Traps and dams

Abstract

To prevent a capturing body from being broken by rocks or drift wood flowing over the capturing body.SOLUTION: A capturing body (3), which allows flowing water from upstream of a river to pass through and captures objects included in the flowing water, is disposed on an upstream side of the river and comprises: an upstream side unit (6) to capture the objects; a downstream side unit (7) that is disposed on a downstream side of the river and has a central part formed by being bent so as to protrude toward the upstream side unit (6); and connection units (8) that connect the upstream side unit (6) and the downstream side unit (7). Ends of the downstream side unit (7) are fitted to non-overflow sections (1) built on both sides of the capturing body (3) in a direction crossing the river. Cover unit (9) covering at least a portion of an opening (S) formed between the upstream side unit (6) and the downstream side unit (7) are provided.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a trap and a dam. [Background technology]

[0002] A well-known example of a river debris flow countermeasure is a dam (so-called permeable dam) equipped with a trapping body that captures rocks, driftwood, and other debris flowing from upstream. The dam has a pair of non-overflow sections that protrude from both sides of the river, with an opening between the non-overflow sections to allow water to pass through. The trap is installed in the opening and traps large-diameter rocks, driftwood, etc. while allowing small-diameter sediment and water to pass through. The trap has an upstream unit facing upstream in the direction of river flow and a downstream unit facing downstream, with both units extending at an angle so that they approach each other as they extend upward and are connected to each other near their upper ends. The trap is installed across the width of the opening and its lower end is attached to a concrete foundation (see, for example, Patent Document 1). When a debris flow hits the trap, a force acts that tries to tip the trap downstream. The trap transmits this force from its lower end to the concrete foundation to prevent it from tipping over. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-101502 Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, in large rivers and rivers where large debris flows are predicted, high dams with a height of 15m or more from the bottom of the concrete foundation to the top are often constructed. In the case of high dams, the trapping body also needs to be constructed high, but since the upstream and downstream units extend at an angle so that they approach each other as they go upward, the higher the trapping body, the greater the distance between its top and bottom ends along the direction of the river flow. As a result, there was a problem in that rocks and driftwood that had climbed over the trapping body would fall toward the lower end of the downstream unit, damaging the downstream unit and making it unable to transmit the force acting on the trapping body to the concrete foundation.

[0005] Therefore, the present invention has been made in consideration of the above problems, and aims to provide a technology that prevents a trap from being damaged by rocks or driftwood that climb over the trap. [Means for solving the problem]

[0006] One aspect of the present invention is a capture body that allows flowing water from upstream of a river to pass through and captures objects contained in the flowing water, and comprises: an upstream unit that is provided on the upstream side of the river and captures the objects; a downstream unit that is provided on the downstream side of the river and is formed by bending its central portion so that it protrudes toward the upstream unit; and a connecting unit that connects the upstream unit and the downstream unit, wherein each end of the downstream unit is attached to a non-overflow portion constructed on both sides of the capture body in the direction across the river, and a cover unit that covers at least a portion of the opening formed between the upstream unit and the downstream unit.

[0007] Preferably, the cover unit is provided across from the upper end of the upstream unit to the upper end of the downstream unit.

[0008] Preferably, the cover unit has a first cover portion provided along a direction connecting the upstream unit and the downstream unit.

[0009] Preferably, the cover unit has a second cover portion provided along a direction intersecting the first cover portion.

[0010] It is also preferable that the first cover portion and the second cover portion are connected to each other.

[0011] It is also preferable that a plurality of the first cover portions are provided, and at least some of the first cover portions have one end connected to the upstream unit and the other end connected to the downstream unit.

[0012] The cover unit preferably has a plate member that covers the opening.

[0013] The cover unit preferably has a mesh material that covers the opening.

[0014] Furthermore, it is preferable that the upstream unit is formed by bending the central portion so that it protrudes toward the upstream side of the river, and that each end of the upstream unit is attached to a non-overflow portion constructed on both sides of the capture body in the direction crossing the river.

[0015] One aspect of the present invention is a dam characterized by comprising a pair of non-overflow sections protruding from both banks of a river, and the above-mentioned capture body provided in an opening between the pair of non-overflow sections. [Effects of the Invention]

[0016] According to one aspect of the present invention, the trapping body is not damaged by rocks or driftwood that climb over it. [Brief explanation of the drawings]

[0017] [Figure 1] This is an oblique view of a dam with the inside of the non-overflow section visible. [Figure 2] FIG. [Figure 3] FIG. 10 is a plan view of the capture body of the dam. [Figure 4] FIG. 4 is an enlarged plan view of a portion of the cover unit. [Figure 5] FIG. 4 is an enlarged side view of a portion of the cover unit. [Figure 6] FIG. 1 is a diagram illustrating a method for constructing a dam. [Figure 7] FIG. 1 is a diagram illustrating a method for constructing a dam. [Figure 8] FIG. 1 is a diagram illustrating a method for constructing a dam. [Figure 9] FIG. 1 is a diagram illustrating a method for constructing a dam. [Figure 10] FIG. 1 is a diagram illustrating a method for constructing a dam. [Figure 11] FIG. [Figure 12] 10 is a plan view showing another form of the cover unit of the capture body. FIG. [Figure 13] 10 is a plan view showing another form of the cover unit of the capture body. FIG. [Figure 14] FIG. 10 is a perspective view showing a modified example of a dam with the inside of the non-overflow section seen through. [Figure 15] FIG. 10 is a plan view of a capture body in a modified dam. DETAILED DESCRIPTION OF THE INVENTION

[0018] Preferred embodiments of the present invention will now be described with reference to the drawings. <Dam configuration> 1 to 3, dam 100 is generally called a permeable dam and comprises a pair of non-overflow sections 1, an opening 2, a capture body 3, and a mount 4. In the following, the vertical direction refers to the height direction of dam 100 (depth direction of the river), and the horizontal direction refers to the width direction of dam 100 (width direction of the river) which is perpendicular to the height direction of dam 100.

[0019] The non-overflow sections 1 are, for example, walls made of concrete. The pair of non-overflow sections 1 extend from both banks of the river toward the center of the river, crossing the river. A predetermined gap is provided between the pair of non-overflow sections 1, and an opening 2 is formed therein. The non-overflow sections 1 are constructed by pouring concrete upward onto a foundation 11 (see Figure 6) formed on the riverbed.

[0020] The opening 2 is a space formed between a pair of non-overflow sections 1, and a capture body 3 is installed therein. This allows large rocks and driftwood contained in the debris flow to be captured by the capture body 3, while allowing water, sand, small pebbles, etc. to pass through. A foundation 21 is formed at the bottom of the opening 2. The foundation 21 is formed on the riverbed and is made of, for example, concrete.

[0021] The trapping body 3 allows water flowing from upstream of the river to pass through while trapping objects such as large rocks and driftwood. At the opening 2, it is attached to the base 21 of the opening 2 and to the sides of the non-overflow section 1 on both sides of the river flow direction (both sides in the direction crossing the river). The trapping body 3 is used, for example, in a high dam. Here, a "high dam" refers to a dam whose height (dam height) from the riverbed (bottom) of the river on which the dam foundation is installed to the top of the trapping body 3 is 15 m or more. High dams are mainly installed in large rivers and rivers where large debris flows are predicted.

[0022] The capture body 3 includes an upstream unit 6, a downstream unit 7, a connecting unit 8, and a cover unit 9. The upstream unit 6 is installed on the upstream side of the river and is a functional component that captures objects such as rocks and driftwood contained in the debris flow that has flowed down from the upstream side of the dam 100. In other words, the upstream unit 6 is the unit that is directly subjected to the impact of the debris flow. When the dam 100 is viewed from above, the upstream unit 6 is provided linearly along the direction across the river (the width direction of the dam 100). The upstream unit 6 includes a plurality of vertical members 61 and a plurality of horizontal members 62 .

[0023] The multiple vertical members 61 are arranged along the height direction of the dam 100, and horizontal members 61 adjacent to each other in the height direction are connected. The multiple vertical members 61 are arranged side by side along the width direction of the dam 100. The spacing between adjacent vertical members 61 is preferably set smaller than the diameter of the rocks to be captured in the event of a debris flow. The spacing between adjacent vertical members 61 may be the same from one end of the capture body 3 to the other in the width direction, or may be narrowed only near the center of the capture body 3 in the width direction, and can be freely changed depending on the expected scale of the debris flow. The vertical members 61 are formed, for example, from cylindrical steel pipes with a straight axis along the longitudinal direction. In the capture body 3, multiple vertical members 61 are connected in the longitudinal direction, and each vertical member 61 is connected to each other via flanges provided at the longitudinal ends. For example, the capture body 3 includes three vertical members 61. Note that the vertical members 61 may be connected by welding their ends together without providing flanges, but considering the need for replacement after a debris flow collision, connection using flanges is preferable.

[0024] Each vertical member 61 has a plurality of connecting portions 63, 64 that connect to the horizontal members 62 between the ends in the longitudinal direction. Specifically, the vertical member 61, which is disposed at the lowest position in the capture body 3 and whose lower end is embedded in the foundation 21 of the opening 2, has two first connecting portions 63 connecting adjacent horizontal members 62 between its longitudinal ends and two second connecting portions 64 connecting adjacent horizontal members 62. The pair of first connecting portions 63 and second connecting portions 64 are provided at the same height. The first connecting portions 63 and second connecting portions 64 are formed, for example, from cylindrical steel pipes whose longitudinal axes are straight. The first connecting portions 63 and second connecting portions 64 extend in a direction perpendicular to the longitudinal direction of the vertical member 61, with one end joined to the vertical member 61 by welding or the like and the other end provided with a flange portion for connecting to the horizontal member 62. Note that one end of the first connecting portions 63 and second connecting portions 64 may be connected to the vertical member 61 via a flange portion.

[0025] The vertical member 61 arranged in the second lowest row of the capture body 3 has three first connecting portions 63 connecting adjacent horizontal members 62 between their longitudinal ends and three second connecting portions 64 connecting adjacent horizontal members 62 between their longitudinal ends. The paired first connecting portions 63 and second connecting portions 64 are located at the same height. The first connecting portions 63 and second connecting portions 64 are formed, for example, from cylindrical steel pipes whose longitudinal axes are straight. The first connecting portions 63 and second connecting portions 64 extend in a direction perpendicular to the longitudinal direction of the vertical member 61. One end of each connecting portion 63 and second connecting portion 64 is joined to the vertical member 61 by welding or the like, and the other end is provided with a flange portion that connects to the horizontal member 62. Note that one end of each of the first connecting portions 63 and second connecting portions 64 may be connected to the vertical member 61 via a flange portion.

[0026] The vertical member 61 located at the top of the capture body 3 has five first connecting portions 63 connecting adjacent horizontal members 62 between their longitudinal ends and five second connecting portions 64 connecting adjacent horizontal members 62 between their longitudinal ends. The paired first connecting portions 63 and second connecting portions 64 are located at the same height. The first connecting portions 63 and second connecting portions 64 are formed, for example, from cylindrical steel pipes whose longitudinal axes are straight. The first connecting portions 63 and second connecting portions 64 extend in a direction perpendicular to the longitudinal direction of the vertical member 61. One end of each connecting portion 63 and second connecting portion 64 is joined to the vertical member 61 by welding or the like, and the other end is provided with a flange portion that connects to the horizontal member 62. One end of each connecting portion 63 and second connecting portion 64 may be connected to the vertical member 61 via a flange portion.

[0027] The multiple horizontal members 62 are provided in a direction that crosses the river, and are arranged side by side along the height direction of the dam 100. The spacing between adjacent horizontal members 62 is preferably set smaller than the diameter of the rocks to be captured in the event of a debris flow. The spacing between adjacent horizontal members 62 may be the same from the top to the bottom of the capture body 3, or may be narrowed only above the capture body 3, and can be freely changed depending on the expected scale of the debris flow. The horizontal members 62 are formed, for example, from cylindrical steel pipes with a straight axis along the longitudinal direction. Each horizontal member 62 is connected to a first connecting portion 63 and a second connecting portion 64 of the vertical members 61 via flanges provided at the longitudinal ends. Note that the ends of each horizontal member 62 may be connected by welding without providing flanges, but considering the need for replacement after a debris flow collision, connection using flanges is preferable. Of the cross members 62, the cross members 62 positioned outermost in the width direction of the river have one longitudinal end attached to the side wall of the opposing non-overflow section 1. Specifically, as shown in Figure 1, the ends of the cross members 62 are connected to the frame 4, and the frame 4 is buried in the non-overflow section 1, thereby fixing each cross member 62 to the non-overflow section 1.

[0028] The downstream unit 7 is located downstream of the river when viewed from the upstream unit 6, and the impact load of the debris flow acting on the upstream unit 6 is transmitted via the connecting unit 8 to support the capture body 3. When the dam 100 is viewed from above, the downstream unit 7 is arranged in a direction that crosses the river, and is bent so that its central portion in the extension direction protrudes toward the upstream unit 6. In other words, the downstream unit 7 employs an arch structure, and is a structural member that uses compressive force to support the impact load of the debris flow transmitted from the upstream unit 6 via the connecting unit 8. The downstream unit 7 includes a plurality of vertical members 71 and a plurality of horizontal members 72 .

[0029] The multiple vertical members 71 are arranged along the height direction of the dam 100, and horizontal members 71 adjacent to each other in the height direction are connected. The multiple vertical members 71 are arranged side by side along the width direction of the dam 100. The spacing between adjacent vertical members 71 is preferably set smaller than the diameter of the rocks to be captured in the event of a debris flow. The spacing between adjacent vertical members 71 may be the same from one end of the capture body 3 to the other in the width direction, or may be narrowed only near the center of the capture body 3 in the width direction, and can be freely changed depending on the expected scale of the debris flow. The vertical members 71 are formed, for example, from cylindrical steel pipes whose longitudinal axes are straight. In the capture body 3, multiple vertical members 71 are connected in the longitudinal direction, and each vertical member 71 is connected to one another via flanges provided at the longitudinal ends. For example, the capture body 3 includes three vertical members 71. Note that the vertical members 71 may be connected by welding their ends together without providing flanges, but considering the need for replacement after a debris flow collision, connection using flanges is preferable.

[0030] Each vertical member 71 has a plurality of connecting portions 73, 74 that connect to the horizontal members 72 between the longitudinal ends. Specifically, the vertical member 71, which is disposed at the lowest position in the capture body 3 and whose lower end is embedded in the foundation 21 of the opening 2, has two first connecting portions 73 connecting adjacent horizontal members 72 between its longitudinal ends and two second connecting portions 74 connecting adjacent horizontal members 72. The pair of first connecting portions 73 and second connecting portions 74 are provided at the same height. The first connecting portions 73 and second connecting portions 74 are formed, for example, from cylindrical steel pipes whose longitudinal axes are straight. The first connecting portions 73 and second connecting portions 74 extend in a direction perpendicular to the longitudinal direction of the vertical member 71, with one end joined to the vertical member 71 by welding or the like and the other end provided with a flange portion for connecting to the horizontal member 72. Note that one end of the first connecting portions 73 and second connecting portions 74 may be connected to the vertical member 71 via a flange portion.

[0031] The vertical member 71 arranged in the second lowest row of the capture body 3 has three first connecting portions 73 connecting adjacent horizontal members 72 between their longitudinal ends and three second connecting portions 74 connecting adjacent horizontal members 72 between their longitudinal ends. The paired first connecting portions 73 and second connecting portions 74 are located at the same height. The first connecting portions 73 and second connecting portions 74 are formed, for example, from cylindrical steel pipes whose longitudinal axes are straight. The first connecting portions 73 and second connecting portions 74 extend in a direction perpendicular to the longitudinal direction of the vertical member 71. One end of each connecting portion 73 and second connecting portion 74 is joined to the vertical member 71 by welding or the like, and the other end has a flange portion that connects to the horizontal member 72. Note that one end of each of the first connecting portions 73 and second connecting portions 74 may be connected to the vertical member 71 via a flange portion.

[0032] The vertical member 71 located at the top of the capture body 3 has five first connecting portions 73 connecting adjacent horizontal members 72 between their longitudinal ends and five second connecting portions 74 connecting adjacent horizontal members 72 between their longitudinal ends. The paired first connecting portions 73 and second connecting portions 74 are located at the same height. The first connecting portions 73 and second connecting portions 74 are formed, for example, from cylindrical steel pipes whose longitudinal axes are straight. The first connecting portions 73 and second connecting portions 74 extend in a direction perpendicular to the longitudinal direction of the vertical member 71. One end of each connecting portion 73 and second connecting portion 74 is joined to the vertical member 71 by welding or the like, and the other end is provided with a flange portion that connects to the horizontal member 72. One end of each connecting portion 73 and second connecting portion 74 may be connected to the vertical member 71 via a flange portion.

[0033] The multiple cross members 72 are arranged in a direction that crosses the river, and are lined up along the height direction of the dam 100. The spacing between adjacent cross members 72 is preferably set smaller than the diameter of the rocks to be captured in the event of a debris flow. The spacing between adjacent cross members 72 may be the same from the top to the bottom of the capture body 3, or may be freely changed depending on the expected scale of the debris flow, such as by narrowing the spacing only above the capture body 3. The cross members 72 are arranged in a position facing the cross member 62 of the upstream unit 6 in the direction of the river flow. The horizontal members 72 are formed, for example, from cylindrical steel pipes with a straight longitudinal axis. Each horizontal member 72 is connected to the first connecting portion 73 and the second connecting portion 74 of the vertical members 71 via flanges provided at the longitudinal ends. Because each horizontal member 72 is required to be able to withstand the impact load of a debris flow, it is preferable to use a steel pipe with a larger diameter and higher strength than the steel pipes that make up the horizontal members 62 of the upstream unit 6. Note that the ends of each horizontal member 72 may be connected by welding without providing flanges, but connection using flanges is preferable in consideration of replacement work after a debris flow collision. Of the cross members 72, the cross members 72 positioned outermost in the width direction of the river have one longitudinal end attached to the side wall of the opposing non-overflow section 1. Specifically, as shown in Figure 1, the ends of the cross members 72 are connected to a frame 4, and by embedding this frame 4 in the non-overflow section 1, each cross member 72 is fixed to the non-overflow section 1.

[0034] Of the downstream unit 7, the cross member 72 arranged in the center in the extension direction (axial direction) of the cross member 72 is located closest to the cross member 62 of the upstream unit 6, and the cross members 72 are located farther away from the cross member 62 of the upstream unit 6 as they move towards the end of the cross member 72. By connecting the cross members 72 to each other in this arrangement, the downstream unit 7 can be formed into an arch shape.

[0035] The connecting unit 8 connects the upstream unit 6 and the downstream unit 7 together. The connection units 8 are arranged along the river flow direction and connect the opposing vertical members 61 of the upstream unit 6 and the vertical members 71 of the downstream unit 7. That is, like the horizontal members 62, 72, the connection units 8 are arranged side by side along the height direction of the dam 100. Therefore, the spacing between adjacent connection units 8 is set to be smaller than the diameter of the rocks to be captured in the event of a debris flow. Furthermore, like the horizontal members 62, 72, the spacing between adjacent connection units 8 may be the same from the top to the bottom of the capture body 3, or may be narrowed only above the capture body 3, and can be freely changed depending on the expected scale of the debris flow. The connecting units 8 are formed, for example, from cylindrical steel pipes with a straight longitudinal axis. The connecting units 8 arranged near the widthwise center of the trapping body 3 are relatively short, so one end is connected to the vertical member 61 of the upstream unit 6 via a flange, and the other end is connected by welding to the vertical member 71 of the downstream unit 7. On the other hand, the connecting units 8 arranged near the widthwise ends of the trapping body 3 are relatively long, so one end is connected to the vertical member 61 of the upstream unit 6 via a flange, and the other end is connected to the vertical member 71 of the downstream unit 7 via a flange. The connection unit 8 is not necessarily limited to connection using a flange portion, and may be joined by welding or the like.

[0036] As shown in Figures 3 to 5, the cover unit 9 covers at least a portion of the opening S formed between the upstream unit 6 and the downstream unit 7, preventing rocks and driftwood from falling into the opening S and damaging the upstream unit 6 and the downstream unit 7. The cover unit 9 is provided across from the upper end of the upstream unit 6 to the upper end of the downstream unit 7 . The cover unit 9 includes a connecting portion 91 , a first arm portion 92 , and a second arm portion 93 .

[0037] The connecting portion 91 is made of a straight steel pipe, and one end is connected to the cross member 62 located at the top of the upstream unit 6, and the other end is connected to the cross member 72 located at the top of the downstream unit 7. The connecting portion 91 is provided between adjacent connecting units 8, and is arranged parallel to the connecting units 8. Here, in FIG. 3, only one connecting portion 91 is provided between adjacent connecting units 8, but multiple connecting portions 91 may be provided depending on the spacing between adjacent connecting units 8. The connecting portion 91, which is located near the widthwise center of the capture body 3, is relatively short, so one end is connected to the cross member 62 of the upstream unit 6 via a flange, and the other end is connected by welding to the cross member 72 of the downstream unit 7. On the other hand, the connecting portion 91, which is located near the widthwise end of the capture body 3, is relatively long, so one end is connected to the cross member 62 of the upstream unit 6 via a flange, and the other end is connected to the cross member 72 of the downstream unit 7 via a flange. The connecting portion 91 is not necessarily limited to a connection using a flange portion, but may be connected by welding or the like.

[0038] The first arm 92 is provided on the connecting unit 8 and the connecting portion 91 that connect the upstream unit 6 and the downstream unit 7. The first arm 92 is made of a straight steel pipe, one end of which is connected to the connecting unit 8 or the connecting portion 91 by welding or the like, and the other end is a free end. In other words, the first arm 92 is provided on the connecting unit 8 or the connecting portion 91 in a cantilevered state. The first arm 92 is made of a steel pipe having a diameter smaller than that of the connecting unit 8 or the connecting portion 91. The first arm 92 is provided on the connecting unit 8 or the connecting portion 91 so that its longitudinal direction is perpendicular to the longitudinal direction of the connecting unit 8 or the connecting portion 91. A plurality of first arms 92 are provided on one connection unit 8 or connection portion 91. Of the plurality of first arms 92 provided on one connection unit 8 or connection portion 91, at least one pair of first arms 92 are provided at positions opposing each other across the connection unit 8 or connection portion 91, with their respective tips extending in opposite directions. The many first arm portions 92 provided on adjacent connection units 8 or connection portions 91 are provided so that the free ends thereof face each other with a small gap therebetween. A hole penetrating in the radial direction is formed in the first arm portion 92. This hole is a hole for a fastener used when connecting to the second arm portion 93.

[0039] The second arm 93 is placed on and connected to the first arm 92. The second arm 93 is made of a straight steel pipe and is connected to the first arm 92 with its longitudinal direction perpendicular to the longitudinal direction of the first arm 92, in other words, parallel to the longitudinal direction of the connecting unit 8 or the connecting portion 91. One end of the second arm 93 faces the side surface of the cross member 62 of the upstream unit 6 with a small gap therebetween, and the other end faces the side surface of the cross member 72 of the downstream unit 7 with a small gap therebetween. One end of the second arm 93 is cut off at an angle to avoid contact with the cross member 62 of the upstream unit 6.

[0040] At least a pair of mounting plates 94 are provided on the outer peripheral surface of the second arm portion 93 on the side facing the first arm portion 92. The pair of mounting plates 94 are provided on the second arm portion 93 with a distance from each other that is slightly larger than the outer diameter of the first arm portion 92. The pair of mounting plates 94 are provided on the second arm portion 93 so that their surfaces are along the cross-sectional direction (radial direction) of the second arm portion 93. This allows the first arm portion 93 to be sandwiched between the mounting plates 94 in the radial direction when the second arm portion 93 is placed on the first arm portion 92. Note that the second arm portion 93 is supported and connected to the first arm portion 92 at at least two locations, and therefore at least two pairs of mounting plates 94 are provided on the second arm portion 93. Each mounting plate 94 has a hole formed at a position opposite to the hole formed in the first arm portion 92. This hole is a hole for a fastener used to connect the first arm portion 92 and the second arm portion 93. The fastener connecting the first arm portion 92 and the second arm portion 93 consists of a bolt 95 and a nut 96. With the first arm portion 92 sandwiched between a pair of mounting plates 94, the bolt 95 is passed through one mounting plate 94, the first arm portion 92, and the other mounting plate 94 in that order, and the nut 96 is screwed onto the bolt 95 protruding from the other mounting plate 94, thereby connecting the first arm portion 92 and the second arm portion 93.

[0041] 3, the connecting unit 8 disposed in the widthwise center of the trap 3 is short due to the small distance between the upstream unit 6 and the downstream unit 7, and is provided with only a pair of first arms 92. In this case, the first arm 92 provided on the connecting portion 91 adjacent to the central connecting unit 8 extends to the vicinity of the connecting unit 8, and a second arm 93 is placed on and connected to this first arm 92 and the first arm 92 provided on the connecting unit 8. The other connecting units 8 and connecting parts 91 have multiple first arms 92 on both sides of the width of the capture body 3, and second arms 93 are placed on and connected to these first arms 92. The connecting units 8 and connecting parts 91 arranged near the width ends of the capture body 3 are long because the distance between the upstream unit 6 and the downstream unit 7 is large, and the number of first arms 92 is also large, and the second arms 93 are also long.

[0042] Here, the connecting portion 91 and the second arm portion 93 are provided along the direction connecting the upstream unit 6 and the downstream unit 7 (the direction of the river flow), and therefore function as a first cover portion. The first arm portion 92 is provided along a direction intersecting the connecting portion 91 and the second arm portion 93, and functions as a second cover portion.

[0043] The frame 4 is erected on the foundation 11 of the non-overflow section 1. The frame 4 is connected to the capture body 3, and when the dam 100 is completed, it will be buried in the non-overflow section 1 while still connected to the capture body 3. The mount 4 is used to firmly fix the capture body 3 to the non-overflow section 1. For each non-overflow section 1, the frame 4 is provided at a position facing the end of the cross member 62 of the upstream unit 6 and at a position facing the end of the cross member 72 of the downstream unit 7. Multiple frames 4 are connected along the height direction of the non-overflow section 1, and are provided at positions where each cross member 62, 72 of the capture body 3 can be connected. The mount 4 includes a plurality of vertical portions 41 and a plurality of horizontal portions 42.

[0044] A plurality of vertical portions 41 are provided along the height direction of the dam 100. The vertical portions 41 are formed, for example, from cylindrical steel pipes with a straight axis along the longitudinal direction. Flanges are provided at both ends of the vertical portions 41. The axial ends of each vertical portion 41 are connected to each other via the flanges. The lowest vertical portion 41 is provided directly on the foundation 11 (see Figure 7) of the non-overflow portion 1 and is buried in the foundation 11. As a result, the lower end of the frame 4 is erected on the foundation 11.

[0045] The horizontal portions 42 are arranged midway along the axial direction of the vertical portions 41 so as to intersect (orthogonally) with the vertical portions 41, and are arranged side by side along the height direction of the dam 100. The horizontal portions 42 are formed, for example, from cylindrical steel pipes whose longitudinal axes are straight. Each horizontal portion 42 is connected to the horizontal members 62, 72 of the capture body 3 via a flange provided at one end of the horizontal portion 42 in the axial direction. Each horizontal portion 42 is provided so as to penetrate some of the vertical portions 41 and is joined to the vertical portions 41 at their intersections. In other words, the frame 4 is configured as an integrated cross pipe having a generally cross shape when viewed from the front, in which the steel pipes constituting the vertical portions 41 and the steel pipes constituting the horizontal portions 42 are joined together. Each horizontal portion 42 is provided so that one longitudinal end portion is exposed to the opening 2 from the non-overflow portion 1, and is arranged so that this one end portion can be connected to the horizontal members 62, 72. The base 4 is buried in the non-overflow section 1 except for the connection portions between the horizontal members 62, 72 of the capture body 3 at the horizontal portion 42. By burying the base 4 in the non-overflow section 1, the ends of the horizontal members 62, 72 are fixed to the non-overflow section 1 via the base 4, and the capture body 3 is fixed to the side wall of the non-overflow section 1. The frame 4 extends in the height direction of the non-overflow section 1 by connecting the ends of the vertical sections 41 together.

[0046] <How to build a dam> Next, a method for constructing the dam 100 will be described. When constructing the dam 100, as shown in Figure 6, vertical members 61 are erected on the foundation 21 from near the center of the width of the opening 2 toward the non-overflow sections 1 on both banks, and adjacent vertical members 61 are connected with horizontal members 62 to assemble the dam. The horizontal members 62 are connected to the vertical members 61 by connecting them to first connecting portions 63 and second connecting portions 64 provided on the vertical members 61. Similarly to the upstream unit 6, the downstream unit 7 is assembled by erecting vertical members 71 on the foundation 21 from near the center of the width of the opening 2 toward the non-overflow sections 1 on both banks, and connecting adjacent vertical members 71 with horizontal members 72, as shown in Fig. 6. The horizontal members 72 are connected to the vertical members 71 by connecting them to first connecting portions 73 and second connecting portions 74 provided on the vertical members 71. Furthermore, the vertical members 61 of the upstream unit 6 and the vertical members 71 of the downstream unit 7 are connected by connecting units 8 (first step).

[0047] The process of erecting vertical members 61, 71 on foundation 21, connecting horizontal members 62, 72, and connecting vertical member 61 of upstream unit 6 and vertical member 71 of downstream unit 7 using connecting unit 8 is repeated until the ends of horizontal members 62, 72 each come very close to the construction area of ​​non-overflow section 1, as shown in Figure 7, and then erecting frame 4 on foundation 11 of non-overflow section 1 (second step).

[0048] After erecting the frame 4 on the foundation 11 of the non-overflow section 1, as shown in Fig. 8, the connecting portions 63, 64, 73, 74 of the vertical members 61, 71 extended up to a position adjacent to the non-overflow section 1 are connected to the ends of the horizontal portion 42 of the frame 4 by the horizontal members 62, 72. Here, one end of the horizontal members 62, 72 is connected to the connecting portions 63, 64, 73, 74 via a flange portion, and the other end of the horizontal members 62, 72 is connected to the horizontal portion 42 of the frame 4 via a flange portion (third step). This completes the lowest part of the capture body 3, and the horizontal member 62 at this lowest part is connected to the base 4.

[0049] Next, as shown in FIG. 9, concrete is poured into the foundation 11 of the non-overflow portion 1 to construct the non-overflow portion 1 (fourth step). Here, concrete is poured into the foundation 11 of the non-overflow section 1 so that the flange portion at the upper end of the vertical section 41 located at the top of the constructed frame 4 and the flange portion of the horizontal section 42 of the constructed frame 4 are exposed, and most of the frame 4 is buried in the non-overflow section 1. The fourth step may be performed after repeating the first to third steps a number of times. That is, the vertical members 61, 71, the horizontal members 62, 72, and the frame 4 may be connected in multiple stages, and then concrete may be poured into the foundation 11 of the non-overflow section 1 to construct the non-overflow section 1.

[0050] Simultaneously with the construction of the non-overflow section 1 in the fourth step, or before or after the construction of the non-overflow section 1, concrete is poured into the foundation 21 of the opening 2 and the lower ends of the vertical members 61, 71 are embedded in the concrete.

[0051] Next, as shown in Fig. 10, the first to third steps are repeated to connect the second vertical members 61, 71 to the vertical members 61, 71 that have already been erected on the foundation 21. That is, the new vertical members 61, 71 are connected to the upper ends of the lowest vertical members 61, 71, while the adjacent vertical members 61, 71 are connected with the horizontal members 62, 72. Furthermore, the vertical members 61 and 71 are connected with the connecting unit 8. Then, when the ends of the horizontal members 62, 72 have come very close to the construction area of ​​the non-overflow section 1, the vertical portion 41 of the new mounting frame 4 is connected to the upper end of the vertical portion 41 of the mounting frame 4. After that, the connecting portions 63, 64, 73, 74 of the vertical members 61, 71, which have been extended up to a position adjacent to the non-overflow section 1, are connected to the horizontal portion 42 of the mounting frame 4 by the horizontal members 62, 72. Thereafter, concrete is poured onto the upper end surface of the non-overflow section 1 to construct the non-overflow section 1. Here, concrete is poured onto the upper end surface of the non-overflow section 1 so that the flange portion at the upper end of the vertical section 41 located at the top of the constructed frame 4 and the flange portion of the horizontal section 42 of the constructed frame 4 are exposed, and most of the frame 4 is buried in the non-overflow section 1.

[0052] Next, the first to third steps are repeated to connect the third vertical member 61, 71 to the second vertical member 61, 71. That is, while connecting the new vertical member 61, 71 to the upper end of the second-stage vertical member 61, 71, adjacent vertical members 61, 71 are connected with the horizontal members 62, 72. Furthermore, the vertical member 61 and the vertical member 71 are connected with the connecting unit 8. At the top end, a cover unit 9 is provided to cover the opening S between the opposing horizontal members 62 and 72. Specifically, the opposing horizontal members 62 and 72 are connected by a connecting portion 91, and a second arm 93 is placed on a first arm 92 that is provided in advance on the connecting unit 8 and the connecting portion 91, thereby connecting the first arm 92 and the second arm 93. Note that the second arm 93 may also be connected to the first arm 92 in advance, and the connecting unit 8 and the connecting portion 91 provided with the first arm 92 and the second arm 93 may then be connected to the upstream unit 6 and the downstream unit 7 on site.

[0053] Then, when the ends of the horizontal members 62, 72 have come very close to the construction area of ​​the non-overflow section 1, the vertical portion 41 of the new mounting frame 4 is connected to the upper end of the vertical portion 41 of the mounting frame 4. After that, the connecting portions 63, 64, 73, 74 of the vertical members 61, 71, which have been extended up to a position adjacent to the non-overflow section 1, are connected to the horizontal portion 42 of the mounting frame 4 by the horizontal members 62, 72. Thereafter, concrete is poured onto the upper surface of the non-overflow section 1 to construct the non-overflow section 1. Here, concrete is poured onto the upper surface of the non-overflow section 1 so that the upper end of the vertical section 41 located at the top of the constructed frame 4 is completely hidden and the flange section of the horizontal section 42 of the constructed frame 4 is exposed, and most of the frame 4 is buried in the non-overflow section 1. Through the above steps, a dam 100 as shown in FIG. 11 is constructed.

[0054] According to the dam 100 described above, the horizontal members 72 constituting the downstream unit 7 are attached to the non-overflow section 1, so even if rocks or driftwood contained in a debris flow fly over the upper ends of the upstream unit 6 and the downstream unit 7 and fall below the capture body 3, the fallen rocks or driftwood are less likely to collide with the capture body 3, thereby suppressing damage to the capture body 3. Furthermore, the vertical members 71 are also erected in the same direction as the horizontal members 72 (the height direction of the capture body 3), so the vertical members 71 do not protrude downstream from the horizontal members 72 and will not be hit by fallen rocks or the like. Furthermore, since the cover unit 9 is provided to cover the opening S between the upstream unit 6 and the downstream unit 7, rocks and driftwood that have climbed over the trapping body 3 will not fall downward through the opening S, but can be guided to the downstream side of the trapping body 3. Furthermore, since water is less likely to enter the opening S, rocks and driftwood can be easily guided toward the downstream side of the trapping body 3. This prevents damage to the upstream unit 6 and the downstream unit 7 caused by rocks and driftwood that have entered the opening S. In particular, the closer one gets to the widthwise end of the trapping body 3 (the closer one gets to the non-overflow section 1), the greater the distance between the upstream unit 6 and the downstream unit 7 and the larger the area of ​​the opening S, so the cover unit 9 can more effectively prevent rocks and driftwood from entering the opening S. In addition, the second arm 93, which forms part of the upper end surface of the capture body 3, is connected to the first arm 92 with a bolt 95 and a nut 96, so that only the damaged part can be easily replaced.

[0055] Furthermore, since the capture body 3 is connected to a frame 4 embedded in the concrete that constitutes the non-overflow section 1, the capture body 3 is firmly fixed to the non-overflow section 1. This allows part of the debris flow load acting on the capture body 3 to be released to the non-overflow section 1, improving the resistance of the capture body 3 to being pushed out or pulled out. Furthermore, since the stand 4 has a simple structure consisting of vertical sections 41 and horizontal sections 42, both of which are made from steel pipes, the same materials can be used as the vertical members 61, 71 and horizontal members 62, 72 of the capture body 3, making the connection work easy.

[0056] <Other> Although the preferred embodiments of the present invention have been described, the present invention is not limited to the above embodiments and includes all aspects encompassed within the concept and scope of the claims. Furthermore, each configuration may be appropriately and selectively combined to achieve at least some of the above-described problems and effects. For example, the shape, material, arrangement, size, etc. of each component in the above embodiments may be appropriately modified depending on the specific usage of the present invention. For example, the size, shape, quantity, and arrangement of the connecting portion 91, first arm 92, and second arm 93 in the cover unit 9 can be freely changed. Adjacent connecting units 8 may be connected by the connecting portion 91, with the first arm 92 provided in a direction perpendicular to the connecting portion 91 and the second arm 93 provided in a direction perpendicular to the first arm 92. In other words, the first arm 92 may be provided along the direction connecting the upstream unit 6 and the downstream unit 7 (a direction perpendicular to the width direction of the capture body 3), and the connecting portion 91 and the second arm 93 may be provided along the width direction of the capture body 3. Furthermore, the connecting structure between the first arm portion 92 and the second arm portion 93 is not limited to the above embodiment. Furthermore, although an example in which the capture body 3 is provided on a dam 100 called a high dam has been described, it may also be provided on a dam that is not a high dam.

[0057] 12, the cover unit 9A may be configured with multiple plate members 93a instead of the second arm 93 formed from a steel pipe. Specifically, the cover unit 9A may be configured by preparing a plate member 93a corresponding to the size of the opening S between the upstream unit 6 and the downstream unit 7, attaching a mounting plate 94 to the underside of the plate member 93a by welding or the like, and connecting the mounting plate 94 to the first arm 92 with bolts 95 and nuts 96. The area covering the opening S with a single plate member 93a depends on the size of the plate member 93a. The plate member 93a may be configured to span multiple connecting units 8 and connecting portions 91, or a plate member 93a may be provided for each connecting unit 8 and connecting portion 91. In FIG. 12, the plate member 93a has holes 93b formed therein to avoid collision with the flanges of the connecting units 8 and connecting portions 91. The cover unit 9A may not be provided with the first arm 92, and the mounting plate 94 of the plate material 93a may be connected to a mounting plate provided on at least one of the connecting unit 8 and the connecting portion 91 with a bolt 95 and a nut 96. Also, the connecting portion 91 may be omitted, and the plate material 93a may be connected to the connecting unit 8. Furthermore, if the plate material 93a is sufficiently heavy, it may be possible to simply bridge the upstream unit 6 and the downstream unit 7 by using the weight of the plate material 93a without connecting it to the connecting unit 8. In other words, the connecting structure between the connecting unit 8, the connecting portion 91, and the plate material 93a can be freely changed. By covering the opening S with the plate material 93a, it becomes possible to prevent not only rocks and driftwood but also small-grained soil and sand from falling.

[0058] 13, the cover unit 9B may cover the opening S between the upstream unit 6 and the downstream unit 7 with a mesh member 93c instead of the first arm 92 and the second arm 93. Specifically, the cover unit 9B may be constructed by preparing a mesh member 93c that matches the size of the opening S between the upstream unit 6 and the downstream unit 7, attaching an attachment plate 94 to the underside of the mesh member 93c by welding or the like, and connecting the attachment plate 94 to the first arm 92 with bolts 95 and nuts 96. The area that a single mesh member 93c covers the opening S depends on the size of the mesh member 93c. The mesh member 93c may span multiple connecting units 8 and connecting portions 91, or a mesh member 93c may be provided for each connecting unit 8 and connecting portion 91. In FIG. 13, the mesh member 93c has holes 93d formed therein to avoid collision with the flanges of the connecting units 8 and connecting portions 91. The mesh material 93c is not limited to wire mesh, and expanded metal or grating may also be used. Furthermore, wire ropes may be attached to the corners of the mesh material 93c, and the wire ropes may be fixed to the non-overflow section 1 so that the mesh material 93c is installed in the opening S. By covering the opening S with the net material 93c, it becomes possible to prevent not only rocks and driftwood but also small-grained soil and sand from falling.

[0059] 14 and 15, a dam 200 may be provided with a cover unit 9C. The dam 200 differs from the dam 100 in the above embodiment in the configuration of the capture body, and the configuration of the capture body will be described below. As shown in FIGS. 14 and 15, the capture body 3A includes an upstream unit 6A, a downstream unit 7A, a connecting unit 8A, and a cover unit 9C. The upstream unit 6A is installed on the upstream side of the river and captures objects such as rocks and driftwood contained in the debris flow that has flowed down from the upstream side of the dam 200. In other words, the upstream unit 6A is the unit that is directly affected by the impact of the debris flow. When the dam 200 is viewed from above, the upstream unit 6A is provided in a direction that crosses the river, and is curved so that its central portion in the extension direction protrudes toward the upstream of the river. In other words, the upstream unit 6A employs a curved arch structure, which is designed to reduce the composite stress level due to the temperature stress of the upstream unit 6A (internal stress that occurs in a structure due to temperature changes (for example, stress due to expansion and contraction of each component due to changes in outside temperature)). The upstream unit 6A is configured by connecting a plurality of vertical members 61 and a plurality of horizontal members 62.

[0060] The multiple vertical members 61 are arranged along the height direction of the dam 200, and horizontal members 62 adjacent to each other in the height direction are connected. The multiple vertical members 61 are arranged side by side along the width direction of the dam 200. The spacing between adjacent vertical members 61 is preferably set smaller than the diameter of the rocks to be captured in the event of a debris flow. The spacing between adjacent vertical members 61 may be the same from one end of the capture body 3A to the other in the width direction, or may be narrowed only near the center of the capture body 3A in the width direction, and can be freely changed depending on the expected scale of the debris flow. The vertical members 61 are formed, for example, from cylindrical steel pipes with a straight axis along the longitudinal direction. In the capture body 3A, multiple vertical members 61 are connected in the longitudinal direction, and each vertical member 61 is connected to each other via flanges provided at the longitudinal ends. For example, as shown in FIG. 14, the capture body 3A includes three vertical members 61. Note that the vertical members 61 may be connected by welding their ends together without providing flanges, but considering the need for replacement after a debris flow collision, connection using flanges is preferable.

[0061] Each vertical member 61 has a plurality of connecting portions 63, 64 that connect to the horizontal members 62 between the ends in the longitudinal direction. Specifically, the vertical member 61, which is disposed at the lowest position in the capture body 3A and whose lower end is embedded in the foundation 21 of the opening 2, has two first connecting portions 63 connecting adjacent horizontal members 62 between its longitudinal ends and two second connecting portions 64 connecting adjacent horizontal members 62. The pair of first connecting portions 63 and second connecting portions 64 are provided at the same height. The first connecting portions 63 and second connecting portions 64 are formed, for example, from cylindrical steel pipes whose longitudinal axes are straight. The first connecting portions 63 and second connecting portions 64 extend in a direction perpendicular to the longitudinal direction of the vertical member 61, with one end joined to the vertical member 61 by welding or the like and the other end provided with a flange portion for connecting to the horizontal member 62. Note that one end of the first connecting portions 63 and second connecting portions 64 may be connected to the vertical member 61 via a flange portion.

[0062] The vertical member 61 arranged in the second lowest row of the capture body 3A has three first connecting portions 63 connecting adjacent horizontal members 62 between their longitudinal ends and three second connecting portions 64 connecting adjacent horizontal members 62 between their longitudinal ends. The paired first connecting portions 63 and second connecting portions 64 are located at the same height. The first connecting portions 63 and second connecting portions 64 are formed, for example, from cylindrical steel pipes with a straight longitudinal axis. The first connecting portions 63 and second connecting portions 64 extend in a direction perpendicular to the longitudinal direction of the vertical member 61. One end of each connecting portion 63 and second connecting portion 64 is joined to the vertical member 61 by welding or the like, and the other end has a flange portion that connects to the horizontal member 62. One end of each connecting portion 63 and second connecting portion 64 may be connected to the vertical member 61 via a flange portion.

[0063] The vertical member 61 located at the top of the capture body 3A has five first connecting portions 63 connecting adjacent horizontal members 62 between their longitudinal ends and five second connecting portions 64 connecting adjacent horizontal members 62 between their longitudinal ends. The paired first connecting portions 63 and second connecting portions 64 are located at the same height. The first connecting portions 63 and second connecting portions 64 are formed, for example, from cylindrical steel pipes whose longitudinal axes are straight. The first connecting portions 63 and second connecting portions 64 extend in a direction perpendicular to the longitudinal direction of the vertical member 61. One end of each connecting portion 63 and second connecting portion 64 is joined to the vertical member 61 by welding or the like, and the other end is provided with a flange portion that connects to the horizontal member 62. Note that one end of each of the first connecting portions 63 and second connecting portions 64 may be connected to the vertical member 61 via a flange portion.

[0064] The multiple cross members 62 are arranged in a direction across the river and are aligned along the height of the dam 200. The spacing between adjacent cross members 62 is preferably set smaller than the diameter of the rocks to be captured in the event of a debris flow. The spacing between adjacent cross members 62 may be the same from the top to the bottom of the capture body 3A, or, as shown in Figure 14, the spacing may be narrowed only above the capture body 3A, and can be freely changed depending on the expected scale of the debris flow. The cross members 62 are arranged in a position facing the cross member 72 of the downstream unit 7A in the direction of the river flow. The horizontal members 62 are formed, for example, from cylindrical steel pipes with a straight longitudinal axis. Each horizontal member 62 is connected to the first connecting portion 63 and the second connecting portion 64 of the vertical members 61 via flanges provided at the longitudinal ends. While the horizontal members 62 may be connected by welding their ends together without flanges, connection using flanges is preferable considering replacement work after a debris flow collision. The first connecting portion 63 and the second connecting portion 64 are attached to the vertical members 61 at a predetermined angle between their axes so that the horizontal members 62 form an arch shape. The degree of curvature of the beam portion connected to the horizontal members 62 is determined by the number of horizontal members 62 and the width of the capture body 3A. Of the cross members 62, the cross members 62 positioned outermost in the width direction of the river have one longitudinal end attached to the side wall of the opposing non-overflow section 1. Specifically, as shown in Figures 14 and 15, the ends of the cross members 62 are connected to the frame 4, and the frame 4 is buried in the non-overflow section 1, thereby fixing each cross member 62 to the non-overflow section 1. The configuration of the frame 4 is the same as that shown in Figure 1 above, so a description thereof will be omitted.

[0065] The downstream unit 7A is located downstream of the river as viewed from the upstream unit 6A, and the impact load of the debris flow acting on the upstream unit 6A is transmitted via the connecting unit 8A to support the capture body 3A. When the dam 200 is viewed from above, the downstream unit 7A is disposed in a direction that crosses the river, and is curved so that its central portion in the extension direction protrudes toward the upstream unit 6A. In other words, the downstream unit 7A employs a curved arch structure, and is a structural member that uses compressive force to support the impact load of the debris flow transmitted from the upstream unit 6A via the connecting unit 8A. The downstream unit 7A is configured by connecting a plurality of vertical members 71 and a plurality of horizontal members 72. The downstream unit 7A has the same configuration as the downstream unit 7 in the above embodiment, and therefore a description thereof will be omitted.

[0066] The connecting unit 8A connects the upstream unit 6A and the downstream unit 7A. The connection unit 8A is installed along the river flow direction and connects the opposing vertical members 61 of the upstream unit 6A and the vertical members 71 of the downstream unit 7A. That is, like the horizontal members 62 and 72, the connection units 8A are arranged side by side along the height direction of the dam 200. Therefore, the spacing between adjacent connection units 8A is set to be smaller than the diameter of the rocks to be captured in the event of a debris flow. Similarly to the horizontal members 62 and 72, the spacing between adjacent connection units 8A may be the same from the top to the bottom of the capture body 3A, or may be narrower only above the capture body 3A. This can be freely changed depending on the expected scale of the debris flow. The connection unit 8A is formed, for example, from a cylindrical steel pipe with a straight longitudinal axis. One end of the connecting unit 8A is connected to the vertical member 61 of the upstream unit 6A via a flange portion, and the other end is connected to the vertical member 71 of the downstream unit 7A via a flange portion. The connection unit 8A is not limited to connection via flange portions, and may be joined by welding or the like.

[0067] As shown in Figures 14 and 15, the cover unit 9C covers at least a portion of the opening S formed between the upstream unit 6A and the downstream unit 7A, preventing rocks and driftwood from falling into the opening S and damaging the upstream unit 6A and the downstream unit 7A. The cover unit 9C is provided across from the upper end of the upstream unit 6A to the upper end of the downstream unit 7A. The cover unit 9C includes a connecting portion 91, a first arm portion 92, and a second arm portion 93. The configuration of the cover unit 9C is similar to that of the cover unit 9 in the above embodiment, and therefore a description thereof will be omitted. The capture body 3A of the dam 200 is not limited to the cover unit 9C, and may be configured to include the cover unit 9A or the cover unit 9B described above.

[0068] As described above, dam 200 not only achieves the same effects as dam 100 in the above embodiment, but also, because upstream unit 6A is formed to be bent, it is possible to reduce the combined stress intensity due to temperature stress even when both ends are fixed to non-overflow section 1 via frame 4. This makes it possible to increase the strength of dam 200 while reducing the combined stress intensity due to temperature stress, and also makes it possible to reduce the steel pipe diameter of upstream unit 6A. Furthermore, by arranging the upstream unit 6A and the downstream unit 7A at equal intervals across the entire width of the capture body 3A, it is possible to standardize the vertical members 61, 71 and horizontal members 62, 72 of the upstream unit 6A and the downstream unit 7A, as well as the connecting unit 8A. This also makes it easy to install a cover unit 9C that connects the upper end of the upstream unit 6A with the upper end of the downstream unit 7A and prevents rocks and driftwood from falling between the upstream unit 6A and the downstream unit 7A. [Explanation of symbols]

[0069] 1 Non-overflow area 11 Basics 2 Opening 21 Basics 3, 3A capture object 4 Mounting stand 41 Vertical section 42 Horizontal 6, 6A Upstream unit 61 Vertical members 62 Cross member 63 First connection 64 Second connection 7, 7A downstream unit 71 Vertical members 72 Cross member 73 First connection 74 Second connection 8, 8A connecting unit 9, 9A, 9B, 9C cover unit 91 Connecting part 92 First Arm 93 Second Arm 93a Board material 93b hole 93c mesh material 93d hole 94 Mounting plate 95 volts 96 Nut 100, 200 dams S opening

Claims

1. A capture body that allows flowing water flowing from the upstream of a river to pass through and captures objects contained in the flowing water, an upstream unit provided on the upstream side of the river to capture the object; a downstream unit provided on the downstream side of the river, the downstream unit having a central portion bent so as to protrude toward the upstream unit; a connection unit that connects the upstream unit and the downstream unit, Each end of the downstream unit is attached to a non-overflow portion constructed on both sides of the capture body in a direction across the river, A capture body comprising a cover unit that covers at least a portion of an opening formed between the upstream unit and the downstream unit.

2. 2. The capture body according to claim 1, wherein the cover unit is provided across an upper end of the upstream unit and an upper end of the downstream unit.

3. 3. The capture body according to claim 1, wherein the cover unit has a first cover portion provided along a direction connecting the upstream unit and the downstream unit.

4. 4. The capture body according to claim 3, wherein the cover unit has a second cover portion provided along a direction intersecting the first cover portion.

5. 5. The capture body according to claim 4, wherein the first cover part and the second cover part are connected to each other.

6. A capture body described in any one of claims 3 to 5, characterized in that a plurality of the first cover portions are provided, and at least some of the first cover portions have one end connected to the upstream unit and the other end connected to the downstream unit.

7. 3. The capture body according to claim 1, wherein the cover unit has a plate material that covers the opening.

8. 3. The trap according to claim 1, wherein the cover unit has a mesh material that covers the opening.

9. the upstream unit is formed by bending a central portion thereof so as to protrude toward the upstream side of the river, A capture body described in any one of claims 1 to 8, characterized in that each end of the upstream unit is attached to a non-overflow section constructed on both sides of the capture body in the direction across the river.

10. A pair of non-overflow sections protruding from both banks of the river, The capture body according to any one of claims 1 to 9, which is provided at an opening between the pair of non-overflow portions; A dam characterized by comprising:

Images