JP5116627B2 - Sedimentation amount determination support method and sedimentation amount determination support device - Google Patents

Description

  The present invention relates to a method and apparatus for assisting in determining the amount of sand when placing sand from the upstream side to the downstream side of a dam.

  At dams and dams at hydroelectric power stations, the sediment flowing from the upstream is blocked, so the amount of sediment supplied to the downstream of the dam, etc. decreases, and the coastline is reduced and armored (the composition of the riverbed) The problem is that the material is only large stones and gravel.

As a countermeasure against such a problem, there is a case in which earth and sand dammed by a dam or the like is moved downstream, and sand is placed to return the earth and sand downstream when a flood occurs (see FIG. 6). Sedimentation has advantages such as being able to naturally supply sediment to the downstream, and reducing transportation costs (costs) to a remote disposal site. Note that Non-Patent Document 1 describes sand placement (on the literature, sand placement).
“Prefecture (7/7) to Sediment River and Sagami River in Sakai River” (7/7), [Online], 7/7/2006, Kanagawa, [Search on August 1, 2008], Internet <URL : http://www.kentsu.co.jp/kanagawa/news/p01797.html>

  However, in the past, sufficient studies have not been made on how to determine how much earth and sand should be placed downstream of a dam or the like. For example, when the amount of sand is too much, earth and sand remain downstream, so there is a concern about the load on the surrounding environment (for example, the impact on the ecosystem and landscape). On the other hand, when the amount of sand is too small, the above-mentioned problems such as coastline reduction and armoring cannot be solved.

  This invention is made | formed in view of the said subject, The main objective is to determine the suitable amount of sand placement in the dam of a hydroelectric power station.

In order to solve the above-mentioned problem, the present invention is a settling amount determination support method used when determining the amount of settling sand that is earth and sand to be transferred from the upstream side to the downstream side of a dam of a hydroelectric power plant, Includes formula data representing each equation of Michigami Kamata's equation regarding the equation of motion of the conservation equation of mass as the basic equation of flow, the equation of motion of the conservation equation of momentum as the basic equation of flow and the amount of scavenging sand, and the amount of the settling sand A computer having a storage unit storing the dam and downstream terrain condition data and water discharge pattern data indicating a temporal change in flow rate relating to the water to flow downstream from the settling sand, and ends from the start of the water discharge Steps (1) to (5) are executed at predetermined time intervals until
(1) A step of obtaining the flow rate of the water discharge from the water discharge pattern data (2) A cross-sectional area of the water flow at each position downstream from the dam by applying the discrete formula of the law of conservation of mass. And (3) calculating the flow rate and flow velocity of the flowing water at each position from the topographic condition data and the cross-sectional area by applying the equation of motion of the momentum conservation law. A step of calculating the amount of sediment movement at each position from the topographic condition data and the flow velocity by applying the Michigami formula (5) a step of calculating the bed height at each position from the amount of sediment movement Further, the step of displaying the river bed height at each position at the end of the water discharge is performed.

  According to this method, since the state of the earth and sand moved by the flooding can be understood for each amount of sand set, an appropriate amount of sand set can be determined by referring to and evaluating the situation after the earth and sand related to the different amount of sand set. Can be determined.

Further, the present invention is a method for determining the amount of sand placed, wherein the computer displays the river bed height after calculating the river bed height at each position at each predetermined time. To do.
According to this method, the riverbed height at each position is displayed at each predetermined time, so that it is possible to grasp the state in which the earth and sand are moving due to flooding.

  Note that the present invention includes a set amount determination support device. In addition, the problems disclosed in the present application and the solutions thereof will be clarified by the column of the best mode for carrying out the invention and the drawings.

  According to the present invention, it is possible to determine an appropriate amount of sand set in a dam of a hydroelectric power plant.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. The sedimentation amount determination support device according to the embodiment of the present invention provides data on terrain conditions of dams and rivers (downstream) of hydroelectric power plants including the amount of sedimentation and data on water discharge that occurs once a year. It is acquired, and the state that the sand is carried downstream is simulated and output. According to this, an appropriate amount of sand can be determined by referring to and evaluating the result of the simulation of sediment movement related to different amounts of sand.

<< Device and data configuration >>
FIG. 1 is a diagram illustrating a hardware configuration of the sand placement determination support device 1 and a data configuration of the storage unit 15. FIG. 1A shows a hardware configuration of the sand placement determination support device 1. The sand placement determination support device 1 includes a communication unit 11, a display unit 12, an input unit 13, a processing unit 14, and a storage unit 15. The communication unit 11 is a part that performs IP communication with other devices via a network, and is realized by, for example, a NIC (Network Interface Card) or the like. The display unit 12 is a part that displays data according to an instruction from the processing unit 14, and is realized by, for example, a liquid crystal display (LCD). The input unit 13 is a part where an operator inputs data (for example, data on terrain conditions and water discharge patterns), and is realized by, for example, a keyboard or a mouse. The processing unit 14 transfers data between the units and controls the entire sand placement determination support device 1. A CPU (Central Processing Unit) executes a program stored in a predetermined memory. Is realized. The storage unit 15 stores data from the processing unit 14 and reads the stored data, and is realized by, for example, a nonvolatile storage device such as a flash memory or a hard disk device. The storage unit 15 includes data on topographic conditions of hydroelectric power plant dams and rivers including the amount of sedimentation, data on water discharge patterns indicating temporal changes in the amount of water discharged from the dam to the downstream, and mass conservation laws The data of the continuous equation, the equation of motion of the momentum conservation law and the Michigami Hamada equation are stored in advance.

  The sand placement determination support device 1 may be a stand-alone device (PC (Personal Computer) or the like), or a device (server or the like) that can communicate with a plurality of terminals via a network. May be. In the case of a stand-alone device, it is not necessary to provide the communication unit 11. When communication with a plurality of terminals is possible, data on topographic conditions and water discharge patterns may be received from the terminals.

  FIG. 1B shows the configuration of data stored in the storage unit 15. In the storage unit 15, calculation formula data 15A, terrain condition data 15B, and flood pattern data 15C are stored in advance. The calculation formula data 15A is data of a calculation formula used in the simulation. The calculation formula data 15A relates to a continuous equation and a discrete formula of the law of conservation of mass as the basic formula of the flow, a motion equation of the law of conservation of momentum as the basic formula of the flow, and the amount of scavenging sand There is Michigami Kamata ceremony. The terrain condition data 15B is data relating to the terrain of the dam and the river, and includes the height of the riverbed including the amount of sand, the river width, the dam height, the average particle size of the riverbed material, and the like. The water discharge pattern data 15 </ b> C is data indicating a temporal change in the flow rate related to the water discharged to flow the set sand downstream.

≪Device processing≫
FIG. 2 is a flowchart showing a simulation process by the sand placement determination support device 1. This process performs a simulation of earth and sand movement related to one set amount of sand, and the operator refers to and evaluates the result of the simulation of a different set amount of sand using the set amount of sand determination support device 1. Determine the appropriate amount of sand.

  First, the sand placement determination support device 1 acquires data on the terrain condition including the sand placement amount via the communication unit 11 and the input unit 13 (S201). The terrain condition data includes river width B, river height H, average particle size d of earth and sand (bed material), dam height, roughness coefficient, and the like. The longitudinal height H of the river is a distribution H (x) of the river bed height at the position x in the flow direction, and includes the river bed that has been raised by the sand placement. The acquired terrain condition data is stored in the terrain condition data 15B of the storage unit 15.

Next, the sand placement determination support device 1 acquires data of a water discharge pattern that is expected to occur about once a year via the communication unit 11 and the input unit 13 (S202). Flooding is water that flows downstream from a dam of a hydroelectric power plant, and is caused by natural flooding or forced dam opening. FIG. 3 is a graph showing an example of a water discharge pattern. The elapsed time [hour] is taken on the horizontal axis, and the flow rate [m ³ / s] is taken on the vertical axis, showing the temporal change of the flow rate. The acquired water discharge pattern data is stored in the water discharge pattern data 15 </ b> C of the storage unit 15.

  Then, the sand placement determination support device 1 initializes the time t (S203). The time t is a reference time in the calculation processing (processing for specifying the shape of the river bed at the time t) to be executed next from S204 to S208. As an initial value, for example, the start time (0hour) of water discharge is set. Is set.

First, the sand placement determination support device 1 acquires the flow rate Q ⁿ⁻¹ at time t−Δt from the water discharge pattern data 15C of the storage unit 15 (S204). n is a subscript relating to time t, and n−1 is a subscript relating to time t−Δt.

Next, the sand placement determination support device 1 obtains the cross-sectional area ^An and the water depth h at the time t and each position x by the continuous equation of the mass conservation law of the calculation formula data 15A (S205). Expression 1 shown below is a continuous expression of the law of conservation of mass, and Expression 2 is obtained by discretizing the expression with respect to the cross-sectional area A (discrete expression) in order to perform numerical calculation. Then, as shown in Equation 3, when dividing the sectional area A ⁿ determined by Equation 2 river width B (terrain conditions), it can be determined depth h.

Subsequently, the sand placement amount determination support device 1 obtains the flow rate Q and the flow velocity u of the flowing water at each position x at time t, based on the motion equation of the momentum conservation rule of the calculation formula data 15A (S206). Equation 4 shown below is an equation of motion of the momentum conservation law. Here, g represents a gravitational acceleration. z _s indicates a water level (vertical height). τ _bx represents a resistance force (sweeping force) in a flow direction per unit area. ρ represents the density of water. R represents the depth of the diameter (= cross-sectional area / junction), but may be the water depth h. Then, as shown in Equation 5, the flow velocity u is obtained by dividing the flow rate Q by the water depth h and the river width B.

Then, the sand placement determination support device 1 calculates the movement amount q _si of the earth and sand at each position x at time t based on the flow velocity u and the particle size d (terrain condition) (S207). Specifically, first, the frictional velocity u * is obtained from the flow velocity u by Equation 6. Here, i represents an energy gradient and is proportional to the flow velocity u. Let the proportionality coefficient be k. Next, the critical friction speed u * c is obtained from the particle diameter d by Expression 7 called Iwaki's Expression. Then, the movement amount q _{si of the} earth and sand is calculated from the friction speed u * and the limit friction speed u * c by Expression 8 called the Kamata Michigami Expression of the calculation expression data 15A. Here, s is the specific gravity of sand particles in water, and g is the gravitational acceleration. As for the Michigami Iwata ceremony, see, for example, P. of “Hydraulic Official Collection [1999 Edition]” (issued on November 25, 1999, Japan Society of Civil Engineers). 163 Refer to formula (2-4.32).

Furthermore, the sand placement determination support device 1 calculates the river bed height H at each time x at time t + Δt based on the movement amount q _{si of the} sediment (S208). S207 in determined time t, the movement amount _{q si} of sediment at each position x means that sediment of the amount _{q si} moves from position x after Δt to a position x + [Delta] x. Therefore, at position x after Δt, there is earth and sand going out to position x + Δx, while there is earth and sand coming in from position x−Δx. The value obtained by subtracting the movement amount q _{si of the} earth and sand is divided by the river width B and Δx and reflected in the current river bed height H (terrain condition), thereby obtaining the river bed height H at time t + Δt. By performing this calculation for each position x, a riverbed height distribution H (x) at time t + Δt is obtained and stored in the storage unit 15.

  When the calculation of the river bed height H is finished, the sand placement determination support device 1 adds Δt to the reference time t (S209). Then, it is determined whether or not the new time t is after the end time of the water discharge pattern acquired in S202 (S210). This end time may be the time when the water discharge ends in the dam, or the time when the water discharge reaches the downstream. If it is not after the end time (N in S210), the process returns to S204 to perform a calculation process for a new time t.

  If it is after the end time (Y in S210), the sand placement determination support device 1 ends the series of calculation processes from the start to the end of the water discharge, and obtains the final river bed height distribution H (x). It is displayed on the display unit 12 (S211). As a result, the simulation of earth and sand movement related to one amount of sand is completed. In addition, whenever it calculates the riverbed height H in S208, it displays on the display part 12, and the operator can see the state in the middle of earth and sand moving by flooding.

FIG. 4 is a diagram showing a simulation result of earth and sand movement when the amount of sand placed is 600 m ³ . FIGS. 4A, 4B, 4C, and 4D show the state of earth and sand at t = 0 hour, 2 hour, 5 hour, and 10 hour, respectively. In each graph, the horizontal axis indicates the distance [m] from the dam to the downstream, and the vertical axis indicates the height [m] from the river bed upstream of the dam. According to FIG. 4 (d), it can be seen that even at t = 10hour when the water discharge is completed, the earth and sand are rising about 150 m downstream from the dam. Therefore, it is considered that the amount of sand set at 600 m ³ is too large.

FIG. 5 is a diagram showing a simulation result of earth and sand movement when the amount of sand placed is 450 m ³ . 5A, 5B, 5C, and 5D show the state of earth and sand at t = 0 hour, 2 hour, 5 hour, and 10 hour, respectively. According to FIG. 5 (d), it can be seen that at t = 10hour when the water discharge is completed, earth and sand are scattered around 150 to 200 m downstream from the dam. Therefore, the amount of sand set at 450 m ³ is considered appropriate.

  As described above, the operator can determine and determine an appropriate amount of sand by referring to and evaluating the results of simulations relating to different amounts of sand.

  Although the embodiment of the present invention has been described above, the program executed by the processing unit 14 is recorded on a computer-readable recording medium in order to make each unit in the sand placement determination support device 1 shown in FIG. 1 function. The recorded program is read into a computer and executed to implement the sand placement determination support device according to the embodiment of the present invention. Note that the program may be provided to the computer via a network such as the Internet, or a semiconductor chip or the like in which the program is written may be incorporated in the computer.

  According to the embodiment of the present invention described above, the set amount determination support device 1 displays the state of the earth and sand moved by the flooding on the display unit 12 for each set amount of sand. An appropriate amount of sand can be determined by referring to and evaluating the situation after the amount of earth and sand has moved. Moreover, the operator can display the height of the riverbed at each position on the display unit 12 at a predetermined time from the start to the end of the water discharge, so that the operator can move the earth and sand by the water discharge. You can see the situation.

  Although the best mode for carrying out the present invention has been described above, the above embodiment is intended to facilitate understanding of the present invention and is not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and equivalents thereof are also included in the present invention.

It is a figure which shows the hardware constitutions of the amount setting support apparatus 1 and the data structure of the memory | storage part 15, (a) shows the hardware constitutions of the amount setting support apparatus 1 and (b) is the memory | storage part 15. The structure of stored data is shown. It is a flowchart which shows the simulation process by the sand placement amount determination assistance apparatus. It is a graph which shows an example of a flood pattern. 置砂weight is a diagram showing a simulation result of sediment transport in the case of 600m ^3, (a) is t = 0hour, (b) is t = 2hour, (c) is t = 5hour, (d) is t = The state of earth and sand at 10 hours is shown. It is a figure which shows the simulation result of the earth and sand movement in case the amount of sedimentation is 450 m < ³ >, (a) is t = 0hour, (b) is t = 2hour, (c) is t = 5hour, (d) is t = The state of earth and sand at 10 hours is shown. It is a figure which shows the mode of laying sand.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sedimentation amount determination support apparatus 14 Processing part 15 Storage part 15A Calculation formula data 15B Topographic condition data 15C Flooding pattern data

Claims (4)

A method for determining the amount of sand set used when determining the amount of sand settling from the upstream side to the downstream side of a dam of a hydroelectric power plant,
Calculation formula data representing each formula of Michigami's formula for the discrete equation of the law of conservation of mass as the basic formula of the flow, the equation of motion of the law of conservation of momentum as the basic formula of the flow, and the amount of scavenging sand,
The dam and downstream terrain condition data, including the amount of sand,
Water discharge pattern data indicating a temporal change in the flow rate related to the water discharge to flow the set sand downstream,
A computer including a storage unit that stores
For each predetermined time from the start to the end of the water discharge, each step of (1) to (5) is executed,
(1) A step of obtaining the flow rate of the water discharge from the water discharge pattern data (2) A cross-sectional area of the water flow at each position downstream from the dam by applying the discrete formula of the law of conservation of mass. And (3) calculating the flow rate and flow velocity of the flowing water at each position from the topographic condition data and the cross-sectional area by applying the equation of motion of the momentum conservation law. A step of calculating the amount of sediment movement at each position from the topographic condition data and the flow velocity by applying the Michigami formula (5) a step of calculating the bed height at each position from the amount of sediment movement Furthermore, a step of displaying a river bed height at each of the positions at the end of the water discharge is executed. It is a set amount determination support method of Claim 1,
The computer
For each predetermined time,
After calculating the river bed height at each position, the river bed height is displayed. A settling amount determination support device used for determining the amount of settling sand that is transferred from the upstream side to the downstream side of a dam of a hydroelectric power plant,
Calculation formula data representing each formula of Michigami's formula for the discrete equation of the law of conservation of mass as the basic formula of the flow, the equation of motion of the law of conservation of momentum as the basic formula of the flow, and the amount of scavenging sand,
Terrain condition data of the dam and downstream, including the amount of sand that has been moved from upstream to downstream of the dam of the hydroelectric power station,
Water discharge pattern data indicating a temporal change in the flow rate related to the water discharge to flow the set sand downstream,
A storage unit that stores
For each predetermined time between the start and end of the water discharge, each means of (1) to (5) is provided,
(1) Means for acquiring the flow rate of the water discharge from the water discharge pattern data (2) A cross-sectional area of the water flow at each position downstream from the dam by applying the discrete formula of the law of conservation of mass. And means for calculating water depth (3) means for calculating the flow rate and flow velocity of the flowing water at each position from the topographic condition data and the cross-sectional area by applying the equation of motion of the momentum conservation law (4) the Kamata (5) Means for calculating the river bed height at each position from the amount of movement of the earth and sand from the topographic condition data and the flow velocity by applying the Michigami formula. The sand placement determination support device further comprises means for displaying a riverbed height at each position at the end of the water discharge. A sand laying amount determination support device according to claim 3,
For each predetermined time,
After calculating the river bed height at each position, the river bed height is displayed.

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