Optimization method of junction dam slope

Abstract

The invention relates to the field of hub release structures, in particular to a hub dam slope optimization method. In order to guarantee the existing river flow state problem of an existing building-hub dam, reduce the influence of the building on a riverbed and the river and improve the safety degree of shipping and normal activities of surrounding people, it is necessary to conduct model test verification on hub and hydraulic design results, and a reasonable release building plane arrangement scheme is determined; and whether the improvement effect meets the design requirement or not is determined by improving the model structure and simulating and analyzing hydraulic parameters under different working conditions. According to the technical scheme, the model is established, hydraulic parameter analysis is carried out on different working conditions, and the model structure is further optimized and adjusted, so that a scientific experimental basis is provided for structure optimization of a real building, and the effect after optimization is ensured. The actual release structure can be better fused with the geographical environment, it is ensured that all hydraulic parameters are within the allowable range, and the effectiveness of the release structure is played to the maximum extent. And the flood discharge safety requirement is met.

Description

Technical Field

[0001] The invention relates to the field of hub water discharge structures, and in particular to a method for optimizing a hub dam side slope. Background Art

[0002] Discharge structures are important hydraulic structures that ensure the safety of water conservancy hubs and hydraulic structures and reduce flood disasters. They mainly include flood discharge gates and bottom holes for water discharge. By studying and analyzing the hydraulic characteristics of existing discharge structures, it is possible to provide certain experimental basis and technical support for the initial design of discharge structures. By setting up research and analysis under different working conditions, defects in the hydraulic elements of discharge structures can be discovered, and timely improvements and optimizations can be made.

[0003] Long-term cross-flow of water in the river has a negative impact on the physical form and ecological environment of the river. Cross-flow in the river will cause the river to swing or bend horizontally, which will affect the stability and function of the river. Cross-flow in the river will change the direction of the river, causing the river to bend or swing. Frequent cross-flow of the river will cause the riverbed to change constantly, affecting the life and production of residents along the river. The swing of the river will lead to the formation of a new river channel. The cross-circulation will cause the riverbed to be eroded and silted, forming deep grooves and shallows, changing the speed and direction of the water flow, affecting the self-purification capacity and ecological balance of the water body, and may lead to water quality degradation and ecological damage; affecting the stability of the riverbed.

[0004] The stability of the riverbed is essential to maintaining the natural form and function of the river. By taking appropriate anti-scouring measures, such as using Reno pads, shore cages, etc., the riverbed and bank slopes can be effectively protected to prevent these damages. Water conservancy projects on rivers, such as sluices and levees, are important facilities for flood control, irrigation, water supply, etc. If the riverbed is severely scoured, the structural safety of these projects will be threatened, which may lead to functional failure. Through reasonable anti-scouring design and measures, the stability of these projects can be enhanced and their service life can be extended. Through scientific and reasonable anti-scouring design and measures, the challenges brought by water scouring can be effectively responded to, and the long-term stability and safety of rivers and related facilities can be guaranteed.

[0005] The spillway structure of a hub is affected by the upstream bend river flow. The water flow on the dam is biased to the right bank. Under the verification and design conditions, there is a strong backflow vortex area near the right spillway inlet, and the flow state is relatively bad; the flooding degree of the water flow below the dam is large, and the water jump in each working condition occurs in the steep slope section of the lock chamber. Under the verification condition, the surface water splash of the water tongue after the jump has the risk of impacting the gate hinge. The water surface drops suddenly at the hub, and the head of the water jump is located in the steep slope section of the lock chamber under each working condition, resulting in a submerged water jump. In order to ensure the stability of navigation on the river and the safety of the building, it is necessary to optimize and improve the slope of the hub dam.

[0006] In summary, in order to ensure the rationality of the design of discharge structures, ensure the health and stability of the river ecosystem, and prevent the occurrence of the above-mentioned adverse situations, it is necessary to optimize the river flow state, optimize the riverbed anti-scouring structure, and improve the ecological function of the river, thereby promoting the sustainable development of the river ecosystem. Summary of the invention

[0007] The purpose of the present invention is to overcome the defects in the prior art and provide a method for optimizing the side slope of a hub dam.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] The present invention provides a method for optimizing the side slope of a hub dam, which specifically comprises the following steps:

[0010] S1. Modeling is done based on the topographic data of the hub dam, hub layout diagram and characteristic water level data. The model range is no less than 400m upstream of the hub dam and no less than 600m downstream of the hub dam;

[0011] S2. Conduct hydraulic parameter simulation tests, verify the data accuracy of the model simulation test based on the test data, and determine the specific optimization plan based on the test data;

[0012] S3. Improve the structure of the model in S1, and re-perform the hydraulic parameter test in step S2 to obtain optimized test data, and determine whether the optimized test data meets the requirements of various working conditions. If so, apply the improved solution to the hub dam. If not, continue to optimize the structure of the improved model and repeat the hydraulic parameter simulation test in step S2 until the test data meets the requirements.

[0013] After the construction of the discharge structure is completed, due to the combined influence of the terrain structure and tidal factors, there are complex water flow patterns that do not meet safety regulations. In order to ensure the existing flow pattern of the river for the existing building-hub dam, reduce the impact of the building on the riverbed and river, and improve the safety of navigation and normal activities of the surrounding people, it is necessary to conduct model tests to verify the hub and hydraulic design results, determine a reasonable plan layout for the discharge structure, and determine whether the improvement effect meets the design requirements through model structure improvement and simulation analysis of hydraulic parameters under different working conditions, so as to provide technical support for subsequent projects.

[0014] In the technical solution of the present invention, by establishing a model, hydraulic parameter analysis tests are conducted for different working conditions, and the model structure is further optimized and adjusted, which provides a scientific experimental basis for the structural optimization of actual buildings and ensures the effect after optimization. It enables the actual water discharge structure to be better integrated with the geographical environment, ensures that various hydraulic parameters are within the allowable range, and maximizes the effectiveness of the water discharge structure. It meets the safety requirements of flood discharge.

[0015] In the technical solution of the present invention, the flow pattern, flow velocity and other hydraulic elements of the hub dam are verified, and by improving the shape of the hub dam and re-verifying the hydraulic parameters, the lateral flow pattern and deviation of the independent hub dam under the working conditions of single use and combined use with adjacent buildings are analyzed and verified to ensure the rationality and comprehensiveness of the structural optimization.

[0016] As the preferred technical solution of your invention, the hydraulic simulation of the hub dam adopts the normal model, and the model scale is set to λ L =40, the model scale is determined according to the constraints such as the research content to be tested, test site conditions, minimum water depth and water flow Reynolds number.

[0017] As the preferred technical solution for your invention, the hydraulic simulation model of the hub dam needs to meet the following conditions: similar geometry, similar flow velocity, similar resistance, and similar flow.

[0018] Further preferably, the conditions that the hydraulic simulation model of the hub dam needs to meet also include:

[0019] a. The model water flow must be turbulent, that is, the model Reynolds number Re m = VR / v≥1000, where V represents the water velocity (m / s); R represents the hydraulic radius (m); v represents the water flow viscosity coefficient;

[0020] b. Minimum water depth restriction: To avoid the influence of surface tension, the minimum water depth of the test section of the hydraulic simulation model of the hub dam should not be less than 0.03m.

[0021] As a preferred technical solution of the present invention, the hydraulic simulation model of the hub dam includes an upper section, a flow-through structure, and a lower section. The model is terrain-modeled by a cross-section method, and the model cross-section is scaled down and made according to a plane scale and a vertical scale based on the measured riverbed terrain. The model is supplied with water through a water supply system, and the upper section of the model dam is provided with a flat water section and a water stabilizing gate. The sluice gate and the lower section of the model are simulated according to the actual terrain. In the model, the terrain surface is plastered with cement mortar, and the flow-through structure and the downstream sea section are made of plexiglass.

[0022] Preferably, the measurement and control instruments used in the model test include a Siemens electromagnetic flowmeter for controlling and measuring the flow rate; the tailgate water level is controlled and adjusted by a flap-type tailgate with a fine-tuning function, and the water level along the way is measured by a water level probe; the time-averaged pressure is measured by a pressure measuring tube; the pulsating pressure is measured by a resistive pulsating pressure sensor; and the flow velocity is measured by a new type of acoustic Doppler three-dimensional point flowmeter and propeller flowmeter produced in Norway.

[0023] As a preferred technical solution of the present invention, in step S2, before conducting the hydraulic parameter simulation test, the characteristic water level is selected. Specifically, the characteristic water level selection should be determined by comprehensively considering the flood control conditions of the hub dam, the sea floodplain section downstream of the hub dam, and the energy dissipation and anti-scouring control conditions of the riverbed. In the technical solution of the present invention, the characteristic water level includes three: verification P = 0.1%, design P = 1%, and energy dissipation and anti-scouring P = 2%.

[0024] The hydraulic parameters include: flow state, pressure distribution, water surface line, flow velocity distribution, pulsating pressure, energy dissipation effect under the gate and flow state of the power station water inlet.

[0025] Under the above three types of characteristic water level flows, the flow state of the spillway and the downstream apron section, the water surface line along the way, the bottom flow velocity along the way, the time-averaged pressure of the spillway bottom plate, and the pulsating pressure hydraulic parameters of the downstream apron section were tested respectively.

[0026] A slope optimization scheme is determined based on the test results of the above hydraulic parameters. Specifically, corresponding slope structure improvements are performed at the location where the flow problem occurs. The slope structure optimization methods include: expanding the slope line, adding diversion walls, adding retaining walls, and further determining the slope expansion range and / or the diversion wall shape and / or the retaining wall position elevation through the test data of step S2.

[0027] As a preferred technical solution of the present invention, the maximum navigable water level test condition is further added to carry out hydraulic parameter simulation test, and the upstream and downstream riverbed anti-scouring control condition is further tested for high tide level and low tide level respectively.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. In the technical solution of the present invention, by establishing a model, hydraulic parameter analysis tests are conducted for different working conditions, and the model structure is further optimized and adjusted, which provides a scientific experimental basis for the structural optimization of real buildings and ensures the effect after optimization. It enables the real water discharge buildings to be better integrated with the geographical environment, ensures that various hydraulic parameters are within the allowable range, and maximizes the effectiveness of the water discharge buildings. Meet the safety requirements of flood discharge.

[0030] 2. In the technical solution of the present invention, the flow pattern, flow velocity and other hydraulic elements of the hub dam are verified, and by improving the shape of the hub dam and re-verifying the hydraulic parameters, the lateral flow pattern and deviation of the independent hub dam under the working conditions of single use and combined use with adjacent buildings are analyzed and verified to ensure the rationality and comprehensiveness of the structural optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is the layout diagram of the spillway dam section;

[0032] Figure 2 This is the longitudinal section of the floodgate;

[0033] Figure 3 This is the longitudinal section of the bottom hole for water discharge;

[0034] Figure 4 is a water level-flow relationship diagram (where (a) represents the design water level-flow relationship diagram of the flood discharge gate, and (b) represents the design water level-flow relationship diagram of the bottom outlet for water discharge);

[0035] Figure 5 This is a schematic diagram of the model simulation range;

[0036] Figure 6 To verify the actual flow simulation process of the working condition;

[0037] Figure 7 It is a real-life picture of the flow simulation process for the design working condition;

[0038] Figure 8 This is a real-life diagram of the flow simulation process for energy dissipation and anti-collision conditions;

[0039] Fig. 9 This is a schematic diagram of the optimization scheme for the slope on the dam;

[0040] Fig.10 This is the improved real scene picture corresponding to the model;

[0041] Fig.11 A real-life picture of the flow pattern simulation process for checking the working condition after optimizing the solution;

[0042] Fig.12 A real-life picture of the flow pattern simulation process of the design working condition after the optimization scheme is implemented;

[0043] Fig.13 This is a real-life picture of the flow simulation process of the energy dissipation and anti-collision working condition after the optimization scheme;

[0044] Fig.14 This is a real-life picture of the flow simulation process for the highest navigation condition after the optimization scheme;

[0045] Fig.15 This is the cross-sectional layout diagram for flow velocity measurement on the dam;

[0046] Fig.16 Characteristic cross-sectional velocity distribution diagram on the dam for checking water level;

[0047] Fig.17 The characteristic cross-sectional velocity distribution diagram on the dam at the design water level;

[0048] Fig.18 This is a schematic diagram of the secondary optimization scheme for the dam slope;

[0049] Fig.19 It is a schematic diagram of the secondary optimization scheme of the model;

[0050] Fig. 20 This is a real-life picture of the flow simulation process on the dam under verification conditions;

[0051] Fig.21 This is a real-life picture of the flow pattern simulation process on the dam under the design conditions;

[0052] Fig. 22 This is a real-life picture of the flow pattern simulation process on the dam under the energy dissipation and anti-scouring conditions;

[0053] Fig.23 Provide a diagram for the model bed sand grade;

[0054] Fig.24 This is the effect diagram of the model's 4-hole local opening and sand interception;

[0055] Fig.25 This is the model 7-hole local drilling sand interception effect diagram;

[0056] Markings in the figure:

[0057] 1-flood discharge gate, 2-bottom discharge hole, 3-pivot dam, 31-lock chamber section, 32-steep slope section, 33-sea floodplain section. DETAILED DESCRIPTION

[0058] The present invention is further described in detail below in conjunction with specific embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0059] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating the orientation or position relationship such as "up", "down", "left", "right", "center", "inside", "outside", etc. are all based on the expression of the orientation or position relationship shown in the drawings, or are the orientation or position relationship when the invented product / equipment / device is usually used. These terms of orientation or position relationship are only for the convenience of describing the scheme of the present invention or simplifying the description in the specific embodiments, so as to facilitate the technicians to quickly understand the scheme, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific position relationship, and therefore cannot be understood as a limitation on the present invention.

[0060] Example 1

[0061] The optimization method of the hub dam slope described in the present invention is mainly applied to the Qingnian hub of the Pinglu Canal Project, that is, the hydraulic simulation model in this embodiment is established based on the Qingnian hub discharge structure as a prototype.

[0062] Qingnian Hub is the last step of Pinglu Canal. The river channel in this section is narrow and winding, the width of the main river channel is only more than 100 meters, the river bank is covered with low mountains and gullies, and the terrain is complex. Affected by factors such as river flow and geology, the discharge structure is arranged in the curved river section, the length of the upstream and downstream straight sections is insufficient, and the downstream of the sluice is about 20 kilometers away from the sea. The superimposed tidal factors have a complex flow pattern. According to the requirements of the specification, the hub layout and hydraulic design results should be verified by hydraulic model tests. Through physical model tests, a reasonable plan layout plan for the discharge structure is verified and determined to provide technical support for engineering construction.

[0063] like Figure 1-Figure 25 As shown, the optimization scheme of the present invention comprises the following steps:

[0064] S1. Determine the simulation range and make a model based on the topographic data of the hub dam 3, the hub layout diagram and the characteristic water level data: the model range is no less than 400m upstream of the hub dam to no less than 600m downstream of the hub dam;

[0065] The Youth Hub water discharge structure is mainly arranged with seven-hole flood discharge gate 1 and one-hole bottom discharge hole 2. The hub dam 3 is 122m long and the top elevation of the hub dam 3 is 17.50m. The plane layout and longitudinal section of the water discharge structure are shown in Figure 1 to Figure 3 .like Figure 2-3 As shown, from left to right in the figure, it is from the upstream of the dam to the downstream of the dam, wherein the hub dam 3 includes a lock chamber section 31, a steep slope section 32 and a sea flood section 33 in sequence.

[0066] The Youth Hub uses Luwu as the reference station, and transplants it according to the first power of the area ratio, with a rainfall correction index of 1.0. The design annual runoff results of the dam site are shown in Table 1, and the design flood results of the Youth Hub dam site are shown in Table 2.

[0067] Table 1 is the calculation results of the annual natural average flow frequency analysis at the dam site

[0068]

[0069] Table 2 Youth Hub Design Flood Results

[0070] frequency 0.1％ 1％ 2％ 5％ <![CDATA[Inflow rate (m 3 / s)]]> 9530 5890 4840 3490 <![CDATA[Outflow rate (m 3 / s)]]> 7510 5090 4310 3300

[0071] The main structures such as the Youth Hub Dam and the flood discharge gate adopt the verification flood recurrence period of 1000 years and the peak flow Ω=7510m / s; the design flood recurrence period is 100 years and the peak flow is 2-5090m' / s. The design standard for energy dissipation and anti-scouring of the downstream of the discharge structure is a flood of 50 years, and the flood discharge gate outlet sea flood section and downstream river channel are designed according to the energy dissipation and anti-scouring standards. The design standard for anti-scouring of the upstream river channel is a flood of 20 years.

[0072] The normal water storage level of the Youth Hub Dam is 8.70m, the upstream design flood level is 12.01m, the verification flood level is 15.17m, the design maximum navigable water level is 9.32m, and the design minimum navigable water level is 8.00m; the downstream design maximum navigable water level is 6.50m, and the design minimum navigable water level is -1.62m. Considering the influence of high and low tide levels downstream of the hub, the characteristic water level of the Youth Hub is shown in Table 3-4.

[0073] Table 3 summarizes the characteristic water levels at low tide downstream of the Youth Hub

[0074]

[0075] Table 4 summarizes the characteristic water levels of the high tide downstream of the Youth Hub

[0076]

[0077] Furthermore, the design water level and flow relationship of the flood discharge gate 1 and the bottom outlet was studied, see Figure 4 ; The relationship between the water level and flow rate downstream of the Youth Hub Dam also takes into account different tidal level combinations.

[0078] Taking into account the actual geological conditions of the river channel downstream of the Youth Hub, the rock mass is slightly weathered and relatively broken, and the comprehensive bedrock anti-impact flow velocity is taken as 2.5 to 3.0 m / s.

[0079] Based on the above data information, the normal model is used for hydraulic simulation of the discharge structure. According to the experimental research content, the test site conditions, minimum water depth, water flow Reynolds number and other constraints are comprehensively considered, and the model scale is set to λ L =40, the hydraulic simulation model of the hub dam needs to meet the following conditions: similar geometry, similar flow velocity, similar resistance, and similar flow.

[0080] Specific, geometric similarity: λ L＝ λ H =L p / L m =40

[0081] In the above formula, λ L represents the plane scale; λ H Indicates the vertical scale; L p Indicates the prototype length, L m Indicates the length of the model.

[0082] Flow rate similarity: λ v =λ L 1 / 2 =6.325, where λ v Indicates flow rate ratio.

[0083] Resistance similarity: λ n =λ L1 / 6 =1.849In the formula, λ n Indicates the roughness coefficient ratio.

[0084] Traffic similarity: λ Q =λ L 1 / 2 =10119In the formula, λ Q Indicates flow rate ratio.

[0085] To be more specific, the conditions that the hydraulic simulation model of the hub dam needs to meet also include:

[0086] a. The model water flow must be turbulent, that is, the model Reynolds number Re m = VR / v≥1000, where V represents the water velocity (m / s); R represents the hydraulic radius (m); v represents the water flow viscosity coefficient;

[0087] b. Minimum water depth restriction: To avoid the influence of surface tension, the minimum water depth of the test section of the hydraulic simulation model of the hub dam should not be less than 0.03m.

[0088] According to the topographic data of the hub river section, and considering the similarity of the flow conditions of the model inlet and outlet, the flow pattern in the test section is guaranteed not to be affected. The research scope of the physical model is 510m upstream of the dam site to 650m downstream of the dam site, and the length of the simulated river section is about 1.16km. Figure 5 shown.

[0089] The hydraulic simulation model of the hub dam includes the upper section of the dam, the flow-through structure, and the lower section of the dam. The model is modeled by the cross-section method, and the model section is scaled down according to the measured riverbed terrain in the plane scale and the vertical scale. The model is supplied with water through the water supply system. The river channel in the upper section of the model dam is provided with a flat water section and a water stabilizing gate. The sluice gate and the river channel in the lower section of the dam are simulated according to the actual terrain. In the model, the terrain surface is plastered with cement mortar, and the flow-through structure and the downstream sea section are made of plexiglass. The measurement and control instruments used in the model test include Siemens electromagnetic flowmeters for controlling and measuring flow; the tailgate water level is controlled and adjusted by a flap tailgate with a fine-tuning function, and the water level along the way is measured by a water level probe; the time-averaged pressure is measured by a pressure tube; the pulsating pressure is measured by a resistive pulsating pressure sensor; the flow velocity is measured by a new type of acoustic Doppler three-dimensional point velocity meter and a propeller velocity meter produced in Norway.

[0090] In the optimization method of this embodiment, the hydraulic parameters do not meet the design requirements mainly because the structure of the slope is unreasonable. Therefore, the hydraulic parameters can be adjusted to a normal range by optimizing the slope structure. Therefore, when conducting simulation tests through the model, the hydraulic characteristic parameter information is mainly observed and counted.

[0091] S2. Conduct hydraulic parameter simulation tests, verify the data accuracy of the model simulation test based on the test data, and determine the specific optimization plan based on the test data;

[0092] Taking into account the flood control conditions of the hub and the energy dissipation and anti-scouring control conditions of the downstream sea floodplain and riverbed, three typical characteristic water levels of verification (P = 0.1%), design (P = 1%), and energy dissipation and anti-scouring (P = 2%) were selected for testing, as shown in Table 5. The flow pattern, water surface line along the way, bottom flow velocity along the way, time-averaged pressure of the bottom plate of the flood discharge gate, and pulsating pressure of the bottom plate of the downstream sea floodplain section were tested at various flow levels. The water level boundary control positions above and below the model dam are 400m above the dam and 600m below the dam, respectively, and the water level is controlled according to Table 5.

[0093] Table 5 shows the test conditions of the flood discharge gate

[0094]

[0095] Since the purpose of the optimization of the dam slope is mainly to improve the flow pattern of the river channel, the remaining hydraulic parameters such as the water surface line along the way, the flow velocity along the bottom, the time-averaged pressure of the bottom plate of the flood discharge gate, and the pulsating pressure of the bottom plate of the downstream seafloor section are mainly used to verify the simulation accuracy of the model. This embodiment does not elaborate on the test process and results of the above hydraulic parameters.

[0096] S3. Improve the structure of the model in S1, and re-perform the hydraulic parameter test in step S2 to obtain optimized test data, and determine whether the optimized test data meets the requirements of various working conditions. If so, apply the improved solution to the hub dam. If not, continue to optimize the structure of the improved model and repeat the hydraulic parameter simulation test in step S2 until the test data meets the requirements.

[0097] In S3, the target to be optimized of the hub dam is determined based on the hydraulic parameter data of step S2, wherein the hydraulic parameter data includes an area where the flow pattern passes through statistically abnormal flow patterns, and the structure of the hub dam slope is optimized for the area.

[0098] In this embodiment, in order to improve the river flow pattern in the Qingnian Hub Dam area, the slope scheme is designed mainly according to the flow pattern. The hydraulic parameters include flow pattern, specifically including the flow pattern above the dam, the flow pattern of the lock chamber section, the flow pattern below the dam, and the flow pattern of the power station water inlet.

[0099] The flow patterns at the dam inlet, lock chamber and sea floodplain under the dam under various working conditions are as follows: Figure 6-8As shown. Specifically, it can be seen from the figure that: from the perspective of river channel morphology, the dam is an "S"-shaped bend. Affected by the river flow, the upper bend is longer and the top of the bend is on the right bank; the lower bend is shorter and the top of the bend is on the left bank. Affected by the river flow, the water flow in the upper bend has insufficient adjustment distance after passing through the lower bend, and the mainstream is biased toward the stone bank. Along the cross-sectional direction, the water level is higher on the right and lower on the left, and the lateral water flow is unevenly distributed. Checking and designing flood conditions, a strong backflow vortex area is formed at the right inlet of the flood discharge gate, and the flow state is relatively bad.

[0100] Lock chamber section: Check flood conditions. Water jump occurs in the steep slope section of the lock chamber. The jump head is close to the gate hinge. The water splash on the surface of the water tongue has the risk of impacting the gate hinge. As the flood flow decreases, the water jump head gradually moves downward, and the risk of the hinge position decreases.

[0101] Below the dam: The water flow inundation degree below the dam is relatively large, and the water flow in the Haiman section is relatively stable, with no obvious adverse flow state.

[0102] Based on the flow problems in the above-mentioned areas, the side slopes of the hub dam are structurally modified respectively: the slope structure optimization methods include: expanding the slope line, adding diversion walls, adding retaining walls, and further determining the slope expansion range and / or the shape of the diversion wall and / or the position elevation of the retaining wall through the test data of step S2.

[0103] like Fig. 9 As shown, the green line is the original slope structure, and the pink line is the improved slope structure.

[0104] Based on the design plan, the specific optimization measures are:

[0105] The bottom slope line of the right bank of the dam is expanded outward, and a vertical diversion wall is added with a length of 32m and a top elevation of 15.50m;

[0106] At the second bend on the left bank of the dam, the slope expands outward, the slope excavation range is expanded, and the turning radius is increased.

[0107] In addition, a retaining wall is added behind the right side slope of the downstream seawall section, with the top elevation of the wall at 1.00m. Fig. 9 (pink line in the figure), see the model modification Fig.10 .

[0108] In this embodiment, the hydraulic parameter experiment is re-performed using the model with improved structure. Specifically, the hydraulic parameters mainly focus on the flow state.

[0109] On the basis of the design scheme test conditions, considering the upstream riverbed anti-scouring control standard, the maximum navigable water level (P = 5%) test condition is added: considering the impact of downstream tidal changes on the riverbed and riverbank slope lining range below the dam, the upstream and downstream riverbed anti-scouring control conditions are tested for high tide and low tide respectively. The test conditions are shown in Table 6. It should be pointed out that the water level of the control boundary 400m above the model dam and 600m below the dam is controlled according to the water level at the corresponding position in Table 3 and Table 4.

[0110] Table 6 is a summary of the test conditions for the optimization scheme on the dam

[0111]

[0112] The flow distribution under each working condition is as follows: Figure 11 to Figure 14 The outward expansion of the left and right bank slopes and the addition of a vertical diversion wall on the right bank can effectively adjust the water flow on the dam, weaken the mainstream deviation, and significantly reduce the backflow phenomenon on the right side of the flood discharge gate inlet. Under the verification and design conditions, the scope of the backflow vortex area on the right bank of the dam is significantly reduced, and the cross-flow situation in the river channel is significantly improved.

[0113] Furthermore, the cross flow on the dam was also tested. Along the centerline of the flood discharge gate, flow velocity measurement sections were arranged at 20m, 60m, 100m, 150m, and 200m on the dam, with measurement points spaced 10m to 20m apart. The flow velocity measurement sections on the dam are arranged as follows: Fig.15 The surface velocity and bottom velocity distribution of each typical section under the check water level and design water level are shown in Fig.16 , Fig.17 The corresponding measuring point data are shown in Table 7a, Table 7b, and Table 8. Affected by the river flow above the dam, the mainstream is slightly biased to the left bank at 200m above the dam, and slightly biased to the right bank at 20m above the dam. Under the verification condition, the maximum surface velocity at the hub is 7.30m / s; under the design condition, the maximum surface velocity at the hub is 5.40m / s.

[0114] Table 7a shows the characteristic cross-sectional flow velocity values ​​on the dam (calibrated water level)

[0115]

[0116] Table 7b shows the characteristic cross-sectional flow velocity values ​​on the dam (calibrated water level)

[0117]

[0118] Table 8 shows the characteristic cross-sectional flow velocity values ​​on the dam (design water level)

[0119]

[0120] It can be seen from the figure and table that after the optimization of the dam layout (the slopes on the left and right banks are expanded and a right-angle diversion wall is added on the right bank), the water flow deviation on the dam is significantly improved. Under the verification and design conditions, the range of the backflow vortex area on the right bank of the dam is significantly reduced. The mainstream on the dam is still slightly biased to the right bank. Under the verification and design conditions, the maximum surface velocity of the transverse section at 20m above the dam is 7.30m / s and 5.40m / s respectively.

[0121] According to the new simulation data and water flow conditions, further improvements are needed. On the basis of the first optimization, the connection form between the right bank right-angle diversion wall and the bank slope is further adjusted, the right bank right-angle diversion wall on the dam is adjusted to an eight-shaped diversion wall structure (wall top elevation 12.50m), and a sand barrier is added in front of the powerhouse. Figure 18-19 shown.

[0122] Continue to conduct flow test on the second optimized model. Figure 20-22 After the right-angle diversion wall on the right bank was adjusted to an eight-shaped diversion wall structure, the flow pattern of the incoming flow on the dam was further improved under the design and energy dissipation and anti-scouring conditions, and the water flow connection was smoother. Under the verification condition, because the water level was higher than the top elevation of the diversion wall, waterlogging occurred at the intersection of the water flow along the right bank slope and the squeezed water flow along the right side of the lateral direction.

[0123] Furthermore, the effect of the sand barrier was tested by selecting a flood flow of 890m with a return period of 2 years (P = 50%). 3 / s (normal water level on the dam is 8.7m) to test the sand interception effect of the newly added sand interception bank. Simulate the bed sand morphology of the bed load, and select the fine sand gradation that can sink to the bottom and start to move according to the characteristics of the bed load for testing. Use the existing graded sediment in the laboratory for simulation. The model sand gradation is shown in Table 9 and Fig.23 , where d 50 About 0.183mm.

[0124] Table 9 shows the model sand gradation

[0125] <![CDATA[Prototype d p (mm)]]> 6.68 7.68 14.72 29.4 <![CDATA[Model d m (mm)]]> 0.167 0.192 0.368 0.735 P(％) 0 6.11 79.37 99.79

[0126] Two gate hole opening combinations were selected: (1) 4 holes were opened, with an opening height of 1.90 m; (2) 7 holes were opened, with an opening height of 0.93 m.

[0127] The results of the sand flushing test on the dam are shown in Fig.24 , Fig.25 It can be seen that under different opening combinations of the spillway, the sediment on the dam will not accumulate in front of the sand barrier or go over the top of the sand barrier, and the sediment can be smoothly discharged downstream from the spillway along with the water flow. The effect of the sand barrier is obvious.

[0128] The diversion wall on the right bank of the dam has been further optimized, from a right-angle diversion wall to an eight-shaped diversion wall structure, making the water flow smoother and the flow pattern on the dam further improved. The sand barrier in the forebay of the powerhouse has a significant effect and can effectively prevent sediment from entering the forebay of the power station.

[0129] The structural optimization scheme of the model hub dam can be directly applied to the slope of the Qingnian hub dam, and the slope optimization effect is basically the same as that of the model test.

[0130] In this embodiment 1, the hydraulic parameters are verified by the model and the slope of the model is adjusted at least once for the flow state problem. Each adjustment requires retesting the hydraulic parameters to further refine the optimization scheme and ultimately form the best slope optimization scheme.

[0131] In the technical solution of the present invention, hydraulic parameters are analyzed through modeling verification, the structural defects of the water discharge structure are obtained, and the structure is further optimized on the basis of the existing structure, and the flow state of the river is adjusted through structural optimization, thereby improving the structural safety and ensuring the long-term stability and safety of the river and related facilities.

[0132] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for optimizing the slope of a hub dam, characterized in that: The steps include: S1. Modeling is done based on the topographic data of the hub dam, hub layout diagram and characteristic water level data. The model range is no less than 400m upstream of the hub dam and no less than 600m downstream of the hub dam; S2. Conduct hydraulic parameter simulation tests, verify the data accuracy of the model simulation test based on the test data, and determine the specific optimization plan based on the test data; S3. Improve the structure of the model in S1, and re-perform the hydraulic parameter test in step S2 to obtain optimized test data, and determine whether the optimized test data meets the requirements of various working conditions. If so, apply the improved solution to the hub dam. If not, continue to optimize the structure of the improved model and repeat the hydraulic parameter simulation test in step S2 until the test data meets the requirements.

2. The method for optimizing the side slope of a pivot dam according to claim 1, characterized in that: The normal model is used for hydraulic simulation of the hub dam, and the model scale is determined according to the research content to be tested, test site conditions, minimum water depth and flow Reynolds number constraints.

3. The method for optimizing the side slope of a pivot dam according to claim 2, characterized in that: The hydraulic simulation model of the hub dam needs to meet the following conditions: similar geometry, similar flow velocity, similar resistance, and similar flow.

4. A method for optimizing the side slope of a pivot dam according to any one of claims 2-3, characterized in that: The conditions that the hydraulic simulation model of the hub dam needs to meet also include: a. The model water flow must be turbulent, that is, the model Reynolds number Re m = VR / v≥1000, where V represents the water velocity (m / s); R represents the hydraulic radius (m); v represents the water flow viscosity coefficient; b. Minimum water depth restriction: To avoid the influence of surface tension, the minimum water depth of the test section of the hydraulic simulation model of the hub dam should not be less than 0.03m.

5. The method for optimizing the side slope of a pivot dam according to claim 4, characterized in that: The hydraulic simulation model of the hub dam includes an upper section, flow-through structures, and a lower section. The model is terrain-modeled by the cross-section method, and the model cross-section is scaled down and made according to the plane scale and vertical scale based on the measured riverbed terrain; the model is supplied with water through a water supply system, and the river channel in the upper section of the model dam is provided with a flat water section and a water-stabilizing gate, and the sluice gate and the river channel in the lower section of the model are simulated according to the actual terrain. In the model, the terrain surface is plastered with cement mortar, and the flow-through structures and the downstream sea section are made of plexiglass. The model also includes a measurement and control system, which is used to measure, control and adjust hydraulic parameters.

6. The method for optimizing the side slope of a pivot dam according to claim 1, characterized in that: In step S2, before conducting the hydraulic parameter simulation test, the characteristic water level is selected. The characteristic water level selection should be determined by comprehensively considering the flood control conditions of the hub dam, the sea floodplain section downstream of the hub dam, and the energy dissipation and anti-scouring control conditions of the riverbed. The characteristic water levels include verification P=0.1%, design P=1% and energy dissipation and anti-scouring P=2%. Each characteristic water level flow condition requires hydraulic parameter testing.

7. A method for optimizing the side slope of a pivot dam according to claim 6, characterized in that: In S3, the target to be optimized of the hub dam is determined based on the hydraulic parameter data of step S2, wherein the hydraulic parameter data includes an area where the flow pattern passes through statistically abnormal flow patterns, and the structure of the hub dam slope is optimized for the area.

8. The method for optimizing the side slope of a pivot dam according to claim 7, characterized in that: The hydraulic parameters include flow states, specifically flow states above the dam, flow states below the dam, and flow states at the water inlet of the power station.

9. The method for optimizing the side slope of a pivot dam according to claim 1, characterized in that: The slope structure optimization method includes: expanding the slope line, adding diversion walls, adding retaining walls, and further determining the slope expansion range and / or the diversion wall shape and / or the retaining wall position elevation through the test data of step S2.

10. A method for optimizing the side slope of a pivot dam according to claim 9, characterized in that: When the hydraulic parameter simulation test is performed again on the adjusted model, the highest navigable water level is further added as a test condition, and the highest navigable water level is P=5%.

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