Open type dam

Abstract

To provide an open type dam allowing a sediment adjustment function corresponding to a scale of the dam using weir effect by auxiliary dams to be realized, and insuring structural stability while securing reservoir amount and capturing amount.SOLUTION: A dam body 2 of an open type dam 1 is provided with capturing bodies 9 between left and right side walls 8, and the capturing body 9 is formed by arranging a plurality of capturing units 12 parallelly in a river width direction and is provided with an oblique duckboard part 27 and a horizontal duckboard part 28 between left and right support frame bodies 13, wherein lower ends of the left and right support frames are fixed on a horizontally buried reinforcement body 35 extended from the dam body 22 to auxiliary dams 3 in a concrete base 4, the auxiliary dam 3 is provided a dam part 52 arranged between the left and right walls 51, and slits 56 are formed in the dam part 52. A water passage width W of the dam body 22 is equal to an overflow width w (slit width×slit number) of the auxiliary dam 3, and a height H of an opening 30 from the concrete base 4 to a horizontal frame 18 of the dam body 22 is generally equal to a height h of the dam part 52 of the auxiliary dam 3.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a permeable dam, and in particular to a permeable dam to be installed in a sweeping section of a river where sediment movement is active during floods. Here, the sweeping section refers to an area downstream of the river where large-grained sediment and driftwood flow separately with a gentle gradient of 1 / 30 or less. [Background technology]

[0002] Conventionally, impermeable dams made of concrete have been installed in the sweeping section (see Patent Document 1). Impermeable dams have the effect of reducing the sweeping force by filling them with sand, which makes the upstream riverbed gradient gentler.

[0003] Furthermore, there is a conventional concrete slit dam that utilizes damming to store sediment in a pocket upstream of the dam (see Patent Document 2).

[0004] Furthermore, horizontal beam dams have been developed to solve the problems of conventional concrete slit dams (see Patent Documents 3 to 6). In addition, the actual structure of a horizontal beam dam requires a high degree of processing, which is costly, and because the capture body is processed to be detachable using steel pipes, the opening width between the steel pipes is wide, making it impossible to form gaps that can capture the sand and gravel flowing down in the sweeping section. For this reason, this dam is intended for use in areas where debris flow accumulates.

[0005] Furthermore, because the sediment is placed on the overhanging part of the trapping body, the trapping body must support the weight of the soil, and so the higher the dam height, the larger the components used. Also, since it is installed in the sweeping section, the action of hydrostatic pressure is large, and it is difficult to ensure stability with a structure with a small self-weight such as a permeable dam, so only small-scale facilities can be used. As such, this dam has limitations in its range of application and structure, making it difficult to apply to sweeping sections. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2004-316081 A [Patent Document 2] JP 2003-138544 A [Patent Document 3] JP 2006-328658 A [Patent Document 4] JP 2009-243196 A [Patent Document 5] JP 2009-270257 A [Patent Document 6] JP 2009-270333 A Summary of the Invention [Problem to be solved by the invention]

[0007] Impermeable concrete dams (see Patent Document 1) can reduce the tractive force by filling them with sand, as the upstream riverbed gradient becomes gentler, but they still supply a large amount of sediment downstream of the dam, making them less effective at preventing sediment flooding caused by rising riverbed.

[0008] Concrete slit dams (Patent Document 2) store sediment during the flood period, but in the later stages of the flood, the stored sediment moves again, supplying sediment downstream of the dam and therefore being less effective in suppressing riverbed rise.

[0009] Furthermore, while the slits have a damming effect before and after the peak of the flood, the damming effect is small when the flow rate is low, so there is a drawback in that the regulating function of the dam itself is difficult to achieve given the size of the dam.

[0010] Horizontal beam dams (see Patent Documents 3 to 6) are expensive because of the high degree of fabrication required for the actual structure, and because the steel pipes are used for the capture body and are fabricated to be detachable, the opening width between the steel pipes is wide, making it impossible to form gaps that can capture the sand and gravel flowing down in the sweeping section. For this reason, the scope of application of these dams is the accumulation section of debris flow.

[0011] Furthermore, because the sediment is placed on the overhanging part of the trapping body, the trapping body must support the weight of the soil, and so the higher the dam height, the larger the components used. Also, since it is installed in the sweeping section, the action of hydrostatic pressure is large, and it is difficult to ensure stability with a structure with a small self-weight such as a permeable dam, so only small-scale facilities can be used. As such, this dam has limitations in its range of application and structure, making it difficult to apply to sweeping sections.

[0012] The present invention aims to solve the problems associated with conventional dams as described above, and has as its objective the realization of a permeable dam which aims to ensure the amount of sediment storage and capture appropriate to the size of the dam while also guaranteeing structural stability by efficiently utilizing the dam's raising effect. [Means for solving the problem]

[0013] In order to solve the above problems, the present invention provides a permeable dam to be installed in a river sweeping section, comprising a main dam constructed on a concrete foundation and a sub-dam constructed downstream of the main dam, the main dam having left and right side walls and a capture body provided between the left and right side walls, the capture body having a support frame and a sieve section having a plurality of capture rods disposed at intervals between the support frame, the sieve section having an inclined sieve section and a horizontal sieve section, and a horizontal sieve section is provided in the concrete foundation from the main dam to a position directly below the sub-dam. The present invention provides a permeable dam characterized in that a horizontal buried reinforcement body is buried so as to extend along the longitudinal axis of the main dam, the secondary dam has left and right side walls provided on a concrete base and a dam section provided between the left and right side walls, is substantially concave-shaped when viewed from the front upstream, a slit is formed from the top of the dam section toward the bottom, the water passage width which is the width between the left and right side walls of the main dam is the same as the overflow width which is the width between the left and right side walls of the secondary dam, and the height from the concrete base to the horizontal frame of the main dam is substantially the same as the height of the dam section of the secondary dam.

[0014] In order to solve the above problems, the present invention provides a permeable dam to be installed in a sweeping section of a river, comprising a main bank constructed on a concrete foundation and a sub-bank constructed downstream of the main bank, the main bank having left and right side walls and a capture body provided between the left and right side walls, the capture body being made up of a plurality of capture units arranged side by side in the river width direction, the capture unit having left and right support frames and an inclined sieve section and a horizontal sieve section in which a plurality of capture rods are arranged at intervals between the left and right support frames, the lower ends of the left and right support frames being disposed within the concrete foundation and adjacent to the main bank. The present invention provides a permeable dam characterized in that the main dam is fixed to a horizontally buried reinforcement buried so as to extend horizontally from the main dam to the position of the secondary dam, the secondary dam has left and right side walls provided on a concrete base and a dam section provided between the left and right side walls and is approximately concave-shaped when viewed from the front from the upstream side, a slit is formed from the top of the dam section toward downwards, the water passage width which is the width between the left and right side walls of the main dam is the same as the overflow width which is the width between the left and right side walls of the secondary dam, and the height from the concrete base to the horizontal frame of the main dam is approximately the same as the height of the dam section of the secondary dam.

[0015] In order to solve the above-mentioned problems, the present invention provides a permeable dam to be installed in a sweeping section of a river, comprising a main bank constructed on a concrete foundation and a sub-bank constructed downstream of the main bank, the main bank comprising left and right side walls provided on the concrete foundation and a capture body provided between the left and right side walls, the capture body being composed of a plurality of capture units arranged side by side in the river width direction, the capture unit comprising left and right support frames, and an inclined sieve section and a horizontal sieve section in which a plurality of capture rods are arranged at intervals between the left and right support frames, the support frame comprising an inclined frame, a horizontal frame extending horizontally from a lower portion of the inclined frame to the upstream side, and an inclined frame support pillar and a horizontal frame support pillar which support the inclined frame and the horizontal frame respectively on the concrete foundation, the support frame being composed of adjacent The inclined frame support pillars and vertical frame support pillars of the capture unit are each supported by penetrating a concrete body that is oval-shaped in a plan view, and their lower ends are fixed to a horizontally buried reinforcement body buried in the concrete foundation so as to extend horizontally from the main bank to the position of the secondary bank, the secondary bank has left and right side walls provided on the concrete foundation and a dam section provided between the left and right side walls, is approximately concave-shaped when viewed from the front from the upstream side, a slit is formed from the top of the dam section extending downward, the water passage width which is the width between the left and right side walls of the main bank is the same as the overflow width which is the width between the left and right side walls of the secondary bank, and the height from the concrete foundation to the horizontal frame of the main bank is approximately the same as the height of the dam section of the secondary bank.

[0016] The horizontal frame support columns are preferably configured as vertical or inclined columns.

[0017] It is preferable that a cross rod is installed between the left and right horizontal frames, and lifting rods are installed between the cross rod and each of the left and right horizontal frame support pillars.

[0018] It is preferable that a cross rod is installed between the left and right horizontal frames, and that the left and right horizontal frames are provided with triangular side frames with the horizontal frames as their bases, and that a suspension rod is installed between the tops of the left and right triangular side frames and the cross rod.

[0019] It is preferable that vertical support frames be fixed to the left and right horizontal frames with their tips facing downwards at a distance from the concrete base, and that capture rods be erected between the left and right vertical support frames at a distance in the vertical direction, and that a vertical slat section be provided.

[0020] It is preferable that the inclined frame support pillars and the horizontal frame support pillars are each protected by a steel protective cylinder fitted thereto.

[0021] It is preferable that the inclined frame support pillars and the horizontal frame support pillars are each configured to penetrate the oval-shaped concrete body on the concrete foundation. Effect of the Invention

[0022] In the permeable dam of the present invention, the main dam and the secondary dam function synergistically to effectively provide a sediment control function by allowing sediment contained in the river flow to accumulate naturally little by little upstream of the main dam.

[0023] In addition, the lower end of the support frame supporting the sill part of the main embankment is fixed to a horizontally buried reinforcement body extending within the concrete base from directly below the main embankment to directly below the secondary embankment, providing great strength against the water pressure of the river flow and the pressure of the contained soil and sand, and ensuring structural stability. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1A is a diagram for explaining the function of a dam having no secondary dam as in the present invention, and FIG. 1B is a diagram for explaining the overall configuration and function of a permeable dam according to the present invention. [Diagram 2] FIG. 1 is a diagram explaining the overall structure and operation of a permeable dam according to the present invention, in which (a) shows a state in which sediment has accumulated to a height slightly above the opening of the dam, and (b) shows a state in which sediment has accumulated even higher. [Diagram 3] FIG. 1 is a diagram for explaining a first embodiment of a permeable dam according to the present invention, in which (a) is a front view of a main dam, (b) is a front view of a secondary dam, and (c) is a perspective view of the secondary dam. [Figure 4] 1A and 1B are diagrams illustrating the capture unit of the main bank in Example 1, where (a) is a front view and (b) is a vertical cross-sectional view seen from the side. [Diagram 5] FIG. 1 is a diagram for explaining Example 1, in which (a) is a partial cross-sectional view (cross-section of the concrete base) of the entire permeable dam as viewed from the side, and (b) is a BB cross-sectional view of (a). [Figure 6] 5A and 5B are diagrams illustrating a modified example of the capture unit of the first embodiment, in which (a) is a front view and (b) is a vertical sectional view seen from the side. [Figure 7] 1A and 1B are diagrams for explaining the function of the permeable dam of Example 1, where (a) is a diagram for explaining the problem when there is no horizontal sieve section, (b) is a diagram for explaining the effect of Example 1 in which a horizontal sieve section is provided, and (c) is a diagram for explaining the effect when a vertical sieve section is provided. [Figure 8] 1A and 1B are diagrams illustrating a second and a third embodiment of a permeable dam according to the present invention, respectively. [Figure 9] 11A and 11B are diagrams for explaining a fourth embodiment of the permeable dam according to the present invention, in which (a) is a front view of the dam, and (b) is a cross-sectional view seen in the BB direction of (a). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] A form for carrying out a permeable dam according to the present invention will be described below based on an embodiment with reference to the drawings. In the description of the embodiment, the front side as viewed from the upstream side of the river is referred to as the front side, the left and right sides in the river width direction are referred to as the left and right sides, and the side side as viewed from the lateral direction (side direction) of the river is referred to as the side side. EXAMPLES

[0026] Example 1 A first embodiment of a permeable dam according to the present invention will be described with reference to Fig. 1 to Fig. 7. As shown in Fig. 1(b), the basic configuration of a permeable dam 1 according to the present invention comprises a main dam 2 installed on the upstream side of a river, a secondary dam 3 installed on the downstream side, and a concrete base 4 that serves as a base for the main dam 2 and the secondary dam 3. The concrete base 4 is constructed on the river bottom so that its upper surface is horizontal.

[0027] Main embankment: As shown in Figure 3(a), the main embankment 2 has left and right side walls 8 standing on a concrete base 4, and a trap-like catcher 9 arranged between the left and right side walls 8 to catch sand and gravel.

[0028] There are various possible structures for the lattice-like capture body 9, but in Example 1, the overall structure is shown in Figure 3(a), and is composed of multiple capture units 12 arranged in a row in the direction of the river width.

[0029] As shown in FIGS. 4( a ) and 4 ( b ), the capture unit 12 includes left and right support frames 13 and a drainage section 14 provided between the left and right support frames 13 .

[0030] The left and right support frames 13 each include an inclined frame 17, a horizontal frame 18 extending horizontally upstream from the lower part of the inclined frame 17, an inclined frame support pillar 19 that supports the inclined frame 17 from the downstream side, and a horizontal frame support pillar 20 that supports the horizontal frame 18 on the concrete foundation 4.

[0031] In this embodiment 1, as shown in FIG. 4(b), the horizontal frame support pillars 20 are vertical pillars that support the upstream end and downstream end of the horizontal frame 18 on the concrete base 4, respectively.

[0032] A horizontal rod 24 is installed between the left and right horizontal frames 18. As shown in Fig. 4(a), an inclined lifting support rod 25 is disposed between the horizontal rod 24 and each of the left and right horizontal frame support pillars 20. By providing such lifting support rods 25, the horizontal frame 18 is supported from below.

[0033] The drain section 14 includes an inclined drain section 27 and a horizontal drain section 28. The inclined drain section 27 includes a plurality of capture rods 29 horizontally installed at regular intervals in the vertical direction between the left and right inclined frames 17.

[0034] The horizontal grate section 28 is equipped with a plurality of capture rods 29 horizontally installed at regular intervals between the left and right horizontal frames 18. Between the horizontal grate section 28 and the concrete base 4 is a water passage opening 30 through which river water flows.

[0035] The inclined frame 17, horizontal frame 18, inclined frame support pillars 19, horizontal frame support pillars 20, capture rods 29, etc. may all be made of steel, such as steel pipes, shaped steel, etc. However, since it is difficult to connect steel pipes to each other, it is necessary to use steel plates or shaped steel appropriately for the connections.

[0036] In the capture unit 12 constructed in this manner, the grate section 14 functions as the gravel capture body 9, and the space between the grate section 14 and the concrete base 4 functions as the water passage opening 30, as described above. A plurality of capture units 12 constructed in this manner are arranged in a row in the river width direction, as described above, to construct the main embankment 2 shown in Figure 3(a).

[0037] In a structure in which multiple capture units 12 are arranged in a row in the river width direction, the lower parts of the support frames 13 on adjacent sides of adjacent capture units 12 are inserted so as to penetrate in the vertical direction into an oval-shaped concrete body 34 (see Figure 5(b)) that has been poured onto the concrete base 4 and has an oval shape when viewed horizontally.

[0038] Specifically, the inclined frame support pillars 19 and the horizontal frame support pillars 20 are inserted so as to penetrate the oval concrete body 34, as shown in Figs. 4(a) and 4(b) and Figs. 5(a) and 5(b).

[0039] The height of the oval concrete body 34 is the height from the concrete base 4 to the bottom end of the drainage slat portion 14, which is approximately the same as the vertical dimension between the concrete base 4 and the horizontal drainage slat portion 28, i.e., the water passage opening 30.

[0040] With this construction, the oval concrete body 34 protects the support frame 13 against the pressure of the river water flowing through the water passage opening 30 and the pressure of earth and sand.

[0041] The upstream and downstream faces of the oval concrete body 34 are curved as shown in Fig. 5(b), allowing the river water to flow smoothly and being less susceptible to water pressure, thus reducing damage. Also, the occurrence of vortexes and cavitation in the main embankment 2 is reduced, preventing the river flow from being obstructed.

[0042] The inclined frame support pillars 19 and the horizontal frame support pillars 20 are each configured so that their lower ends extend from the oval concrete body 34 further into the concrete foundation 4, as shown in Figs.

[0043] 4 and 5, the lower ends of the respective members are fixed to horizontally embedded reinforcement members 35 embedded horizontally in the concrete base 4. The horizontally embedded reinforcement members 35 are made of H-shaped steel or the like.

[0044] As shown in Figure 5, the left and right horizontal buried reinforcements 35, which correspond to the left and right support frames 13 of each capture unit 12, are buried within the concrete foundation 4, extending horizontally from just below the main embankment 2 to just below the secondary embankment 3, crawling from upstream to downstream.

[0045] As the main embankment 2 is constructed as described above, it has structural strength, and the grating section 14 has the strength and durability to withstand water pressure and earth pressure caused by river water flow and accumulated sediment.

[0046] In particular, in the permeable dam 1 of the present invention, the horizontally buried reinforcement members 35 buried horizontally in the concrete foundation 4 are configured so as to extend horizontally from directly below the main dam 2 to directly below the secondary dam 3.

[0047] Furthermore, the inclined frame support pillars 19 and the horizontal frame support pillars 20 are fixed to the horizontal buried reinforcement body 35, and the inclined frame support pillars 19 and the horizontal frame support pillars 20 support the inclined frame 17 and the horizontal frame 18. Therefore, even when the river flow is strong, such as during flooding, the structure has great structural strength against river water flow and gravel.

[0048] In addition, the horizontally buried reinforcement body 35 buried horizontally in the concrete foundation 4 may be configured to have multiple bodies, such as two bodies, provided in the depth direction of the concrete foundation 4 for each support frame 13 rather than one body.

[0049] With this construction, the capture body 9 of the main embankment 2 has the strength to withstand downstream pressure exerted on it by the river's water flow, sand and gravel, etc., or the moment applied to it as if it were being lifted upward and downstream.

[0050] Conventional open dams have a light weight, which makes them disadvantageous in terms of sliding (the phenomenon in which the main dam moves downstream relative to the concrete base 4 due to the pressure of accumulated sediment from upstream and still water). However, the horizontally buried reinforcement 35 does not directly connect the main dam 2 and the secondary dam 3, but is buried horizontally within the concrete base 4 so as to extend between directly below the main dam 2 and the secondary dam 3. As a result, the main dam 2 and the secondary dam 3 are indirectly integrated, and can resist sliding as a whole. From this point of view as well, the strength is increased.

[0051] Variations of the capture unit: 6(a) and 6(b), a modified example of the capturing unit 12 will be described. The modified capturing unit 37 has substantially the same configuration as the above-described capturing unit 12, so the following description will focus on the different configuration.

[0052] In this modified capture unit 37, like the capture unit 12, the left and right support frames 13 each have an inclined frame 17 and a horizontal frame 18, and the inclined frame 17 is supported on the concrete foundation 4 by inclined frame support pillars 19.

[0053] However, in the modified capture unit 37, the inclined frame 17 extends through the oval concrete body 34 into the concrete foundation 4, as shown in Figure 6(b), and is fixed to a horizontally buried reinforcement body 35 for reinforcing the concrete foundation 4.

[0054] A horizontal frame support pillar 38 is provided on the upstream end of the horizontal frame 18 to support the horizontal frame 18 on the concrete foundation 4. The horizontal frame support pillar 38 extends downward toward the lower end of the downstream inclined frame 17 through the oval concrete body 34 into the concrete foundation 4, and is fixed to the inclined frame 17 and the horizontal buried reinforcement body 35 for reinforcing the concrete foundation 4.

[0055] A horizontal rod 39 is installed horizontally between the center parts of the left and right horizontal frames 18 (see FIG. 6(a)). Furthermore, a triangular frame 40 is provided on the horizontal frame 18, the triangular frame 40 having the horizontal frame 18 as its base when viewed from the side (see FIG. 6(b)).

[0056] As shown in Figures 6(a) and 6(b), the hanging support rods 44 are arranged at an angle to the tops 41 of the left and right triangular frames 40 and the horizontal rods 39 to form a truss structure. This truss structure allows the hanging support rods 44 to support the horizontal frame 18 from above, making the structure stronger.

[0057] Subplot: The secondary levee 3 will be described with reference to Figures 3(b) and (c) etc. The secondary levee 3 is constructed on the same concrete foundation 4 as the main levee 2. As shown in Figures 3(b) and (c), the secondary levee 3 has a weir section 52 formed integrally between left and right side walls 51, and is generally concave-shaped when viewed from the front from the upstream side.

[0058] The height to the upper ends of the left and right side walls 51 is lower than that of the main dam 2, but the side shape is approximately the same. The height of the weir section 52 is lower than that of the left and right side walls 51, and an overflow section 53 is formed that is surrounded by the left and right side walls 51 and the upper ends of the weir section 52. The horizontal width of the overflow section 53, i.e., the overflow width w (see Figure 3(b)), is the same as the water passage width W of the main dam 2 (see Figure 3(a)).

[0059] A plurality of slits 56 are formed in the dam portion 52. As shown in Figures 3(b) and (c), the slits 56 open at the top 57 of the dam portion 52 and extend downward to the lower end of the dam portion 52, i.e., to the surface of the concrete base 4.

[0060] The width d of the slit 56 in the secondary embankment 3 (the total of the slits 56 if there are multiple slits 56) divided by the water passage width W of the main embankment 2 is called the opening rate, and in the present invention, the opening rate is set to approximately 10% of W.

[0061] As will be described later, the permeable dam of the present invention has a sediment control function in which the main dam and the secondary dam function synergistically to allow sediment contained in the river flow to accumulate naturally little by little upstream of the main dam.

[0062] Effect: We will now explain the function of the permeable dam 1 of the present invention, constructed as described above, focusing in particular on the synergistic functions of the main dam 2 and the secondary dam 3. Conventionally, the secondary dam 3 has been provided as an auxiliary structure to the main dam, such as to supplementarily capture sand and gravel that cannot be captured by the main dam.

[0063] However, in the present invention, contrary to the conventional thinking, secondary dyke 3 is not merely auxiliary to main dyke 2, but is rather established to play a leading role in ensuring that main dyke 2 operates effectively, thereby enabling main dyke 2 and secondary dyke 3 to exert a synergistic function.

[0064] To this end, the respective configurations and relational configurations of the main embankment 2 and the secondary embankment 3 are as described above, and in the present invention, a configuration is adopted in which the numerical values, etc. of the configuration of each part of the secondary embankment 3 are limited as described above in relation to the configuration of the main embankment 2.

[0065] The river flowing down the slope from upstream passes through the water passage opening 30 of the main levee 2 during sweeping and flows downstream (see Figure 1(a)). If the sediment contained in the river flow is captured little by little just before the upstream side of the main levee 2 and deposited, it can be removed by heavy machinery etc. when a certain amount of deposited sediment has formed, and the flow of sediment downstream can be reduced.

[0066] In this way, it is preferable that the sediment contained in the river flow be allowed to accumulate naturally little by little just before the upstream side of the dam 2 (this function is called the "sediment control function").

[0067] However, during sweeping, that is, during normal, relatively gentle, small to medium-sized flow rates, if there is only a main levee 2 and no secondary levee 3, as shown in Figure 1(a), the sediment contained in the river flow will pass through the water passage opening 30 of the main levee 22 along with the water flow and flow downstream, making it relatively difficult to achieve the sediment control function.

[0068] Therefore, in the permeable dam 1 according to the present invention, as shown in Figures 1(b), 2(a) and (b), a secondary dam 3 equipped with a slit 56 is installed downstream of the main dam 22. As mentioned above, the overflow width w of the secondary dam 3 is set to be the same as the water passage width W of the main dam 22. The height h of the weir section 52 of the secondary dam 3 is set to be approximately the same as the height H of the upper end of the water passage opening 30 of the main dam 22.

[0069] With the secondary levee 3 constructed in this way, when the river flow rate is small to medium, the flowing water of the river passes through the water passage opening 30 of the main levee 22, as shown in Figure 1(b). When the river flow rate is extremely low, the flowing water passes through the slits 56 of the secondary levee 3 and does not accumulate on the upstream side of the weir section 52.

[0070] By the way, through experiments etc., the inventor has discovered that when the opening rate is set to approximately 10% of W and the height h of the dam section 52 of the secondary dam 3 is set to approximately the same height as the height H of the upper end of the water passage opening 30 of the main dam 22, the permeable dam of the present invention can effectively exhibit a sediment control function.

[0071] During normal sweeping, some of the flowing water that passes through the water passage opening 30 of the main dam 22 passes through the slits 56 in the secondary dam 3 and flows downstream, as shown in Figure 1(b), while the other flowing water gradually accumulates on the upstream side of the weir section 52 of the secondary dam 3 and is dammed up to the top 57 of the weir section 52.

[0072] Since part of the river water flows through the slits 56 in the secondary embankment 3 and the overall flow velocity decreases, the sediment in the flowing water is less likely to be carried downstream by the river current and is gradually accumulated as sediment 63 near the water passage opening 30 of the main embankment 22, as shown in Figure 1(b).

[0073] 2(a), when the accumulated sediment 63 builds up to a height exceeding the upper end of the water passage opening 30, the sediment in the flowing water is captured by the inclined sieve section 27, and the flowing water that passes through the inclined sieve section 27 flows downstream beyond not only the slits 56 of the secondary dam 3 but also the weir section 52 (this is called overflow). Note that f1 is the water depth raised by the provision of the secondary dam 3, and f2 is the overflow water depth that exceeds the weir section 52 of the secondary dam 3.

[0074] In other words, the height h to the top 57 of the weir portion 52 of the secondary levee 3 and the height H to the upper end of the water passage opening 30 of the main levee 22 are approximately the same configuration, so when the secondary levee 3 is dammed up and exceeds the upper end of the water passage opening 30, as shown in Figure 2(a), some of the river water will flow downstream over the weir portion 52 of the secondary levee 3.

[0075] During sweeping, the flow velocity of the soil in the flowing water decreases, so that the soil sinks little by little before being carried downstream. As a result, the amount of soil that sinks decreases as it moves downstream. As a result, the tip of the soil 63 deposited on the main embankment 22 slopes upward from the downstream side to the upstream side, as shown in Figures 1(b) and 2(a), etc.

[0076] In other words, the sediment deposited in the water moves from upstream to downstream while maintaining the shape of the underwater angle of repose (the top of the sediment is called the sediment shoulder). When this sediment shoulder that was moving from upstream to downstream reaches the horizontal drain, its movement downstream is restricted.

[0077] As the sediment in the flowing water is further captured by the inclined grate section 27 from the state shown in Fig. 2(a), sediment deposits 63 are formed up to the top of the inclined grate as shown in Fig. 2(b). Even in this state, similar to the state shown in Fig. 2(a), the flowing water that has passed through the inclined grate section 27 flows downstream beyond not only the slits 56 of the secondary grate 3 but also the weir section 52 of the secondary grate 3.

[0078] Figure 7 shows a state in which sediment is gradually deposited in front of the upstream side of the main dam due to the sediment control function of the permeable dam 1, and the deposited sediment 63 has accumulated up to a height above the inclined cage section 27. If the capture body 9 of the main dam 22 were only the inclined cage section 27, as shown in Figure 7(a), the lower end of the inclined cage section 27 would come into contact with the sediment shoulder 64 of the deposited sediment 63 (the upper end of the slope).

[0079] In this state, the water pressure of the flowing water and the pressure of the sediment are applied from above upstream of the sediment shoulder 64 as shown by the arrows, and the disturbance of the water surface caused by water falling from the inclined grate section 27 pushes the tip of the accumulated sediment 63 downstream, causing the slope 66 to collapse, and the sediment flows downstream from the main embankment 22.

[0080] However, in the open dam 1 according to the present invention, a horizontal drainage sieve section 28 is provided, as shown in FIG. 7(b), so that a sediment shoulder 64 is formed at the upstream end of the horizontal drainage sieve section 28.

[0081] With this configuration, a space 65 is created downstream of the inclined surface 66 at the tip of the accumulated sediment 63, and even if the water pressure of the flowing water and the pressure of the sediment are applied from above as shown by the arrows from the sediment shoulder 64 upstream, the pressure is not applied directly to the accumulated sediment 63 so as to push it downstream, due to the existence of the space 65, so that the inclined surface 66 at the tip of the accumulated sediment 63 is less likely to collapse.

[0082] 7(c), if a vertical sieve section 68 hanging downward is provided at the upstream end of the horizontal sieve section 28, the sediment shoulder 64 will be located a little further upstream, creating a gap 70 between the upstream end of the horizontal sieve section 28 and the sediment shoulder 64, making the slope 66 less likely to collapse. Also, providing the vertical sieve section 68 hanging downward raises the position of the horizontal sieve, which has the effect of reducing the weight of soil placed on it.

[0083] The vertical sieve section 68 is constructed by forming the left and right horizontal frames 18 at a slightly higher position, and fixing vertical support frames 69 hanging downward at their upstream ends with a gap between them and the concrete base 4, and erecting capture rods 29 between the left and right vertical support frames 69 with a gap in the vertical direction.

[0084] As described above, the permeable dam 1 has a secondary dam 3 downstream of the main dam 2, and a weir section 52 on the secondary dam 3 that is approximately the same height as the upper end of the water passage opening 30 of the main dam 2, and a slit 56 is provided in this weir section 52.This allows a portion of the river flowing water to be dammed, allowing the main dam to effectively perform its sediment control function.

[0085] If the accumulated sediment 63 is periodically removed using heavy machinery, the permeable dam 1 will be able to perform its sediment adjustment and capture functions for many years.

[0086] During floods, the river flow increases beyond the opening of the main levee 22, from the inclined strait 27 to near or above the top. In such cases, the catcher 9 of the main levee performs its catch function and catches gravel, soil, and the like.

[0087] Example 2 A second embodiment of the transmission type dam according to the present invention will be described with reference to Fig. 8(a). A transmission type dam 91 of the second embodiment is substantially the same as the transmission type dam 1 of the first embodiment. The difference is in the configuration for protecting the inclined frame support pillars 19 and the horizontal frame support pillars 20 of the support frame 13.

[0088] The lower parts of the inclined frame support pillars 19 and the horizontal frame support pillars 20 are each protected by a steel protective cylinder 92 from the periphery up to the position of the horizontal buried reinforcement 35. By protecting the support frame 13 with such a steel protective cylinder 92, the structure can withstand rapids in rivers when the water level rises.

[0089] Example 3 Example 3 of a permeable dam according to the present invention will be described with reference to Fig. 8(b). A permeable dam 81 of Example 3 is substantially the same as the permeable dam 1 of Example 1. The difference is in the configuration of a steel shell 82 that encases the oval concrete body 34 from the outside to protect the support frame 13.

[0090] The steel shell 82 is integrally provided with an upstream section 83 and a downstream section 84. The upstream section 83 has the same shape as the upstream portion of the oval concrete body 34, and contains and protects the horizontal frame 18 and the horizontal frame support columns 20.

[0091] The downstream section 84 is configured as shown in Fig. 8(b) so as to enclose the oval concrete body 34 from the outside and also enclose the entire upper inclined frame 17 from all sides. This steel shell 82 protects the support frame 13 and is configured to withstand rapids in rivers when the water level rises.

[0092] Example 4 A fourth embodiment of the permeable dam according to the present invention will be described with reference to Figs. 9(a) and (b). The action and function of the permeable dam 101 of the fourth embodiment is the same as that of the permeable dam 1 of the first embodiment, and its configuration corresponds to a simplified configuration of the main dam of the permeable dam 81 of the third embodiment.

[0093] The permeable dam 101 of Example 4 employs a structure in which a steel shell encases a support frame supporting the lattice part 14, similar to the main dam of the permeable dam 81 of Example 3. However, in the main dam 102 of the permeable dam 101, the support frame supporting the lattice part 14 is a concrete structure 103 constructed on a concrete base 4, as shown in FIG.

[0094] The main dam 102 of the permeable dam 101 of the fourth embodiment has a concrete structure 103 as shown in FIG.

[0095] A plurality of such concrete structures 103 are arranged in a row in the width direction of the river between the left and right side walls, and a grate section 14 having an inclined grate section 27 and a horizontal grate section 28 is provided between adjacent concrete structures 103.

[0096] In the permeable dam 101 of Example 4, the lower part of the horizontal grate section 28 also serves as an opening 30 for water passage, and during sweeping, the river water flows mainly through this opening 30 downstream toward the secondary dam 3, and together with the secondary dam 3, it performs a sediment storage function.

[0097] The above describes the form for implementing the permeable dam according to the present invention based on the examples. However, the present invention is not limited to such examples, and it goes without saying that there are various embodiments within the scope of the technical matters described in the claims. [Industrial Applicability]

[0098] Since the permeable dam of the present invention has the above-mentioned configuration, it can be applied to a gently sloping section of a river where sediment movement is active. [Explanation of symbols]

[0099] 1. Permeable dam 2 main embankments 3 sub-propositions 4. Concrete Foundation 8. Side wall of embankment 9. Capture Body 12 Acquisition Unit 13 Support frame 14. The slatted section 17 Inclined Frame 18 Horizontal Frame 19 Inclined frame support column 20 Horizontal frame support column 24 Horizontal rod between left and right horizontal frames 25 Lifting support rod 27 Inclined Basket Section 28 Horizontal slats 29 Capture rod 30 Water passage opening of the main embankment 34 Oval concrete body 35 Horizontal buried reinforcement body 37 Capture Unit 38 Horizontal frame support column 39 Horizontal rod 40 Triangular Frame 41 Top of the triangular frame 44 Hanging support rod 51 Left and right side walls of secondary embankment 52 Weir 53 Overflow of secondary embankment 56 Slit 57 Top of the weir 63 Sediment 64 Sediment shoulder 65 Space 66 Slope of accumulated sediment 68 Vertical cage child part 69 Vertical support frame 70 Gap 81 Permeable Dam 82 Steel shell 83 Upstream of steel hull 84 Downstream of steel hull 91 Permeable Dam 92 Steel protective cylinder 101 Permeable dam 102 Main embankment 103 Concrete Structure 108 Steel shell

Claims

1. A permeable dam to be installed in a river sweep section, comprising a main dam constructed on a concrete foundation and a sub-dam constructed downstream of the main dam, The main structure includes left and right side walls and a catcher provided between the left and right side walls. The capture body includes a support frame and a lattice portion having a plurality of capture rods disposed at intervals between the support frame, The drainage section has an inclined drainage section and a horizontal drainage section, A horizontal buried reinforcement body is buried in the concrete foundation so as to extend horizontally from the main embankment to a position directly below the secondary embankment. The secondary embankment has left and right side walls on a concrete base and a dam section between the left and right side walls, and is generally concave-shaped when viewed from the upstream side. A slit is formed downward from the top of the dam section. A permeable dam characterized in that the water passage width, which is the width between the left and right side walls of the main dam, is the same as the overflow width, which is the width between the left and right side walls of the secondary dam, and the height from the concrete foundation to the horizontal frame of the main dam is approximately the same as the height of the weir part of the secondary dam.

2. A permeable dam is provided in a river sweep section, the permeable dam being provided with a main dam constructed on a concrete foundation and a sub-dam constructed downstream of the main dam, The main structure includes left and right side walls and a catcher provided between the left and right side walls. The trapping body is composed of multiple trapping units arranged in parallel in the river width direction. The capture unit includes left and right support frames, and an inclined sieve portion and a horizontal sieve portion in which a plurality of capture rods are disposed at intervals between the left and right support frames; The lower ends of the left and right support frames are fixed to horizontally embedded reinforcements embedded in the concrete foundation so as to extend horizontally from the main bank to the position of the sub-bank. The secondary embankment has left and right side walls on a concrete base and a dam section between the left and right side walls, and is generally concave-shaped when viewed from the upstream side. A slit is formed downward from the top of the dam section. A permeable dam characterized in that the water passage width, which is the width between the left and right side walls of the main dam, is the same as the overflow width, which is the width between the left and right side walls of the secondary dam, and the height from the concrete foundation to the horizontal frame of the main dam is approximately the same as the height of the weir part of the secondary dam.

3. A permeable dam is provided in a river sweep section, the permeable dam being provided with a main dam constructed on a concrete foundation and a sub-dam constructed downstream of the main dam, The main structure is equipped with left and right side walls on a concrete base and a catcher between the left and right side walls. The trapping body is composed of multiple trapping units arranged in parallel in the river width direction. The capture unit includes left and right support frames, and an inclined sieve portion and a horizontal sieve portion in which a plurality of capture rods are disposed at intervals between the left and right support frames; The support frame body includes an inclined frame, a horizontal frame extending horizontally from a lower portion of the inclined frame toward the upstream side, and an inclined frame support column and a horizontal frame support column that support the inclined frame and the horizontal frame on a concrete foundation, respectively; The inclined frame support pillars and the vertical frame support pillars of the adjacent capture units are supported by penetrating an oval concrete body in a plan view, and their lower ends are fixed to a horizontal buried reinforcement body that is buried in the concrete foundation so as to extend horizontally from the main bank to the position of the sub-bank, The secondary embankment has left and right side walls on a concrete base and a dam section between the left and right side walls, and is generally concave-shaped when viewed from the upstream side. A slit is formed downward from the top of the dam section. A permeable dam characterized in that the water passage width, which is the width between the left and right side walls of the main dam, is the same as the overflow width, which is the width between the left and right side walls of the secondary dam, and the height from the concrete foundation to the horizontal frame of the main dam is approximately the same as the height of the weir part of the secondary dam.

4. 4. The transparent dam according to claim 3, wherein the horizontal frame support pillars are vertical or inclined pillars.

5. A permeable dam as described in claim 3 or 4, characterized in that a cross rod is installed between the left and right horizontal frames, and a lifting rod is installed between each of the left and right horizontal frame support pillars and the cross rod.

6. A permeable dam as described in claim 2, 3 or 4, characterized in that a cross rod is installed between left and right horizontal frames, and the left and right horizontal frames are provided with triangular side frames with the horizontal frames as their bases, and a suspension rod is installed between the tops of the left and right triangular side frames and the cross rod.

7. A permeable dam as described in claim 2 or 3, characterized in that a vertical support frame is fixed to the left and right horizontal frames, facing downward from its tip, with a gap between the frame and the concrete base, capture rods are erected between the left and right vertical support frames with a gap in the vertical direction, and a vertical grating section is provided.

8. 4. The permeable dam described in 3, characterized in that the inclined frame support pillar and the horizontal frame support pillar are each protected by a steel protective cylinder fitted therein.

9. 4. The permeable dam described in 3, wherein the inclined frame support pillar and the horizontal frame support pillar are each configured to penetrate an oval-shaped concrete body on the concrete foundation.

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