A method for sediment control in water conservancy projects on sandy rivers

Abstract

This invention provides a method for sediment control in water conservancy projects on sediment-laden rivers, comprising: collecting runoff and sediment data from inflow hydrological stations to analyze the characteristics of inflow water and sediment and the properties of floodwater and sediment; collecting reservoir operation data and reservoir sedimentation data to analyze the sedimentation process and distribution in the reservoir area, thereby obtaining the reservoir sediment discharge pattern; collecting reservoir design data to determine the scale of reservoir dredging and sediment control targets; formulating reservoir sediment discharge operation methods, and combining measured water and sediment data to determine the changes in scouring and sedimentation in the reservoir area and the scouring efficiency, thereby analyzing the longitudinal and transverse cross-sectional morphology, channel morphology, channel size, and scouring range of the reservoir to determine the effects of hydraulic dredging and mechanical dredging; determining the location for pushing sediment into the channel and the annual amount of sediment pushed in, and formulating a reservoir sediment control scheme based on hydraulic regulation and mechanical pushing of sediment into the channel to control dredging of the reservoir. The invention proposes a technology based on hydraulic scouring supplemented by mechanical dredging, which facilitates the efficient treatment of engineering sediment.

Description

Technical Field

[0001] This invention relates to the field of water conservancy engineering technology, and in particular to a method for sediment control in water conservancy projects on sandy rivers. Background Technology

[0002] Rivers with high sediment loads are characterized by large sediment transport volumes and high sediment concentrations. Taking the Yellow River basin as an example, due to its passage through the Loess Plateau, where soil erosion is severe and the ecological environment is fragile, the massive amounts of sediment produced by erosion during heavy rains make it the river with the largest sediment transport volume and highest sediment concentration in the world. The measured multi-year average runoff at the Tongguan Hydrological Station on the Yellow River from 1919 to 2020 was 36.43 billion m³. 3 The sediment transport volume was 1.11 billion tons, with an average sediment concentration of 30.5 kg / m³. 3 The measured maximum sand content was 911 kg / m³. 3 (In 1977), tributaries on both banks of the river from Hekou Town to Sanmenxia frequently experienced water levels of 1000–1700 kg / m³. 3 High-sediment-laden floods are a serious problem. Sedimentation has led to severe siltation in reservoirs of major water conservancy projects within the basin. According to a 2012 survey by the Ministry of Water Resources, the average siltation rate of reservoirs in Shanxi and Shaanxi provinces reached 34%, with some reservoirs exceeding 80%. Sedimentation in reservoirs encroaches on two fronts: firstly, it reduces the flood control and water utilization capacity of reservoirs, affecting their normal functions in flood control, irrigation, water supply, and power generation; secondly, it clogs spillway structures, impacting the safe operation of dams. Future construction of new reservoirs will inevitably face challenges such as resettlement, land occupation, and high costs. Therefore, controlling siltation in reservoirs, implementing reservoir dredging, tapping into water storage potential, and fully utilizing reservoir functions are effective ways to alleviate the water resource crisis.

[0003] Currently, reservoir dredging methods mainly include hydraulic dredging and mechanical dredging. Hydraulic dredging relies on the power of water flow to flush silt out of the reservoir, with common methods including spillway flushing, flood discharge and sediment removal, and density flow sediment removal. Mechanical dredging uses mechanical equipment to directly excavate and transport silt from the reservoir to the outside, with common equipment including dredgers, mud pumps or pneumatic pumps, self-priming pipeline sediment removal, and mechanical dredging. Each dredging method has its advantages and disadvantages and is suitable for different environments. Mechanical dredging is flexible and consumes less water, but it has a small silt removal capacity, high cost, and causes significant disturbance to the reservoir bottom sediment, making it suitable for small and medium-sized reservoirs. Hydraulic dredging has high requirements for discharge and sediment removal facilities and water flow conditions, and its operation may affect the normal operation of the reservoir, but it can remove a large amount of silt, making it suitable for large and medium-sized reservoirs. For reservoirs in sandy rivers, the amount of siltation is generally large, and most are located in arid and water-scarce areas. Relying solely on mechanical dredging is costly and the treated dredged sand is difficult, making it hard to restore reservoir capacity and control siltation. Hydraulic dredging is also limited by the layout of key engineering projects, low water inflow, and the normal operation of the reservoir, making it difficult to restore capacity and control siltation in the short term. For example, the Bajiazui Reservoir in Qingyang City, Gansu Province, belongs to the Puhe River, a tributary of the Jinghe River, with an average annual inflow of 130 million cubic meters per second. 3 The sediment transport volume was 28.48 million tons, and the average annual sediment concentration was 218 kg / m³. 3 The average sediment content during the main flood season was 373 kg / m³. 3 Average annual inflow is 1.90 m³. 3 / s, with an average flow rate of 4.74m³ / s during the main flood season from July to August. 3 The reservoir experiences only one or two floods a year. Completed in July 1962, it has a capacity of 257 million cubic meters. 3 After multiple heightening and reinforcements, the total reservoir capacity is now 540 million cubic meters. 3 It is a large (2) type reservoir, a comprehensive reservoir mainly for flood control and water supply, while also serving irrigation and power generation. Although the reservoir's discharge capacity is sufficient, due to the recent decrease in the probability of floods, the contradiction between water supply and sediment discharge during the flood season is prominent, the reservoir has few opportunities for sediment discharge, and sediment accumulation is serious. As of October 2019, the reservoir's cumulative sediment accumulation has reached 411 million cubic meters. 3 An average annual siltation of 6.85 million cubic meters 3 As of October 2019, the reservoir's remaining total capacity was 137 million cubic meters. 3 The remaining reservoir capacity is only 5.39 million cubic meters. 3 The designed regulating capacity is 20.3 million cubic meters. 3 26.5%; flood control capacity remaining is only 136.6 million cubic meters. 3 It is close to the designed flood control capacity of 130.4 million cubic meters. 3The reservoir's capacity is insufficient to meet regulation requirements, and the reduced water volume makes it difficult to dilute the sulfate entering the reservoir, leading to excessive sulfate concentrations in the reservoir area and threatening the city's water supply security. Therefore, the need for dredging the Bajiazui Reservoir is urgent. However, due to the large volume of dredging required, and with the recent decrease in the amount and frequency of floodwater entering the reservoir, relying solely on hydraulic or mechanical dredging will be insufficient to restore reservoir capacity and control siltation in the short term.

[0004] With the increasing impact of human activities in recent years, the water and sediment production environment of river basins has undergone significant changes, leading to a prominent contradiction between economic and social water use and hydraulic sediment removal. How to maximize the kinetic energy of hydraulic sediment transport and improve sediment removal efficiency through artificial and mechanical measures, coupled with reservoir regulation, is a major technical challenge that urgently needs to be addressed in reservoir sedimentation control. This invention addresses these issues by considering the sediment transport patterns in reservoirs of sediment-rich rivers from the perspective of improving reservoir sediment removal efficiency, based on the laws governing sediment movement in reservoirs. It studies the coordinated operation of mechanical dredging and hydraulic sediment transport, proposes a technology for enhancing the kinetic energy of reservoir sediment removal based on mechanical dredging and hydraulic regulation, and puts forward a sediment control method for water conservancy projects in sediment-rich rivers, providing technical support for sedimentation control in reservoirs of sediment-rich rivers.

[0005] Therefore, this invention proposes a method for sediment control in water conservancy projects on sandy rivers. Summary of the Invention

[0006] This invention provides a method for sediment control in water conservancy projects on sandy rivers. Based on the idea of ​​fully utilizing the kinetic energy of hydraulic scouring, it proposes a technology that combines hydraulic scouring with mechanical dredging to facilitate the efficient treatment of sediment in engineering projects.

[0007] This invention provides a method for sediment control in water conservancy projects on sandy rivers, comprising:

[0008] Step 1: Collect runoff and sediment data from the reservoir's hydrological stations, and analyze the characteristics of incoming water and sediment and the properties of floodwater and sediment.

[0009] Step 2: Collect reservoir operation data and reservoir sedimentation data, analyze the sedimentation process and sedimentation distribution in the reservoir area, and then obtain the reservoir sediment discharge pattern under different water and sediment conditions and operation methods.

[0010] Step 3: Collect reservoir design data to determine the scale of reservoir dredging and sediment control targets;

[0011] Step 4: Based on the reservoir sediment discharge pattern, the scale of reservoir dredging, and the sediment control target, and in conjunction with the water-sediment characteristics and flood sediment properties, formulate the reservoir sediment discharge operation method;

[0012] Step 5: Based on the measured water and sediment data and in accordance with the reservoir sediment discharge method, determine the changes in scouring and sedimentation in the reservoir area and the scouring efficiency. Then analyze the longitudinal and transverse cross-sectional morphology of the reservoir, the riverbed morphology, the riverbed size and the scouring range to determine the hydraulic dredging effect and the mechanical dredging effect.

[0013] Step 6: Determine the location of the silt-pushing into the channel and the annual silt-pushing volume, and formulate a reservoir sediment control scheme based on hydraulic regulation and mechanical silt-pushing into the channel, taking into account both the effects of hydraulic dredging and mechanical dredging.

[0014] Step 7: Control and dredge the reservoir based on the reservoir sediment control scheme.

[0015] Preferably, the annual siltation volume is determined, including:

[0016] Based on the siltation pattern, channel size and net scour volume of the reservoir area shaped by hydraulic dredging during the first flood season, the annual initial mechanical siltation volume and the annual initial hydraulic siltation volume are revised.

[0017] Based on the effect of mechanical dredging, the first parameter of the mechanical measures used during the non-flood season to push the silt and sand in the first area into the deep trench near the dam section was obtained;

[0018] Based on the first parameter, the modified annual initial mechanical silt pushing volume is further modified to obtain the first mechanical silt pushing volume;

[0019] Based on the effect of hydraulic dredging, the second parameter of the silt and sediment removal in the second area using hydraulic measures during the flood season is obtained;

[0020] Based on the second parameter, the modified annual initial hydraulic thrust volume is further modified to obtain the first hydraulic thrust volume.

[0021] Based on the first mechanical siltation volume and the first hydraulic siltation volume, the annual siltation volume is obtained.

[0022] Preferably, in the process of determining the scouring and sedimentation changes and scouring efficiency of the reservoir area by combining measured water and sediment data and according to the reservoir sediment discharge operation method, the process includes:

[0023] Based on the aforementioned reservoir sediment discharge method, and combined with the flood process and scouring results during the following year's flood season, the sediment carrying capacity of the aforementioned reservoir sediment discharge method is determined.

[0024] Preferably, the sediment control target is related to the characteristic reservoir capacity and reservoir dredging, and the specific formula is as follows:

[0025] Y = y(s1, s2)

[0026] Where s1 represents the characteristic reservoir capacity; s2 represents the dredging of the reservoir area.

[0027] Preferably, in formulating the reservoir sediment discharge operation method based on the reservoir sediment discharge pattern, the scale of reservoir dredging, and sediment control targets, and in conjunction with the aforementioned water-sediment characteristics and flood sediment properties, the method also includes:

[0028] Determine the current reservoir capacity; when the current reservoir capacity is greater than or equal to the preset reservoir capacity, select a matching first flow level from the first flow database.

[0029] When the current storage capacity is less than the preset storage capacity, a matching second flow level is selected from the second flow database;

[0030] Based on the matched flow rate, the flushing duration of the reservoir is determined, and the reservoir is flushed in accordance with the flushing method that matches the flushing duration.

[0031] Among them, when carrying out open flushing with lower water level, the water level in front of the dam is controlled to be lowered.

[0032] Preferably, the longitudinal and transverse morphology of the reservoir, the riverbed morphology, the riverbed size, and the scour range are analyzed to determine the effectiveness of hydraulic dredging and mechanical dredging, including:

[0033] Based on the longitudinal and transverse cross-sectional morphology of the reservoir, the morphology of the river channel, the scale of the river channel, and the scour range, the sediment carrying capacity of the water flow during the flood season, the siltation surface in front of the dam and the sediment discharge tunnel of the hub, the upstream scour and the scour along the route near the dam section are determined. The sediment discharge scheduling method is adopted to determine the longitudinal slope changes of the deep channel in the reservoir area, the changes of the two side slopes of the channel bottom, and the decrease of the scour volume in the reservoir area.

[0034] Based on the longitudinal slope changes of the deep channel, the side slope changes of the channel bottom, and the decrease in the scour volume of the reservoir area, it is determined whether the sediment-carrying capacity of the surplus water flow is less than the preset capacity.

[0035] If so, identify the mechanically operable parts of the reservoir and, during the non-flood season, use mechanical measures to push the silt and sand accumulated in the mechanically operable parts into the deep channel near the dam formed by scouring, and obtain the mechanical dredging effect based on the operation results;

[0036] Meanwhile, during the flood season, the effectiveness of hydraulic dredging is determined by draining the flood-prone sand and sediment pushed into the channel from the reservoir based on the flood capacity.

[0037] Preferably, the location for siltation into the channel and the annual siltation volume are determined, and a reservoir sediment control scheme based on hydraulic regulation and mechanical siltation is formulated, taking into account both hydraulic and mechanical siltation effects. This scheme includes:

[0038] Collect the current topographic information of the reservoir and the initial topographic information of the reservoir;

[0039] The current terrain information is compared with the initial terrain information to construct a terrain change model;

[0040] Based on the location of the siltation into the trench and the annual siltation volume, the point attributes of each model point on the topography-terrain change model are analyzed, and the surface information of the corresponding model is obtained. The model points on the surface information are classified by location, and the first dividing line of each model surface is obtained. A first label related to the region type of the area intersecting with the dividing line is set for each first dividing line.

[0041] Based on all the first dividing lines and all the first labels, the terrain change model is first cut to obtain independent cut blocks and non-independent cut blocks.

[0042] Determine the line direction, line length, and label weight of the first dividing line involved in each non-independent cutting block, determine the allowable cutting depth of the first dividing line involved in the corresponding non-independent cutting block, and then obtain the new independent cutting block;

[0043] Based on the flow velocity sensors installed on all independent cutting blocks, a set of mud and sand flow velocities for each independent cutting block is constructed.

[0044] At the same time, a pre-analysis is performed on each independent cut block to determine the current sedimentation type of the corresponding independent cut block, as well as the sedimentation volume and sedimentation morphology of each sedimentation type;

[0045] Obtain a first dredging index for the hydraulic dredging effect and a second dredging index for the mechanical dredging effect;

[0046] Determine the first correlation value between the first dredging index and the flow velocity set of each independent cutting block, the current siltation type, and the siltation volume and siltation morphology of each siltation type;

[0047] Determine the second correlation value between the second dredging index and the flow velocity set of each independent cut block, the current siltation type, and the siltation volume and siltation morphology for each siltation type;

[0048] Based on the first correlation value and the second correlation value, the required sediment control method for the corresponding independent cutting block is determined, thereby obtaining the sediment control scheme for the reservoir.

[0049] Preferably, determining a first correlation value between the first dredging index and the flow velocity set of each independent cut block, the current siltation type, and the siltation volume and morphology of each siltation type includes:

[0050]

[0051] p1 = h1(j1,j2,j3,j4)

[0052] Where, n1 represents the total number of the first dredging indicators; p1 represents the representative function symbol of the corresponding independent cutting block; h1(j1,j2,j3,j4) represents the representative function of the corresponding independent cutting block based on the velocity set j1, the current siltation type j2, the siltation volume j3 of each siltation type, and the siltation morphology j4; g1 i1 This represents the index representative function corresponding to the i1th first dredging index; sim i1 (g1 i1 ,p1) represents the similarity function between the representative function of the first dredging index corresponding to the i1th first dredging index and the representative function of the corresponding independent cutting block; max represents the maximum value sign; G1 represents the first correlation value.

[0053] Preferably, determining a second correlation value between the second dredging index and the flow velocity set of each independent cut block, the current siltation type, and the siltation volume and morphology for each siltation type includes:

[0054]

[0055] Where n2 represents the total number of the second dredging indicators; g2 i2 This represents the index representative function corresponding to the i2th second dredging index; sim i2 (g2 i2 ,p1) represents the similarity function between the representative function of the second dredging index corresponding to the i2th second dredging index and the representative function of the corresponding independent cutting block; G2 represents the first association value.

[0056] Preferably, based on the first correlation value and the second correlation value, the required sediment control method for the corresponding independent cutting block is determined, thereby obtaining the reservoir sediment control scheme, including:

[0057] A first correlation value for each independent cutting block is compared with the hydraulic control range, and a second correlation value is compared with the mechanical control range.

[0058] When the first comparison result is at the recommended hydraulic control level and the second comparison result is at the unrecommended mechanical control level, a hydraulic control label is set for the corresponding independent cutting block;

[0059] When the first comparison result is at the unrecommended hydraulic control level and the second comparison result is at the recommended mechanical control level, a mechanical control label is set for the corresponding independent cutting block;

[0060] When the first comparison result is at the recommended hydraulic control level and the second comparison result is at the recommended mechanical control level, set a hydraulic and mechanical combined control label for the corresponding independent cutting block;

[0061] When the first comparison result is not at the recommended hydraulic control level and the second comparison result is not at the recommended mechanical control level, set a pending label for the corresponding independent cutting block;

[0062] Based on all the labels set for the corresponding model, retrieve the corresponding reservoir sediment control scheme from the label-scheme database.

[0063] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0064] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0065] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0066] Figure 1 This is a flowchart illustrating a sediment control method for a water conservancy project on a sandy river, as described in an embodiment of the present invention.

[0067] Figure 2 This is a plan view of the dredging layout of Bajiazui Reservoir in an embodiment of the present invention;

[0068] Figure 3 This is the first typical cross-section of the dredging of Bajiazui Reservoir in an embodiment of the present invention;

[0069] Figure 4 This is the second typical cross-section of the dredging of Bajiazui Reservoir in an embodiment of the present invention;

[0070] Figure 5 This is a cutting diagram of an independent block in an embodiment of the present invention. Detailed Implementation

[0071] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0072] This invention provides a method for sediment control in water conservancy projects on sandy rivers, such as... Figure 1 As shown, it includes:

[0073] Step 1: Collect runoff and sediment data from the reservoir's hydrological stations, and analyze the characteristics of incoming water and sediment and the properties of floodwater and sediment.

[0074] In step 1, the runoff and sediment data include daily flow, sediment transport rate, sediment concentration, and flood hydrological elements over the years. Based on this, the analysis includes the annual distribution of water and sediment, interannual variation, sediment concentration variation, and water-sediment combination relationship. It also analyzes the sediment concentration and water-sediment ratio at different flow levels, and analyzes the changes in peak flood flow and flood sediment characteristics over the years.

[0075] In step 1, based on statistics from 1951 to 1996, the average annual inflow to Bajiazui Reservoir was 131 million m³. 3 Of which, during the main flood season of July and August, 0.61 billion cubic meters... 3 It accounts for 46.7% of the annual water volume; the average annual sediment inflow is 28.48 million tons, of which 22.72 million tons are transported during the main flood season (July-August), accounting for 79.8% of the annual sediment volume; the average annual sediment concentration is 218 kg / m³. 3 The average sediment content during the main flood season was 373 kg / m³. 3 The reservoir's flood peaks are characterized by high peak volume, small volume, short duration, and large sediment load. Peak duration generally does not exceed 20 hours, sometimes as short as 2-3 hours. The annual sediment load is mainly concentrated in a few rainstorm floods. Since 2000, due to changes in rainfall and the impact of water conservancy and soil conservation projects, the overall inflow into the reservoir has been relatively low (sedimentation was not monitored). The average inflow from 1997 to 2018 was 0.60 billion m³. 3 The inflow was about 54% less than that from 1951 to 1996, with the main flood season runoff in July and August being only 0.25 billion cubic meters. 3 Based on runoff-sediment transport relationship calculations, the multi-year average sediment transport from 1997 to 2018 was 6.22 million tons, with an average annual sediment concentration of 104 kg / m³. 3 The sediment content of the water flow remains high. The main source of moisture in the Puhe River basin is the transport of warm and humid air currents from the southeast. The weather system is characterized by the passage of a cold front, with heavy rainfall mainly occurring in July and August, characterized by high intensity and concentration. Floods in the basin are primarily formed by these heavy rainfalls, with major floods also mainly occurring in July and August. Due to the short duration and high intensity of these heavy rainfalls, coupled with the steep terrain and rapid confluence of waterways within the basin, flood events are generally characterized by a single-peak pattern of rapid rise and fall.

[0076] Step 2: Collect reservoir operation data and reservoir sedimentation data, analyze the sedimentation process and sedimentation distribution in the reservoir area, and then obtain the reservoir sediment discharge pattern under different water and sediment conditions and operation methods.

[0077] The data used, including reservoir sedimentation data, mainly include reservoir sedimentation volume, reservoir sediment discharge by lowering water level and open discharge, and sediment discharge by density current, to analyze the sedimentation process, sedimentation distribution, and sediment discharge patterns under different inflow and sedimentation conditions and operating methods.

[0078] Step 2, based on the measured data of reservoir sediment discharge scheduling, analyzes the sedimentation process, sediment distribution, and sediment discharge effect under different inflow and sediment conditions and operating methods in the reservoir area. This provides the foundation for formulating hydraulic dredging scheduling methods. After the completion of the spillway tunnel in 1998, the Bajiazui Reservoir had a certain discharge capacity, with a height difference of over 20m between the sedimentation surface and the dead water level in front of the dam, providing good conditions for open discharge scouring. Looking at the sediment discharge effect of the Bajiazui Reservoir during July and August of 2007 and 2008, the peak flow at Yaoxinzhuang Station reached 323 m³ / h on July 13, July 17, August 6, and August 29, 2007. 3 / s、323m 3 / s、118m 3 / s、166m 3 Four minor floods occurred per second; on July 21 and August 27, 2008, the Yaoxinzhuang station recorded peak flows of 268 m³ / s respectively. 3 / s、385m 3 Two floods occurred per second, causing erosion in the reservoir area. The sedimentation elevation of the riverbed in front of the dam dropped by nearly 20 meters compared to the 2004 erosion. The erosion extended along the river to about 5 km from the dam, with the river channel width ranging from 200 to 50 meters. The reservoir capacity below the 1110m elevation increased by 3.44 million cubic meters compared to 2004. 3 The reservoir's capacity has been partially restored. Therefore, the Bajiazui Reservoir possesses the conditions and technical support to restore its silt-damaged capacity through hydraulic dredging.

[0079] Step 3: Collect reservoir design data to determine the scale of reservoir dredging and sediment control targets;

[0080] In step 3, the Bajiazui Reservoir is located in Xifeng District, Qingyang City, Gansu Province, in the Loess Plateau region of the middle and lower reaches of the Puhe River, a tributary of the Jinghe River. The main stream of the Puhe River upstream of the reservoir dam site is about 105 km long, and the controlled drainage area is 3478 km². 2 The reservoir was completed in July 1962, with a capacity of 257 million cubic meters. 3 It was originally a homogeneous loess dam, which was subsequently heightened and reinforced multiple times, bringing its total reservoir capacity to 540 million cubic meters. 3 It is a large (2) type reservoir, a comprehensive reservoir mainly for flood control and urban water supply, while also serving irrigation and power generation. The normal water level of the reservoir is set at 1115m, and the designed total siltation volume after a 34-year + 100-year flood is 77.1 million cubic meters. 3 The effective reservoir capacity below the corresponding check flood level is 136.74 million m³. 3 The reservoir capacity is 20.3 million cubic meters below the normal water level of 1115m. 3 The reservoir capacity below the flood control limit level of 1111m is 6.35 million cubic meters. 3 According to the reservoir area survey results in October 2019, the remaining total storage capacity of the reservoir is 137.28 million cubic meters. 3The remaining reservoir capacity below the normal water level of 1115m is 5.39 million cubic meters. 3 The remaining reservoir capacity below the flood control limit water level of 1111m is 640,000 m³. 3 The corresponding reservoir has accumulated silt of 76.6 million cubic meters. 3 After 16 years of operation, the reservoir has reached its designed siltation level, and its total capacity is almost identical to the designed capacity. Due to rapid siltation, the current regulating capacity is only 26.5% of the designed regulating capacity, and the remaining flood control capacity is only 136.6 million cubic meters. 3 With a designed flood control capacity of 130.4 million cubic meters, 3 The difference is only 6.2 million m 3 To address the conflict between water use and sediment discharge, Qingyang City constructed the Wutaishan Regulating Reservoir in 2019, with a regulating capacity of 5.58 million cubic meters. 3 During the non-flood season, water is drawn from the Bajiazui Reservoir by gravity flow, which can be used to supply urban water during the main flood season when the reservoir is empty and discharging sediment. The Bajiazui Reservoir has the external conditions for empty reservoir discharge and sediment discharge.

[0081] Step 4: Based on the reservoir sediment discharge pattern, the scale of reservoir dredging, and the sediment control target, and in conjunction with the water-sediment characteristics and flood sediment properties, formulate the reservoir sediment discharge operation method;

[0082] The purpose of determining the method of reservoir sediment discharge is to demonstrate the conditions, timing, and water level control of sediment discharge.

[0083] In step 4, based on the analysis of the sediment transport flow pattern of the reservoir, when the reservoir is in the state of impounding sediment transport, siltation will inevitably occur in the reservoir area. Scouring is only possible when the reservoir is dominated by uniform open-flow sediment transport. To form a uniform open-flow sediment transport pattern, the water level must be lowered to the point of near-empty storage. Therefore, the necessary condition for the reservoir to restore its capacity is to lower the water level to the point of near-empty storage, so that the water flow in the entire reservoir area is dominated by a uniform open-flow sediment transport pattern. At the same time, it is required that the siltation in the reservoir in the early stage reaches a certain level, with silt available for scouring, forming topographical conditions conducive to scouring. The inflow is a large-volume flood process, the reservoir has a large discharge scale, and the duration and number of times the reservoir scouring and discharging sediment must be guaranteed.

[0084] The effect of reservoirs lowering water levels and releasing water for scouring is related to a variety of factors, including the conditions of incoming water and sediment, the previous scouring and sedimentation conditions in the reservoir area, the magnitude of the water level drop in front of the dam, and the duration of the scouring process.

[0085] ① The initial sedimentation and scouring conditions in the reservoir area significantly affect the water level reduction and scouring effect. Under the same conditions, the scouring efficiency is significantly higher when the reservoir area is in a sedimentation state than when it is in a scouring state.

[0086] ② Regarding the selection of the flushing flow rate, different reservoirs have different requirements. Reservoirs with large capacity and long backwater distances should choose relatively large flow rates; while reservoirs with small capacity and short backwater distances can achieve good flushing effects with smaller flow rates. This ensures a certain flushing volume and intensity, high flushing efficiency, and a certain probability of occurrence. While large-flow floods have a better flushing effect, their occurrence is relatively less frequent.

[0087] ③ The duration of scouring significantly affects scouring intensity and efficiency. Shorter scouring durations generally result in greater scouring intensity and efficiency, but the total scouring volume is relatively smaller, and the scouring area is also relatively smaller. Due to the relatively short scouring duration at the Qingtongxia Reservoir, mostly less than 3 days, its scouring range is limited to a few kilometers near the dam, primarily characterized by headward scouring, failing to fully utilize the scouring effect along the dam's course.

[0088] ④ When lowering the water level for open flushing, the water level in front of the dam should be lowered as much as possible. The greater the difference in elevation between the water level and the sedimentation surface in front of the dam, the greater the upstream flushing effect of the water and the better the sediment removal effect.

[0089] In step 4, the Bajiazui Reservoir area is severely silted up, with silt available for scouring, creating favorable topographical conditions. Based on the annual distribution characteristics of floodwater and sediment entering the Bajiazui Reservoir, sediment mainly originates from June to September, accounting for approximately 95% of the annual sediment load, with July and August accounting for 80% of the total. Furthermore, considering the timing of floods, the largest flood peaks historically occur from late June to mid-September, primarily in July and August. Only by aligning the timing of sediment discharge with the floodwater and sediment load occurrence can effective sediment removal from the reservoir area be achieved. In conjunction with the approved operation mode of the reservoir, the open-release sediment discharge period is determined to be from July 1st to August 31st. During the reservoir's water storage operation from June 20th to June 30th and September 1st to September 15th, the operating water level will be controlled to not exceed the flood control limit of 1111m, with open-release sediment discharge as needed.

[0090] Through the joint operation of the Bajiazui and Wutaishan reservoirs, in normal years, the water supply to the urban area can be met during the sediment discharge period of the Bajiazui reservoir from July to August. In exceptionally dry years, if the water supply to the urban area cannot be met during the planned sediment discharge period, the sediment discharge time needs to be adjusted appropriately based on the reservoir's water storage status before the flood season.

[0091] In this embodiment, the sediment discharge methods of reservoirs in sandy rivers are relatively complex, including reservoir water level lowering for sediment discharge, open discharge, and density current discharge. Different sediment discharge scheduling methods have different applicable conditions, water and sediment movement patterns, and sediment discharge effects. Therefore, it is necessary to demonstrate the appropriate sediment discharge method based on the actual conditions of the reservoir. Analyzing the inflow water and sediment conditions, reservoir scheduling indicators, water and sediment movement patterns, changes in reservoir scouring and deposition patterns, and sediment discharge effects in actual reservoir sediment discharge scheduling methods can provide a foundation for formulating reservoir hydraulic dredging scheduling methods.

[0092] Step 5: Based on the measured water and sediment data and in accordance with the reservoir sediment discharge method, determine the changes in scouring and sedimentation in the reservoir area and the scouring efficiency. Then analyze the longitudinal and transverse cross-sectional morphology of the reservoir, the riverbed morphology, the riverbed size and the scouring range to determine the hydraulic dredging effect and the mechanical dredging effect.

[0093] In step 5, based on the understanding of the characteristics of the Puhe River's water and sediment and the changes in water and sediment in recent years, and in accordance with the requirements for water and sediment conditions in the scheme calculations of the sediment discharge application mode demonstration, three design water and sediment representative series are proposed. The principles for selecting the selected water and sediment representative series are as follows: First, the selected water and sediment representative series should be composed of as few natural continuous series as possible; second, the selected water and sediment series years should reflect the water and sediment conditions in years with abundant, normal, and dry water, and appropriately consider some years with large water and high sediment and some years with low water and low sediment; third, the selected water and sediment series should represent the recent water and sediment conditions, and the average value should be close to the average value of the long series from 1997 to 2018; fourth, since the Puhe River's rainstorms and floods are concentrated in July and August, with short peak durations, heavy rain lasting 6 to 10 hours and rainstorms lasting about 2 to 3 hours, the water and sediment design for July and August will use a 24-hour water and sediment period.

[0094] In this step, in determining the effectiveness of mechanical dredging, the reservoir siltation control requirements are considered, and the reservoir scouring and siltation patterns are calculated based on mathematical models to demonstrate the locations, volumes, and methods of mechanical dredging.

[0095] Among them, Bajiazui Reservoir has low water levels and high sediment content, resulting in a large volume of dredging and an urgent need for dredging. However, the recent inflow of floodwaters has decreased in both volume and frequency. Model calculations show that hydraulic dredging alone is insufficient to achieve the dredging target in the short term, necessitating the supplementary mechanical dredging measures. Considering the reservoir capacity and sediment distribution, reservoir topography, scouring and sedimentation characteristics, and the current hydraulic dredging capabilities, the mechanical dredging area should ideally be deployed from the oil terminal to the inlet of the desilting tunnel, a length of approximately 6 km.

[0096] The hydraulic dredging effect calculated from the model shows that the greater the difference in elevation between the water level in front of the dam and the siltation surface, the farther the upstream scouring development distance, and the greater the hydraulic scouring volume. Taking full advantage of the strong scouring capacity of the section in front of the dam, silt from the banks on both sides is artificially transported into a deep channel based on the channel formed by the previous scouring, increasing the elevation of the siltation surface in front of the dam. This silt is then flushed out of the reservoir during the flood season, improving the hydraulic dredging capacity. Based on the fact that upstream scouring is mainly concentrated within 3km of the dam, and fully utilizing the sediment-carrying capacity of the flood during the open discharge period, silt from the banks within approximately 3km of the dam in the lower section of the reservoir is transported into the scourged deep channel and flushed out of the reservoir during the open discharge period. For the silt within approximately 3km of the upper section near the oil terminal, considering the advantages of dredgers such as good maneuverability, no time or geographical restrictions, low water consumption, and low labor costs, dredgers are used as much as possible in the construction method.

[0097] Step 6: Determine the location of the silt-pushing into the channel and the annual silt-pushing volume, and formulate a reservoir sediment control scheme based on hydraulic regulation and mechanical silt-pushing into the channel, taking into account both the effects of hydraulic dredging and mechanical dredging.

[0098] Step 7: Control and dredge the reservoir based on the reservoir sediment control scheme.

[0099] The beneficial effects of the above technical solutions are as follows: based on the idea of ​​fully utilizing the kinetic energy of hydraulic scouring, we have explored a synergistic approach to enhance the efficiency of hydraulic dredging by supplementing it with mechanical dredging. We have also studied reservoir sediment control technology based on hydraulic regulation and mechanical dredging into the channel, and proposed a method for sediment control in water conservancy projects for rivers with high sediment content. This provides technical support for achieving the goals of reservoir capacity restoration and sediment control in rivers with high sediment content.

[0100] This invention provides a method for sediment control in water conservancy projects on sandy rivers, determining the annual siltation volume, including:

[0101] Based on the siltation pattern, channel size and net scour volume of the reservoir area shaped by hydraulic dredging during the first flood season, the annual initial mechanical siltation volume and the annual initial hydraulic siltation volume are revised.

[0102] Based on the effect of mechanical dredging, the first parameter of the mechanical measures used during the non-flood season to push the silt and sand in the first area into the deep trench near the dam section was obtained;

[0103] Based on the first parameter, the modified annual initial mechanical silt pushing volume is further modified to obtain the first mechanical silt pushing volume;

[0104] Based on the effect of hydraulic dredging, the second parameter of the silt and sediment removal in the second area using hydraulic measures during the flood season is obtained;

[0105] Based on the second parameter, the modified annual initial hydraulic thrust volume is further modified to obtain the first hydraulic thrust volume.

[0106] Based on the first mechanical siltation volume and the first hydraulic siltation volume, the annual siltation volume is obtained.

[0107] In this embodiment, based on the siltation morphology and scale of the reservoir channel shaped by hydraulic dredging during the first flood season, as well as the net scouring volume of the reservoir, the annual mechanical silt-pushing volume is adjusted. During the non-flood season, mechanical measures are used to push silt deposited on the beach or upstream that cannot be directly flushed out of the reservoir by hydraulic means into the deep channel near the dam. According to the established reservoir sediment discharge operation mode, the sediment is flushed out of the reservoir by hydraulic means. The amount of silt pushed into the channel is determined based on the scale of the river channel formed by hydraulic scouring in the early stage and the hydraulic scouring effect. At the same time, an open channel with a certain width and depth in the center of the deep channel is retained to ensure that small floods do not overflow the beach and to maintain the hydraulic scouring power during the reservoir sediment discharge operation.

[0108] In this embodiment, the first parameter is corrected for the amount of silt pushed after mechanical measures are adopted, and the second parameter is similar in principle to the first parameter.

[0109] For example: The revised amount of siltation = revised amount of siltation * adjustment coefficient corresponding to the first parameter.

[0110] The beneficial effect of the above technical solution is that by correcting the amount of siltation according to hydraulic and mechanical parameters, the rationality of the annual siltation calculation can be effectively guaranteed.

[0111] This invention provides a method for sediment control in water conservancy projects on sandy rivers. Combining measured water and sediment data with the described reservoir sediment discharge operation method, the method determines the scouring and deposition changes and scouring efficiency in the reservoir area, including:

[0112] Based on the aforementioned reservoir sediment discharge method, and combined with the flood process and scouring results during the following year's flood season, the sediment carrying capacity of the aforementioned reservoir sediment discharge method is determined.

[0113] In this embodiment, according to the established sediment discharge method, the reservoir area is flushed by the flood process during the following flood season to discharge the sediment brought in during the flood season and the silt pushed into the deep channel, so as to give full play to the sediment carrying capacity of the water flow during the reservoir's hydraulic sediment discharge.

[0114] The beneficial effect of the above technical solution is that by determining the sand-carrying capacity, a foundation is provided for subsequent solution determination.

[0115] This invention provides a method for sediment control in water conservancy projects on sandy rivers. The sediment control target is related to the characteristic reservoir capacity and reservoir dredging, and the specific formula is as follows:

[0116] Y = y(s1, s2)

[0117] Where s1 represents the characteristic reservoir capacity; s2 represents the dredging of the reservoir area.

[0118] In this embodiment, the scale of reservoir dredging and the sediment control target refer to the various characteristic reservoir capacities required to maintain the normal operation of the reservoir's development tasks and functions such as flood control, power generation, water supply, irrigation, and navigation, and to realize the comprehensive utilization benefits of the reservoir, based on the current siltation status of the reservoir area. This requires the restoration of characteristic reservoir capacities such as design regulation capacity and flood control capacity through reservoir dredging, as well as the required dredging volume and dredging locations in the reservoir area, in order to achieve the reservoir sediment control target.

[0119] In this embodiment, Y is a function symbol for the sediment control target, and y(s1,s2) represents the sediment control target.

[0120] The beneficial effect of the above technical solution is that by setting functions, it is easier to construct sediment control targets.

[0121] This invention provides a method for sediment control in water conservancy projects on sandy rivers. Based on the reservoir sediment discharge pattern, the scale of reservoir dredging, and sediment control targets, and in conjunction with the characteristics of incoming water and sediment from floods, the method for determining the reservoir sediment discharge operation also includes:

[0122] Determine the current reservoir capacity; when the current reservoir capacity is greater than or equal to the preset reservoir capacity, select a matching first flow level from the first flow database.

[0123] When the current storage capacity is less than the preset storage capacity, a matching second flow level is selected from the second flow database;

[0124] Based on the matched flow rate, the flushing duration of the reservoir is determined, and the reservoir is flushed in accordance with the flushing method that matches the flushing duration.

[0125] Among them, when carrying out open flushing with lower water level, the water level in front of the dam is controlled to be lowered.

[0126] In this embodiment, hydraulic dredging refers to a sediment flushing technique that uses water flow to flush away accumulated sediment from the reservoir and restore its capacity through reservoir scheduling. The control indicators for sediment flushing scheduling generally include sediment flushing conditions, timing, control water level, and duration.

[0127] The key to hydraulic dredging and restoring reservoir capacity is to lower the reservoir level to release water and create a uniform open flow pattern for sediment transport in the reservoir area. At the same time, it is required that the reservoir has accumulated a certain level of sediment in the early stage, so that there is sediment to be washed away, and the terrain conditions are conducive to scouring.

[0128] The inflow is a large-volume flood process, the reservoir has a large discharge capacity, and the duration and frequency of reservoir flushing and sediment removal must be guaranteed.

[0129] The timing of sediment discharge should coincide with the occurrence of floods and sediment to effectively discharge sediment from the reservoir area and reduce siltation.

[0130] The scouring and sedimentation conditions in the reservoir area in the early stage have a significant impact on the effect of lowering the water level and scouring. Under the same conditions, the scouring efficiency is significantly higher when the reservoir area is in a sedimentation state in the early stage than when it is in a scouring state in the early stage.

[0131] Regarding the selection of flushing flow rate, different reservoirs have different situations. Reservoirs with large capacity and long backwater distance should choose a relatively large flow rate, while reservoirs with small capacity and short backwater distance can achieve a good flushing effect by using a smaller flow rate flood. This ensures a certain flushing volume and intensity, high flushing efficiency, and a certain probability of occurrence. While the flushing effect of a large flow flood is certainly better, the chance of it occurring is relatively less.

[0132] The duration of scouring has a significant impact on scouring intensity and efficiency. Shorter scouring duration generally results in greater scouring intensity and higher scouring efficiency, but the total amount of scouring is relatively smaller, and the scope of scouring development is relatively smaller. It is mainly headwater scouring and fails to give full play to the role of scouring along the route.

[0133] When lowering the water level for open scouring, the water level in front of the dam should be lowered as much as possible. The greater the difference in elevation between the water level and the sedimentation surface in front of the dam, the greater the upstream scouring effect of the water flow and the better the sediment removal effect.

[0134] The beneficial effects of the above technical solution are: by comparing the reservoir capacity, it is easier to reasonably determine the flow level, and thus easier to determine the flushing method to achieve the flushing of the reservoir.

[0135] This invention provides a method for sediment control in water conservancy projects on sandy rivers. It analyzes the longitudinal and cross-sectional morphology of the reservoir, the riverbed morphology, the riverbed size, and the scour range to determine the effectiveness of hydraulic dredging and mechanical dredging. The method includes:

[0136] Based on the longitudinal and transverse cross-sectional morphology of the reservoir, the morphology of the river channel, the scale of the river channel, and the scour range, the sediment carrying capacity of the water flow during the flood season, the siltation surface in front of the dam and the sediment discharge tunnel of the hub, the upstream scour and the scour along the route near the dam section are determined. The sediment discharge scheduling method is adopted to determine the longitudinal slope changes of the deep channel in the reservoir area, the changes of the two side slopes of the channel bottom, and the decrease of the scour volume in the reservoir area.

[0137] Based on the longitudinal slope changes of the deep channel, the side slope changes of the channel bottom, and the decrease in the scour volume of the reservoir area, it is determined whether the sediment-carrying capacity of the surplus water flow is less than the preset capacity.

[0138] If so, identify the mechanically operable parts of the reservoir and, during the non-flood season, use mechanical measures to push the silt and sand accumulated in the mechanically operable parts into the deep channel near the dam formed by scouring, and obtain the mechanical dredging effect based on the operation results;

[0139] Meanwhile, during the flood season, the effectiveness of hydraulic dredging is determined by draining the flood-prone sand and sediment pushed into the channel from the reservoir based on the flood capacity.

[0140] In this embodiment, the initial scouring and sedimentation conditions of the reservoir area significantly affect the scouring effect of lowering the water level. Under the same conditions, the scouring efficiency is significantly higher when the reservoir is in a sedimentation state than when it is in a scouring state. During the reservoir's open-discharge operation during the sediment discharge period, as the reservoir operates with open discharge during the flood season, the deep channels in the reservoir area gradually develop, the longitudinal slope of the channel bottom gradually becomes gentler, and the slopes on both sides of the deep channels also tend to stabilize, resulting in a gradual decrease in the amount of scouring and sedimentation during open discharge.

[0141] like Figure 2 , Figure 3 as well as Figure 4As shown, during the dredging of the Bajiazui Reservoir, in order to fully utilize the sediment-carrying capacity of the floodwaters during the flood season, the silt from the beach was transported into the deep channel formed during the previous year's flood season. At the same time, an open channel with a certain flow capacity was retained in the center of the deep channel to ensure that small floods did not overflow the beach during the dredging. In the first year (July 1st of the first year to June 30th of the second year), the silt from the open flood season scoured 2.6 million cubic meters of land. 3 630,000 m³ of silt was returned during the non-flood season. 3 The net siltation volume in the first year was 1.97 million cubic meters. 3 During the first year's non-flood season, artificial assistance was used to push silt from the beach into the deep scour channels formed by flood discharge. The amount pushed was approximately 70% of the annual net scour and sedimentation volume, totaling 1.4 million cubic meters. 3 During the second year's flood season (July 1st of the second year to June 30th of the third year), this portion of the silt was flushed out of the reservoir area, simultaneously eroding the natural riverbed and forming deep channels. This cycle repeated for four years. In the fifth year, the reservoir operated with open discharge during the flood season, and the erosion volume by the end of the flood season was 2.6 million cubic meters. 3 This created a deep channel, allowing the reservoir to resume normal operation. The total amount of silt removal work involved pushing silt into the channel was 5.6 million cubic meters. 3 .

[0142] The dredging area extends approximately 6.0 km from the entrance of the sand discharge tunnel to the vicinity of the oil terminal platform in the reservoir area. After deducting the area of ​​the deep channel formed during the open discharge, the remaining beach area is approximately 2.418 million m². 2 The average dredging depth is approximately 2.3 meters. The deep channels of this reservoir were formed by upstream scouring, becoming deeper and wider closer to the discharge tunnel inlet. Therefore, the deep channels for accumulating silt from the riverbank are mainly concentrated in the downstream 2.5 km section. However, to avoid clogging the discharge tunnel, no silt is piled up within 300 meters upstream of the discharge tunnel. The dredging plan uses the discharge tunnel inlet as the starting point, the oil terminal platform as the ending point, and the existing river channel centerline as the centerline of the dredging plane. Silt from the riverbank section from K0+000 to K1+700 is transported to the deep channels using cutter suction dredgers, with an average transport distance of approximately 300 meters. Silt from the riverbank section from K1+700 to K2+500 is also transported to the deep channels using cutter suction dredgers, with an average transport distance of approximately 1000 meters. The silt above the beach between K2+500 and K6+000 is transported to the downstream deep channel by excavators and dump trucks, with an average transport distance of 3.0 km; the silt below the beach is transported to the deep channel by cutter suction dredgers, with an average transport distance of 3.0 km.

[0143] In this embodiment, the unloading measure refers to mechanical dredging, which is a dredging technique that uses dredgers, sludge pumps, excavators, and other mechanical means to remove silt from the reservoir area. Mechanical dredging is not limited by the layout of the reservoir or the conditions of incoming water and sediment, and its construction is flexible. After decades of development, the construction technology is relatively mature and it is widely used in small and medium-sized reservoirs. However, due to its high cost, it is suitable for reservoir projects with a small silt removal volume.

[0144] The beneficial effects of the above technical solution are: by determining the relevant parameters of the reservoir, it is easier to reasonably determine the effects of mechanical measures and hydraulic measures, thus providing an effective basis for the subsequent construction of control schemes.

[0145] This invention provides a method for sediment control in water conservancy projects on sandy rivers. It determines the location of siltation in the channel and the annual siltation volume, and, combining the effects of hydraulic and mechanical dredging, formulates a reservoir sediment control scheme based on hydraulic regulation and mechanical siltation in the channel, including:

[0146] Collect the current topographic information of the reservoir and the initial topographic information of the reservoir;

[0147] The current terrain information is compared with the initial terrain information to construct a terrain change model;

[0148] Based on the location of the siltation into the trench and the annual siltation volume, the point attributes of each model point on the topography-terrain change model are analyzed, and the surface information of the corresponding model is obtained. The model points on the surface information are classified by location, and the first dividing line of each model surface is obtained. A first label related to the region type of the area intersecting with the dividing line is set for each first dividing line.

[0149] Based on all the first dividing lines and all the first labels, the terrain change model is first cut to obtain independent cut blocks and non-independent cut blocks.

[0150] Determine the line direction, line length, and label weight of the first dividing line involved in each non-independent cutting block, determine the allowable cutting depth of the first dividing line involved in the corresponding non-independent cutting block, and then obtain the new independent cutting block;

[0151] Based on the flow velocity sensors installed on all independent cutting blocks, a set of mud and sand flow velocities for each independent cutting block is constructed.

[0152] At the same time, a pre-analysis is performed on each independent cut block to determine the current sedimentation type of the corresponding independent cut block, as well as the sedimentation volume and sedimentation morphology of each sedimentation type;

[0153] Obtain a first dredging index for the hydraulic dredging effect and a second dredging index for the mechanical dredging effect;

[0154] Determine the first correlation value between the first dredging index and the flow velocity set of each independent cutting block, the current siltation type, and the siltation volume and siltation morphology of each siltation type;

[0155] Determine the second correlation value between the second dredging index and the flow velocity set of each independent cut block, the current siltation type, and the siltation volume and siltation morphology for each siltation type;

[0156] Based on the first correlation value and the second correlation value, the required sediment control method for the corresponding independent cutting block is determined, thereby obtaining the sediment control scheme for the reservoir.

[0157] In this embodiment, the initial topographic information is specified as being obtained when there is no siltation in the reservoir, while the current topographic information refers to the siltation status of the reservoir from the start of its construction to the present moment.

[0158] In this embodiment, since the reservoir has been used in history, the location of the silt-push channel and the annual silt-push volume can be inferred. This allows us to determine the situation of each location point in the reservoir model, such as whether silt is easy to accumulate, whether the accumulated silt is difficult to clean, or what types of silt are likely to be stored at that location.

[0159] In this embodiment, after determining the point attributes of each model point on the corresponding model, the surface information based on the model can be obtained. After obtaining the terrain change model, an external three-dimensional contour of the model can be obtained. Therefore, the model surface can be obtained.

[0160] In this embodiment, when classifying the positions according to model points, the point range formed by model points of the same type can be obtained. Therefore, the range line of the point range, that is, the first dividing line, can be obtained. If there are other types of points in the point range that do not affect the overall point position division of the corresponding range, the other types of points can be ignored.

[0161] In this embodiment, the region type refers to the region type within and outside the range corresponding to the line, and a first label can be set.

[0162] In this embodiment, after the area is divided, under normal circumstances, only the region on the top view of the model is divided according to the first dividing line. Therefore, independent blocks will exist. However, it is unavoidable that the model will have inconsistent mud and sand types in the upper and lower parts. Therefore, it is necessary to cut the non-independent blocks according to the relevant line direction, line length, and label weight to ensure the existence of independent blocks. Specifically, as follows... Figure 5 As shown, a1 represents a non-independent cutting block, and a2 and a3 represent independent cutting blocks after cutting.

[0163] In this embodiment, sensors are installed in areas such as siltation in the reservoir, so that the silt flow velocity of each individual cut block can be collected.

[0164] In this embodiment, the pre-analysis is to intuitively obtain information such as the type, size, volume, and shape of the siltation in the cut block.

[0165] In this embodiment, the first dredging index is related to the magnitude, range, type, and area of ​​the hydraulic impact, while the second dredging index is related to the mechanical cleaning depth, range, and type.

[0166] The beneficial effects of the above technical solution are as follows: by acquiring and changing the model, and then by acquiring the point attributes of each point on the model, the model points are classified to determine different dividing lines and set labels for the lines, thereby obtaining independent blocks. Furthermore, by analyzing each independent block and associating it with different dredging indicators, a reservoir sediment control plan can be effectively formulated, providing a guarantee for subsequent reservoir sediment dredging.

[0167] This invention provides a method for sediment control in water conservancy projects on sandy rivers, which determines a first correlation value between a first dredging index and the velocity set of each independent cut block, the current sedimentation type, and the sedimentation volume and morphology of each sedimentation type, including:

[0168]

[0169] p1 = h1(j1,j2,j3,j4)

[0170] Where, n1 represents the total number of the first dredging indicators; p1 represents the representative function symbol of the corresponding independent cutting block; h1(j1,j2,j3,j4) represents the representative function of the corresponding independent cutting block based on the velocity set j1, the current siltation type j2, the siltation volume j3 of each siltation type, and the siltation morphology j4; g1 i1 This represents the index representative function corresponding to the i1th first dredging index; sim i1 (g1 i1 ,p1) represents the similarity function between the representative function of the first dredging index corresponding to the i1th first dredging index and the representative function of the corresponding independent cutting block; max represents the maximum value sign; G1 represents the first correlation value.

[0171] Preferably, determining a second correlation value between the second dredging index and the flow velocity set of each independent cut block, the current siltation type, and the siltation volume and morphology for each siltation type includes:

[0172]

[0173] Where n2 represents the total number of the second dredging indicators; g2 i2 This represents the index representative function corresponding to the i2th second dredging index; sim i2 (g2 i2,p1) represents the similarity function between the representative function of the second dredging index corresponding to the i2th second dredging index and the representative function of the corresponding independent cutting block; G2 represents the first association value.

[0174] In this embodiment, the process of comparing the similarity between functions mainly relies on the representative information of the function corresponding to different indicators and the representative information of the corresponding independent cutting block to calculate the similarity, and finally obtain the association value.

[0175] For example, the representative information corresponding to the first dredging index 1 is that silt with a morphology of 1 can be cleaned, and the corresponding silt morphology in the representative function is also 1. In this case, the similarity value is considered to be 0.5, and so on, and sim i1 (g1 i1 ,p1) and sim i2 (g2 i2 The range of values ​​for p1 is (0, 1).

[0176] The beneficial effects of the above technical solution are: by calculating the correlation values ​​of the first dredging index and various parameters involved in the cutting block according to different formulas, and calculating the key values ​​of the second dredging index and various parameters involved in the cutting block, a reasonable reference basis can be effectively provided for the subsequent determination of sediment control scheme.

[0177] This invention provides a sediment control method for a water conservancy project on a sandy river. Based on a first correlation value and a second correlation value, the required sediment control method for a corresponding independent segment is determined, thereby obtaining a reservoir sediment control scheme for the reservoir. The method includes:

[0178] A first correlation value for each independent cutting block is compared with the hydraulic control range, and a second correlation value is compared with the mechanical control range.

[0179] When the first comparison result is at the recommended hydraulic control level and the second comparison result is at the unrecommended mechanical control level, a hydraulic control label is set for the corresponding independent cutting block;

[0180] When the first comparison result is at the unrecommended hydraulic control level and the second comparison result is at the recommended mechanical control level, a mechanical control label is set for the corresponding independent cutting block;

[0181] When the first comparison result is at the recommended hydraulic control level and the second comparison result is at the recommended mechanical control level, set a hydraulic and mechanical combined control label for the corresponding independent cutting block;

[0182] When the first comparison result is not at the recommended hydraulic control level and the second comparison result is not at the recommended mechanical control level, set a pending label for the corresponding independent cutting block;

[0183] Based on all the labels set for the corresponding model, retrieve the corresponding reservoir sediment control scheme from the label-scheme database.

[0184] In this embodiment, both the water control range and the mechanical control range are preset and can be matched with the associated values ​​to determine whether to recommend a control level.

[0185] In this embodiment, the tag-scheme database includes combinations of tags from different independent blocks and schemes that match those combinations. Therefore, reservoir sediment control schemes that match the tags can be retrieved.

[0186] The beneficial effects of the above technical solution are: by comparing the correlation value with the corresponding control range, it is possible to effectively determine whether to carry out hydraulic control or mechanical control, and thus determine the overall reservoir sediment control scheme.

[0187] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for controlling sediment in a hydraulic complex of a multi-sand river, characterized in that, The method comprises the following steps: Step 1: collecting runoff and sediment data of an incoming hydrological station, analyzing incoming water and sediment characteristics and flood sediment characteristics; Step 2: collecting reservoir operation data and reservoir sedimentation data, analyzing the sedimentation process and distribution of the reservoir area, and then obtaining the reservoir sediment discharge rule under different incoming water and sediment conditions and operation modes; Step 3: collecting reservoir design data, determining the reservoir dredging scale and sediment control target; Step 4: according to the reservoir sediment discharge rule, the reservoir dredging scale and the sediment control target, and in combination with the water and sediment characteristics and the flood sediment characteristics, a reservoir sediment discharge operation mode is formulated; Step 5: in combination with the measured water and sediment data, and according to the reservoir sediment discharge operation mode, the scouring and silting changes and the scouring efficiency of the reservoir area are determined, and then the longitudinal and transverse section forms, the river channel form, the river channel scale and the scouring range of the reservoir are analyzed, and the hydraulic dredging effect and the mechanical dredging effect are determined; Step 6: the position of pushing silt into the groove and the annual pushing silt amount are determined, and in combination with the hydraulic dredging effect and the mechanical dredging effect, a reservoir sediment control scheme based on hydraulic regulation and mechanical pushing silt into the groove is formulated; Step 7: the reservoir is controlled and dredged based on the reservoir sediment control scheme; wherein the annual pushing silt amount is determined by: According to the reservoir channel silting form, the reservoir channel scale and the net scouring amount of the reservoir formed by the hydraulic dredging in the first flood season, the annual mechanical initial pushing silt amount and the annual hydraulic initial pushing silt amount are corrected; Based on the mechanical dredging effect, a first parameter of the mechanical measures adopted in the non-flood season to push the silting sediment in the first area into the deep groove near the dam section is obtained; Based on the first parameter, the annual mechanical initial pushing silt amount is further corrected to obtain a first mechanical pushing silt amount; Based on the hydraulic dredging effect, a second parameter of the hydraulic measures adopted in the flood season to clean the silt sediment in the second area is obtained; Based on the second parameter, the annual hydraulic initial pushing silt amount is further corrected to obtain a first hydraulic pushing silt amount; Based on the first mechanical pushing silt amount and the first hydraulic pushing silt amount, the annual pushing silt amount is obtained.

2. The method of claim 1, wherein the method is characterized by, In the process of determining the scouring and silting changes and the scouring efficiency of the reservoir area in combination with the measured water and sediment data and according to the reservoir sediment discharge operation mode, the process comprises: Based on the reservoir sediment discharge operation mode and in combination with the flood process and the scouring result of the reservoir area in the next flood season, the sediment carrying capacity of the reservoir sediment discharge operation mode is determined.

3. The method of claim 1, wherein the method is characterized by, In the process of formulating the reservoir sediment discharge operation mode according to the reservoir sediment discharge rule, the reservoir dredging scale and the sediment control target and in combination with the water and sediment characteristics and the flood sediment characteristics, the process further comprises: determining the current reservoir capacity of the reservoir, and when the current reservoir capacity is greater than or equal to a preset reservoir capacity, selecting a matched first flow level from a first flow database; when the current reservoir capacity is less than the preset reservoir capacity, selecting a matched second flow level from a second flow database; determining the scouring duration of the reservoir according to the matched flow level, and implementing the scouring of the reservoir according to a scouring mode matched with the scouring duration; wherein when the lowering water level open discharge scouring is performed, the dam front water level is controlled to be lowered.

4. The method of claim 1, wherein the method is characterized by, Analyzing the longitudinal and transverse section shape, river channel shape, river channel scale and scouring range of the reservoir to determine the hydraulic dredging effect and mechanical dredging effect, including: Based on the longitudinal and transverse section shape, river channel shape, river channel scale and scouring range of the reservoir, the water flow sediment carrying capacity in flood season, the dam front deposition surface and the hub sediment discharge tunnel, the upstream scouring and along-channel scouring effect of the near-dam section are determined, and the deep groove longitudinal slope change, the groove bottom two side slope change and the reservoir scouring amount decrease are determined by using the sediment discharge scheduling method. Based on the deep groove longitudinal slope change, the groove bottom two side slope change and the reservoir scouring amount decrease, it is determined whether the role of the surplus water flow sediment carrying capacity is less than the preset role. If so, the mechanical operable part of the reservoir is determined, and in the non-flood season, the mechanical measures are used to push the accumulated sediment in the mechanical operable part into the deep groove near the dam section formed by scouring, and the mechanical dredging effect is obtained according to the operation result. At the same time, in the flood season, the flood capacity is used to discharge the flood season sediment and the sediment pushed into the groove from the reservoir to determine the hydraulic dredging effect.

5. The method of claim 1, wherein the method is characterized by, The push-sediment-into-groove position and annual push-sediment-into-groove amount are determined, and the water reservoir sediment control scheme based on hydraulic regulation and mechanical push-sediment-into-groove is formulated by combining the hydraulic dredging effect and the mechanical dredging effect, including: Collecting the current topographic information of the reservoir and the initial topographic information of the reservoir; Comparing the current topographic information with the initial topographic information to build a topographic change model; Based on the push-sediment-into-groove position and annual push-sediment-into-groove amount, analyzing the point attributes of each model point on the topographic change model, and obtaining the face information of the corresponding model, the model points on the face information are position classified to obtain the first division line of each model face, and the first label related to the region type of the intersection region of each first division line is set; According to all first division lines and all first labels, the topographic change model is first cut to obtain independent cutting blocks and non-independent cutting blocks; Determine the line direction, line length and first label weight of the first division line involved in each non-independent cutting block, determine the allowed cutting depth of the first division line involved in the corresponding non-independent cutting block, and then obtain a new independent cutting block; Based on the flow velocity sensors set on all independent cutting blocks, a sediment flow velocity set corresponding to the independent cutting block is constructed; At the same time, each independent cutting block is pre-analyzed to determine the current deposition type of the corresponding independent cutting block and the deposition volume and deposition form of each deposition type; Obtain the first dredging index of the hydraulic dredging effect and the second dredging index of the mechanical dredging effect; Determine the first correlation value of the first dredging index and the flow velocity set, the current deposition type and the deposition volume and deposition form of each deposition type of each independent cutting block; Determine the second correlation value of the second dredging index and the flow velocity set, the current deposition type and the deposition volume and deposition form of each deposition type of each independent cutting block; According to the first correlation value and the second correlation value, a sediment control mode required by the corresponding independent cutting block is determined, and then a reservoir sediment control scheme of the reservoir is obtained.

6. The method of claim 5, wherein the method is characterized by, According to the first correlation value and the second correlation value, a sediment control mode required by the corresponding independent cutting block is determined, and then a reservoir sediment control scheme of the reservoir is obtained, including: The first correlation value of each independent cutting block is compared with the hydraulic regulation range for the first time, and the second correlation value is compared with the mechanical regulation range for the second time; When the first comparison result is in the recommended hydraulic control level, and the second comparison result is in the non-recommended mechanical control level, a hydraulic control label is set to the corresponding independent cutting block; When the first comparison result is in the non-recommended hydraulic control level, and the second comparison result is in the recommended mechanical control level, a mechanical control label is set to the corresponding independent cutting block; When the first comparison result is in the recommended hydraulic control level, and the second comparison result is in the recommended mechanical control level, a hydraulic and mechanical combined control label is set to the corresponding independent cutting block; When the first comparison result is not in the recommended hydraulic control level, and the second comparison result is not in the recommended mechanical control level, a pending label is set to the corresponding independent cutting block; According to all labels set by the corresponding model, the corresponding reservoir sediment control scheme is called from the label-scheme database.

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