JP6366780B2 - Precast concrete buried frame for construction of fishway - Google Patents

Description

  The present invention relates to a fishway provided in a river.

  Rivers are provided with artificial structures such as dams, sabo dams, and weirs for the purpose of flood control and water use. Fish and aquatic animals that inhabit the rivers run up the river, but such artificial structures have a large drop in water, so the upstream is hindered and affects the river ecosystem. Therefore, when constructing such an artificial structure, a fishway is provided in parallel with the river so that fish and aquatic animals can bypass the artificial structure by going up the fishway. In general, a fishway is composed of a channel with a predetermined width, and the channel is provided with a number of steps in the flow direction so that the drop of water per step is small, and the water flow is gently between each step. A predetermined depression is formed so as to be. Therefore, fish and aquatic animals can easily go up the fishway by repeatedly going up the steps with small heads while repeating the waiting in each depression.

JP 2002-317429 A

  Various types of fish paths have been proposed according to the purpose. For example, Patent Document 1 proposes a fish path that allows fish to easily run up even when the river flow is small. In the fishway described in Patent Document 1, the water channel is formed of a plurality of steps, and each step is formed on a climbing slope inclined at an angle of 20 to 25 ° and the climbing slope. It is comprised from the dam part which is connected and becomes a hill, and the inclination part of the angle of 40-65 degrees connected downstream from this dam part. A cushion portion in which water stays is formed between the two adjacent step portions, that is, a portion surrounded by the inclined portion of the upstream step portion and the rising slope of the downstream step portion. Has been. Accordingly, the water flowing through the fishway flows through the inclined portion and stays in the cushion portion, and gently moves over the dam portion and flows down the inclined portion of the next stage. Since the water flows in this way, it is easy for the fish to go up, and even if the amount of river water is small, it will not hinder the fish from going up.

  As described above, the fishway has a large number of steps in the flow direction of the water channel, and the drop of water in each step is small, and there is a portion where the water flow stays or flows gently between each step. Is formed. Because it is formed in this way, fish and aquatic organisms can easily go up the fishway. However, there is also a problem that stones and earth and sand are easily deposited. This problem is particularly serious when a large amount of sediment is washed away from the upstream due to heavy rain. If stones or earth and sand accumulate on the fishway, the flow will be hindered and the purpose of the fishway will not be fulfilled. Therefore, the shape of the fishway is devised so that stones and earth and sand are hard to deposit, or even if they are deposited, they flow easily downstream by water flow. In the fishway described in Patent Document 1, each step portion is made up of a slope, a dam portion, and an inclined portion, that is, since there is no surface perpendicular to the flow direction, stones and earth and sand have accumulated on the cushion portion. However, once the water flows with a strong water flow, they will be swept away. That is, it can be said that the fishway described in Patent Document 1 is also a fishway where stones and earth and sand are relatively hard to accumulate.

  Prof. Yoichi Yasuda of the Faculty of Science and Engineering, Nihon University has proposed a fishway that is hard to accumulate stones and earth and sand as follows. In other words, the steps provided in a number of stages in the flow direction of the water channel are the rising slope part inclined so as to rise, the dam part of the hill connected to the rising slope part, and the downstream side of the weir part And a downwardly inclined surface portion that is inclined downward. The rising slope is formed with a gradient of 1 in the vertical direction and 0.2 in the horizontal direction, that is, a gradient of 2 minutes, the weir is formed horizontally, and the falling slope is 1 in the vertical direction. On the other hand, the horizontal direction is formed with a gradient of 1, that is, a gradient of 10%. In addition, the embankment-shaped walls that are provided on the left and right sides of the water channel so that water does not overflow from the side, that is, the water bank, are not vertical as in the conventional fishway, but 10% toward the center of the water channel. It is formed in the gradient. Therefore, even if stones and earth and sand flow in, it is easy to flow out and is difficult to deposit. Moreover, even if they are accumulated, if the water flows with a strong water flow, the accumulated stones and earth and sand will be washed away downstream, or will be pushed out from the side of the fishway so as to overflow from the bank. In other words, it is difficult to deposit stones and earth and sand, and even if it is deposited, it is a fishway that discharges very easily.

  Both the fishway described in Patent Document 1 and the fishway proposed by researchers at universities, etc. are difficult to accumulate stones and earth and sand, and even if they accumulate, they are easily washed away by strong water flow. The objective can be achieved. In other words, these fishways have excellent performance as fishways. However, there is a problem in that it is difficult to construct a complex-shaped fishway having a large number of inclined portions. The fishway is constructed from reinforced concrete, but the fishway is constructed as follows. That is, a so-called deadline drainage is implemented in which a sandbag is placed upstream so that water does not enter the area where the fishway is to be constructed, and the water flow is released to the side. Next, a plurality of rebars are bound to form a fishway shape. Build a formwork. Place concrete and wait for setting. Remove the formwork and remove the sandbag to get a fishway. In such a conventional construction method, it is time-consuming work for rebar binding and formwork construction, especially in the case of the fishway described in Patent Document 1 and the fishway proposed by the inventor of the present invention. Takes many weeks because it has many inclined parts and its shape is complicated. This increases the construction cost of the fishway. In addition, if the construction period is long, the risk of the river increasing due to rainfall or the like during that period increases, and the risk of disaster increases. In addition, a wooden frame is generally used for the formwork, but a large amount of wooden frame is necessary to construct the fishway, and the wooden frame can usually be reused about 3 times, but for specially shaped fishway If it is used, it cannot be diverted to other uses and must be discarded after one use. This increases the cost, including the cost of discarding the wooden frame. Furthermore, when the frame gradient is less than 73 °, there is a problem that bubbles in the concrete are difficult to escape when placing the concrete. In this case, it is necessary to make a hole that allows air to escape into the formwork, or after the concrete has solidified and solidified to remove the formwork, it is necessary to repair by filling the bubbles with concrete.

  The present invention has been made in view of the above-described problems. Specifically, even when a complex-shaped fishway having a large number of inclined portions is constructed, it can be easily constructed in a short period of time. Precast concrete embedment frame for construction of fishways that can reduce the risk of disaster, reduce the cost and useless formwork, and is less susceptible to the generation of air bubbles when placing concrete The purpose is to provide.

In order to achieve the above object, the present invention is configured as a precast concrete embedment frame for construction of a fishway. The target fishway is composed of right and left bank portions forming the right and left sides of the fishway, and a plurality of steps provided between both bank portions so as to cross the flow direction. Each step portion is composed of a rising slope portion rising at a predetermined slope, a horizontal dam portion connected to the upward slope, and a downward slope portion falling at a predetermined slope from the dam portion. A fishway. In the present invention, the embedded frame includes a step frame portion that constitutes a part of one step. If such a frame for a step portion is installed as a formwork and concrete is placed, a fishway can be constructed.

That is, the invention according to claim 1 includes a right bank portion having a bank shape provided on the right side in the flow direction, a left bank portion similarly having a bank shape provided on the left side in the flow direction, and a flow direction. A plurality of steps provided between the right bank and the left bank so that each of the steps rises at a predetermined inclination, and the rising inclination A precast concrete embedment frame for constructing the fishway against a fishway composed of a horizontal weir connected to the dam and a downwardly inclined part descending from the weir with a predetermined inclination The embedment frame is configured as a precast concrete embedment frame for construction of a fishway, characterized in that the embedment frame includes a step portion frame portion having a predetermined lateral width that constitutes a part of the step portion for one step .

A second aspect of the present invention is the embedded frame according to the first aspect, wherein the stepped frame portion includes rectangular first to third plate portions having the same width and different lengths as viewed from the side. The first and third plate portions corresponding to the trapezoidal legs are respectively formed as the upward inclined portion and the downward inclined portion. And the second plate portion corresponding to the upper base of the trapezoid corresponds to the weir portion, respectively, and is configured as a precast concrete embedment frame for construction of a fishway.
A third aspect of the present invention is the precast concrete for construction of a fishway, characterized in that in the embedded frame according to the second aspect , the step frame portion is hollowed in the second plate portion. It is configured as a buried frame.
According to a fourth aspect of the present invention, in the fishway constructed by the buried frame according to any one of the first to third aspects, the rising slope of the step portion is inclined to approximately 2 minutes, and the downward slope It is constructed as a precast concrete embedment frame for construction of a fishway, characterized in that the portion is formed with a slope of approximately 10%.

As described above, the present invention is configured as a precast concrete embedment frame for construction of a fishway. That is, it is configured as a so-called discard frame. The target fishway is composed of a right bank and a left bank that form the right and left sides of the fishway, and a plurality of steps provided between both banks so as to cross the flow direction. Each step portion is composed of a rising slope portion rising at a predetermined slope, a horizontal dam portion connected to the upward slope, and a downward slope portion falling at a predetermined slope from the dam portion. It is a fishway. And the embedding frame of this invention is equipped with the step part frame part which comprises a part of said step part for one step. Therefore, installing a plurality of buried frame in a predetermined arrangement, and the mold can be easily installed by utilizing the step portion for frame section. Therefore, it is possible to construct a fishway much more efficiently than the case where all the molds are assembled from the beginning and concrete is cast. In particular, the fishway that is the object of construction has a complicated shape because the step portion is provided with an upwardly inclined portion and a downwardly inclined portion. A mold for obtaining such a complicated shape is inevitably complicated, but it can be handled only by providing the embedded frame of the present invention, and it is not necessary to provide a mold. This makes it possible to construct a fishway in a short time and reduce the risk of disaster. Furthermore, only a small amount of mold is wasted, and the cost can be reduced. And since the above-mentioned formwork only needs to be provided between the buried frames, the influence of air bubbles generated when placing concrete is minimized. In other words, even if air bubbles remain after the concrete has solidified and the formwork has been removed, such portions are only part of the fishway, so it is only necessary to repair those bubbles by filling them with concrete.

According to another invention, the stepped frame portions are arranged so that the rectangular first to third plate portions having the same width and different lengths have a substantially trapezoidal shape as a whole when viewed from the side. The first and third plate portions corresponding to the trapezoidal legs are respectively formed as an upward inclined portion and the downward inclined portion, and the second plate portion corresponding to the upper base of the trapezoid is formed in a combined shape. It corresponds to each weir part. If it does so, a step part frame part can be piled up and conveyed. Therefore, a large number of embedded frames can be transported efficiently, and the transport cost can be reduced.

According to another invention, since the step frame is hollowed in the second plate portion, it can be used as a placement hole when placing concrete, and air can easily escape. . Further, according to another invention, the fishway constructed by the buried frame is formed such that the rising slope part of the step part has a slope of about 2 minutes and the downward slope part has a slope of about 10%. In such a fishway, stones and earth and sand are hard to accumulate on the fishway, and even if they accumulate, they are easily discharged when a strong water stream flows. According to the present invention, such a high-performance fishway can be easily constructed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the fishway constructed | assembled with the embedment frame made from the precast concrete for fishway construction which concerns on embodiment of this invention, The (a) is a perspective view of a fishway, The (i) Cross section XX in (a) It is sectional drawing cut | disconnected by. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the right side frame of the precast concrete embedment frame for fishway construction which concerns on embodiment of this invention, The (a), (b) is the perspective view and side view of the step part frame part which comprise the right side frame, The (c) to (e) are a perspective view, a plan view, and a side part of the right bank part frame part constituting the right frame, respectively. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the right side frame of the precast concrete embedment frame for fishway construction which concerns on embodiment of this invention, The (a) shows a mode that a right side frame is assembled from the frame part for steps, and the frame part for right bank parts. The perspective views, (a) to (d) are a perspective view, a side view and a front view of the assembled right side frame, respectively. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the method of constructing a fishway by the precast concrete embedment frame for fishway construction concerning an embodiment of the invention, and (a) and (i) are perspective views showing each process. It is a perspective view of the fishway which concerns on the other form which can be constructed using the embedment frame made from the precast concrete for fishway construction which concerns on embodiment of this invention.

  Embodiments of the present invention will be described below. Although the present invention relates to a precast concrete embedment frame for construction of a fishway, a fishway constructed by the embedment frame according to the present embodiment will be described first. The fishway 1 targeted by the present invention is gently inclined so that the overall gradient is 5 to 10 °, and corresponds to the right hand or right bank as viewed in the flow direction, as shown in FIG. A right bank 2, a left bank 3 corresponding to the left bank, and a plurality of steps 5, 5, ... provided between the right bank 2 and the left bank 3 so as to cross the flow direction It is composed of Both the right bank portion 2 and the left bank portion 3 are inclined toward the center, and these gradients are formed in a so-called 10% gradient in which the vertical direction is 1 and the horizontal direction is 1. . The step portion 5 includes a rising slope portion 7 that rises at a slightly steep angle, a dam portion 8 that is connected to the rising slope portion 7, and a gentle slope that is connected downstream from the weir portion 8. And a downwardly inclined portion 9. In the present embodiment, the rising slope portion 7 is formed with a so-called gradient of 2 minutes in which the vertical direction is 1 and the horizontal direction is 0.2, the weir portion 8 is horizontal, and the falling slope portion 9 is 10%. It is formed in the gradient. Further, horizontal bottom portions 10, 10,... Are provided between the step portions 5, 5,. Since various portions are inclined as described above, it is difficult for stones and earth and sand to accumulate on the fishway 1, and even if they accumulate, they are easily washed away by the water flow.

  Next, an embedded frame according to the present embodiment for constructing such a fishway 1 will be described. The embedment frame according to the present embodiment is made of precast concrete, and includes a right frame that forms part of the right side of the fishway 1 and a left frame that forms part of the left side. Since the right frame and the left frame are mirror images of each other, only the right frame will be described below. The right frame 12 of the embedded frame according to the present embodiment is shown in the step frame 13 shown in FIGS. 2A and 2A and FIGS. 2C to 2O. And the right bank portion frame portion 14. The step portion frame portion 13 is a frame that constitutes the right side portion of the step portion 5 for one step of the fishway 1. The step portion frame portion 13 includes first to third plate portions 16, 17, and 18 that are coupled to each other and have the same lateral width and different lengths. These first to third plate portions 16, 17, and 18 are coupled to each other so as to exhibit a trapezoidal shape when viewed from the side, and the first plate portion 16 is formed on the step portion 5 of the fishway 1. The second inclined plate 7 corresponds to the rising ramp 7, the second plate 17 corresponds to the weir 8, and the third plate 18 corresponds to the falling inclined portion 9. Accordingly, when the step frame 13 is placed on the installation surface with a gradient of 5 to 10 ° so that the second plate portion 17 is horizontal, the first plate portion 16 has a gradient of 2 minutes. The third plate portion 18 has a 10% gradient. That is, the angle formed by the third plate portion 18 and the horizontal plane is 45 °. The first plate portion 17 is shorter than the third plate portion 18 so that the first plate portion 17 can be installed on an installation surface having a gradient. In such a step frame 13, a hollow 19 is formed as a placement hole for placing concrete on the second plate portion 17. As can be seen from FIG. 2A, since the step frame 13 is formed hollow, it is possible to stack a plurality of step frames 13, 13,. it can. Therefore, it can be transported efficiently.

  The right dyke frame portion 14 constituting the right frame 12 is a frame that constitutes a part of the right dyke portion 2 of the fishway 1, as shown in FIG. It is composed of a parallelogram concrete plate. Then, it is cut out in a trapezoidal shape from the portion corresponding to the base of the parallelogram. The portion cut into the trapezoidal shape has a shape similar to the trapezoidal shape of the step frame 13, but the angle is slightly different. For example, the third plate portion 18 of the step portion frame portion 13 is formed at an angle of 45 ° with respect to the horizontal plane, but the portion of the reference numeral 21 corresponding to the third plate portion 18 is more than 45 °. The angle is slightly larger. Similarly, the portion denoted by reference numeral 22 corresponding to the first plate portion 16 is slightly larger than the angle of the first plate portion 16. Therefore, as will be described below, when the right bank portion 14 is placed on the step frame 13, the right bank portion 14 is stable in a state of being inclined with respect to the step frame 13. Will do. Since the right bank portion frame portion 14 also has a plate shape, a plurality of sheets can be stacked and stacked, and can be efficiently transported.

  The right frame 12 according to the present embodiment is assembled as follows. That is, as shown in FIG. 3A, the right bank portion frame portion 14 is placed on the step portion frame portion 13. At this time, the cut portion of the right bank portion frame portion 14 is fitted into the step portion frame portion 13. Then, the lowermost portions of the reference numerals 21 and 22 are in contact with the third and first plate portions 18 and 16 of the step portion frame portion 13. Next, as shown by the arrow Y, the right bank portion frame portion 14 is tilted around the contacted portion. Then, as shown in FIGS. 3A to 3D, the right bank portion frame portion 14 is stabilized in a state of being inclined by 45 °. In other words, the right bank portion frame portion 14 is inclined to a gradient of 10% and is stabilized.

  Although the description of the left side frame of the buried frame has been omitted, the left side frame, like the right side frame 12, is provided with a step portion frame portion that constitutes a part of the left side of the step portion 5 of the fishway 1 and the left bank portion 3. It consists of the left bank part frame part which comprises a part. And a left side frame is comprised by mounting the left side bank part frame part on the step part frame part.

  4, a method for constructing the fishway 1 from a plurality of right side frames 12, 12,... And the same number of left side frames 12 ', 12',. Similar to the conventional construction method, a so-called deadline drainage is carried out in which a sandbag is placed upstream so that water does not enter the area where the fishway 1 is to be constructed, and the water flow is released to the side. Next, the ground is leveled to construct the fishway 1. Alternatively, concrete is cast so as to have an inclination of 5 to 10 ° to obtain an installation surface. Next, as shown in FIG. 4A, the right frames 12, 12,... And the left frames 12 ', 12',. At this time, the right frame 12 and the left frame 12 ′ to be arbitrarily paired are arranged so as to have a predetermined interval and aligned in the lateral direction, and the front and rear right frames 12, 12 and the left frame 12 ′, 12 'is also arranged at a predetermined interval. When the right side frames 12, 12,..., The left side frames 12 ′, 12 ′,... Are arranged in this manner, the step frame portions 13, 13,. , 14,..., Left bank portion frame portions 14 ′, 14 ′,... Can be placed easily on step frame portions 13, 13,.

  Next, as shown in FIG. 4A, the molds K1 and K2 are installed between the adjacent right frame 12 and left frame 12 '. These formwork K1, K2 may be comprised from a wooden frame, and may be comprised from a concrete board as an embedment frame. In this embodiment, a wooden frame is used. The mold frames K1 and K2 can be easily fixed because they are pressed against the first and third plate portions 16 and 18 of the stepped frame portions 13 of the adjacent right frame 12 and left frame 12 ′. Can be installed. A mold frame K3 is provided between the right bank portion frame portions 14 and 14 of the right frame 12 and 12 adjacent to each other in the flow direction. Then, a mold frame K4 is provided on the right side of the right frames 12, 12,. Next, a mold K5 is provided between the left bank portions 14 'and 14' of the left frames 12 'and 12' adjacent in the flow direction. A mold K6 is provided on the left side of the left frames 12 'and 12'. Place concrete. Then, concrete is filled into the hollow portions of the right side frames 12, 12,..., The left side frames 12 ', 12',. When the concrete has set and solidified, the molds K1, K2,... Are removed. Although not shown in the drawing, concrete is placed between two adjacent steps to form the bottom portions 10 and 10. Fill with concrete if necessary. The fishway 1 shown in FIG. 1 is obtained.

  The right side frame 12, 12,... And the left side frame 12 ′, 12 ′,... Are both described in the embedded frame according to the present embodiment, but one of these embedded frames, for example, the left side frame 12 ′. It is also possible to construct a fishway using only 12 ′,. For example, FIG. 5 shows an example of such a fishway 1 '. In this fishway 1 ', the right bank 2' is vertical. A method for constructing the fishway 1 ′ shown in FIG. 5 from only the left side frames 12 ′, 12 ′,.

  The shape of the buried frame can also be modified. In other words, the buried frame according to the present embodiment, that is, the right frame 12, 12,..., The left frame 12 ′, 12 ′,. Is formed. The shape of the fishway 1 is ideal because it is difficult for stones and earth and sand to accumulate. However, the present invention is not limited to such a fishway 1, and even a fishway having another shape with a slightly different gradient can be accommodated by the buried frame according to the present invention. That is, if the shape of the right and left frames is determined according to the shape of the fishway to be constructed, and a plurality of such right and left frames are manufactured from precast concrete, a desired fishway can be easily constructed. Can do.

DESCRIPTION OF SYMBOLS 1 Fishway 2 Right side bank part 3 Left side bank part 5 Step part 7 Ascending slope part 8 Dam part 9 Falling slope part 10 Bottom part 12 Right side frame 12 'Left side frame 13 Step part frame part 14 Right side bank part 14' Left bank Frame portion 16 First plate portion 17 Second plate portion 18 Third plate portion 19

Claims (4)

A right levee portion having a levee shape provided on the right side of the flow direction, a left levee portion similarly having a levee shape provided on the left side of the flow direction, the right levee portion so as to cross the flow direction, and the A plurality of step portions provided between the left bank portions, each of the step portions rising up with a predetermined inclination, and a horizontal weir portion connected to the upward inclination , A precast concrete embedment frame for constructing the fishway, with respect to the fishway composed of a downwardly inclined part falling from the weir part with a predetermined inclination,
The embedment frame is a precast concrete embedment frame for construction of a fishway, characterized in that the embedment frame is composed of a step portion frame portion having a predetermined width that constitutes a part of the step portion for one step . 2. The embedded frame according to claim 1 , wherein the stepped frame portion has a rectangular substantially flat base when the rectangular first to third plate portions having the same width and different lengths are viewed from the side. The first and third plate portions corresponding to the trapezoidal legs are respectively formed on the rising slope portion and the falling slope portion, and on the top of the trapezoid. precast concrete embedded frame fishway construction, characterized in that said second plate portion corresponding respectively correspond to the weir portion in the bottom. 3. The precast concrete embedment frame for construction of a fishway according to claim 2 , wherein the step frame is cut out in the second plate portion. The fishway constructed by the embedding frame according to any one of claims 1 to 3, wherein the rising slope part of the step part is formed with a slope of approximately 2 minutes and the falling slope part is formed with a slope of approximately 10%. precast concrete embedded frame for fish passage construction, wherein the being.

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