Method for building clear water reservoir on multi-silt river

Abstract

The present application relates to a kind of method for building clear water reservoir on multi-silt river, comprising S1: analysis and calculation under a certain design flood standard design flood process;S2: analysis and determination of reservoir hub engineering construction scale and standard, sand trap engineering construction scale and standard, design flood and silt process of design flood and checking flood standard of reservoir design;S3: build clear water reservoir hub engineering;Sand trap and desilting engineering are built;Determine the layout of hydrology and water quality observation station, select observation station location and build observation station;S4: build internet of things information platform, collect hydrology and water quality observation station observation information, reservoir hub engineering, sand trap engineering all structures and its control gate valve sensing information, realize interconnection;S5: build riverway into reservoir flood and silt digital model, accurately simulate riverway water-sand migration evolution process, and automatically regulate reservoir storage process by internet of things information platform system.The present application achieves the purpose of storing clear water, blocking and discharging silt.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of water resource development and utilization, and particularly relates to a method for constructing a clear water reservoir on a river with much sediment. BACKGROUND

[0002] With the rapid development of economy and society and the rapid growth of population, people's unreasonable development and construction activities are increasingly frequent, which causes the water and soil loss in China to be increasingly serious. For the river with much sediment, the water quality of the water used cannot meet the needs of urban life, agricultural irrigation, aquaculture and other life production. In addition, for the river with water reservoirs, culverts and other water conservancy engineering facilities constructed on the river, the water flow carries a large amount of sediment, which will affect the use effect and service life of the engineering, the water reservoir capacity will be significantly reduced due to the sediment deposition of the reservoir, and the layout of the water diversion and sediment discharge structures, the output of the pumped storage power station and the economic benefit of the reservoir will be adversely affected. Further, if the outlet or inlet of the water conservancy engineering structure is blocked by the sediment and silt, the structure cannot be normally used, which will cause great harm to the engineering safety.

[0003] Many rivers in the world have much sediment in the water flow, especially the surface runoff formed by the rainstorm in the flood season, which has much more sediment in the water flow, and cannot meet the needs of people's production and life. The water resources cannot be fully utilized. When the reservoir is constructed on such a river, the service life of the reservoir is short due to the serious reservoir sedimentation, which is not economical. SUMMARY

[0004] The present application aims to provide a method for constructing a clear water reservoir on a river with much sediment, which uses the sediment retaining pool or front sediment retaining reservoir and sediment discharge engineering to divert the sediment, so as to store clear water and retain and discharge sediment, and meet the needs of water resource development.

[0005] The technical scheme of the present application is as follows:

[0006] A method for constructing a clear water reservoir on a river with much sediment,

[0007] S1: determining the position of the clear water reservoir to be constructed, collecting and analyzing the measured hydrological data of the upstream river to calculate the design flood process under a certain design flood standard;

[0008] S2: analyzing and determining the construction scale and standard of the reservoir hub engineering, the construction scale and standard of the sediment retaining pool engineering, and the design flood and sediment process of the design and checking flood standard;

[0009] S3: constructing the clear water reservoir hub engineering, including the river dam, spillway and sediment discharge tunnel; constructing the sediment retaining pool and sediment discharge engineering, including the sediment retaining and water rolling dam, sediment discharge tunnel and clear water water conveying tunnel; determining the layout of the hydrological and water quality observation station network, selecting the observation station position and constructing the observation station;

[0010] S4: Construct an Internet of Things (IoT) information platform to collect observation information from hydrological and water quality observation stations, as well as sensing information from all structures and control gates and valves of reservoir hub projects and sediment trap projects, to achieve interconnection and interoperability of IoT;

[0011] S5: Construct digital models of river inflow floods and sediment to accurately simulate the evolution of water-sediment transport in the river and automatically regulate the reservoir's water storage process through an Internet of Things (IoT) information platform system.

[0012] Preferably, S1 collects previously measured hydrological data of the river channel to determine the construction scale, design and verification standards of the reservoir hub project, the construction scale and design standards of the sediment trap project, and to reasonably determine the design flood process of the inflow design and verification flood standards; the measured hydrological data are measured data for more than 30 consecutive years.

[0013] Preferably, the specific method for S1 analysis to calculate the design flood process under a certain design flood standard is as follows:

[0014] Assume the statistical parameters of the frequency curve are taken as the mean. Coefficient of variation C v and skewness coefficient C s This indicates that the method of moments is used to estimate the initial values ​​of the parameters; for an n-year continuous series, the formula for calculating each statistical parameter using the rectangular method is:

[0015]

[0016]

[0017]

[0018] The frequency curve adopts the Pearson Type III curve. The statistical parameters are adjusted using the Pearson Type III curve for fitting. The optimal statistical parameters for the frequency curve are selected using the fitting method.

[0019] By performing frequency analysis and calculation on the flood peak flow and time period flood volume series, the design flood peak and time period flood volume results at different frequencies are obtained; thus, the design flood process line of Qingshui Reservoir is obtained.

[0020] Preferably, the dam in S3 is used to impound clear water, the spillway is used to discharge excess impounded water, and the sand discharge tunnel is used to discharge silt accumulated at the bottom of the clear water reservoir.

[0021] Preferably, the sand-blocking weir described in S3 is used to intercept floods with excessive sediment content in the river channel, preventing bottom sediment, especially bedload sediment, from entering the clear water reservoir; when encountering a large flood, the floodwater enters the reservoir through overflow from the top of the sand-blocking weir; the sand-transporting tunnel is used to discharge floods with excessive sediment content and bottom sediment, especially bedload sediment.

[0022] The clear water conveying tunnel is built in the mountain under the sand blocking and water rolling dam or on both sides of the sand blocking and water rolling dam, and is used for conveying the river water with no exceeding standard sand content directly into the clear water reservoir for storage.

[0023] Preferably, in S3, the hydrological and water quality observation station network is determined, the observation station position is selected, and the observation station is built to realize real-time monitoring of water level, flow, flow rate, and sediment content water quality indicators.

[0024] Preferably, in S4, the Internet of Things information platform is constructed, the sensing information of all structures of the clear water reservoir hub project and the sand blocking pool project and the control gate valve thereof is collected, and the collected sensing information is transmitted to the Internet of Things information platform to realize interconnection.

[0025] Preferably, S5 comprises the following specific steps: when the sand content water quality indicator of the river water at the water quality control section of the reservoir is less than the control threshold value, the clear water conveying tunnel control gate valve is automatically opened, so that the river water directly enters the clear water reservoir for storage; when the sand content water quality indicator of the river water at the water quality control section of the reservoir is greater than the control threshold value, the clear water conveying tunnel control gate valve is automatically closed, and the sand conveying tunnel control gate valve is automatically opened, so that the river water with sand content exceeding the threshold value and the sand thereof are discharged to the downstream of the clear water reservoir dam through the sand conveying tunnel, so as to achieve the purpose of storing clear water and discharging muddy water.

[0026] Preferably, in S5, the computational fluid dynamics theory is used to establish and accurately simulate the river water-sand migration and evolution process, and the reservoir storage process is automatically regulated and controlled through the Internet of Things information platform.

[0027] Preferably, the computational fluid dynamics theory is used to establish the river water-sand migration and evolution process, and the following methods can be used:

[0028] (1) Flow control equation of flow field

[0029]

[0030]

[0031]

[0032]

[0033] In the formula, u i represents the component of velocity in the i direction, u' i represents the fluctuating velocity in the i direction; p is the pressure; S ij is the strain rate tensor; u' i u' j is the Reynolds stress tensor; p is the fluid density; v is the dynamic viscosity; v t is the turbulent viscosity; k is the turbulent kinetic energy; and d ij is the Kronecker symbol (dij = 1, i = j; δ ij = 0, i ≠ j);

[0034] (2) RNG k-ε equation

[0035]

[0036]

[0037] where k is the turbulent kinetic energy, ε is the turbulent kinetic energy dissipation rate, μ t is the eddy viscosity, τ ij is the Reynolds stress, model constants Cμ= 0.085, C1ε= 1.42, C2ε= 1.68, σk=σε= 0.7179;

[0038] (3) Sediment transport model

[0039] Flow shear stress:

[0040] Critical shear stress for incipient motion of sediment:

[0041] Hills number:

[0042] Critical Hills number:

[0043] where τ is the flow shear stress, τc is the critical shear stress for incipient motion of sediment, θ is the Hills number, θc is the critical Hills number, U * is the friction velocity, U *c is the critical friction velocity, ρ and ρ s are the densities of water and sediment, respectively, and d is the average grain size of sediment.

[0044] The formula for the sediment transport rate per unit width of bed load is:

[0045]

[0046] where q b is the sediment transport rate per unit width of bed load, u b is the average transport velocity of bed load, and p is the probability of sediment incipient motion. For soil tests of actual engineering geology, u b and p can be obtained according to the above formula, and q b can be solved.

[0047]

[0048] The kinetic friction force is:

[0049] In the formula: f D This refers to kinetic friction.

[0050] f D =f D By combining (10), we get

[0051]

[0052] make but

[0053] In the formula: aU * For the velocity of water flow carrying bedload, when close to the sand bed, a = 6–10; C D This is the thrust coefficient. When θ0 = 0, u b =0, θ0 is equivalent to the stopping relative shear stress, which should be less than the critical relative shear stress θ. c Therefore, equation (18) can be written as

[0054]

[0055] The sum of the critical shear stress of sediment and the shear stress experienced by moving particles is the shear stress, i.e.

[0056]

[0057] In the formula: n is the total number of sediment particles, and the total number of sediment particles per unit area of ​​riverbed. The relationship with p is: Combining (12) and (13), the activation probability of the sediment particles on the bed surface is obtained as follows:

[0058]

[0059] Bedload transport formula:

[0060]

[0061] Equation (19) is the sediment movement model used.

[0062] The beneficial effects of this invention are:

[0063] This invention discloses a method for constructing a clear water reservoir on a sediment-laden river channel. The method involves collecting historical hydrological and sediment data from the river channel to determine the construction scale and design / verification standards of the reservoir's key engineering components, sediment traps, and sediment discharge works. An Internet of Things (IoT) information system is then established to determine the layout of a hydrological and water quality monitoring network. Real-time monitoring of water level, flow rate, flow velocity, and sediment content, among other water quality indicators, enables automatic regulation of the reservoir's water storage process. This invention achieves the goals of storing clear water and intercepting sediment, thus meeting the needs of water resource development. Attached Figure Description

[0064] To more clearly illustrate the embodiments or technical solutions, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0065] Figure 1 A flowchart of a method for constructing a clear water reservoir on a riverbed with high sediment content, provided by the present invention;

[0066] Figure 2 This is a schematic diagram of a typical layout of a Qingshui Reservoir project according to an embodiment of the present invention;

[0067] Figure 3 This is a line diagram of the flood inflow process according to an embodiment of the present invention.

[0068] In the diagram: 1. Qingshui Reservoir; 1.1 Dam, 1.2 Spillway, 1.3 Desilting Tunnel, 1.4 Desilting Tunnel Control Gate;

[0069] 2. Sediment retention basin; 2.1 Sediment retention weir; 2.2 Sediment conveying tunnel; 2.3 Sediment conveying tunnel control gate; 2.4 Clear water conveying tunnel; 2.5 Clear water conveying tunnel control gate;

[0070] 3. Water quality / hydrological observation station;

[0071] 4. Internet of Things (IoT) information platform. Detailed Implementation

[0072] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0073] like Figure 1 As shown, this invention provides a design method for constructing a clear water reservoir on a river channel with high sediment content, which includes the following steps:

[0074] S1: Determine the location of the clear water reservoir, collect and analyze the measured hydrological data of the upstream river channel, and calculate the typical design flood process under a certain design flood standard. The specific statistical analysis method (not limited to) is as follows:

[0075] Let the statistical parameters of the frequency curve be the mean Coefficient of variation C v And the skewness coefficient C s Indicates that the initial value of the parameter is estimated by the moment method; for n consecutive series, the formula for calculating each statistical parameter by the moment method is:

[0076]

[0077]

[0078]

[0079] The frequency curve is a Pearson III curve, and the statistical parameters are adjusted by the Pearson III curve. The optimal statistical parameters of the frequency curve are selected by the fitting method;

[0080] Through frequency analysis and calculation of the flood peak flow and period flood volume series, the design flood peak and period flood volume results of different frequencies are obtained; thus the typical design flood hydrograph under a certain standard condition of the clear water reservoir is obtained.

[0081] S2: Analyze and determine the construction scale / standard of the reservoir hub project, the construction scale / standard of the sand trap project, and the design flood / sediment process of the design / calibration flood standard.

[0082] S3: Build the clear water reservoir hub project, including the river dam, spillway, sand discharge tunnel, etc.; build the sand trap and sand discharge project, including the sand trap (water rolling) dam, sand discharge tunnel, clear water discharge tunnel, etc.; determine the layout of the hydrological / water quality observation station network, select the observation station location and build the observation station.

[0083] S4: Build an Internet of Things information platform, collect hydrological / water quality observation information, reservoir hub project, sand trap project and all structures and their control gate valve (door) sensing information, and realize interconnection. The hydrological / water quality observation information record is shown in Table 1 (not limited to), and the sensing information record of the reservoir hub project, sand trap project and all structures and their control gate valve (door) is shown in Table 2 (not limited to):

[0084] Table 1 Hydrological / Water Quality Observation Information

[0085]

[0086] Table 2 Building Control Gate Valve (Door) Sensing Information

[0087]

[0088] When the water quality index such as the sediment concentration of the river water (the water quality control section into the reservoir) is less than (not exceeding) the control threshold value, the clear water tunnel control gate valve (door) is automatically opened, so that the river water directly enters the clear water reservoir for storage; when the water quality index such as the sediment concentration of the river water (the water quality control section into the reservoir) is greater than (exceeding) the control threshold value, the clear water tunnel control gate valve (door) is automatically closed, and the sediment tunnel control gate valve (door) is automatically opened at the same time, so that the river water and its sediment with sediment concentration exceeding the threshold value are discharged to the downstream of the dam through the sediment tunnel, so as to achieve the purpose of storing clear water and discharging muddy water.

[0089] S5: Constructing a river water / sediment digital model into the reservoir, accurately simulating the river water-sediment transport and evolution process, and automatically regulating the reservoir water storage process through the Internet of Things information platform system.

[0090] The river water / sediment digital model into the reservoir is built, and the computational fluid dynamics theory is used to establish the river water-sediment transport process, which can be specifically implemented by the following methods (not limited to):

[0091] (1) Flow control equation of flow field

[0092]

[0093]

[0094]

[0095]

[0096] In the formula: u i represents the component of velocity in the i direction, u′ i represents the fluctuating velocity in the i direction; p is the pressure; S ij is the strain rate tensor; u′ i u′ j is the Reynolds stress tensor; ρ is the fluid density; v is the dynamic viscosity; v t is the turbulent viscosity; k is the turbulent kinetic energy; δ ij is the Kronecker symbol (δ ij =1, i=j; δ ij =0, i≠j).

[0097] (2) RNG k-ε equation

[0098]

[0099]

[0100] In the formula: k is the turbulent kinetic energy, ε is the turbulent kinetic energy dissipation, μ t is the eddy viscosity coefficient, τ ij is the Reynolds stress, Model constants Cμ=0.085, C1ε=1.42, C2ε=1.68, σk=σε=0.7179.

[0101] (3) Sediment transport model

[0102] Shear stress of water flow:

[0103] Critical shear stress of sediment incipient motion:

[0104] Hills number:

[0105] Critical Hills number:

[0106] Where: τ is the shear stress of water flow, τc is the critical shear stress of sediment incipient motion, θ is the Hills number, θc is the critical Hills number, U * is the friction velocity, U *c is the critical friction velocity, ρ and ρ s are the densities of water and sediment respectively, and d is the average grain size of sediment.

[0107] The formula of sediment transport rate per unit width is:

[0108]

[0109] Where: q b is the sediment transport rate per unit width; u b is the average transport velocity of sediment; and p is the probability of sediment incipient motion. For soil tests of actual engineering geology, u b and p can be obtained according to the above formula, and then q b can be solved.

[0110]

[0111] Dynamic friction force is:

[0112] Where: f D is the dynamic friction force.

[0113] F D = f D and parallel to equation (10), we get

[0114]

[0115] Let then

[0116] where a = 6-10 when the flow is close to the bed, and C = 0.5-1.0 * is the flow velocity of the bed load, and u = 0 when θ0= 0, θ0corresponds to the relative shear stress at which the sediment bed is stationary, and should be less than the critical relative shear stress θ D b = 0, θ0corresponds to the relative shear stress at which the sediment bed is stationary, and should be less than the critical relative shear stress θ c Thus, equation (18) can be written as

[0117]

[0118] The sum of the critical shear stress of the sediment and the shear stress experienced by the moving particles is the shear stress, i.e.

[0119]

[0120] where n is the total number of sediment particles, and the total number of sediment particles per unit area of the river bed is The relationship between n and p is: By combining equations (12) and (13), the probability of the initiation of the sediment particles on the bed surface is obtained as

[0121]

[0122] Bed load transport formula:

[0123]

[0124] Equation (19) is the sediment transport model used in this paper.

[0125] Application example

[0126] As Figure 2 ​As shown, when a clear water reservoir is built on a multi-sediment river, first, the dam site position of the clear water reservoir is determined according to topography, geology and other factors, the river dam 1.1, spillway 1.2 and desilting tunnel 1.3 of the clear water reservoir 1 are arranged according to the engineering task and scale of the clear water reservoir, and the desilting tunnel control gate 1.4 is arranged at the inlet of the desilting tunnel 1.3. Then, according to the scale of the clear water reservoir 1, the desilting pool 2 position is selected on the upstream of the clear water reservoir 1, the scale of the desilting roller dam 2.1 is determined according to the river hydrology and sediment conditions, the sand conveying tunnel 2.2 is arranged in the upstream mountain body of the desilting roller dam 2.1 and the sand conveying tunnel control gate 2.3 is arranged at the inlet, the upstream sediment is discharged to the downstream of the clear water reservoir through the sand conveying tunnel 2.2, at the same time, the clear water tunnel 2.4 is arranged on the dam body of the desilting roller dam 2.1 and the clear water conveying tunnel control gate 2.5 is arranged at the inlet, so that the clear water is discharged to the reservoir area of the clear water reservoir through the clear water conveying tunnel 2.4. At the same time, the water quality / hydrology observation station 3 is arranged on the upstream of the desilting pool 2, and the Internet of Things information platform 4 is constructed, the collected sensing information is transmitted to the Internet of Things information platform 4, and the Internet of Things interconnection is realized. Finally, the digital model of the incoming flood / sediment is constructed, the water-sediment migration and evolution process of the river channel is simulated, and the reservoir storage process is automatically controlled. Finally, when the upstream water comes, the water quality / hydrology observation station uploads the monitoring data to the Internet of Things information platform, the opening and closing of the sand conveying tunnel control gate 2.3 and the clear water conveying tunnel control gate 2.5 of the desilting roller dam 2.1 are controlled according to the digital model simulation calculation, and the goal of building the clear water reservoir is realized.

[0127] The control basin area above the reservoir dam is 24341km 2 It is located in the middle latitude of the east of Eurasia continent, and the characteristics of continental monsoon are obvious. The winter is long, dry and cold, and the northwest wind prevails. The summer is short, hot and rainy, and the spring and autumn are windy and sandy. The cold and warm change is significant, and the seasonality is strong. According to the data of the local weather station: the annual average temperature in the basin is 6-8℃, the average temperature in January is-10℃ to-13℃, the average temperature in July is 20-23℃, the highest and lowest temperature is 37℃ and-35℃ respectively, the frost-free period decreases from east to west, the basin area is 120-170d, the mountain area is only about 100d, and the freezing period is 4 months or even longer. The annual average precipitation is only about 400mm, the annual water evaporation is 900-1000mm, and 70-80% of the precipitation is concentrated in the flood season from June to September, and most of it is in the form of rainstorm, which is mostly local rainstorm.

[0128] The vegetation in the project area is poor, except for some alpine mountainous areas, the loess hilly and soil mountainous area is widely distributed, and the gullies are crisscrossed. The soil is basically loess and sandy loam, with loose structure, strong water permeability, poor land, and serious soil erosion, which causes the reservoir to have high sediment content. In order to ensure that the sediment content of the reservoir can meet the requirements of the pumped storage power station, a sand retaining facility, i.e. a front sand retaining reservoir, is built in the upstream of the dam site of the clear water reservoir, and a flood and sediment discharge tunnel is built in the right bank mountain of the upstream of the dam site of the sand retaining reservoir. The sediment is guided into the downstream river channel of the clear water reservoir through the flood and sediment discharge tunnel, so as to ensure that the bed load sediment and the high-sediment-content river bottom flood do not enter the downstream clear water reservoir, so as to achieve the purpose of storing clear water and discharging muddy water to meet the water quality requirements of power generation, production and living. The specific implementation method of the present application is as follows:

[0129] (1) Collecting river hydrological data

[0130] According to the location of the clear water reservoir, the upstream hydrological station with a longer hydrological observation data length (72 years) is selected, the flood and runoff measured process is collected, the natural annual runoff of the clear water reservoir under different frequency conditions and the design flood process line are calculated by using the aforementioned mathematical statistics method, the sediment measured process of the hydrological station is collected, and the average annual sediment amount of the river channel is analyzed and calculated as 1.86 million m3. The reservoir flood process line is shown in Figure 3 , the correlation coefficient of the flood and sediment transport rate is 0.8, the correlation is strong, and the reservoir sediment process is basically consistent with the reservoir flood process.

[0131] (2) Determining the engineering scale / standard

[0132] 1) Scale determination

[0133] The clear water required for the pumped storage lower reservoir should meet the water requirement of the pumped storage power station and the local production and living water requirement, i.e. 32 million m 3 , as the control condition.

[0134] 2) Analysis of sedimentation and determination of characteristic water level

[0135] a) Sand retaining pool: according to the aforementioned sediment analysis, the average annual sediment amount of the sand retaining pool is 1.86 million m3. According to the dispatching mode of the sand retaining pool and the arrangement of the reservoir sediment discharge and flood discharge facilities, the sand retaining dam is an overflow rolling water dam, i.e. sand retaining (rolling water) dam, and the control operation condition is:

[0136] Condition one: when the river water is less than or equal to the 10-year flood, the sand retaining (rolling water) dam does not overflow

[0137] When the river water (water quality control section into the reservoir) contains less than (not over standard) threshold value of water quality indicators, the clear water tunnel control gate valve (door) is automatically opened to make the river water directly into the clear water storage; When the river water (water quality control section into the reservoir) contains more than (over standard) threshold value of water quality indicators, the clear water tunnel control gate valve (door) is automatically closed to make the water storage and sediment deposition before the sand (water) dam. When the water quality meets the requirements (usually the surface water), the clear water tunnel control gate valve (door) is opened again; The river bed load sediment and high sediment content water generated by flood in 10 years are discharged through the automatic opening of the flood discharge and sediment discharge tunnel control gate valve (door) to the downstream of the clear water storage reservoir.

[0138] Condition two: when the river water exceeds the 10-year flood, the sand dam weir crest overflows

[0139] At this time, according to the river water (water quality control section into the reservoir) contains, the weir crest overflow and the flood discharge of the flood discharge and sediment discharge tunnel are controlled through the Internet of Things information platform. When the river water (water quality control section into the reservoir) contains less than (not over standard) threshold value of water quality indicators, the clear water tunnel control gate valve (door) is fully opened, the clear water tunnel overflows, and the water entering the clear water storage is connected with the weir crest overflow; When the river water (water quality control section into the reservoir) contains more than (over standard) threshold value of water quality indicators, the clear water tunnel control gate valve (door) is closed, and the flood discharge and sediment discharge tunnel control gate valve (door) is automatically opened at the same time, the river water with sand content exceeding the threshold value and its sediment are discharged through the flood discharge and sediment discharge tunnel to the downstream of the clear water storage reservoir. At this time, the sediment content (all the upper water of the river flow) of the water flow through the weir crest of the sand dam (water) is significantly reduced.

[0140] According to the above control operation mode, it is analyzed that:

[0141] Sand dam (water): weir crest elevation 679.10m (flat 10-year flood level), weir width 6m, maximum dam height 17.5m; The slurry stone water roller dam is adopted.

[0142] Flood discharge and sediment discharge tunnel: aperture size 7.5m x 7.5m (width x height);

[0143] Clear water tunnel: aperture size 2m x 2m (width x height);

[0144] b) Clear water reservoir: the sand content of the clear water reservoir is mainly the suspended sediment of the water flow into the reservoir, and the average annual accumulation of the clear water reservoir is only 136,000m3. According to the need of the reservoir capacity of the clear water reservoir, the dead water level of the clear water reservoir is determined as 660.00m, the dam top elevation of the sand dam is 702.5m, the dam length is 223m, the dam height is 7m, and the concrete face dam is adopted.

[0145] Spillway: weir elevation 690 m, weir width 12 m.

[0146] (3) Constructing the Internet of Things information platform

[0147] The present application plans to build 55 water quality / hydrology observation sites in the upstream watershed of the reservoir, which meets the requirements of monitoring the hydrology and sediment process of the river channel in each period. Through the construction of the Internet of Things information platform, the observation information of the hydrology / water quality observation station, the sensing information of all structures such as the reservoir hub project and the sand retaining pool project and their control gate valves (doors) are collected, and the interconnection of the Internet of Things is realized.

[0148] (4) Constructing a three-dimensional hydrodynamic model of the river channel

[0149] A three-dimensional hydrodynamic digital model is constructed by using the aforementioned computational fluid dynamics theory, and the hydrology and sediment process in each period observed by the aforementioned river hydrology / sediment observation station is used as the input process of the three-dimensional hydrodynamic model, so as to construct a river channel flood / sediment digital model, accurately simulate the water-sediment migration and evolution process of the river channel, and automatically regulate the reservoir storage process through the Internet of Things information platform system.

[0150] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with a preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content to obtain equivalent embodiments with equivalent changes, without departing from the scope of the technical solution of the present application. Any modification, equivalent change and modification of the above embodiments made in accordance with the technical essence of the present application are still within the scope of the technical solution of the present application.

Claims

1. A method for building a clear water reservoir on a multi-silt river channel, characterized in that, S1: determining the location of the clear water reservoir, collecting and analyzing the measured hydrological data of the upstream river channel to calculate the design flood process under a certain design flood standard; S2: analyzing and determining the construction scale and standard of the reservoir hub project, the construction scale and standard of the sand retaining pool project, and the design flood and silt process of the design and checking flood standard; S3: building the clear water reservoir hub project, including the river dam, spillway, and sand discharge tunnel; building the sand retaining pool and sand discharge project, including the sand retaining and rolling dam, sand conveying tunnel, and clear water conveying tunnel; determining the layout of the hydrological and water quality observation station network, selecting the observation station location, and building the observation station; S4: building an Internet of Things information platform, collecting the observation information of the hydrological and water quality observation stations, the sensing information of all structures of the reservoir hub project and the sand retaining pool project, and their control gates and valves, and realizing the interconnection of the Internet of Things; S5: building a river channel reservoir flood and silt digital model, accurately simulating the water-silt migration and evolution process of the river channel, and automatically regulating the reservoir storage process through the Internet of Things information platform system.

2. A method of constructing a clear water reservoir on a multi-silt river channel according to claim 1, characterized in that, S1 collects the past measured hydrological data of the river channel to determine the construction scale of the reservoir hub project, the design and checking standard, the construction scale of the sand retaining pool project, the design standard, and the design flood process of the design and checking flood standard.

3. A method of constructing a clear water reservoir on a multi-silt river channel according to claim 1, characterized in that, The specific method of S1 analyzing and calculating the design flood process under a certain design flood standard is as follows: The statistical parameters of the frequency curve are taken as the mean The coefficient of variation C v And the coefficient of skewness C s Indicates that the initial values of the parameters are estimated by the method of moments; for a continuous series of n years, the formula for calculating each statistical parameter by the method of moments is: The frequency curve adopts the Pearson III type curve, the statistical parameters are adjusted using the Pearson III type curve, and the statistical parameters of the optimal frequency curve are selected using the curve fitting method; The design flood peak and period flood volume results of different frequencies are obtained by frequency analysis and calculation of the flood peak flow and period flood volume series, so as to obtain the clear water reservoir design flood process line.

4. A method of constructing a clear water reservoir on a multi-silt river channel according to claim 1, characterized in that, The river dam in S3 is used to retain clear water, the spillway is used to discharge excess water storage, and the sand discharge tunnel is used to discharge the silt accumulated at the bottom of the clear water reservoir.

5. A method of constructing a clear water reservoir on a multi-silt river channel according to claim 1, characterized in that, The sand retaining and rolling dam in S3 is used to intercept the flood with excessive sand content in the river channel and prevent the bottom silt of the flood from entering the clear water reservoir; when encountering a flood, the flood enters the reservoir through the overflow of the top of the sand retaining and rolling dam; the sand conveying tunnel is used to discharge the flood with excessive sand content and the bottom silt of the flood; the clear water conveying tunnel is built in the lower part of the sand retaining and rolling dam or the mountain on both sides of the sand retaining and rolling dam, and is used to convey the river water with non-excessive sand content directly into the clear water reservoir for storage.

6. A method of constructing a clear water reservoir on a multi-silt river channel according to claim 1, wherein In S3, the layout of the hydrological and water quality observation station network is determined, the observation station location is selected, and the observation station is built to realize real-time monitoring of water level, flow rate, flow velocity, and silt content water quality indicators.

7. A method of constructing a clear water reservoir on a multi-silt river channel according to claim 1, wherein In S4, the Internet of Things information platform is built to collect the sensing information of all structures of the clear water reservoir hub project and the sand retaining pool project and their control gates and valves, and to transmit the collected sensing information to the Internet of Things information platform to realize the interconnection of the Internet of Things.

8. A method of constructing a clear water reservoir on a multi-silt river channel according to claim 1, characterized in that, S5 is specifically: when the river water into the reservoir water quality control section of the sediment content water quality index is less than the control threshold, automatically open the clear water tunnel control gate valve, so that the river water directly into the clear water storage; when the river water into the reservoir water quality control section of the sediment content water quality index is greater than the control threshold, automatically close the clear water tunnel control gate valve, and automatically open the sand tunnel control gate valve, the sediment content of the river water and its sediment through the sand tunnel discharge to the clear water reservoir dam downstream, in order to achieve the purpose of storing clear and discharging muddy.

9. The method of claim 8, wherein the method further comprises: S5 adopts the theory of computational fluid dynamics to establish and accurately simulate the river water-sand transport and evolution process, and automatically controls the reservoir storage process through the Internet of Things information platform.

10. The method of claim 9, wherein the method is characterized by: The theory of computational fluid dynamics is used to establish the river water-sand transport and evolution process, and the specific method is as follows: (1) Flow control equation where: u i represents the component of velocity in the i direction, u′ i represents the fluctuating velocity in the i direction; p is pressure; S ij is the rate of strain tensor; u′ i u′ j is the Reynolds stress tensor; p is fluid density; v is dynamic viscosity; v t is the turbulent viscosity; k is the turbulent kinetic energy; d ij is the Kronecker delta (d ij = 1, i = j; d ij = 0, i ≠ j); (2) RNG k-ε equation where k is the turbulent kinetic energy, ε is the turbulent kinetic energy dissipation rate, μ t is the eddy viscosity, τ ij is the Reynolds stress, Model constants Cμ= 0.085, C1ε= 1.42, C2ε= 1.68, σk=σε= 0.7179; (3) Sediment transport model Water flow shear stress: Critical shear stress for incipient motion of sediment: Hilbert number: Critical Hill number: where τ is the shear stress of the flow, τ c is the critical shear stress for incipient motion of sediment, θ is the Shields number, θ c is the critical Shields number, U* is the friction velocity, U* c is the critical friction velocity, ρ and ρ s are the densities of the flow and sediment, respectively, and d is the mean grain size of the sediment. The formula for unit width of sediment transport rate is: where q b is the unit width sediment transport rate; u b is the average transport velocity of the sediment; p is the threshold probability of the sediment; for the soil test of the actual engineering geological conditions, u b and p can be obtained according to the above formula, and then q b can be solved. The kinetic friction force is: wherein: f D F is the dynamic friction force; F D = f D and (10) gives Let Then In the formula: aU * For the velocity of water flow carrying bedload, when close to the sand bed, a = 6–10; C D U is the thrust coefficient; when θ0 = 0, u b =0, θ0 is equivalent to the stopping relative shear stress, which is less than the critical relative shear stress θ. c Therefore, equation (18) can be written as The sum of the critical shear stress of the sediment and the shear stress of the moving particles is the shear stress, that is where n is the total number of sediment particles, and the total number of sediment particles per unit area of riverbed The relationship with p is: By combining (12) and (13), the probability of the initiation of the sediment particles on the riverbed is The formula for sediment transport is: Equation (19) is the sediment transport model adopted.

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