JP7089137B2 - Dam deposit downstream reduction method and system - Google Patents

Description

The present invention relates to a dam deposit downstream reduction method and system for supplying dam sediments to the downstream of the dam.

The reservoir capacity of the dam's reservoir will decrease with the passage of time from the start of service due to the accumulation of sediment that has flowed in from the upstream. In addition, the riverbed in the upper reaches of the dam has risen, causing various adverse effects such as increased flood risk, lowering of the riverbed and retreat of the coastline in the lower reaches. As a countermeasure, in recent years, based on the concept of "comprehensive sediment management" of quicksand system, sediments such as sediment of the dam have been removed and discharged downstream of the dam (hereinafter, also referred to as "supply"). ing.

Japanese Patent Application Laid-Open No. 2002-294677 Japanese Unexamined Patent Publication No. 2001-164543 Japanese Unexamined Patent Publication No. 10-118697 Japanese Unexamined Patent Publication No. 2001-20318

In the above-mentioned comprehensive sediment management, the most common method at present is to dredge a reservoir, transport the dredged soil to the downstream of the dam by a dump truck, temporarily store it, and supply it to the downstream of the dam in the event of a flood. However, in the case of this soil placement method, if dredged soil containing excessive silt or clay is supplied as it is, it causes long-term turbidity of the river, which is not desirable in terms of the river environment. Only materials can be used as silt materials.

In addition, if the dredged soil is flushed (flushed with running water) while the dam discharge rate during floods is small, silt clay may remain in the river and adversely affect fish and the like.

The conditions for installing a dam (Unazuki Dam / Dashidaira Dam) where a sand removal gate is installed in the dam are large for power generation and water utilization if it takes time to restore the water storage level of the dam when the water level drops due to sand removal. In order to have an impact, it is required that the river flow is sufficiently large with respect to the water storage capacity.

Patent Documents 1 and 2 propose a method for flowing and discharging underwater deposits using hydrostatic pressure. However, these suction methods and sand removal bypass require large-scale construction such as remodeling of bypass tunnels and dams. Further, Patent Document 3 proposes that the slurry-like mixture is separated into silt clay and organic matter in order to prevent long-term turbidity of the dam, and the silt clay is returned to the bottom of the dam to decompose the organic matter. This method is costly for dehydration and decomposition treatments.

In Patent Document 4, the mud from the bottom mud dredged from the reservoir is classified into gravel and silt clay, and the gravel is returned to the downstream river. The silt clay is dehydrated and then retreated as dehydrated sludge. Propose a method. However, the treatment of silt clay is not aimed at downstream supply.

In view of the above-mentioned problems of the prior art, the present invention is a method for reducing the downstream of dam sediments, which does not adversely affect the downstream rivers even if the silt clay contained in the sediments of the reservoir of the dam is supplied downstream of the dam. And the purpose is to provide the system.

The downstream reduction method of dam deposits for achieving the above objectives is a downstream reduction method of dam deposits in which the sediments of the reservoir of the dam are supplied to the downstream of the dam, and the sediments drenched from the reservoir in normal times are predetermined grains. The silt clay content below the diameter is classified into sand exceeding the predetermined particle size, the classified silt clay content is sent to the wastewater storage section, and the silt clay content is stored and settled in the wastewater storage section. During a flood, water is supplied from the reservoir to the wastewater storage section, the settled silt clay is stirred to form muddy water, and the muddy water is supplied downstream of the dam based on the discharge rate of the dam (m ³ / sec). The supply amount of the muddy water (m ³ / sec) is determined based on the discharge amount, the turbidity of the muddy water, and the allowable turbidity downstream of the dam .

According to this downstream reduction method of dam sediments, the reservoir of the dam is drenched in normal times, the drowned sediments are classified into silt clay and sand, and the classified silt clay is stored in the wastewater reservoir. When a flood occurs, water is supplied to the wastewater reservoir and the settled silt clay is stirred to make muddy water, and then the muddy water is discharged downstream of the dam based on the discharge rate (m ³ / sec) of the dam. It is possible to supply muddy water to the downstream of the dam when the discharge rate is sufficient so that the silt clay content does not remain in the downstream river. Therefore, even if silt clay in the sediment of the reservoir is supplied to the downstream of the dam, there is no adverse effect on the river.

In the method for reducing downstream of dam deposits, it is preferable to use the classified sand as soil downstream of the dam. As a result, the sand generated by the classification of the sediment can be supplied and reduced downstream, and since it does not contain silt clay, there is no risk of turbid water in the river. The sand can also be effectively used as an aggregate.

Further, it is preferable to discharge the residual water of the supernatant in the waste mud storage portion, treat it with turbid water, and then return it to the reservoir.

Further, it is preferable to start the supply of the muddy water when the discharge flow rate becomes equal to or higher than a preset predetermined value.

Further, it is preferable to increase the supply amount of the muddy water (m ³ / sec) according to the increase of the discharge flow rate and stop the supply of the muddy water according to the convergence of the discharge flow rate.

Further, the amount of the muddy water supplied (m ³ / sec) is determined based on the discharge amount, the turbidity of the muddy water, and the allowable turbidity downstream of the dam, and thus the silt clay content. Even if the muddy water containing silt is supplied downstream, the downstream river does not exceed the allowable turbidity.

The dam sediment downstream reduction system for achieving the above object is a dam sediment downstream reduction system that supplies the sediment of the dam reservoir to the downstream of the dam, and the sediment dredged from the reservoir is reduced to a predetermined particle size or less. The silt clay content of the above, a classification device for classifying into sand exceeding the predetermined particle size, a silt storage unit for storing and precipitating the classified silt clay content, and a silt clay content settled in the mud storage unit. It is equipped with a stirring device for stirring the silt, a pump for supplying water from the reservoir to the silt storage section, and a first turbidity meter for measuring the turbidity of the mud water in the mud storage section. Water is supplied by the pump in the reservoir, and the silt clay content is agitated by the stirrer to form muddy water, and the muddy water is supplied downstream of the dam based on the discharge rate (m ³ / sec) of the dam. The muddy water supply amount (m ³ / sec) is controlled based on the discharge rate, the turbidity measured by the first turbidity meter, and the allowable turbidity downstream of the dam. Will be done .

According to this dam sediment downstream reduction system, sediments drenched from the dam's reservoir are classified into silt clay and sand by a classifier, and the classified silt clay is stored in the wastewater reservoir. When a flood occurs, water is supplied from the reservoir to the wastewater reservoir by pumping, and the settled silt clay is stirred with a stirrer to make muddy water, and then the muddy water is discharged from the dam (m ³ / sec). ), So that muddy water can be supplied downstream of the dam when the discharge is sufficient so that silt clay does not remain in the river downstream of the dam. Therefore, even if silt clay in the sediment of the reservoir is supplied to the downstream of the dam, there is no adverse effect on the river.

In the dam sediment downstream reduction system, the muddy water supply amount (m ³ / sec) is the discharge rate, the turbidity measured by the first turbidity meter, and the allowable turbidity downstream of the dam. By being controlled based on the above, even if muddy water containing silt clay is supplied downstream, the allowable turbidity is not exceeded in the downstream river.

Further, a water supply control valve that controls the amount of water supplied from the reservoir, a drainage control valve that controls the amount of drainage when the muddy water stirred in the wastewater storage unit is discharged, and a flow rate of the discharged muddy water are measured. It is preferable to further include a flow meter, increase or decrease the supply amount of the muddy water by the water supply control valve, and finely adjust the supply amount of the muddy water by the drainage control valve based on the measurement result by the flow meter. ..

Further, it is preferable to further include a turbid water treatment device for treating the residual water of the supernatant in the waste mud storage portion.

The stirring device includes a stirring portion supported by a support shaft extending in the vertical direction and a rotating portion, and the rotation of the rotating portion causes the wastewater storage portion and the stirring portion to be relatively rotated. It is preferable that the stirring portion is configured to stir the silt clay content of the waste waste storage portion. In addition, it is preferable to configure the support shaft to move downward together with the stirring portion with the relative rotation of the waste mud storage portion and the stirring portion.

Further, the stirring device rotates around a moving portion that can move horizontally in the mud storage section, an arm extending from the moving section, and a rotation axis provided at the tip of the arm and extending in a substantially horizontal direction. A unit may be provided, and the stirring unit may be rotated by the movement of the moving unit to agitate the silt clay content of the mud storage unit.

Further, a turbidity meter for measuring the turbidity of the discharged muddy water is further provided, and the increase / decrease in the turbidity of the muddy water is measured by the turbidity meter of the rotating portion or the moving portion of the stirring device. It is preferable to carry out by control.

Further, it is preferable that the pump and the stirring device are automatically operated based on the determination of the occurrence of the flood so that the supply amount of the muddy water is automatically controlled. As a result, the dam deposit downstream reduction system can be automatically operated and controlled, and unmanned automatic operation becomes possible. The judgment of flood occurrence is made by the dam manager based on the precipitation data in the upstream area of the dam and the water level of the dam, but it is automatically pumped based on various information such as the precipitation data and the water level of the dam. It may be configured to operate with the stirrer.

According to the dam deposit downstream reduction method and system of the present invention, even if the silt clay contained in the sediment of the dam reservoir is supplied to the downstream of the dam, it does not adversely affect the downstream river.

FIG. 1 is a diagram schematically showing a dam deposit downstream reduction system according to the present embodiment and dams and the like around the dam. It is a flowchart for demonstrating the process in normal times of the dam sediment downstream reduction method by this embodiment. It is a flowchart for demonstrating the main process at the time of flood of the dam sediment downstream reduction method by this embodiment. In this embodiment, it is a graph which shows the relationship between the discharge flow rate and time in order to explain the timing of supplying muddy water downstream of a dam and stopping it. FIG. 3 is a perspective view schematically showing the configuration of the mud drainage tank, the agitator, and the surroundings thereof in FIG. 1. It is a top view which shows the stirring part in the mud drain tank of FIG. It is the figure which cut in the direction of VII-VII line of FIG. It is a block diagram which shows schematic the control system of the dam sediment downstream reduction system by this embodiment. It is a flowchart for demonstrating each process of the turbidity measurement of the mud water before the supply to the downstream of a dam in the mud drain tank of FIG. 1 and FIG. It is a flowchart for demonstrating each process of supply amount adjustment and turbidity adjustment after the dam downstream supply of muddy water. It is a perspective view which shows another stirring apparatus by this embodiment.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a diagram schematically showing a dam deposit downstream reduction system according to the present embodiment and dams and the like around the dam.

As shown in FIG. 1, the dam sediment downstream reduction system 10 according to the present embodiment is installed near the reservoir 2 of the dam 1, and after the sediment 3 such as earth and sand that has flowed into and accumulated in the reservoir 2 from the upstream 4 is drowned. , The classification device 11 that classifies the drowned sediment into silt clay content with a particle size of 0.075 mm or less and sand with a particle size of more than 0.075 mm, and the silt clay content sent from the classification device 11 by pipeline pumping. A mud drainage tank 12 having a stirring device that stores and settles and stirs the silt clay content that has settled during a flood, a muddy water treatment device 13 that treats the residual water of the supernatant of the mud drainage tank 12 with muddy water and returns it to the reservoir 2, and a muddy water treatment device 13 during a flood. A submersible pump 14 for supplying water to the mud drain tank 12 is provided. At the time of flood, the silt clay content settled in the mud drain tank 12 is agitated to make muddy water with the supplied water, and this muddy water is discharged to the downstream 5 of the dam 1 and supplied.

As the classifying device 11, various known classifying machines / classifying devices can be used, and for example, a spiral classifying machine, a drag classifying machine, a rotary classifying machine, a hydraulic classifying machine, a sizer, a wet cyclone and the like can be used.

Further, the turbid water treatment device 13 can use various known turbid water treatment devices and turbid water treatment plants, and has, for example, various treatment functions such as precipitation separation, neutralization, and wastewater of suspensions, and has low turbidity. A turbid water treatment device or the like that discharges water can be used.

Next, the method of reducing the dam deposit downstream by the dam deposit downstream reduction system 10 of FIG. 1 will be described with reference to FIGS. 1 to 4. FIG. 2 is a flowchart for explaining a process in normal times of the dam deposit downstream reduction method according to the present embodiment. FIG. 3 is a flowchart for explaining the main steps of the dam deposit downstream reduction method according to the present embodiment at the time of flooding. FIG. 4 is a graph schematically showing the relationship between the discharge rate of the dam and the time in order to explain the timing of supplying and stopping the muddy water downstream of the dam in the present embodiment.

First, in normal times, as shown in FIGS. 1 and 2, the sediment 3 such as earth and sand deposited in the reservoir 2 is dredged by a dredging ship or the like (S01), and the dredged sediment is classified by the classifying device 11 (S02). ), The classified sand (S03) having a particle size of more than 0.075 mm and the silt clay content (S04) having a particle size of 0.075 mm or less are treated as follows.

That is, sand having a particle size of more than 0.075 mm is provisionally placed in the temporary storage site 18 (S05), and then transported by a dump truck or the like in a timely manner to be used as soil downstream of the dam (S06). It is effectively used as (S07).

Further, the silt clay content having a particle size of 0.075 mm or less is sent from the classification device 11 to the mud drain tank 12 by pipeline pressure feeding (S08). The silt clay content is stored and settled in the mud drain tank 12 (S09), and residual water in the supernatant is generated (S10). The residual water in the mud drain tank 12 is sent to the turbid water treatment device 13 for turbid water treatment (S11), and the treated water having low turbidity is returned to the reservoir 2 (S12).

The above steps S01 to S12 are normally executed in the dam deposit downstream reduction system 10.

Next, at the time of flood, as shown in FIGS. 1 and 3, when it is determined that a flood has occurred (S21), water is started to be supplied from the reservoir 2 to the mud drain tank 12 by the submersible pump 14 (S22), and the mud is drained. The silt clay content settled in the tank 12 is stirred by a stirrer (S23) to prepare muddy water (S24). In the water supply step S22, it is preferable to take water from the surface of the dam lake (turbidity of about 50 PPM or less) and supply it to the mud drain tank 12.

The flood occurrence determination step S21 is usually performed by the dam manager based on various flood information such as the amount of precipitation in the upstream area of the dam and the water level of the reservoir of the dam. The signal may be determined by being received by the control device 41 (FIG. 8) of the control system. Further, the control device 41 (FIG. 8) may be configured to automatically determine based on the flood information.

Further, in FIG. 3, the water supply step S22 and the stirring step S23 for preparing muddy water are started after the flood occurrence determination step S21, but usually there is a certain amount of time from the time of the flood occurrence determination to the start of the dam discharge. Therefore, muddy water can be produced in the meantime. Further, as shown in FIG. 4, since there is a certain amount of time from the start of the dam discharge to the downstream supply of muddy water (T1), the water supply step S22 and the stirring step S23 may be started after the dam discharge start is confirmed. good.

After the flood occurrence is determined, the discharge is started from the regular spillway of the dam 1 (S25), and when the water level of the dam downstream 5 rises, the dam downstream soil 19 made of sand is supplied to the dam downstream 5 (S26). When the discharge from the dam 1 is completed and the water level of the dam downstream 5 is lowered to the original level, the supply of the dam downstream soil 19 to the dam downstream 5 is terminated.

Further, as shown in FIG. 4, when the discharge rate Q (m ³ / sec) per unit time from the dam 1 increases with time and becomes equal to or more than the first predetermined amount Q1 preset in the time T1 (S27). Mud water is discharged from the mud drain tank 12 and supplied to the downstream of the dam 5 (S28). The first predetermined amount Q1 is set to a sufficient discharge flow rate so that silt clay content does not remain in the river downstream of the dam.

At the time of flood, the discharge Q (m ³ / sec) per unit time from the dam 1 increases with time, reaches the peak discharge (S29), and then decreases with time, as shown in FIG. When the amount becomes equal to or less than the second predetermined amount Q2 preset in T2 (S30), the supply of muddy water to the downstream of the dam 5 is stopped (S31).

According to the downstream reduction method of dam deposits of the present embodiment, the sediments drenched from the reservoir of the dam in normal times are classified into silt clay and sand by the classification device 11, and the classified silt clay is classified into a mud drain tank. It is stored and settled in No. 12, and when a flood occurs, water is supplied from the reservoir 2 to the mud drain tank 12 by a submersible pump 14, the settled silt clay is stirred to make muddy water, and then the muddy water is discharged to the dam 1. When (m ³ / sec) reaches a sufficient discharge rate (first predetermined amount Q1 in FIG. 4) so that silt clay does not remain in the river downstream of the dam, it is supplied downstream of the dam. Therefore, muddy water can be supplied to the downstream of the dam at an appropriate supply time, and even if muddy water containing silt clay is supplied to the downstream of the dam, it does not adversely affect the river.

In the conventional general soil placement method, the earth and sand are placed directly in the river channel downstream of the dam, so if the flood is small, the soil placement material will not flow completely and silt clay will remain in the river channel, resulting in a river environment. Could have an adverse effect on. On the other hand, according to the present embodiment, when a flood of a certain scale or more occurs, that is, the discharge rate Q (m ³ / sec) per unit time of the dam 1 becomes the first predetermined amount Q1 or more. At that time, by supplying muddy water containing silt clay to the downstream of the dam, silt clay does not remain in the river channel downstream of the dam.

Further, when the discharge Q of FIG. 4 becomes the first predetermined amount Q1 or more, the downstream supply of muddy water is started, and the supply amount of muddy water is increased according to the increase of the discharge rate of the dam to reach the peak discharge rate. By stopping the supply of muddy water at the second predetermined amount Q2 or less in accordance with the subsequent convergence of the flood, it is possible to efficiently supply the muddy water downstream of the dam without adversely affecting the river environment.

Further, as shown in FIG. 4, the downstream supply of muddy water is started at the time T1 and the discharge rate Q1 of the dam, and the downstream supply of the muddy water is stopped at the time T2 and the discharge rate Q2 of the dam. By setting the discharge rate Q2 of the dam when the supply of muddy water is stopped to a high value, the muddy water will flow completely after the supply of muddy water is stopped, and silt clay will not remain in the river channel 5 downstream of the dam, and the inside of the river will be sufficiently cleaned. Can be returned to the normal state.

Moreover, even if the sediment is originally unsuitable for river reduction due to the large amount of silt clay, it can be improved into a material suitable for river reduction by classifying the sediment after dredging. As a result, it becomes possible to take measures against the riverbed lowering and realize a desirable habitat for fish.

In addition, based on the earth-laying method, which has the most achievements and the lowest initial cost, silt clay is supplied as muddy water from the mud drain tank, and the downstream reduction method and system of dam deposits considering the river environment at the time of flood. Can be provided. Since the suction method of Patent Documents 1 and 2 and the large-scale construction such as the sand removal bypass tunnel are not required, the initial cost is low.

In addition, compared with the general dredging method and the earth-placement method, a dumping ground is not required, and only sand can be transported, and the transportation cost is reduced, so that the running cost is low.

Next, the configuration of the mud drainage tank, the agitator, and the surroundings of the dam sediment downstream reduction system of FIG. 1 will be described with reference to FIGS. 5 to 7. FIG. 5 is a perspective view schematically showing the configuration of the mud drainage tank, the agitator, and the surroundings thereof of FIG. FIG. 6 is a plan view showing the stirring portion in the mud drain tank of FIG. FIG. 7 is a view cut in the direction of the line VII-VII of FIG.

As shown in FIG. 5, the mud drainage tank 12 is configured to have a cylindrical shape, and is configured so that silt clay content can be settled and stored inside, and has a stirring device 20 for stirring the settled silt clay content. The mud drainage tank 12 is installed on the ground so as to be rotatable, but the installation structure thereof is not shown in FIG. Further, a plurality of mud drainage tanks 12 having the stirring device 20 may be installed.

The stirring device 20 stirs the stirring portion 21 extending horizontally in the mud drain tank 12, the support shaft 22 located at the center of the mud drain tank 12 and extending vertically to support the stirring portion 21, and the support shaft 22. A vertical moving device 23 that moves up and down in the vertical direction together with the section 21, and a horizontal rotating device 24 that rotates the mud drain tank 12 with respect to the stirring section 21 and the support shaft 22 in order to stir the silt clay content 6 in the mud drain tank 12. And.

As shown in FIGS. 5 to 7, the stirring unit 21 has a plurality of stirring rods 21a to 21h extending radially from the central support shaft 22 in the radial direction of the mud drain tank 12. The plurality of stirring rods 21a to 21h are arranged at equal intervals in the circumferential direction, and are inclined downward from the lower end of each stirring rod 21a to 21h to stir by scraping the silt clay content 6 in the mud drain tank 12. The soil discharge plates 26a to 26h and a jet nozzle 27 for ejecting jet water JW from the water supply pipe 27a toward the silt clay content 6 along the soil discharge plates 26a to 26h.

As shown in FIG. 6, the soil removal plates 26a to 26h have a shorter horizontal length than the horizontal lengths of the stirring rods 21a to 21h, and their radial positions are different from those of the adjacent soil removal plates. The soil removal plates 26a to 26h as a whole are configured to be evenly located from the support shaft 22 to the outer periphery in the radial direction. When the mud drain tank 12 rotates in the rotation direction R, as shown in FIGS. It can be scraped off from the surface little by little and stirred. Further, even the silt clay content solidified by the jet of jet water JW from the jet nozzle 27 can be sufficiently demudged.

As shown in FIG. 5, the vertical moving device 23 is arranged in the horizontal portion 25 above the mud drain tank 12, has a known electric spindle structure, and is screwed with the threaded portion 22a of the support shaft 22 to rotate. It is converted into a linear movement of the support shaft 22. As a result, the stirring unit 21 can be moved to the lower part of FIG. 7 together with the support shaft 22 in accordance with the progress of stirring the silt clay content, and the silt clay content 6 in the mud drain tank 12 can be stirred from the upper part to the lower part. The horizontal portion 25 is supported by the supports 25a to 25d.

As shown in FIG. 5, the horizontal rotary device 24 includes an outer peripheral gear 24a arranged around the outer periphery of the mud drain tank 12, a rotary gear 24b screwed with the outer peripheral gear 24a, and an electric motor 29 for rotating the rotary gear 24b. , Have. When the rotary gear 24b is rotated by the rotation of the electric motor 29, the mud drain tank 12 rotates together with the outer peripheral gear 24a.

The amount of stirring of the silt clay content 6 by the stirring unit 21 accompanying the rotation of the mud drain tank 12 can be adjusted by the rotation speed of the electric motor 29 and the downward moving speed of the stirring unit 21 by the vertical moving device 23.

As shown in FIG. 5, the dam sediment downstream reduction system 10 has a pipe 31 extending from the classification device 11 of FIG. 1 to the mud drainage tank 12, and the silt clay component classified by the classification device 11 through the pipe 31 is pumped. It is sent to the mud drain tank 12.

Further, it has a pipe 32 extending from the upper part of the mud drain tank 12 of FIG. 5 to the muddy water treatment device 13 of FIG. 1 and a pump 33, and the residual water of the supernatant in the mud tank 12 is piped by the operation of the pump 33. It is sent to the turbid water treatment device 13 through 32.

Further, it has a pipe 34 extending from the submersible pump 14 of the reservoir 2 of FIG. 1 to the mud drain tank 12, and water is supplied from the reservoir 2 to the mud tank 12 through the pipe 34 by the operation of the submersible pump 14. Such water supply is controlled by a water supply control valve 35 provided in the middle of the pipe 34.

Further, it has a muddy water supply pipe 36 extending from the upper part of the mud drainage tank 12 of FIG. 5 to the dam downstream 5 of FIG. By the operation of the pump 37, it is supplied to the downstream of the dam 5 through the muddy water supply pipe 36. The supply of the muddy water to the downstream side 5 of the dam is controlled by a muddy water control valve 38 provided in the middle of the muddy water supply pipe 36.

The water supply control valve 35 and the muddy water control valve 38 can use known control valves, control valves, control valves, etc., and have a control mechanism for controlling the flow rate of water and a drive unit for driving the control mechanism. , The drive unit is controlled by the control signal, and the flow rate of water is controlled by the control mechanism.

Further, as shown in FIG. 5, a first turbidity meter 28 for measuring the turbidity of the muddy water in the mud drain tank 12 is arranged in the mud drain tank 12. Further, in the muddy water supply pipe 36 of FIG. 5, a second turbidity meter 39 for measuring the turbidity of the muddy water supplied to the downstream of the dam is arranged on the upstream side of the muddy water control valve 38, and the muddy water control valve 38 is also arranged. A flow meter 40 for measuring the flow rate of muddy water is arranged on the downstream side of the.

Next, a control system for automatically controlling the dam deposit downstream reduction system 10 of FIGS. 1 and 5 to 7 will be described with reference to FIG. FIG. 8 is a block diagram schematically showing a control system of the dam deposit downstream reduction system 10 according to the present embodiment.

As shown in FIG. 8, the control system includes a control device 41 for inputting various information and measurement information and sending a control signal to each unit. The control device 41 is, for example, a memory composed of a personal computer (PC), a CPU (central processing unit) that executes various controls, and a RAM that temporarily holds programs and various information for control. A storage device including a hard disk, etc., and a program for executing each step of the dam deposit downstream reduction method according to the present embodiment are installed in the storage device, and based on the program and various input information. Each step of the dam deposit downstream reduction method is automatically executed.

As shown in FIG. 8, the control device 41 has the measured turbidity information of the muddy water in the mud drain tank 12 of FIG. 5 measured by the first turbidity meter 28, and measured by the second turbidity meter 39. The measured turbidity information of the muddy water flowing through the muddy water supply pipe 36 of FIG. 5 and the measured flow rate information of the muddy water flowing through the muddy water supply pipe 36 of FIG. 5 measured by the flow meter 40 are input. In addition, permissible turbidity information, flood information and dam discharge information in rivers downstream of the dam are input.

Further, the control device 41 includes a submersible pump 14 arranged in the reservoir 2 of FIG. 1, an electric motor 29 of the stirring device 20 of FIG. 5, a vertical moving device 23, a water supply control valve 35, a muddy water pump 37, and a muddy water control valve 38. Is controlled based on each input information.

Next, each step of downstream reduction by the dam deposit downstream reduction system 10 of FIGS. 1 and 5 to FIG. 8 will be described with reference to FIGS. 9 and 10. FIG. 9 is a flowchart for explaining each process of measuring the turbidity of the mud water before the supply of the mud downstream in the mud drain tank of FIGS. 1 and 5 and determining the amount of the mud water supplied to the downstream of the dam. FIG. 10 is a flowchart for explaining each process of supply amount adjustment and turbidity adjustment after the downstream supply of muddy water to the dam.

Steps S21 to S24 in FIG. 9 are the same steps as in FIG. 3, but in the flood occurrence determination step S21 in FIG. 9, various flood information such as the amount of precipitation in the upstream area of the dam and the water level of the reservoir of the dam is shown in FIG. It is input to the control device 41 of the above, and the control device 41 of FIG. 8 automatically determines the occurrence of a flood based on these flood information.

Next, when it is determined that a flood has occurred, the control device 41 operates the submersible pump 14, opens the water supply control valve 35, and supplies water from the reservoir 2 to the mud drain tank 12 through the pipe 34 (S22).

Further, the control device 41 operates the electric motor 29 of the stirring device 20 to rotate the mud draining tank 12 with respect to the stirring unit 21, so that the soil draining plates 26a to 26h of the stirring rods 21a to 21h are shown in FIG. In this way, the silt clay content 6 in the mud drain tank 12 is scraped off to stir (S23). At this time, the jet nozzle 27 ejects the jet water JW to improve the stirring efficiency. Further, the vertical moving device 23 is operated in accordance with the stirring by the stirring unit 21 to move the stirring unit 21 downward.

Muddy water is prepared in the mud drainage tank 12 by the water supply step S22 and the stirring step S23 described above (S24), and the turbidity of the muddy water is measured by the first turbidity meter 28 in the mud drainage tank 12 (S35). ..

When adjusting the turbidity of the mud in the mud tank 12 based on the turbidity measurement result (S36), the rotation speed of the mud tank 12 by the electric motor 29 of the stirring device 20 and the stirring unit 21 by the vertical moving device 23. The turbidity of the muddy water can be adjusted by controlling the downward movement speed of the mud by the control device 41.

Next, the control device 41 inputs the measured turbidity information of the muddy water in the mud drain tank 12 by the first turbidity meter 28, the allowable turbidity information in the river downstream of the dam, and the discharge flow rate of the dam ( Based on the m ³ / sec) information, the amount of muddy water supplied to the downstream of the dam (m ³ / sec) is determined (S37). The permissible turbidity is determined for each river in consideration of the influence on the inhabiting fish and plants.

As described above, the amount of muddy water supplied to the downstream of the dam per unit time can be automatically determined by the control device 41 based on each input information. As a result, muddy water containing silt clay at an appropriate concentration can be prepared, and even if it is supplied downstream of the dam, the allowable turbidity will not be exceeded in the downstream river, and no adverse effect on the river will occur.

Next, the adjustment of the supply amount of muddy water and the adjustment of turbidity after the supply of muddy water to the downstream of the dam will be described with reference to FIG.

It is determined whether or not the dam discharge Q is within the predetermined range (S40), and if it is within the predetermined range (Q1 <Q or Q> Q2 (see FIG. 4)), it is determined as described above. Muddy water is supplied from the muddy drain tank 12 to the downstream of the dam 5 through the muddy water supply pipe 36 by operating the muddy water pump 37 (S28 (FIG. 3)). At this time, the control device 41 controls the muddy water control valve 38 to adjust the flow rate of muddy water so that the supply amount of muddy water to the downstream of the dam becomes the determined supply amount.

The determination step S40 and the muddy water supply step S28 correspond to the steps S27 to S30 of FIG. 3, and when the dam discharge rate Q becomes a predetermined amount Q2 or less (S30), the supply of muddy water to the downstream dam 5 is stopped (S30). S31).

The muddy water flows through the muddy water supply pipe 36 of FIG. 5 and is supplied downstream of the dam, and the turbidity of this muddy water is measured by the second turbidity meter 39 of FIG. 5 (S41).

Based on the measured turbidity information measured above and the discharge flow rate information of the dam at that time, the control device 41 redetermines the supply amount of muddy water in the same manner as in step S37 of FIG. 9, and as a result, the supply amount of muddy water (S42), the water supply control valve 35 is controlled to adjust the amount of water supplied to the mud drain tank 12 (S43).

Next, the flow rate of muddy water flowing through the muddy water supply pipe 36 is measured by the flow meter 40 of FIG. 5 (S44). When the control device 41 determines that the supply amount of muddy water is finely adjusted based on the measured flow rate information (S45), the control device 41 controls the muddy water control valve 38 and adjusts the supply amount of muddy water to the downstream of the dam (S46).

On the other hand, when the control device 41 determines that the turbidity of the muddy water is increased or decreased based on the measurement turbidity information from the turbidity measuring step S41 (S47), the electric motor 29 of the stirring device 20 of FIGS. 5 to 7 And the vertical movement device 23 are controlled, and the turbidity of the muddy water is adjusted by increasing or decreasing the amount of stirring of the silt clay content (S48). This turbidity-adjusted muddy water is supplied downstream of the dam.

As described above, according to the present embodiment, a dam sediment downstream reduction system capable of automatically controlling the amount of muddy water supplied to the downstream of the dam based on the relationship between the turbidity of the muddy water in the mud drain tank and the discharge rate of the dam is provided. realizable. In addition, it is possible to control the supply timing and supply amount of muddy water so that the downstream supply of silt clay after classification does not adversely affect the river.

That is, by controlling the supply timing of the muddy water to the downstream of the dam as shown in FIGS. 3 and 4, the muddy water can be supplied to the downstream of the dam at an appropriate supply timing. Further, the muddy water supply amount adjustment and the turbidity adjustment during the supply of muddy water to the downstream of the dam are performed based on the turbidity measurement and the flow rate measurement of the muddy water supplied to the downstream of the dam, so that the dam as shown in FIG. 4 Even if the muddy water supply amount is increased or decreased in accordance with the increase or decrease of the discharge flow rate (m ³ / sec), the muddy water supply amount (m ³ / sec) is determined in the same manner as in step S37 of FIG. As a result, the muddy water containing silt clay can be adjusted to an appropriate concentration, and even if it is supplied downstream of the dam, the permissible turbidity will not be exceeded in the downstream river, and no adverse effect on the river will occur.

The muddy water supply increase / decrease determination step (S42) and the muddy water turbidity increase / decrease determination step (S47) are the same as the muddy water supply amount determination step (step S37 in FIG. 9), and the allowable turbidity in the downstream river. It is done so as not to exceed.

According to the dam sediment downstream reduction system of the present embodiment, it is determined that a flood has occurred, muddy water is produced in the mud drain tank 12, and when the dam discharge amount reaches the predetermined value Q1, the muddy water is supplied to the downstream of the dam. When the specified value is Q2 or less, the supply of muddy water is stopped, and the amount of muddy water supplied is determined according to the discharge rate of the dam so that the muddy water does not exceed the allowable turbidity in the downstream river during the supply of muddy water. Each of these processes can be automatically controlled and can be operated remotely.

Next, another configuration example of the stirring device of the present embodiment will be described with reference to FIG. FIG. 11 is a perspective view showing another stirring device according to the present embodiment.

As shown in FIG. 11, the stirring device 50 is composed of an unmanned backhoe type, and is provided with a moving portion 51 that can move horizontally in the mud drain tank, an arm 52 extending from the moving portion 51, and the tip of the arm 52. A stirring unit 53 that is rotated by a rotation driving means such as an electric motor around a rotating shaft extending in a substantially horizontal direction is provided, and the moving unit 51 stirs while traveling on rails 50a to 50c provided in the mud drainage tank. As the portion 53 rotates, the silt clay content 6 in the mud drain tank is scraped from the surface and stirred.

The stirring device 50 is controlled by the same control system as in FIG. 8 and adjusts the stirring amount of the silt clay content 6 by controlling the traveling speed of the moving unit 51 and the rotation speed of the stirring unit 53, and the turbidity of muddy water. Can be adjusted.

In the case of FIG. 11, the configuration around the mud drain tank is the same as that of FIG. 5, but since the mud drain tank does not rotate, the pipes 31, 32, 34 and the mud water supply pipe 36 are directly connected to the mud drain tank. It may be configured to do so. Further, the stirring device 50 can be configured to be installed in a plurality of units.

Although the embodiment for carrying out the present invention has been described above, the present invention is not limited to these, and various modifications can be made within the scope of the technical idea of the present invention. For example, in FIG. 3, during a flood, water supply to the mud drain tank 12 was started (S22), and then the silt clay content was agitated (S23), but the present invention is not limited to this, and water supply and agitation are substantially the same. It may be started at the same time, or the stirring may be started and then the water supply may be performed.

Further, in the classification device 11 of FIG. 1, the drowned sediment is classified into silt clay having a particle size of 0.075 mm or less and sand having a particle size of more than 0.075 mm, but the present invention is not limited to this. For example, it may be classified into silt clay having a particle size of 0.075 mm or less and sand gravel having a particle size exceeding 0.075 mm. In this case, the gravel may be sand (particle size 0.075 to 2 mm) and fine gravel (particle size 2 to 19 mm), and may further contain gravel (particle size over 19 mm), although it depends on the dam.

Further, the configuration of the relative rotation between the mud drain tank 12 and the stirring section 21 in FIGS. 5 and 6 is such that the mud drain tank 12 rotates on its axis, but the present invention is not limited to this, and the stirring section is relative to the mud drain tank 12. 21 may be configured to rotate with the support shaft 22.

Further, if one of the soil removal plate and the jet nozzle of the stirring device 20 of FIGS. 6 and 7 can sufficiently stir the silt clay content, the other may be omitted.

Further, a muddy water storage tank may be installed immediately before the muddy water control valve 38 of the muddy water supply pipe 36 of FIG. 5 in order to stabilize the turbidity of the muddy water.

According to the dam deposit downstream reduction method and system of the present invention, the reservoir is dredged to maintain the reservoir capacity of the dam, and the silt clay contained in the sediment is supplied to the downstream river even if it is supplied to the downstream of the dam. Since there is no adverse effect, problems such as muddy water in the river and deterioration of the river environment can be prevented.

1 Dam 2 Reservoir 3 Sediment 4 Upstream 5 Dam downstream 6 Silt clay content 10 Dam deposit downstream reduction system 11 Classification device 12 Mud drain tank 13 Muddy water treatment device 14 Submersible pump 19 Dam downstream soil 20 Stirrer 21 Stirrer 21a ~ 21h Stirring rod 26a-26h Soil removal plate 22 Support shaft 23 Vertical movement device 24 Horizontal rotation device 27 Jet nozzle 28 First turbidity meter 29 Electric motor 35 Water supply control valve 36 Muddy water supply pipe 38 Muddy water control valve 39 Second turbidity Meter 40 Flow meter 41 Control device 50 Stirrer 51 Moving part 52 Arm 53 Stirring part JW Water jet Q Dam discharge

Claims (13)

It is a method of reducing the sediment downstream of the dam to supply the sediment of the reservoir of the dam downstream of the dam.
In normal times, the sediments dredged from the reservoir are classified into silt clay with a predetermined particle size or less and sand with a predetermined particle size or more.
The classified silt clay content is sent to the wastewater storage section, and
The silt clay content is stored and settled in the mud storage section, and then settled.
During a flood, water is supplied from the reservoir to the mud reservoir, the settled silt clay is agitated to form muddy water, and the muddy water is supplied downstream of the dam based on the discharge rate of the dam (m ³ / sec). ,
The dam deposit downstream reduction method in which the muddy water supply amount (m ³ / sec) is determined based on the discharge rate, the turbidity of the muddy water, and the allowable turbidity downstream of the dam. The method for reducing downstream of dam deposits according to claim 1, wherein the classified sand is placed downstream of the dam. The method for reducing downstream dam deposits according to claim 1 or 2, wherein the residual water of the supernatant in the wastewater storage section is discharged, treated with turbid water, and then returned to the reservoir. The method for reducing downstream of dam sediment according to any one of claims 1 to 3, wherein the supply of muddy water is started when the discharge rate becomes equal to or higher than a preset predetermined value. The dam deposition according to any one of claims 1 to 4, wherein the amount of muddy water supplied (m ³ / sec) is increased according to the increase in the discharge amount, and the supply of the muddy water is stopped in accordance with the convergence of the discharge amount. Product downstream reduction method. It is a dam sediment downstream reduction system that supplies the sediment of the dam reservoir to the downstream of the dam.
A classifying device that classifies sediments dredged from a reservoir into silt clay content of a predetermined particle size or less and sand exceeding the predetermined particle size.
A mud storage section that stores and precipitates the classified silt clay content,
A stirring device that stirs the silt clay content that has settled in the waste mud storage section, and
A pump that supplies water from the reservoir to the mud reservoir,
A first turbidity meter for measuring the turbidity of mud in the mud storage section is provided.
At the time of flood, water is supplied by the pump in the mud storage section, and the silt clay content is agitated by the stirrer to make muddy water, and the muddy water is used in the dam based on the discharge rate (m ³ / sec) of the dam. Configured to supply downstream ,
The amount of muddy water supplied (m ³ / sec) is controlled based on the discharge rate, the turbidity measured by the first turbidity meter, and the allowable turbidity downstream of the dam. Product downstream reduction system. A water supply control valve that controls the amount of water supplied from the reservoir,
A drainage control valve that controls the amount of drainage when the mud that has been agitated in the wastewater storage section is discharged,
Further equipped with a flow meter for measuring the flow rate of the discharged muddy water,
The amount of muddy water supplied can be increased or decreased by the water supply control valve.
The dam deposit downstream reduction system according to claim 6 , wherein the drainage control valve finely adjusts the supply amount of muddy water based on the measurement result by the flow meter. The downstream dam deposit reduction system according to claim 6 or 7 , further comprising a turbid water treatment device for treating the residual water of the supernatant in the effluent storage unit. The stirring device includes a stirring unit supported by a support shaft extending in the vertical direction and a rotating unit, and the rotation of the rotating unit causes the mud storage unit and the stirring unit to rotate relatively. The dam deposit downstream reduction system according to any one of claims 6 to 8 , wherein the stirring unit agitates the silt clay content of the wastewater storage unit. The stirring device includes a moving portion that can move horizontally in the mud storage section, an arm extending from the moving section, and a stirring section provided at the tip of the arm and rotating about a rotation axis extending in a substantially horizontal direction. The dam deposit downstream reduction system according to any one of claims 6 to 8 , wherein the stirring unit rotates due to the movement of the moving unit to agitate the silt clay content of the mud storage unit. Further provided with a second turbidity meter for measuring the turbidity of the mud discharged from the mud storage section.
The dam deposit downstream reduction system according to claim 9 , wherein the turbidity of the muddy water is increased or decreased by controlling the rotating portion of the stirring device based on the measurement result by the second turbidity meter. Further provided with a second turbidity meter for measuring the turbidity of the mud discharged from the mud storage section.
The dam deposit downstream reduction system according to claim 10, wherein the turbidity of the muddy water is increased or decreased by controlling the moving portion of the stirring device based on the measurement result by the second turbidity meter . The downstream reduction of dam sediment according to any one of claims 6 to 12 , wherein the pump and the stirring device are automatically operated based on the determination of the occurrence of the flood, and the supply amount of the muddy water is automatically controlled. system.

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