A deep-hole arrangement structure for flood discharge and energy dissipation of high arch dams

Abstract

This invention discloses a deep-hole arrangement structure for flood discharge and energy dissipation in a high arch dam, belonging to the field of water conservancy and hydropower technology. It includes a group of deep holes and a group of surface holes in the high arch dam. The group of deep holes comprises 5 to 7 flood discharge deep holes, arranged as follows: the outlet angle of the centrally located flood discharge deep hole is arranged in a downward angle, with an angle of -5 to -2°. The group of surface holes comprises 4 to 6 flood discharge surface holes, which are arranged alternately with the flood discharge deep holes. This invention effectively solves the problem of water jets from the downward angled deep holes impacting the inner side of the water cushion pond wall.

Description

Technical Field

[0001] This invention belongs to the field of water conservancy and hydropower engineering technology, and specifically discloses a new type of deep hole arrangement structure for flood discharge and energy dissipation of high arch dams. Background Technology

[0002] Arch dams typically utilize stratified outflow from surface (or shallow) orifices and central orifices, along with the collision of upper and lower water jets in the air to dissipate energy. This disperses the water jets longitudinally as much as possible, weakening the concentrated intensity of the jet. A stilling basin is constructed downstream to concentrate and dissipate the mechanical energy of the downstream flow. Engineering practice has shown that this is the most economical flood discharge and energy dissipation scheme, adopted in numerous projects both domestically and internationally, and has become a typical layout for high arch dam flood discharge and energy dissipation. Traditional deep-orifice arrangements generally employ symmetry with a projecting angle along the central axis and downward angles on both sides. The water droplet is located with the central deep orifice having the furthest projecting distance, while the two side orifices are closer to the dam toe, forming a V-shape with the opening facing the dam toe.

[0003] However, the existing deep hole arrangement for high arch dams has the following problems: the deep holes on both sides are of the downward angle type, the water jet entry angle is large, the water drop point is close to the dam site and the side wall of the water cushion pond, and the distance between the deep holes on both sides is limited, making it difficult for the water jets on both sides to converge towards the center. Therefore, the horizontal width requirement of the water cushion pond is large.

[0004] In view of this, the present invention provides a novel deep-hole arrangement for high arch dams to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a deep-hole arrangement structure for flood discharge and energy dissipation in high arch dams to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A deep-hole arrangement structure for flood discharge and energy dissipation of a high arch dam includes a group of deep-holes and a group of surface holes. The group of deep-holes includes 5 to 7 flood discharge deep holes, and the arrangement of the flood discharge deep holes is as follows: the outlet angle of the centrally located flood discharge deep hole adopts a downward angle type, and the angle of the outlet angle is -5 to 2°; the group of surface holes includes 4 to 6 flood discharge surface holes, and the flood discharge surface holes and flood discharge deep holes are arranged alternately.

[0008] Preferably, the outlet angles of the deep discharge hole and the surface discharge hole both increase sequentially from the middle to both sides, and the difference between adjacent outlet angles is ≥10°.

[0009] Preferably, the orifice distance between the middle deep discharge hole and the flood discharge surface hole is the shortest, and the orifice distance on both sides increases sequentially. The center-to-center distance between adjacent water droplet points of each flood discharge deep hole and flood discharge surface hole is ≥30m.

[0010] Preferably, the distance between the water drop point of the deep flood discharge hole and the surface flood discharge hole in the middle and the dam body is ≥150m.

[0011] Preferably, the angle of depression of the middle flood discharge orifice is larger, and the angle of depression of the flood discharge orifices on both sides decreases sequentially.

[0012] Compared with the prior art, the present invention provides a deep-hole arrangement structure for flood discharge and energy dissipation of high arch dams, which has the following beneficial effects:

[0013] (1) The distance between the two sides of the water jet is increased, the angle of entry into the water is reduced, and the drop point is farther away from the dam site and the side wall of the water cushion pond than the conventional arrangement. The impact pressure on the inner side of the side wall is reduced, the impact pressure on the two sides of the slope is reduced, and the safety and stability of the dam body and the water cushion pond are protected.

[0014] (2) At the same time, due to the centripetal effect of the water tongues on both sides, the lateral water drop range is narrowed and the distance between the water drop points on both sides is reduced; the longitudinal stretching of the water tongues can narrow the water cushion pond, improve the energy dissipation efficiency per unit water body, and reduce the cost of the water cushion pond.

[0015] (3) When the deep hole arrangement proposed in this invention is increased, the water entry angle of the middle deep hole is increased, which makes full use of the energy dissipation space in the middle of the water cushion pond, which is conducive to increasing the turbulence of the water flow in the middle, improving the energy dissipation efficiency, and reducing the flow velocity of the water flowing out of the pond.

[0016] (4) The water jet drop point of the surface hole in this invention is arranged in the middle of the V-shaped drop point. By utilizing the dynamic water effect of the deep hole water jet, the dynamic water load of the surface hole on the water cushion pond is reduced. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the deep hole arrangement structure proposed in Embodiment 1 of the present invention;

[0018] Figure 2 This is a schematic diagram of the water drop point in the traditional deep hole arrangement structure of Embodiment 1 of the present invention;

[0019] Figure 3 This is a schematic diagram of the water drop point of the novel deep hole arrangement structure proposed in Embodiment 1 of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1:

[0022] Taking a high dam project as an example, the water level difference between the upstream and downstream sides under normal water level is approximately 210m, and the elevation of the deep borehole arrangement is approximately 100m from the downstream water level. Two arrangement schemes were compared on a 1:50 scale model of the project: the common deep borehole arrangement with a large central angle and small side angles, and the novel deep borehole arrangement mentioned in this invention. The specific details are as follows:

[0023] Please see Figure 1-3 A deep-hole arrangement structure for flood discharge and energy dissipation of a high arch dam includes a group of deep holes and a group of surface holes. The group of deep holes contains 5 to 7 flood discharge deep holes, and the arrangement of the flood discharge deep holes is as follows: the outlet angle of the flood discharge deep hole in the central position adopts a downward angle type, and the angle of the outlet angle is -5 to 2°; the group of surface holes contains 4 to 6 flood discharge surface holes, and the flood discharge surface holes and flood discharge deep holes are arranged alternately.

[0024] The outlet angles of both the deep discharge orifice and the surface discharge orifice increase sequentially from the middle to both sides, with the difference between adjacent outlet angles being ≥10°.

[0025] The orifice spacing of the deep flood discharge hole and the surface flood discharge hole in the middle is the shortest, and the orifice spacing on both sides increases sequentially. The center-to-center distance between adjacent water droplet points of each deep flood discharge hole and the surface flood discharge hole is ≥30m.

[0026] The distance between the water drop points of the deep and surface spillway gates in the middle and the dam body is ≥150m.

[0027] The angle of depression of the middle spillway is larger, while the angles of depression of the two side spillway spillways decrease sequentially.

[0028] The deep-hole arrangement proposed in this invention increases the distance between the two sides of the jetting water tongues, reduces the water entry angle, and allows the water drop points to be farther from the dam site and the sidewalls of the stilling basin than in conventional arrangements. According to model test data from a certain project, the distance between the two sides of the deep-hole jetting water tongues increased from 58m in the conventional arrangement to 136m. This reduces the impact pressure on the inner sidewalls, decreasing the impact pressure on the side slopes from 3-5 × 9.8 kPa to 1.5 × 9.8 kPa, a reduction of 62.5%, thus protecting the safety and stability of the dam body and the stilling basin. Simultaneously, due to the centripetal effect of the two jetting water tongues, the lateral water drop range is narrowed, and the distance between the water drop points on both sides is reduced from 130m to 107m. The original deep-hole arrangement is 82% of the width of the cushion pond; the longitudinal stretching of the water tongue can narrow the cushion pond, improve the energy dissipation efficiency per unit water volume, and reduce the cost of the cushion pond; furthermore, the outlet flow velocity of the deep-hole arrangement structure proposed in this invention is 36m / s, and the inlet flow velocity is 56m / s. In the new deep-hole arrangement, the inlet angle of the middle deep hole is increased, making full use of the energy dissipation space in the middle of the cushion pond, which is conducive to increasing the turbulence of the water flow in the middle, improving the energy dissipation efficiency, and reducing the outflow velocity from 7-10m / s to 5-7m / s; the water tongue landing point of the surface hole can be arranged in the middle of the V-shaped landing point, utilizing the dynamic water effect of the deep-hole water tongue to reduce the dynamic water load of the surface hole on the cushion pond.

[0029] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concept, should be covered within the scope of protection of the present invention.

Claims

1. A high arch dam flood discharge and energy dissipation deep hole arrangement structure, characterized in that, The high arch dam deep hole group comprises 5-7 flood discharge deep holes, and the outlet angle of the central flood discharge deep hole is arranged in a downward angle type, and the angle of the outlet angle is-5-2°; the surface hole group comprises 4-6 flood discharge surface holes, and the flood discharge surface holes and the flood discharge deep holes are arranged alternately; The angle of the outlet angle of the flood discharge deep hole and the flood discharge surface hole is sequentially increased from the middle to both sides, and the difference value of adjacent outlet angles is greater than or equal to 10°; The hole port lead distance of the flood discharge deep hole and the flood discharge surface hole is closest in the middle, and the hole port lead distance is sequentially increased on both sides, and the center distance between adjacent water fall points of each flood discharge deep hole and flood discharge surface hole is greater than or equal to 30 m; The distance between the water fall point of the flood discharge deep hole and the flood discharge surface hole and the dam body is greater than or equal to 150 m in the middle; The downward angle of the flood discharge surface hole is larger in the middle, and the downward angle of the flood discharge surface hole is sequentially decreased on both sides.

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