Flaring pier of flood discharge gate and design method of flaring pier

Abstract

The invention relates to the field of flood discharge, in particular to a flaring pier of a flood discharge gate and a design method thereof, and the design method comprises the following steps: S1, establishing a single-hole mathematical model of the flood discharge gate; determining structural design parameters of the flaring pier, wherein the structural design parameters comprise a tail pier type, an orifice width before contraction, a pier tail break angle, a contraction ratio, an outlet width, a contraction section length and a pier top elevation; s2, the structural design parameters are combined, a plurality of flaring pier design schemes are formed, each design scheme is input into the mathematical model for calculation, and calculation results are obtained; and S3, the impact trunnion risk value k serves as a judgment condition to determine the optimal design scheme of the flaring pier, k = f (the water jump head position, the head water depth, the maximum near-bottom flow velocity of the lock chamber, the discharged flow and the water surface line of the lock chamber), and f serves as a function. According to the method, the calculation results of various design schemes are quickly obtained by establishing the flood discharge gate single-hole mathematical model, and the optimal structural form of the flaring pier can be quickly and accurately determined by taking the impact trunnion risk value k as a judgment condition.

Description

Technical Field

[0001] The invention relates to the field of flood discharge, and in particular to a wide tail pier of a flood discharge gate and a design method thereof. Background Art

[0002] Flood discharge gates are working gates used to discharge flood water and regulate and control the water level of reservoirs. They can release excess water when the water level is too high to ensure the safety of reservoirs or rivers, effectively prevent floods, and avoid disasters causing significant losses to people's lives and property. At the same time, flood discharge gates can also regulate water levels, maintain the stability of water sources and the cleanliness of water quality, and improve production efficiency and agricultural production capacity.

[0003] The flood discharge of low-head riverbed hub is large, and the flooding degree below the gate is large. Water jump may occur in the steep slope section of the gate chamber, and 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, which may be detrimental to the stability of the hinge structure.

[0004] The wide tail pier is to widen the tail of the gate pier, narrow the outlet of the gate chamber, and cause the water flow behind the pier to shrink horizontally, forming a narrow and high "1"-shaped three-dimensional contraction jet to achieve the purpose of enhancing energy dissipation, erosion reduction and corrosion prevention. It uses the wide tail pier to form a weir crest contraction jet, forming a violently aerated three-dimensional water jump in the energy dissipation pool, thereby greatly improving the energy dissipation rate. By changing the structural form of the wide tail pier, it helps the water flow to transition more smoothly, reduce the jumping and splashing of the water tongue, and thus reduce the risk of the water splash on the surface of the water tongue impacting the gate hinge. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a wide tail pier of a flood discharge gate and a design method thereof.

[0006] In a first aspect, the present invention provides a design method for a wide tail pier of a flood discharge gate, comprising the following steps:

[0007] S1: Establish a mathematical model of a single hole of the flood discharge gate; determine the structural design parameters of the wide tail pier, including the tail pier type, hole width before contraction, pier tail angle, contraction ratio, outlet width, contraction section length and pier top elevation;

[0008] S2: Combining the structural design parameters to form multiple wide tail pier design schemes, and inputting each design scheme into the mathematical model for calculation to obtain the calculation results;

[0009] S3: The optimal design scheme of the wide tail pier is determined by taking the impact hinge risk value k as the judgment condition, k = f (water jump head position, jump head water depth, maximum bottom flow velocity of the lock chamber, discharge flow, lock chamber water surface line), where f is a function.

[0010] The present invention provides a design method for a wide tail pier of a flood discharge gate. By establishing a single-hole mathematical model of the flood discharge gate, the law of hydraulic jump variation can be studied, and the calculation results of various design schemes can be quickly obtained. By further evaluating the calculation results, the optimal design scheme of the wide tail pier is determined by taking the impact support hinge risk value k as a judgment condition, and the optimal structural form of the wide tail pier can be determined quickly and accurately.

[0011] Preferably, in S3, the expression of the impact hinge risk value k is as follows:

[0012] k = n1f1 (water jump head position) + n2f2 (jump head water depth) + n3f3 (maximum bottom flow velocity of the lock chamber)

[0013] +n4f4(discharge flow)+n5f5(water surface line of lock chamber);

[0014] In the formula, f1, f2, f3, f4, and f5 are functions respectively, n1, n2, n3, n4, and n5 are coefficients respectively, and n1+n2+n3+n4+n5=1.

[0015] Preferably, in S3, n1≥n2>n3≥n4≥n5.

[0016] Preferably, in S1, the model range of establishing the single-hole mathematical model of the flood discharge gate is from l1m above the dam to l2m below the dam, and l2>l1.

[0017] Preferably, in S1, when establishing the mathematical model of a single hole of the flood discharge gate, the upstream boundary adopts the water level boundary, and the downstream boundary adopts the water level boundary.

[0018] Preferably, in S1, the tail pier types include rectangular, Y-shaped and X-shaped.

[0019] Preferably, in S1, the structural design parameters also include whether the bottom is hollow and the hollow height of the bottom.

[0020] Preferably, the numerical value of each of the structural design parameters is initially determined in a range according to theoretical calculations.

[0021] Preferably, the numerical value of each of the structural design parameters varies uniformly.

[0022] In a second aspect, the present invention provides a flood discharge gate designed by using any of the design methods for a wide tail pier of a flood discharge gate.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention provides a wide tail pier of a flood discharge gate and a design method thereof. By establishing a single-hole mathematical model of the flood discharge gate, the law of hydraulic jump changes can be studied, and the calculation results of various design schemes can be quickly obtained. By further evaluating the calculation results, the optimal design scheme of the wide tail pier is determined by taking the impact hinge risk value k as a judgment condition, and the optimal structural form of the wide tail pier can be quickly and accurately determined. The wide tail pier of the flood discharge gate after design optimization can effectively reduce the risk of water splashes on the surface of the water tongue impacting the gate hinge, and ensure the safe operation of the hub flood discharge gate. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the floor plan of the discharge structure.

[0026] Figure 2 This is the longitudinal section of the flood discharge gate.

[0027] Figure 3 This is a schematic diagram showing the risk of water splashing on the surface of the water tongue impacting the gate hinges.

[0028] Figure 4 Schematic diagram of the mathematical model of a single hole of a flood discharge gate.

[0029] Figure 5 This is the boundary condition diagram of the mathematical model of the flood discharge gate.

[0030] Figure 6 This is a schematic diagram of the wide tail pier structure.

[0031] Figure 7 This is the plan layout of the wide tail pier (unit: m).

[0032] Figure 8 This is a schematic diagram of the flow field in the lock chamber of the wide tail pier scheme.

[0033] Fig. 9 This is the water surface line along the wide tail pier scheme.

[0034] Fig.10 The figure is the recommended parameter diagram of wide tail pier shape (unit: m). DETAILED DESCRIPTION

[0035] 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.

[0036] 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.

[0037] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding devices / components / elements are required to be absolutely horizontal or vertical or overhanging or parallel, but may be slightly tilted or have deviations. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but may be slightly tilted. Alternatively, it can be simplified to mean that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, and more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the scheme of the present invention.

[0038] In addition, the expressions “first”, “second”, “third”, etc., which appear in the terms, are merely used to distinguish the description of the same or similar components and should not be understood as emphasizing or implying the relative importance of specific components.

[0039] In addition, in the description of the embodiments of the present invention, "several", "plurality" and "a number" represent at least 2. It can be any number such as 2, 3, 4, 5, 6, 7, 8, 9, and even more than 9.

[0040] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / restricted, the terms "set", "install", "connect", "connected", "provided with", "laid", and "arranged" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, and can be welding, riveting, bolting, threading, and other commonly used connection means in the field. This connection can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements.

[0041] Example 1

[0042] The main layout of the water discharge structure of a hub is 7 flood discharge gates and 1 bottom discharge hole. The dam is 122m long and the dam top elevation is 17.50m. The plan layout and longitudinal section of the water discharge structure are shown in Figure 1-2 shown.

[0043] The 7-hole flood discharge gate is arranged in the main river channel, with a single hole net width of 13.0m and a total front width of 116.0m. The gate pier is split, with the left pier thickness of 2.0m, the middle pier thickness of 3.5m, and the right pier thickness of 2.0m. The width of a single hole is 16.50m. The flood discharge gate top elevation is 17.50m, the weir top elevation is 1.00m, and the gate chamber length along the water flow direction is 35.0m. From upstream to downstream, a flat inspection door and an arc-shaped working door are set in sequence. The inspection door is opened and closed by a mobile gantry crane on the dam top, and the working door is opened and closed by a hydraulic hoist. A 4.8m wide traffic bridge is set on the upstream side of the gate top, and the traffic bridge top elevation is 17.50m. Two gate top gantry track beams are arranged next to the traffic bridge, and oil pipe cable box beams are arranged on the downstream side. The flood discharge gate weir type adopts a wide top weir, and the weir top elevation is 1.00m. Behind the flood discharge gate, it is connected to the seafloor through a 1:4 slope. The seafloor is 100m long and a riprap anti-scour trough is set at the end.

[0044] The hub is a low-head riverbed hub with a large flood discharge and a large flood depth below the gate. Under the verification condition, the water jump occurs in the steep slope section of the gate chamber, and 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, which may be detrimental to the stability of the hinge structure. Figure 3 shown.

[0045] Consider optimizing the lock chamber structure and push the hydraulic jump location downstream, thereby reducing the water depth at the hinge location.

[0046] A design method for a wide tail pier of a flood discharge gate comprises the following steps:

[0047] S1: Establish a single-hole mathematical model of the flood discharge gate, determine the boundary conditions and initial water flow conditions of the mathematical model, and perform numerical simulation calculations.

[0048] The mathematical model of a single hole of a flood discharge gate is as follows Figure 4 The model study range is from 10m above the dam to 120m below the dam. The upstream boundary uses the water level boundary and the water level is set to 15.17m. The downstream boundary uses the water level boundary and the water level is set to 11.74m. The mathematical model boundary conditions and initial water flow conditions are set in Figure 5 .

[0049] Determine the structural design parameters of the wide tail pier, including the tail pier type, the width of the opening before contraction, the pier tail angle, the contraction ratio, the outlet width, the contraction section length and the pier top elevation, etc. Further preferably, the structural design parameters also include whether the bottom is hollow and the bottom hollow height.

[0050] S2: Combine the structural design parameters to form multiple wide tail pier design schemes, and input each design scheme into the mathematical model for calculation to obtain the calculation results.

[0051] The numerical value of each structural design parameter can be large or small, and the preliminary range is determined according to theoretical calculation. For example, the body parameters of wide tail piers of some existing low head projects are shown in Table 1 and Figure 6 shown.

[0052] Table 1 Body parameters of wide tail piers in typical projects

[0053]

[0054] In the table, the contraction ratio ε = B / B; the initial inflection point position parameter = X / Hd.

[0055] Based on the layout characteristics of a flood discharge gate at a certain hub and referring to relevant engineering experience, a wide tail pier shape was designed. Two wide tail pier inflection points were initially selected: (1) According to the actual layout of the project, in order to ensure a smooth lateral transition of the water flow, the wide tail pier inflection point was selected at the point where the width of the original gate wall changes, 18.33m away from the end of the gate pier; (2) According to engineering experience, the wide tail pier inflection point was selected at 8m away from the end of the gate pier, the contraction ratio was selected as 0.5, and the corresponding pier tail inflection angle was 20°. The plan layout of the two wide tail pier shapes is shown in the figure. Figure 7 shown.

[0056] The numerical value of each of the structural design parameters can change uniformly or non-uniformly. For example, the change in the pier top height can be 0.5m as a change increment. The heights of the flood discharge gate pier tops are: 0.5m, 1m, 1.5m, 2m..., or it can be nonlinear, such as 1m, 2m, 3m, 5m.

[0057] The calculation conditions and statistical results are shown in Table 2. The traditional straight-wall wide tail pier is suitable for flood discharge in cases of high tailwater and large single width. When the tailwater depth is small or the flood discharge is small, water concentration is likely to occur, which will cause the impact pressure of the downstream seafloor section to increase sharply. In order to increase the applicability of the wide tail pier structure to the downstream discharge flow, the X-type wide tail pier structure is also studied.

[0058] Table 2 Calculation conditions and statistical results of the wide tail pier scheme

[0059]

[0060] S3: The optimal design scheme of the wide tail pier is determined by taking the impact hinge risk value k as the judgment condition, k = f (water jump head position, jump head water depth, maximum bottom flow velocity of the lock chamber, discharge flow, lock chamber water surface line), where f is a function.

[0061] The present invention selects the water jump head position, the jump head water depth, the maximum bottom flow velocity of the lock chamber, the discharge flow, and the lock chamber water surface line as influencing factors affecting the impact hinge risk value k. These influencing factors can accurately describe the impact hinge risk value.

[0062] Next, the most important influencing factor is identified in the calculation of the impact hinge risk and assigned the largest coefficient. By setting different importance levels, the risk value k of the impact hinge can be obtained more accurately.

[0063] In S3, the expression of the impact hinge risk value k is as follows:

[0064] k = n1f1 (water jump head position) + n2f2 (jump head water depth) + n3f3 (maximum bottom flow velocity of the lock chamber)

[0065] +n4f4(discharge flow)+n5f5(water surface line of lock chamber);

[0066] In the formula, f1, f2, f3, f4, and f5 are functions, n1, n2, n3, n4, and n5 are coefficients, and n1+n2+n3+n4+n5=1. n1, n2, n3, n4, and n5 represent the importance of different influencing factors. The values ​​of n1, n2, n3, n4, and n5 can be different, and the larger the value, the more important it is.

[0067] Furthermore, n1≥n2>n3≥n4≥n5. That is, the influence and importance of the water jump head position and the water depth of the jump head are usually greater than the influence and importance of the maximum bottom flow velocity, discharge flow and water surface line of the lock chamber.

[0068] The longitudinal flow field results under various schemes are as follows Figure 8 As shown, the water surface line along the way is as follows Fig. 9 According to the settlement results, adding a wide tail pier structure has basically no effect on the flow rate. The optimal design scheme of the wide tail pier is determined by taking the impact hinge risk value k as the judgment condition. The recommended layout of the three types of structures is as follows: Fig.10 shown.

[0069] The present invention provides a design method for a wide tail pier of a flood discharge gate. By establishing a single-hole mathematical model of the flood discharge gate, the law of hydraulic jump variation can be studied, and the calculation results of various design schemes can be quickly obtained. By further evaluating the calculation results, the optimal design scheme of the wide tail pier is determined by taking the impact support hinge risk value k as a judgment condition, and the optimal structural form of the wide tail pier can be determined quickly and accurately.

[0070] Example 2

[0071] A flood discharge gate is designed using the design method for a wide tail pier of a flood discharge gate as described in Example 1.

[0072] The flood discharge gate described in the present invention is designed using the design method described in Example 1. The wide tail pier of the flood discharge gate after design optimization can effectively reduce the risk of water splashes on the surface of the water tongue impacting the gate support hinge, thereby ensuring the safe operation of the hub flood discharge gate.

[0073] 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 design method for a wide tail pier of a flood discharge gate, characterized in that: The following steps are involved: S1: Establish a mathematical model of a single hole of the flood discharge gate; determine the structural design parameters of the wide tail pier, including the tail pier type, hole width before contraction, pier tail angle, contraction ratio, outlet width, contraction section length and pier top elevation; S2: Combining the structural design parameters to form multiple wide tail pier design schemes, and inputting each design scheme into the mathematical model for calculation to obtain the calculation results; S3: The optimal design scheme of the wide tail pier is determined by taking the impact hinge risk value k as the judgment condition, k = f (water jump head position, jump head water depth, maximum bottom flow velocity of the lock chamber, discharge flow, lock chamber water surface line), where f is a function.

2. The design method of a wide tail pier of a flood discharge gate according to claim 1 is characterized in that: In S3, the expression of the impact hinge risk value k is as follows: k = n1f1 (water jump head position) + n2f2 (jump head water depth) + n3f3 (maximum bottom flow velocity of the lock chamber) +n4f4(discharge flow)+n5f5(water surface line of lock chamber); In the formula, f1, f2, f3, f4, and f5 are functions respectively, n1, n2, n3, n4, and n5 are coefficients respectively, and n1+n2+n3+n4+n5=1.

3. The design method of a wide tail pier of a flood discharge gate according to claim 1 is characterized in that: In S3, n1≥n2>n3≥n4≥n5.

4. The design method of a wide tail pier of a flood discharge gate according to claim 1 is characterized in that: In S1, the model range of the single-hole mathematical model of the spillway is from l1m above the dam to l2m below the dam, where l2>l1.

5. The design method of a wide tail pier of a flood discharge gate according to claim 1, characterized in that: In S1, when establishing the mathematical model of a single hole of the flood discharge gate, the upstream boundary adopts the water level boundary, and the downstream boundary adopts the water level boundary.

6. The design method of a wide tail pier of a flood discharge gate according to claim 1, characterized in that: In S1, the tail pier types include rectangular, Y-shaped and X-shaped.

7. The design method of a wide tail pier of a flood discharge gate according to claim 1, characterized in that: In S1, the structural design parameters also include whether the bottom is hollow and the hollow height of the bottom.

8. A method for designing a wide tail pier of a flood discharge gate according to any one of claims 1 to 7, characterized in that: The numerical value of each of the structural design parameters is initially determined in a range based on theoretical calculations.

9. A design method for a wide tail pier of a flood discharge gate according to claim 8, characterized in that: The numerical value of each of the structural design parameters varies evenly.

10. A flood discharge gate, characterized in that: The design is obtained by adopting the design method of a wide tail pier of a flood discharge gate as described in any one of claims 1-9.

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