A multi-sediment bed load river channel water intake structure

Abstract

The present application relates to the technical fields of water conservancy and hydropower engineering, and discloses a multi-sediment bed load river channel water intake structure, which comprises a stable bed structure, a flow guide structure and a water intake structure, the stable bed structure is arranged perpendicularly to the water flow direction of the river channel, and one end of the stable bed structure is connected with one side of the river channel; one side of the flow guide structure is connected with the other end of the stable bed structure, and the other side is connected with one end of a flood discharge gate; the water intake structure comprises a water intake weir, a pre-sedimentation tank and a sand blocking ridge, the pre-sedimentation tank is arranged on the other side of the river channel, the outer wall of the pre-sedimentation tank is connected with the flood discharge gate, the water intake weir is arranged on the side of the pre-sedimentation tank close to the flood discharge gate, and the sand blocking ridge is arranged downstream of the pre-sedimentation tank, the present application stabilizes the river regime through the stable bed structure, narrows the river bed below the flow guide structure to discharge the bed load, and the water intake structure is used for water intake and sand setting, so that the problem of water diversion and sand prevention of the river channel water intake is solved, and the operation efficiency of the water intake system is improved.

Description

Technical Field

[0001] This invention relates to the field of water conservancy and hydropower engineering technology, specifically to a water intake structure for a multi-sediment bedload river channel. Background Technology

[0002] Mountain rivers are typically characterized by steep longitudinal slopes, high flow velocities, rapid and short-duration flood peaks, and frequent riverbed erosion and bank instability, leading to geomorphological changes. During the rainy season and floods, the water flow carries large amounts of large-diameter bedload and fine-particle suspended sediment downstream. For run-of-river hydropower stations that rely on natural river channels for water intake, the water diversion system is directly exposed to this high-sediment-content, high-transportation hydraulic environment. The water flow conditions at the hydropower station's intake are complex, with high sediment content and a wide particle size distribution, making siltation of the waterway and erosion of the water diversion components particularly prominent.

[0003] In current engineering practice, dams are typically installed near the intake of hydropower stations to alter local hydraulic conditions, optimizing the intake's location and elevation to reduce sediment load and alleviate siltation. Settlement ponds are then constructed after the intake. However, on the one hand, during peak flood periods, the combined effects of high sediment transport and rapid riverbed deformation can cause large-diameter bedloads to enter the intake, damaging it. Furthermore, these large-diameter bedloads tend to accumulate in front of the intake, affecting normal water intake. On the other hand, fine suspended sediment cannot settle sufficiently in the settling ponds after the intake in a short time, still carrying sediment into the hydropower station's water diversion system and accumulating in the diversion channels and equipment. This induces wear and secondary siltation in the diversion equipment, impacting the hydropower station's operational efficiency. Summary of the Invention

[0004] This invention provides a water intake structure for river channels with high sediment loads to solve the problem of water diversion and sand control in hydropower stations on rivers with high sediment loads.

[0005] In a first aspect, the present invention provides a water intake structure for multi-sediment bedload river channels, comprising:

[0006] A bed stabilization structure is provided perpendicular to the direction of water flow in the river channel, and one end of the bed stabilization structure is connected to one side of the river channel.

[0007] A flow-diverting structure is arranged along the direction of water flow in the river channel, and one side of the flow-diverting structure is connected to the other end of the bed-stabilizing structure;

[0008] The water intake structure includes a floodgate and an intake assembly. One end of the floodgate is connected to the other side of the diversion structure. The intake assembly includes an intake weir, a pre-sedimentation tank, and a sand-blocking sill. The pre-sedimentation tank is located on the other side of the river channel. The other end of the floodgate is connected to the outer wall of the pre-sedimentation tank. The intake weir is located on the side of the pre-sedimentation tank closest to the floodgate and is located upstream of the river channel. The sand-blocking sill is located downstream of the pre-sedimentation tank.

[0009] Beneficial effects

[0010] The bed stabilization structures are arranged laterally and fixedly connected to the shoreline, forming a stable riverbed benchmark in the vicinity of the intake and preventing flood erosion of the riverbed. The diversion structures are arranged in the direction of water flow and connected to the bed stabilization structures, guiding the main stream carrying larger-diameter bedloads towards the spillway. Flow direction control ensures the main stream avoids the intake area, allowing larger-diameter bedloads to be discharged through the spillway, reducing the amount of bedload entering the intake structures. The intake weir is located on one side of the spillway, allowing for sufficient settling of fine suspended particles in the pre-sedimentation tank, achieving water-sediment separation. A sand-blocking embankment is located downstream of the intake weir, blocking fine suspended particles and some sediment deposited at the bottom of the pre-sedimentation tank, further preventing them from entering the hydropower station's intake, maintaining sediment stability in the pre-sedimentation tank, and preventing wear on the hydropower station's generating units, thus extending their service life.

[0011] In one optional embodiment, the sand-blocking embankment is arranged perpendicular to the water flow direction of the river channel, and its two ends are respectively connected to the inner walls of the two sides of the pre-sedimentation tank.

[0012] In one alternative embodiment, the intake weir is set at an angle to the direction of water flow in the river channel.

[0013] Beneficial effects

[0014] The intake weir is arranged at a predetermined angle relative to the direction of river flow. The water flows laterally into the pre-sedimentation tank, forming a swirling or spiral flow in the tank. This reduces the frontal impact force of the water entering the tank, making the flow pattern distribution in the tank more uniform and improving the water entry characteristics.

[0015] In one alternative embodiment, the top elevation of the sand-blocking embankment is higher than the bottom elevation of the pre-sedimentation tank, but lower than the top elevation of the water intake weir.

[0016] In one alternative embodiment, the top of the pre-settling tank sidewall gradually slopes inward to the bottom of the pre-settling tank sidewall and connects to the bottom surface of the pre-settling tank.

[0017] Beneficial effects

[0018] The reduced lateral width of the water flow at the bottom of the pre-sedimentation tank lowers the local flow velocity, which is beneficial for the settling and concentration of suspended fine particles. The inward-sloping sidewalls of the pre-sedimentation tank also guide the deposited silt to slide naturally along the slope and converge to the center of the tank bottom, preventing silt from accumulating at the corners of the tank walls and creating dead zones, thus reducing blind spots in dredging.

[0019] In one optional embodiment, a sand flushing channel is provided on the bottom surface of the pre-sedimentation tank, and the sand discharge end of the sand flushing channel passes through the sand retaining sill and is connected to the side wall of the downstream of the river channel.

[0020] Beneficial effects

[0021] The flushing channel can directionally collect and systematically discharge the silt accumulated in front of the sand-retaining embankment, avoiding disturbance to the water intake of the hydropower station units. At the same time, it reduces the secondary suspension and back-mixing of already deposited particles in the sedimentation tank, shortening the water body dredging shutdown time.

[0022] In one alternative embodiment, the diversion structure includes a diversion wall arranged along the direction of the river flow, the end of the diversion wall near the upstream of the river inclined along the side away from the floodgate.

[0023] Beneficial effects

[0024] The upstream end of the guide wall is inclined away from the floodgate, which can effectively divert and guide the river flow. It deflects the high-energy mainstream carrying a large amount of bedload to the floodgate side. The bedload is driven by the water flow and flows into the downstream of the river through the floodgate, reducing the bedload at the source and entering the pre-sedimentation tank.

[0025] In one alternative implementation, the bottom elevation of the spillway gate is lower than the top elevation of the intake weir.

[0026] In one alternative implementation, the bottom elevation of the floodgate is lower than the elevation of the river channel, and the slope of the floodgate is greater than the average slope of the river channel bottom.

[0027] In one alternative embodiment, the bed stabilization structure includes a submerged dam, which is buried in the riverbed and has its top elevation at the same level as the river channel. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1This is a top view of a multi-sediment bedload river water intake structure according to an embodiment of the present invention;

[0030] Figure 2 This is a cross-sectional view of a multi-sediment bedload river water intake structure according to an embodiment of the present invention;

[0031] Figure 3 This is a side sectional view of the pre-sedimentation tank according to an embodiment of the present invention.

[0032] Explanation of reference numerals in the attached figures:

[0033] 11. Submerged dam;

[0034] 2. River channel;

[0035] 31. Deflector wall;

[0036] 41. Floodgate, 421. Intake weir, 422. Pre-sedimentation basin, 423. Sand-blocking embankment, 424. Sand-flushing channel. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0038] The following is combined with Figures 1 to 3 The following describes embodiments of the present invention.

[0039] According to an embodiment of the present invention, in one aspect, a water intake structure for a multi-sediment bedload river channel is provided, comprising: a bed stabilization structure, a flow guiding structure, and a water intake structure. The bed stabilization structure is arranged perpendicular to the water flow direction of the river channel 2, and one end of the bed stabilization structure is connected to one side of the river channel 2; the flow guiding structure is arranged along the water flow direction of the river channel 2, and one side of the flow guiding structure is connected to the other end of the bed stabilization structure; the water intake structure includes: a flood discharge gate 41 and a water intake assembly. One end of the floodgate 41 is connected to the other side of the diversion structure. The water intake components include: a water intake weir 421, a pre-sedimentation tank 422, and a sand retaining wall 423. The pre-sedimentation tank 422 is located on the other side of the river channel 2. The other end of the floodgate 41 is connected to the outer wall of the pre-sedimentation tank 422. The water intake weir 421 is provided on the side of the pre-sedimentation tank 422 near the floodgate 41, and the water intake weir 421 is located upstream of the river channel 2. A sand retaining wall 423 is provided downstream of the pre-sedimentation tank 422.

[0040] The bed stabilization structure uses a transverse base formed by integral casting of reinforced concrete. One end of the base is connected to the bank revetment of river channel 2 via anchor bars, providing a stable riverbed and bank constraint for the water intake structure. At the other end of the bed stabilization structure, a flow guide structure is set in the direction of water flow. The flow guide structure is a linear structural unit that is basically parallel to the riverbank and can be formed by cast-in-place reinforced concrete walls or masonry embankments. It is used to limit the bandwidth and direction of water flow.

[0041] On the other side of the diversion structure, a water intake structure is constructed. A floodgate 41 is connected to the diversion structure. The gate slot is made of reinforced concrete, and the gate opening is equipped with a liftable gate or a hinged weir gate. During operation, it can discharge upstream water flow and some of the sediment carried downstream. Its other end is integrally connected to the outer wall of the pre-sedimentation tank 422 by cast-in-place concrete, forming a continuous rigid boundary. The water intake weir 421 is located on the side wall of the pre-sedimentation tank 422 and upstream of the floodgate 41. A sand-blocking sill 423 is located downstream of the water intake weir 421. The walls and bottom slab of the pre-sedimentation tank 422 are made of reinforced concrete to ensure overall stability under long-term immersion and scouring conditions. The intake weir 421 is set on the side wall of the pool near the floodgate 41. The width of the weir opening is determined according to the designed water intake flow and is connected to the internal space of the pre-sedimentation pool 422. The sand-blocking embankment 423 is arranged in the pool downstream of the weir opening. It is a low embankment that runs horizontally through the pool. It is reliably connected to the pool wall by reinforced concrete pouring, forming a zone for intercepting and stabilizing the sediment at the bottom of the pre-sedimentation pool 422.

[0042] Under the combined action of the stabilizing structure and the diversion structure, the upstream water flows downstream along the channel between the diversion structure and the floodgate 41. Part of the water flows downstream through the floodgate 41; the other part flows into the pre-sedimentation tank 422 laterally through the intake weir 421 in the relatively calm water area behind the floodgate 41. The flow velocity decreases, and fine suspended particles in the water settle in the pre-sedimentation tank 422. The cleaner water at the top of the pre-sedimentation tank 422 is introduced into the hydropower station's water intake system through the sand-blocking sill 423 to prevent the water from carrying fine suspended particles that could cause wear to the hydropower station's water intake system. Under low water conditions or maintenance conditions, the gate at the intake weir 421 can be temporarily closed and the inflow reduced. After the sediment in the pre-sedimentation tank 422 is cleaned up, operation can be resumed.

[0043] In one embodiment, the bed stabilization structure includes a submerged dam 11, which is buried in the riverbed and whose top elevation is the same as the height of the river channel 2.

[0044] Specifically, the submerged dam 11 is arranged laterally along the direction perpendicular to the main flow of the river channel 2. The dam body is integrally cast with reinforced concrete and buried in the riverbed.

[0045] In one embodiment, the diversion structure includes a diversion wall 31 arranged along the water flow direction of the river channel 2, with the end of the diversion wall 31 near the upstream of the river channel 2 inclined along the side away from the floodgate 41.

[0046] Specifically, the guide wall 31 extends along the direction of the river flow 2, and its height is determined based on the annual water level and protection requirements. The upstream end of the guide wall 31 is arranged in an arc shape with an inclination angle of 10° to 25° away from the floodgate 41 to reduce the intensity of the water flow eddies.

[0047] The upstream water flow is first deflected by the upstream inclined section of the guide wall 31, and the high-energy mainstream is guided to the floodgate 41. The straight section of the guide wall 31 further stabilizes the water flow zone, forming a relatively stable slow flow zone on the water intake side. The risk of direct water flow and bedload inflow is reduced at the water intake weir 421.

[0048] In one embodiment, the bottom elevation of the floodgate 41 is lower than the elevation of the river channel 2, and the slope of the floodgate 41 is greater than the average slope of the bottom of the river channel 2.

[0049] Specifically, the bottom elevation of the flood discharge gate 41 is lower than that of the river channel 2, and the longitudinal slope along the river channel 2 is greater than the average longitudinal slope of the river channel 2 bottom, forming a low-lying, steep-slope flood discharge channel. The upstream section of the gate channel connects smoothly with the natural riverbed, allowing the water flow to accelerate naturally upon entering the flood discharge channel without forming a significant drop, thus avoiding local eddies and energy loss. An energy dissipation zone and apron are installed at the downstream end of the gate channel, continuously connecting with the downstream riverbed to disperse the impact of high-energy flow streams and prevent downstream scouring. The longitudinal slope of the channel bottom allows the water flow to achieve a higher velocity and stronger sediment transport capacity within the flood discharge gate 41, promoting the preferential discharge of bedload carried by the water through the flood discharge gate 41 and preventing it from depositing in the intake weir 421 area or entering the intake system.

[0050] In one embodiment, the bottom elevation of the spillway gate 41 is lower than the top elevation of the intake weir 421.

[0051] Specifically, the floodgate 41 is integrally cast with reinforced concrete, and the gate opening is equipped with a flat gate or an arc-shaped weir gate for scheduling. The end of the floodgate 41 furthest from the diversion structure is connected to the outer wall of the pre-sedimentation pool 422, forming a continuous rigid boundary. To achieve water and sediment separation, the bottom elevation of the floodgate 41 is slightly lower than the top elevation of the intake weir 421, so that the upstream water flow preferentially forms a mainstream channel along the lower bottom of the channel before entering the intake weir 421, carrying larger particle size bedload and high-energy flow streams, and is quickly discharged through the floodgate 41. The intake weir 421 is at a relatively high position, and the water flow enters the pre-sedimentation pool 422 through the intake weir 421. When the upstream water level rises, the floodgate 41 in the lower channel first diverts the water flow containing large particle size bedload, and the flow pattern at the intake weir 421 is less disturbed, ensuring the water intake flow and water quality. During the dry season, the floodgate 41 is used to regulate and maintain the necessary ecological and anti-scour flow.

[0052] In one embodiment, the intake weir 421 is set at an angle to the direction of water flow in the river channel 2.

[0053] Specifically, an intake weir 421 is installed on the side wall of the pre-sedimentation tank 422 near the floodgate 41. The weir line of the intake weir 421 is arranged at a predetermined angle relative to the main flow direction of the river channel 2. When the water flows through the intake weir 421 into the pre-sedimentation tank 422, it can obtain a longitudinal flow velocity and a certain lateral velocity component. The upstream water flow is guided by the intake weir 421 and forms a deflected flow with a lateral velocity component after entering the pre-sedimentation tank 422. A low-velocity zone is formed in front of the sand retaining wall 423, which is conducive to the sedimentation of fine suspended particles and facilitates the subsequent flow of clean water into the water intake system.

[0054] In one embodiment, the sand-blocking embankment 423 is set perpendicular to the water flow direction of the river channel 2, and its two ends are respectively connected to the inner walls of the two sides of the pre-sedimentation tank 422.

[0055] Specifically, a sand-retaining embankment 423 is installed downstream of the pre-sedimentation tank 422. The sand-retaining embankment 423 is arranged laterally perpendicular to the water flow direction of the river channel 2, and its two ends are fixedly connected to the inner walls on both sides of the pre-sedimentation tank 422. The sand-retaining embankment 423 is made of reinforced concrete, and the embankment body is connected to the bottom plate of the tank in a stepped toothed joint. The water-facing side of the embankment body is made with a rounded nose or a small chamfer transition.

[0056] In one embodiment, the top elevation of the sand-blocking embankment 423 is higher than the bottom elevation of the pre-sedimentation tank 422, but lower than the top elevation of the intake weir 421.

[0057] Specifically, after the water flows through the intake weir 421 into the pre-sedimentation tank 422, it first slows down and forms a slow flow near the bottom in front of the sand-blocking sill 423. Since the top of the sand-blocking sill 423 is higher than the bottom elevation of the pre-sedimentation tank 422, the water flows back after hitting the sand-blocking sill 423. Since the top of the sand-blocking sill 423 is lower than the top elevation of the intake weir 421, it will not obstruct the normal water intake of the intake weir 421, nor will it cause a significant flooding effect.

[0058] In one embodiment, the top to the bottom of the sidewall of the pre-sedimentation tank 422 gradually slopes inward and connects to the bottom surface of the pre-sedimentation tank 422.

[0059] Specifically, the walls of the pre-sedimentation tank 422 gradually slope inward from top to bottom, smoothly transitioning to the bottom to form an inward-sloping cross-section. The inward-sloping sidewalls reduce the lateral width at the lower end of the pre-sedimentation tank 422, thereby decreasing the flow velocity and turbulence intensity at the bottom, facilitating the settling of fine suspended particles. The smooth connection between the sidewalls and the bottom prevents stagnation of the water flow, and the deposited suspended particles can also slide naturally along the sloping sidewalls and collect at the bottom.

[0060] In one embodiment, a sand flushing channel 424 is provided on the bottom surface of the pre-sedimentation tank 422, and the sand discharge end of the sand flushing channel 424 passes through the sand retaining wall 423 and is connected to the side wall downstream of the river channel 2.

[0061] Specifically, a flushing channel 424 extending downstream of the river channel 2 is provided on the bottom surface of the pre-sedimentation tank 422. An embedded sand discharge port is provided on the sand retaining wall 423. The flushing channel 424 passes through the sand retaining wall 423, so that the sand discharge end of the flushing channel 424 passes through the sand retaining wall 423 and connects with the downstream side wall of the river channel 2. The lateral sides of the flushing channel 424 smoothly transition to the rounded curved surface of the tank bottom to ensure stability and directionality during sand discharge. An openable and closable gate or valve is provided at the sand discharge port. When opened, the sediment deposited in front of the sand retaining wall 423 at the bottom of the tank can be discharged smoothly with the flushing channel 424.

[0062] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A water intake structure for a multi-sediment bedload river channel, characterized in that, include: A bed stabilization structure is set perpendicular to the water flow direction of the river channel (2), and one end of the bed stabilization structure is connected to one side of the river channel (2). A diversion structure is arranged along the water flow direction of the river channel (2), and one side of the diversion structure is connected to the other end of the bed stabilization structure; The water intake structure includes a floodgate (41) and a water intake assembly. One end of the floodgate (41) is connected to the other side of the diversion structure. The water intake assembly includes a water intake weir (421), a pre-sedimentation tank (422), and a sand-blocking sill (423). The pre-sedimentation tank (422) is located on the other side of the river channel (2). The other end of the floodgate (41) is connected to the outer wall of the pre-sedimentation tank (422). The water intake weir (421) is provided on the side of the pre-sedimentation tank (422) near the floodgate (41), and the water intake weir (421) is located upstream of the pre-sedimentation tank (422). The sand-blocking sill (423) is provided downstream of the pre-sedimentation tank (422). The diversion structure includes a diversion wall (31) arranged along the water flow direction of the river channel (2), and the end of the diversion wall (31) near the upstream of the river channel (2) is inclined along the side away from the floodgate (41). The water intake weir (421) is set at an angle to the water flow direction of the river channel (2); The bottom elevation of the floodgate (41) is lower than the top elevation of the intake weir (421).

2. The water intake structure for multi-sediment bedload channels according to claim 1, characterized in that, The sand-blocking embankment (423) is set perpendicular to the water flow direction of the river channel (2), and its two ends are respectively connected to the inner walls of the two sides of the pre-sedimentation tank (422).

3. The water intake structure for multi-sediment bedload channels according to claim 2, characterized in that, The top elevation of the sand-blocking embankment (423) is higher than the bottom elevation of the pre-sedimentation tank (422) and lower than the top elevation of the water intake weir (421).

4. The water intake structure for multi-sediment bedload channels according to claim 3, characterized in that, The top of the side wall of the pre-settling tank (422) gradually slopes inward to the bottom of the side wall and connects to the bottom surface of the pre-settling tank (422).

5. The water intake structure for multi-sediment bedload channels according to claim 4, characterized in that, The bottom surface of the pre-sedimentation tank (422) is provided with a sand flushing channel (424), and the sand discharge end of the sand flushing channel (424) passes through the sand retaining wall (423) and is connected to the side wall of the downstream of the river channel (2).

6. The water intake structure for multi-sediment bedload channels according to claim 1, characterized in that, The bottom elevation of the floodgate (41) is lower than the elevation of the river channel (2), and the slope of the floodgate (41) is greater than the average slope of the bottom of the river channel (2).

7. The water intake structure for multi-sediment bedload channels according to claim 1, characterized in that, The stabilizing structure includes a submerged dam (11), which is buried in the riverbed and has the same top elevation as the river channel (2).

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