Dams and dam construction methods

Abstract

The present invention provides a weir in which gaps are less likely to occur at the fixing points between the trapping body and the weir body, and a method for constructing such a weir. [Solution] The weir 1 comprises a weir body 2, a capture body 3 fixed to the upstream surface 23 of the weir body 2, and a fixing part 4 that fixes the capture body 3 to the upstream surface 23. The capture body 3 includes a capture part 304, a plurality of legs, and a first plate-shaped member BM1 attached to the ends of the plurality of legs. Each of the fixing structures 41 of the fixing part 4 includes a second plate-shaped member BM2 that is in surface contact with the first plate-shaped member BM1, four first holding parts 411 that penetrate the vicinity of each corner of the second plate-shaped member BM2 and are cast into the upstream surface 23, and hold the second plate-shaped member BM2 spaced apart from the upstream surface 23 so that the second plate-shaped member BM2 is parallel to the upstream surface 23, a plurality of second holding parts 412 that maintain surface contact between the first plate-shaped member BM1 and the second plate-shaped member BM2, and a filling part 413 that fills the gap Ga between the second plate-shaped member BM2 and the upstream surface 23.

Description

Technical Field

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[0001] The present invention relates to a dike and a method for constructing a dike, and more specifically, to a dike provided in a river and a method for constructing the dike.

Background Art

[0002] In recent years, damage caused by driftwood contained in debris flows has been increasing, and it has become important to prevent driftwood disasters. Therefore, as one of the countermeasures, attempts have been made to enhance the driftwood capture effect of existing impermeable sand dikes (hereinafter sometimes referred to as "dike bodies"). As this attempt, a dike in which a driftwood capture structure is installed on the upstream side of a sand dike is known (see, for example, Patent Document 1). In the dike described in Patent Document 1, the driftwood capture structure is fixed to the upstream side wall surface portion of the sand dike by anchor bolts via a base plate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When anchor bolts are driven through a base plate on the upstream side wall surface portion (upstream surface) of a sand dike (dike body) as in the dike of Patent Document 1, the upstream surface has unevenness and often has a non-uniform slope, so a gap may occur between the base plate of the driftwood capture structure (hereinafter sometimes referred to as "capture body") and the upstream surface.

[0005] Therefore, it is conceivable to pour additional concrete with good slope accuracy onto the upstream face of the dam body and fix the base plate to that slope. However, even when using this method, gaps may occur between the dam body and the trapping body due to manufacturing errors of the trapping body or installation errors when installing the trapping body on the slope.

[0006] The present invention has been made in view of the above points, and one of its objectives is to provide a weir in which gaps are less likely to occur at the fixing points between the capture body and the weir body, and a method for constructing the weir. [Means for solving the problem]

[0007] (1) The weir according to the present invention comprises a weir body arranged across a river and having a water passage formed on its upper side for the flow of the river, a capture body fixed to the upstream surface which is the upstream side of the weir body, and a fixing part that fixes the capture body to the upstream surface, wherein the capture body includes a capture section that captures driftwood upstream of the weir body so that the driftwood does not pass through the water passage, a plurality of legs extending from the capture section toward the upstream surface, and a plate-shaped first plate-shaped member attached to the end of each of the plurality of legs opposite to the side of the capture section, and the fixing part corresponds to each of the plurality of legs The fixing structure includes a fixing structure provided therein, each of which includes a plate-shaped second plate-shaped member that is in surface contact with the side surface of the upstream surface of the first plate-shaped member; a plurality of first holding portions that penetrate the vicinity of each corner of the second plate-shaped member and are driven into the upstream surface, and hold the second plate-shaped member spaced apart from the upstream surface so that the second plate-shaped member is parallel to the upstream surface; a plurality of second holding portions that penetrate the first plate-shaped member and the second plate-shaped member and are driven into the upstream surface, and maintain surface contact between the first plate-shaped member and the second plate-shaped member; and a filling portion that fills the gap between the second plate-shaped member and the upstream surface.

[0008] (2): In the weir of (1), the first retaining portion includes a first anchor bolt driven into the upstream surface and extending in a direction perpendicular to the upstream surface and passing through the second plate-shaped member, a first nut screwed onto the first anchor bolt on the side of the upstream surface relative to the second plate-shaped member, and a second nut screwed onto the first anchor bolt on the side of the second plate-shaped member opposite to the side of the upstream surface, and the second retaining portion includes a second anchor bolt driven into the upstream surface and extending in a direction perpendicular to the upstream surface and passing through the first plate-shaped member and the second plate-shaped member, a third nut screwed onto the second anchor bolt on the side of the upstream surface relative to the second plate-shaped member, and a fourth nut screwed onto the second anchor bolt on the side of the first plate-shaped member opposite to the side of the upstream surface, and the second plate-shaped member is fixed by being sandwiched between the first nut and the second nut, and the first plate-shaped member and the second plate-shaped member may be fixed by being sandwiched between the third nut and the fourth nut.

[0009] (3): In the weir of (2), the diameters of the first through-hole formed in the second plate-shaped member through which the second anchor bolt passes and the diameters of the second through-hole formed in the first plate-shaped member through which the second anchor bolt passes are larger than the outer diameters of the third nut and the fourth nut, respectively, and the second retaining portion includes a plate-shaped third plate-shaped member that covers the opening on the upstream side of the first through-hole and a plate-shaped fourth plate-shaped member that covers the opening on the opposite side of the second through-hole from the upstream side, and the first plate-shaped member, the second plate-shaped member, the third plate-shaped member and the fourth plate-shaped member may be sandwiched and fixed by the third nut and the fourth nut.

[0010] (4): In any of the weirs described in (1) to (3), the plurality of first retaining parts may include four first retaining parts, the plurality of second retaining parts may include four second retaining parts, two of the four second retaining parts may be arranged on a first diagonal connecting two of the four first retaining parts, and the other two of the four second retaining parts may be arranged on a second diagonal connecting two of the four first retaining parts.

[0011] (5) In any of the weirs described in (1) to (4), the upstream surface of the weir body includes a first surface that slopes upward as it goes downward when viewed from a direction crossing the river, and a second surface connected to the upper end of the first surface and extending in the height direction of the weir body when viewed from a direction crossing the river, and the plurality of legs may include a plurality of first legs extending toward the first surface and a plurality of second legs extending toward the second surface.

[0012] (6): In the weir of (5), the plurality of first legs may include pairs of first legs that are arranged on a straight line extending in the height direction when viewed from the direction of the river flow.

[0013] (7): In the weir of (6), four to seven of the second retaining parts may be provided for each of the pair of first legs.

[0014] (8) In the weir of (6) or (7), the fixing structure corresponding to the lower of the pair of first legs may further include a support that supports the first leg from below.

[0015] (9): In any of the weirs described in (5) to (8), four to eight of the second retaining parts may be provided for each of the plurality of second legs.

[0016] (10): In any of the weirs described in (5) to (9), the fixing structure corresponding to the second leg may further include a support that supports the second leg from below.

[0017] (11): The weir construction method according to the present invention comprises a preparation step of preparing a structure including legs with plate-shaped first plate members attached to their ends; a first driving step of driving a first anchor bolt with a first nut attached perpendicular to the upstream surface, which is the upstream surface of the weir body that is arranged across the river and has a water passage section formed on the upper side for the flow of the river; a second driving step of driving a second anchor bolt with a third nut attached perpendicular to the upstream surface, which is the upstream surface; a first insertion step of inserting a plate-shaped second plate member onto the first and second anchor bolts after the first and second driving steps; a second insertion step of inserting a second nut onto the first anchor bolt after the first insertion step; and after the second insertion step, positioning the second plate member so that it is parallel to the upstream surface. The structure comprises: an arrangement step of positioning the second plate-shaped member at a position spaced apart from the upstream surface by sandwiching the second plate-shaped member between the first and second nuts while adjusting the positions of the first and second nuts on the first anchor bolt; a third insertion step of inserting the first plate-shaped member of the structure onto the second anchor bolt after the arrangement step to bring it into surface contact with the second plate-shaped member; a fourth insertion step of inserting the fourth nut onto the second anchor bolt after the third insertion step; a structure installation step of installing the structure on the dam body by tightening the third and fourth nuts to maintain surface contact between the first and second plate-shaped members; and a filling step of forming a filling portion in the gap between the second plate-shaped member and the upstream surface after the structure installation step.

[0018] (12) In the method for constructing the dam of (11), the hole diameters of the first through-hole through which the second anchor bolt formed in the second plate-shaped member penetrates and the second through-hole through which the second anchor bolt formed in the first plate-shaped member penetrates are each larger than the outer diameters of the third nut and the fourth nut. In the second placing step, a plate-shaped third plate-shaped member capable of covering the opening of the first through-hole is inserted through the second anchor bolt. In the fourth insertion step, before inserting the fourth nut through the second anchor bolt, a plate-shaped fourth plate-shaped member capable of covering the opening of the second through-hole is inserted through the second anchor bolt. In the structure installation step, the first plate-shaped member, the second plate-shaped member, the third plate-shaped member, and the fourth plate-shaped member may be sandwiched and fixed by the third nut and the fourth nut.

Advantages of the Invention

[0019] According to the present invention, there are provided a dam in which a gap is unlikely to occur at a fixing portion between a capturing body and a dam body, and a method for constructing the dam.

Brief Description of the Drawings

[0020] [Figure 1] It is a front view showing a dam according to an embodiment of the present invention (viewed from the upstream side in the flow direction of the river). [Figure 2] It is a side view showing a first structure unit of a capturing body in the dam shown in FIG. 1 together with the dam body (viewed from a direction crossing the river). [Figure 3] It is a side view showing a second structure unit of a capturing body in the dam shown in FIG. 1 together with the dam body. [Figure 4] It is a view of one of a plurality of fixing structures of a fixing portion in the dam shown in FIG. 1, viewed from a direction perpendicular to the upstream surface of the dam body (out-of-plane direction). [Figure 5] It is a view of the fixing structure shown in FIG. 四, viewed from the in-plane direction of the upstream surface of the dam body, and is a view showing the inside of the filling portion in a perspective manner. [Figure 6]It is a flowchart for explaining a levee construction method for constructing a levee according to an embodiment of the present invention. [Figure 7] It is a plan view (viewed from the out-of-plane direction) showing the second plate-like member. [Figure 8] It is a diagram showing the state of the placing process. [Figure 9] It is a side view showing the state of the levee main body after the placing process. [Figure 10] It is a front view showing the state of the levee main body after the placing process. [Figure 11] It is a diagram showing the state of the first insertion process. [Figure 12] It is a side view showing the state of the levee main body after the first insertion process. [Figure 13] It is a front view showing the state of the levee main body after the first insertion process. [Figure 14] It is a diagram showing the state of the second insertion process and the arrangement process. [Figure 15] It is a diagram showing the state of the third insertion process, the fourth insertion process, and the structure installation process. [Figure 16] It is a front view showing the state where the first structure is installed by the structure installation process. [Figure 17] It is a side view showing the state where the second structure (second part) is installed by the structure installation process.

Embodiments for Carrying Out the Invention

[0021] Hereinafter, embodiments for implementing a levee according to the present invention and a levee construction method for constructing the levee are illustrated together with the accompanying drawings. The embodiments illustrated below are for facilitating the understanding of the present invention and are not for limiting the interpretation of the present invention. The present invention can be changed and improved from the following embodiments without departing from the gist thereof. Also, in the above accompanying drawings, the dimensions of each member may be exaggerated or reduced for easy understanding, or hatching may be omitted.

[0022] Figure 1 is a front view (viewed from the upstream side in the direction of river flow) of a weir according to an embodiment of the present invention. As shown in Figure 1, the river on which the weir 1 is installed has a riverbed RB (ground). The direction of the river flow on which the weir 1 is installed is from the front side of the paper to the back side of the paper, and the weir 1 is positioned along the direction that crosses the river. Hereinafter, the direction of river flow will be referred to as "flow direction FL", and the direction that crosses the river (the direction in which the weir 1 extends) will be referred to as "crossing direction A".

[0023] Dam 1 comprises a dam body 2, a trapping body 3, and a fixing part 4.

[0024] The weir body 2 is constructed so that its bottom is embedded in the riverbed RB and it extends along the transverse direction A. The weir body 2 may be constructed of concrete or soil cement, for example. The weir body 2 has an upstream face 23, which is the face on the upstream side in the flow direction FL. In addition, the wall surface of the weir body 2 facing the upstream or downstream side of the river may be a steel plate wall formed by connecting a plurality of steel segments, and the interior may be filled with concrete or soil cement.

[0025] The trapping body 3 is provided on the upstream face 23 of the dam body 2. Specifically, the trapping body 3 is fixed to the upstream face 23 by a fixing part 4. In the transverse direction A, the trapping body 3 includes a first structural unit 31 located on the furthest and furthest sides of the trapping body 3, and second structural units 32 other than the first structural units 31. The two first structural units 31 and the multiple second structural units 32 are arranged in line in the transverse direction A.

[0026] Figure 2 is a side view (viewed from the cross-sectional direction A) showing the first structural unit 31 together with the dam body 2. Figure 3 is a side view (viewed from the cross-sectional direction A) showing the second structural unit 32 together with the dam body 2.

[0027] As shown in Figures 1 to 3, the dam body 2 includes a base section 21 and a pair of sleeve sections 22, 22. The base section 21 has its bottom embedded in the riverbed RB and is constructed to extend along the transverse direction A. When viewed from the transverse direction A, the base section 21 is formed in a trapezoidal shape that becomes narrower towards the upper part in the vertical direction (hereinafter sometimes simply referred to as "upper"). In this embodiment, the vertical direction is the height direction of the weir 1. The riverbed RB side in the vertical direction (height direction) may be referred to as "down". The base portion 21 includes the upstream side surface (hereinafter referred to as "first surface 231"). The first surface 231, when viewed from the transverse direction A, is inclined to protrude upstream in the flow direction FL as it goes downwards.

[0028] Each of the pair of sleeve portions 22, 22 is connected to the upper end (upper end surface 21A) of the base portion 21. More specifically, in the transverse direction A, one sleeve portion 22 is connected to one side of the upper end surface 21A, and the other sleeve portion 22 is connected to the other side of the upper end surface 21A. That is, the pair of sleeve portions 22 are spaced apart in the transverse direction A. In the transverse direction A, each sleeve portion 22 includes a side surface 22A that faces the other sleeve portion 22. The side surface 22A is inclined so as it extends downwards toward the other side surface 22A when viewed from the flow direction FL. Also, each of the pair of sleeve portions 22, 22 is formed in a rectangular (or square) shape when viewed from the transverse direction A. Therefore, each of the pair of sleeve portions 22, 22 includes an upstream surface (hereinafter referred to as "second surface 232") that extends in the vertical direction (height direction). The second surface 232 is connected to the upper end of the first surface 231. Therefore, the upstream surface 23 of the dam body 2 includes the first surface 231 and the second surface 232.

[0029] As shown in Figure 1, a recess 24 is formed on the central side of the weir body 2 in the transverse direction A. This recess 24 is an open space formed by the respective side surfaces 22A of a pair of sleeve portions 22, 22 and the upper end surface 21A of the base portion 21. River water can pass through this recess 24 and flow downstream. In other words, the recess 24 functions as a water passage section of the weir 1. Hereafter, the recess 24 will be referred to as the "water passage section 24". Therefore, the weir body 2 has a water passage section 24 formed on its upper side that allows river water to pass through.

[0030] As shown in Figures 1 to 3, the trapping body 3 is fixed to the upstream surface 23 so as to cross the water passage section 24 along the transverse direction A. Therefore, driftwood flowing on the river surface is captured by the trapping body 3, thereby preventing the driftwood from flowing downstream of the weir 1.

[0031] As shown in Figures 1 and 2, the first structural unit 31 of the capture body 3 includes a first structure 301 (structure) and a second structure 302 (structure).

[0032] The first structure 301 has a lambda-shaped form when viewed from the transverse direction A. Specifically, the first structure 301 includes a vertical member 3013 and a pair of legs 3011, 3011. Hereinafter, the legs 3011 will be referred to as "first leg 3011". A flange F is attached to the upper end of the vertical member 3013. The pair of first legs 3011, 3011 are aligned on a straight line extending vertically (height direction) when viewed from the flow direction FL. The lower of the pair of first legs 3011, 3011, the first leg 3011A, is connected to the lower end of the vertical member 3013 and extends toward the first surface 231 of the dam body 2. The first leg 3011A is inclined with respect to the direction perpendicular to the first surface 231. Specifically, the first leg portion 3011A extends diagonally upward from its lower end. The lower end of the vertical member 3103 is connected to the upper end of the first leg portion 3011A. The upper of the pair of first leg portions 3011, 3011, the first leg portion 3011B, is connected near the upper end of the first leg portion 3011A and extends toward the first surface 231. Specifically, the first leg portion 3011B extends diagonally upward from its lower end. The angle of inclination of the first leg portion 3011B with respect to the direction perpendicular to the first surface 231 is smaller than the angle of inclination of the first leg portion 3011A with respect to the direction perpendicular to the first surface 231.

[0033] The lower ends of each of the pair of first leg portions 3011, 3011 (the side of the capture portion 304 described later) A plate-shaped member (hereinafter referred to as "first plate-shaped member BM1") is attached to the opposite end. The first plate-shaped member BM1 may be, for example, a metal plate, or more specifically, a steel plate. The planar shape (shape viewed from the out-of-plane direction) of the first plate-shaped member BM1 is not particularly limited, but in this embodiment it is circular. As will be explained again later, the first structure 301 is fixed to the upstream surface 23 of the dam body 2 by fixing the first plate-shaped member BM1 attached to the first leg portion 3011 to the first surface 231 by the fixing structure 41 (fixing structure 41A, 41B) of the fixing portion 4. The first plate-shaped member BM1 attached to the first leg portion 3011 is attached to a pair of first leg portions 3011, 3011 so as to be parallel to the first surface 231 when the first structure 301 is fixed to the first surface 231. In other words, the first plate-shaped member BM1 is attached to the first leg portion 3011 so as to be parallel to the upstream surface 23 when the capture body 3 is fixed to the dam body 2.

[0034] The second structure 302 includes a first part 302A located on the side farther from the main dam body 2, and a second part 302B located on the side closer to the main dam body 2. Note that the second part 302B alone may sometimes be referred to as the second structure (structure).

[0035] The first part 302A includes a vertical member 3021 extending vertically (in the height direction), a horizontal member 3025 extending from the vertical member 3021 to one side (or the other side) in the transverse direction A, and a leg portion 3022 extending from the vertical member 3021 toward the second surface 232 along a direction perpendicular to the second surface 232 (i.e., the flow direction FL). A flange F is attached to the end of the leg portion 3022 on the side facing the second surface 232. In the vertical direction (in the height direction), the horizontal member 3025 and the leg portion 3022 are in approximately the same position. A flange F is attached to the lower end of the vertical member 3021. The flange F of the vertical member 3021 and the flange F attached to the vertical member 3013 of the first structure 301 are joined in surface contact.

[0036] The second part 302B includes a leg portion 3023 extending toward the second surface 232 along a direction perpendicular to the second surface 232 (i.e., the flow direction FL), and one or more longitudinal members 3024 extending in the vertical direction (height direction). Hereinafter, the leg portion 3023 will be referred to as the "second leg portion 3023". A flange F is attached to the end of the second leg portion 3023 opposite to the second surface 232 side (i.e., the upstream side). The flange F attached to the second leg portion 3023 and the flange F attached to the leg portion 3022 of the first part 302A are joined in surface contact.

[0037] A first plate-shaped member BM1 is attached to the end of the second leg portion 3023 on the side of the second surface 232 (i.e., the downstream side or the side opposite to the capture portion 304, which will be described later). As will be explained again later, the second portion 302B is fixed to the upstream surface 23 of the dam body 2 by the fixing structure 41 (fixing structure 41C) of the fixing portion 4, which fixes the first plate-shaped member BM1 attached to the second leg portion 3023 to the second surface 232. The first plate-shaped member BM1 is attached to the second leg portion 3023 so as to be parallel to the second surface 232 when the second portion 302B (second structure) is fixed to the second surface 232. In other words, the first plate-shaped member BM1 is attached to the second leg portion 3023 so as to be parallel to the upstream surface 23 when the capture body 3 is fixed to the dam body 2.

[0038] As shown in Figures 1 and 3, the second structural unit 32 includes the first structural unit 301 (structure) and the third structural unit 303. The third structural unit 303 has a cross shape when viewed from the flow direction FL. That is, the third structural unit 303 includes a vertical member 3031 extending in the vertical direction (height direction) and horizontal members 3032 extending from the vertical member 3031 on both sides in the transverse direction A. A flange F is attached to the lower end of the vertical member 3031. The flange F attached to the vertical member 3031 and the flange F attached to the vertical member 3013 of the first structural unit 301 are joined in a state of surface contact. Flanges are attached to both ends of the horizontal member 3032. A flange F is attached. The flange F attached to the cross member 3032 and the flange F attached to the cross member 3025 of the first part 302A of the second structure 302, or the flange F attached to any other cross member 3032 adjacent to the cross member 3032, are joined in a surface contact state.

[0039] The trapping body 3 is constructed by arranging and joining two first structural units 31 and a plurality of second structural units 32 in the transverse direction A. This configuration allows the trapping body 3 to include a trapping section 304, a plurality of legs extending from the trapping section 304 toward the upstream surface 23, and a first plate-like member BM1 attached to each of the plurality of legs. Specifically, the trapping section 304 may include a plurality of third structural units 303, vertical members 3013 of a plurality of first structural units 301, and first parts 302A of two second structural units 302. Furthermore, the plurality of legs may include a pair of first legs 3011, 3011 of a plurality of first structural units 301 and second legs 3023 of two second structural units 302.

[0040] The capture section 304 is positioned at a distance upstream from the upstream surface 23 by multiple legs, including multiple first legs 3011 and multiple second legs 3023, and faces the water passage section 24. Therefore, driftwood flowing downstream on the river surface is captured by the capture section 304 by multiple vertical members 3031 and multiple horizontal members 3032 aligned in a straight line along the transverse direction A. In this way, the capture section 304 captures driftwood flowing in the river upstream of the weir body 2 so that it does not pass through the water passage section 24. Furthermore, driftwood that has gone around to the outside (bank side) of both sides in the transverse direction A of the capture section 304 is also blocked by the legs 3022, 3023 and vertical members 3024 of the second structure 302. As a result, the weir 1 prevents driftwood from reaching the water passage section 24.

[0041] The capture body 3 described above is fixed to the dam body 2 by the first plate-shaped member BM1, which is attached to the ends of the first leg portion 3011 and the second leg portion 3023 opposite to the capture portion 304 side (i.e., the downstream side), being fixed to the upstream surface 23 by the fixing structure 41 of the fixing portion 4.

[0042] Next, the fixing part 4 and the fixing structure 41 will be described.

[0043] As shown in Figure 1, the fixing section 4 includes a plurality of fixing structures 41. The plurality of fixing structures 41 are provided corresponding to a plurality of legs. That is, the plurality of fixing structures 41 are provided in a one-to-one correspondence with a plurality of first legs 3011 (a plurality of first legs 3011A and a plurality of first legs 3011B) and two second legs 3023. As shown in Figures 1 to 3, the first leg 3011A is fixed to the first surface 231 of the upstream surface 23 by fixing structure 41A, the first leg 3011B is fixed to the first surface 231 of the upstream surface 23 by fixing structure 41B, and the second leg 3023 is fixed to the second surface 232 of the upstream surface 23 by fixing structure 41C. Fixing structures 41A and 41C have the same configuration, and fixing structure 41B differs from fixing structures 41A and 41C only in that it does not include the support section 415 which will be described later.

[0044] Figure 4 shows any one of the multiple fixing structures 41A and multiple fixing structures 41C as seen from a direction perpendicular to the upstream surface 23 (out-of-plane direction of the upstream surface 23). Figure 5 shows the fixing structure 41 shown in Figure 4 as seen from the in-plane direction of the upstream surface 23 (first surface 231), and is a transparent view of the inside of the filling portion 413, which will be described later.

[0045] As shown in Figures 4 and 5, the fixing structure 41 includes a plate-shaped member (hereinafter referred to as "second plate-shaped member BM2"), a plurality of first holding parts 411, a plurality of second holding parts 412, a filling part 413, and a support part 415. As mentioned above, the fixing structure 41B does not have a support part 415.

[0046] The second plate-like member BM2 may be, for example, a metal plate, more specifically, a steel plate. The planar shape (shape viewed from the out-of-plane direction) of the second plate-like member BM2 is not particularly limited, as long as its outer shape is larger than the planar shape of the first plate-like member BM1. In this embodiment, the planar shape of the second plate-like member BM2 is rectangular, but it may be, for example, a square or other quadrilateral, a triangle, a polygon with pentagons or more, a circle, or an oval. The second plate-like member BM2 is in surface contact with the surface of the first plate-like member BM1 on the side of the upstream surface 23.

[0047] In this embodiment, four holes Ha are formed in the vicinity of each of the four corners of the second plate-shaped member BM2, penetrating the second plate-shaped member BM2. In other words, the second plate-shaped member BM2 has four holes Ha. A first retaining portion 411 is placed in each of these holes Ha. That is, in this embodiment, the number of first retaining portions 411 is four. Here, "corners of the second plate-shaped member BM2" refers not only to the four corners of the second plate-shaped member BM2 when the second plate-shaped member BM2 is quadrilateral, but also to the four corners of a quadrilateral inscribed in the outer shape of the second plate-shaped member BM2 when the second plate-shaped member BM2 is elliptical, circular, or a polygon with five or more sides. Furthermore, "near the corners" may refer to the area inside a quarter circle Cr centered on a corner of the second plate-shaped member BM2, with a radius of, for example, 1 / 4 of the length of one of the two sides forming the corner. In Figure 4, the quarter circle Cr is shown as a dashed line for illustrative purposes. Furthermore, in Figure 4, the specific configuration of the first retaining portion 411 located in the hole Ha is omitted in order to show the hole Ha.

[0048] If the second plate-like member BM2 is, for example, triangular, the first holding portion 411 may be provided near each of the three corners, or if the second plate-like member BM2 is a polygon with five or more sides, the first holding portion 411 may be provided near each of the corners of the polygon.

[0049] Multiple through holes (hereinafter referred to as "first through holes Hb") are formed in the inner portion of the second plate-shaped member BM2. A second retaining portion 412 is positioned in each of these first through holes Hb. The position of the first through holes Hb is not particularly limited, but in this embodiment, two first through holes Hb are formed on the diagonal line connecting two of the four first retaining portions 411 (first diagonal line Di1), and two first through holes Hb are formed on the diagonal line connecting the other two first retaining portions 411 (second diagonal line Di2). In other words, in this embodiment, four first through holes Hb are formed. For convenience, in Figure 4, the first diagonal line Di1 and the second diagonal line Di2 are shown as dashed lines.

[0050] As shown in Figure 5, the first plate-shaped member BM1 attached to the first leg portion 3011 and the second leg portion 3023 of the capture body 3 has a plurality of through holes (hereinafter referred to as "second through holes Hc") that penetrate the first plate-shaped member BM1. Also, as shown in Figures 4 and 5, in the capture body 3, the lower ends of the first leg portion 3011 and the second leg portion 3023 are provided with a plurality of ribs Ri that are joined to the outer circumferential surface of the leg portion 3011 and 3023 and to the surface of the first plate-shaped member BM1 opposite to the upstream surface 23. These ribs Ri strengthen the joint strength between the leg portions 3011 and 3023 and the first plate-shaped member BM1.

[0051] As shown in Figure 4, in this embodiment, eight ribs Ri are provided at approximately equal intervals in the circumferential direction of the leg portions 3011 and 3023. Therefore, when the first plate-shaped member BM1 is viewed from the out-of-plane direction, eight sections DA are formed on the first plate-shaped member BM1, defined by the outer circumferential surfaces of the leg portions 3011 and 3023 and the two ribs Ri, Ri. In this embodiment, one second through hole Hc is formed in each of the two sections DA, DA on the first diagonal Di1, and each of the two sections DA, DA on the second diagonal Di2 In this embodiment, one second through-hole Hc is formed in the first plate-like member BM1.

[0052] As shown in Figures 4 and 5, in the dam 1, the first through-hole Hb of the second plate-shaped member BM2 communicates with the second through-hole Hc of the first plate-shaped member BM1. Hereinafter, the communicating first through-hole Hb and second through-hole Hc may be referred to as "communication holes Hb,Hc". In this embodiment, the first plate-shaped member BM1 and the second plate-shaped member BM2 have four communication holes Hb,Hc formed therein. Two of the four communication holes Hb,Hc are on the first diagonal line Di1 described above, and the other two communication holes Hb,Hc are on the second diagonal line Di2 described above. In addition, in this embodiment, the hole diameters of the first through-hole Hb and the second through-hole Hc are the same. That is, in this embodiment, the communication holes Hb,Hc have a hole diameter Da.

[0053] As shown in Figures 4 and 5, the first retaining portions 411 are positioned in each of the four holes Ha formed in the second plate-shaped member BM2. Therefore, the four first retaining portions 411 are provided near each of the four corners of the second plate-shaped member BM2. The four first retaining portions 411 are driven into the upstream surface 23, penetrating near each of the four corners of the second plate-shaped member BM2, and hold the second plate-shaped member BM2 spaced apart from the upstream surface 23 so that the second plate-shaped member BM2 is parallel to the upstream surface 23. An example of the configuration of the first retaining portions 411 will be described below.

[0054] As shown in Figure 5, in this embodiment, the first retaining portion 411 includes a first anchor bolt 4111, a first nut 4112, and a second nut 4113.

[0055] The first anchor bolt 4111 is driven into the upstream surface 23 and extends in a direction perpendicular to the upstream surface 23 (out-of-plane direction), passing through the hole Ha of the second plate-shaped member BM2. Note that "perpendicular to the upstream surface 23" may include cases where it is not perpendicular to the upstream surface 23 due to manufacturing errors, tolerances, and installation errors. The outer diameter of the first anchor bolt 4111 may be substantially the same as the diameter of the hole Ha (slightly smaller than the diameter of the hole Ha). As shown in Figures 2 and 3, the first anchor bolt 4111 provided for the first leg portion 3011 extends in a direction perpendicular to the first surface 231, and the first anchor bolt 4111 provided for the second leg portion 3023 extends in a direction perpendicular to the second surface 232 (i.e., the flow direction FL).

[0056] Returning to Figure 5, the first nut 4112 is screwed onto the first anchor bolt 4111 on the side of the upstream surface 23 relative to the second plate-like member BM2. The outer shape (e.g., outer diameter) of the first nut 4112 is larger than the hole diameter of hole Ha. The second nut 4113 is screwed onto the first anchor bolt 4111 on the side of the second plate-like member BM2 opposite to the side of the upstream surface 23 relative to the second plate-like member BM2. The outer shape (e.g., outer diameter) of the second nut 4113 is larger than the hole diameter of hole Ha.

[0057] In the fixing structure 41, each of the first retaining parts 411 positioned near each of the four corners of the second plate-shaped member BM2 secures the second plate-shaped member BM2 by sandwiching it between a first nut 4112 and a second nut 4113. By adjusting the positions of the first nut 4112 and the second nut 4113 in the direction perpendicular to the upstream surface 23 at each of the first retaining parts 411 positioned near each of the four corners of the second plate-shaped member BM2, the second plate-shaped member BM2 is held parallel to the upstream surface 23 while being spaced apart from it.

[0058] As shown in Figures 4 and 5, the second retaining portion 412 is positioned in each of the four communication holes Hb and Hc formed in the first plate-shaped member BM1 and the second plate-shaped member BM2. Therefore, in this embodiment, there are four second retaining portions 412, of which two second retaining portions 412, 412 are positioned on the first diagonal Di1 described above, and the other two second retaining portions 412, 412 are positioned on the second diagonal Di2 described above. Each of the (multiple) second retaining portions 412 is cast into the upstream surface 23, passing through each of the four communication holes Hb,Hc (i.e., passing through the first plate-shaped member BM1 and the second plate-shaped member BM2), and maintains surface contact between the first plate-shaped member BM1 and the second plate-shaped member BM2. An example of the configuration of the four (multiple) second retaining portions 412 will be described below.

[0059] The second retaining portion 412 includes a second anchor bolt 4121, a third nut 4122, a fourth nut 4123, a third plate-shaped member BM3, a fourth plate-shaped member BM4, and a fifth plate-shaped member BM5.

[0060] The second anchor bolt 4121 is driven into the upstream surface 23 and extends in a direction perpendicular to the upstream surface 23 (out-of-plane direction), passing through the communication holes Hb and Hc (i.e., passing through the first plate-shaped member BM1 and the second plate-shaped member BM2). As shown in Figures 2 and 3, the second anchor bolt 4121 provided for the first leg portion 3011 extends in a direction perpendicular to the first surface 231, and the second anchor bolt 4121 provided for the second leg portion 3023 extends in a direction perpendicular to the second surface 232 (i.e., the flow direction FL).

[0061] Returning to Figure 5, the third nut 4122 is screwed onto the second anchor bolt 4121 on the upstream side 23 relative to the second plate-shaped member BM2. In this embodiment, the outer shape (e.g., outer diameter Db) of the third nut 4122 is smaller than the hole diameter Da of the communication holes Hb,Hc. The fourth nut 4123 is screwed onto the second anchor bolt 4121 on the side opposite to the upstream side 23 relative to the second plate-shaped member BM2. In this embodiment, the outer shape (e.g., outer diameter Dc) of the fourth nut 4123 is smaller than the hole diameter Da of the communication holes Hb,Hc.

[0062] In Figure 5, the fourth nut 4123 is shown as a double nut, but it may also be a single nut. However, since the side opposite to the upstream surface 23 relative to the second plate-shaped member BM2 is open to the external space, space is secured for placing a double nut. For this reason, for example, from the viewpoint of suppressing nut loosening, it may be preferable to make the fourth nut 4123 a double nut.

[0063] As shown in Figure 5, the third plate-shaped member BM3 is a plate-shaped member (for example, a metal plate) having an outer diameter larger than the hole diameter Da of the communication holes Hb and Hc. The third plate-shaped member BM3 is inserted through the second anchor bolt 4121 and covers the opening on the upstream side 23 of the communication holes Hb and Hc (i.e., the opening on the upstream side 23 of the first through hole Hb). The third plate-shaped member BM3 is positioned between the second plate-shaped member BM2 and the third nut 4122 and is sandwiched between the second plate-shaped member BM2 and the third nut 4122. That is, the third nut 4122 is in contact with the surface of the third plate-shaped member BM3 on the upstream side 23.

[0064] The fourth plate-shaped member BM4 is a plate-shaped member (for example, a metal plate) having an outer diameter larger than the hole diameter Da of the communication holes Hb and Hc. The fourth plate-shaped member BM4 is inserted through the second anchor bolt 4121 and covers the opening of the communication holes Hb and Hc on the side opposite to the upstream surface 23 (i.e., the opening of the second through hole Hc on the side opposite to the upstream surface 23). The fourth plate-shaped member BM4 is in contact with the side of the first plate-shaped member BM1 opposite to the upstream surface 23. The fifth plate-shaped member BM5 may be, for example, a washer. The fifth plate-shaped member BM5 is inserted through the second anchor bolt 4121 and is positioned between the fourth plate-shaped member BM4 and the fourth nut 4123. Therefore, the fourth plate-shaped member BM4 and the fifth plate-shaped member BM5 are sandwiched between the first plate-shaped member BM1 and the fourth nut 4123. In this embodiment, providing the fifth plate-shaped member BM5 is optional.

[0065] The thickness of the third plate-shaped member BM3 and the fourth plate-shaped member BM4 is, for example, the thickness of the first structure 301, the second structure 302, the first structural unit 31, and the second structural unit 32. The plate thickness may be sufficient to withstand the pressure from the third nut 4122 and the fourth nut 4123 caused by one or more loads pulling the second anchor bolt 4121 toward the opposite side of the upstream surface 23 or pushing toward the upstream surface 23 in the out-of-plane direction of the upstream surface 23. For example, the plate thickness of the third plate member BM3 and the fourth plate member BM4 may be about 12 mm if the second anchor bolt 4121 is, for example, an M24 bolt equivalent to SS400.

[0066] In this embodiment, the first plate-shaped member BM1 and the second plate-shaped member BM2 are held in a state of surface contact by the third nuts 4122 and fourth nuts 4123 of each of the four (or more) second holding parts 412, which sandwich and fix the first plate-shaped member BM1, the second plate-shaped member BM2, the third plate-shaped member BM3, the fourth plate-shaped member BM4, and the fifth plate-shaped member BM5.

[0067] As shown in Figure 5, the filling portion 413 of the fixed structure 41 fills the gap Ga between the second plate-shaped member BM2, which is held by four first holding portions 411 spaced apart from the upstream surface 23 and parallel to the upstream surface 23, and the upstream surface 23. The material forming the filling portion 413 is preferably a material that is fluid during construction, solidifies after construction, and has low shrinkage after solidification. For example, it may be a non-shrink mortar.

[0068] As shown in Figures 4 and 5, the support portions 415 of the fixing structure 41A and the fixing structure 41C are attached to the second plate-shaped member BM2. Specifically, the support portions 415 are attached to the vertically lower region of the second plate-shaped member BM2 when the second plate-shaped member BM2 is held spaced apart from the upstream surface 23 by the first holding portion 411. The support portion 415 includes a main body portion 4151 and one or more fixing portions 4152. In this embodiment, the main body portion 4151 may be angle steel and includes a first portion 4151A extending in the in-plane direction of the second plate-shaped member BM2 and a second portion 4151B extending out-of-plane direction of the second plate-shaped member BM2 (i.e., perpendicular to the first portion 4151A). The main body portion 4151 is fixed to the second plate-shaped member BM2 such that when the second plate-shaped member BM2 is held by the first holding portion 411 spaced apart from the upstream surface 23, the second portion 4151B is located at the upper vertical end of the main body portion 4151. The first portion 4151A has an elongated hole 4151AH that extends vertically (height direction) when viewed from the flow direction FL when the second plate-shaped member BM2 is held by the first holding portion 411 spaced apart from the upstream surface 23. In this embodiment, two elongated holes 4151AH are formed. Specifically, one elongated hole 4151AH is formed near each of the ends in the transverse direction A of the first portion 4151A.

[0069] The second plate-shaped member BM2 has a through hole Hd that communicates with the elongated hole 4151AH, corresponding to the elongated hole 4151AH. In this embodiment, two through holes Hd are formed corresponding to the two elongated holes 4151AH. In this embodiment, each of the one or more fixing parts 4152 includes a bolt 4152A and a pair of nuts 4152B and 4152C. The number of fixing parts 4152 is the same as the number of elongated holes 4152AH, which is two in this embodiment. The bolt 4152A of the fixing part 4152 passes through the through hole Hd and the elongated hole 4151AH. The nut 4152B is inserted onto the bolt 4152A from the side of the upstream surface 23, and the nut 4152C is inserted onto the bolt 4152A from the side opposite to the upstream surface 23. The support portion 415 is fixed to the second plate-shaped member BM2 by a pair of nuts 4152B and 4152C that sandwich and fix the second plate-shaped member BM2 and the first portion 4151A of the main body portion 4151. Specifically, the support portion 415 is fixed to the second plate-shaped member BM2 such that the second portion 4151B of the main body portion 4151 contacts the lower end of the first plate-shaped member BM1, which is held in surface contact with the second plate-shaped member BM2.

[0070] Furthermore, when attaching the support portion 415 to the second plate-shaped member BM2, the position through which the bolt 4152A passes in the elongated hole 4151AH can be appropriately adjusted, thereby allowing the second main body portion 4151 to be attached to the second plate-shaped member BM2. The support portion 415 can be fixed to the second plate-shaped member BM2 such that portion 4151B contacts the lower end of the first plate-shaped member BM1.

[0071] As described above, the weir 1 comprises a weir body 2 positioned across the river and having a water passage section 24 formed on its upper side to allow the river flow to pass through, a capture body 3 fixed to the upstream face 23 of the weir body 2, and a fixing part 4 that fixes the capture body 3 to the upstream face 23. The capture body 3 includes a capture section 304 that captures driftwood upstream of the weir body 2 to prevent it from passing through the water passage section 24, a plurality of legs (a plurality of first legs 3011 and a plurality of second legs 3023) extending from the capture section 304 toward the upstream face 23, and a plate-shaped first plate-shaped member BM1 attached to the end of each of the plurality of legs opposite to the side of the capture section 304. The fixing portion 4 includes a fixing structure 41 provided corresponding to each of the multiple leg portions, and each fixing structure 41 includes a plate-shaped second plate-shaped member BM2 that is in surface contact with the side surface of the upstream surface 23 of the first plate-shaped member BM1, a plurality of first holding portions 411 that are driven into the upstream surface 23 by penetrating the vicinity of each corner of the second plate-shaped member BM2 and holding the second plate-shaped member BM2 spaced apart from the upstream surface 23 so that the second plate-shaped member BM2 is parallel to the upstream surface 23, a plurality of second holding portions 412 that are driven into the upstream surface 23 by penetrating the first plate-shaped member BM1 and the second plate-shaped member BM2 and maintaining surface contact between the first plate-shaped member BM1 and the second plate-shaped member BM2, and a filling portion 413 that is filled in the gap Ga between the second plate-shaped member BM2 and the upstream surface 23.

[0072] As described above, in the weir 1, the first plate-shaped member BM1 is attached to the first leg portion 3011 and the second leg portion 3023 so as to be parallel to the upstream surface 23 when the capture body 3 is fixed to the weir body 2, and the second plate-shaped member BM2 is fixed parallel to the upstream surface 23 by the first holding portion 411, so that the first plate-shaped member BM1 and the second plate-shaped member BM2 are held in surface contact by the second holding portion 412, thereby suppressing the occurrence of a gap at the fixing point between the capture body 3 and the weir body 2 (i.e., the point where the first plate-shaped member BM1 and the second plate-shaped member BM2 are in contact).

[0073] Furthermore, in the weir 1, a first holding part 411 that holds the second plate-shaped member BM2, which serves as the base for attaching the capture body 3, to the weir body 2, and a second holding part 412 that maintains surface contact between the second plate-shaped member BM2 and the first plate-shaped member BM1 are provided separately. As a result, the process of attaching the second plate-shaped member BM2 parallel to the upstream surface 23 with the first holding part 411 and the process of maintaining surface contact between the first plate-shaped member BM1 and the second plate-shaped member BM2 with the second holding part 412 can be performed independently, making it possible to improve the accuracy of each process. Therefore, in the weir 1, the occurrence of gaps at the fixing points between the capture body 3 and the weir body 2 is further suppressed.

[0074] Furthermore, in the case of the weir 1, a filling portion 413 is provided in the gap Ga between the second plate-shaped member BM2 and the upstream surface 23, thereby strengthening the fixing strength of the fixing point between the capture body 3 and the weir body 2, and preventing the capture body 3 fixed to the weir body 2 from tilting due to its own weight.

[0075] Furthermore, according to the weir 1, the diameter Da of the first through-hole Hb formed in the second plate-shaped member BM2 through which the second anchor bolt 4121 passes, and the diameter Da of the second through-hole Hc formed in the first plate-shaped member BM1 through which the second anchor bolt 4121 passes, are larger than the outer diameter Db of the third nut 4122 and the outer diameter Dc of the fourth nut 4123. Thus, in this embodiment, because the diameter Da of the through-holes Hb and Hc is large, a certain amount of clearance (play) is secured between the inner surfaces of the second plate-shaped member BM2 and the first plate-shaped member BM1 that form the through-holes Hb and Hc, and the second anchor bolt 4121 that passes through the through-holes Hb and Hc. Therefore, even if there are manufacturing errors and tolerances when forming the through holes Hb and Hc, joining errors to the legs 3011 and 3023 of the first plate-shaped member BM1, or installation errors of the first plate-shaped member BM1 relative to the second plate-shaped member BM2, the first plate-shaped member BM1 and the second plate-shaped member will not be affected by these errors and tolerances. The position of the first plate-shaped member BM1 relative to the second plate-shaped member BM2 can be adjusted by the amount of play described above so that no gap is created between it and BM2. Therefore, in this embodiment, it is easier to make the first plate-shaped member BM1 into surface contact with the second plate-shaped member BM2 without any gaps, and as a result, the occurrence of gaps at the fixing points between the capture body 3 and the dam body 2 in the dam 1 is further suppressed.

[0076] Furthermore, according to this embodiment, the second retaining portion 412 includes a third plate-shaped member BM3 that covers the opening on the upstream surface 23 side of the first through hole Hb, and a fourth plate-shaped member BM4 that covers the opening on the opposite side of the second through hole Hc from the upstream surface 23 side. As a result, the third nut 4122 and the fourth nut 4123 are prevented from entering the through holes Hb and Hc, and the third nut 4122 and the fourth nut 4123 can maintain surface contact between the first plate-shaped member BM1 and the second plate-shaped member BM2 (via the third plate-shaped member BM3 and the fourth plate-shaped member BM4).

[0077] Furthermore, according to this embodiment, the fixing structure 41A positioned on the lower first leg portion 3011A of the pair of first leg portions 3011, 3011 includes a support portion 415 which includes a second portion 4151B that contacts the lower end of the first plate-shaped member BM1. As a result, the downward displacement of the first structure 301 is suppressed by the second portion 4151B. Similarly, the fixing structure 41C positioned on the second leg portion 3023 includes a support portion 415. As a result, the downward displacement of the second structure 302 is suppressed by the second portion 4151B. Thus, according to this embodiment, since the first leg portion 3011 and the second leg portion 3023 are supported from below by the support portion 415, tilting of the capture body 3 relative to the dam body 2 is suppressed, and as a result, the occurrence of gaps at the fixing points between the capture body 3 and the dam body 2 is further suppressed.

[0078] Next, we will explain the method for constructing Dam 1.

[0079] Figure 6 is a flowchart illustrating the dam construction method according to this embodiment. As shown in Figure 6, the dam construction method comprises a preparation step St1, a casting step St2, a first insertion step St3, a second insertion step St4, a placement step St5, a third insertion step St6, a fourth insertion step St7, a structure installation step St8, and a filling step St9.

[0080] (Preparation process St1) In preparation step St1, a structure including a leg portion to which a first plate-shaped member BM1 is attached at the end is prepared. The structure prepared in preparation step St1 includes a first structure 301 and a second structure 302 including a first part 302A and a second part 302B, or a second structure 302 consisting only of the second part 302B.

[0081] In addition, a second plate-shaped member BM2 may be prepared in preparation step St1. As shown in Figure 7, the second plate-shaped member BM2 is formed in a rectangular shape when viewed from the out-of-plane direction, and holes Ha are formed near each of the four corners of the second plate-shaped member BM2. Two first through holes Hb are formed on the first diagonal Di1 connecting two holes Ha of the second plate-shaped member BM2, and two first through holes Hb are formed on the second diagonal Di2 connecting the other two holes Ha. Furthermore, support parts 415 are attached to some of the second plate-shaped members BM2 prepared in preparation step St1. For convenience, in Figure 7, the first diagonal Di1 and the second diagonal Di2 are shown as dashed lines.

[0082] (Concrete pouring process St2) Next, the casting process St2 is performed. As shown in Figure 6, the casting process St2 includes the first casting process St21 and the second casting process St22. Figure 8 shows the casting process St2. As shown in Figure 8, the first casting process St21 involves driving the first anchor bolt 4111, to which the first nut 4112 is attached, perpendicular to the upstream face 23 of the dam body 2 into the upstream face 23. The first anchor bolt 4111 is installed on the upstream surface 23, and there is a gap between the first nut 4112 and the upstream surface 23.

[0083] Figure 9 is a side view showing the state of the dam body 2 after the casting process St2. Figure 10 is a front view showing the state of the dam body 2 after the casting process St2. As shown in Figures 9 and 10, in the first casting process St21, a plurality of first anchor bolts 4111 are driven into the upstream surface 23 at the positions where the second plate-shaped member BM2 is to be placed. Specifically, the first anchor bolts 4111 are driven into the upstream surface 23 at the positions where the first structure 301 is fixed (a predetermined position on the first surface 231) and at the positions where the second structure 302 is fixed (a predetermined position on the second surface 232).

[0084] As shown in Figure 8, in the second casting process St22, a second anchor bolt 4121 with a third nut 4122 attached is driven into the upstream surface 23 of the dam body 2 perpendicular to the upstream surface 23. After the second anchor bolt 4121 is driven into the upstream surface 23, there is a gap between the third nut 4122 and the upstream surface 23. In this embodiment, after the second anchor bolt 4121 is driven in, the third plate-shaped member BM3 is inserted onto the second anchor bolt 4121. As shown in Figures 9 and 10, in the second casting process St22, a plurality of second anchor bolts 4121 are driven into the upstream surface 23 at the positions where the second plate-shaped member BM2 will be placed. Specifically, the second anchor bolts 4121 are driven into the upstream surface 23 at the positions where the first structure 301 is fixed (a predetermined position on the first surface 231) and the positions where the second structure 302 is fixed (a predetermined position on the second surface 232). Note that, for convenience, the first nut 4112, the third nut 4122, and the third plate-shaped member BM3 are omitted from the illustrations in Figures 9 and 10.

[0085] As shown in Figure 10, after the casting process St2, focusing on any four first anchor bolts 4111 that are close to each other on the upstream surface 23, in this embodiment, a rectangle Sq is formed by these four first anchor bolts 4111, with these four first anchor bolts 4111 as corners. Two second anchor bolts 4121, 4121 are cast on the first diagonal Di1 connecting two of the four first anchor bolts 4111, 4111 that form the rectangle Sq, and two second anchor bolts 4121, 4121 are cast on the second diagonal Di2 connecting the other two first anchor bolts 4111, 4111.

[0086] (First insertion process St3) After the casting process St2, that is, after the first casting process St21 and the second casting process St22, the first insertion process St3 is performed. Figure 11 shows the state of the first insertion process St3. As shown in Figure 11, in the first insertion process St3, the second plate-shaped member BM2 prepared in the preparation process St1 is inserted through the first anchor bolts 4111 and the second anchor bolts 4121 that were cast into the upstream surface 23 by the casting process St2. Specifically, with the first diagonal line Di1 shown in Figure 7 aligned with the first diagonal line Di1 shown in Figure 10, and the second diagonal line Di2 shown in Figure 7 aligned with the second diagonal line Di2 shown in Figure 10, the first anchor bolt 4111 is inserted through the hole Ha of the second plate-shaped member BM2, and the second anchor bolt 4121 is inserted through the first through hole Hb of the second plate-shaped member BM2. Furthermore, in the second plate-shaped member BM2 to which the support portion 415 is attached, the second plate-shaped member BM2 is inserted through the first anchor bolt 4111 and the second anchor bolt 4121 such that the support portion 415 is positioned vertically downward.

[0087] Subsequently, the positions of the first nut 4112 and the third nut 4122 are adjusted so that the side of the first nut 4112 opposite to the upstream surface 23 and the side of the third plate-shaped member BM3 opposite to the upstream surface 23 are at approximately the same height (distance from the upstream surface 23 in the out-of-plane direction of the upstream surface 23). As a result, as shown in Figures 11 and 12, the second plate-shaped member B M2 is supported from the upstream surface 23 side by the first nut 4112 and the third plate-shaped member BM3, and is positioned at a distance from the upstream surface 23 and approximately parallel to the upstream surface 23. Figure 12 is a side view showing the state of the dam body 2 after the first insertion process St3.

[0088] Thus, as shown in Figure 13, the entire rectangular Sq shown in Figure 10 is covered by the second plate-like member BM2 from the upstream side, completing the first insertion process St3. Figure 13 is a front view showing the state of the dam body 2 after the first insertion process St3.

[0089] (Second insertion process St4) Next, the second insertion process St4 is performed. Figure 14 shows the second insertion process St4 and the placement process St5. As shown in Figure 14, in the second insertion process St4, the second nut 4113 is inserted through the first anchor bolt 4111 which is driven into the upstream surface 23.

[0090] (Placement process St5) Next, the placement process St5 is performed. As shown in Figure 14, in the placement process St5, the positions of the first nuts 4112 and 4113 on the first anchor bolts 4111 are adjusted so that the second plate-shaped member BM2 is parallel to the upstream surface 23, and the second plate-shaped member BM2 is fixed by being sandwiched between the first nuts 4112 and 4113. As a result, for each of the multiple second plate-shaped members BM2 shown in Figure 13, four first holding parts 411 are provided that penetrate the vicinity of each of the four corners of the second plate-shaped member BM2 and are driven into the upstream surface 23, holding the second plate-shaped member BM2 spaced apart from the upstream surface 23 so that the second plate-shaped member BM2 is parallel to the upstream surface 23. Thus, through the arrangement process St5, multiple second plate-shaped members BM2 are arranged on the upstream surface 23 at positions parallel to the upstream surface 23 and spaced apart from the upstream surface 23 (that is, with a gap Ga formed between the upstream surface 23 and the second plate-shaped members BM2).

[0091] (Third insertion process St6) Next, the third insertion process St6 is performed. Figure 15 shows the third insertion process St6, the fourth insertion process St7, and the structure installation process St8. As shown in Figure 15, in the third insertion process St6, the first plate-shaped member BM1, which is attached to the first structure 301 and the second structure 302 (in this embodiment, the second structure 302 consisting only of the second part 302B) prepared in the preparation process St1, is inserted onto the first anchor bolt 4111 and the second anchor bolt 4121, for example, using heavy machinery. Specifically, the first plate-shaped member BM1 is inserted onto the first anchor bolt 4111 and the second anchor bolt 4121 so that each of the second through holes Hc formed in the first plate-shaped member BM1 communicates with each of the first through holes Hb formed in the second plate-shaped member BM2 in a one-to-one correspondence, and the first plate-shaped member BM1 is brought into surface contact with the second plate-shaped member BM2.

[0092] Furthermore, when the legs attached to the first plate-shaped member BM1 are the first leg portion 3011A and the second leg portion 3023, it is preferable to make the first plate-shaped member BM1 surface-contact with the second plate-shaped member BM2 such that the second portion 4151B of the main body portion 4151 of the support portion 415 contacts the lower end of the first plate-shaped member BM1. Also, as described above and as shown in Figure 4, an elongated hole 4151AH is formed in the first portion 4151A of the main body portion 4151 of the support portion 415, and the bolt 4152A of the fixing portion 4152 of the support portion 415 is inserted through this elongated hole 4151AH. Therefore, by loosening the nuts 4152B and 4152C of the fixing portion 4152, the main body portion 4151 can be moved along the extending direction of the elongated hole 4151AH. Therefore, the main body portion 4151 may be moved along the extending direction of the elongated hole 4151AH to bring the second portion 4151B of the support portion 415 into contact with the lower end of the first plate-shaped member BM1.

[0093] (Fourth insertion process St7) Next, the fourth insertion step St7 is performed. As shown in Figure 15, in the fourth insertion step St7, The fourth nut 4123 is inserted onto the second anchor bolt 4121. In this embodiment, before inserting the fourth nut 4123 onto the second anchor bolt 4121, the fourth plate-shaped member BM4 is inserted onto the second anchor bolt 4121 to cover the opening on the side opposite to the upstream surface 23 of the second through hole Hc formed in the first plate-shaped member BM1. Also in this embodiment, after inserting the fourth plate-shaped member BM4 onto the second anchor bolt 4121, and before inserting the fourth nut 4123 onto the second anchor bolt 4121, the fifth plate-shaped member BM5 (washer) is inserted onto the second anchor bolt 4121.

[0094] (Structure installation process St8) Next, the structure installation process St8 is performed. As shown in Figure 15, in the structure installation process St8, the third nut 4122 and the fourth nut 4123 are tightened so that surface contact between the first plate-shaped member BM1 and the second plate-shaped member BM2 is maintained. In this embodiment, the first plate-shaped member BM1, the second plate-shaped member BM2, the third plate-shaped member BM3, the fourth plate-shaped member BM4, and the fifth plate-shaped member BM5 are fixed to the first plate-shaped member BM1 and the second plate-shaped member BM2 by sandwiching and fixing them with the third nut 4122 and the fourth nut 4123, thereby maintaining surface contact between the first plate-shaped member BM1 and the second plate-shaped member BM2. In this way, multiple second holding portions 412 are formed that penetrate the first plate-shaped member BM1 and the second plate-shaped member BM2 and are cast into the upstream surface 23, maintaining surface contact between the first plate-shaped member BM1 and the second plate-shaped member BM2, and as a result, multiple fixing structures 41 (multiple fixing structures 41A, multiple fixing structures 41B, and multiple fixing structures 41C) are formed.

[0095] In this case, as described above, a certain amount of play is ensured between the inner surfaces of the second plate-shaped member BM2 and the first plate-shaped member BM1, which form the through holes Hb and Hc, and the second anchor bolt 4121 that penetrates the through holes Hb and Hc. Therefore, even if there are manufacturing errors and tolerances when forming the through holes Hb and Hc, or joining errors with respect to the legs 3011 and 3023 of the first plate-shaped member BM1, the position of the first plate-shaped member BM1 can be appropriately shifted relative to the second plate-shaped member BM2 so that no gap occurs between the first plate-shaped member BM1 and the second plate-shaped member BM2 due to such errors and tolerances. Accordingly, according to this embodiment, the occurrence of a gap between the first plate-shaped member BM1 and the second plate-shaped member BM2 can be more effectively suppressed.

[0096] As shown in Figure 16, the multiple first structures 301 are installed on the first surface 231 of the upstream surface 23 by performing the structure installation process St8 on each of the multiple first structures 301. Also, as shown in Figure 17, the second structures 302 (second parts 302B) are installed on the second surface 232 of the upstream surface 23 on each of the two second structures 302 (second parts 302B) in the transverse direction A. In this way, the structure installation process St8 forms a fixing section 4 consisting of multiple fixing structures 41, and in this embodiment, the multiple first structures 301 and the two second parts 302B (second structures 302) are installed on the dam body 2 by this fixing section 4 in a state in which gaps between the first plate-shaped member BM1 and the second plate-shaped member BM2 are suppressed.

[0097] (Filling process St9) Next, the filling process St9 is performed. In the filling process St9, a filling portion 413 is formed in the gap Ga between the upstream surface 23 and the second plate-shaped member BM2 installed in the structure installation process St8. For example, the opening between the lower end surface BM2a of the second plate-shaped member BM2 (see Figures 15 and 16) and the upstream surface 23, and the opening between both sides BM2b of the second plate-shaped member BM2 in the transverse direction A (see Figures 15 and 16) and the upstream surface 23, can be sealed with formwork, and a filling portion 413 shown in Figure 5 can be formed by pouring, for example, non-shrink mortar into the upper opening of the gap Ga and allowing it to solidify.

[0098] Next, as the final step, as shown in Figures 1 and 2, in the transverse direction A of the first surface 231 The first part 302A of the second structure 302 is fixed to both the first structure 301 on both sides and the second part 302B (second structure 302) directly above the first structure 301. Specifically, the flange F at the upper end of the first structure 301 and the flange F at the lower end of the first part 302A are joined by bolts, etc., and the flange F on the upstream side of the second part 302B and the flange F on the downstream side of the first part 302A are joined by bolts, etc.

[0099] Furthermore, as shown in Figures 1 and 3, the third structure 303 is fixed to each of the multiple first structures 301 located on sides other than both sides in the transverse direction A of the first surface 231. In addition, adjacent third structures 303 in the transverse direction A are fixed to each other, and adjacent first parts 302A and third structures 303 in the transverse direction A are fixed to each other. Specifically, the flange F at the upper end of the first structure 301 and the flange F at the lower end of the third structure 303 are joined by bolts or the like. Also, the flange F at one end (or the other end) of the first part 302A in the transverse direction A and the flange F at the other end (or the other end) of the third structure 303 in the transverse direction A are joined by bolts or the like. Furthermore, in the transverse direction A, the flange F at one end (or the other end) of one of the adjacent third structures 303, 303 is joined to the flange F at the other end (or the other end) of the other third structure 303 in the transverse direction A by bolts or the like.

[0100] Thus, the dam 1 of this embodiment is constructed.

[0101] According to this weir construction method, the steps of constructing the first holding part 411 and attaching the second plate-shaped member BM2 parallel to the upstream surface 23 by the first holding part 411 (first insertion step St3, second insertion step St4, and placement step St5) and constructing the second holding part 412 and maintaining surface contact between the second plate-shaped member BM2 and the first plate-shaped member BM1 by the second holding part (third insertion step St6, fourth insertion step St7, and structure installation step St8) can be carried out independently. Therefore, according to this weir construction method, it is possible to improve the accuracy in each of the former and latter steps, and as a result, it is possible to effectively suppress the occurrence of gaps at the fixing points between the capture body 3 and the weir body 2.

[0102] Furthermore, the above-mentioned preparation step St1 only needs to be completed before the structure installation step St8.

[0103] Although the present invention has been described above with reference to the above embodiments, the present invention is not limited thereto.

[0104] For example, in the above embodiment, an example was described in which the outer diameter Db of the third nut 4122 and the outer diameter Dc of the fourth nut 4123 are smaller than the hole diameter Da of the communication holes Hb and Hc. However, the outer diameter Db of the third nut 4122 and the outer diameter Dc of the fourth nut 4123 may be larger than the hole diameter Da of the communication holes Hb and Hc. In this case, when the third nut 4122 and the fourth nut 4123 are tightened, the third nut 4122 will contact the second plate-shaped member BM2 without entering the communication holes Hb and Hc, and the fourth nut 4123 will contact the first plate-shaped member BM1 without entering the communication holes Hb and Hc. Therefore, the first plate-shaped member BM1 and the second plate-shaped member BM2 can be sandwiched and fixed by the third nut 4122 and the fourth nut 4123 without providing the third plate-shaped member BM3, the fourth plate-shaped member BM4, and the fifth plate-shaped member BM5. In this case, in the second casting step St22 described above, it is not necessary to insert the third plate-shaped member BM3, which can cover the opening of the first through-hole Hb, onto the second anchor bolt 4121, and in the fourth insertion step St7, it is not necessary to insert the fourth plate-shaped member BM4, which can cover the opening of the second through-hole Hc, onto the second anchor bolt 4121 before inserting the fourth nut 4123 onto the second anchor bolt 4121.

[0105] Furthermore, in the above embodiment, each of the two sections DA, DA on the first diagonal Di1 In the above, an example was described in which four second retaining parts 412 are provided by forming one second through-hole Hc in each of two sections DA, DA located on the second diagonal Di2. In other words, in the above embodiment, an example was described in which two of the four second retaining parts 412, 412 are arranged on the first diagonal Di1 connecting two of the four first retaining parts 411, and the other two of the four second retaining parts 412, 412 are arranged on the second diagonal Di2 connecting the other two of the four first retaining parts 411, 411. However, the number and position of the second retaining parts 412 are not limited to the above embodiment. This point will be explained below.

[0106] For example, in the second leg portion 3023, instead of the four sections DA on the first diagonal Di1 and the second diagonal Di2, one second retaining portion 412 may be provided in each of the other four sections DA, or one second retaining portion 412 may be provided in each of five or more sections DA. In other words, four to eight second retaining portions 412 may be provided for each of the multiple second leg portions 3023.

[0107] On the other hand, as shown in Figures 2 and 3, the first leg portion 3011B is directly above the first leg portion 3011A, and the first leg portion 3011A is directly below the first leg portion 3011B. Therefore, if the second retaining portion 412 is provided in the first leg portion 3011A in addition to (or instead of) the four sections DA on the first diagonal Di1 and the second diagonal Di2, it is not necessary to consider providing the second retaining portion 412 in the uppermost section DAu (see Figure 4), taking into account that the installation of the second retaining portion 412 will be interfered with by the first leg portion 3011B. Furthermore, if, in addition to (or in lieu of) the four sections DA on the first diagonal Di1 and the second diagonal Di2, the first leg portion 3011B is provided with second retaining portions 412 in other sections DA, it is not necessary to consider providing a second retaining portion 412 in the lowest section DAd (see Figure 4), taking into account that the installation of the second retaining portion 412 may be interfered with by the first leg portion 3011A. In other words, four to seven second retaining portions 412 may be provided for each of the pair of first leg portions 3011A and 3011B.

[0108] Furthermore, in the above-described embodiment, the number and position of the second retaining portion 412 were discussed on the premise that eight ribs Ri are provided, but it goes without saying that the number and position of the second retaining portion 412 will change depending on the number of ribs Ri. For example, if no ribs Ri are provided, the number and position of the second retaining portion 412 can be adjusted as appropriate without being affected by the ribs Ri.

[0109] Those skilled in the art can appropriately modify the weir and weir construction method of the present invention in accordance with conventionally known knowledge. Such modifications, insofar as they still possess the configuration of the present invention, are of course included within the scope of the present invention. [Explanation of symbols]

[0110] 1... Dam, 2... Dam body, 3... Capture body, 4... Fixing part, 23... Upstream face, 41, 41A, 41B, 41C... Fixing structure, 231... First face, 232... Second face, 304... Capture part, 411... First holding part, 412... Second holding part, 413... Filling part, 415... Support part, 3011, 3011A, 3011B... Leg part (first leg part), 3023... Leg part (second leg part), 4111... First anchor bolt, 4112... First nut, 4113... Second nut, 4121... Second anchor bolt, 4122... Third nut, 4123... 4 nuts, 4124...4th nut, 4125...4th nut, 4152...fixing part, BM1...1st plate-shaped member, BM2...2nd plate-shaped member, BM3...3rd plate-shaped member, BM4...4th plate-shaped member, Bi1...1st diagonal, Bi2...2nd diagonal, Ga...gap, Hb...1st through hole, Hc...2nd through hole, St1...preparation process, St3...1st insertion process, St4...2nd insertion process, St5...placement process, St6...3rd insertion process, St7...4th insertion process, St8...structure installation process, St9...filling process, St21...1st casting process, S t22...Second concrete pouring process

Claims

1. A weir body positioned across a river, with a water passage formed on its upper side to allow the river's flow to pass through, A trapping body fixed to the upstream surface, which is the upstream side of the main body of the dam, The system includes a fixing part for fixing the capture body to the upstream surface, The aforementioned capture body is A capture section that captures the driftwood upstream of the dam body so that the driftwood does not pass through the water passage section, Multiple legs extending from the capturing portion toward the upstream surface, It includes a plate-shaped first plate-shaped member attached to the end of each of the plurality of legs opposite to the side of the capturing portion, The fixing portion includes a fixing structure provided corresponding to each of the plurality of legs, Each of the aforementioned fixed structures is A second plate-shaped member that is in surface contact with the upstream side surface of the first plate-shaped member, Multiple first holding portions are cast into the upstream surface, penetrating the vicinity of each corner of the second plate-shaped member, and holding the second plate-shaped member at a distance from the upstream surface so that the second plate-shaped member is parallel to the upstream surface, A plurality of second holding portions are cast into the upstream surface, penetrating the first plate-shaped member and the second plate-shaped member, and maintaining surface contact between the first plate-shaped member and the second plate-shaped member. A weir, comprising a filling portion that fills the gap between the second plate-like member and the upstream surface.

2. The first retaining part is, A first anchor bolt is driven into the upstream surface, extends in a direction perpendicular to the upstream surface, and penetrates the second plate-shaped member, A first nut is screwed onto the first anchor bolt on the upstream side of the second plate-shaped member, The second plate-shaped member includes a second nut screwed onto the first anchor bolt on the side opposite to the upstream surface, The second retaining part is, A second anchor bolt is driven into the upstream surface, extends in a direction perpendicular to the upstream surface, and penetrates the first plate-shaped member and the second plate-shaped member, A third nut is screwed onto the second anchor bolt on the upstream side of the second plate-shaped member, The first plate-like member includes a fourth nut screwed onto the second anchor bolt on the side opposite to the upstream side, The second plate-shaped member is held in place and fixed by the first nut and the second nut. The weir according to claim 1, wherein the first plate-shaped member and the second plate-shaped member are sandwiched and fixed by the third nut and the fourth nut.

3. The diameters of the first through-hole formed in the second plate-shaped member through which the second anchor bolt passes, and the diameters of the second through-hole formed in the first plate-shaped member through which the second anchor bolt passes, are larger than the outer diameters of the third nut and the fourth nut, respectively. The second retaining part is, A plate-shaped third plate-shaped member covers the opening on the upstream side of the first through hole, It includes a plate-shaped fourth plate-shaped member that covers the opening on the side of the second through hole opposite to the upstream side, The first plate-shaped member, the second plate-shaped member, the third plate-shaped member, and the fourth plate-shaped member are sandwiched and fixed by the third nut and the fourth nut, as described in claim 2. The dam.

4. The plurality of first holding parts include four first holding parts, The plurality of second holding parts include four second holding parts, Two of the four second holding parts are arranged on a first diagonal line connecting two of the four first holding parts. The weir according to any one of claims 1 to 3, wherein the other two of the four second retaining parts are arranged on a second diagonal line connecting the other two of the four first retaining parts.

5. The upstream surface of the dam body is The first surface, when viewed from the direction crossing the aforementioned river, slopes upward as it goes downward, and It includes a second surface connected to the upper end of the first surface and extending in the height direction of the dam body when viewed from a direction crossing the river, The dam according to any one of claims 1 to 3, wherein the plurality of legs include a plurality of first legs extending toward the first surface and a plurality of second legs extending toward the second surface.

6. The weir according to claim 5, wherein the plurality of first legs include pairs of first legs arranged on a straight line extending in the height direction when viewed from the direction of the river flow.

7. The weir according to claim 6, wherein four to seven second holding portions are provided for each of the pair of first legs.

8. The dam according to claim 6, wherein the fixing structure corresponding to the lower of the pair of first legs further includes a support that supports the first leg from below.

9. The dam according to claim 5, wherein four to eight of the second holding portions are provided for each of the plurality of second legs.

10. The dam according to claim 9, wherein the fixing structure corresponding to the second leg further includes a support portion that supports the second leg from below.

11. A preparation step of preparing a structure including a leg portion to which a plate-shaped first plate-shaped member is attached at the end, A first driving step involves driving a first anchor bolt, to which a first nut is attached, into the upstream surface, which is the upstream side of the weir body, which is positioned across the river and has a water passage formed on its upper side to allow the river flow to pass through. A second driving step involves driving a second anchor bolt, to which a third nut is attached, into the upstream surface perpendicular to the aforementioned upstream surface. After the first casting step and the second casting step, a first insertion step is performed in which a plate-shaped second plate-shaped member is inserted onto the first anchor bolt and the second anchor bolt, After the first insertion step, a second insertion step is performed in which the second nut is inserted onto the first anchor bolt, After the second insertion step, the positioning step involves adjusting the positions of the first nut and the second nut on the first anchor bolt so that the second plate-shaped member is parallel to the upstream surface, and then sandwiching the second plate-shaped member between the first nut and the second nut to position the second plate-shaped member at a location spaced apart from the upstream surface. After the arrangement step, a third insertion step is performed in which the first plate-shaped member of the structure is inserted onto the second anchor bolt and brought into surface contact with the second plate-shaped member, After the third insertion step, a fourth insertion step is performed in which the fourth nut is inserted onto the second anchor bolt. and, After the fourth insertion step, the third nut and the fourth nut are tightened to maintain surface contact between the first plate-shaped member and the second plate-shaped member, and the structure is installed in the dam body in a structure installation step, After the structural installation step, a filling step is performed to form a filling portion in the gap between the second plate-shaped member and the upstream surface, A method for constructing a dam, which includes the following features.

12. The diameters of the first through-hole formed in the second plate-shaped member through which the second anchor bolt passes, and the diameters of the second through-hole formed in the first plate-shaped member through which the second anchor bolt passes, are larger than the outer diameters of the third nut and the fourth nut, respectively. In the second casting step, a plate-shaped third plate member capable of covering the opening of the first through hole is inserted onto the second anchor bolt. In the fourth insertion step, before inserting the fourth nut onto the second anchor bolt, a plate-shaped fourth plate member capable of covering the opening of the second through hole is inserted onto the second anchor bolt. The method for constructing a dam according to claim 11, wherein in the structure installation step, the first plate-shaped member, the second plate-shaped member, the third plate-shaped member, and the fourth plate-shaped member are fixed by being sandwiched between the third nut and the fourth nut.

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