JP3662186B2 - Transmission type dam unit and transmission type dam - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transmission-type dam unit and a transmission-type dam that have been developed especially for debris flow countermeasures.
[0002]
[Prior art]
As is well known, many sabo dams have been installed in the past to prevent devastation in mountainous areas due to sudden sediment runoff and deterioration of water storage function due to stagnant sand, and concentration due to rainy seasons, typhoons, etc. It is a place that should be installed immediately to protect private houses, facilities, roads, etc. from debris flow caused by heavy rain.
[0003]
The debris flow here is a fluid in which the transport mode of sediment is significantly different from the sweeping and debris flow, and water and sediment flow in a dense and integrated manner. The gravel has very large kinetic energy.
[0004]
For this reason, when a gravel in a debris flow collides with a structure such as a sabo dam installed in a river in order to prevent a sediment disaster, this structure receives a very large impact force.
[0005]
Conventionally, as a sabo dam, for example, a concrete gravity sabo dam as shown in FIG. 5 has been generally constructed. This gravitational sabo dam receives the impact force generated by the impact of gravel in the debris flow by its huge weight and keeps it stable.
[0006]
However, most of the concrete sabo dams are so-called impervious types that dam up even small gravel and mud and store them completely. In addition, while it can completely store even small gravel and muddy water, it has a major disadvantage that it quickly accumulates earth and sand and loses its function as a sabo dam in a short period of time. In addition, the embankment has the disadvantage of requiring huge costs and days.
[0007]
By the way, recently, natural sediment transport downstream is an indispensable event to prevent river and coastal erosion, and in the same way for fish and other ecosystems, normal sediment inflow downstream. There has been a clear idea that should be preserved.
[0008]
For this reason, a permeable sabo dam has been proposed that blocks only large gravel from the flowing sediment and allows small gravels and muddy water to pass downstream. In particular, various types of steel permeable sabo dams have been proposed. Many have been proposed and put into practical use.
[0009]
For example, in Japanese Patent Application Laid-Open No. 54-115520, as shown in FIG. 6A which is a perspective view thereof and FIG. A transmission type sabo dam 12 has been proposed.
[0010]
JP-A-57-29717 proposes a transmission type sabo dam 15 having a main frame 13 and struts 14 as shown in FIG.
These sabo dams 12 and 15 both counteract the impact force generated by the impact of gravel in the debris flow by utilizing the strength of the steel pipe.
[0011]
It should be noted that sediment transport by normal sweep and sediment flow is sufficiently ensured because sufficient gaps are provided between the steel pipes.
Other examples of such transmission-type sabo dams are disclosed in Japanese Patent Application Laid-Open No. 2000-186318 and Japanese Patent Application Laid-Open No. 11-323883.
[0012]
Further, in Japanese Patent Laid-Open No. 62-288209, a rubber cushioning material shown in FIG. 8 (b) is a perspective view on the upstream side of the sabo dam 16 as shown in FIG. 8 (a) which is a side view thereof. An invention has been proposed in which 17 is provided to mitigate the impact force generated by the collision of gravel in a debris flow.
[0013]
[Problems to be solved by the invention]
However, the sabo dam proposed by Japanese Patent Application Laid-Open Nos. 54-115520 and 57-29717 is inevitably required for each steel pipe in order to sufficiently withstand the impact force generated by the collision of gravel in the debris flow. There is a problem that the size becomes large and the construction cost increases.
[0014]
Further, the rubber cushioning material 9 disclosed in Japanese Patent Application Laid-Open No. 62-288209 becomes expensive in order to ensure resistance to weathering and further durability against gravel, and is not practically applicable. is the current situation.
[0015]
The present invention has been made to solve the above problems, and has a large resistance to debris flow, especially when colliding with boulders, and does not impede the sediment transport action downstream of the river, with a shorter construction period. And it aims at providing the transmission type dam unit and transmission type dam which can be constructed | assembled at low cost.
[0016]
[Means for Solving the Problems]
The transmission type dam unit according to claim 1 has a gravity structure and a support structure supporting the gravity structure arranged on a concrete foundation, and the gravity structure is placed in a metal container. The support structure is formed in a plane triangle shape from a plurality of frame members, a top plate is attached to the upper end, and the downstream side of the river. It is characterized by being arranged in .
[0017]
A transmission type dam unit according to claim 2 is characterized in that, in the transmission type dam unit according to claim 1, sand is filled as a filling material in a metal container.
[0018]
The container in this case is made of steel plate, other metal plate other than steel plate, cloth bag reinforced with metal plate, etc., steel pipe with large diameter, steel plate cell (steel shell), or steel sheet pile. It may be what was done.
[0019]
The transmission type dam unit according to claim 3 is the transmission type dam unit according to claim 1 or 2, wherein the support structure is upstream from a plurality of columns and a plurality of horizontal members and diagonal members installed between the columns. It is formed in the shape of an inverted triangle with the side as the base of a triangle.
[0021]
A transmission type dam unit according to a fourth aspect is characterized in that a plurality of transmission type dam units according to the first, second or third aspect are installed at predetermined intervals in a river.
[0022]
As an example of the arrangement of the transmission type dam unit in this case, for example, two or three adjacent units are set as one set, and this is arranged at predetermined intervals in the width direction of the river (direction crossing the river) or in the width direction of the river. It may be arranged in a staggered manner.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 of the Invention
1 and 2 show one embodiment of a transmission type dam unit and a transmission type dam according to the present invention. In the figure, a gravity type structure 2 and a support structure 3 are arranged on a concrete foundation 1, respectively. Thus, a transmission type dam unit 4 is constructed.
[0024]
Further, a plurality of transmission type dam units 4 are provided in the river at predetermined intervals in the width direction (crossing the river), and the gravity structure 2 of each transmission type dam unit 4 is provided upstream of the river. The transmission type dam 5 is constructed by arranging the bodies 3 so as to be positioned on the downstream side.
[0025]
The foundation 1 has sufficient width, depth, thickness, and sufficient weight as the foundation of the gravity structure 2 and the support structure 3, and is constructed in a rectangular parallelepiped shape from concrete, most of which is embedded in the bottom of the river Has been.
[0026]
The foundation 1 is not necessarily a concrete structure as long as the foundation 1 has a structure that can reliably transmit the load from the gravity structure 2 and the support structure 3 to the ground. It may have a structure in which gravel is packed in a car body.
[0027]
The gravitational structure 2 is constructed in a cylindrical shape by filling sand as a filling material 7 in a cylindrical container 6, and is composed mainly of gravel in the debris flow by its own weight together with the concrete foundation 1 and the support structure 3. It works to relieve the large impact force when it is blocked and a huge gravel collides, and its outer diameter and height are the size of the gravel contained in the debris flow assumed at the installation site. Etc. are determined as appropriate. The gravitational structure 2 may have a wall shape in addition to the columnar shape.
[0028]
The container 6 is a metal outer shell, sufficiently withstands the hoop stress (circumferential tensile stress) due to the filled padding material 7, and the impact force when a debris flow collides with a large gravel in the debris flow. Is made of a material that can be relaxed by plastic deformation.
[0029]
Accordingly, it is desirable that the container 6 does not leak the filling material 7 and can be easily plastically deformed at the time of collision of gravel in the debris flow to mitigate the impact caused by the debris flow. It is formed from the steel plate etc. which have.
[0030]
The gravity structure 2 thus constructed is built on a concrete foundation 1 with its lower end buried in the concrete of the foundation 1 to a predetermined depth. The upper end portion of the gravity structure 2 is covered with a concrete top lid 8 so that the filling material 7 does not flow out in a debris flow.
[0031]
The container 6 does not necessarily need to be made of a steel plate as long as it does not leak the filling material 7 as the outer shell of the gravitational structure 2 and can reduce the impact at the time of gravel collision in the debris flow. It may be formed from a metal bag other than a steel plate or a cloth bag reinforced with a metal material.
[0032]
Further, the container 6 does not have to have a cylindrical shape, and may have a shape other than the cylindrical shape such as a rectangular tube shape according to the shape of the gravity structure 2. If there is, only the tensile hoop stress is received, so that the size can be reduced as necessary.
[0033]
Further, the upper lid 8 is not necessarily made of concrete, and may be made of a material other than concrete, for example, steel, other metal, or resin, or may not be provided with an upper lid.
[0034]
The support structure 3 is a frame structure that resists debris flow and sedimentation pressure acting on the gravitational structure 2. The support structure 3 has a triangular shape in a plan view, and has an upstream side on the downstream side of the gravitational structure 2. They are arranged in an inverted triangle shape with the base of the triangle.
[0035]
Further, the support structure 3 is constructed with a pillar 3a at a position corresponding to each apex of the triangle, and a plurality of horizontal members 3b and, if necessary, a plurality of diagonal members 3c are bridged between the three pillars 3a, 3a. Is constructed to a height equivalent to that of the container 3, and a concrete top plate 3 d is installed at the upper end.
[0036]
The struts 3a, the horizontal members 3b, and the diagonal members 3c are all formed from steel pipes, shaped steels, reinforcing bars, or the like, and the members are joined to each other by appropriate joining means such as welding or bolt fastening.
[0037]
The support structure 3 constructed in this manner is built on the concrete foundation 1 with the lower end embedded in the concrete of the foundation 1 to a predetermined depth in the same manner as the container 6. 9 are integrally connected.
[0038]
In this case, the connecting member 9 is formed of a steel pipe or the like in the same manner as the support column 3a, and a plurality of connecting members 9 are installed at predetermined intervals in the vertical direction of these members between the housing 6 and the two support columns 3a and 3a. Yes.
[0039]
As described above, since the support structure 3 is constructed as a triangular frame structure in a plan view, the resistance to the small and medium gravel and the muddy water passing between the gravitational structures 2 and 2 is extremely small, and the upper end Since the concrete top plate 3d is installed in the section, even if boulders get over the gravity structure 2, they will not directly collide with the frame material such as the pillar 3a. There is no concern that excessive bending stress or shearing force will act on these members to cause local buckling.
[0040]
Therefore, the screen effect of the support structure 3 can be maintained for a longer period of time, and each member cross section of the column 3a, the horizontal member 3b, and the diagonal member 3c can be made as small as possible to provide an economical support structure.
[0041]
Note that the support structure 3 is not necessarily required to be a structure in which steel pipes are combined as long as the support structure 3 can reliably support the gravity structure 2 , and may be a structure of another structure method.
[0042]
As the filling material 7, a material having the most suitable strength is used in consideration of the plastic deformation ability of the container 6, and sand is mainly used. Since the container 6 is filled with sand as the filling material 7, it absorbs the impact force when the gravel collides with the container 6 due to friction between sand and crushing of the sand, and the load due to the collision of the gravel. By converting (impact load) into a static force, the load can be transmitted to the support structure 3 arranged on the downstream side of the container 6.
[0043]
In addition to the sand, for example, crushed stone is also used as the filling material 7, sandy soil-based construction residue and waste materials, various steelmaking slag and cullet materials, viscous soil-based construction residue, soil cement and air bubbles Materials such as mortar, and materials such as waste tires and rubber can also be used. Further, depending on the installation conditions, various wastes can be used as filling materials.
[0044]
Three transmission dam units 4 constructed in this way are arranged in a row in the river in the width direction (the direction crossing the river), that is, in a direction substantially perpendicular to the direction of the flow of debris flow, Each transmission type dam unit 4 is arranged such that the gravity structure 2 is located on the upstream side of the river and the support structure 3 is located on the downstream side.
[0045]
Furthermore, a predetermined distance L is provided between the gravity-type structures 2 and 2 of the adjacent transmission type dam units 4 and 4 so as to secure a distance such that boulders included in the debris flow assumed in the river do not pass directly. Adjacent transmission dam units 4 and 4 are provided respectively. Thus, the transmission type dam 5 is constructed from the three transmission type dam units 4.
[0046]
The transmission dam units 4 are arranged in a necessary number according to the river width of the river, and may be arranged in a plurality of rows according to the assumed scale of debris flow.
In general, since conventional transmission type dams need to have a structure that can resist debris flow fluid force, sedimentation pressure, and the like, steel pipe members are assembled in a bowl shape in order to reduce the structural members. However, if the shape is simply a bowl, there is a risk that a very large impact force of the debris flow will act directly and break down at an early stage, and the structural member has to be enlarged.
[0047]
On the other hand, in the transmission type dam unit 4 of the present embodiment, the gravitational structure 2 is arranged on the upstream side of the support structure 3 to prevent the debris flow from directly colliding with the support structure 3. Therefore, the structural member can be made small.
[0048]
Embodiment 2 of the Invention
FIG. 3 shows another embodiment of the transmission type dam unit and the transmission type dam according to the present invention, and the description will be given only for the parts different from the first embodiment, and the common parts are the same. Reference numerals are omitted.
[0049]
In this example, two columnar gravitational structures 2 are arranged on the concrete foundation 1 in particular, and are arranged side by side in the width direction of the river at predetermined intervals, and between the gravitational structures 2 and 2 on the downstream side thereof. One supporting structure 3 for supporting them is disposed, and two supporting structures 3 are supported by one supporting structure 3.
[0050]
According to this example, the sediment transportability can be improved as compared with the example of the first embodiment, thereby preventing the sediment transport function of the river and the continuity of the ecosystem from being disturbed.
[0051]
Embodiment 3 of the Invention
FIG. 4 shows another embodiment of the transmission type dam unit and the transmission type dam according to the present invention, and the description will be given only for the parts different from those of the first and second embodiments. Are omitted with the same reference numerals.
[0052]
In this example, in particular, two columnar gravitational structures 2 are arranged on the concrete foundation 1 so as to overlap with each other along the flow direction of the river, and one support structure 3 is provided downstream to support them. It is arranged.
[0053]
According to this example, both the thickness and the own weight of the gravitational structure 2 are doubled as compared with the examples of the first and second embodiments. Therefore, the impact at the time of the collision of gravel due to the shear deformation of the filling material 7 is reduced. The effect of buffering becomes larger, and this has the effect of reducing the weight of the support structure 3.
[0054]
【The invention's effect】
This invention is as having demonstrated above, and there exists an effect listed below.
(1) The gravity structure is constructed by filling a circular or rectangular container with a filling material such as sand or crushed stone, and the support structure for supporting the structure is constructed from a steel pipe or the like as a framework structure. Since none of them is a special structure, it can be constructed in a short construction period and at a low cost.
(2) Since the gravity structure is located upstream of the river, the debris flow is extremely resistant to impact forces, especially when boulders collide, and the flow speed of boulders in the debris flow is reliably reduced. Can do.
[0055]
(3) In addition, since a support structure constructed in an inverted triangle shape in a plane is arranged on the downstream side, the resistance to small and medium gravel and muddy water is small. There is no worry of hindering transportation.
(4) In addition, the support structure is constructed as a framework structure, so that even if boulders get over the gravitational structure, it is constructed in a structure that does not generate large bending or tensile force on each member. A simple cross-section design is possible.
[Brief description of the drawings]
FIG. 1 is a perspective view of a transmission dam unit and a transmission dam according to the present invention.
FIG. 2 shows a transmission dam unit according to the present invention, in which (a) is a plan view and (b) is a side view.
FIG. 3 is a perspective view showing a transmission dam unit and a transmission dam according to the present invention.
FIG. 4 is a perspective view showing a transmission dam unit and a transmission dam according to the present invention.
FIG. 5 is a perspective view showing an example of a conventional impermeable sabo dam.
FIG. 6 shows an example of a conventional transmission-type sabo dam, where (a) is a perspective view and (b) is a side view.
FIG. 7 is a side view showing an example of a conventional transmission type sabo dam.
FIG. 8 shows an example of a conventional impermeable sabo dam, where (a) is a cross-sectional view and (b) is a perspective view.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Concrete foundation 2 Gravity type structure 3 Support structure 3a Support | pillar 3b Horizontal material 3c Diagonal material 3d Top plate 4 Transmission type dam unit 5 Transmission type dam 6 Container 7 Filling material 8 Top lid 9 Connecting material

Claims (4)

A gravitational structure and a support structure that supports the gravitational structure are arranged on a concrete foundation, the gravitational structure is formed by filling a metal container with filling material, and a river The support structure is formed in a plane triangle shape from a plurality of shaft assemblies, a top plate is attached to the upper end portion, and the transmission structure is disposed on the downstream side of the river. Type dam unit. The transmission type dam unit according to claim 1, wherein sand is filled as a filling material in a metal container. The support structure is formed in an inverted triangle shape having a base of a triangle on the upstream side from a plurality of columns and a plurality of horizontal members and diagonal members installed between the columns. The transmission type dam unit according to 2 . A transmission dam comprising a plurality of transmission dam units according to claim 1, 2 or 3 arranged at predetermined intervals in a river.

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