Overhaul type gate dam stilling pool structure

Abstract

The invention discloses a gate dam stilling pool structure, particularly discloses a maintainable gate dam stilling pool structure, and belongs to the technical field of design and manufacturing of water conservancy and hydropower engineering structures. The invention provides the maintainable gate dam stilling pool structure which is convenient to maintain and can obviously reduce the maintenance cost of the stilling pool. The overhauled gate dam stilling pool structure comprises a concrete bottom plate, a water blocking and draining structure and an anti-scour energy dissipation structure, the water blocking and draining structure and the anti-scour energy dissipation structure which are sequentially arranged in the water flow direction are arranged on a riverbed of a mountain river channel through the concrete bottom plate, and the overhauled gate dam stilling pool structure further comprises a composite overhauling water blocking mechanism. In the overhauling process of the water retaining and draining structure and the anti-scour energy dissipation structure, water flow in the upstream river channel and the downstream river channel of the gate dam is cut off as required through the composite overhauling water retaining mechanism.

Description

Technical Field

[0001] This invention relates to a stilling basin structure for dams, and more particularly to a maintainable stilling basin structure for dams, belonging to the field of design and manufacturing technology for water conservancy and hydropower engineering structures. Background Technology

[0002] The main methods for energy dissipation and scour prevention in mountainous river dams are stilling basin bottom flow energy dissipation and rapid flow connection. For a common concrete dam with a water-retaining height of 20-50m, the water-retaining and flood-discharging energy dissipation structure typically includes a concrete gate chamber floor slab, gate piers, breast wall, working arc gate, upstream maintenance gate, downstream maintenance gate, stilling basin floor slab, sidewalls, and tail sill. The flood discharge gate uses an arc gate for water retention and is opened and closed by a hydraulic hoist. The upstream maintenance gate is opened and closed by a gantry crane on the gate top. For power stations with high downstream water levels during normal operation, considering the maintenance needs of the arc working gate and gate chamber, a downstream maintenance gate is installed at the end of the gate chamber, and an additional gantry crane is installed as the opening and closing device for the downstream maintenance gate. The downstream maintenance gate is an exposed planar sliding beam gate. The gate is operated by a bidirectional gantry crane located on the downstream gate top platform in conjunction with a corresponding hydraulic grab beam. A sloping section is set downstream of the gate chamber to connect to the stilling basin. The stilling basin is a reinforced concrete structure, consisting of a bottom slab, side walls, and tail sill.

[0003] The main problems with the existing hydraulic structures are as follows: 1) Energy dissipation structures of dams and sluices occupy an important position in the layout of power plants. A review of the design and operation of flood discharge energy dissipation structures at home and abroad reveals a high damage rate. Stilling basins often suffer varying degrees of damage, requiring inspection and repair. In power plants with high downstream water levels, repairs to the stilling basin can only be carried out by constructing temporary cofferdams downstream of the basin, which is costly, inconvenient, and results in poor conditions for stilling basin repair.

[0004] 2) During the maintenance of the stilling basin, water is pumped out after a temporary cofferdam is built downstream, which takes a long time. In addition, the airtightness of the temporary cofferdam is poor when the construction quality is not high, and water is prone to seepage, making it difficult to create dry construction conditions during the maintenance of the stilling basin. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a repairable gate dam stilling basin structure that is easy to maintain and can significantly reduce the maintenance cost of the stilling basin.

[0006] The technical solution adopted to solve the above-mentioned technical problems is: a maintainable dam stilling basin structure, including a concrete base slab, a water-retaining structure and an anti-scour and energy-dissipating structure. The water-retaining structure and the anti-scour and energy-dissipating structure are arranged sequentially along the water flow direction and are laid on the riverbed of the mountain river through the concrete base slab. The dam stilling basin structure also includes a composite maintenance water-retaining mechanism. During the maintenance of the water-retaining structure and the anti-scour and energy-dissipating structure, the water flow in the upstream and downstream river channels of the dam is cut off as needed by the composite maintenance water-retaining mechanism.

[0007] Furthermore, the concrete base slab includes a concrete gate chamber base slab and a concrete stilling basin base slab, with the elevation of the concrete gate chamber base slab on the upstream side being higher than that of the concrete stilling basin base slab on the downstream side; the water-retaining and spillway structures are arranged sequentially along the width of the mountain river channel on the middle and front sections of the concrete gate chamber base slab, while the scour prevention and energy dissipation structures are arranged on the concrete stilling basin base slab; and composite maintenance water-retaining mechanisms are respectively installed at the inlet of the water-retaining and spillway structures and at the outlet of the scour prevention and energy dissipation structures.

[0008] The preferred embodiment of the above scheme is that the water-retaining and spillway structure includes at least two sets of gate piers and at least one flood discharge working gate chamber. Each set of gate piers is arranged sequentially at a specified interval on the concrete gate chamber floor slab on the upstream side along the width of the mountain river channel. A flood discharge channel formed by two adjacent sets of gate piers is opened or closed through a flood discharge working gate chamber. The composite maintenance and water-retaining mechanism located on the upstream side is arranged on the flood discharge channel on the upstream side of each flood discharge working gate chamber.

[0009] Furthermore, four to six flood discharge channels are arranged sequentially along the width of the mountain river. The scour prevention and energy dissipation structure includes three stilling basin side walls extending along the river flow direction. The concrete stilling basin bottom slab is divided into two stilling basins extending along the water flow direction by the three stilling basin side walls. The outlet ends of the two to three adjacent flood discharge channels are respectively connected to one stilling basin. A composite maintenance water-blocking mechanism is installed at the outlet end of each stilling basin.

[0010] The preferred embodiment of the above scheme is that the composite maintenance and water-blocking mechanism includes at least an upstream emergency maintenance gate group and a downstream maintenance gate group. The upstream emergency maintenance gate group is arranged at the inlet end of the water-blocking and discharge structure, and the downstream maintenance gate group is arranged at the outlet end of the anti-scour and energy-dissipating structure.

[0011] Furthermore, the upstream emergency maintenance gate assembly includes two emergency maintenance gate leaves, four to six sets of emergency maintenance gate slots, and two mobile gate hoists. Each emergency maintenance gate slot is arranged on the gate pier at the upstream end of each flood discharge channel. The two emergency maintenance gate leaves are respectively connected by two mobile gate hoists to close the corresponding flood discharge channel in coordination with the corresponding emergency maintenance gate slots, so that the flood discharge working gate chamber to be repaired needs to be closed.

[0012] The preferred embodiment of the above scheme is that the downstream maintenance gate group includes two maintenance gate leaves, four sets of maintenance gate slots, and a mobile hoist. The outlet end of each stilling basin is divided into two drainage channels by an intermediate pier in cooperation with the side walls of the stilling basins on both sides. A set of maintenance gate slots is arranged on each drainage channel. The two maintenance gate leaves close the corresponding drainage channel of the stilling basin to be maintained by means of the mobile hoist in cooperation with the corresponding maintenance gate slot.

[0013] Furthermore, the composite maintenance water-blocking mechanism also includes a stilling pool drainage component, which is located at the end of the side wall of the middle stilling pool; the remaining water in the two stilling pools is drained through the stilling pool drainage component.

[0014] The preferred embodiment of the above scheme is that the stilling basin emptying component includes two sets of pump sets, a valve well is set on the side wall of the middle stilling basin, the inlet ends of the two sets of pump sets arranged in the valve well are respectively arranged in the two stilling basins, and the outlet ends of the two sets of pumps are connected to the downstream river channel from the end of the side wall of the stilling basin.

[0015] Furthermore, a sump is set up in the stilling basin near the end of the stilling basin wall. Each pump set includes two submersible pumps. The outlets of the two submersible pumps arranged in the same sump are connected to the downstream river channel through the shut-off valves arranged in the corresponding valve wells with the cooperation of the stilling basin wall.

[0016] The beneficial effects of this invention are as follows: The technical solution provided in this application is based on existing concrete base slabs, water-retaining structures, and scour-resistant energy-dissipating structures. It combines these structures with the structural characteristics of the water-retaining and scour-resistant energy-dissipating structures arranged sequentially along the water flow direction on the riverbed of a mountainous riverbed via a concrete base slab. By adding a composite maintenance water-retaining mechanism, the stilling basin structure of this application is constructed. During the maintenance of the water-retaining and scour-resistant energy-dissipating structures, the water flow in the upstream and downstream channels of the dam is cut off as needed by the composite maintenance water-retaining mechanism. This solves the technical problem in the prior art where a temporary cofferdam must be built for maintenance of the downstream stilling basin, followed by pumping out the water. With the above-mentioned technical solution of this application, when maintenance of the stilling basin is required, the upstream and downstream water flows can be directly cut off by the composite maintenance water-retaining mechanism for pumping out water, eliminating the need for a temporary cofferdam. This not only makes the maintenance of the stilling basin much more convenient but also significantly reduces the maintenance cost. Attached Figure Description

[0017] Figure 1 This is a plan view of a maintainable dam stilling basin structure according to the present invention; Figure 2 for Figure 1 Top view.

[0018] The following are marked in the diagram: 1. Concrete gate chamber bottom slab; 2. Concrete stilling basin bottom slab; 3. Gate pier; 4. Stilling basin side wall; 5. Flood discharge channel; 6. Stilling basin; 7. Emergency maintenance gate leaf; 8. Emergency maintenance gate slot; 9. Mobile gate hoist; 10. Maintenance gate leaf; 11. Maintenance gate slot; 12. Mobile hoist; 13. Intermediate pier; 14. Valve well; 15. Sump; 16. Submersible pump; 17. Gate valve. Detailed Implementation

[0019] like Figure 1 , Figure 2The diagram illustrates a repairable dam stilling basin structure provided by this invention, which offers convenient maintenance and significantly reduces the cost of stilling basin maintenance. The repairable dam stilling basin structure includes a concrete base slab, a water-retaining structure, and an erosion-resistant and energy-dissipating structure. The water-retaining and erosion-resistant structures, arranged sequentially along the water flow direction, are situated on the riverbed of a mountainous river via the concrete base slab. It also includes a composite repairable water-retaining mechanism. During maintenance of the water-retaining and erosion-resistant structures, the water flow in the upstream and downstream channels of the dam is interrupted as needed by the composite repairable water-retaining mechanism. The technical solution provided in this application is based on existing concrete base slabs, water-retaining structures, and scour-resistant energy-dissipating structures. It combines these structures with the structural characteristics of the water-retaining and scour-resistant energy-dissipating structures arranged sequentially along the water flow direction on the riverbed of a mountainous riverbed via a concrete base slab. By adding a composite maintenance water-retaining mechanism, the stilling basin structure of this application is constructed. During maintenance of the water-retaining and scour-resistant energy-dissipating structures, the water flow in the upstream and downstream channels of the dam is cut off as needed by the composite maintenance water-retaining mechanism. This solves the technical problem in the prior art where temporary cofferdams must be built and the stilling basin pumped out for maintenance when repairing the downstream side. With the above-mentioned technical solution of this application, when maintenance of the stilling basin is needed, the upstream and downstream water flow can be directly cut off by the composite maintenance water-retaining mechanism for pumping and drainage operations, completely eliminating the need for temporary cofferdams. This not only makes the maintenance of the stilling basin much more convenient but also significantly reduces the maintenance cost. Based on existing technology, the concrete base slab of this application includes a concrete gate chamber base slab 1 and a concrete stilling basin base slab 2. The elevation of the concrete gate chamber base slab 1 on the upstream side is higher than that of the concrete stilling basin base slab 2 on the downstream side. The water-retaining and spillway structures are arranged sequentially along the width of the mountain river channel on the middle and front sections of the concrete gate chamber base slab 1, and the scour prevention and energy dissipation structures are arranged on the concrete stilling basin base slab 2. Composite maintenance water-retaining mechanisms are respectively provided at the inlet of the water-retaining and spillway structures and the outlet of the scour prevention and energy dissipation structures. More specifically, the water-retaining and spillway structures include at least two sets of gate piers 3 and at least one flood discharge working gate chamber. Each set of gate piers 3 is arranged sequentially along the width of the mountain river channel on the concrete gate chamber base slab 1 on the upstream side at a specified interval. A flood discharge channel 5 formed by two adjacent sets of gate piers 3 is opened or closed through a flood discharge working gate chamber. The composite maintenance water-retaining mechanisms on the upstream side are respectively arranged on the flood discharge channels 5 on the upstream side of each flood discharge working gate chamber. There are four to six flood discharge channels 5 arranged sequentially along the width of the mountain river. The scour prevention and energy dissipation structure includes three stilling basin side walls 4 extending along the direction of river flow. The concrete stilling basin bottom slab 2 is divided into two stilling basins 6 extending along the direction of water flow by the three stilling basin side walls 4. The outlet ends of the two to three adjacent flood discharge channels 5 are respectively connected to one stilling basin 6. A composite maintenance water-blocking mechanism is set at the outlet end of each stilling basin 6.

[0020] Accordingly, as the main structural improvement of this application, in order to adapt to the existing dam system and minimize modifications to the existing structure, the composite maintenance and water-retaining mechanism of this application includes at least an upstream emergency maintenance gate group and a downstream maintenance gate group. The upstream emergency maintenance gate group is arranged at the inlet end of the water-retaining and spillway structure, and the downstream maintenance gate group is arranged at the outlet end of the anti-scour and energy-dissipating structure. Accordingly, the upstream emergency maintenance gate group includes two emergency maintenance gate leaves 7, four to six sets of emergency maintenance gate slots 8, and two mobile gate hoists 9. Each set of emergency maintenance gate slots 8 is arranged on the gate pier 3 at the upstream end of each flood discharge channel 5. The two emergency maintenance gate leaves 7 are respectively closed by the two mobile gate hoists 9, and the flood discharge working gate chamber to be repaired is closed in cooperation with the corresponding emergency maintenance gate slot 8. The downstream maintenance gate assembly includes two maintenance gate leaves 10, four maintenance gate slots 11, and a mobile hoist 12. The outlet end of each stilling basin 6 is divided into two drainage channels by an intermediate pier 13 in cooperation with the side walls 4 of the stilling basins on both sides. A maintenance gate slot 11 is arranged on each drainage channel. The two maintenance gate leaves 10 close the corresponding drainage channel of the stilling basin to be maintained by the mobile hoist 12 in cooperation with the corresponding maintenance gate slot.

[0021] Furthermore, to completely drain the water from the stilling basin for maintenance, the composite maintenance water-blocking mechanism described in this application also includes a stilling basin emptying component, which is located at the tail end of the middle stilling basin side wall 4; the remaining water in the two stilling basins 6 is drained through the stilling basin emptying component. In this case, the preferred method is that the stilling basin emptying component includes two sets of water pumps, and a valve well 14 is provided on the middle stilling basin side wall 4. The inlet ends of the two sets of water pumps arranged in the valve well 14 are respectively arranged in the two stilling basins 6, and the outlet ends of the two sets of water pumps are connected to the downstream river channel from the end of the stilling basin side wall 4. Specifically, a sump 15 is provided in the stilling basin 6 near the end of the stilling basin sidewall. Each pump set includes two submersible pumps 16. The outlets of the two submersible pumps 16 arranged in the same sump 15 are connected to the downstream river channel through the stop valves 17 arranged in the corresponding valve wells 14 with the cooperation of the stilling basin sidewall 4.

[0022] In summary, the technical solution provided in this application also has the following advantages: 1) For dams with high downstream water levels, convenient conditions are created for the maintenance of stilling basins. Stilling basins can be maintained quickly and at low cost according to maintenance requirements.

[0023] 2) After moving the downstream maintenance gate of the flood discharge gate to the tail of the stilling basin, the hydraulic model test showed that the water flow at each flow rate of the gate outlet can form a submerged hydraulic jump in the stilling basin. The head of the hydraulic jump is located near the end of the gate chamber. Compared with the traditional conventional scheme, the water depth in the stilling basin is slightly increased, the bottom velocity is slightly reduced, and the time-averaged pressure and pulsating pressure in the stilling basin do not change much, resulting in better energy dissipation effect.

[0024] The technical solution of this application will be further described below through specific embodiments: The technical problem to be solved by this application is to provide a dam water-retaining and flood discharge energy dissipation structure that can take into account both the maintenance of the working gate and the maintenance of the stilling basin, and has low construction cost and low operation and maintenance cost.

[0025] The technical solution adopted in this application to solve the technical problem is as follows: 1) The dam and gate system for water retention, discharge and energy dissipation consists of a concrete gate chamber (bottom slab, gate piers, breast wall), working arc gate, upstream emergency gate and emergency gate hoist, downstream maintenance gate and maintenance gate hoist, and stilling basin (bottom slab, side walls, tail sill). 2) The flood discharge gate uses an arc-shaped steel gate to block water and is opened and closed by a hydraulic hoist. The upstream maintenance gate is opened and closed by a gate top hoist.

[0026] 3) The downstream maintenance gate of the spillway is located at the tail of the stilling basin, creating conditions for maintenance of the gate chamber and the stilling basin. Due to the large width of the stilling basin, the downstream maintenance gate is arranged in a two-span configuration, with a downstream mid-gate pier between the two spans. The gate type is an exposed planar sliding beam gate. The gate slot adopts a type I gate slot, and each gate leaf is lifted by two lifting units.

[0027] 4) A sump is installed inside the stilling basin, and a valve well is installed inside the side wall of the stilling basin, close to the sump. Considering the large sediment content of the stilling basin and the small pumping head, a submersible sewage pump is used as the maintenance and pumping equipment for the stilling basin. The outlet pipe of the submersible sewage pump is led to the gate of the stilling basin for discharge.

[0028] 5) A sloping section is set downstream of the gate chamber to connect to the stilling basin. The stilling basin is a reinforced concrete structure, consisting of a bottom slab, side walls, and tail sill.

[0029] The main operating principle is: 1) Close the working arc gates according to the maintenance requirements of the dam's working arc gates and stilling basin.

[0030] 2) Close the upstream emergency gate under still water conditions.

[0031] 3) Close the downstream maintenance gate. The gate is operated by static water opening and closing. Before opening the gate, the top section of the gate leaf can be opened slightly to pressurize the water level. After the water level difference between the upstream and downstream is ≤1m, the second lifting unit is then lifted.

[0032] 4) Start the submersible pump in the valve well inside the side wall of the stilling basin to drain the water in the stilling basin.

[0033] 5) Conduct maintenance on the arc gate and stilling basin.

Claims

1. A maintainable dam stilling basin structure, comprising a concrete base slab, a water-retaining and spillway structure, and an erosion-resistant and energy-dissipating structure, wherein the water-retaining and spillway structure and the erosion-resistant and energy-dissipating structure are arranged sequentially along the water flow direction and are situated on the riverbed of a mountainous river via the concrete base slab, characterized in that: The dam stilling basin structure also includes a composite maintenance water-blocking mechanism. During the maintenance of the water-blocking and spillway structure and the scour prevention and energy dissipation structure, the water flow in the upstream and downstream channels of the dam is cut off as needed by the composite maintenance water-blocking mechanism.

2. The maintainable dam stilling basin structure according to claim 1, characterized in that: The concrete base plate includes a concrete gate chamber base plate (1) and a concrete stilling basin base plate (2). The elevation of the concrete gate chamber base plate (1) located on the upstream side is higher than that of the concrete stilling basin base plate (2) located on the downstream side. The water-blocking and discharge structure is arranged sequentially on the middle and front section of the concrete gate chamber base plate (1) along the width direction of the mountain river channel, and the scour prevention and energy dissipation structure is arranged on the concrete stilling basin base plate (2). A composite maintenance water-blocking mechanism is set at the inlet of the water-blocking and discharge structure and the outlet of the scour prevention and energy dissipation structure.

3. The maintainable dam stilling basin structure according to claim 2, characterized in that: The water-blocking and discharge structure includes at least two sets of gate piers (3) and at least one flood discharge working gate chamber. Each set of gate piers (3) is arranged in sequence along the width of the mountain river channel at a specified interval on the concrete gate chamber bottom plate (1) on the upstream side. A flood discharge channel (5) formed by two adjacent sets of gate piers (3) is opened or closed through a flood discharge working gate chamber. The composite maintenance water-blocking mechanism located on the upstream side is arranged on the flood discharge channel (5) on the upstream side of each flood discharge working gate chamber.

4. The maintainable dam stilling basin structure according to claim 3, characterized in that: There are four to six flood discharge channels (5) arranged sequentially along the width of the mountain river. The scour prevention and energy dissipation structure includes three stilling basin side walls (4) extending along the direction of the river flow. The concrete stilling basin bottom slab (2) is divided into two stilling basins (6) extending along the direction of the water flow by the three stilling basin side walls (4). The outlet ends of the two to three adjacent flood discharge channels (5) are respectively connected to one stilling basin (6). A composite maintenance water-blocking mechanism is set at the outlet end of each stilling basin (6).

5. The maintainable stilling basin structure of a dam according to claim 1, 2, 3 or 4, characterized in that: The composite maintenance and water-blocking mechanism includes at least an upstream emergency maintenance gate group and a downstream maintenance gate group. The upstream emergency maintenance gate group is arranged at the inlet end of the water-blocking and discharge structure, and the downstream maintenance gate group is arranged at the outlet end of the anti-scour and energy-dissipating structure.

6. The maintainable dam stilling basin structure according to claim 5, characterized in that: The upstream emergency maintenance gate assembly includes two emergency maintenance gate leaves (7), four to six sets of emergency maintenance gate slots (8), and two mobile gate hoists (9). Each set of emergency maintenance gate slots (8) is arranged on the gate pier (3) at the upstream end of each flood discharge channel (5). The two emergency maintenance gate leaves (7) are respectively connected by two mobile gate hoists (9) to close the corresponding flood discharge channel (5) in cooperation with the corresponding emergency maintenance gate slots (8) for the flood discharge working gate chamber that needs to be repaired.

7. The maintainable dam stilling basin structure according to claim 6, characterized in that: The downstream maintenance gate assembly includes two maintenance gate leaves (10), four maintenance gate slots (11), and a mobile hoist (12). The outlet end of each stilling basin (6) is divided into two drainage channels by an intermediate pier (13) in cooperation with the side walls (4) of the stilling basins on both sides. A maintenance gate slot (11) is arranged on each drainage channel. The two maintenance gate leaves (10) close the corresponding drainage channel of the stilling basin to be maintained by the mobile hoist (12) in cooperation with the corresponding maintenance gate slot.

8. The maintainable dam stilling basin structure according to claim 7, characterized in that: The composite maintenance water-blocking mechanism also includes a stilling pool draining component, which is located at the end of the middle stilling pool sidewall (4); the remaining water in the two stilling pools (6) is drained through the stilling pool draining component.

9. The maintainable dam stilling basin structure according to claim 8, characterized in that: The stilling basin emptying assembly includes two sets of pump sets. A valve well (14) is provided on the middle stilling basin side wall (4). The inlet ends of the two sets of pump sets arranged in the valve well (14) are respectively arranged in the two stilling basins (6). The outlet ends of the two sets of pumps are connected to the downstream river channel from the end of the stilling basin side wall (4).

10. The maintainable dam stilling basin structure according to claim 9, characterized in that: A sump (15) is also provided in the stilling basin (6) near the end of the stilling basin sidewall. Each pump set includes two submersible pumps (16). The outlets of the two submersible pumps (16) arranged in the same sump (15) are connected to the downstream river channel through the stop valves (17) arranged in the corresponding valve wells (14) with the cooperation of the stilling basin sidewall (4).

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