Capture body and weir

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. The downstream unit (7) is formed so that axis line along a longitudinal direction thereof follows regular polygonal trace.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a capturing body and a weir.

Background Art

[0002] As a countermeasure for debris flow in a river, a weir (so-called permeable weir) equipped with a capturing body that captures rocks, driftwood, etc. flowing from upstream is known. The weir has a pair of non-overflow parts protruding from both banks of the river. An opening for water to pass through is provided between the non-overflow parts. The capturing body is provided at the opening, and while allowing small-sized sediment and water to pass through, it captures large-sized rocks, driftwood, etc. The capturing body has an upstream-side unit facing the upstream side in the flow direction of the river and a downstream-side unit facing the downstream side, and both units are inclined and extend so as to approach each other as they go upward, and are connected to each other near their upper end portions. The capturing body is provided across the width direction of the opening, and is attached to a concrete foundation at its lower end (see, for example, Patent Document 1). When debris flow collides with the capturing body, a force that tries to knock down the capturing body to the downstream side acts. The capturing body is configured not to fall by transmitting this force from the lower end to the concrete foundation.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Incidentally, in rivers where large rivers or large amounts of debris flows are predicted, high dams with a height from the concrete foundation to the upper end of 15 m or more are often provided. In the case of a high dam, it is necessary to construct the catching body high as well. However, since the upstream unit and the downstream unit are inclined and extend so as to approach each other upward, the distance between the upper end and the lower end of the catching body along the flowing direction of the river increases as the catching body becomes higher. Therefore, there has been a problem that rocks and driftwood that have overcome the catching body fall toward the lower end of the downstream unit, the downstream unit is damaged, and the force acting on the catching body cannot be transmitted to the concrete foundation.

[0005] Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide a technique in which the catching body is not damaged by rocks and driftwood that have overcome the catching body.

Means for Solving the Problems

[0006] One aspect according to the present invention is a catching body that allows flowing water flowing from the upstream of a river to pass through and catches an object contained in the flowing water. The catching body is provided on the upstream side of the river and includes an upstream unit that catches the object, and is provided on the downstream side of the river and is bent so that the central portion protrudes toward the upstream unit. A downstream unit formed, and a connecting 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 in the direction crossing the river in the catching body, and the downstream unit is formed such that an axis along its longitudinal direction follows a regular polygonal locus.

[0007] Further, it is preferable that the downstream unit is connected with a plurality of cross members, and all angles formed by the axes of the adjacent cross members are equal.

[0008] Further, the downstream unit includes a plurality of vertical members having a first connecting portion for connecting one adjacent horizontal member and a second connecting portion for connecting the other adjacent horizontal member, and it is preferable that all the angles formed by the axis of the first connecting portion and the axis of the second connecting portion are equal.

[0009] Further, it is preferable that a plurality of the first connecting portions and the second connecting portions are provided on one vertical member.

[0010] Further, it is preferable that each horizontal member is formed to have an equal length along the axial direction.

[0011] Further, the upstream unit is bent so that the central portion protrudes toward the upstream side of the river, each end of the upstream unit is attached to the non-overflow portion, and it is preferable that the axis along the longitudinal direction of the upstream unit is formed to follow the locus of a regular polygon.

[0012] Further, the upstream unit has a plurality of horizontal members connected thereto, and it is preferable that all the angles formed by the axes of the adjacent horizontal members are equal.

[0013] Further, the upstream unit includes a plurality of vertical members having a first connecting portion for connecting one adjacent horizontal member and a second connecting portion for connecting the other adjacent horizontal member, and it is preferable that all the angles formed by the axis of the first connecting portion and the axis of the second connecting portion are equal.

[0014] Further, it is preferable that a plurality of the first connecting portions and the second connecting portions are provided on one vertical member.

[0015] Further, it is preferable that each horizontal member is formed to have an equal length along the axial direction.

[0016] One aspect of the present invention is a weir, comprising a pair of non-overflow portions protruding from both banks of a river, respectively, and the above-described capture body provided in an opening between the pair of non-overflow portions.

Effects of the Invention

[0017] According to the present invention, the capture body is not damaged by rocks or driftwood that have overcome the capture body.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Embodiments for Carrying Out the Invention

[0019] Preferred embodiments of the present invention will be described with reference to the drawings.

[0020] <Configuration of the Weir> As shown in FIGS. 1 to 3, the dam 100 is generally called a permeable dam and includes a pair of non-overflow portions 1, an opening 2, a capture body 3, and a gantry 4. In the following, the vertical direction refers to the height direction of the dam 100 (the depth direction of the river), and the horizontal direction refers to the width direction of the dam 100 orthogonal to the height direction of the dam 100 (the width direction of the river).

[0021] The non-overflow portion 1 is, for example, a wall formed of concrete. The pair of non-overflow portions 1 extend from both banks of the river toward the center of the river so as to cross the river. A predetermined interval is provided between the pair of non-overflow portions 1, and an opening 2 is formed. The non-overflow portion 1 is constructed by placing concrete upward on a foundation 11 (see FIG. 7) formed on the riverbed.

[0022] The opening 2 is a space formed between the pair of non-overflow portions 1, and the capture body 3 is installed therein. Thereby, while capturing large rocks and driftwood contained in the debris flow with the capture body 3, water, sand, gravel, etc. are allowed 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 formed of, for example, concrete.

[0023] The capture body 3 allows flowing water flowing from the upstream of the river to pass through and captures objects such as large rocks and driftwood. In the opening 2, it is attached to the foundation 21 of the opening 2 and the side surfaces of the non-overflow portions 1 on both sides in the flowing direction of the river (both sides in the direction crossing the river). The capture body 3 is applied to, for example, a high dam. Here, the "high dam" refers to a dam having a height (dam height) of 15 m or more from the riverbed (bottom) of the river where the foundation of the dam is installed to the upper end of the capture body 3. High dams are mainly provided on large rivers and rivers where a large amount of debris flow is predicted.

[0024] The capture body 3 includes an upstream unit 6, a downstream unit 7, and a connecting unit 8. The upstream unit 6 is provided on the upstream side of the river, and is a functional member that captures objects such as rocks and driftwood contained in the debris flow flowing from the upstream side of the weir 100. That is, the upstream unit 6 is a unit directly affected by the impact of the debris flow. When viewed in plan view of the weir 100, the upstream unit 6 is linearly provided along the direction across the river (the width direction of the weir 100). The upstream unit 6 includes a plurality of vertical members 61 and a plurality of horizontal members 62.

[0025] The plurality of vertical members 61 are provided along the height direction of the weir 100, and the horizontal members 61 adjacent in the height direction are connected. The plurality of vertical members 61 are arranged side by side along the width direction of the weir 100. The interval between adjacent vertical members 61 is preferably smaller than the diameter of the rock to be captured when the debris flow occurs. Also, the interval between adjacent vertical members 61 may be the same throughout from one end to the other end in the width direction of the capture body 3, or the interval may be freely changed according to the assumed scale of the debris flow, such as narrowing the interval only near the center in the width direction of the capture body 3. The vertical member 61 is formed, for example, in a cylindrical shape and is formed from a steel pipe whose axis along the longitudinal direction is a straight line. In the capture body 3, a plurality of vertical members 61 are connected in the longitudinal direction, and each vertical member 61 is connected to each other via a flange portion provided at the longitudinal end. For example, the capture body 3 includes three vertical members 61. Each vertical member 61 may be connected by welding the ends without providing a flange portion, but considering the replacement work after the debris flow collision, connection using a flange portion is preferable.

[0026] Each vertical member 61 is provided with a plurality of connecting portions 63, 64 for connecting to the horizontal member 62 between the longitudinal ends. Specifically, the vertical member 61, which is disposed at the lowermost position in the capture body 3 and whose lower end portion is embedded in the foundation 21 of the opening 2, includes two first connecting portions 63 that connect one adjacent horizontal member 62 between the longitudinal end portions, and two second connecting portions 64 that connect the other adjacent horizontal member 62. The paired first connecting portion 63 and second connecting portion 64 are provided at the same height position. The first connecting portion 63 and the second connecting portion 64 are formed, for example, in a cylindrical shape and are formed from a steel pipe whose axis along the longitudinal direction is a straight line. The first connecting portion 63 and the second connecting portion 64 extend in a direction orthogonal to the longitudinal direction of the vertical member 61, one end is joined to the vertical member 61 by welding or the like, and a flange portion for connecting to the horizontal member 62 is provided at the other end. Note that one end of the first connecting portion 63 and the second connecting portion 64 may be connected to the vertical member 61 via a flange portion. Here, as shown in FIG. 3, the first connecting portion 63 and the second connecting portion 64 are provided on the vertical member 61 such that the angle θ1 formed between their respective axes is all 180 degrees.

[0027] The vertical member 61 disposed in the second stage from the bottom in the capture body 3 includes three first connecting portions 63 that connect one adjacent horizontal member 62 between the longitudinal end portions, and three second connecting portions 64 that connect the other adjacent horizontal member 62. The paired first connecting portion 63 and second connecting portion 64 are provided at the same height position. The first connecting portion 63 and the second connecting portion 64 are formed, for example, in a cylindrical shape and are formed from a steel pipe whose axis along the longitudinal direction is a straight line. The first connecting portion 63 and the second connecting portion 64 extend in a direction orthogonal to the longitudinal direction of the vertical member 61, one end is joined to the vertical member 61 by welding or the like, and a flange portion for connecting to the horizontal member 62 is provided at the other end. Note that one end of the first connecting portion 63 and the second connecting portion 64 may be connected to the vertical member 61 via a flange portion. Here, as shown in FIG. 3, the first connecting portion 63 and the second connecting portion 64 are provided on the vertical member 61 such that the angle θ1 formed between their respective axes is all 180 degrees.

[0028] The vertical member 61 disposed at the uppermost position in the capture body 3 includes five first connecting portions 63 that connect one adjacent cross member 62 between the longitudinal ends, and five second connecting portions 64 that connect the other adjacent cross member 62. The paired first connecting portion 63 and second connecting portion 64 are provided at the same height position. The first connecting portion 63 and the second connecting portion 64 are formed, for example, in a cylindrical shape and are formed from a steel pipe whose axis along the longitudinal direction is a straight line. The first connecting portion 63 and the second connecting portion 64 extend in a direction orthogonal to the longitudinal direction of the vertical member 61, one end is joined to the vertical member 61 by welding or the like, and a flange portion for connecting to the cross member 62 is provided at the other end. Note that one end of the first connecting portion 63 and the second connecting portion 64 may be connected to the vertical member 61 via a flange portion. Here, as shown in FIG. 3, the first connecting portion 63 and the second connecting portion 64 are provided on the vertical member 61 such that the angle θ1 formed by their respective axes is all 180 degrees.

[0029] The plurality of cross members 62 are provided along the direction crossing the river, and are arranged side by side along the height direction of the weir 100. The interval between adjacent cross members 62 is preferably made smaller than the diameter of the rocks to be captured during the occurrence of debris flow. Also, the interval between adjacent cross members 62 may be the same throughout from the upper end to the lower end of the capture body 3, or can be freely changed according to the assumed scale of the debris flow, such as narrowing the interval only above the capture body 3. The cross member 62 is formed, for example, in a cylindrical shape and is formed from a steel pipe whose axis along the longitudinal direction is a straight line. Each cross member 62 is connected to the first connecting portion 63 and the second connecting portion 64 of the vertical member 61 via a flange portion provided at the longitudinal end. Note that each cross member 62 may be connected by welding the ends without providing a flange portion, but considering the replacement work after the debris flow collision, connection using a flange portion is preferred. Among the cross members 62, the cross members 62 arranged on the outermost side in the width direction of the river are attached to the side walls of the non-overflow part 1 with one end in the longitudinal direction facing each other. Specifically, as shown in FIG. 1, the ends of the cross members 62 are connected to the gantry 4, and by embedding this gantry 4 in the non-overflow part 1, each cross member 62 is fixed to the non-overflow part 1.

[0030] The downstream unit 7 is provided on the downstream side of the river as viewed from the upstream unit 6, and the impact load of the debris flow acting on the upstream unit 6 is transmitted through the connecting unit 8 to support the trapping body 3. When the downstream unit 7 is viewed in plan, it is provided along the direction crossing the river, and the central part in its extending direction is bent so as to protrude toward the upstream unit 6. Specifically, when the downstream unit 7 is viewed in plan, its axis along the longitudinal direction is formed so as to follow the locus of a regular polygon. That is, the downstream unit 7 adopts an arch structure and is a structural member that supports the impact load of the debris flow transmitted from the upstream unit 6 through the connecting unit 8 with compressive force. The downstream unit 7 includes a plurality of vertical members 71 and a plurality of cross members 72.

[0031] The plurality of vertical members 71 are provided along the height direction of the weir 100, and the adjacent cross members 71 in the height direction are connected. The plurality of vertical members 71 are arranged side by side along the width direction of the weir 100. The interval between adjacent vertical members 71 is preferably made smaller than the diameter of the rocks to be trapped when a debris flow occurs. Also, the interval between adjacent vertical members 71 may be the same throughout the width direction from one end to the other end of the trapping body 3, or can be freely changed according to the assumed scale of the debris flow, such as narrowing the interval only near the center in the width direction of the trapping body 3. The vertical member 71 is formed of, for example, a steel pipe that is formed in a cylindrical shape and has a straight axis along the longitudinal direction. In the capturing body 3, a plurality of vertical members 71 are connected in the longitudinal direction, and each vertical member 71 is connected to each other via flange portions provided at the longitudinal ends. For example, as shown in FIGS. 4 to 6, the capturing body 3 includes three vertical members 71. Note that each vertical member 71 may be connected at its ends by welding without providing flange portions, but considering the replacement work after a debris flow collision, connection using flange portions is preferred.

[0032] Each vertical member 71 includes a plurality of connecting portions 73 and 74 that connect to a cross member 72 between the longitudinal ends. Specifically, as shown in FIG. 4, the vertical member 71 that is disposed at the lowest position in the capturing body 3 and whose lower end is buried in the foundation 21 of the opening 2 includes, between the longitudinal ends, two first connecting portions 73 that connect one adjacent cross member 72 and two second connecting portions 74 that connect the other adjacent cross member 72. The paired first connecting portion 73 and second connecting portion 74 are provided at the same height position. The first connecting portion 73 and the second connecting portion 74 are formed of, for example, a steel pipe that is formed in a cylindrical shape and has a straight axis along the longitudinal direction. The first connecting portion 73 and the second connecting portion 74 extend in a direction orthogonal to the longitudinal direction of the vertical member 71, one end is joined to the vertical member 71 by welding or the like, and a flange portion for connecting to the cross member 72 is provided at the other end. Note that one end of the first connecting portion 73 and the second connecting portion 74 may be connected to the vertical member 71 via a flange portion. Here, the first connecting portion 73 and the second connecting portion 74 are provided on the vertical member 71 such that the angle θ2 formed by their respective axes is the same angle (for example, about 165 degrees). Also, the first connecting portion 73 and the second connecting portion 74 are formed such that the lengths along the longitudinal direction are all the same length.

[0033] As shown in FIG. 5, the vertical member 71 disposed in the second stage from the bottom in the capture body 3 includes three first connecting portions 73 that connect one adjacent cross member 72 between the longitudinal ends, and three second connecting portions 74 that connect the other adjacent cross member 72. The paired first connecting portion 73 and second connecting portion 74 are provided at the same height. The first connecting portion 73 and the second connecting portion 74 are formed, for example, in a cylindrical shape and are formed from a steel pipe whose axis along the longitudinal direction is a straight line. The first connecting portion 73 and the second connecting portion 74 extend in a direction orthogonal to the longitudinal direction of the vertical member 71, one end is joined to the vertical member 71 by welding or the like, and a flange portion for connecting to the cross member 72 is provided at the other end. Note that one end of the first connecting portion 73 and the second connecting portion 74 may be connected to the vertical member 71 via a flange portion. Here, the first connecting portion 73 and the second connecting portion 74 are provided on the vertical member 71 such that the angles θ2 formed by their respective axes are all the same angle (for example, about 165 degrees). Further, the first connecting portion 73 and the second connecting portion 74 are formed such that their lengths along the longitudinal direction are all the same.

[0034] As shown in FIG. 6, the vertical member 71 disposed at the uppermost position in the capture body 3 includes five first connecting portions 73 that connect one adjacent cross member 72 between the longitudinal ends, and five second connecting portions 74 that connect the other adjacent cross member 72. The paired first connecting portion 73 and second connecting portion 74 are provided at the same height. The first connecting portion 73 and the second connecting portion 74 are formed, for example, in a cylindrical shape and are formed from a steel pipe whose axis along the longitudinal direction is a straight line. The first connecting portion 73 and the second connecting portion 74 extend in a direction orthogonal to the longitudinal direction of the vertical member 71, one end is joined to the vertical member 71 by welding or the like, and a flange portion for connecting to the cross member 72 is provided at the other end. Note that one end of the first connecting portion 73 and the second connecting portion 74 may be connected to the vertical member 71 via a flange portion. Here, the first connecting portion 73 and the second connecting portion 74 are provided on the vertical member 71 such that the angle θ2 formed between their respective axes is the same angle (for example, about 165 degrees). Also, the first connecting portion 73 and the second connecting portion 74 are formed such that their lengths along the longitudinal direction are all the same length.

[0035] The plurality of horizontal members 72 are provided along the direction crossing the river, and are arranged side by side along the height direction of the weir 100. The interval between adjacent horizontal members 72 is preferably made smaller than the diameter of the rocks to be captured when a debris flow occurs. Also, the interval between adjacent horizontal members 72 may be the same throughout from the upper end to the lower end of the capture body 3, or can be freely changed according to the assumed scale of the debris flow, such as narrowing the interval only above the capture body 3. The horizontal member 72 is provided at a position facing the horizontal member 62 of the upstream unit 6 in the flow direction of the river. The horizontal member 72 is formed, for example, in a cylindrical shape and is formed from a steel pipe whose axis along the longitudinal direction is a straight line. Each horizontal member 72 is connected to the first connecting portion 73 and the second connecting portion 74 of the vertical member 71 via flange portions provided at the longitudinal ends. Since each horizontal member 72 is required to have a function of receiving the impact load of the debris flow, it is preferable to use a steel pipe with a larger diameter and higher strength than the steel pipe constituting the horizontal member 62 of the upstream unit 6. Note that each horizontal member 72 may be connected by welding the ends to each other without providing flange portions, but considering the replacement work after the debris flow collision, the connection using flange portions is preferable. Among the horizontal members 72, the horizontal member 72 arranged on the outermost side in the width direction of the river has one longitudinal end attached to the side wall of the non-overflow portion 1 facing each other. Specifically, as shown in FIG. 1, the end of the horizontal member 72 is connected to the gantry 4, and by embedding this gantry 4 in the non-overflow portion 1, each horizontal member 72 is fixed to the non-overflow portion 1.

[0036] Among the downstream units 7, the cross member 72 disposed at the central portion in the extending direction (axial direction) of the cross member 72 is located closest to the cross member 62 of the most upstream unit 6, and is located farther away from the cross member 62 of the upstream unit 6 as it approaches the end of the cross member 72. By connecting the cross members 72 to each other so as to have such an arrangement, the downstream unit 7 can be formed in an arch shape. Further, the cross member 72 is formed such that the lengths along the longitudinal direction are all the same length. Therefore, in the downstream unit 7, the cross members 72, the first connecting portions 73, and the second connecting portions 74 connected to the respective vertical members 71 are all formed to have the same size. Furthermore, since the angles θ2 formed by the axes of the first connecting portion 73 and the second connecting portion 74 provided on the vertical member 71 are all the same angle (for example, about 165 degrees), the angles θ2 formed by the axes of the adjacent cross members 72 connected to the first connecting portion 73 and the second connecting portion 74 are all equal.

[0037] The connecting unit 8 connects the upstream unit 6 and the downstream unit 7. The connecting unit 8 is provided along the flow direction of the river, and connects the vertical member 61 of the upstream unit 6 and the vertical member 71 of the downstream unit 7 facing each other. That is, the connecting unit 8 is arranged side by side along the height direction of the weir 100, similarly to the cross members 62 and 72. Therefore, the interval between adjacent connecting units 8 is provided to be smaller than the diameter of the rocks to be captured during the occurrence of debris flow. Also, the interval between adjacent connecting units 8 may be the same throughout from the upper end to the lower end of the capture body 3, similarly to the cross members 62 and 72, or can be freely changed according to the assumed scale of the debris flow, such as narrowing the interval only above the capture body 3. The connecting unit 8 is formed, for example, of a steel pipe that is formed in a cylindrical shape and has a straight axis along the longitudinal direction. One end of the connecting unit 8 is connected to the vertical member 61 of the upstream unit 6 via a flange portion, and the other end is connected to the vertical member 71 of the downstream unit 7 via a flange portion. Also, at the uppermost ends of the upstream unit 6 and the downstream unit 7, in addition to connecting the vertical members 61 and 71, one end of the connecting unit 8 is connected to the horizontal member 62 of the upstream unit 6, and the other end is connected to the horizontal member 72 of the downstream unit 7. Note that the connecting unit 8 is not necessarily limited to connection using a flange portion, and may be joined by welding or the like.

[0038] The pedestal 4 is erected on the foundation 11 of the non-overflow portion 1. The pedestal 4 is connected to the capture body 3 and, when the weir 100 is completed, is embedded in the non-overflow portion 1 while being connected to the capture body 3. The pedestal 4 is used to firmly fix the capture body 3 to the non-overflow portion 1. The pedestal 4 is provided at positions facing the end of the horizontal member 62 of the upstream unit 6 and at positions facing the end of the horizontal member 72 of the downstream unit 7 for each non-overflow portion 1. A plurality of pedestals 4 are connected along the height direction of the non-overflow portion 1 and are provided at positions where each horizontal member 62, 72 of the capture body 3 can be connected. The pedestal 4 includes a plurality of vertical portions 41 and a plurality of horizontal portions 42.

[0039] The plurality of vertical portions 41 are provided along the height direction of the weir 100. The vertical portion 41 is formed, for example, of a steel pipe that is formed in a cylindrical shape and has a straight axis along the longitudinal direction. Flange portions are provided at both ends of the vertical portion 41. The axial direction ends of each vertical portion 41 are connected to each other via the flange portions. The lowermost arranged vertical portion 41 is directly provided on the foundation 11 (see FIG. 7) of the non-overflow portion 1 and is embedded in the foundation 11. As a result, the lower end portion of the pedestal 4 is erected on the foundation 11.

[0040] A plurality of horizontal portions 42 are provided so as to intersect (orthogonally) the vertical portion 41 in the axial direction of the vertical portion 41 and are arranged side by side along the height direction of the weir 100. The horizontal portion 42 is formed, for example, in a cylindrical shape and is formed from a steel pipe whose axis along the longitudinal direction is a straight line. Each horizontal portion 42 is connected to the horizontal members 62 and 72 of the capturing body 3 via a flange portion provided at one end in the axial direction thereof. Each horizontal portion 42 is provided so as to penetrate a part of the vertical portion 41 and is joined to the vertical portion 41 at the intersection portion. That is, the gantry 4 is configured as an integrated intersection pipe that is formed by joining the steel pipe constituting the vertical portion 41 and the steel pipe constituting the horizontal portion 42 to each other and having a substantially cross-shaped front view. One end in the longitudinal direction of each horizontal portion 42 is provided so as to be exposed from the non-overflow portion 1 to the opening portion 2, and is arranged so as to be connectable to the horizontal members 62 and 72 at this one end. The gantry 4 is buried in the non-overflow portion 1 except for the connection portions with the horizontal members 62 and 72 of the capturing body 3 in the horizontal portion 42. By burying the gantry 4 in the non-overflow portion 1, the ends of the respective horizontal members 62 and 72 are fixed to the non-overflow portion 1 via the gantry 4, and the capturing body 3 is fixed to the side wall of the non-overflow portion 1. The gantry 4 extends in the height direction of the non-overflow portion 1 by connecting a plurality of ends of the vertical portions 41 to each other.

[0041] <Method of constructing a weir> Next, a method of constructing the weir 100 will be described. When constructing the weir 100, as shown in FIG. 7, while standing the vertical members 61 on the foundation 21 from the vicinity of the center in the width direction of the opening portion 2 toward the non-overflow portions 1 on both banks, the adjacent vertical members 61 are connected by the horizontal members 62 and assembled. The horizontal member 62 is connected to the vertical member 61 by connecting to the first connection portion 63 and the second connection portion 64 provided on the vertical member 61. Also, for the downstream unit 7, similar to the upstream unit 6, as shown in Fig. 7, while erecting the vertical members 71 on the foundation 21 from near the center in the width direction of the opening 2 towards the non-overflow portions 1 on both banks, the adjacent vertical members 71 are connected by the horizontal members 72 and assembled. The horizontal member 72 is connected to the vertical member 71 by connecting to the first connecting portion 73 and the second connecting portion 74 provided on the vertical member 71. Further, the vertical member 61 of the upstream unit 6 and the vertical member 71 of the downstream unit 7 are connected by the connecting unit 8 (the first step).

[0042] The erection of the vertical members 61 and 71 on the foundation 21, the connection of the horizontal members 62 and 72, and the connection of the vertical member 61 of the upstream unit 6 and the vertical member 71 of the downstream unit 7 by the connecting unit 8 are repeated. As shown in Fig. 8, when the ends of the horizontal members 62 and 72 respectively approach just before the construction area of the non-overflow portion 1, the gantry 4 is erected on the foundation 11 of the non-overflow portion 1 (the second step).

[0043] After erecting the gantry 4 on the foundation 11 of the non-overflow portion 1, as shown in Fig. 9, the connecting portions 63, 64, 73, 74 of the vertical members 61 and 71 provided up to the position adjacent to the non-overflow portion 1 and the ends of the horizontal portion 42 of the gantry 4 are connected by the horizontal members 62 and 72. Here, one end of the horizontal member 62 and 72 is connected to the connecting portions 63, 64, 73, 74 via the flange portion, and the other end of the horizontal member 62 and 72 is connected to the horizontal portion 42 of the gantry 4 via the flange portion (the third step). Thereby, the lowermost part of the capture body 3 is completed, and the horizontal member 62 at this lowermost stage is connected to the gantry 4.

[0044] Next, as shown in Fig. 10, concrete is placed on the foundation 11 of the non-overflow portion 1 to construct the non-overflow portion 1 (the fourth step). Here, the concrete is placed on the foundation 11 of the non-overflow portion 1 so that the flange portion at the upper end of the vertical portion 41 arranged at the uppermost part of the constructed gantry 4 and the flange portion of the horizontal portion 42 of the constructed gantry 4 are exposed, and most of the gantry 4 is buried in the non-overflow portion 1. Note that the fourth step may be performed after repeating the first to third steps a plurality of additional times. That is, after connecting the vertical members 61, 71, the horizontal members 62, 72, and the gantry 4 in a plurality of additional tiers, concrete may be placed in the foundation 11 of the non-overflow portion 1 to construct the non-overflow portion 1.

[0045] Also, simultaneously with the construction of the non-overflow portion 1 in the fourth step, or before or after the construction of the non-overflow portion 1, concrete is placed in the foundation 21 of the opening 2 to embed the lower ends of the vertical members 61, 71 in the concrete.

[0046] Next, as shown in FIG. 11, the first to third steps are repeated to connect a second vertical member 61, 71 to the vertical members 61, 71 already erected on the foundation 21. That is, while connecting a new vertical member 61, 71 to the upper end of the lowermost vertical member 61, 71, the adjacent vertical members 61, 71 are connected by the horizontal members 62, 72. Further, the vertical member 61 and the vertical member 71 are connected by the connecting unit 8. Then, when the ends of the horizontal members 62, 72 each approach the construction area of the non-overflow portion 1 just before, a new vertical portion 41 of the gantry 4 is connected to the upper end of the vertical portion 41 of the gantry 4. Thereafter, the connecting portions 63, 64, 73, 74 of the vertical members 61, 71 provided up to the position adjacent to the non-overflow portion 1 and the horizontal portion 42 of the gantry 4 are connected by the horizontal members 62, 72. Thereafter, concrete is placed on the upper end surface of the non-overflow portion 1 to construct the non-overflow portion 1. Here, on the upper end surface of the non-overflow portion 1, concrete is placed so that the flange portion of the upper end of the uppermost vertical portion 41 of the constructed gantry 4 and the flange portion of the horizontal portion 42 of the constructed gantry 4 are exposed, and most of the gantry 4 is embedded in the non-overflow portion 1.

[0047] Next, the first to third steps are repeated to connect a third vertical member 61, 71 to the second vertical member 61, 71. That is, while connecting a new vertical member 61, 71 to the upper end of the second-stage vertical member 61, 71, the adjacent vertical members 61, 71 are connected by the horizontal members 62, 72. Further, the vertical member 61 and the vertical member 71 are connected by the connecting unit 8, and the opposing horizontal members 62 and 72 arranged at the uppermost end are connected by the connecting unit 8. Then, when the ends of the horizontal members 62 and 72 approach the construction area of the non-overflow part 1 respectively until just before, a new vertical part 41 of the gantry 4 is connected to the upper end of the vertical part 41 of the gantry 4. Then, the connecting parts 63, 64, 73, 74 of the vertical members 61, 71 provided up to the position adjacent to the non-overflow part 1 and the horizontal part 42 of the gantry 4 are connected by the horizontal members 62, 72. Thereafter, concrete is placed on the upper end surface of the non-overflow part 1 to construct the non-overflow part 1. Here, the concrete is placed so that the upper end part of the vertical part 41 arranged at the uppermost part of the constructed gantry 4 is completely hidden and the flange part of the horizontal part 42 of the constructed gantry 4 is exposed on the upper end surface of the non-overflow part 1, and most of the gantry 4 is buried in the non-overflow part 1. With the above steps, a weir 100 as shown in FIG. 12 is constructed.

[0048] According to the weir 100 as described above, since the horizontal member 72 constituting the downstream unit 7 is attached to the non-overflow part 1, even if the rocks and driftwood contained in the debris flow cross over the upper ends of the upstream unit 6 and the downstream unit 7 and fall below the catching body 3, the fallen rocks and driftwood are less likely to collide with the catching body 3, and damage to the catching body 3 can be suppressed. Also, since the vertical member 71 is erected along the arrangement direction of the horizontal members 72 (the height direction of the catching body 3), the vertical member 71 does not protrude downstream from the horizontal member 72 and the fallen rocks and the like do not collide with it. In addition, since the downstream unit 7 is formed such that the axis along its longitudinal direction follows the locus of a regular polygon, all the angles θ2 formed by the axes of the adjacent horizontal members 72 are equal. Thereby, the angle θ2 formed by the first connecting part 73 and the second connecting part 74 in the vertical member 71 can be made equal, so that the first connecting part 73 and the second connecting part 74 connected to the vertical member 71 can be made common. Along with this, the horizontal members 72 connecting the vertical members 71 to each other can also be made the same length, so that the horizontal members 72 constituting the downstream unit 7 can be made common. Therefore, it is not necessary to manufacture many types of the vertical members 71 and the horizontal members 72, so that the manufacturing cost can be reduced, the quality can be improved, the manufacturing efficiency can be improved, and the inventory management can be simplified. Further, by sharing the first connecting portion 73 and the second connecting portion 74, a plurality of first connecting portions 73 and second connecting portions 74 can be provided on the same vertical member 71, the vertical member 71 can be lengthened, and the number of connecting points of the vertical member 71 can be reduced.

[0049] Further, since the trapping body 3 is connected to the pedestal 4 embedded in the concrete constructing the non-overflow portion 1, the trapping body 3 is firmly fixed to the non-overflow portion 1. Thereby, a part of the load of the debris flow acting on the trapping body 3 can be released to the non-overflow portion 1, and the strength against the pushing-out or pulling-out of the trapping body 3 is improved. Further, since the pedestal 4 has a simple structure of a vertical portion 41 and a horizontal portion 42 both formed of steel pipes, the same members as the vertical members 61, 71 and the horizontal members 62, 72 of the trapping body 3 can be used, and the connecting work can be easily performed.

[0050] <Modification> Further, a levee 200 provided with a trapping body 3A as shown in FIGS. 13 and 14 may be used. The trapping body 3A is obtained by changing the configuration of the upstream unit 6 in the trapping body 3 shown in FIGS. 1 to 6 to an upstream unit 6A. Hereinafter, the upstream unit 6A, which is the difference between the trapping body 3A and the trapping body 3, will be described. As shown in FIGS. 13 and 14, the trapping body 3A includes an upstream unit 6A, a downstream unit 7A, and a connecting unit 8A. The upstream unit 6A is provided on the upstream side of the river and captures objects such as rocks and driftwood contained in the debris flow flowing from the upstream side of the levee 200. That is, the upstream unit 6A is a unit on which the impact of the debris flow directly acts. When viewed in plan, the upstream unit 6A is provided along the direction crossing the river, and is formed by bending such that the central portion in its extending direction protrudes toward the upstream of the river. Specifically, when viewed in plan, the upstream unit 6A is formed such that the axis along its longitudinal direction follows the locus of a regular polygon. That is, the upstream unit 6A adopts a curved arch structure, and has a structure in which the combined stress degree with respect to the temperature stress of the upstream unit 6A (the internal stress generated in the structure due to temperature change (for example, the stress associated with the expansion and contraction of each component due to the change in the outside air temperature, etc.)) is reduced. The upstream unit 6A is configured by connecting a plurality of vertical members 61 and a plurality of horizontal members 62.

[0051] The plurality of vertical members 61 are provided along the height direction of the weir 200, and are connected to the horizontal members 62 adjacent in the height direction. The plurality of vertical members 61 are arranged side by side along the width direction of the weir 200. It is preferable that the interval between adjacent vertical members 61 is smaller than the diameter of the rocks to be captured when a debris flow occurs. Also, the interval between adjacent vertical members 61 may be the same throughout from one end to the other end in the width direction of the capture body 3A, or can be freely changed according to the assumed scale of the debris flow, such as narrowing the interval only near the center in the width direction of the capture body 3A. The vertical member 61 is formed, for example, in a cylindrical shape and is formed from a steel pipe whose axis along the longitudinal direction is a straight line. In the capture body 3A, a plurality of vertical members 61 are connected in the longitudinal direction, and each vertical member 61 is connected to each other via flange portions provided at the longitudinal ends. For example, as shown in FIG. 13, the capture body 3A includes three vertical members 61. Each vertical member 61 may be connected by welding the ends to each other without providing flange portions, but considering the replacement work after a debris flow collision, connection using flange portions is preferable.

[0052] Each vertical member 61 is provided with a plurality of connecting portions 63, 64 for connecting to the horizontal member 62 between the longitudinal ends. Specifically, the vertical member 61, which is disposed at the lowermost position in the capture body 3A and whose lower end is embedded in the foundation 21 of the opening 2, includes two first connecting portions 63 that connect one adjacent cross member 62 between the longitudinal ends, and two second connecting portions 64 that connect the other adjacent cross member 62. The paired first connecting portion 63 and second connecting portion 64 are provided at the same height position. The first connecting portion 63 and the second connecting portion 64 are, for example, formed in a cylindrical shape and are formed from a steel pipe whose axis along the longitudinal direction is a straight line. The first connecting portion 63 and the second connecting portion 64 extend in a direction orthogonal to the longitudinal direction of the vertical member 61, one end is joined to the vertical member 61 by welding or the like, and a flange portion for connecting to the cross member 62 is provided at the other end. Note that one end of the first connecting portion 63 and the second connecting portion 64 may be connected to the vertical member 61 via a flange portion. Here, as shown in FIG. 14, the first connecting portion 63 and the second connecting portion 64 are provided on the vertical member 61 such that the angle θ3 formed by their respective axes is the same angle (for example, about 165 degrees). Further, the first connecting portion 63 and the second connecting portion 64 are formed such that their lengths along the longitudinal direction are all the same length.

[0053] The vertical member 61 disposed in the second stage from the bottom in the capture body 3A includes three first connecting portions 63 that connect one adjacent cross member 62 between the longitudinal ends, and three second connecting portions 64 that connect the other adjacent cross member 62. The paired first connecting portion 63 and second connecting portion 64 are provided at the same height position. The first connecting portion 63 and the second connecting portion 64 are, for example, formed in a cylindrical shape and are formed from a steel pipe whose axis along the longitudinal direction is a straight line. The first connecting portion 63 and the second connecting portion 64 extend in a direction orthogonal to the longitudinal direction of the vertical member 61, one end is joined to the vertical member 61 by welding or the like, and a flange portion for connecting to the cross member 62 is provided at the other end. Note that one end of the first connecting portion 63 and the second connecting portion 64 may be connected to the vertical member 61 via a flange portion. Here, the first connecting part 63 and the second connecting part 64 are provided on the vertical member 61 such that the angle θ3 formed between their respective axes is the same angle (for example, about 165 degrees). Also, the first connecting part 63 and the second connecting part 64 are formed such that their lengths along the longitudinal direction are all the same length.

[0054] The vertical member 61 disposed at the uppermost position in the capturing body 3A includes five first connecting parts 63 that connect one adjacent cross member 62 between the longitudinal ends, and five second connecting parts 64 that connect the other adjacent cross member 62. The paired first connecting part 63 and second connecting part 64 are provided at the same height position. The first connecting part 63 and the second connecting part 64 are formed, for example, in a cylindrical shape and are formed from a steel pipe whose axis along the longitudinal direction is a straight line. The first connecting part 63 and the second connecting part 64 extend in a direction orthogonal to the longitudinal direction of the vertical member 61, one end is joined to the vertical member 61 by welding or the like, and a flange part for connecting to the cross member 62 is provided at the other end. Note that one end of the first connecting part 63 and the second connecting part 64 may be connected to the vertical member 61 via a flange part. Here, the first connecting part 63 and the second connecting part 64 are provided on the vertical member 61 such that the angle θ3 formed between their respective axes is the same angle (for example, about 165 degrees). Also, the first connecting part 63 and the second connecting part 64 are formed such that their lengths along the longitudinal direction are all the same length.

[0055] The plurality of cross members 62 are provided along the direction crossing the river, and are arranged side by side along the height direction of the weir 200. It is preferable that the interval between adjacent cross members 62 is made smaller than the diameter of the rocks to be captured when a debris flow occurs. Also, the interval between adjacent cross members 62 may be the same throughout from the upper end to the lower end of the capturing body 3A, or can be freely changed according to the assumed scale of the debris flow, such as narrowing the interval only above the capturing body 3A as shown in FIG. 13. The cross member 62 is provided at a position facing the cross member 72 of the downstream unit 7A in the flow direction of the river. The cross member 62 is formed, for example, in a cylindrical shape and is made of a steel pipe whose axis along the longitudinal direction is a straight line. Each cross member 62 is connected to the first connecting portion 63 and the second connecting portion 64 of the vertical member 61 via flange portions provided at the longitudinal ends. Note that each cross member 62 may be connected by welding the ends to each other without providing flange portions. However, considering the replacement work after a debris flow collision, connection using flange portions is preferred. Also, the first connecting portion 63 and the second connecting portion 64 are attached to the vertical member 61 at a predetermined angle with respect to the axis so that the cross member 62 forms an arch shape. The degree of bending of the beam portion connecting the cross members 62 is determined by the number of cross members 62 and the width of the capture body 3A. Among the cross members 62, the cross members 62 arranged on the outermost side in the river width direction have one longitudinal end attached to the side walls of the non-overflow portion 1 facing each other. Specifically, as shown in FIG. 9, the ends of the cross member 62 are connected to the gantry 4, and by embedding this gantry 4 in the non-overflow portion 1, each cross member 62 is fixed to the non-overflow portion 1. Note that since the configuration of the gantry 4 is the same as the configuration shown in FIG. 1 described above, the description is omitted.

[0056] The downstream unit 7A is provided on the downstream side 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. The downstream unit 7A is provided along the direction crossing the river when the weir 200 is viewed in plan, and is bent so that the central portion in its extending direction protrudes toward the upstream unit 6A. That is, the downstream unit 7A employs a curved arch structure and is a structural member that supports the impact load of the debris flow transmitted from the upstream unit 6A via the connecting unit 8A with a compressive force. The downstream unit 7A is configured by connecting a plurality of vertical members 71 and a plurality of cross members 72. Incidentally, since the configuration of the downstream unit 7A is the same as that of the downstream unit 7 in the above-described embodiment, a detailed description thereof will be omitted. As shown in FIG. 14, the first connecting portions 73 and the second connecting portions 74 provided on each vertical member 71 are provided on the vertical member 71 such that the angles θ4 formed by their respective axes are all the same angle (for example, about 165 degrees). Further, the first connecting portion 73 and the second connecting portion 74 are formed such that their lengths along the longitudinal direction are all the same length.

[0057] The connected horizontal members 62 and 72 are bent so that the central portion in their extending direction (the axial direction of the horizontal members 62 and 72) protrudes most toward the upstream side of the river and are formed in an arch shape. When viewed in plan, the horizontal members 62 and 72 facing each other in the flow direction of the river are provided at substantially equal intervals from one end to the other end. That is, the horizontal members 62 and 72 facing each other along the flow direction of the river are connected by a plurality of connecting units 8A of the same length. Each vertical member 61 connects the horizontal members 62 to each other, and each vertical member 71 connects the horizontal members 72 to each other. Further, the horizontal members 62 and 72 are formed such that their lengths along the longitudinal direction are all the same length. Therefore, in the upstream unit 6A and the downstream unit 7A, the horizontal members 62 and 72 connected to the respective vertical members 61 and 71, the first connecting portions 63 and 73, and the second connecting portions 64 and 74 are all formed to have the same size. Furthermore, since the angles θ3 and θ4 formed by the respective axes of the first connecting portions 63 and 73 and the second connecting portions 64 and 74 provided on the vertical members 61 and 71 are all the same angle (for example, about 165 degrees), the angles θ3 and θ4 formed by the axes of the adjacent horizontal members 62 and 72 connected to the first connecting portions 63 and 73 and the second connecting portions 64 and 74 are all equal.

[0058] The connecting unit 8A connects the upstream unit 6A and the downstream unit 7A. The connecting unit 8A is provided along the flow direction of the river, and connects the vertical member 61 of the upstream unit 6A and the vertical member 71 of the downstream unit 7A that face each other. Note that since the configuration of the connecting unit 8A is the same as that of the connecting unit 8 in the above embodiment, the description thereof is omitted.

[0059] As described above, according to the dam 200, in addition to exhibiting the same effects as the dam 100, since the upstream unit 6A is fixed to the non-overflow portion 1, the impact load due to the debris flow can be released to the non-overflow portion 1. At this time, considering the thermal stress, when the upstream unit 6A is formed linearly, the combined stress degree becomes large. The higher and wider the dam is, like a high dam, the greater the thermal stress becomes. However, as in the capture body 3A shown in FIGS. 13 to 14, since the upstream unit 6A is formed by bending, even when both ends are fixed to the non-overflow portion 1 via the gantry 4, the combined stress degree with respect to the thermal stress can be reduced. As a result, while increasing the strength of the dam 200, the combined stress degree with respect to the thermal stress can be reduced, and the steel pipe diameter of the upstream unit 6A can also be reduced. In addition, by arranging the upstream unit 6A and the downstream unit 7A at equal intervals over the entire width direction of the capture body 3A and making the angles formed by the first connecting portions 63, 73 and the second connecting portions 64, 74 equal, the vertical members 61, 71, the horizontal members 62, 72, the first connecting portions 63, 73, and the second connecting portions 64, 74 of the upstream unit 6A and the downstream unit 7A can be made common, and the connecting unit 8A can be made common. Along with this, it is also possible to easily install a cover member that connects the upper ends of the upstream unit 6A and the downstream unit 7A to prevent rocks and driftwood from falling between the upstream unit 6A and the downstream unit 7A.

[0060] <Others> Although the preferred embodiments of the present invention have been described, the present invention is not limited to the above-described embodiments, and includes all aspects included in the concept and scope of claims of the present invention. Also, each configuration may be selectively combined as appropriate so as to achieve at least a part of the above-described problems and effects. For example, the shape, material, arrangement, size, etc. of each component in the above-described embodiments may be appropriately changed according to the specific usage mode of the present invention. For example, the downstream unit 7 of the capture body 3 may be formed such that the axis along its longitudinal direction follows an arc trajectory. In this case, the first connecting portion 73, the second connecting portion 74, and the cross member 72 need to be formed with the same curvature. In addition, although an example in which the capture body 3 is provided on the weir 100 called a high dam has been described, it may be provided on a weir other than a high dam.

Explanation of Reference Numerals

[0061] 1 Non-overflow portion 11 Foundation 2 Opening 21 Foundation 3, 3A Capture body 4 Stand 41 Vertical portion 42 Horizontal portion 6, 6A Upstream unit 61 Vertical member 62 Horizontal member 63 First connecting portion 64 Second connecting portion 7, 7A Downstream unit 71 Vertical member 72 Horizontal member 73 First connecting portion 74 Second connecting portion 8, 8A Connecting unit 100, 200 Weir

Claims

1. A capturing body that allows flowing water to flow from the upper reaches of a river and captures objects contained in the flowing water, An upstream unit provided on the upstream side of the river for capturing the object, A downstream unit provided on the downstream side of the river and formed by bending so that the central part protrudes toward the upstream unit, A connecting unit that connects the upstream unit and the downstream unit, Each end of the downstream unit is attached to non-overflow portions constructed on both sides in the direction crossing the river in the capturing body, The downstream unit is characterized in that the axis along its longitudinal direction is formed to follow a regular polygon locus.

2. The downstream unit has a plurality of cross members connected thereto, The capturing body according to claim 1, wherein all angles formed by the axes of adjacent cross members are equal.

3. The downstream unit includes a plurality of longitudinal members having a first connecting portion that connects one adjacent cross member and a second connecting portion that connects the other adjacent cross member, The capturing body according to claim 2, wherein all angles formed by the axis of the first connecting portion and the axis of the second connecting portion are equal.

4. The capturing body according to claim 3, wherein a plurality of the first connecting portions and the second connecting portions are provided on one longitudinal member.

5. The capturing body according to any one of claims 2 to 4, wherein each cross member is formed to have an equal length along the axial direction.

6. The upstream unit is formed by bending so that the central part protrudes toward the upstream side of the river, Each end of the upstream unit is attached to the non-overflow portion, The capturing body according to any one of claims 1 to 5, wherein the axis along its longitudinal direction is formed to follow a regular polygon locus.

7. The upstream unit has a plurality of cross members connected thereto, The capturing body according to claim 6, wherein all angles formed by the axes of adjacent cross members are equal.

8. The upstream unit includes a plurality of longitudinal members having a first connecting portion that connects one adjacent cross member and a second connecting portion that connects the other adjacent cross member, The capturing body according to claim 7, wherein all angles formed by the axis of the first connecting portion and the axis of the second connecting portion are equal.

9. The capture body according to claim 8, wherein a plurality of the first connecting portions and the second connecting portions are provided on one vertical member.

10. The capture body according to any one of claims 7 to 9, wherein each cross member is formed to have an equal length along the axial direction.

11. A pair of non-overflow portions protruding from both banks of a river, The capture body according to any one of claims 1 to 10, provided in an opening between the pair of non-overflow portions, A weir comprising the same.

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