JP2020200583A - Discharge system and method of sediment - Google Patents

Abstract

To provide a discharge system and a method of sediment easily applicable to various sites, and allowing discharge of the sediment to downstream areas of a dam without accumulating the sediment for a long period, while suppressing cost required for a facility.SOLUTION: In a normal time, a water introducing passage 4 is closed by a water control gate 5 of a sand discharge facility 3 provided on a weir 2 provided in the upstream area of a dam 18, to thereby allow overflow of water W upstream of the weir 2 and introduce into a water reservoir 19 between the weir 2 and the dam 18. In a case of a large amount of the upstream water W due to heavy rainfall or the like, the water introducing passage 4 is opened to introduce the water W upstream of the weir 2 together with sediment S into the water introducing passage 4, and the water level upstream of the weir 2 is lowered than the height of the weir 2, and the sediment S introduced into the water introducing passage 4 is sucked by a pump 9, and transferred to a sand discharge passage 7 connected to the water introducing passage 4. The sediment S is discharged to a downstream area of the dam 18 through a sand discharge bypass tunnel 8 with a gradient greater than a normal gradient, together with the upstream water W passing through the water introducing passage 4 and flowing through the sand discharge passage 7.SELECTED DRAWING: Figure 8

Description

The present invention relates to a sediment discharge system and method, and more specifically, it is easy to apply to various sites, and while suppressing the cost required for construction and operation, the sediment on the bottom of the water in the upstream area of the dam is not deposited for a long period of time. It relates to a sediment discharge system and method that can be discharged to the downstream area of the dam.

Sediment flows into the dam's reservoir from upstream rivers, reducing the reservoir capacity over time, increasing flood risk due to riverbed rise in the upstream area of the dam, and sediment supply from rivers in the downstream area of the dam. Due to the decline in the riverbed, problems such as riverbed decline and coastline retreat have arisen. Therefore, the sediment in the reservoir of the dam is discharged to the downstream area of the dam by, for example, a sand removal bypass tunnel or a sand removal gate installed in the dam.

The slope of the sand drainage bypass tunnel that extends between the upper end of the reservoir reservoir of the dam and the downstream area of the dam is required to be increased to some extent in order to discharge sediment smoothly, so the site where this tunnel can be applied is limited. Be done. In addition, since the amount of sediment drawn into this tunnel depends on the bed load of the riverbed flow velocity upstream, the slurry concentration of turbid water in the tunnel cannot be controlled. Along with this, the cross-sectional area of the tunnel becomes large and the construction cost may become large.

In the case of a sand drainage gate, if it takes time to recover the lowered water level of the reservoir after opening the gate and draining sand, the water utilization will be greatly affected. Therefore, it is necessary that the amount of inflow water from the river is sufficient for the water storage capacity, and the sites where the sand removal gate can be applied are very limited.

Various methods have been proposed for flowing sediment in water using hydrostatic pressure (see, for example, Patent Document 1). With the method using hydrostatic pressure in this way, it may not be possible to smoothly flow the sediment due to problems such as clogging of the sand discharge pipe. In addition, since the sediment once deposited in the reservoir is sent to the downstream area again, there is a concern that the sediment will become sludge and adversely affect the rivers in the downstream area. Due to such various problems, it has not been put into practical use.

Japanese Unexamined Patent Publication No. 2000-12050

An object of the present invention is to provide sediment that can be easily applied to various sites, suppresses the cost required for construction and operation, and can be discharged to the downstream area of the dam without depositing the sediment on the bottom of the water in the upstream area of the dam for a long period of time. To provide emission systems and methods.

In order to achieve the above object, the sediment discharge system of the present invention is derived from a weir installed in the upstream area of the dam, a sand discharge facility installed at a predetermined position in the extending direction of the weir, and this sand discharge facility. A sediment discharge system having a sand drainage channel extending to the downstream side and a sand drainage bypass tunnel having a slope equal to or higher than a specified gradient connecting the sand drainage channel and the downstream area of the dam. The pump has a lead-in flow path connected to the sand drainage channel, a water control gate for opening and closing the lead-in flow path, and a pump arranged on the upstream side of the water control gate in the lead-in flow path. The service is provided by providing a conduit extending between the discharge port and the sand drainage channel, the water control gate, and a control unit for controlling the pump, and closing the lead-in flow path by the water control gate. Water on the upstream side of the weir crosses the weir and flows into the reservoir between the weir and the dam, and the water control gate opens the lead-in flow path on the upstream side of the weir. Water flows into the lead-in flow path together with sediment generated by sand flowing from the upstream side, and the water level on the upstream side of the weir is lower than the height of the weir, so that the draw-in flow The sediment that has flowed into the path can be sucked into the pump and transferred to the sand drainage path by a route that passes through the pipeline and a route that passes through the lead-in flow path, thereby enabling the discharge. It is characterized in that the sediment transferred to the sand channel and the water on the upstream side are discharged to the downstream area of the dam through the sand drain bypass tunnel.

In the method for discharging sediment of the present invention, a sand removal facility is installed at a predetermined position in the extending direction of a weir installed in the upstream area of the dam, and a sand discharge channel is extended downstream from this sand removal facility. , This sand removal path is connected to the downstream area of the dam via a sand removal bypass tunnel having a slope equal to or higher than the specified gradient, and the sand removal facility is opened and closed with the lead-in flow path connected to the sand drainage channel and the lead-in flow path. A water control gate and a pump arranged on the upstream side of the water control gate in the lead-in flow path are provided, and the lead-in flow path is closed by the water control gate to be upstream of the weir. The water on the side is allowed to flow over the weir into the reservoir between the weir and the dam, and the lead-in flow path is opened by the water control gate to allow the water on the upstream side of the weir to flow upstream. The sediment generated by the sand flowing from the weir was allowed to flow into the lead-in flow path, and the water level on the upstream side of the weir was lowered below the height of the weir. , The sediment and the sediment transferred to the dam by enabling the route to be sucked by the pump and passing through the pipeline and the route to pass through the lead-in flow path to be transferred to the dam. It is characterized in that the water on the upstream side is discharged to the downstream area of the dam through the sand drainage bypass tunnel.

According to the present invention, when the amount of water on the upstream side increases due to heavy rain or the like, the water on the upstream side of the weir is drawn in together with the sediment on the upstream side of the weir by opening the lead-in flow path by the water control gate. It can flow into the road and the water level on the upstream side of the weir can be lowered below the height of the weir. In the lead-in flow path, the inflowed sediment is sucked by a pump, transferred to the sand drainage channel connected to the lead-in channel, and together with the water flowing through the lead-in channel and the sand drainage channel, the sand drainage bypass It can be discharged to the downstream area of the dam through the tunnel. By using the sand removal channel in this way, it becomes easy to apply the sand removal bypass tunnel having a specified gradient or more even at the site under various conditions.

In addition, the sand removal bypass tunnel can be shortened by removing sand with a pump. Since turbid water having a high sediment content can flow through the sand removal bypass tunnel, the cross-sectional area of the tunnel can be reduced as compared with the case where the slurry concentration of turbid water cannot be controlled. Therefore, it is advantageous to reduce the cost required for the construction of the sand removal bypass tunnel. In addition, since the transfer of sediment by the pump and the transfer of sediment by the head difference are used together, it is also advantageous to reduce the cost required for operating the equipment.

Furthermore, the sediment can be discharged to the downstream area of the dam at an appropriate timing when the sediment increases, such as when the flow rate of water on the upstream side of the weir increases. Along with this, it is advantageous to avoid a state in which sediment is accumulated for a long period of time.

It is explanatory drawing which illustrates the whole outline of the sedimentation discharge system of this invention in a plan view. It is explanatory drawing which schematically exemplifies the discharge system of FIG. 1 in the vertical cross-sectional view. It is explanatory drawing which illustrates the sand removal facility and a weir of FIG. 1 in a plan view. It is explanatory drawing which enlarges the vicinity of the sand removal facility of FIG. FIG. 4 is a sectional view taken along the line AA of FIG. FIG. 4 is a cross-sectional view taken along the line BB of FIG. It is explanatory drawing which illustrates the sand removal facility of FIG. 4 from the front view. It is explanatory drawing which illustrates the state which raised the water control gate of FIG. 6 and opened the lead-in flow path. It is explanatory drawing which illustrates the sand removal facility of FIG. 8 in a plan view. It is explanatory drawing which illustrates the state which the drifting thing is trapped in the screen of FIG. It is explanatory drawing which illustrates the state which raised the screen of FIG. It is explanatory drawing which illustrates the sand removal facility which made the pump of FIG. 6 another installation form. It is explanatory drawing which illustrates the sand removal facility of FIG. 12 in a plan view. It is explanatory drawing which illustrates the state which raised the water control gate of FIG. 12, and opened the lead-in flow path. It is explanatory drawing which illustrates the sand removal facility of FIG. 14 in a plan view. It is explanatory drawing which illustrates another arrangement form of a sand removal facility in a plan view. It is explanatory drawing which illustrates the other arrangement form of a sand removal facility in a plan view.

Hereinafter, the sediment discharge system and method of the present invention will be described based on the embodiment shown in the figure.

The sediment discharge system 1 of the present invention illustrated in FIGS. 1 and 2 prevents sediment flowing in the upstream river 20a of the dam 18 from flowing into and accumulating in the reservoir 19 dammed by the dam 18. To do. That is, in this discharge system 1, the sediment S at the bottom of the upstream river 20a is passed through the sand drainage channel 7 and the sand drainage bypass tunnel 8 to the downstream river of the dam 18 so that a large amount of sediment S is not generated in the reservoir 19. Discharge to 20b. The sand removal passage 7 is, for example, a flow path whose upper surface is open, or a flow path whose upper surface can be opened by removing the lid. The lower end of the sand removal passage 7 is connected to the entrance 8a of the sand removal bypass tunnel 8, and the outlet 8b of the sand removal bypass tunnel 8 opens to the downstream river 20b.

The discharge system 1 includes a weir 2 installed across the upstream river 20a, a sand removal facility 3 installed at a predetermined position in the extending direction of the weir 2, and a sand removal facility 3 extending downstream from the sand removal facility 3. It has a sand removal channel 7 to be used, and a sand removal bypass tunnel 8 having a predetermined gradient or more connecting the sand removal channel 7 and the downstream river 20b. A reservoir 19 exists between the dam 18 and the weir 2.

In addition, the above-specified gradient means 1/100 or more required in the "Dam Reservoir Sediment Management Guide (Draft)" established by the Ministry of Land, Infrastructure, Transport and Tourism.

As illustrated in FIGS. 3 to 7, the sand removal facility 3 has a lead-in flow path 4 connected to the sand drainage passage 7, a water control gate 5 for opening and closing the lead-in flow path 4, and a lead-in flow path 4. It has a pump 9 arranged on the upstream side of the water control gate 5. Further, it includes a pipeline 10 extending from the discharge port 9e of the pump 9 to the sand drainage channel 7, and a control unit 16 for controlling the operation of the water control gate 5 and the pump 9. A concentration sensor 10a for detecting the sediment concentration of muddy water flowing through the pipeline 10 is attached in the middle of the pipeline 10. The density data detected by the density sensor 10a is sequentially input to the control unit 16.

In this embodiment, the lead-in flow path 4 is provided with a water-permeable and sand-permeable screen 12 arranged on the upstream side of the pump 9. Further, a water level sensor 14 for detecting the water level of the lead-in flow path 4 and a surveillance camera 15 for photographing the periphery of the screen 12 are installed. The water level data detected by the water level sensor 14 is sequentially input to the control unit 16. A management passage 17 extending from one bank of the upstream river 20a to the other bank extends above the weir 2 along the weir 2. Although a part of the management passage 17 is omitted in the drawing, it is arranged along the outside of the sand removal facility 3 and extends from one bank to the other bank of the upstream river 20a.

The water control gate 5 is moved up and down by the gate elevator 6. By controlling the gate elevator 6 by the control unit 16, the water control gate 5 is arranged at a desired vertical position.

A recess 4b is formed on the bottom surface of the lead-in flow path 4 at a position in the middle of the flow path extending direction, and an upwardly protruding in-flow path weir 4a extends in the flow path width direction on the downstream side of the recess 4b. doing. The pump 9 is arranged at a position corresponding to the recess 4b. The pump 9 is moved up and down on the recess 4b by the pump elevator 11. By controlling the pump elevator 11 by the control unit 16, the suction ports 9i of the pump 9 are arranged at desired vertical positions. As the pump 9, various pumps such as a submersible pump type, a jet pump type, and a fixed pump type can be used.

The screen 12 prevents driftwood and other drifting objects D flowing in the upstream river 20a from flowing into the position of the pump 9. The screen 12 can smoothly pass the water W and the sediment S. Therefore, a mesh plate having a relatively coarse mesh, a multi-hole plate, a frame having a plurality of bars crossing the lead-in flow path 4, and the like can be used as the screen 12.

The screen 12 is moved up and down by the screen elevator 13. By controlling the screen elevator 13 with the control unit 16, the lower end surface of the screen 12 is arranged at a desired vertical position. It is desirable that the lower end surface of the screen 12 be able to rise to a position higher than the water surface at the place where the screen 12 is arranged. The screen 12 may be arranged on the upstream side of the suction port 9i of the pump 9, and a fixed type that does not move up and down can be adopted. A winch or the like is used as the gate elevator 6, the pump elevator 11, and the screen elevator 13.

The image taken by the surveillance camera 15 is displayed on a monitor installed in a monitoring room or the like at a remote location. It is also possible to take an image of the lead-in flow path 4 with the monitoring camera 15 and display it on a monitor installed in a monitoring room or the like in a remote place so that the water level of the lead-in flow path 4 can be grasped.

Next, an example of a procedure for discharging the sediment S on the bottom of the upstream river 20a to the downstream area of the dam 18 by using this discharge system 1 will be described.

In normal times when the flow rate of the water W in the upstream river 20a is not large, such as when it is not raining, the water control gate 5 is moved downward to close the lead-in flow path 4 as illustrated in FIGS. 6 and 7. As a result, the water W is prevented from passing through the lead-in flow path 4. On the other hand, as illustrated in FIG. 5, the water W on the upstream side of the weir 2 crosses the weir 2 and flows into the reservoir 19. In this embodiment, the water W passes between the upper and lower parts of the weir 2 and the management passage 17.

Since the sand flowing from the upstream cannot cross the weir 2 and is temporarily deposited on the upstream side of the weir 2, it is avoided that a large amount of sediment S is generated in the reservoir 19. In normal times, the pump 9 may be moved to a retracted position on the water, and the screen 12 may be arranged at a position straddling the water and the water.

When heavy rain or the like causes a large flow rate of water W in the upstream river 20a, as illustrated in FIG. 8, the water control gate 5 is moved upward to move the lead-in flow path 4 blocked by the water control gate 5. open. By opening the lead-in flow path 4, water W on the upstream side of the weir 2 can flow into the lead-in flow path 4. The sediment S generated on the bottom of the upstream river 20a due to the sand flowing from the upstream side can also be efficiently flowed into the lead-in flow path 4 as the water W flows into the lead-in flow path 4. The lower end surface of the screen 12 may be arranged in water so that the screen 12 does not interfere with the inflow of sediment S.

In this embodiment, since the weir 4a in the flow path and the recess 4b are formed, the inflowing sediment S is blocked from moving by the weir 4a in the flow path and easily accumulates in the recess 4b. The water W that has flowed into the lead-in flow path 4 passes through the weir 4a in the flow path and flows into the sand drainage channel 7. When the amount of water W flowing into the lead-in flow path 4 is large (when the momentum of the water W is strong) such as during a flood, the sediment S that flows together with the water W over the weir 4a in the flow path to the sand drainage channel 7. The amount of

Further, when the water W flows into the lead-in flow path 4, the water level on the upstream side of the weir 2 can be lowered below the height of the weir 2. As a result, the sediment S is prevented from flowing into the reservoir 19 over the weir 2.

Next, in the lead-in flow path 4, the pump 9 is moved downward to insert the suction port 9i into the inflowing sediment S. Then, the sediment S is sucked by the pump 9 together with a part of the water W that has flowed into the lead-in flow path 4. As illustrated in FIG. 9, the sediment S and the water W sucked from the suction port 9i are transferred to the sand drainage channel 7 through the pipeline 10. When the sediment S and the water W pass through the concentration sensor 10a, the sediment concentration is sequentially detected. Based on the concentration data detected by the concentration sensor 10a, for example, by changing the vertical position of the suction port 9i, the sediment S to be transferred to the sand removal passage 7 can be adjusted to an appropriate amount (concentration). Therefore, in this sand removal facility 3, the sediment S that has flowed into the lead-in flow path 4 is sucked into the pump 9 and passes through the pipeline 10 and the lead-in flow path 4 without passing through the pipeline 10. It is possible to transfer to the sand removal channel 7 along with the passing route.

The vertical movement of the water control gate 5 and the pump 9 can be controlled based on the water level of the lead-in flow path 4 detected by the water level sensor 14. Various data such as the water level for moving the water control gate 5 and the pump 9 upward and the amount of upward movement thereof, the water level for moving downward and the amount of downward movement thereof, and the like are input and stored in advance in the control unit 16. The control unit 16 also inputs and stores an appropriate range of the sediment concentration in the pipeline 10.

When an image of the water level of the lead-in flow path 4 is taken by the surveillance camera 15 and displayed on a monitor installed in a monitoring room or the like at a remote location, the operator looks at the image displayed on the monitor and then displays the image. It is also possible to control the water control gate 5, the pump 9, and the screen 12 by issuing a command signal to the control unit 16 by remote control. By this operation, the water control gate 5, the suction port 9i of the pump 9, and the screen 12 can be moved to desired vertical positions.

The sediment S transferred to the sand removal passage 7 by the pump 9 is put into the sand removal bypass tunnel 8. Since a part of the water W and the sediment S that have passed through the lead-in flow path 4 also flows through the sand removal passage 7, the water W and the sediment S are also put into the sand removal bypass tunnel 8. In the sand discharge bypass tunnel 8 having a slope equal to or higher than the specified gradient, the deposited sediment S and water W are transferred as muddy water and discharged to the downstream river 20b.

In this sand removal system 1, a structure is adopted in which the sediment S is sucked by the pump 9 and transferred to the sand removal passage 7 and then put into the sand removal bypass tunnel 8, so that the sand removal bypass tunnel 8 having a predetermined gradient or more is adopted. The restrictions on the site conditions for the construction will be relaxed. That is, even in the field under various conditions, it becomes easy to construct the sand removal bypass tunnel 8 having a predetermined gradient or more. In addition, the sand removal bypass tunnel 8 can be shortened.

By transferring the sediment S by the pump 9, turbid water in which the sediment S is controlled to a high content can flow through the sand discharge bypass tunnel 8. That is, when the slurry concentration of turbid water cannot be controlled, it is necessary to increase the tunnel cross-sectional area in order to secure a predetermined amount of sand discharged assuming a low concentration, but according to the present invention, it is more than that. The tunnel cross-sectional area can also be reduced. Therefore, by using this discharge system 1, it is advantageous to reduce the cost required for the construction of the sand removal bypass tunnel 8.

Further, the sediment S is transferred by the pump 9, and the sediment S is transferred by the water W flowing in this order through the sand removal facility 3, the sand removal passage 7, and the sand removal bypass tunnel 8 (using the head difference). This is also advantageous in reducing the running cost required for operating the equipment.

The amount of sediment S on the upstream side of the weir 2 increases as the flow rate of water W on the upstream side of the weir 2 increases. In this sand discharge system 1, the sediment S can be discharged to the downstream area of the dam 18 at the timing when the amount of the sediment S increases. Therefore, it is advantageous to avoid the sediment S from being accumulated for a long period of time as compared with the case where the sediment S is not dealt with. That is, it is possible to prevent the sediment S, which has been accumulated for a long period of time and sludge, from being discharged to the downstream river 20b. The sediment S discharged to the downstream area contributes to the prevention of riverbed deterioration of the downstream river 20b and the formation of the coastline near the river mouth.

As illustrated in FIG. 10, the driftwood D such as driftwood is blocked by the screen 12 to prevent the inflow into the lead-in flow path 4 on the upstream side of the pump 9. As a result, it is possible to prevent the suction port 9i of the pump 9 from being blocked by the drifting object D and being damaged by the drifting object D, so that the sediment S can be stably sucked and transferred. A large amount of drifting material D may be captured on the screen 12. Since the image taken by the surveillance camera 15 is displayed on the monitor, the state of the drifting object D captured on the screen 12 can be confirmed by the operator by looking at the monitor and can be removed if necessary.

If necessary, the operator issues a command signal to the control unit 16 by remote control to control the vertical position of the screen 12 to a desired position. In this case, as illustrated in FIG. 11, the screen 12 is moved upward so that the lower end surface of the screen 12 is arranged at a position slightly higher than the water surface. As a result, the floating drifting object D passes between the water surface and the lower end surface of the screen 12, passes through the lead-in flow path 4, and is transferred to the sand removal passage 7. The pump 9 is moved to a retracted position on the water in advance. By this operation, the drifting object D is removed from the screen 12, so that stable suction of the sediment S by the pump 9 can be ensured.

As illustrated in FIGS. 12 and 13, a plurality of pumps 9 (9A, 9B, 9C) can be arranged. The pumps 9A, 9B, and 9C are fixed at predetermined positions above the lead-in flow path 4, and the suction ports 9i are arranged at intervals in the extending direction of the lead-in flow path 4. , The vertical position is set to be different. The number of pumps 9 can be appropriately increased, and one pump 9 is connected to a plurality of suction ports 9i arranged at intervals in the extending direction of the lead-in flow path 4 and having different vertical positions. Can also be.

In this embodiment, the suction port 9i of the pump 9A on the most upstream side is set to the highest position, and the suction port 9i of the adjacent pumps 9B on the downstream side is set to the lowest position. Specifically, the suction port 9i of the pump 9A is set at a shallow water depth, and the suction port 9i of the pump 9B is set so as to enter the recess 4b on the bottom surface of the suction flow path 4. The vertical position of the suction port 9i of the pump 9C on the most downstream side is set at a position between the suction port 9i of the pump 9A and the suction port 9i of the pump 9B, and is near the bottom surface on the downstream side other than the recess 4b of the suction flow path 4. Is set to.

The pipe line 10 connected to the discharge port 9e of each of the pumps 9A, 9B, 9C extends to the sand removal line 7. A concentration sensor 10a is attached in the middle of the pipeline 10.

When the arrangement form of the pump 9 is adopted, as illustrated in FIGS. 14 and 15, the pump 9B arranged at the position corresponding to the recess 4b is mainly used to collect the sediment flowing into the lead-in flow path 4. Aspirate sand S. The procedure for flowing the sediment S into the lead-in flow path 4 is the same as that in the previous embodiment. The sediment S and water W sucked by the pump 9B are transferred to the sand removal passage 7 through the pipeline 10 and then put into the sand removal bypass tunnel 8.

The most downstream pump 9C is operated based on the concentration data sequentially detected by, for example, the concentration sensor 10a. Then, the sediment S and the water W sucked by the pump 9C are used to adjust the content of the sediment S in the muddy water in the sand drainage passage 7 (sand drainage bypass tunnel 8). Alternatively, the pump 9C is used for recovery when the pump 9B is buried in the sediment S and the sediment S cannot be sufficiently sucked.

When the lead-in flow path 4 is closed by the water control gate 5, the pump 9A on the most upstream side sucks the relatively less turbid water W at the shallow water depth of the lead-in flow path 4. These can be washed by flowing this water W through the pipe line 10 to the sand removal passage 7 and the sand removal bypass tunnel 8.

The sand removal facility 3 illustrated in FIG. 3 is installed at one end of the weir 2 in the extending direction, but is not limited to this. Further, the extending direction of the weir 2 is not limited to the direction illustrated in FIG. 3 (the direction orthogonal to the flow of water W in the upstream river 20a). As illustrated in FIGS. 16 and 17, the sand removal facility 3 may be installed at a position protruding to the most downstream side of the weir 2 in a plan view. When the sand removal facility 3 is arranged in this way, the water W on the upstream side flows toward the sand removal facility 3, so that the sediment S can easily flow into the lead-in flow path 4.

1 Discharge system 2 Weir 3 Sand removal facility 4 Intake flow path 4a Weir in the flow path 4b Recess 5 Water control gate 6 Gate lift 7 Sand removal path 8 Sand removal bypass tunnel 8a Inlet 8b Outlet 9 (9A, 9B, 9C) Pump 9i Suction port 9e Discharge port 10 Pipeline 10a Concentration sensor 11 Pump lift 12 Screen 13 Screen lift 14 Water level sensor 15 Surveillance camera 16 Control unit 17 Management passage 18 Dam 19 Reservoir 20a Upstream river 20b Downstream river W Water S Sediment D Drifting (Dam, etc.)

Claims (6)

A weir installed in the upstream area of the dam, a sand removal facility installed at a predetermined position in the extending direction of this weir, a sand removal channel extending downstream from this sand removal facility, and this sand removal channel. A sand discharge system having a sand discharge bypass tunnel having a slope or higher that connects to the downstream area of the dam.
The sand removal facility has a lead-in flow path connected to the sand drainage channel, a water control gate for opening and closing the lead-in flow path, and a pump arranged on the upstream side of the water control gate in the lead-in flow path. A pipeline extending between the discharge port of the pump and the sand drainage channel, the water control gate, and a control unit for controlling the pump are provided.
By closing the lead-in flow path by the water control gate, water on the upstream side of the weir crosses the weir and flows into the reservoir between the weir and the dam.
By opening the lead-in flow path by the water control gate, water on the upstream side of the weir flows into the lead-in flow path together with the sediment generated by the sand flowing from the upstream side. The water level on the upstream side of the weir is lower than the height of the weir, and the sediment that has flowed into the lead-in flow path is sucked by the pump and passes through the conduit and the lead-in flow path. The sediment transferred to the sand drainage channel and the water on the upstream side are discharged to the downstream area of the dam through the sand drainage bypass tunnel by enabling the transfer to the sand drainage channel. A sediment discharge system characterized by the configuration. The sediment discharge system according to claim 1, further comprising a pump elevator that changes the vertical position of the suction port of the pump. According to claim 1 or 2, a plurality of the pumps are provided, the suction ports of the respective pumps are arranged at intervals in the extending direction of the lead-in flow path, and the vertical positions are arranged differently. The described sediment discharge system. A screen having water permeability and sand permeability arranged on the upstream side of the pump in the lead-in flow path and a screen elevator for changing the vertical position of the screen are provided, and the lower end surface of the screen is pressed by the control unit. The sediment discharge system according to any one of claims 1 to 3, which is configured to be able to rise above the water surface at the place where the screen is arranged. The sedimentation according to any one of claims 1 to 4, wherein the predetermined position in the extending direction of the weir in which the sand removal facility is installed is a position protruding to the most downstream side of the weir in a plan view. Emission system. A sand removal facility is installed at a predetermined position in the extending direction of the weir installed in the upstream area of the dam, and a sand removal channel is extended downstream from this sand removal facility, and the sand removal path is above the specified slope. A lead-in flow path connected to the downstream area of the dam via a sand drainage bypass tunnel and the sand drainage facility is connected to the sand drainage channel, a water control gate for opening and closing the lead-in flow path, and this lead-in flow path. In the configuration equipped with a pump arranged on the upstream side of the water control gate,
By closing the lead-in flow path by the water control gate, water on the upstream side of the weir is allowed to flow over the weir and flow into the reservoir between the weir and the dam.
By opening the lead-in flow path by the water control gate, water on the upstream side of the weir is allowed to flow into the lead-in flow path together with sand generated by sand flowing from the upstream side, and the weir A route in which the water level on the upstream side is lowered below the height of the weir, and the sediment that has flowed into the lead-in flow path is sucked by the pump to pass through the pipeline and a route through the lead-in flow path. The feature is that the sediment transferred to the sand drainage channel and the water on the upstream side are discharged to the downstream area of the dam through the sand drainage bypass tunnel. How to discharge the sediment.

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