Sediment retention and water diversion system for the headworks of hydropower stations

Abstract

The present invention belongs to the technical field of water conservancy and hydropower engineering, and specifically is a sand-trapping and water-bending system for the head hub of a hydropower station with good sand-flushing effect and low cost. The sand-trapping and water-bending system can form an effective water diversion and sand-prevention facility with a sand-trapping dam, a water intake, and a sand-flushing gate by setting a mesh-screen slag retaining wall. It is suitable for use in the head hub of a hydropower station for water diversion and sand prevention, and is particularly suitable for use in sediment rivers with steep gradients. Since the sand-trapping and water-bending system can effectively block large-particle bedloads by setting a mesh-screen slag retaining wall, and can effectively prevent sediment from entering the water intake together with the sand-trapping dam, it ensures that the water intake is "clear" and has a good sand-flushing effect. Therefore, there is no need to arrange a slag retaining dam at the tail of the reservoir upstream of the head hub of the hydropower station, which makes the project layout simple, the construction convenient, the cost low, and can save construction time and investment.

Description

Technical Field

[0001] The invention belongs to the technical field of water conservancy and hydropower engineering, and particularly relates to a sand-trapping and water-binding system for a headworks hub of a hydropower station. Background Art

[0002] For rivers with steep gradients, high sediment content, and abundant solid runoff, the problem of water diversion and sand control at the headwater hub of a hydropower station is very prominent. Generally, the water intake is arranged on the concave bank of the river channel, and the sand flushing gate is arranged in the deep trough of the river channel, forming a "lateral water diversion and forward sand flushing" layout.

[0003] The dam of a hydropower station is one of the main facilities of a hydropower station. Figure 1 As shown, the dam of a hydropower station generally includes a water retaining dam section 210 set on the convex bank and the concave bank of the river, and also includes an overflow dam 220, a sand flushing gate 230 and a water intake 240 set in sequence along the cross-river direction between the water retaining dam sections 210. The sand interception and water confinement system is a facility used to address the water diversion and sand control problems of the headwater hub of a hydropower station; Figure 1 As shown, the existing sand-retaining and water-containment system includes a water-containment wall 330 and a sand-blocking bank 310; the water-containment wall 330 is arranged in the upstream reservoir 100 perpendicular to the dam axis, and its downstream end is connected to the area between the overflow dam 220 and the sand-flushing gate 230, and separates the water flow of the overflow dam 220 from the water flow of the sand-flushing gate 230; the sand-containment bank 310 is arranged in front of the water intake 240, and is located in the area between the water-containment wall 330 and the concave bank of the river channel, and is used to prevent upstream silt from entering the water intake 240; the narrow opening formed between the downstream end of the sand-containment bank 310 and the water-containment wall 330 corresponds to the inlet of the sand-flushing gate 230.

[0004] Since the existing sediment-retaining and water-binding system has the water-binding wall 330 arranged perpendicular to the dam axis, it is inevitable that some of the bedload sediment will be "transported" to the front of the sediment-retaining bank 310; especially for rivers with narrow valleys, rich sediment and solid runoff, the diameter of the solid runoff source may be several meters. Such a large-scale solid runoff source will clog the water intake 240 before reaching the water intake 240, and even worse, damage the water-binding wall 330 and the sediment-retaining bank 310; therefore, in order to ensure the sand-flushing effect of the hydropower station's head hub, the existing sediment-retaining and water-binding system also needs to arrange a slag retaining dam 340 at the tail of the reservoir upstream of the hydropower station's head hub to prevent large-particle bedload from approaching the head hub.

[0005] However, because the existing sand-trapping and water-diverting system requires not only the installation of a water-diverting wall 330 and a sand-trapping bank 310 in front of the dam, but also the arrangement of a slag retaining dam 340 at the tail of the reservoir upstream of the head hub, the engineering layout and construction diversion of the sand-trapping and water-diverting system are complicated, the construction is difficult, and the cost is too high. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a sand-trapping and water-binding system for the headworks of a hydropower station with good sand-flushing effect and low cost.

[0007] The technical solution adopted by the present invention to solve its technical problems is: a sand-trapping and water-binding system for the headworks hub of a hydropower station, including a sand-trapping bank arranged upstream of the water intake, and also including a mesh-type slag retaining wall. The mesh-type slag retaining wall is arranged in the upstream reservoir, and its downstream end is connected to the area between the sand flushing gate and the overflow dam, and the angle θ between its axis and the axis of the sand flushing gate is 60°~80°.

[0008] The mesh-type slag retaining wall is provided with sand discharge holes, which are inclined holes, and the hole ends close to the sand retaining embankment are higher than the hole ends away from the sand retaining embankment.

[0009] There are at least two rows of sand discharge holes, each row includes at least two sand discharge holes spaced apart along the axial direction of the mesh screen type slag retaining wall, and the sand discharge holes in any two adjacent rows are staggered.

[0010] Furthermore, the bottom plate of the water intake is more than 5.5m higher than the bottom plate of the sand flushing gate, and the top of the sand barrier is more than 0.5m higher than the bottom plate of the water intake.

[0011] Furthermore, the top of the mesh-screen slag retaining wall is more than 2.5m higher than the top of the sand barrier, and the top of the mesh-screen slag retaining wall is more than 1m higher than the normal water level of the upstream reservoir.

[0012] Furthermore, the mesh screen type slag retaining wall includes a bottom plate, a wall body arranged on the bottom plate, and a top beam arranged on the top of the wall body, and the sand discharge holes are arranged on the wall body.

[0013] Furthermore, the cross section of the wall body is a trapezoidal surface that is narrow at the top and wide at the bottom.

[0014] Furthermore, the side surface of the wall body close to the sand barrier is a vertical surface, and the side surface away from the sand barrier is an inclined surface.

[0015] Furthermore, the inclination gradient of the sand discharge hole is 15%.

[0016] Furthermore, the cross section of the sand discharge hole is rectangular.

[0017] The beneficial effects of the present invention are as follows: the sand-trapping and water-binding system can form an effective water diversion and sand-prevention facility with the sand-trapping bank, water intake and sand flushing gate through the mesh screen slag retaining wall, and is suitable for use in the head hub of a hydropower station for water diversion and sand prevention, and is particularly suitable for use in sediment rivers with steep gradients; by making the angle θ between the axis of the mesh screen slag retaining wall and the axis of the sand flushing gate 60° to 80°, most of the bedload sediment can be blocked in front of the sand-trapping bank; at the same time, at least two rows of staggered sand discharge holes are provided on the mesh screen slag retaining wall, and since the sand discharge holes are inclined holes with the hole ends close to the sand-trapping bank higher than the hole ends away from the sand-trapping bank, On the one hand, it can allow water to flow through the mesh-type slag retaining wall to supply water to the water intake. On the other hand, it can ensure that when water flows through the sand discharge hole, most of the sediment it carries flows back along the inclined direction of the sand discharge hole, and only a small part of the sediment flows to the front of the sand retaining bank. In addition, since the sand retaining and water-bearing system can effectively block large-particle bedload by setting up a mesh-type slag retaining wall, and can effectively prevent sediment from entering the water intake together with the sand retaining bank, ensuring that the water intake is "clear" and the sand flushing effect is good. Therefore, there is no need to arrange a slag retaining dam at the tail of the reservoir upstream of the head hub of the hydropower station, which makes the project layout simple, the construction convenient, the cost low, and can save construction time and investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a plan layout of the existing sediment retention and water diversion system at the head hub of the hydropower station.

[0019] Figure 2 It is a plan layout diagram of the present invention.

[0020] Figure 3 It is along Figure 2 Sectional view along line AA.

[0021] Figure 4 It is along Figure 2 Cross-sectional view along line BB.

[0022] In the figure, the following are marked: upstream reservoir 100, normal water level 110, water retaining dam section 210, overflow dam 220, sand flushing gate 230, water intake 240, sand barrier 310, mesh slag retaining wall 320, sand discharge hole 321, bottom plate 322, wall body 323, top beam 324, water restraining wall 330, slag retaining dam 340; Figure 1 and Figure 2 The direction of the arrow in the middle indicates the direction of water flow. DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to the accompanying drawings.

[0024] In the description of the present invention, it should be understood that the terms "upstream", "downstream", "top", "bottom", "inside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the mechanism or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0025] Combine Figure 2 、 Figure 3 and Figure 4 As shown, the sand-trapping and water-binding system for the headwater hub of a hydropower station includes a sand-trapping bank 310 arranged upstream of the water intake 240, and also includes a mesh-type slag retaining wall 320. The mesh-type slag retaining wall 320 is arranged in the upstream reservoir 100, and its downstream end is connected to the portion between the sand flushing gate 230 and the overflow dam 220, and the angle θ between its axis and the axis of the sand flushing gate 230 is 60° to 80°.

[0026] The mesh-type slag retaining wall 320 is provided with sand discharge holes 321. The sand discharge holes 321 are inclined holes, and the hole ends close to the sand retaining bank 310 are higher than the hole ends away from the sand retaining bank 310. The inclination gradient of the sand discharge holes 321 is generally determined according to factors such as the sediment content of the river and the number of sand discharge holes 321. Preferably, the inclination gradient of the sand discharge holes 321 is 15%. The cross-section of the sand discharge holes 321 can be of various shapes and structures, such as: circular, elliptical, polygonal, etc., preferably rectangular, which is convenient for construction and can ensure that the sand discharge holes 321 have a good water and sand discharge effect.

[0027] The sand discharge holes 321 are arranged in at least two rows, each row including at least two sand discharge holes 321 spaced apart along the axial direction of the mesh slag retaining wall 320, and the sand discharge holes 321 in any two adjacent rows are staggered. Figure 4 In the embodiment, three rows of sand discharge holes 321 are provided.

[0028] The sand intercepting and water guiding system is realized by setting up a mesh type slag retaining wall 320, and making the angle θ between the axis of the mesh type slag retaining wall 320 and the axis of the sand flushing gate 230 be 60°~80°, and at the same time, at least two rows of staggered sand discharge holes 321 are set on the mesh type slag retaining wall 320, and since the sand discharge holes 321 are inclined holes with the hole ends close to the sand retaining bank 310 higher than the hole ends away from the sand retaining bank 310, most of the upstream large-grained bedload and river water flow can be diverted to the front of the overflow dam 220, and only the fine-grained bedload and water flow can be discharged into the sedimentation trough formed by the mesh type slag retaining wall 320, the water intake 240 and the sand retaining bank 310 through the sand discharge holes 321, forming water binding and sand attack. When passing through the sand discharge hole 321, most of the carried sediment flows back along the inclined direction of the sand discharge hole 321, and only a small part of the sediment flows in front of the sand retaining bank 310. The particle size of this part of the sediment is relatively small, so it can achieve a good sand flushing effect, effectively preventing sediment from entering the water intake 240, ensuring that the water intake 240 is "clear in front of the gate", reducing the wear and tear of the turbine caused by sediment passing through the machine, and no longer needing to arrange a slag retaining dam 340 at the tail of the reservoir upstream of the head hub of the hydropower station, thereby making the project layout simple, construction convenient, cost-effective, saving construction time, and saving investment; it can be seen that the sand retaining and water-bundling system is suitable for use in the head hub of a hydropower station for water diversion and sand prevention, and is particularly suitable for use in sediment rivers with steep gradients and many sediments.

[0029] Specifically, the bottom plate of the water intake 240 is more than 5.5m higher than the bottom plate of the sand flushing gate 230, and the top of the sand retaining dam 310 is more than 0.5m higher than the bottom plate of the water intake 240; in this way, good water intake and sand retaining effects can be ensured, and the bed load sediment before reaching the water intake 240 can be effectively intercepted.

[0030] On the basis of the above, in order to ensure that the mesh-type slag retaining wall 320 achieves the best effect of blocking large-particle transported sediment, it is preferred that the top of the mesh-type slag retaining wall 320 is more than 2.5m higher than the top of the sand barrier 310, and the top of the mesh-type slag retaining wall 320 is more than 1m higher than the normal water level 110 of the upstream reservoir 100.

[0031] In order to improve the slag retaining effect of the mesh slag retaining wall 320 and ensure its structural strength, Figure 3 As shown, the mesh-type slag retaining wall 320 includes a bottom plate 322, a wall body 323 disposed on the bottom plate 322, and a top beam 324 disposed at the top of the wall body 323. The sand discharge holes 321 are disposed on the wall body 323. The bottom plate 322 is the base of the mesh-type slag retaining wall 320, the wall body 323 is the main body of the mesh-type slag retaining wall 320, and the top beam 324 is the top portion of the mesh-type slag retaining wall 320. The bottom plate 322, the wall body 323, and the top beam 324 are typically cast as one piece.

[0032] In order to further improve the overall structural strength of the mesh slag retaining wall 320, Figure 3 As shown, it is preferred that the cross section of the wall body 323 is a trapezoidal surface that is narrow at the top and wide at the bottom.

[0033] Specifically, the side of the wall body 323 close to the sand retaining bank 310 is a vertical surface, and the side away from the sand retaining bank 310 is an inclined surface; in this way, it can be ensured that the side of the wall body 323 away from the sand retaining bank 310 has good slag blocking and diversion effects, so as to smoothly guide most of the upstream large-particle bed load and river water to the front of the overflow dam 220.

[0034] Specifically, the spacing between the sand drainage holes 321 is 1.2 meters, with the spacing between the sand drainage holes 321 in each row being 1.8 meters. Furthermore, the distance between the sand drainage holes 321 in the bottom row and the bottom plate 322 is 0.5 meters. This ensures that the mesh slag retaining wall 320 has optimal water and sand removal performance. The sand drainage holes 321 are preferably square with a cross-sectional dimension of 0.8 meters by 0.8 meters.

Claims

1. A sediment interception and water confinement system for a hydropower station headwater hub, comprising a sediment interception bank (310) arranged upstream of a water intake (240), wherein the bottom plate of the water intake (240) is higher than the bottom plate of a sand flushing gate (230) by more than 5.5 m, and the top of the sediment interception bank (310) is higher than the bottom plate of the water intake (240) by more than 0.5 m, and characterized in that: The invention also includes a mesh-type slag retaining wall (320), wherein the top of the mesh-type slag retaining wall (320) is higher than the top of the sand barrier (310) by more than 2.5 m, and the top of the mesh-type slag retaining wall (320) is higher than the normal water level (110) of the upstream reservoir (100) by more than 1 m. The mesh-type slag retaining wall (320) is arranged in the upstream reservoir (100), and its downstream end is connected to the portion between the sand flushing gate (230) and the overflow dam (220), and the angle θ between the axis of the mesh-type slag retaining wall (320) and the axis of the sand flushing gate (230) is 60° to 80°. The mesh-type slag retaining wall (320) is provided with sand discharge holes (321), the sand discharge holes (321) are inclined holes, and the hole ends close to the sand retaining embankment (310) are higher than the hole ends away from the sand retaining embankment (310); the sand discharge holes (321) are arranged in at least two rows, each row including at least two sand discharge holes (321) spaced apart along the axial direction of the mesh-type slag retaining wall (320), and the sand discharge holes (321) in any two adjacent rows are staggered; The mesh-type slag retaining wall (320) comprises a bottom plate (322), a wall body (323) arranged on the bottom plate (322), and a top beam (324) arranged at the top of the wall body (323); the sand discharge hole (321) is arranged on the wall body (323); the cross section of the wall body (323) is a trapezoidal surface that is narrow at the top and wide at the bottom; the side of the wall body (323) close to the sand retaining bank (310) is a vertical surface, and the side away from the sand retaining bank (310) is an inclined surface; the sand discharge hole (321) is arranged on the wall body (323); the inclination gradient of the sand discharge hole (321) is 15%, and the cross section of the sand discharge hole (321) is rectangular.

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