JP2019157516A - Method and system for returning dam deposit downstream - Google Patents

Abstract

To provide a method and a system for returning a dam deposit downstream, which does not adversely affect downstream rivers even if silt clay contained in the dam reservoir deposit is supplied downstream of the dam.SOLUTION: This method for returning a dam deposit downstream is a method for returning a dam deposit downstream that supplies deposit of a dam reservoir to the downstream of a dam, and comprises a step of classifying the deposit dredged from a reservoir 2 in a normal state into a silt clay component having a predetermined particle size or less and sand having a predetermined particle size, a step of sending the classified silt clay to a sludge reservoir 12, a step of storing and precipitating silt clay in the sludge reservoir, a step of supplying water from the reservoir to the sludge reservoir during floods, a step of stirring the precipitated silt clay to make mud water, and a step of supplying mud water downstream of the dam based on the discharge rate (m/sec) of the dam.SELECTED DRAWING: Figure 1

Description

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

  In the reservoir of the dam, the sediment flowing in from the upstream accumulates, and the water storage capacity decreases with the passage of time from the start of service. In addition, the riverbed in the upstream area of the dam has risen, and various adverse effects such as an increase in flood risk and a decrease in the riverbed and retreat of the coastline have occurred in the downstream area. In recent years, as countermeasures, sediments such as sediments from dams have been removed and discharged downstream (hereinafter also referred to as “supply”) based on the concept of “integrated sediment management”. ing.

JP 2002-294677 Japanese Patent Laid-Open No. 2001-164543 Japanese Patent Laid-Open No. 10-118697 Japanese Patent Laid-Open No. 2001-20318

  In the general sediment management, the most common method at present is dredging the reservoir, transporting the dredged soil to the downstream of the dam by a dump truck, and temporarily supplying it to the downstream of the dam during flooding. However, in the case of this soil laying method, if dredged soil containing excessive silt and clay is supplied as it causes long-term muddy water in the river, which is undesirable in the river environment, a clean silt clay content of 10% or less Only materials can be used as soiling materials.

  Also, if dredging is performed on dredged soil with a small amount of dam discharge during flooding, silt clay may remain in the river, which may adversely affect fish.

  The installation conditions of the dam where the sand discharge gate is installed (Unazuki Dam and Deppira Dam) are large for power generation and water use if the water level drops due to sand discharge and it takes time to recover the dam reservoir level. In order to have an impact, it is required that the river flow is sufficiently large relative to the water storage capacity.

  Patent Documents 1 and 2 propose a method for feeding and discharging underwater sediments using hydrostatic pressure. However, these suction methods and waste sand bypass require large-scale construction such as bypass tunnels and dam modifications. In addition, Patent Document 3 proposes to separate the slurry mixture into silt clay and organic matter in order to prevent long-term turbidization of the dam, and to return the silt clay component to the bottom of the dam to decompose the organic matter. This method increases the cost of dehydration and decomposition.

  Patent Document 4 classifies muddy water from the bottom mud dredged from the reservoir into sand gravel and silt clay, returns the gravel to the downstream river, and the silt clay is reprocessed as dewatered sludge after being dehydrated. Propose a method. However, the treatment of silt clay is not intended for downstream supply.

  In view of the problems of the prior art as described above, the present invention provides a method for downstream reduction of dam deposits that does not adversely affect downstream rivers even if silt clay content contained in the dam reservoir deposits is supplied downstream of the dam. And to provide a system.

In order to achieve the above object, the dam sediment downstream reduction method is a dam sediment downstream reduction method for supplying sediment from the dam reservoir to the downstream of the dam. The silt clay content is classified into a silt clay portion having a diameter equal to or less than the predetermined particle size, and the classified silt clay content is sent to a waste mud storage unit, and the silt clay content is stored and precipitated in the waste mud storage unit. , Water is supplied from the reservoir to the waste mud reservoir during flooding, the sedimented silt clay is agitated into mud, and the mud is supplied downstream of the dam based on the discharge rate of the dam (m ³ / sec) To do.

According to this dam sediment downstream reduction method, the reservoir of the dam is dredged in normal times, the dredged sediment is classified into silt clay and sand, and the classified silt clay is stored in the sludge storage section. In the event of a flood, water is supplied to the waste mud reservoir and the silt clay is agitated to form mud, which is then downstream of the dam based on the discharge rate (m ³ / sec) of the dam. Therefore, the muddy water can be supplied to the downstream of the dam when the flow rate is sufficiently high so that no silt clay remains in the downstream river. For this reason, even if silt clay in the reservoir sediment is supplied downstream of the dam, there is no adverse effect on the river.

  In the dam deposit downstream reduction method, the classified sand is preferably used as dam downstream soil. Thereby, 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 turbidity of the river. Such sand can be effectively used as an aggregate.

  Moreover, it is preferable to return to the reservoir after draining the supernatant surplus water in the waste mud reservoir and treating it with muddy water.

  Moreover, it is preferable to start supply of the muddy water when the discharge flow rate is equal to or higher than a predetermined value set in advance.

Further, it is preferable that the supply amount (m ³ / sec) of the muddy water is increased in accordance with the increase in the discharge flow rate, and the supply of the muddy water is stopped in accordance with the convergence of the discharge flow rate.

Moreover, it is preferable that the supply amount (m ³ / sec) of the muddy water is determined based on the discharge flow rate, the turbidity of the muddy water, and the allowable turbidity downstream of the dam. Thereby, even if the muddy water containing silt clay is supplied downstream, the downstream river does not exceed the allowable turbidity.

In order to achieve the above object, the dam sediment downstream reduction system is a dam sediment downstream reduction system that supplies the sediment of the dam reservoir to the downstream of the dam, and deposits dredged from the reservoir below a predetermined particle size. A classification device for classifying the silt clay into sand having a predetermined particle size, a waste mud storage section for storing and precipitating the classified silt clay, and a silt clay fraction precipitated in the waste mud storage section And a pump for supplying water to the waste mud reservoir from the reservoir, and the silt clay is agitated by the agitator while being fed by the pump in the waste mud reservoir during a flood. The muddy water is supplied to the downstream of the dam based on the discharge rate (m ³ / sec) of the dam.

According to this dam sediment downstream reduction system, the sediment dredged from the dam reservoir in normal times is classified into silt clay and sand using a classifier, and the classified silt clay is stored in the sludge storage section. In the event of a flood, water is pumped from the reservoir to the mud reservoir and the silt clay is agitated with a stirrer to form mud, which is then discharged into the dam (m ³ / s ), The mud can be supplied downstream of the dam at a sufficient discharge rate so that no silt clay remains in the river downstream of the dam. For this reason, even if silt clay in the reservoir sediment is supplied downstream of the dam, there is no adverse effect on the river.

The dam sediment downstream reduction system further includes a first turbidity meter for measuring the turbidity of the muddy water in the waste mud reservoir, and the supply amount of muddy water (m ³ / sec) is the discharge flow rate, It is preferable to control based on the turbidity measured by the first turbidimeter and the allowable turbidity downstream of the dam. Thereby, even if the muddy water containing silt clay is supplied downstream, the allowable turbidity is not exceeded in the downstream river.

  In addition, 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 discharging the mud stirred in the waste mud reservoir, and the flow rate of the discharged mud water are measured. It is preferable that the flow rate of the muddy water is further increased and decreased by the water supply control valve, and the muddy water supply amount is finely adjusted by the drainage control valve based on the measurement result of the flow meter. .

  Moreover, it is preferable to further include a turbid water treatment device for treating the supernatant surplus water in the waste mud storage section with turbid water.

  The stirring device includes a stirring unit supported by a support shaft extending in a vertical direction, and a rotating unit, and relatively rotates the waste mud storage unit and the stirring unit by rotation of the rotating unit. It is preferable that the stirring unit is configured to stir the silt clay content of the waste mud storage unit. In addition, it is preferable to comprise so that a support shaft may move below with a stirring part with relative rotation of a sludge storage part and a stirring part.

  In addition, the stirring device includes a moving unit that can move horizontally in the waste mud storage unit, an arm that extends from the moving unit, and a stirring that rotates about a rotation axis that is provided at the tip of the arm and extends in a substantially horizontal direction. And the stirring clay is rotated by the movement of the moving part, and the silt clay content of the mud storage part may be stirred.

  Further, the apparatus further comprises a turbidimeter for measuring the turbidity of the discharged muddy water, and increasing or decreasing the turbidity of the muddy water based on a measurement result by the turbidimeter of the rotating unit or the moving unit 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 and the supply amount of the muddy water is automatically controlled. Thereby, 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 the pump is automatically selected based on various information such as the precipitation data and the water level of the dam. You may comprise so that a stirring apparatus may operate | move.

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

FIG. 1 is a diagram schematically showing a dam sediment downstream reduction system according to the present embodiment and a dam around the dam deposit downstream reduction system. It is a flowchart for demonstrating the process in the normal time of the dam deposit downstream reduction method by this embodiment. It is a flowchart for demonstrating the main processes at the time of the flood of the dam deposit downstream reduction method by this embodiment. In this embodiment, it is a graph which shows roughly the relationship between discharge flow rate and time, in order to demonstrate the timing which supplies and stops mud water downstream of a dam. FIG. 2 is a perspective view schematically showing a configuration of a waste mud tank, a stirring device, and the surroundings thereof in FIG. 1. It is a top view which shows the stirring part in the sludge tank of FIG. It is the figure seen by cut | disconnecting in the VII-VII line direction of FIG. It is a block diagram which shows roughly the control system of the dam deposit downstream reduction system by this embodiment. FIG. 6 is a flowchart for explaining the respective steps of measuring the turbidity of mud water before the downstream supply of the dam and determining the supply amount of the mud water downstream of the dam in the waste mud tank of FIGS. 1 and 5. It is a flowchart for demonstrating each process of supply amount adjustment and turbidity adjustment after muddy water downstream supply. 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 sediment downstream reduction system according to the present embodiment and a dam around the dam deposit downstream reduction system.

  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 flows into the reservoir 2 from the upstream 4 to trap sediment 3 such as sediment. The classifier 11 classifies the dredged sediment into silt clay having a particle size of 0.075 mm or less and sand having a particle size exceeding 0.075 mm, and the silt clay sent from the classifier 11 by pipeline pumping. A mud tank 12 having an agitating device that stirs and settles silt clay deposited during flooding, a turbid water treatment device 13 that treats surplus water in the supernatant of the mud tank 12 and returns it to the reservoir 2; A submersible pump 14 for supplying water to the sludge tank 12. During the flood, the mud tank 12 agitates the silt clay that has been settled and turns it into muddy water. The muddy water is discharged to the downstream 5 of the dam 1 and supplied.

  As the classifier 11, various known classifiers / classifiers can be used. For example, a spiral classifier, a drag classifier, a rotary classifier, a hydraulic classifier, a sizer, a wet cyclone, or the like can be used.

  The turbid water treatment device 13 can use various known turbid water treatment devices and turbid water treatment plants. For example, the turbid water treatment device 13 has various treatment functions such as sedimentation separation, neutralization, and waste mud of the suspension, and treatment with low turbidity. A muddy water treatment device or the like that discharges water can be used.

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

  First, as shown in FIGS. 1 and 2, the sediment 3 such as earth and sand accumulated in the reservoir 2 is dredged by a dredger or the like (S01), and the dredged sediment is classified by the classifier 11 (S02). ), The classified sand having a particle size exceeding 0.075 mm (S03) and the silt clay component having a particle size of 0.075 mm or less (S04) are treated as follows.

  That is, the sand having a particle size exceeding 0.075 mm is temporarily placed in the temporary storage site 18 (S05), and then transported by a dump truck or the like to be the dam downstream soil 19 (S06). (S07).

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

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

  Next, when it is determined that a flood has occurred as shown in FIGS. 1 and 3 during a flood (S21), water supply from the reservoir 2 to the mud tank 12 is started by the submersible pump 14 (S22). The silt clay deposited in the tank 12 is stirred by a stirrer (S23), and muddy water is produced (S24). In the water supply step S <b> 22, it is preferable that the surface water of the dam lake (turbidity of about 50 PPM or less) is taken and supplied to the mud tank 12.

  The determination step S21 of flood occurrence is usually performed by the dam manager based on various flood information such as precipitation in the upstream area of the dam and the water level of the dam reservoir. You may make it judge by the control apparatus 41 (FIG. 8) of a control system receiving a signal. Moreover, you may comprise so that the control apparatus 41 (FIG. 8) may judge automatically based on these flood information.

  In FIG. 3, the water supply process S22 and the agitation process S23 for producing muddy water are started after the flood occurrence determination process S21. Usually, there is a certain amount of time from the time of the flood occurrence determination to the start of dam discharge. So you can make muddy water in the meantime. Further, as shown in FIG. 4, since there is a certain amount of time from the start of dam discharge until the time when the muddy water is supplied downstream (T1), the water supply step S22 and the stirring step S23 may be started after confirmation of the start of dam discharge. Good.

  After the occurrence of the flood, discharge is started from the regular spillway of the dam 1 (S25), and when the water level in 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 finished and the water level in the dam downstream 5 is lowered and restored, the supply of the dam downstream soil 19 to the dam downstream 5 is finished.

Further, as shown in FIG. 4, when the discharge flow rate Q (m ³ / sec) per unit time from the dam 1 increases with time and becomes equal to or greater than a first predetermined amount Q1 preset at time T1 (S27), Muddy water is discharged from the mud tank 12 and supplied to the dam downstream 5 (S28). The first predetermined amount Q1 is set to a sufficient discharge rate so that no silt clay remains in the river downstream of the dam.

As shown in FIG. 4, the discharge rate Q (m ³ / sec) from dam 1 during flooding increases with time, eventually reaches the peak discharge rate (S29), and then decreases with time. When it becomes less than or equal to the second predetermined amount Q2 preset in T2 (S30), the supply of muddy water to the dam downstream 5 is stopped (S31).

According to the dam sediment downstream reduction method of the present embodiment, the sediment dredged from the reservoir of the dam in normal times is classified into silt clay and sand by the classifier 11, and the classified silt clay is classified into the sludge tank. 12 is stored and settled, and when a flood occurs, water is supplied from the reservoir 2 to the mud tank 12 by the submersible pump 14, the precipitated silt clay is stirred into mud, and the mud is discharged into the dam 1 When (m ³ / sec) reaches a sufficient discharge flow rate (first predetermined amount Q1 in FIG. 4) such that no silt clay remains in the river downstream of the dam, it is supplied downstream of the dam. For this reason, 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 downstream of the dam, the river is not adversely affected.

In the conventional general laying method, earth and sand are placed directly on the river channel downstream of the dam, so when the flood is small, the laying material does not flow, and silt clay remains in the river channel. Could have an adverse effect on On the other hand, according to the present embodiment, when a flood of a certain scale or larger occurs, that is, the discharge flow rate Q (m ³ / sec) per unit time of the dam 1 becomes the first predetermined amount Q1 or more. When the mud containing silt clay is supplied downstream, the silt clay does not remain in the river channel downstream of the dam.

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

  In addition, as shown in FIG. 4, the downstream supply of muddy water is started at time T1 and the discharge rate Q1 of the dam, and the downstream supply of muddy water is stopped at time T2 and the discharge rate Q2 of the dam, but Q1 <Q2 is set. By setting the discharge rate Q2 of the dam at the time of stopping the supply of muddy water to a high level, the muddy water flows after the supply of muddy water stops, and no silt clay remains in the river channel downstream of the dam. It can be returned to the correct state.

  Moreover, even if the deposit is rich in silt clay and not originally suitable for river reduction, it can be improved to a material suitable for river reduction by classifying the deposit after dredging. As a result, the riverbed can be lowered and a desirable fish habitat can be realized.

  In addition, the dam sediment downstream reduction method and system taking into account the river environment during floods by supplying silt clay as muddy water from the mud tank based on the most well-proven and low-cost initial construction method. Can provide. Since a large-scale construction such as the suction method and the sand discharge bypass tunnel of Patent Documents 1 and 2 is unnecessary, the initial cost is low.

  Moreover, compared with the construction method by the general dredging method and the soil laying method, a soil disposal site is unnecessary, and only the transport of sand is sufficient, and the running cost is reduced, so the running cost is low.

  Next, the configuration of the waste mud tank, the stirring device and the surroundings of the dam deposit downstream reduction system of FIG. 1 will be described with reference to FIGS. FIG. 5 is a perspective view schematically showing the configuration of the waste mud tank, the agitation device, and the surroundings of FIG. FIG. 6 is a plan view showing a stirring portion in the mud tank of FIG. FIG. 7 is a view taken along line VII-VII in FIG.

  As shown in FIG. 5, the sludge tank 12 is configured in a cylindrical shape, is configured so that a silt clay component can settle and be stored therein, and has a stirring device 20 for stirring the precipitated silt clay component. In addition, although the mud tank 12 is installed in the ground so that rotation is possible, the installation structure is abbreviate | omitting illustration in FIG. In addition, a plurality of waste mud tanks 12 having the stirring device 20 may be installed.

  The stirring device 20 stirs the support shaft 22, the stirring portion 21 extending in the horizontal direction within the mud tank 12, the support shaft 22 positioned at the center of the mud tank 12 and extending in the vertical direction to support the stirring portion 21. A vertical movement device 23 that moves vertically with the unit 21 and a horizontal rotation device 24 that rotates the mud tank 12 with respect to the stirring unit 21 and the support shaft 22 in order to stir the silt clay 6 in the mud tank 12. And comprising.

  As shown in FIGS. 5 to 7, the stirring unit 21 has a plurality of stirring rods 21 a to 21 h extending radially from the central support shaft 22 in the radial direction of the mud tank 12. The plurality of stirring rods 21a to 21h are arranged at equal intervals in the circumferential direction, and are stirred by inclining downward from the lower ends of the respective stirring rods 21a to 21h by scraping the silt clay portion 6 in the waste mud tank 12. And the jet nozzle 27 that ejects the jet water JW from the water supply pipe 27a toward the silt clay portion 6 along each of the soil discharge plates 26a to 26h.

  As shown in FIG. 6, the earth discharging plates 26 a to 26 h are shorter in the horizontal direction than the horizontal lengths of the respective stirring bars 21 a to 21 h, and each radial position is different from the adjacent earth discharging plates, As a whole, the earth removing plates 26a to 26h are configured to be evenly located from the support shaft 22 to the outer periphery in the radial direction. When the sludge tank 12 rotates in the rotation direction R, as shown in FIGS. 6 and 7, each of the soil discharge plates 26 a to 26 h ejects the jet water JW from the jet nozzle 27 to the silt clay component 6 and removes the silt clay component 6. It can be scraped off from the surface little by little and stirred. Moreover, even silt clay solidified by jetting of jet water JW from the jet nozzle 27 can be sufficiently thawed.

  As shown in FIG. 5, the vertical moving device 23 is disposed in the horizontal portion 25 above the mud tank 12 and has a known electric spindle structure. The vertical moving device 23 is engaged with the screw portion 22 a of the support shaft 22 to rotate. This is converted into linear movement of the support shaft 22. Thereby, the stirring part 21 can be moved to the lower part of FIG. 7 with the support shaft 22 according to progress of stirring of a silt clay part, and the silt clay part 6 in the waste mud tank 12 can be stirred from the upper part to the lower part. In addition, the horizontal part 25 is supported by the support bodies 25a-25d.

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

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

  As shown in FIG. 5, the dam deposit downstream reduction system 10 has a pipe 31 extending from the classifier 11 of FIG. 1 to the waste mud tank 12, and the silt clay fraction classified by the classifier 11 is pumped through the pipe 31. It is sent to the mud tank 12.

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

  1 has a pipe 34 extending from the submersible pump 14 of the reservoir 2 to the mud tank 12 and is supplied to the mud tank 12 from the reservoir 2 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.

  5 has a muddy water supply pipe 36 extending from the upper part of the muddy water tank 12 to the downstream 5 of the dam in FIG. 1 and a muddy water pump 37, and muddy water produced from silt clay in the muddy water tank 12 is muddy water. It is supplied to the dam downstream 5 through the mud supply pipe 36 by the operation of the pump 37. The supply of the muddy water to the dam downstream 5 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 mud water in the mud tank 12 is disposed in the mud tank 12. Further, in the muddy water supply pipe 36 of FIG. 5, a second turbidimeter 39 for measuring the turbidity of the muddy water supplied downstream of the dam is arranged upstream of the muddy water control valve 38, and the muddy water control valve 38. The flow meter 40 which measures the flow volume of muddy water is arrange | positioned in the downstream.

  Next, a control system for automatically controlling the dam deposit downstream reduction system 10 shown in 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 that receives various information and measurement information and sends a control signal to each unit. The control device 41 is composed of, for example, a personal computer (PC), and includes a CPU (central processing unit) that executes various controls, and a memory that includes a RAM and the like that temporarily stores programs and various information during control. A program for executing each step of the dam deposit downstream reduction method according to the present embodiment is 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.

  In the control device 41, as shown in FIG. 8, the measured turbidity information in the mud tank 12 of FIG. 5 measured by the first turbidimeter 28, and measured by the second turbidimeter 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. In addition, allowable turbidity information, flood information, and dam discharge information in the river downstream of the dam are input.

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

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

  Steps S21 to S24 in FIG. 9 are the same as those in FIG. 3, but in the flood occurrence determination step S21 in FIG. 9, various types of flood information such as precipitation in the upstream area of the dam and the water level of the dam reservoir are shown in FIG. The control device 41 in FIG. 8 automatically determines the occurrence of a flood based on the 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 through the pipe 34 into the mud tank 12 (S22).

  Moreover, the control apparatus 41 operates the electric motor 29 of the stirring apparatus 20, and rotates the waste mud tank 12 with respect to the stirring part 21, so that the earth discharging plates 26a to 26h of the stirring bars 21a to 21h are as shown in FIG. In this way, the silt clay content 6 in the waste mud tank 12 is scraped off and stirred (S23). At this time, the jetting water JW is ejected from the jet nozzle 27, whereby the stirring efficiency is improved. Further, the vertical movement device 23 is operated in accordance with the stirring by the stirring unit 21 to move the stirring unit 21 downward.

  The muddy water is produced in the waste mud tank 12 by the above-mentioned water supply step S22 and the stirring step S23 (S24), and the turbidity of this muddy water is measured by the first turbidity meter 28 in the mud tank 12 (S35). .

  When adjusting the turbidity of the mud in the mud tank 12 based on the turbidity measurement result (S36), the rotational 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 are used. The turbidity of the muddy water can be adjusted by controlling the downward movement speed of the muddy water.

Next, the control device 41 inputs the measured turbidity information of the muddy water in the mud tank 12 by the first turbidity meter 28, the allowable turbidity information in the river downstream of the dam, and the discharge amount of the dam ( m ³ / sec) information is used to determine the amount of muddy water supply (m ³ / sec) downstream of the dam (S37). The allowable turbidity is determined for each river in consideration of the influence on fish and plants that live.

  As described above, the amount of muddy water supplied to the dam downstream 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 produced, and even if supplied to the downstream of the dam, the allowable turbidity is not exceeded in the downstream river, and no adverse effects on the river occur.

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

  It is determined whether or not the dam discharge flow rate Q is within a 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. The supplied mud is supplied from the mud tank 12 to the downstream 5 of the dam through the mud supply pipe 36 by operating the mud 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 muddy water supply amount to the downstream of the dam becomes the determined supply amount.

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

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

  Based on the measured turbidity information and the discharge information of the dam at that time, the control device 41 determines the supply amount of muddy water again in the same manner as in step S37 of FIG. If it is determined to increase or decrease (S42), the water supply control valve 35 is controlled to adjust the water supply amount to the mud tank 12 (S43).

  Next, the flow rate of the 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 to finely adjust the amount of supplied muddy water based on the measured flow rate information (S45), it controls the muddy water control valve 38 to adjust the amount of supplied muddy water downstream of the dam (S46).

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

  As described above, according to the present embodiment, the dam deposit downstream reduction system that can automatically control the amount of muddy water supplied to the dam downstream from the relationship between the turbidity of the muddy water in the waste mud tank and the discharge amount of the dam. realizable. In addition, the muddy water supply timing and amount can be controlled so that the downstream supply of the silt clay after classification does not adversely affect the river.

That is, by controlling the supply timing of the muddy water downstream of the dam as shown in FIGS. 3 and 4, muddy water can be supplied downstream of the dam at an appropriate supply timing. In addition, the supply amount and turbidity adjustment of the muddy water during the supply to the downstream of the muddy water are performed based on the turbidity measurement and flow rate measurement of the muddy water supplied to the downstream of the dam. Even if the supply amount of muddy water is increased / decreased in accordance with the increase / decrease of the discharge flow rate (m ³ / sec), the supply amount (m ³ / sec) of muddy water is determined in the same manner as in step S37 of FIG. Thus, the muddy water containing silt clay can be made to an appropriate concentration, and even if supplied to the downstream of the dam, the allowable turbidity is not exceeded in the downstream river, and the river is not adversely affected.

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

  According to the dam sediment downstream reduction system of the present embodiment, the occurrence of flooding is determined, mud is produced in the mud tank 12, and when the dam discharge amount reaches a predetermined value Q1, the mud is supplied downstream of the dam, When the specified value Q2 or less, the supply of mud water is stopped, and during the mud water supply, the mud water supply amount is determined in accordance with the discharge rate of the dam so that the allowable turbidity is not exceeded in the downstream river. Each of these processes can be automatically controlled, and remote operation is also possible.

  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 this embodiment.

  As shown in FIG. 11, the agitation device 50 is configured by an unmanned backhoe type, and is provided at a moving part 51 that can move horizontally in the waste mud tank, an arm 52 that extends from the moving part 51, and a tip of the arm 52. An agitating portion 53 that is rotated by a rotation driving means such as an electric motor around a rotating shaft that extends in a substantially horizontal direction, and the agitating portion 51 is agitated while the moving portion 51 travels on rails 50a to 50c provided in the sludge tank. As the part 53 rotates, the silt clay content 6 in the mud tank is scraped off from the surface and stirred.

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

  In the case of FIG. 11, the configuration around the waste mud tank is the same as in FIG. 5, but since the waste mud tank does not rotate, the pipes 31, 32, 34 and the mud supply pipe 36 are directly connected to the waste mud tank. You may comprise. Further, a plurality of stirring devices 50 can be installed.

  As described above, the modes for carrying out the present invention have been described. However, 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, water supply to the sludge tank 12 is started at the time of flooding (S22), and the silt clay content is stirred (S23). However, the present invention is not limited to this, and water supply and stirring are almost performed. It may be started at the same time, or water may be supplied after stirring is started.

  In addition, in the classifying device 11 of FIG. 1, the trapped sediment is classified into silt clay having a particle size of 0.075 mm or less and sand having a particle size exceeding 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 gravel having a particle size exceeding 0.075 mm. In this case, the gravel differs depending on the dam, but may be sand (particle size 0.075 to 2 mm) and fine gravel (particle size 2 to 19 mm), and may further include gravels (particle size over 19 mm).

  5 and 6, the configuration of relative rotation between the mud tank 12 and the stirring unit 21 is configured to rotate the mud tank 12. However, the configuration is not limited to this, and the stirring unit is not limited to the mud tank 12. 21 may be configured to rotate together with the support shaft 22.

  In addition, when either one of the earth discharging plate and the jet nozzle of the stirring device 20 of FIGS. 6 and 7 can sufficiently stir the silt clay, 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 in FIG. 5 in order to stabilize the muddy water turbidity.

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

DESCRIPTION OF SYMBOLS 1 Dam 2 Reservoir 3 Sediment 4 Upstream 5 Dam downstream 6 Silt clay content 10 Dam sediment downstream reduction system 11 Classification device 12 Mud tank 13 Muddy water treatment device 14 Submersible pump 19 Dam downstream soil 20 Stirring device 21 Stirring part 21a- 21h Stirring rods 26a to 26h Earth 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 Mud supply pipe 38 Mud water control valve 39 Second turbidity Meter 40 Flow meter 41 Control device 50 Stirrer 51 Moving unit 52 Arm 53 Stirrer JW Jet water Q Dam discharge

Claims (14)

A dam sediment downstream reduction method for supplying sediment from a dam reservoir downstream of a dam,
The sediment dredged from the reservoir in normal times is classified into a silt clay content of a predetermined particle size or less and sand exceeding the predetermined particle size,
Send the classified silt clay to the mud storage,
The silt clay content is stored and settled in the mud storage part,
During the flooding, water is supplied from the reservoir to the waste mud reservoir, the precipitated silt clay is stirred into mud, and the mud is supplied downstream of the dam based on the discharge rate (m ³ / sec) of the dam. Dam sediment downstream reduction method.   The dam deposit downstream reduction method according to claim 1, wherein the classified sand is used as dam downstream soil.   The method for downstream reduction of dam deposits according to claim 1 or 2, wherein surplus water in the supernatant in the waste mud reservoir is discharged and treated with muddy water and then returned to the reservoir.   The dam deposit downstream reduction method according to any one of claims 1 to 3, wherein supply of the muddy water is started when the discharge flow rate becomes equal to or higher than a predetermined value set in advance. The dam deposition according to any one of claims 1 to 4, wherein the supply amount (m ³ / sec) of the muddy water is increased in accordance with an increase in the discharge flow rate, and the supply of the muddy water is stopped in accordance with the convergence of the discharge flow rate. Product downstream reduction method. The supply amount (m ³ / sec) of the muddy water is determined based on the discharge flow rate, the turbidity of the muddy water, and the allowable turbidity downstream of the dam. Dam sediment downstream reduction method. A dam sediment downstream reduction system that supplies dam reservoir sediment downstream of the dam,
A classification device for classifying the sediment dredged from the reservoir into silt clay having a predetermined particle size or less and sand having the predetermined particle size;
A mud storage part for storing and precipitating the classified silt clay, and
An agitation device for agitating the silt clay content precipitated in the waste mud reservoir;
A pump for supplying water from the reservoir to the waste mud reservoir,
At the time of flooding, water is supplied by the pump in the mud storage section and the silt clay is stirred by the stirring device to become mud, and the mud is discharged from the dam based on the discharge rate (m ³ / sec) of the dam. A dam sediment downstream reduction system configured to feed downstream. Further comprising a first turbidity meter for measuring the turbidity of the muddy water in the waste mud reservoir,
The supply amount (m ³ / sec) of the muddy water is controlled based on the discharge flow rate, the turbidity measured by the first turbidimeter, and the allowable turbidity downstream of the dam. The dam sediment downstream reduction system according to claim 7. A water supply control valve for controlling the amount of water supplied from the reservoir;
A drainage control valve for controlling the amount of drainage when discharging the mud stirred in the waste mud reservoir,
A flow meter for measuring the flow rate of the discharged muddy water,
Increase / decrease the supply amount of the muddy water by the water supply control valve,
The dam deposit downstream reduction system according to claim 7 or 8, wherein fine adjustment of the supply amount of the muddy water is performed by the drainage control valve based on a measurement result by the flow meter.   The dam deposit downstream reduction system according to any one of claims 7 to 9, further comprising a turbid water treatment device for treating turbid water of supernatant water in the waste mud reservoir.   The stirring device includes a stirring unit supported by a support shaft extending in a vertical direction, and a rotating unit, and relatively rotates the waste mud storage unit and the stirring unit by rotation of the rotating unit. The dam deposit downstream reduction system according to any one of claims 7 to 10, wherein the agitation unit agitates the silt clay content in the waste mud storage unit.   The stirring device includes a moving unit that can move horizontally within the waste mud storage unit, an arm that extends from the moving unit, and a stirring unit that is provided at the tip of the arm and rotates about a rotating shaft that extends in a substantially horizontal direction. The dam deposit downstream reduction system according to claim 7, wherein the silt clay content of the waste mud storage unit is stirred while the stirring unit is rotated by the movement of the moving unit. A second turbidity meter for measuring the turbidity of the mud discharged from the waste mud reservoir,
The dam sediment downstream reduction system according to claim 11 or 12, wherein the turbidity of the muddy water is increased or decreased by controlling the rotating unit or the moving unit of the stirring device based on a measurement result by the second turbidimeter. .   The dam deposit downstream reduction according to any one of claims 7 to 13, 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.

Images