranged with the central axis of the end on the left bank 10b side downstream of the river and toward the left bank 10b. May be.
In this case, in addition to the effect that the riverbed 9 facing the left bank 10b can be prevented from being scoured, it also has the effect of reducing the flow velocity B of the water stream.

Further, a method for connecting a plurality of river bed forming blocks 1a in the river bed structure 14b according to the eighth embodiment will be described in more detail with reference to FIGS.
FIG. 10A is a plan view showing a state in which the flow conductors of the riverbed forming block according to the first embodiment are arranged in contact with each other, and FIG. 10B is a side view thereof. The same parts as those described in FIGS. 1 to 9 are denoted by the same reference numerals, and description of the configuration is omitted.
As shown in FIGS. 10 (a) and 10 (b), when the riverbed forming block 1a according to the first embodiment is continuously connected while the side surface of the flow conductor 2a is in contact, the side surface of the continuous body 12a is stepped. It becomes.
Therefore, since the side surface shape of the connecting body 12a is complicated, the disturbance of the water flow in the plane direction of the river bed 9 is promoted, and the flow velocity of the river water is reduced.
Further, when the connecting body 12a is formed while the side surfaces of the end portions of the flow conductor 2a are in contact with each other, the riverbed forming block 1a is supported by each other, so that the shape retention effect of the riverbed 9 is also promoted. .

Moreover, Fig.11 (a) is a top view which shows the mode at the time of arranging the flow conductors of the river-bed formation block based on Example 1 mutually overlapping, and (b) is the side view. The same parts as those described in FIGS. 1 to 10 are denoted by the same reference numerals, and description of the configuration is omitted.
As shown in FIGS. 10 (a) and 10 (b), when the riverbed forming block 1a according to the first embodiment is connected while overlapping the end portions of the flow conductor 2a, the upper surface of the connecting body 12b is stepped. It becomes.
For this reason, the shape of the upper surface of the continuous body 12b is complicated, and at the same time, the height of the protrusion from the river bed 9 is increased, so that the disturbance of the water flow in the vertical direction of the river bed 9 is promoted, and the flow velocity of the river water is reduced. Has the effect of being
Further, when the riverbed forming blocks 1a are connected to each other while the ends of the flow conductors 2a are overlapped with each other to form the continuous body 12b, the riverbed forming blocks 1a support each other. The shape retention effect is also promoted.
In this case, even when the flow conductors 2a are arranged while being overlapped, the flow conductor 2a is inclined with respect to a plane parallel to the river bed 9 in the shaft portion 3 so that the river bed forming block 1a can be surely self-supported. You may connect in the state.

The structure of the river bed according to Example 9 will be described in detail with reference to FIG. (In particular, it corresponds to claims 6 and 8.)
The riverbed structure according to the ninth embodiment is a riverbed structure using a plurality of the riverbed forming blocks according to the third to sixth embodiments, and the flow conductor of the riverbed forming block according to the third to sixth embodiments. And the branch portion is arranged in a state of being bare on the riverbed.

FIG. 12A is a conceptual diagram illustrating an example of a river bed structure according to the ninth embodiment, and FIG. 12B is a conceptual diagram illustrating another example of the river bed structure according to the ninth embodiment. The same parts as those described in FIGS. 1 to 11 are denoted by the same reference numerals, and description of the configuration is omitted.
The riverbed structure 20a according to the ninth embodiment includes, for example, as shown in FIG. 12A, the end portions of the flow conductor 2a of the riverbed forming block 1c according to the third embodiment are overlapped and connected to each other. The shaft part 3 and the leg part 4 are accommodated in the ground of the river bed 9 so that 5 is exposed on the river bed 9.
In this case, the flow conductor 2a is continuously provided, thereby having an effect that the flow path switching of the water flow is promoted. In addition, since the upper surface of the continuous body 12c is stepped, the disturbance of the water flow in the vertical direction of the river bed 9 is promoted. Furthermore, since the branch part 5 is exposed on the upper surface of the river bed 9, there is an effect that disturbance of water flow in the plane direction of the river bed 9 is also promoted.
Combining these effects, the river flow velocity reduction effect is further promoted.
In addition, in the riverbed structure 20a shown to Fig.12 (a), the branch part 5 may be separately provided in the axial part 3, and this branch part 5 may be accommodated in the ground. In this case, it has the effect that the resistance with respect to the water pressure of the riverbed structure 20a can be improved.
Further, in the river bed structure 20a shown in FIG. 12A, the river bed forming block 1c is not necessarily provided continuously.

Further, as shown in FIG. 12B, the riverbed structure 20b according to the ninth embodiment uses the riverbed forming block 1f according to the sixth embodiment, and the end of the flow conductor 2d is placed on the upper surface of the branch portion 5. The shaft portion 3 and the leg portion 4 may be accommodated in the ground of the river bed 9 so as to be continuously provided while being placed, and so that the branch portion 5 is barely exposed on the river bed 9.
In this case, since a structure having a complicated shape can be formed on the river bed 9, the water flow can be suitably disturbed in both the plane direction and the vertical direction of the river bed 9, and a high flow velocity reduction effect and the river bed 9 can be obtained. Can be expected to prevent scouring.
In the riverbed structure 20b shown in FIG. 12 (a), a branch portion 5 may be separately provided in the shaft portion 3, and the branch portion 5 may be accommodated in the ground. In this case, it has the effect that the resistance with respect to the water pressure of the riverbed structure 20b can be improved.

In addition, in the structure of the riverbed which concerns on Examples 7-9, you may use an irregular natural stone as a riverbed formation material which forms the riverbed 9. FIG.
In this case, it has the effect that many clearance gaps can be formed in the surface of the riverbed 9, and its inside.
This gap serves as a habitat for living organisms inhabiting the river, and thus has an effect that the river ecosystem can be maintained even in the artificially formed river bed 9.
Moreover, since the riverbed 9 formed by assembling irregular natural stones has a strong shape-retaining property, the riverbed structure according to Examples 7 to 9 is given strong resistance to scouring action. It has the effect that it can be done. Moreover, it has the effect that it can be made hard to detach | leave the riverbed formation block which concerns on this invention from the riverbed 9 with the load of a natural stone.
Therefore, by combining a stone bed made of natural stone with the riverbed structure according to Examples 7 to 9, the shape retention of the river is further improved, the direction of the flow path can be changed, and the river ecosystem is preserved. It is possible to provide an artificial riverbed that can simultaneously realize the three effects of being able to. In this case, the durability of the artificial riverbed can be further improved.

Finally, a river bed forming method according to Embodiment 10 of the present invention will be described in detail with reference to FIGS. (In particular, it corresponds to claims 7 and 8.)
The method for forming a river bed according to Example 10 of the present invention is an invention relating to a method for forming the structure of a river bed according to Example 7 or Example 8 described above, and is substantially the river bed according to Example 7 or Example 8. It has the same action and effect as the structure.
13 to 15 are conceptual diagrams showing how an artificial riverbed is formed by the riverbed forming method according to the tenth embodiment. The same parts as those described in FIGS. 1 to 12 are denoted by the same reference numerals, and description of the configuration is omitted.
In the river-bed formation method according to the tenth embodiment, any of the above-described river-bed forming blocks 1a to 1f according to the first to sixth embodiments can be used, but here, the river-bed forming block 1f according to the sixth embodiment is particularly used. The case where an artificial riverbed is formed using will be described as an example.
In FIGS. 5 and 6 described above, the flow conductor 2d and the shaft portion 3, and the leg portion 4 and the branch portion 5 of the river-bed forming block 1f according to the sixth embodiment are formed as square pillars. However, these may be, for example, hexagonal columns that are multiple columns other than a quadrangular column, or a cylinder. The same applies to the river-bed forming blocks 1a to 1e according to the first to fifth embodiments.

In order to form an artificial riverbed by the riverbed forming method according to the tenth embodiment, first, the riverbed to be constructed is exposed by damming the waterflow of the river or bypassing the waterflow.
Next, an excavation process is provided in the ground of the river bed to be constructed for the purpose of accommodating the shaft part 3 and the leg part 4 of the river bed forming block 1f according to Example 6, and the river bed to be constructed is dug down. The excavation surface 6 is formed.
Subsequently, as shown in FIG. 13, a plurality of riverbed forming blocks 1 f according to the sixth embodiment are arranged on the excavation surface 6. In this arrangement step, the riverbed forming blocks 1f may be arranged to stand independently while overlapping the end portions of the flow conductors 2d of the other riverbed forming blocks 1f on the branches 5 of the riverbed forming blocks 1f. desirable.
In this case, the riverbed 9 has an integral framework structure, and the shape retention of the riverbed 9 is enhanced, and at the same time, the riverbed 9 has an effect of improving resistance to scouring.
In this arrangement step, one end of the flow conductor 2d of the river bed forming block 1f may be directed to the downstream side of the river and in the direction of blocking the flow of the river water. In this case, the plurality of flow conductors 2d are arranged regularly on the river bed 9 in a certain direction, and thus the river water can be guided in a desired direction.
Further, in the arranging step, the end portions of the flow conductor 2d of the riverbed forming block 1f may be connected while being overlapped. In this case, the flow path changing effect and the river flow velocity reduction effect by the flow conductor 2d are enhanced. it can.

Further, in the embedding process provided after the disposing process, as shown in FIG. 14, first, the leg portion 4 of the river bed forming block 1f is backfilled with the river bed forming material 7 and formed with a plurality of river bed forming blocks 1f. After the frame structure to be stabilized is stabilized, the riverbed 9 is backfilled with the riverbed forming material 7 again to the vicinity of the upper surface of the branch portion 5 of the riverbed forming block 1f.
In this embedding process, in particular, when the riverbed 9 is formed by a stone assembly using an unnatural natural stone 13, a gap is formed in the riverbed 9, and this gap becomes a trap for aquatic organisms. Also has the effect of preserving the river ecosystem.

  The riverbed forming block and the riverbed structure using the same according to the present invention can improve the shape retention of the formed artificial riverbed and prevent scouring due to water flow. It can be guided in a desired direction to mitigate the erosion action of the riverbank, and can be used in the field related to the construction of artificial riverbeds and artificial coasts.

(A) It is a conceptual diagram of the block for riverbed formation concerning Example 1 of this invention, (b) is a conceptual diagram of the block for riverbed formation concerning Example 2. FIG. (A)-(d) is a conceptual diagram which shows the modification of the flow guide part which concerns on this invention. It is a conceptual diagram of the riverbed formation block which concerns on Example 3 of this invention, (b) is a conceptual diagram of the riverbed formation block which concerns on Example 4. FIG. It is a conceptual diagram of the block for riverbed formation which concerns on Example 5 of this invention, (b) is the top view. It is a conceptual diagram of the block for riverbed formation which concerns on Example 6 of this invention, (b) is the top view. It is a conceptual diagram which shows an example of the state which connected the block for riverbed formation concerning Example 6 continuously. (A) It is sectional drawing at the time of installing the riverbed formation block concerning Example 1 of this invention in a riverbed, (b) shows an example at the time of changing the attachment angle of a shaft part in Fig.7 (a). It is sectional drawing. (A)-(c) is a top view which shows the structure of the river bed which concerns on Example 7 of this invention. (A), (b) is a top view which shows the structure of the river bed which concerns on Example 8 of this invention. (A) It is a top view which shows the mode at the time of arranging continuously, making the flow conductor of the riverbed formation block which concerns on Example 1 contact, (b) It is the side view. (A) It is a top view which shows the mode at the time of connecting in series, laminating | stacking the flow conductor of the riverbed formation block which concerns on Example 1, (b) It is the side view. (A) It is a conceptual diagram which shows an example of the structure of the river bed concerning Example 9, (b) It is a conceptual diagram which shows the other example of the structure of the river bed concerning Example 9. FIG. It is a conceptual diagram which shows a mode that the artificial riverbed is formed with the formation method of the riverbed which concerns on Example 10. FIG. It is a conceptual diagram which shows a mode that the artificial riverbed is formed with the formation method of the riverbed which concerns on Example 10. FIG. It is a conceptual diagram which shows a mode that the artificial riverbed is formed with the formation method of the riverbed which concerns on Example 10. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a-1g ... River-bed formation block 2a-2e ... Current conductor 3 ... Shaft part 3a ... End part 4 ... Leg part 4a ... End part 5 ... Branch part 6 ... Excavation surface 7 ... River bed forming material 8 ... River water 9 ... River bed 10 ... River bank 10a ... Right bank 10b ... Left bank 11 ... Center 12a, 12b ... Linked body 13 ... Natural stone 14a, 14b ... River bed structure 15a, 15b ... End 16-18 ... Center axis 19 ... Separation flow 20a, 20b ... River bed Structure 21 ... central axis

Claims (8)

A bed forming block arranged to act on the flow of river water in the river bed,
A rod-shaped and straight or curved or bent flow guiding portion;
At least one shaft portion fixed to the flow guide portion;
A riverbed forming block comprising: at least one leg projecting in the circumferential direction in the vicinity of an end portion of the shaft portion where the flow guide portion is not provided.   The shaft portion includes at least one rod-like or flat plate-like branch portion that is suspended or obliquely provided between the flow guide portion and the leg portion and in a circumferential direction of the shaft portion. Item 1. A riverbed forming block according to Item 1. A bed forming block arranged to act on the flow of river water in the river bed,
One flow guide portion that is rod-shaped and curved or bent;
At least one shaft portion fixed to the flow guide portion;
At least one leg protruding in the circumferential direction in the vicinity of the end of the shaft portion on the side where the flow guide portion is not provided;
One rod-like or flat plate-like branch portion that is suspended or obliquely provided between the flow guide portion and the leg portion of the shaft portion and in the circumferential direction of the shaft portion,
The two central axes at both ends of the flow guide part and the central axis of the branch part are formed at an angle of 120 ° between the three central axes when projected onto the same plane perpendicular to the shaft part. A riverbed forming block characterized by that. A riverbed structure comprising a plurality of riverbed forming blocks according to any one of claims 1 to 3,
A riverbed structure characterized in that either one of the end portions of the flow guide portion is arranged on the riverbed in the downstream direction of the river and in the direction of blocking the water flow.   The riverbed structure according to claim 4, wherein the end portions of the flow guide portions are continuously provided in contact with each other or overlapped with each other. A riverbed structure comprising a plurality of riverbed forming blocks according to claim 2 or claim 3,
A structure of a river bed, wherein the flow guide part and the branch part are arranged in a state of being bare on the river bed. A drilling process to dig down the riverbed;
A disposing step of disposing a riverbed forming block according to any one of claims 1 to 3 on the riverbed after this step;
A method for forming a river bed, comprising a step of burying the shaft portion in a state where the flow guide portion or the flow guide portion and the branch portion are exposed on the river bed after this step.   8. The river bed forming method according to claim 7, wherein natural stone is used as a river bed forming material when the shaft portion is buried in the river bed in the embedding step.