Sand blocking and guiding system and method for water power removal of water inlet of hydropower station
By designing a sand-blocking and sand-guiding system at the intake of the hydropower station, the silt is automatically cleared using water flow dynamics, solving the blockage problem caused by silt accumulation and achieving efficient and low-cost dredging results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-22
- Publication Date
- 2026-03-13
AI Technical Summary
Bedload silt is prone to accumulate at the water intake of hydropower stations, which can clog trash racks, affect water intake efficiency, and damage equipment. Existing dredging methods are costly and require interruption of power generation or water supply.
Design a sand-blocking and sand-guiding system, including a sand-blocking sill and a longitudinal guide wall. The sand-blocking sill is set at an angle to the main direction of the river channel to form a flow guiding channel. It uses water flow dynamics to automatically clear silt and sand, and combines it with a discharge and sand flushing gate to achieve efficient dredging.
It enables automatic interception and cleaning of bedload silt under different flow conditions, avoiding siltation, reducing dredging costs, and ensuring normal power generation or water supply operations.
Smart Images
Figure CN121654072A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of water conservancy and hydropower engineering technology, and more specifically, to a sand-blocking and sand-guiding system and method for hydraulic dredging at the intake of a hydropower station. Background Technology
[0002] In river water intake projects, bedload sediment (mainly including pebbles, gravel and coarse sand) accumulates continuously at the water intake front of hydropower stations, which can easily clog trash racks and seriously affect water intake efficiency. Once it enters the water conveyance system with the water flow, it will cause severe wear and tear on key equipment such as turbines and pumps of hydropower stations, resulting in reduced equipment efficiency, frequent malfunctions, shortened downtime maintenance cycles, and high maintenance and replacement costs.
[0003] In related technologies, sand-blocking dikes (or sand-guiding dikes) are commonly used as the main measure to prevent land displacement. Traditional sand-blocking dikes adopt a straight gravity solid structure, which can play a certain role in blocking the flow of sediment. However, the sediment accumulated in front of the dike cannot be effectively discharged by the structure itself and the power of water flow. It is necessary to rely on mechanical dredging or special hydraulic flushing facilities (such as flushing gates) for cleaning. This not only has high operating costs, but the dredging process often requires the interruption of normal power generation or water supply, which affects the benefits of the project. Summary of the Invention
[0004] The problem solved by this invention is how to achieve low-cost automatic cleaning of bedload sediment carried by the main stream in the river channel upstream of the power plant intake.
[0005] To address the aforementioned problems, this invention provides a sand-blocking and sand-guiding system and method for hydraulic dredging at the intake of a hydropower station.
[0006] In a first aspect, the present invention provides a sediment-trapping and sand-guiding system for hydraulic dredging at the intake of a hydropower station, applied to the power station, which includes a powerhouse and a spillway / sand flushing gate arranged at intervals. The sediment-trapping and sand-guiding system for hydraulic dredging at the intake of the hydropower station includes a sediment-trapping sill and a longitudinal guide wall. One end of the sediment-trapping sill is connected to a rocky bank slope, and the end of the sediment-trapping sill away from the rocky bank slope is connected to one end of the longitudinal guide wall. The sediment-trapping sill is configured to be set at an angle to the mainstream direction of the river channel. The end of the longitudinal guide wall away from the sediment-trapping sill is connected to the interval between the powerhouse and the spillway / sand flushing gate. The upstream surface of the sediment-trapping sill and the longitudinal guide wall form a guiding channel for guiding and displacing sediment.
[0007] Optionally, the sand-blocking embankment is configured to form an angle between 30° and 45° with the main flow direction of the river channel.
[0008] Optionally, the sand-blocking embankment includes a waterstop and a plurality of sand-blocking embankment bodies spaced apart along its length, with an expansion joint formed between two adjacent sand-blocking embankment bodies, and the waterstop is fixedly installed in the expansion joint.
[0009] Optionally, the main body of the sand-blocking embankment includes a wall and a cantilever slab. The wall is fixed to the foundation, and the cantilever slab is fixed to the top of the wall. The cantilever slab extends toward the water-facing side of the wall. The thickness of the cantilever slab gradually decreases from the end closest to the wall to the end furthest from the wall.
[0010] Optionally, the sand-blocking and guiding system for hydraulic dredging at the intake of a hydropower station also includes a protective cap, which is installed at the connection between the sand-blocking sill and the longitudinal guide wall.
[0011] Optionally, the thickness of the wall gradually increases from the top end to the bottom end.
[0012] Optionally, the main body of the sand-retaining embankment also includes anchor bars, a portion of which is fixedly inserted into the wall, and the other portion of which is fixedly inserted into the foundation.
[0013] Optionally, the main body of the sand-blocking embankment further includes a first protective body and a second protective body. The first protective body is disposed on the water-facing side of the wall and is used to connect with the foundation and the bottom of the water-facing surface of the wall. The second protective body is disposed on the backwater side of the wall and is used to connect with the bottom of the backwater side of the foundation and the wall.
[0014] Optionally, the thickness of the top end of the wall is the same as the thickness of the bottom end of the wall.
[0015] Optionally, the main body of the sand-blocking embankment further includes a toe plate and a heel plate, wherein the toe plate is fixedly connected to the bottom of the water-facing side of the wall, and the heel plate is fixedly connected to the bottom of the back side of the wall; The length of the wall toe slab is greater than or equal to half the length of the cantilever slab.
[0016] Optionally, the main body of the sand-trapping embankment also includes a plurality of ribs, which are spaced apart along the length of the main body of the sand-trapping embankment and are fixedly disposed at the connection between the wall and the wall heel plate.
[0017] Optionally, the sand-blocking and sand-guiding system for hydraulic dredging at the intake of a hydropower station also includes a third protective body, which is located on the water-facing side of the wall and covers the foundation.
[0018] Optionally, the sand-blocking and sand-guiding system for hydraulic dredging at the intake of a hydropower station also includes backfilled stone slag and a fourth protective body installed on the backwater side of the wall. The backfilled stone slag covers the backwater surface of the wall and the rib plate, and the fourth protective body is installed above the backfilled stone slag and is flush with the top surface of the cantilever plate.
[0019] Secondly, the present invention provides a method for intercepting and guiding sand in hydraulic dredging at the intake of a hydropower station, based on the sand intercepting and guiding system for hydraulic dredging at the intake of a hydropower station as described above, comprising the following steps: Before the bedload sediment carried by the main stream of the river reaches the intake of the power plant, it is intercepted by a sediment trap. The sediment trap is configured at an angle to the direction of the main stream of the river to reduce the cross-section of the main stream in the river below the top of the sediment trap and increase the bottom flow velocity of the sediment trap. The increased velocity of the underflow flows along the extension direction of the sand-blocking embankment, generating a sand-carrying force pointing towards the discharge and flushing gate; under the combined action of the increased velocity of the underflow and the sand-carrying force, the intercepted bedload sediment is pushed along the guide channel towards the discharge and flushing gate. When the flood season arrives and the main flow of the river increases, the overall velocity of the main flow in front of the sand-blocking sluice further increases, and the sand-discharging efficiency of the sand-blocking and guiding system used for hydraulic dredging at the intake of the hydropower station is enhanced accordingly. The bedload sediment that is guided to the vicinity of the top of the sand-blocking sluice is blocked by the top of the sand-blocking sluice. Under the push of the increased main flow velocity, the bedload sediment accelerates to move along the bottom flow direction of the river channel and is discharged to the downstream side of the spillway and sand-flushing gate.
[0020] The beneficial effects of the sand-blocking and sand-guiding system and method for hydraulic dredging at the intake of a hydropower station of the present invention are as follows: One end of the sand-retaining sluice is connected to the rocky bank slope along the edge of the river channel, and the other end of the sand-retaining sluice points towards the spillway and is connected to one end of the longitudinal guide wall. The sand-retaining sluice is configured at an angle to the main flow direction of the river channel, so that the sand-retaining sluice forms an asymmetrical and directional inflow boundary at the inlet of the power plant and reduces the cross-section of the main flow in the river channel below the top of the sand-retaining sluice. This not only intercepts the bedload sediment carried by the main flow and guides the intercepted bedload sediment to flow along the extension direction of the sand-retaining sluice, generating a sediment-carrying force towards the spillway and spillway, but also increases the bottom flow velocity of the sand-retaining sluice due to the reduced cross-section of the main flow in the river channel below the top of the sand-retaining sluice. Under the combined action of the increased bottom flow velocity and the sediment-carrying force, the intercepted bedload sediment is pushed towards the spillway and spillway.
[0021] Since the two ends of the longitudinal guide wall are respectively connected to the sand-blocking sill and the interval between the power plant and the spillway and sand-flushing gate, the upstream side of the longitudinal guide wall and the sand-blocking sill together form a flow channel similar to an "L" or "trumpet" shape, so as to use the flow channel to continuously and directly guide the collected sediment to the upstream side of the spillway and sand-flushing gate.
[0022] When the flood season arrives and the main flow of the river increases, the overall velocity of the main flow in front of the sand-blocking sluice further increases. Consequently, the sand-clearing efficiency of the sand-blocking and guiding system used for hydraulic dredging at the hydropower station intake is enhanced. The bedload sediment guided to the vicinity of the top of the sand-blocking sluice is blocked by the top of the sluice. Driven by the increased main flow velocity, the bedload sediment accelerates its movement along the bottom flow direction of the river. When dredging is required, simply opening the discharge and flushing gates allows the bedload sediment carried in the main flow of the river to be flushed away. The sediment is discharged downstream of the spillway and flushing gate. Through the cooperation of the sand-blocking sluice, longitudinal guide wall, power plant and spillway and flushing gate, the dynamic balance of bedload sediment in front of the sand-blocking sluice can be automatically maintained under different flow conditions, effectively preventing siltation. It realizes automatic and effective interception of bedload sediment carried by the main stream in the river and efficient dredging operation. It does not require mechanical dredging or special hydraulic flushing facilities to clean the sediment, effectively reducing dredging costs and ensuring normal power generation or water supply operation. Attached Figure Description
[0023] Figure 1 This is a partial structural diagram of the power station in an embodiment of the present invention; Figure 2 for Figure 1 One of the schematic diagrams of the cross-sectional structure along section line AA; Figure 3 for Figure 1 One of the schematic diagrams of the cross-sectional structure along section line BB; Figure 4 This is one of the structural schematic diagrams of a sand-trapping embankment in one embodiment of the present invention; Figure 5 This is a second schematic diagram of the structure of a sand-trapping embankment in one embodiment of the present invention; Figure 6 Schematic diagram of the cross-sectional structure along section line AA (Part 2); Figure 7 for Figure 1 Schematic diagram of the cross-sectional structure along section line BB (Part 2); Figure 8 This is one of the structural schematic diagrams of a sand-trapping embankment in another embodiment of the present invention; Figure 9 This is a second schematic diagram of the structure of the sand-trapping embankment in another embodiment of the present invention; Figure 10This is a schematic diagram of a sand-blocking and sand-guiding system for hydraulic dredging at the intake of a hydropower station, according to another embodiment of the present invention.
[0024] Explanation of reference numerals in the attached figures: 1-Sand retaining wall; 100-Expansion joint; 11-Waterstop; 12-Sand retaining wall main body; 121-Wall; 122-Cantilever slab; 123-Anchor bar; 124-First protective body; 125-Second protective body; 126-Toe slab; 127-Heel slab; 128-Rib plate; 2-Longitudinal guide wall; 3-Power plant building; 4-Spill and sand flushing gate; 5-River channel; 51-Rock bank slope; 6-Bedbed sediment; 7-Protective head; 8-Third protective body; 9-Backfill with gravel; 10-Fourth protective body; 200-Foundation. Detailed Implementation
[0025] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.
[0026] In the accompanying drawings, the X-axis represents left and right positions, with the positive direction of the X-axis representing the right side and the negative direction representing the left side; the Z-axis represents up and down positions, with the positive direction of the Z-axis representing the top and the negative direction representing the bottom. It should be noted that the aforementioned representations of the X and Z axes are merely for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.
[0027] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first," "second," etc., mentioned in this invention are used only to distinguish different devices, modules, or units, and are not intended to limit the order of functions performed by these devices, modules, or units or their interdependencies.
[0028] It should be noted that the terms "a" and "a plurality of" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".
[0029] like Figure 1 As shown in the figure, an embodiment of the present invention provides a sand-blocking and sand-guiding system for hydraulic dredging at the intake of a hydropower station. The system is applied to the power station, which includes a powerhouse 3 and a spillway and sand-flushing gate 4 arranged at intervals. The sand-blocking and sand-guiding system for hydraulic dredging at the intake of the hydropower station includes a sand-blocking sill 1 and a longitudinal guide wall 2. One end of the sand-blocking sill 1 is connected to a rocky bank slope 51, and the end of the sand-blocking sill 1 away from the rocky bank slope 51 is connected to one end of the longitudinal guide wall 2. The sand-blocking sill 1 is configured to be set at an angle to the mainstream direction of the river channel 5. The end of the longitudinal guide wall 2 away from the sand-blocking sill 1 is connected to the powerhouse 3 and the spillway and sand-flushing gate 4 at intervals. The water-facing surface of the sand-blocking sill 1 and the longitudinal guide wall 2 form a guiding channel for guiding the displacement of sediment 6.
[0030] Specifically, the rocky bank slope 51 may be one of the outer edges of the channel 5; the channel 5 is used to transport the main stream carrying bedload sediment 6.
[0031] The angle between the sand-blocking embankment 1 and the main direction of the river channel 5 can be represented by "α". The angle α can be an acute angle, so that the sand-blocking embankment 1 is inclined relative to the main direction of the river channel 5.
[0032] The longitudinal guide wall 2 is parallel to the main direction of the river channel 5, and the opposite ends of the longitudinal guide wall 2 are respectively sealed and connected to the sand-blocking embankment 1 and the power plant 3 and the discharge and sand-flushing gate 4 at the interval.
[0033] Since the power plant 3 and the spillway and sand flushing gate 4 are spaced apart, the longitudinal guide wall 2 is connected to the spaced-apart end away from the sand-blocking sill 1.
[0034] The direction of the main current in the river channel 5 towards the sand-blocking embankment 1 is the water-facing side of the sand-blocking embankment 1.
[0035] In this embodiment, one end of the sand-retaining dam 1 is connected to the rocky bank slope 51 along the edge of the river channel 5, and the other end of the sand-retaining dam 1 points towards the spillway and flushing gate 4 and is connected to one end of the longitudinal guide wall 2. The sand-retaining dam 1 is configured to be set at an angle to the mainstream direction of the river channel 5, so that the sand-retaining dam 1 forms an asymmetrical and directional inflow boundary at the inlet of the river channel 5 and the power plant 3, and reduces the cross-section of the mainstream in the river channel 5 below the top of the sand-retaining dam 1. This not only intercepts the bedload sediment 6 carried by the mainstream and guides the intercepted bedload sediment 6 to flow along the extension direction of the sand-retaining dam 1, generating a sediment-carrying force pointing towards the spillway and flushing gate 4, but also increases the bottom flow velocity of the sand-retaining dam 1 due to the reduction of the cross-section of the mainstream in the river channel 5 below the top of the sand-retaining dam 1. Under the combined action of the increased flow velocity of the bottom flow and the sediment-carrying force, the intercepted bedload sediment 6 is pushed towards the spillway and flushing gate 4.
[0036] Since the two ends of the longitudinal guide wall 2 are respectively connected to the sand-blocking sill 11 and the power plant 3 and the discharge sand-flushing gate 4, the longitudinal guide wall 2 and the water-facing surface of the sand-blocking sill 1 together form a flow channel similar to an "L" or "trumpet" shape, so as to use the flow channel to continuously and directly guide the collected sediment to the upstream side of the discharge sand-flushing gate 4.
[0037] When the flood season arrives and the main flow of river channel 5 increases, the overall velocity of the main flow in front of the sand-blocking sill 1 further increases. Consequently, the sand-clearing efficiency of the sand-blocking and guiding system used for hydraulic dredging at the hydropower station intake is enhanced. The bedload sediment 6, guided to the vicinity of the top of the sand-blocking sill 1, is blocked by the top of the sill 1. Driven by the increased main flow velocity, the bedload sediment 6 accelerates its movement along the bottom flow direction of river channel 5. When dredging is required, simply opening the discharge and flushing gate 4 allows the bedload sediment 6 carried in the main flow of river channel 5 to be flushed away. The sediment is discharged downstream of the discharge and flushing gate 4. Through the cooperation of the sand-blocking sill 1, the longitudinal guide wall 2, the power plant 3, and the discharge and flushing gate 4, the dynamic balance of the bedload sediment 6 in front of the sand-blocking sill 1 can be automatically maintained under different flow conditions, effectively preventing siltation. This achieves automatic and effective interception and efficient dredging of the bedload sediment 6 carried by the main stream in the river channel 5, without relying on mechanical dredging or special hydraulic flushing facilities to clean the sediment, effectively reducing dredging costs and ensuring normal power generation or water supply operations.
[0038] Optionally, combined Figure 1 As shown, the sand-blocking embankment 1 is configured such that the angle between it and the main flow direction of the river channel 5 ranges from 30° to 45°.
[0039] Specifically, the sand-blocking embankment 1 is configured such that the angle between it and the main flow direction of the river channel 5 can be selected within the range of 30° to 45°.
[0040] In this optional embodiment, if the angle between the sand-retaining dam 1 and the mainstream direction is too small (e.g., <30°), its lateral interception component is insufficient, and the sediment is likely to slide or bypass along the front of the sand-retaining dam 1, resulting in low interception efficiency. Alternatively, if the angle is too small, the length of the sand-retaining dam will be large, the amount of engineering work will be large, the investment will be increased, or the engineering layout will be restricted. If the angle is too large (e.g., >45°), it will form a near-vertical barrier. Although the interception force is strong, the water flow impact is violent and the energy loss is large. Furthermore, the sediment is likely to accumulate in the still water area in front of the sand-retaining dam 1, which is not conducive to guidance, causing the sediment to roll over the sand-retaining dam and reducing or losing its sand-retaining and guiding function.
[0041] The included angle range of 30° to 45° ensures that the sand-retaining embankment 1 has a sufficient component in the normal direction to effectively intercept bedload sediment 6, while generating a stable and sufficiently strong water flow component along the sand-retaining embankment 1 in the tangential direction. This component can continuously push the intercepted sediment along the water-facing side of the sand-retaining embankment 1 towards the longitudinal guide wall 2, thereby achieving the best balance between "interception" and "transportation" and preventing sediment from accumulating in front of the embankment to the overturning height.
[0042] In related technologies, if a traditional sand-trapping embankment is a long-distance continuous solid structure, stress will be generated inside it under the influence of temperature changes and uneven settlement of the foundation, which will easily lead to structural cracking.
[0043] Optionally, combined Figure 2 , Figure 4 , Figure 5 , Figure 6 , Figure 8 and Figure 9 As shown, the sand-blocking embankment 1 includes a water-stopping strip 11 and a plurality of sand-blocking embankment bodies 12 spaced apart along its length. An expansion joint 100 is formed between two adjacent sand-blocking embankment bodies 12, and the water-stopping strip 11 is fixedly installed in the expansion joint 100.
[0044] Specifically, the waterstop 11 can be made of rubber material.
[0045] The length direction of the sand-retaining embankment 1 refers to the direction in which the sand-retaining embankment 1 extends. Multiple sand-retaining embankment bodies 12 can be distributed at intervals along the direction in which the sand-retaining embankment 1 extends.
[0046] In this optional embodiment, the sand-retaining embankment 1 is configured as a multi-segment sand-retaining embankment body 12, and an expansion joint 100 is formed between adjacent sand-retaining embankment body segments 12. Each segment of the embankment body can independently undergo slight displacement or deformation, effectively releasing temperature stress and uneven settlement stress, preventing through cracks or structural damage to the sand-retaining embankment 1 due to stress concentration, and greatly improving the adaptability and durability of the structure. A waterstop 11 is fixedly installed in the expansion joint 100 to prevent water and silt from seeping or scouring through the gap, protecting the stability of the foundation. Thus, while achieving structural flexibility, it ensures the reliability and safety of its long-term operation and reduces the maintenance requirements caused by the hollowing out of the foundation 200.
[0047] Optionally, combined Figures 2 to 5 , Figures 6 to 9 As shown, the main body 12 of the sand-blocking embankment includes a wall 121 and a cantilever slab 122. The wall 121 is fixed to the foundation 200, and the cantilever slab 122 is fixed to the top of the wall 121. The cantilever slab 122 extends toward the water-facing side of the wall 121. The thickness of the cantilever slab 122 gradually decreases from the end closest to the wall 121 to the end furthest from the wall 121.
[0048] Specifically, the bottom of the wall 121 can be fixedly connected to the foundation 200; the wall 121 can extend vertically, and the cantilever slab 122 can extend horizontally. The cantilever slab 122 and the wall 121 can be cast together with concrete to form the main body 12 of the sand retaining embankment.
[0049] 122 cantilever slab Figure 2 The dimension along the Z-axis in the coordinate system is the thickness of the cantilever plate 122.
[0050] In this optional embodiment, the wall 121 serves as the main load-bearing and stabilizing structure, responsible for resisting the soil and water pressure behind it and transmitting it to the foundation 200; the cantilever slab 122, as a functional extension component, is mainly responsible for direct interaction with water flow and sediment; the cantilever slab 122 extends horizontally towards the water-facing side (i.e., the direction of incoming flow), forming a narrow, confined space between its lower surface and the riverbed. When the water flow impacts the sediment-trapping sill 1, some of the water flow (especially the sediment-laden water flow at the bottom) is forced to pass through the space under the cantilever slab 122. The cantilever slab 122 acts like an "eaves" covering the flow channel. This structure can more effectively guide and gather the sediment-rich water flow at the bottom, causing it to move in a predetermined direction (i.e., the flow channel described in technical solution 1), enhancing the system's ability to capture and transport bottom bedload sediment 6, and improving the accuracy and efficiency of sediment guidance.
[0051] The thickness of the cantilever slab 122 gradually decreases from the end near the wall 121 to the end away from the wall 121. The thickness is designed to gradually decrease from the root to the free end, so that the material distribution matches the internal force distribution. The lower surface of the cantilever slab 122 forms a smoothly transitioning slope. When water flows under the slab, this gradual contour can reduce water flow separation and avoid the generation of large-scale vortices under the cantilever slab 122.
[0052] Furthermore, while ensuring that the root of the cantilever slab 122 has sufficient strength to withstand the impact of water flow and its own weight bending moment, the material is effectively reduced by gradually thinning towards the free end, thereby reducing unnecessary materials, structural weight and construction costs.
[0053] Optionally, combined Figures 2 to 5 , Figures 6 to 9 As shown, the sand-blocking and sand-guiding system used for hydraulic dredging at the intake of a hydropower station also includes a protective cap 7, which is installed at the connection between the sand-blocking sill 1 and the longitudinal guide wall 2.
[0054] Specifically, the protective head wrap 7 can be constructed using riprap, reinforced gabions, or concrete.
[0055] In this optional embodiment, since the connection between the sand-retaining embankment 1 and the longitudinal guide wall 2 will be subjected to concentrated impact and deflection by high-speed water flow and a large amount of bedload silt 6 (pebbles, gravel), a protective cap 7 is provided at the connection between the sand-retaining embankment 1 and the longitudinal guide wall 2. This can strengthen, protect and optimize the shape of the connection between the sand-retaining embankment 1 and the longitudinal guide wall 2. The protective cap 7 directly bears and disperses the concentrated impact of water flow and silt, which effectively prevents the concrete at the connection from cracking, peeling or the reinforcing steel from being exposed, thus protecting the integrity of the main structure.
[0056] Furthermore, the outer wall of the protective cap 7 can be in the form of an arc or semi-circle. The protective cap 7 can make the water flow and sediment turn more smoothly at this point, reducing turbulence, eddies and water flow separation, thereby reducing the risk of local scouring and head loss, and making the sand guiding process smoother.
[0057] Optionally, combined Figures 2 to 5 As shown, the thickness of the wall 121 gradually increases from the top end to the bottom end.
[0058] Specifically, Figures 2 to 5 The main body 12 of the sand-retaining embankment is mainly suitable for foundations 200 with rocks (i.e., rock foundations).
[0059] Wall 121 along Figure 2 The dimension along the X-axis in the coordinate system is the thickness of wall 121.
[0060] The thickness of the wall 121 gradually increases from the top to the bottom, so that the wall 121 can be in the form of a "gravity wall".
[0061] In this optional embodiment, the river water pressure from the upstream side (the diversion channel side) is proportional to the water depth, meaning the pressure is greater closer to the bottom of the riverbed. The backfill soil pressure from the downstream side (the bank side) also follows the same rule of greater pressure at the bottom. The bending moment and shear force borne by the wall 121 reach their maximum values at the bottom (near the foundation 200) and decrease towards the top.
[0062] Designing the wall with a variable cross-section that is thicker at the bottom and thinner at the top is key to ensuring that the structure's section modulus (resistance to bending) and cross-sectional area (resistance to shear and compression) vary along the height in accordance with the distribution of internal forces it experiences. The larger bottom section provides significant bending and shear resistance, while the smaller top section is sufficient to withstand less intense internal forces. This avoids using excessive material in the less stressed top region, concentrating material in the most stressful, critical area (the bottom), directly reducing project costs and material consumption.
[0063] Optionally, combined Figures 3 to 5 As shown, the main body 12 of the sand-blocking embankment also includes anchor bars 123. A portion of the anchor bars 123 is fixedly inserted into the wall 121, and the other portion of the anchor bars 123 is fixedly inserted into the foundation 200.
[0064] Specifically, the diameter of the anchor bar 123 can be in the range of φ22~φ25.
[0065] The main body 12 of the sand-retaining embankment may include multiple anchor bars 123, and the spacing between two adjacent anchor bars 123 may be 2.0m. The length of the anchor bar 123 may be 2.0m, and a part of the anchor bar 123, for example 1m, is used to anchor into the wall 121, and another part of the anchor bar 123, for example 1m, is used to be embedded into the foundation 200.
[0066] In this optional embodiment, if the wall 121 rests on the foundation 200 solely by its own weight and bottom friction, the connection is a passive contact. Faced with the continuous, pulsating water flow impact from the systematic flow guidance described in technical solution 1, the water flow impact may cause the wall 121 to slide along the surface of the foundation 200. Therefore, anchor bars 123 are installed, and their two ends are anchored (cast or grouted) to the concrete of the wall 121 and the rock mass of the foundation 200, respectively. This is equivalent to installing "shear pins" and "tension bars" between the two. The tension provided by the anchor bars 123 can directly resist the moment that would cause the wall 121 to overturn or be pulled upwards from the bottom. This allows the wall 121 to more effectively convert the load from the top cantilever slab 122 and the bending moment it bears into pressure on the foundation 200 and tension on the anchor bars 123, forming a balanced force system and significantly improving the structure's overturning safety factor. Through the force transmission of anchor bars 123, the concentrated force is more evenly distributed to the foundation 200, reducing local compressive and tensile stresses on the contact surface of the foundation 200. This prevents the leading edge of the foundation 200 from being crushed or cracked due to excessive stress, thus protecting the bearing capacity of the foundation. Facing dynamic and impact loads such as floods and mudslides during the flood season, the rigid anchoring connection allows the wall 121 and the foundation 200 to work together and deform together, avoiding relative displacement at the connection point and the resulting fatigue failure, ensuring the integrity and reliability of the structure during long-term operation.
[0067] Optionally, combined Figure 4 and Figure 5 As shown, the main body 12 of the sand-blocking embankment also includes a first protective body 124 and a second protective body 125. The first protective body 124 is disposed on the water-facing side of the wall 121 and is used to connect with the foundation 200 and the bottom of the water-facing surface of the wall 121. The second protective body 125 is disposed on the backwater side of the wall 121, and the second protective body 125 is used to connect with the foundation 200 and the bottom of the backwater side of the wall 121.
[0068] Specifically, the first protective body 124 and the second protective body 125 can both be constructed of riprap, reinforced gabions, or concrete.
[0069] A first protective body 124 and a second protective body 125 can be installed at the foundation 200 on the water-facing side and the back side of the wall 121, respectively.
[0070] Wall 121 along Figure 2 In the coordinate system, the side opposite to the X-axis is the water-facing side of wall 121, which can also be understood as the side in contact with the water flow; wall 121 along Figure 2 The side with the positive X-axis in the coordinate system is the backwater side of wall 121.
[0071] In this optional embodiment, the first protective body 124 is connected to the bottom of the water-facing side of the foundation 200 and the wall 121, and the second protective body 125 is connected to the bottom of the backwater side of the foundation 200 and the wall 121. This is equivalent to strengthening the connection area between the wall 121 and the foundation 200 from the opposite sides through the first protective body 124 and the second protective body 125. This not only improves the erosion protection effect of the water-facing foundation of the sand-blocking embankment 12, but also improves the connection stability between the foundation 200 and the wall 121.
[0072] Optionally, combined Figures 6 to 9 As shown, the thickness of the top end of the wall 121 is the same as the thickness of the bottom end of the wall 121.
[0073] Specifically, Figures 6 to 9 The foundation 200 of the main body 12 of the sand-retaining embankment shown is a non-rock foundation.
[0074] Wall 121 along Figure 9 The dimension along the X-axis of the coordinate system is the thickness of wall 121. The thickness of the top end of wall 121 is the same as the thickness of the bottom end of wall 121, so that wall 121 can basically form a cuboid structure, and wall 121 can be a straight wall structure.
[0075] In this optional embodiment, the top and bottom of the wall 121 have the same thickness, so that the shape of the wall 121 can be a standard cuboid structure. The wall 121 with the same thickness means that the formwork is of a single type and can be reused. The formwork, reinforcement and concrete pouring processes are greatly simplified, which can greatly improve construction efficiency, shorten the construction period, and reduce construction complexity and error probability.
[0076] Optionally, combined Figure 6 and Figure 9 As shown, the main body 12 of the sand-blocking embankment also includes a toe plate 126 and a heel plate 127. The toe plate 126 is fixedly connected to the bottom of the water-facing side of the wall 121, and the heel plate 127 is fixedly connected to the bottom of the back side of the wall 121. The length of the wall toe plate 126 is greater than or equal to half the length of the cantilever plate 122.
[0077] Specifically, the wall toe plate 126 along Figure 6 In the coordinate system, the dimension along the X-axis is the length of the wall toe slab 126; similarly, the dimension along the cantilever slab 122 is... Figure 6 The dimension along the X-axis in the coordinate system is the length of the cantilever plate 122.
[0078] In this optional embodiment, if the wall 121 is connected to the foundation 200 only through its narrow and thick bottom surface, a huge concentrated compressive stress will be generated in this area, which may exceed the bearing capacity of the foundation or increase the tendency of the wall to overturn forward. Therefore, a horizontally extending plate (such as wall toe plate 126) is added to the bottom of the water-facing side of the wall 121, and a horizontally extending plate (such as wall heel plate 127) is added to the bottom of the backwater side of the wall 121 to distribute the upper load of the wall 121 to the larger foundation 200. The wall toe plate 126 acts as a "front crowbar", and the wall heel plate 127 acts as a "rear crowbar", together forming a lever arm to resist the overturning of the wall 121. This makes the pressure distribution on the foundation 200 of the sand-retaining embankment 12 more uniform and avoids stress concentration.
[0079] The toe slab 126 and heel slab 127 significantly increase the lever arm of the stabilizing moment. The overturning moment generated by the water flow impact and the load of the cantilever slab 122 is effectively balanced by the stabilizing moment composed of the foundation reaction force 200 under the toe slab 126 and the backfill pressure (or anchoring force) on the heel slab 127, which greatly improves the safety factor of the structure.
[0080] The load is transferred to the foundation through a larger base plate area (i.e., wall toe plate 126 and wall heel plate 127), which significantly reduces the foundation compressive stress per unit area and ensures that the foundation bearing capacity meets the requirements. At the same time, wall toe plate 126 and wall heel plate 127 help to change the stress distribution from the concentrated state at the bottom of the wall 121 to a more uniform state, preventing the front edge of the foundation 200 from being crushed due to excessive pressure.
[0081] The length of the wall toe plate 126 is greater than or equal to half the length of the cantilever plate 122, which fundamentally ensures that the size of the wall toe plate 126 is sufficient to resist most of the overturning effect generated by the cantilever plate 122, and avoids the hidden instability risk caused by the wall toe plate 126 being too short.
[0082] Optionally, combined Figures 7 to 9 As shown, the main body 12 of the sand-blocking embankment also includes a plurality of ribs 128, which are distributed at intervals along the length of the main body 12 of the sand-blocking embankment. The ribs 128 are fixedly installed at the connection between the wall 121 and the wall heel plate 127.
[0083] Specifically, the rib 128 can adopt a trapezoidal structure or a triangular structure.
[0084] The rib plate 128, the wall 121, and the wall heel plate 127 can be fixed into a single structure by integral molding.
[0085] In this optional embodiment, the rib plate 128 provides an additional concrete section for the right-angle corner of the wall 121 and the wall heel plate 127, significantly improving the area's resistance to tensile and shear stresses. This effectively prevents cracks from forming and spreading under long-term alternating loads, ensuring the structural integrity and durability. As a stiffening support for the wall heel plate 127, the rib plate 128 transforms the wall heel plate 127 from a simple cantilever plate into a locally reinforced rib-beam plate system. This significantly reduces the vertical deflection (deformation) of the wall heel plate 127 under earth pressure and upper loads, enabling it to more effectively bear and diffuse foundation stress.
[0086] Optionally, combined Figure 10 As shown, the sand-blocking and sand-guiding system for hydraulic removal at the intake of a hydropower station also includes a third protective body 8, which is located on the water-facing side of the wall 121 and covers the foundation 200.
[0087] Specifically, the third protective structure 8 may be made of reinforced gabions and / or large stones.
[0088] In this optional embodiment, the toe plate 126 at the bottom of the water-facing side of the wall 121 becomes the primary impact point and abrasion surface for the guided bedload sediment 6 (pebbles, gravel) moving along the riverbed. The water flow may generate complex around-flow at the front end of the toe plate 126, exacerbating localized scouring of the foundation 200 below it, thus affecting the lifespan of the toe plate 126. Therefore, a third protective body 8 is provided on the water-facing side of the wall 121, strategically extending and expanding the protection range to the foundation 200 on the water-facing side of the wall 121. This "coverage" means that it forms a physical protective layer and buffer for the foundation 200 on the water-facing side of the wall 121, directly bearing and dissipating impact energy, while simultaneously suppressing and altering the around-flow pattern at the front end of the toe plate 126 through its volume.
[0089] Optionally, combined Figure 10 As shown, the sand-blocking and sand-guiding system for hydraulic dredging at the intake of a hydropower station also includes backfill stone slag 9 and a fourth protective body 10 installed on the backwater side of the wall 121. The backfill stone slag 9 covers the backwater surface of the wall 121 and the rib plate 128. The fourth protective body 10 is installed above the backfill stone slag 9 and is flush with the top surface of the cantilever plate 122.
[0090] Specifically, the fourth protective body 10 can be made of concrete or reinforced concrete with a thickness of 0.5m to 1.0m.
[0091] In this optional embodiment, after the sand retaining wall 1 is constructed, the back surface of the wall 121, the heel plate 127, and the newly added rib plate 128 will form an uneven back surface. If ordinary soil is directly backfilled, the fine-grained soil will hinder the free drainage of seepage water behind the wall, potentially causing water accumulation and generating hydrostatic pressure that is detrimental to the wall. Therefore, backfill stone chips 9 are set on the back surface of the wall 121. The porosity of the backfill stone chips 9 provides a channel for the rapid drainage of seepage water, effectively diverting groundwater or seepage water behind the wall 121, significantly reducing the hydrostatic pressure acting on the wall 121, and improving the structure's anti-sliding and anti-overturning stability. The backfill stone chips 9 cover and wrap the rib plate 128 and the back surface of the wall 121, providing uniform lateral earth pressure that can be adjusted with deformation, avoiding damage to the weak connection point of the rib plate 128 caused by local stress concentration, and protecting the back surface of the wall 121 and the rib plate 128 from direct contact with corrosive soil. Furthermore, the backfill stone slag 9 is often excavated material from engineering projects, and using local materials for backfilling realizes waste utilization and reduces the dual costs of purchasing soil and disposing of waste. The dense backfill stone slag 9, combined with the second protective body 125, further consolidates and strengthens the integrity and bearing capacity of the backwater side foundation.
[0092] If the top of the loose backfill stone slag 9 is exposed, it is easily eroded by rainwater, disturbed by humans, or damaged by animals, leading to stone slag loss and top collapse, affecting aesthetics and safety. Therefore, the fourth protective body 10 is set above the backfill stone slag 9 and is flush with the top surface of the cantilever slab 122. As a sturdy "cover", the fourth protective body 10 effectively prevents rainwater runoff from eroding and scouring the lower backfill stone slag 9, ensuring the long-term stability and effective operation of the drainage layer. The design of being flush with the top surface of the cantilever slab 122 allows maintenance personnel to pass safely and conveniently on the top of the sand retaining wall 1 and carry out maintenance work (such as inspecting the waterstop 11, expansion joint 100, etc.), greatly improving the maintainability of the project. The fourth protective body 10 covering the backfill stone slag 9 provides additional weight to the entire backwater side of the wall 121, enhancing anti-slip and anti-buoyancy stability. At the same time, it restrains the lateral deformation of the lower stone slag, improving the overall rigidity of the backwater side filling.
[0093] This invention provides a method for intercepting and guiding sand at the intake of a hydropower station using hydraulic dredging, based on the sand-intercepting and guiding system for hydraulic dredging at the intake of a hydropower station as described in the above embodiments, and includes the following steps: S1. Before the bedload sediment 6 carried by the main stream of the river 5 reaches the intake of the power plant 3, it is intercepted by the sediment trap 1. The sediment trap 1 is configured to be set at an angle to the direction of the main stream of the river 5, so as to reduce the cross-section of the main stream in the river 5 below the top of the sediment trap 1 and increase the bottom flow velocity of the sediment trap 1.
[0094] The main flow refers to the water flow within channel 5. The bottom flow of the sand-trapping embankment 1 refers to the water flow within channel 5 near the bottom of the sand-trapping embankment 1. Due to the compression of the flow cross-section by the sand-trapping embankment 1, the flow velocity at the bottom of the sand-trapping embankment 1 increases significantly, generating a strong sand-carrying force that propels the sediment along the embankment 1 towards the discharge channel, continuously guiding the sediment in front of the embankment.
[0095] When sediment is guided to the top of the sand-blocking embankment 1, the top cantilever slab 122 structure completely blocks it.
[0096] S2. The increased flow velocity of the underflow flows along the extension direction of the sand-blocking dam 1, generating a sand-carrying force pointing towards the discharge and flushing gate 4; under the combined action of the increased flow velocity of the underflow and the sand-carrying force, the intercepted bedload sediment 6 is pushed along the guide channel towards the discharge and flushing gate 4.
[0097] Under the continuous push of the water flow, the blocked sediment can only be discharged into the discharge channel and flood discharge and sand flushing gate along the preset inclined path, achieving zero-energy automatic removal.
[0098] S3. When the flood season arrives and the main flow of the river channel 5 increases, the overall velocity of the main flow in front of the sand-blocking sluice 1 further increases, and the sand-discharging efficiency of the sand-blocking and guiding system used for hydraulic dredging at the intake of the hydropower station is enhanced accordingly. The bedload sediment 6 that is guided to the vicinity of the top of the sand-blocking sluice 1 is blocked by the cantilever plate 122 at the top of the sand-blocking sluice 1 and falls back. Under the push of the increased main flow velocity, the bedload sediment 6 accelerates to move along the bottom flow direction of the river channel 5 and is discharged to the downstream side of the discharge and flushing gate 4 after passing through the discharge and flushing gate 4.
[0099] Among them, the main current on the front side of the sand-blocking dam 1 refers to the main current on the upstream side of the sand-blocking dam 1. The downstream side of the spillway and sand-flushing gate 4 refers to the side of the spillway and sand-flushing gate 4 away from the main current of the river channel 5, or the discharge direction of the main current through the spillway and sand-flushing gate 4.
[0100] Furthermore, as the flow velocity of the main stream in front of the sand-blocking dam 1 increases, the sand-carrying capacity of the main stream also increases accordingly. After encountering the sand-blocking dam, the mud and sand collide and are suspended, moving upward along the wall 121. They are blocked by the cantilever plate 122 and collide with it, rebounding downward and falling back down.
[0101] The sand-blocking and guiding method for hydraulic dredging at the intake of a hydropower station in this embodiment has the same beneficial effects as the sand-blocking and guiding system for hydraulic dredging at the intake of a hydropower station described above, and will not be repeated here.
[0102] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.
Claims
1. A sand-blocking and sand-guiding system for hydraulic dredging at the intake of a hydropower station, applied to the power station, the power station comprising a powerhouse (3) and a spillway and sand-flushing gate (4) arranged at intervals, characterized in that, The sand-blocking and sand-guiding system for hydraulic dredging at the intake of a hydropower station includes a sand-blocking sill (1) and a longitudinal guide wall (2). One end of the sand-blocking sill (1) is connected to a rocky bank slope (51), and the end of the sand-blocking sill (1) away from the rocky bank slope (51) is connected to one end of the longitudinal guide wall (2). The sand-blocking sill (1) is configured to be set at an angle to the mainstream direction of the river channel (5). The end of the longitudinal guide wall (2) away from the sand-blocking sill (1) is connected to the space between the power plant building (3) and the spillway and sand flushing gate (4). The water-facing surface of the sand-blocking sill (1) and the longitudinal guide wall (2) form a flow channel for guiding the displacement of sediment (6).
2. The sand-blocking and sand-guiding system for hydraulic dredging at the intake of a hydropower station according to claim 1, characterized in that, The sand-blocking embankment (1) is configured such that the angle between it and the main flow direction of the river channel (5) is between 30° and 45°.
3. The sand-blocking and sand-guiding system for hydraulic dredging at the intake of a hydropower station according to claim 1, characterized in that, The sand-blocking embankment (1) includes a waterstop (11) and a plurality of sand-blocking embankment bodies (12) spaced apart along its length. An expansion joint (100) is formed between two adjacent sand-blocking embankment bodies (12), and the waterstop (11) is fixedly installed in the expansion joint (100).
4. The sand-blocking and sand-guiding system for hydraulic dredging at the intake of a hydropower station according to claim 3, characterized in that, The main body (12) of the sand-blocking embankment includes a wall (121) and a cantilever slab (122). The wall (121) is fixed to the foundation (200), and the cantilever slab (122) is fixed to the top of the wall (121). The cantilever slab (122) extends toward the water-facing side of the wall (121). The thickness of the cantilever slab (122) gradually decreases from the end closest to the wall (121) to the end furthest from the wall (121).
5. The sand-blocking and sand-guiding system for hydraulic dredging at the intake of a hydropower station according to claim 3, characterized in that, It also includes a protective headband (7), which is located at the connection between the sand-blocking sill (1) and the longitudinal guide wall (2).
6. The sand-blocking and sand-guiding system for hydraulic dredging at the intake of a hydropower station according to claim 4 or 5, characterized in that, The thickness of the wall (121) gradually increases from the top to the bottom.
7. The sand-blocking and sand-guiding system for hydraulic dredging at the intake of a hydropower station according to claim 6, characterized in that, The main body (12) of the sand-blocking embankment also includes anchor bars (123), a part of which is fixedly inserted into the wall (121), and the other part of which is fixedly inserted into the foundation (200).
8. The sand-blocking and sand-guiding system for hydraulic dredging at the intake of a hydropower station according to claim 6, characterized in that, The main body (12) of the sand-blocking embankment also includes a first protective body (124) and a second protective body (125). The first protective body (124) is disposed on the water-facing side of the wall (121) and is used to connect with the bottom of the water-facing surface of the foundation (200) and the wall (121). The second protective body (125) is disposed on the backwater side of the wall (121), and the second protective body (125) is used to connect with the bottom of the backwater side of the foundation (200) and the wall (121).
9. The sand-blocking and sand-guiding system for hydraulic dredging at the intake of a hydropower station according to claim 4 or 5, characterized in that, The thickness of the top end of the wall (121) is the same as the thickness of the bottom end of the wall (121).
10. The sand-blocking and sand-guiding system for hydraulic dredging at the intake of a hydropower station according to claim 9, characterized in that, The main body (12) of the sand-blocking embankment also includes a toe plate (126) and a heel plate (127). The toe plate (126) is fixedly connected to the bottom of the water-facing side of the wall (121), and the heel plate (127) is fixedly connected to the bottom of the back side of the wall (121). The length of the wall toe slab (126) is greater than or equal to half the length of the cantilever slab (122).
11. The sand-blocking and sand-guiding system for hydraulic dredging at the intake of a hydropower station according to claim 10, characterized in that, The main body (12) of the sand-blocking embankment also includes a plurality of ribs (128), which are distributed at intervals along the length of the main body (12) of the sand-blocking embankment. The ribs (128) are fixedly installed at the connection between the wall (121) and the wall heel plate (127).
12. The sand-blocking and sand-guiding system for hydraulic dredging at the intake of a hydropower station according to claim 10, characterized in that, It also includes a third protective body (8), which is located on the water-facing side of the wall (121) and covers the foundation (200).
13. The sand-blocking and sand-guiding system for hydraulic dredging at the intake of a hydropower station according to claim 11, characterized in that, It also includes backfill stone (9) and a fourth protective body (10) disposed on the backwater side of the wall (121), the backfill stone (9) covering the backwater side of the wall (121) and the rib (128), and the fourth protective body (10) disposed above the backfill stone (9) and flush with the top surface of the cantilever slab (122).
14. A method for intercepting and guiding sand in hydraulic dredging at the intake of a hydropower station, based on the sand intercepting and guiding system for hydraulic dredging at the intake of a hydropower station as described in any one of claims 1 to 13, characterized in that, Includes the following steps: Before the bedload sediment (6) carried by the main stream of the river (5) reaches the intake of the power plant (3), it is intercepted by the sand-blocking sill (1). The sand-blocking sill (1) is configured to be set at an angle to the main stream direction of the river (5) to reduce the cross-section of the main stream in the river (5) below the top of the sand-blocking sill (1) and increase the bottom flow velocity of the sand-blocking sill (1). The increased flow velocity of the underflow flows along the extension direction of the sand-blocking sill (1), generating a sand-carrying force pointing towards the discharge and flushing gate (4); under the combined action of the increased flow velocity of the underflow and the sand-carrying force, the intercepted bedload sediment (6) is pushed along the guide channel towards the discharge and flushing gate (4). When the flood season arrives and the mainstream flow of the river (5) increases, the overall velocity of the mainstream flow in front of the sand-blocking sluice (1) further increases, and the sand discharge efficiency of the sand-blocking and guiding system used for hydraulic dredging of the hydropower station intake is enhanced accordingly. The bedload sediment (6) that is guided to the top of the sand-blocking sluice (1) is blocked by the top of the sand-blocking sluice (1) and falls back. Under the push of the increased mainstream flow velocity, the bedload sediment (6) accelerates to move along the bottom flow direction of the river (5) and is discharged to the downstream side of the discharge and flushing sluice (4) after passing through the discharge and flushing sluice (4).