Dam body for flood discharge of arch dam body

Abstract

The invention belongs to the technical field of water conservancy and hydropower engineering, and particularly relates to a dam body for flood discharge of an arch dam body. The dam body comprises a dam body. A flood discharge surface hole and a flood discharge middle hole are formed in the dam body; the number of the surface flood discharge holes is multiple, the multiple surface flood discharge holes are formed in the upper surface of the dam body at equal intervals in the width direction of the dam body, and the included angle between a bottom plate of the outlet section of each surface flood discharge hole and the horizontal plane ranges from 30 degrees to 35 degrees. The multiple flood discharge middle holes are formed in the middle of the dam body at equal intervals in the width direction of the dam body, and bottom plates of the flood discharge middle holes are parallel to the horizontal plane. Through cooperation of the flood discharge surface hole and the flood discharge middle hole in the dam body, collision-free energy dissipation in the air of the nappe can be achieved, the energy dissipation efficiency is improved, longitudinal diffusion in the air and special transverse diffusion can be guaranteed, impact on a downstream plunge pool is reduced, and the service life of the dam body is prolonged. And meanwhile, cavitation erosion damage caused by the fact that a nappe hits a mesopore hoist chamber and a mesopore flow channel can be avoided, and safe operation of a dam is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of water conservancy and hydropower engineering, and in particular relates to a dam body used for flood discharge of an arch dam. Background Art

[0002] In order to reduce the scouring of the downstream river channel by the discharged water during the operation of the dam, the engineering usually adopts the method of combining surface holes with middle holes to divert the flow and set up water cushion ponds downstream to discharge flood water and dissipate energy; among them,

[0003] The surface holes and the middle holes are arranged in double layers, and energy is dissipated by the collision of the water tongues of the surface holes and the middle holes in the air, thereby achieving the purpose of reducing the impact pressure and pulsating pressure of the water flow on the water cushion pond floor; this arrangement scheme has been adopted by many water conservancy projects at home and abroad due to its simple structure.

[0004] This traditional arrangement of surface holes and middle holes is widely used, but it often has some problems. For example, the lateral diffusion of the water tongue in the air is large, and the requirement for the width of the water cushion pond is also increased accordingly, thereby increasing the cost of the project.

[0005] Although some arrangements have been proposed to reduce lateral diffusion, they can only reduce the lateral diffusion of deep hole water tongues, and cannot comprehensively adjust the lateral diffusion of surface hole and deep hole water tongues. In some special terrain conditions, such as the gradual widening of the terrain from the outlet of some dam sites to the downstream river valley, it is possible that the water tongues of the surface holes will impact the slopes on both sides, and the requirements for the cushion pond will also increase.

[0006] At the same time, the span of the water tongue is generally small, which causes the water flow point to be closer to the dam site, and there is also a risk that the lower edge of the water tongue will hit the middle hole gate room.

[0007] In addition, the high-speed water flow in the middle hole flow channel easily produces a low-pressure area, which causes the formation and collapse of bubbles in the water, and then causes cavitation damage to the structure. Therefore, it is a technical problem that those skilled in the art need to solve urgently to invent a structure that can reduce the lateral diffusion of the surface hole and the middle hole water tongue to reduce its scouring of the water cushion pond and the bank slopes on both sides. Summary of the invention

[0008] The present invention provides a dam body for flood discharge of an arch dam, so as to solve the technical problem that the dam body structure in the prior art cannot comprehensively adjust the lateral diffusion of the surface holes and the deep hole water tongues, resulting in the water tongues of the surface holes impacting the slopes on both sides and increasing the requirements for the water cushion pond.

[0009] The present invention is achieved through the following technical solutions:

[0010] A dam body for flood discharge of an arch dam, comprising a dam body;

[0011] The dam body is provided with a surface discharge hole and a middle discharge hole; wherein,

[0012] The number of the flood discharge holes is multiple, and the multiple flood discharge holes are arranged on the upper surface of the dam body at equal intervals along the width direction of the dam body, and the angle between the bottom plate of the outlet section of the flood discharge hole and the horizontal plane is 30-35°;

[0013] There are multiple flood discharge holes, which are evenly spaced in the middle of the dam body along the width direction of the dam body, and the flood discharge holes are spaced apart from the flood discharge surface holes in the horizontal direction, and the bottom plates of the flood discharge holes are parallel to the horizontal plane.

[0014] In order to better realize the present invention, further optimization is made in the above structure, the number of the flood discharge surface holes is three, and the three flood discharge surface holes are respectively one middle surface hole and two side surface holes;

[0015] The slope of the bottom plate of the outlet section of the side surface hole is 1:1.4;

[0016] The slope of the bottom plate of the outlet section of the middle surface hole is 1:1.2.

[0017] In order to better realize the present invention, further optimization is made in the above structure, and the end of the flood discharge surface hole adopts the arrangement form of a Y-shaped wide tail pier.

[0018] In order to better realize the present invention, further optimization is made in the above structure, and the bottom plate of the flood discharge surface hole is hollowed out.

[0019] In order to better realize the present invention, further optimization is made in the above structure. The number of the flood discharge holes is four, the four flood discharge holes are arranged in a narrow slit as a whole, and the width of the water inlet of the flood discharge hole is greater than the width of the water outlet of the flood discharge hole.

[0020] In order to better realize the present invention, further optimization is made in the above structure, and the four flood discharge holes are two middle holes and two side holes respectively;

[0021] The width of the water inlet of the two side holes is equal to the width of the water inlet of the two middle holes, and the width of the water outlet of the two side holes is greater than the width of the water outlet of the two middle holes.

[0022] In order to better realize the present invention, further optimization is made in the above structure, and the inlet section of the flood discharge hole adopts a smooth transition curve.

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

[0024] The cooperation of the surface flood discharge holes and the middle flood discharge holes in the dam body for flood discharge of the arch dam provided by the present invention can realize the collision-free energy dissipation of the water tongue in the air, improve the energy dissipation efficiency, and can ensure the longitudinal diffusion in the air and a special lateral diffusion, reduce the impact on the downstream water cushion pond, and at the same time avoid the cavitation damage of the water tongue hitting the middle hole opening and closing machine room and the middle hole flow channel, thereby ensuring the safe operation of the dam. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a side cross-sectional view of a dam body used for flood discharge of an arch dam in the present invention when it is in a working state;

[0027] Figure 2 It is a schematic structural diagram of a flood discharge surface hole in a dam body used for flood discharge in an arch dam according to the present invention;

[0028] Figure 3 It is a top view of a flood discharge surface hole in a dam body used for flood discharge of an arch dam according to the present invention;

[0029] Figure 4 It is a schematic structural diagram of a flood discharge hole in a dam body used for flood discharge in an arch dam according to the present invention;

[0030] Figure 5 It is a top view of a flood discharge hole in a dam body used for flood discharge in an arch dam according to the present invention;

[0031] Figure 6 It is a schematic diagram of the water tongue impact range of the flood discharge surface hole and the flood discharge middle hole of the dam body used for flood discharge of the arch dam body of the present invention;

[0032] Figure 7 The present invention is a front view of a dam body used for flood discharge of an arch dam.

[0033] In the figure:

[0034] 1. Dam body; 11. Surface hole for flood discharge; 111. Side surface hole; 112. Middle surface hole; 113. Y-shaped wide tail pier; 12. Middle hole for flood discharge; 121. Side middle hole; 122. Middle middle hole; 123. Narrow gap. DETAILED DESCRIPTION

[0035] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0036] In the description of the present invention, it should be noted that, unless otherwise specified, the meaning of "plurality" is two or more; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0037] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] Example:

[0039] like Figures 1 to 7 As shown:

[0040] A dam body for flood discharge of an arch dam, comprising a dam body 1;

[0041] The dam body 1 is provided with a surface discharge hole 111 and a middle discharge hole 12, see Figure 7 ;in,

[0042] There are multiple flood discharge holes 111, which are arranged at equal intervals on the upper surface of the dam body 1 along the width direction of the dam body 1, and the angle between the bottom plate of the outlet section of the flood discharge hole 111 and the horizontal plane is 30-35°;

[0043] There are multiple flood discharge holes 12, which are evenly spaced in the middle of the dam body 1 along the width direction of the dam body 1, and the flood discharge holes 12 are spaced apart from the flood discharge surface holes 111 in the horizontal direction, and the bottom plate of the flood discharge holes 12 is parallel to the horizontal plane.

[0044] The cooperation between the surface flood discharge hole 111 and the middle flood discharge hole 12 in the dam body can realize the collision-free energy dissipation of the water tongue in the air, improve the energy dissipation efficiency, and ensure the longitudinal diffusion in the air and a special lateral diffusion, reduce the impact on the downstream water cushion pond, and at the same time avoid the cavitation damage of the water tongue hitting the middle hole opening and closing machine room and the middle hole flow channel, thereby ensuring the safe operation of the dam.

[0045] As a specific embodiment of the present invention, the number of the above-mentioned flood discharge surface holes 111 is three, and the three flood discharge surface holes 111 are respectively one middle surface hole 112 and two side surface holes 111; the number of the above-mentioned flood discharge middle holes 12 is four, and the four flood discharge middle holes 12 are respectively two middle middle holes 122 and two side middle holes 121; the three flood discharge surface holes 111 and the four flood discharge middle holes 12 are arranged alternately in sequence, that is, from one side to the other side of the dam body 1, the arrangement order of the three flood discharge surface holes 111 and the four flood discharge middle holes 12 is: side middle hole 121, side surface hole 111, middle middle hole 122, middle surface hole 112, middle middle hole 122, side surface hole 111 and side middle hole 121, see Figure 7 ;

[0046] The slope of the bottom plate of the outlet section of the above-mentioned side surface hole 111 is 1:1.4;

[0047] The slope of the bottom plate of the outlet section of the middle surface hole 112 is 1:1.2, see Figure 2 .

[0048] The four flood discharge holes 12 are arranged as a whole with narrow slits 123, and the width of the water inlet of the flood discharge hole 12 is greater than the width of the water outlet of the flood discharge hole 12. Figure 5 , to ensure that the water flows close to the hole wall to avoid cavitation.

[0049] The width of the water inlet of the two side holes 121 is equal to the width of the water inlet of the two middle holes 122 , and the width of the water outlet of the two side holes 121 is greater than the width of the water outlet of the two middle holes 122 .

[0050] Optimally, the end of the above-mentioned flood discharge surface hole 111 adopts the arrangement form of a Y-shaped wide tail pier 113, see Figure 3 .

[0051] Optimally, the bottom plate of the above-mentioned flood discharge surface hole 111 is hollowed out.

[0052] Optimally, the inlet section of the above-mentioned flood discharge hole 12 adopts a smooth transition curve, see Figure 4 , to improve inflow conditions.

[0053] In order to better illustrate the practical effect of the dam body used for arch dam body flood discharge, this embodiment takes a certain high arch dam project as an example to specifically explain the structure and effect of the dam body used for arch dam body flood discharge, as follows:

[0054] This scheme adopts three surface discharge holes 111 and four middle discharge holes 12 arranged symmetrically. Figure 7 , that is, the three surface flood discharge holes 111 and the four middle flood discharge holes 12 are arranged alternately in sequence; wherein,

[0055] The bottom plates of the outlet sections of the two side surface holes 111 adopt a depression angle of 35°, and the bottom plate of the outlet section of the middle surface hole 112 adopts a depression angle of 40°, and the bottom plates of the outlet sections of the two side surface holes 111 maintain a slope of 1:1.4 until the end, and the bottom plate of the outlet section of the middle surface hole 112 maintains a slope of 1:1.2 until the end;

[0056] The above-mentioned flood discharge holes 12 are arranged in the middle part of the dam body 1, the inlet size of the four flood discharge holes 12 is 5m×13m, and the outlet size of the four flood discharge holes 12 is 5m×7m; the bottom plates of the four flood discharge holes 12 are all horizontally arranged, that is, the bottom plates of the flood discharge holes 12 are parallel to the horizontal plane.

[0057] On the basis of the above design scheme, further optimized design is carried out. For the three flood discharge holes 111, the outlet section of the flood discharge hole 111 adopts the arrangement form of Y-shaped wide tail pier 113 (horizontal length 12m, height 18m), the contraction ratio is 0.52, the side wall 10m straight pier above adopts a triangular wedge body, the tail height is 8m, the height of the wide tail pier 113 at the beginning is 5m, the bottom plate of the flood discharge hole 111 is 4m hollow, and the flood discharge hole 111 weir top elevation is 2521m;

[0058] The overall shape of the flood discharge hole 12 is arranged with a narrow slit 123, the flow width of the two side holes 121 is narrowed from 5m to 4m, and the flow width of the two middle holes 122 is narrowed from 5m to 3m.

[0059] In order to prevent the water tongue of the flood discharge hole 12 from directly hitting the working gate pier, the narrow slit 123 arranged 5.6m behind the outlet bottom plate of the four flood discharge holes 12 is moved 1.4m to the downstream side of the dam body as a whole. The distance between the narrow slit 123 and the outlet bottom plate of the flood discharge hole 12 is 7m.

[0060] The center line of the flood discharge surface hole 111 and the flood discharge middle hole 12 coincides with the center line of the water cushion pond;

[0061] The inlet section of the flood discharge hole 12 adopts a smooth transition curve to improve the inflow conditions;

[0062] The outlet section of the flood discharge hole 12 is arranged with a gradually narrowing narrow slit 123 to ensure that the water flows closely to the hole wall to avoid cavitation.

[0063] The surface pore shape proposed in the present invention can achieve the following effects:

[0064] 1. Under various typical working conditions, the top water crown caused by the shock wave at the upper edge of the water tongue of the flood discharge surface hole 111 has good stability, and occasionally collides with the spalling edge of the water tongue of the flood discharge middle hole 12, basically achieving non-collision of the water tongue.

[0065] 2. The water tongue of the flood discharge surface hole 111 falls closer to the dam site, its lateral diffusion is more stable, and the impact range is roughly rectangular, and will not impact the side walls of the water cushion pond; the water tongue of the flood discharge middle hole 12 falls away from the dam site, and its lateral diffusion gradually decreases from near to far, and the impact range is roughly trapezoidal, see Figure 6 It will not impact the side walls of the cushion pond, which is beneficial to ensuring the stability of the downstream slope.

[0066] 3. Under the conditions of verification, design, and energy dissipation and anti-scouring, the maximum time-averaged pressure values ​​of the water cushion pond bottom plate were 47.44×9.8kPa, 46.32×9.8kPa, and 47.12×9.8kPa, respectively, and the maximum impact pressure values ​​were 5.68×9.8kPa, 5.72×9.8kPa, and 4.8×9.8kPa, respectively. Compared with the classic design, the water tongue of the arch dam body used for flood discharge has a larger longitudinal diffusion in the air, which reduces the impact pressure of the water body when entering the water, improves the energy dissipation efficiency, and reduces the impact on the water cushion pond, thereby saving the corresponding engineering protection and having certain economic benefits.

[0067] 4. The bottom plate was hollowed out 4m before the outlet of the flood discharge surface hole 111, and the water tongue fell in advance. The lower edge of the water tongue of the flood discharge surface hole 111 was located on the downstream side of the hoisting and shutting machine room, and the minimum spacing distance was 4.6m. After the narrow slit 123 of the flood discharge middle hole 12 was translated to the downstream side to 7m of the outlet bottom plate, the water tongue would not impact the middle hole working gate support pier, and the measured water surface line was about 0.6~0.8m lower than the gate support hinge support pier.

[0068] 5. The average flow velocity in the cross section of the flow channel from the flood discharge hole 12 to the narrow slit 123 is less than the critical flow velocity for cavitation, which can avoid cavitation damage. The water flow condition in the flow channel of the flood discharge hole 12 is good, and the water flows closely to the wall surface, avoiding cavitation damage caused by water flow separation, which is conducive to ensuring the safe operation of the dam.

[0069] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A dam body for flood discharge of an arch dam, characterized in that: It comprises a dam body (1); The dam body (1) is provided with a surface flood discharge hole (11) and a middle flood discharge hole (12); wherein: The number of the flood discharge holes (11) is multiple, and the multiple flood discharge holes (11) are arranged at equal intervals on the upper surface of the dam body (1) along the width direction of the dam body (1), and the angle between the bottom plate of the outlet section of the flood discharge holes (11) and the horizontal plane is 30-35°; The number of the flood discharge middle holes (12) is multiple, and the multiple flood discharge middle holes (12) are arranged at equal intervals in the middle part of the dam body (1) along the width direction of the dam body (1), and the flood discharge middle holes (12) and the flood discharge surface holes (11) are arranged at intervals in the horizontal direction, and the bottom plates of the flood discharge middle holes (12) are parallel to the horizontal plane.

2. The dam body for flood discharge of an arch dam according to claim 1, characterized in that: The number of the flood discharge surface holes (11) is three, and the three flood discharge surface holes (11) are respectively a middle surface hole (112) and two side surface holes (111); The slope of the bottom plate of the outlet section of the side surface hole (111) is 1:1.4; The slope of the bottom plate of the outlet section of the middle surface hole (112) is 1:1.

2.

3. The dam body for flood discharge of an arch dam according to claim 2, characterized in that: The end of the flood discharge surface hole (11) is arranged in the form of a Y-shaped wide tail pier (113).

4. The dam body for flood discharge of an arch dam according to claim 3, characterized in that: The bottom plate of the flood discharge surface hole (11) is hollowed out.

5. The dam body for flood discharge of an arch dam according to any one of claims 1 to 4, characterized in that: The number of the flood discharge holes (12) is four, the four flood discharge holes (12) are arranged as a whole in a narrow slit (123), and the width of the water inlet of the flood discharge hole (12) is greater than the width of the water outlet of the flood discharge hole (12).

6. The dam body for flood discharge of an arch dam according to claim 5, characterized in that: The four flood discharge holes (12) are respectively two middle holes (122) and two side holes (121); the width of the water outlets of the two side holes (121) is greater than the width of the water outlets of the two middle holes (122).

7. The dam body for flood discharge of an arch dam according to claim 1, characterized in that: The inlet section of the flood discharge hole (12) adopts a smooth transition curve.

Images