Drop weir and construction process thereof

Abstract

The invention discloses a drop weir and a construction process thereof, and relates to the technical field of water conservancy construction, the drop weir comprises a stepped flow divider, the stepped flow divider is provided with at least one step, and the upstream of the stepped flow divider is vertically arranged and is higher than the river bottom; the spiral grooves are fixedly formed in all the steps, and the axes of the spiral grooves are parallel to the length direction of the steps; the stepped flow guide plates are obliquely arranged between every two adjacent steps, one end of each stepped flow guide plate is fixed to the corresponding spiral groove, the other end of each stepped flow guide plate extends in the direction away from the corresponding spiral groove, and the multiple stepped flow guide plates are arranged in the length direction of the steps at intervals; the channel assembly is parallel to the stepped shunt body and is used for reducing interference of main water flow to fishes and providing a stable migration path; the drop weir has the effects of reducing water flow energy and ensuring the stability of the drop weir.

Description

Technical Field

[0001] This application relates to the field of water conservancy engineering, and in particular to a drop weir and its construction technology. Background Technology

[0002] In the field of water conservancy engineering, drop weirs are a common type of hydraulic structure, playing a vital role in river regulation and water resource allocation. With the continuous development of water conservancy, the application of drop weirs is becoming increasingly widespread. They not only regulate water levels and control water flow speed, but also improve the river's ecological environment, promoting economic development and ecological balance in surrounding areas. In urban landscape water system construction, drop weirs can create unique waterscape effects, enhancing the city's landscape quality and residents' quality of life.

[0003] Prior to this technical solution, there were various conventional methods for designing and constructing drop weirs. The most common approach was to use a solid structure, with the main body being a plain concrete gravity structure, the height and width determined by the main channel. The upstream section of the weir was designed vertically, while the downstream section used different inlet methods, such as stepped inlet. The surface layer was typically made of materials like stone slabs or mortar-laid landscape stones, depending on the design. The foundation was usually placed on a layer of crushed stone or pebble-soil mixture with a certain natural bearing capacity, requiring no foundation treatment. Simultaneously, a geotextile filter was laid under the drop weir and the downstream stilling basin to ensure stable infiltration. The stilling basin was designed with a reinforced concrete structure, its width and depth determined according to actual needs in the direction of water flow. Furthermore, stepping stones were often designed on the top of the weir to facilitate traffic on both banks.

[0004] However, existing drop weir designs have certain shortcomings. Conventional drop weir structures are unable to reduce the disturbance of the main water flow to fish, cannot provide fish with a stable migration route, and are not conducive to the survival and reproduction of fish in the river ecosystem. Summary of the Invention

[0005] To reduce water flow energy and ensure the stability of drop weirs, this application provides a drop weir and its construction process.

[0006] This application provides a drop weir and its construction technology, adopting the following technical solution: A type of drop weir, including A stepped flow divider is provided with at least one step, and the upstream of the stepped flow divider is set vertically and is higher than the riverbed; A spiral groove is fixedly disposed on each step of the ladder, and the axis of the spiral groove is parallel to the length direction of the step. A stepped guide plate is inclinedly disposed between two adjacent steps. One end of the stepped guide plate is fixed to the spiral groove, and the other end extends away from the spiral groove. Multiple stepped guide plates are spaced apart along the length of the steps. The fishway assembly is parallel to the stepped flow divider to reduce the disturbance of the main water flow to fish and provide a stable migration path.

[0007] By adopting the above technical solutions, the upstream of the stepped flow divider stands upright and is higher than the riverbed, which can initially block and divert the water flow; the spiral groove is fixed on the steps and its axis is parallel to the length of the steps, which can guide the water flow in a specific direction; the stepped guide plate is inclined between adjacent steps, with one end fixed to the spiral groove and the other end extending and multiple plates spaced apart along the length of the steps, which can further guide and disperse the water flow; the fishway component is parallel to the stepped flow divider, which can reduce the interference of the main water flow on fish and provide a stable migration path for fish.

[0008] Optionally, the fishway assembly includes: An independent channel is provided, which is arranged longitudinally along the stepped flow distribution and is connected to each step of the step. Fishway guide plates, wherein multiple fishway guide plates are provided, and the multiple fishway guide plates are horizontally arranged at intervals in the independent channel, forming a zigzag flow channel in the independent channel; Resting pools are spaced apart between the fishway guide plates, and each resting pool is connected to the fishway guide plate.

[0009] By adopting the above technical solution, the independent channel is set longitudinally along the stepped flow divider and connected to each step, providing fish with a path to enter the independent channel from the steps; multiple fishway guide plates are set horizontally at intervals in the independent channel to form a zigzag flow channel, which can slow down the water flow speed and reduce the impact of the water flow on the fish; resting pools are set at intervals between the fishway guide plates and connected to the fishway guide plates, which can provide resting places for migratory fish. In combination with the stepped flow divider, spiral groove, stepped guide plates and fishway components, the interference of the main water flow on the fish is further reduced, providing fish with a more stable migration path.

[0010] Optionally, the spacing between two adjacent stepped guide plates is 1 / 8 of the water flow width.

[0011] By adopting the above technical solution, the distance between two adjacent stepped guide plates is 1 / 8 of the water flow width, so that the water flow forms a laminar flow zone with a Reynolds number ≤ 500 between the guide plates. This can reduce the interference of the main water flow on fish, provide a stable migration path, and the reasonable spacing of the stepped guide plates can make the water flow form a uniform flow distribution zone, optimize the water flow pattern and reduce the local flow velocity, avoid impacting the migration of fish, and better ensure the stability of the fish migration path.

[0012] Optionally, the fishway guide plate is provided with a honeycomb cavity grid on the side near the water flow direction.

[0013] By adopting the above technical solution and utilizing the special structure of the honeycomb cavity grid, the water flow forms multi-layered turbulence and micro-vortices when passing through the fishway guide plate, which consumes the kinetic energy of the water flow and significantly reduces the overall flow velocity in the fishway, providing a more suitable migration environment for fish.

[0014] Optionally, the angle between the fishway guide plate and the axis of the independent channel is between 10° and 30°.

[0015] By adopting the above technical solution, within an angle range of 10°-30°, the fishway guide plate can form a suitable zigzag flow channel in the independent channel, which is more conducive to slowing down the water flow speed and providing a more stable migration path for fish.

[0016] Optionally, a fishway groove is provided at the position where the two adjacent steps connect to each other.

[0017] By adopting the above technical solutions, additional migration channels and habitats are provided for fish, further optimizing their migration environment.

[0018] Optionally, a construction technique based on a drop weir includes: Step 1: Determine the size, location, and construction materials of the stepped flow divider; Step two, foundation construction, involves excavating the foundation and binding the reinforcing steel at the bottom layer, installing and fixing the formwork, and then pouring concrete after the formwork is installed. Step 3 involves constructing the stepped flow distribution system, which requires determining the centerline and edge lines of the stepped flow distribution system, as well as the position and dimensions of each step. Step four involves excavating, treating, tying, installing formwork, and pouring concrete for the independent passageway. After the foundation construction is completed, the walls of the independent passageway are constructed. Once the walls are completed, the independent passageway is connected to each step of the staircase according to the design requirements to ensure that fish can smoothly enter the independent passageway from the steps. Step 5: During the construction of the independent channel wall, pre-embed the connectors for the fishway guide plates. Set up a honeycomb mesh on the side of the guide plate closest to the water flow direction to slow the water flow. Install the fabricated fishway guide plates into the independent channel using the pre-embedded components. Multiple fishway guide plates are horizontally spaced to form a zigzag flow channel. Simultaneously, control the angle between the fishway guide plates and the axis of the independent channel to be between 10° and 30°.

[0019] By adopting the above technical solutions, the relevant parameters and construction materials of the stepped flow divider are clarified, providing a foundation for subsequent construction. Earthwork excavation, rebar binding, formwork installation, and concrete pouring are carried out on the foundation to ensure the stability of the drop weir foundation. The centerline, edge lines, and step dimensions of the stepped flow divider are determined to ensure accurate construction. The foundation and walls of the independent channel are constructed and connected to the steps to ensure that fish can smoothly enter the independent channel from the steps. Fishway guide plate connectors are pre-embedded in the walls of the independent channel, and honeycomb cavity mesh is set to slow down the water flow. The fishway guide plates are installed to form a zigzag flow channel, providing a stable migration path for fish and reducing the interference of the main water flow on the fish.

[0020] Optionally, step three specifically includes: Reinforcing bar binding should be carried out in layers. First, bind the bottom layer of reinforcing bars, and then bind the top layer of reinforcing bars to ensure that the spacing, quantity and specifications of the reinforcing bars meet the requirements. Template installation: Install the stepped flow divider template, using standardized steel or wooden templates. The spiral groove is fabricated and installed on-site. After the formwork is installed, the steel bars are tied and the formwork is installed on each step according to the spiral shape. Then, concrete is poured to form the spiral groove. The axis of the spiral groove must be parallel to the length of the step. Concrete pouring should be carried out in a stepped, layered manner after the reinforcement binding and formwork installation are completed. Concrete pouring should be carried out in layers, and the thickness of each layer should not exceed 300mm.

[0021] By adopting the above technical solutions, layered rebar tying ensures that the spacing, quantity, and specifications of the rebars meet the requirements, guaranteeing the structural strength and stability of the stepped flow divider. Using standardized steel or wooden formwork to install the stepped flow divider formwork ensures the shape and dimensional accuracy of the formwork. On-site fabrication and rebar tying, formwork installation, and concrete pouring on each step in a spiral shape to form a spiral groove, with the axis of the spiral groove parallel to the length of the step, accurately achieves the setting of the spiral groove. Layered concrete pouring with each layer not exceeding 300mm in thickness ensures the quality of concrete pouring and results in good formation of the stepped flow divider.

[0022] In summary, the embodiments of the present invention provide a drop weir and its construction process, including at least one of the following beneficial technical effects: The stepped flow divider is self-supporting upstream and higher than the riverbed, which can initially block and divert the water flow; the spiral groove is fixed on the steps and its axis is parallel to the length of the steps, which can guide the water flow in a specific direction; the stepped guide plate is inclined between adjacent steps, with one end fixed to the spiral groove and the other end extending and multiple plates spaced along the length of the steps, which can further guide and disperse the water flow; the fishway component is parallel to the stepped flow divider, which can reduce the interference of the main water flow on fish and provide a stable migration path for fish.

[0023] 2. By utilizing the special structure of the honeycomb cavity grid, more turbulence and eddies are generated when the water flows through the fishway guide plate, reducing the overall flow velocity and providing a more suitable migration environment for fish. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a drop weir provided in an embodiment of the present invention; Figure 2 A cross-sectional view of a drop weir provided in an embodiment of the present invention; Figure 3 This is a partial enlarged view of a drop weir provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a fishway component in a drop weir provided in an embodiment of the present invention; Figure 5 This is a structural diagram of a fish passage guide plate in a drop weir provided in an embodiment of the present invention.

[0025] Explanation of the markings in the image: 1. Stepped flow distribution; 11. Stepped; 12. Riverbed; 13. Spiral groove; 14. Stepped guide plate; 21. Independent channel; 22. Fishway guide plate; 24. Honeycomb cavity grid; 31. Fishway groove. Detailed Implementation

[0026] The following is in conjunction with the appendix Figure 1-5 This application will be described in further detail.

[0027] Combination Figure 1 , Figure 2 and Figure 3This application discloses a drop weir and its construction process, including: the drop weir provided in this application includes a stepped flow divider 1, a spiral groove 13, a stepped guide plate 14, and a fishway assembly. The stepped flow divider 1 divides the main channel through a stepped structure 11 perpendicular to the water flow direction. The spiral groove 13 is embedded in the surface of each step 11 to form a water flow vortex zone. The stepped guide plate 14 connects adjacent steps 11 in an inclined posture to form a guiding gap. The fishway assembly extends longitudinally along the stepped flow divider 1 and communicates with each step 11. This structure effectively disperses hydraulic potential energy through the synergistic effect of multi-stage flow division and spiral turbulence. The zigzag flow channel of the fishway assembly provides a low-energy migration path for fish.

[0028] Specifically, the stepped flow divider 1 comprises a three-tiered, 11-step concrete base. The upstream section uses a vertical retaining wall structure 121.0m above the riverbed, with each step 11 having a horizontal projection dimension of 2.5m × 1.2m. A φ16mm tensile steel mesh is pre-embedded at the bottom of the base, and U-shaped grooves (depth ≥ 5cm) are pre-reserved on the surface for anchoring the spiral grooves 13. The steps 11 are connected by sloping transition sections with a slope controlled within 1:3. Alternative solutions include using modularly assembled precast concrete units, or laying a layer of natural pebbles on the surface of the steps 11 to enhance permeability.

[0029] Combination Figure 1 , Figure 2 and Figure 3 The spiral groove 13 is composed of a double spiral structure with its central axis parallel to the length of the step 11, and its inner wall has a 45° chamfer to reduce water flow impact. Its main body is a C30 grade cast-in-place concrete component, with internally embedded φ8mm stainless steel reinforcing ribs to prevent deformation. The spacing between adjacent grooves is controlled at 0.8m, and the groove depth is 15-25cm, decreasing in a gradient with the height of the step 11. Alternative solutions include using a spiral pipe molded from prestressed FRP composite material, or installing a removable maintenance cover at the bottom of the groove.

[0030] The stepped guide plate 14 is made of triangular cross-section carbon steel, 6mm thick, and hot-dip galvanized for corrosion protection. The front end of the plate is welded and fixed to the groove of the spiral groove 13, and the rear end is movably connected to the next step 11 via a hinged support. The lateral spacing between adjacent guide plates is precisely controlled to 1 / 8 of the width of the water flow in the corresponding cross-section. The plate surface is stamped with diamond-shaped raised patterns to enhance flow stability. Alternative solutions include using polycarbonate composite panels or adding a pressure sensor to the back of the plate to monitor the water flow impact force.

[0031] Combination Figure 4 and Figure 5The fishway component comprises a longitudinally continuous reinforced concrete box culvert with a top width of 0.8m and a height adjusted to maintain a 1:10 inlet angle according to the river slope. Seven sets of fishway guide plates 22 are installed inside the box culvert, each forming a 20° angle with the culvert axis, and the plate surface is covered with a 5cm diameter hexagonal honeycomb grid. Stainless steel support frames are pre-embedded beneath the guide plates and connected to the culvert wall via expansion bolts. Elliptical resting pools are located between adjacent guide plates, and the pools are lined with biomimetic fish nest bricks. Alternative options include using a prefabricated aluminum alloy frame structure or installing a temperature control system at the bottom of the resting pools to maintain a suitable water temperature.

[0032] The implementation principle of this embodiment is as follows: the stepped flow divider 1 forms a gradual pressure reduction through the height difference of the steps 11; the spiral groove 13 uses the principle of fluid dynamics to convert kinetic energy into rotational potential energy; and the array of stepped guide plates 14 guides the water flow to diffuse to both sides. The combined effect of these three elements reduces the flow velocity in the main channel. The fishway component extends the migration distance through a zigzag path, the honeycomb grid structure reduces the local flow velocity, and the periodic setting of the resting pool reduces the energy consumption of fish. Overall, a new type of cascading structure that combines hydraulic efficiency and ecological friendliness is formed.

[0033] The stepped guide vane 14 features an adjustable tilt angle design, and its support structure consists of a two-section telescopic rod. The outer tube of the telescopic rod is fixed to the lower step 11, and the inner tube adjusts the tilt angle of the guide vane via locking bolts, with the adjustment range limited to 5°-25°. A water flow pressure detector is installed on the back of the guide vane; when the detected water flow pressure exceeds a set threshold, it triggers a hydraulic cylinder to automatically adjust the tilt angle.

[0034] The implementation principle of this embodiment is as follows: the adjustable guide plate can dynamically optimize the guide angle according to real-time hydrological conditions. During the flood season, the angle of the water-facing surface is increased to enhance the diversion capacity, and during the dry season, the standard angle is restored to maintain the ecological flow. This adaptive mechanism makes the drop weir more environmentally adaptable.

[0035] The construction process based on a drop weir provided in this application includes the following steps: S1. Determine the dimensions, location, and construction materials of the stepped flow divider 1. In this step, the dimensions of the stepped flow divider 1 need to be accurately measured and calculated based on the actual conditions of the river channel and design requirements, and its specific location in the river channel needs to be determined. The selection of construction materials should take into account factors such as strength, durability, and economy. Reinforced concrete of grade C30 or higher is usually selected to balance structural strength and durability.

[0036] S2, Foundation Construction: This involves excavating the foundation, reinforcing steel at the bottom layer, installing and securing the formwork, and then pouring concrete. Excavation must be carried out according to design requirements to ensure the foundation's flatness and bearing capacity. Specifically, excavation should be performed at the designed slope ratio (e.g., 1:0.5). After excavation, the foundation should be compacted (compaction degree ≥95%) to ensure the flatness and bearing capacity meet design requirements. Reinforcing steel binding must ensure the spacing, quantity, and specifications of the reinforcing bars meet requirements, and the formwork must be securely installed to guarantee the quality of the concrete pouring.

[0037] S3 involves the construction of the stepped flow divider 1, which requires determining the centerline and edge lines of the stepped flow divider 1, as well as the position and dimensions of each step 11. Specifically, this includes rebar tying, which must be done in layers, first tying the bottom layer of rebar, then the top layer, ensuring the spacing, quantity, and specifications of the rebar meet requirements; formwork installation, installing the formwork for the stepped flow divider 1, using standardized steel or wooden formwork; the spiral groove 13 is fabricated on-site using a cast-in-place method. After the stepped flow divider formwork is installed, a spiral rebar skeleton is laid along the length of each step 11 at the preset position (0.3m from the edge of the step) according to the design coordinates, and the spiral formwork is fixed with positioning bolts (the inner wall of the formwork is flush with the surface of the step), then poured synchronously with the step concrete to form the spiral groove 13; the axis of the spiral groove 13 must be parallel to the length of the step 11; and concrete pouring, after the rebar tying and formwork installation are completed, the concrete for the stepped flow divider 1 is poured. Concrete pouring adopts a layered continuous pouring method, and the thickness of each layer should not exceed 300mm. Vibration is carried out using an immersion vibrator (vibration spacing ≤ 50cm) to ensure concrete compaction.

[0038] S4 involves foundation excavation, treatment, rebar tying, formwork installation, and concrete pouring for the independent passage 21. After foundation construction, the walls of the independent passage 21 are constructed. Once the walls are completed, the independent passage 21 is connected to each step 11 according to design requirements, ensuring that fish can smoothly enter the independent passage 21 from the steps 11. Specifically, the independent passage 21 is connected to each step 11 through pre-drilled holes (diameter ≥ 20cm), with rounded edges (radius ≥ 5cm) to ensure fish can easily enter the independent passage 21. In this step, the construction quality of the independent passage 21 must be guaranteed to ensure smooth connection with the stepped flow divider 1.

[0039] S5. During the construction of the independent channel 21 wall, connectors for the fishway guide plates 22 are pre-embedded. A honeycomb mesh 24 is installed on the side of the fishway guide plate 22 closest to the water flow direction to slow the water flow. The fabricated fishway guide plates 22 are then installed within the independent channel 21 using the pre-embedded components. Multiple fishway guide plates 22 are horizontally spaced to form a zigzag flow channel. Simultaneously, the angle between the fishway guide plates 22 and the axis of the independent channel 21 must be controlled between 10° and 30°. The key to this step lies in the installation and angle control of the fishway guide plates 22 to ensure the formation of the zigzag flow channel and the effect of regulating the water flow speed. Multiple fishway guide plates 22 are horizontally arranged at intervals of 0.5-1.0m, with an elliptical resting pool (1.2m major axis, 0.8m minor axis) reserved between adjacent guide plates. The bottom of the resting pool is flush with the bottom surface of the independent channel 21.

[0040] The implementation principle of this embodiment is as follows: This construction process follows a reasonable sequence for constructing the drop weir, with clear operational requirements and quality standards for each step, from foundation construction to the installation of various components. Precise construction ensures the structural stability and functionality of the drop weir. Especially during the construction of the fishway components, strict control of various parameters provides a favorable migratory environment for fish. Compared with existing technologies, this construction process places greater emphasis on the survival needs of fish, thus improving the ecological benefits of the drop weir.

[0041] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A drop weir, characterized in that, include: A stepped flow divider (1) is provided with at least one step (11), and the upstream of the stepped flow divider (1) is set vertically and is higher than the riverbed (12). A spiral groove (13) is fixedly disposed on each step (11), and the axis of the spiral groove (13) is parallel to the length direction of the step (11); A stepped guide plate (14) is inclinedly disposed between two adjacent steps (11). One end of the stepped guide plate (14) is fixed to the spiral groove (13), and the other end extends away from the spiral groove (13). Multiple stepped guide plates (14) are spaced apart along the length direction of the steps (11). The fishway assembly is parallel to the stepped flow divider (1) to reduce the disturbance of the main water flow to fish and provide a stable migration path.

2. A drop weir according to claim 1, characterized in that, The fishway assembly includes: Independent channel (21), the independent channel (21) is arranged longitudinally along the stepped flow divider (1), and the independent channel (21) is connected to each step (11); Fishway guide plate (22), multiple fishway guide plates (22) are provided, and multiple fishway guide plates (22) are horizontally arranged at intervals in the independent channel (21), and multiple fishway guide plates (22) form a zigzag flow channel in the independent channel (21); Resting pools are spaced apart between the fishway guide plates (22), and each resting pool is connected to the fishway guide plate (22).

3. A drop weir according to claim 1, characterized in that, The spacing between two adjacent stepped guide plates (14) is 1 / 8 of the water flow width.

4. A drop weir according to claim 2, characterized in that, The fishway guide plate (22) has a honeycomb cavity grid (24) on the side near the water flow direction.

5. A drop weir according to claim 2, characterized in that, The angle between the fishway guide plate (22) and the axis of the independent channel (21) is between 10° and 30°.

6. A drop weir according to claim 1, characterized in that, Fishway grooves (31) are provided at the positions where two adjacent steps (11) are connected to each other.

7. A construction process based on a drop weir, wherein the drop weir is based on any one of claims 1-6, characterized in that: Step 1: Determine the size, location, and construction materials of the stepped flow divider (1); Step two, foundation construction, involves excavating the foundation and binding the reinforcing steel at the bottom layer, installing and fixing the formwork, and then pouring concrete after the formwork is installed. Step 3: Construction of the stepped flow divider (1), which requires determining the center line and edge line of the stepped flow divider (1), as well as the position and size of each step (11); Step 4: Excavate, treat, tie the reinforcing bars, install the formwork and pour the concrete for the independent passage (21). After the foundation construction is completed, construct the wall of the independent passage (21). After the wall of the independent passage (21) is completed, connect the independent passage (21) with each step (11) according to the design requirements to ensure that the fish can smoothly enter the independent passage (21) from the step (11). Step 5: During the construction of the wall of the independent channel (21), the connector of the fish passage guide plate (22) is pre-embedded. A honeycomb cavity grid (24) is set on the side of the guide plate close to the water flow direction to slow down the water flow speed. The fish passage guide plate (22) is installed in the independent channel (21) through the pre-embedded parts. Multiple fish passage guide plates (22) are set horizontally at intervals to form a zigzag flow channel. At the same time, the angle between the fish passage guide plate (22) and the axis of the independent channel (21) should be controlled between 10° and 30°.

8. The construction process of the drop weir according to claim 7, characterized in that: Step three specifically includes: Reinforcing bar binding should be carried out in layers. First, bind the bottom layer of reinforcing bars, and then bind the top layer of reinforcing bars to ensure that the spacing, quantity and specifications of the reinforcing bars meet the requirements. Template installation: Install the template for the stepped flow divider (1). The template shall be a standard steel template or a wooden template. The spiral groove (13) is made and installed on site. After the template is installed, the steel bars are tied and the template is installed on each step (11) according to the spiral shape. Then, concrete is poured to form the spiral groove (13). The axis of the spiral groove (13) should be parallel to the length direction of the step (11). After the reinforcement binding and formwork installation are completed, concrete pouring is carried out in a stepped distribution (1). Concrete pouring should be carried out in layers, and the thickness of each layer should not exceed 300mm.

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