An air-cushioned sedimentation tank structure

Abstract

The present invention belongs to the field of the structure of a pneumatic sedimentation tank in water conservancy and hydropower projects. The technical solution is as follows: A pneumatic sedimentation tank structure includes a working section of the sedimentation tank body and a downstream connection section arranged between the upstream pressurized water conveyance channel and the downstream pressurized water conveyance channel; the working section of the sedimentation tank body is a concrete pipe gallery, and the bottom is a sand flushing gallery; the starting point of the sand flushing gallery is connected to the upstream pressurized water conveyance channel, and the end is connected to an external sand discharge pipe; the upstream of the downstream connection section is connected to the sand flushing gallery, and the downstream is connected to the downstream pressurized water conveyance channel; an air charging and discharging pipe is arranged in the working section of the sedimentation tank body, and the pipe orifice of the air charging and discharging pipe is above the highest operating water level of the sedimentation tank. It effectively solves the influence of the change of the reservoir water level on the sedimentation tank, thereby reducing the height of the tank body structure and saving the project cost.

Description

Technical Field

[0001] The present invention relates to the field of sedimentation tank structures in water conservancy and hydropower projects, and particularly to an air-cushioned sedimentation tank structure for a hydropower station. Background Art

[0002] The setting conditions of a sedimentation tank in a hydropower station mainly depend on the corresponding relationship between the sediment content passing through the turbine, the coarse sediment content passing through the turbine, and the rated head of the water turbine. For a run-of-river power station, due to limited reservoir capacity and poor sedimentation effect in the reservoir, a sedimentation tank needs to be set up separately. The conventional layout forms of sedimentation tanks are divided into two types: ground and in-tunnel (underground), and usually both are unpressurized types. In addition to meeting the requirement of sedimentation rate, the conventional sedimentation tank is also affected by the variation range of the reservoir water level, that is, the lowest reservoir water level should meet the sedimentation rate requirement, and the highest reservoir water level determines the structural height of the sedimentation tank. For a sedimentation tank with a large variation range of reservoir water level, due to the unpressurized type, the sedimentation tank needs to increase the height of the tank body additionally to meet the water level variation. Abroad, some adopt the layout form of a pressurized full-flow sedimentation tank in the tunnel, and reduce the height of the sedimentation tank by means of pressurized full-flow in the tunnel, so as to save engineering costs. However, for the pressurized flow in the tunnel, the flow pattern is not as good as the unpressurized flow, and it is not easy to ensure the sedimentation rate.

[0003] At present, there is no accurate calculation method for the design of the body shape structure of the sedimentation tank. All the above three types of sedimentation tank forms need to test the sedimentation effect through a hydraulic model test and adjust and optimize the sedimentation tank structure. On the one hand, the hydraulic model test is an important basis for correcting the structural design; on the other hand, there are deviations in the hydraulic model test. One model can only correspond to one flow pattern, and the test results can only be finally verified after the project is put into operation, and it is very difficult to take engineering measures to correct the deviation. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides an air-cushioned sedimentation tank structure, which effectively solves the influence of the sedimentation tank on the change of the reservoir water level, thereby reducing the height of the tank body structure and saving engineering costs.

[0005] The technical solution of the present invention is as follows: An air-cushioned sedimentation tank structure includes a sedimentation tank body working section and a downstream connection section arranged between an upstream pressurized water conveyance tunnel and a downstream pressurized water conveyance tunnel; the sedimentation tank body working section is a concrete pipe gallery, and the bottom is a scour gallery; the starting point of the scour gallery is connected to the upstream pressurized water conveyance tunnel, and the end is connected to an external sand discharge pipe; the upstream of the downstream connection section is connected to the scour gallery, and the downstream is connected to the downstream pressurized water conveyance tunnel; an air charging and discharging pipe is arranged in the sedimentation tank body working section, and the pipe orifice of the air charging and discharging pipe is above the highest operating water level of the sedimentation tank.

[0006] Based on the above technical features: the sedimentation tank body working section includes an upper tank body, a tank wall, and a scour gallery at the bottom; the tank wall is located on both lower sides of the upper tank body.

[0007] Based on the above technical features: When the cross-sectional dimension of the sand flushing corridor meets the sand flushing flow rate, the flow velocity is greater than the sand incipient motion velocity.

[0008] Based on the above technical features: The trough wall forms a trapezoidal cross-section that is larger at the top and smaller at the bottom.

[0009] Based on the above technical features: The inclination angle of the trough wall is greater than the underwater static friction angle of the sand grains.

[0010] Based on the above technical features: The bottom elevation of the downstream connection section is higher than the top elevation of the sand flushing corridor.

[0011] Based on the above technical features: A sealing material is provided on the upper pool body.

[0012] Based on the above technical features: The sealing material is provided inside or on the surface of the structure of the upper pool body, and the bottom of the sealing material is located below the lowest operating water level of the sedimentation tank.

[0013] Based on the above technical features: The sand flushing corridor is a longitudinal ramp with a starting point higher than the end point.

[0014] The air-cushioned sedimentation tank structure of the present invention can adjust the flow regime in the tank by inflating or exhausting air through the air charging and discharging pipe, thereby changing the air pressure, making the adjustment of the sedimentation tank dynamically controllable and avoiding the risk brought by the deviation of the model test, and achieving the best sedimentation effect. In addition, the present invention can select in-cave layout or ground layout according to the engineering geological and topographical conditions. When the surrounding rock conditions of the cavern are good, the in-cave layout can make full use of the bearing effect of the surrounding rock, effectively reduce the structural thickness, and greatly save investment.

[0015] The advantages of the present invention are that it gets rid of the influence of the reservoir water level fluctuation on the sedimentation tank structure, can effectively reduce the height of the sedimentation tank, and corrects the deviation of the hydraulic model test. By adopting the in-cave sedimentation tank, the surrounding rock can be fully utilized to bear the water pressure, reducing the structural thickness of the sedimentation tank. The water depth can be adjusted at any time by using the air-cushion method, thereby adjusting the cross-sectional area of the flow, correcting the deviation of the hydraulic model test, and achieving the best sedimentation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a top view structure diagram of an air-cushioned sedimentation tank structure of the present invention, and the arrow direction in the figure is the water flow direction.

[0017] Figure 2 It is an elevation structure diagram of an air-cushioned sedimentation tank structure of the present invention.

[0018] Figure 3 It is a side view structure diagram of an air-cushioned sedimentation tank structure of the present invention, and the arrow direction in the figure is the water flow direction.

[0019] Description of Component Labels:

[0020] 1 Working section of the sedimentation tank body

[0021] 2 Downstream connection section

[0022] 3 Scouring gallery

[0023] 4 Groove wall

[0024] 5 Upper pool body

[0025] 6 Sealing material

[0026] 7 Upstream pressure intake channel

[0027] 8 Downstream pressure intake channel

[0028] 9 Sand discharge pipe

[0029] 10 Air charging and exhaust pipe

[0030] A Minimum operating water level

[0031] B Maximum operating water level Detailed implementation manners

[0032] The following further describes in detail the detailed implementation manners of the present invention with reference to the accompanying drawings. These implementation manners are only used to illustrate the present invention and are not intended to limit the present invention.

[0033] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0034] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] In addition, in the description of the present invention, unless otherwise stated, the meaning of "a plurality of" is two or more.

[0036] Such as Figure 1 、Figure 2 , Figure 3 As shown in Figure 3 , the present invention provides an air-cushioned sedimentation tank structure, which includes a sedimentation tank body working section 1 and a downstream connection section 2 arranged between an upstream pressurized diversion channel 7 and a downstream pressurized diversion channel 8, forming a closed structure. The sedimentation tank body working section 1 is composed of an upper tank body 5, a middle tank wall 4, and a bottom scour gallery 3. The upper tank body 5 can adopt a gate-opening type reinforced concrete structure, and the cross-section of the scour gallery 3 can adopt a rectangle. The starting point of the scour gallery 3 is connected to the upstream pressurized diversion channel 7, and the end is connected to an external sand discharge pipe 9. The longitudinal slope of the scour gallery 3 from the starting point downward is 2%. The tank wall 4 has a trapezoidal cross-section, and the inclination angle of the tank wall 4 can be 45°. It is advisable that the inclination angle of the tank wall is greater than the underwater static friction angle of the sand grains. The sealing material 6 adopts a steel plate, which is arranged in the concrete structure of the upper tank body 5, and the steel plate extends below the lowest operating water level A of the sedimentation tank to form an airtight structure. The sedimentation tank body working section 1 can be arranged in a tunnel or on the ground according to the engineering geological and topographical conditions. When the surrounding rock conditions are good, arranging it in a tunnel can make full use of the bearing effect of the surrounding rock, effectively reduce the structural thickness, and greatly save investment.

[0037] An air charging and discharging pipe 10 is arranged in the sedimentation tank body working section 1, and the pipe orifice of the air charging and discharging pipe 10 is above the highest operating water level B of the sedimentation tank. The air pressure in the sedimentation tank can be changed by inflating or exhausting air through the air charging and discharging pipe 10, so as to adjust the flow regime in the tank. When the air pressure in the tank decreases, the water level in the tank rises and the flow velocity decreases. On the contrary, when the air pressure increases, the water level in the tank drops and the flow velocity increases.

[0038] The elevation of the bottom plate of the downstream connection section 2 is higher than the elevation of the top of the scour gallery 3, which can prevent the sediment in the scour gallery 3 from turning into the downstream connection section 2. The downstream connection section 2 is connected to the downstream pressurized diversion channel 8, that is, the downstream connection section 2 is a transition section between the sedimentation tank body working section 1 and the downstream pressurized diversion channel 8. The end of the scour gallery 3 is connected to the sand discharge pipe 9. The sand discharge pipe 9 and the air charging and discharging pipe 10 can both be arranged by using the previous construction adit, which can reduce the excavation and support work volume.

[0039] The present invention adopts a closed air-cushion structure, which effectively reduces the structural height of the sedimentation tank, and can adjust the water depth in the tank, change the flow velocity and flow regime by changing the air pressure, so as to achieve the best sedimentation tank effect. Figures 1 to 3 The outer contour shape of the sedimentation tank body working section 1 shown in Figures 1 to 3 is only a schematic illustration.

[0040] The conventional sedimentation basin is significantly affected by the variation range of the reservoir water level, and the highest reservoir water level determines the structural height of the sedimentation basin. Some foreign projects adopt the method of full-flow under pressure in the tunnel to reduce the height of the sedimentation basin, but the full-flow regime is poor and the sedimentation effect is significantly reduced. At present, there is no precise calculation method for the sedimentation basin. Generally, hydraulic model tests are used to preliminarily judge the sedimentation effect and determine the final structure. No matter which method is adopted, the flow regime corresponding to the sedimentation basin structure is often fixed, that is, after the actual operation, the sedimentation basin structure is determined and the water flow regime is also fixed and cannot be changed. It is very difficult to correct the deviation of the model test by other means.

[0041] Compared with the existing conventional sedimentation basin structure, the present invention can not only get rid of the limitation of the variation range of the reservoir water level, but also dynamically adjust the flow regime in the basin by changing the air pressure, making the regulation of the sedimentation basin dynamically controllable and avoiding the risk brought by the deviation of the model test, so as to achieve the best sedimentation effect.

[0042] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and replacements can be made, and these improvements and replacements should also be regarded as the protection scope of the present invention.

Claims

1. An air-cushioned sedimentation tank structure, characterized in that: It includes a sedimentation tank body working section (1) and a downstream connection section (2) arranged between an upstream pressurized water conveyance channel (7) and a downstream pressurized water conveyance channel (8); the bottom of the sedimentation tank body working section (1) is a sand flushing corridor (3); the starting point of the sand flushing corridor (3) is connected to the upstream pressurized water conveyance channel (7), and the end is connected to an external sand discharge pipe (9); the upstream of the downstream connection section (2) is connected to the sand flushing corridor (3), and the downstream is connected to the downstream pressurized water conveyance channel (8); an air charging and discharging pipe (10) is arranged in the sedimentation tank body working section (1), and the pipe orifice of the air charging and discharging pipe (10) is above the highest operating water level (B) of the sedimentation tank. The air pressure in the sedimentation tank can be changed by charging or discharging air into the air charging and discharging pipe (10), so as to adjust the flow pattern in the tank; The sedimentation tank body working section (1) includes an upper tank body (5), a middle tank wall (4) and the sand flushing corridor (3) at the bottom; the tank wall (4) is located on both lower sides of the upper tank body (5); The tank wall (4) forms a trapezoidal cross-section that is larger at the top and smaller at the bottom; The inclination angle of the tank wall (4) is greater than the underwater static friction angle of the sand grains, and the inclination angle of the tank wall (4) is 45°; The upper tank body (5) is provided with a sealing material (6); The sealing material (6) is arranged inside or on the surface of the structure of the upper tank body (5), and the bottom of the sealing material (6) is below the lowest operating water level (A) of the sedimentation tank; The air-cushioned sedimentation tank structure adopts a closed air-cushion structure, which effectively reduces the structural height of the sedimentation tank, and can adjust the water depth in the tank, change the flow velocity and flow pattern by changing the air pressure, so as to achieve the best sedimentation tank effect.

2. An air-cushioned sedimentation tank structure according to claim 1, characterized in that: The cross-sectional dimension of the sand flushing corridor (3) satisfies that the flow velocity is greater than the sand starting velocity under the sand flushing flow rate.

3. An air-cushioned sedimentation tank structure according to claim 1, characterized in that, The bottom elevation of the downstream connection section (2) is higher than the top elevation of the sand flushing corridor (3).

4. An air-cushioned sedimentation tank structure according to claim 1, characterized in that: The sand flushing corridor (3) is a longitudinal ramp with the starting point higher than the end.

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