Composite tailrace tunnel structure for hydropower and pumped storage engineering
By introducing guide walls and composite tailrace transport structures into hydropower projects, multiple tailrace tunnels can be drained independently, solving the problems of construction cost and difficulty when connecting tailrace tunnels to guide tunnels, and realizing the efficient utilization of guide tunnels.
Patent Information
- Application Number
- CN202520113030.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-16
- Publication Date
- 2026-01-20
- Estimated Expiration
- 2035-01-16
AI Technical Summary
In existing hydropower projects, when multiple tailrace tunnels are connected to diversion tunnels, it is necessary to build new tailrace surge chambers or gate chambers, which increases project investment and construction difficulty. In addition, the diversion tunnels are not fully utilized and lack flexible layout methods.
The system adopts a composite tailrace tunnel structure, including a diversion tunnel, a front tailrace tunnel, a diversion wall, and a composite tailrace transport structure. The tailrace water of each generator unit is discharged independently to the downstream river channel or reservoir area through the diversion wall, and the independent drainage of multiple tailrace tunnels is achieved by utilizing the existing diversion tunnel.
This significantly reduces construction costs and difficulties, makes full use of diversion tunnel resources, enables independent drainage of multiple tailrace tunnels, and reduces investment in new tailrace tunnels.
Smart Images
Figure CN223813733U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a composite tailrace tunnel structure, in particular to a composite tailrace tunnel structure for water and electricity and pumped storage engineering, belongs to water conservancy and hydropower engineering structure design and construction technical field. BACKGROUND
[0002] In the hydropower engineering, the temporary diversion tunnel in the construction period is used to change a part of the power generation tailrace tunnel, realizes the combination of permanent and temporary, not only can make the engineering layout more flexible, but also can greatly save the engineering investment, so it is very necessary to use it reasonably.
[0003] At present, the tailrace tunnel combined with the diversion tunnel is more used in large-scale hydropower engineering, but from the layout method, all adopt one tailrace tunnel to access one diversion tunnel for layout, and the layout method of two or more tailrace tunnels accessing the diversion tunnel has not been used, so the method still has certain limitations.
[0004] When the number of diversion tunnels is less than the number of units, multiple tailrace tunnels need to be combined indoors or outdoors, and then access the diversion tunnel, at this time, the tailrace tunnel front end needs to be arranged with a tailrace surge chamber or a tailrace gate chamber, otherwise it cannot meet the needs of unit maintenance; when the tailrace tunnel front end is not arranged with a tailrace surge chamber or a tailrace gate chamber, only part of the tailrace tunnel can use the diversion tunnel, and part of the new tailrace tunnel is built, which leads to insufficient utilization of the diversion tunnel, and the engineering investment is not significantly saved, and the layout difficulty is increased, and the construction risk and difficulty are increased.
[0005] Considering that the demand of hydropower engineering and pumped storage power station construction in China is large, and the method of changing the diversion tunnel into the tailrace tunnel meets the target concept of safety, environmental protection, energy saving, economy and the like, has broad application space in the future, and the current layout method still has certain limitations, it is urgent to adopt new layout structure and layout method to realize that one diversion tunnel meets the access and utilization of two or more tailrace tunnels, more fully utilizes the combination of permanent and temporary, and saves engineering investment and construction difficulty. UTILITY MODEL CONTENTS
[0006] The utility model solves the technical problem that a composite tailrace tunnel structure for water and electricity and pumped storage engineering can significantly reduce construction cost and effectively reduce construction difficulty.
[0007] The technical scheme adopted to solve the above technical problems is: a composite tailrace tunnel structure for water and electricity and pumped storage projects, comprising a diversion tunnel, the composite tailrace tunnel structure further comprising a front tailrace tunnel, a diversion wall and a composite tailrace conveying structure, the number of the front tailrace tunnels being equal to the number of external generator sets, the output ends of each front tailrace tunnel being simultaneously connected to the tail end of the diversion tunnel under the cooperation of the diversion wall, and the composite tailrace conveying structure being arranged in the tail end of the diversion tunnel connected to the composite tailrace tunnel structure through the diversion wall along the water flow direction; the tail water output by each generator set is independently discharged into the downstream river or the downstream reservoir area through the front tailrace tunnel and the tail end of the diversion tunnel under the cooperation of the diversion wall and the composite tailrace conveying structure.
[0008] Further, the diversion wall is a water-stopping wall arranged in the diversion tunnel, the water-stopping wall extending along the upstream side wall of the upstream side front tailrace tunnel, and the tail end of the diversion tunnel connected to the composite tailrace tunnel structure being separated from the middle and front diversion tunnels not connected to the composite tailrace tunnel structure by the water-stopping wall.
[0009] The preferred mode of the above scheme is that the water-stopping wall and the downstream side wall of the diversion tunnel are connected through an inscribed concentric arc transition, the radius of the inscribed concentric arc being not less than 5 m, the water-stopping wall and the diversion tunnel wall are connected as a whole through the embedded bars at the connection position.
[0010] Further, the composite tailrace conveying structure comprises at least a middle partition wall, the number of the middle partition walls being adapted to the number of the front tailrace tunnels, each middle partition wall separating the tail end of the diversion tunnel into a plurality of tailrace conveying channels along the water flow direction, the number of the tailrace conveying channels being equal to the number of the front tailrace tunnels, the input end of each tailrace conveying channel being connected to each front tailrace tunnel one by one, and the output end of each tailrace conveying channel being independently connected to the downstream river or the downstream reservoir area.
[0011] The preferred mode of the above scheme is that each middle partition wall is a concrete wall, the projection of each concrete wall in the cross section thereof being a regular isosceles trapezoid, and the lower end of the isosceles trapezoid and the bottom plate of the diversion tunnel being connected as a whole through the embedded bars.
[0012] Further, a length-extending air pressure plate is arranged on the top of each middle partition wall.
[0013] The preferred mode of the above scheme is that the air pressure plate is integrally formed on the top of each middle partition wall, the thickness of the air pressure plate being not less than 0.5 m, the width of the air pressure plate being not less than 1 m, and the bottom surface of the air pressure plate and the two side surfaces of the middle partition wall being connected through a circular arc structure, the radius of the circular arc structure being not less than 2 m.
[0014] Further, the composite tail water conveying structure further comprises a number of flow splitting piers, the number of which is adapted to the number of the front-stage tail water tunnels, and each of the partition walls is connected to a corresponding position of the upstream sidewall of the diversion tunnel through a flow splitting pier independently.
[0015] Preferably, the tail water gate system is further arranged at the output end of each tail water conveying channel.
[0016] Further, an air vent is arranged at the end of the front-stage tail water tunnel intersecting with the diversion tunnel.
[0017] The beneficial effects of the present application are as follows: the technical scheme provided by the present application is based on the existing diversion tunnel, and the front-stage tail water tunnel, the diversion wall and the composite tail water conveying structure are arranged to form the composite tail water tunnel structure of the present application, so that the number of the front-stage tail water tunnels is equal to the number of the external generator sets, and then the output ends of the front-stage tail water tunnels are connected to the end-stage diversion tunnels under the cooperation of the diversion wall, and the composite tail water conveying structure is arranged in the end-stage diversion tunnel connected to the composite tail water tunnel structure through the diversion wall along the water flow direction; thus, the tail water output by each generator set is independently discharged into the downstream river or the downstream reservoir area through the front-stage tail water tunnel and the end-stage diversion tunnel under the cooperation of the diversion wall and the composite tail water conveying structure. The technical scheme solves the technical problems that the diversion tunnel cannot be used or one tail water tunnel is used with one diversion tunnel in the prior art, and when the number of the tail water tunnels is greater than the number of the diversion tunnels, the tail water tunnels must be newly built. The above technical scheme of the present application can achieve the purpose that the tail water output by each generator set is independently discharged into the downstream river or the downstream reservoir area through the front-stage tail water tunnel and the end-stage diversion tunnel under the cooperation of the diversion wall and the composite tail water conveying structure, reduces the investment of the newly built tail water tunnels, and significantly reduces the construction cost and the construction difficulty. BRIEF DESCRIPTION OF DRAWINGS
[0018] Figure 1 FIG. 1 is a planar arrangement structure schematic diagram of the composite tail water tunnel structure of the present application for hydropower and pumped storage projects;
[0019] Figure 2 FIG. 2 is an A-A sectional view of the composite tail water tunnel structure of the present application. Figure 1
[0020] In the figure, the marks are as follows: diversion tunnel 1, front-stage tail water tunnel 2, diversion wall 3, partition wall 4, tail water conveying channel 5, reinforcing bar 6, air pressure plate 7, flow splitting pier 8, tail water gate system 9, air vent 10. DETAILED DESCRIPTION
[0021] For example, Figure 1 , Figure 2 The utility model provides a kind of composite tailrace tunnel structure for water and electricity and pumped storage project, which can significantly reduce construction cost and effectively reduce construction difficulty. The composite tailrace tunnel structure includes a diversion tunnel 1. The composite tailrace tunnel structure further includes a front tailrace tunnel 2, a diversion wall 3 and a composite tailrace conveying structure. The number of front tailrace tunnels 2 is equivalent to the number of external generator sets. The output ends of each front tailrace tunnel 2 are connected to the end section of the diversion tunnel 1 under the cooperation of the diversion wall 3. The composite tailrace conveying structure is arranged in the end section diversion tunnel connected to the composite tailrace tunnel structure through the diversion wall 3 along the water flow direction. The tailrace output by each generator set is independently discharged into the downstream river or downstream reservoir area through the front tailrace tunnel 2 and the end section diversion tunnel under the cooperation of the diversion wall 3 and the composite tailrace conveying structure. The technical solution provided by the present application is based on the existing diversion tunnel. By increasing the front tailrace tunnel, the diversion wall and the composite tailrace conveying structure, the number of front tailrace tunnels constructed is equivalent to the number of external generator sets. Then, the output ends of each front tailrace tunnel are connected to the end section of the diversion tunnel under the cooperation of the diversion wall. The composite tailrace conveying structure is arranged in the end section diversion tunnel connected to the composite tailrace tunnel structure through the diversion wall along the water flow direction. Thus, the tailrace output by each generator set is independently discharged into the downstream river or downstream reservoir area through the front tailrace tunnel and the end section diversion tunnel under the cooperation of the diversion wall and the composite tailrace conveying structure. This solves the technical problem in the prior art that either the diversion tunnel cannot be used or one tailrace tunnel uses one diversion tunnel. When the number of tailrace tunnels is greater than the number of diversion tunnels, new tailrace tunnels must be built. By using the above technical solution of the present application, the tailrace output by each generator set can be independently discharged into the downstream river or downstream reservoir area through the front tailrace tunnel and the end section diversion tunnel under the cooperation of the diversion wall and the composite tailrace conveying structure. This reduces the investment in building new tailrace tunnels and significantly reduces construction cost and effectively reduces construction difficulty.
[0022] Correspondingly, in order to improve the flow state of the output tailrace, the diversion wall 3 of the present application is a water cutoff wall arranged in the diversion tunnel 1. The water cutoff wall extends along the upstream side wall of the upstream side front tailrace tunnel. The end section diversion tunnel connected to the composite tailrace tunnel structure is separated from the middle and front section diversion tunnels not connected to the composite tailrace tunnel structure by the water cutoff wall. Preferably, the water cutoff wall and the downstream side wall of the diversion tunnel are connected by an inscribed concentric circular arc with a radius not less than 5 m. The insertion rib is arranged at the connection position of the water cutoff wall and the diversion tunnel wall. The water cutoff wall is connected to the diversion tunnel concrete as a whole through the insertion rib.
[0023] Further, as the key structure improved by the present application, in order to make full use of the existing diversion tunnel while simplifying the structure as much as possible and ensuring the best flow state, the composite tail water delivery structure of the present application at least includes the middle partition wall 4, the number of the middle partition wall 4 is adapted to the number of the front-stage tail water tunnel 2, each middle partition wall 4 separates the last-stage diversion tunnel along the width direction into a plurality of tail water delivery channels 5 with a number corresponding to the number of the front-stage tail water tunnel 2, the input end of each tail water delivery channel 5 is one-to-one corresponding to each front-stage tail water tunnel 2, and the output end of each tail water delivery channel 5 is independently connected to the downstream river channel or the downstream reservoir area. In combination with the actual situation of the hydropower project, each middle partition wall 4 of the present application is a concrete wall, the projection of each concrete wall in the cross section is a regular isosceles trapezoid, and the lower end of the isosceles trapezoid is connected to the bottom plate of the diversion tunnel 1 through the dowel bar 6 to form an integral whole. Meanwhile, a length-extended air pressure plate 7 is arranged on the top of each middle partition wall 4. At this time, the preferred structure is that the air pressure plate 7 is integrally formed on the top of each middle partition wall 4, the thickness of the air pressure plate 7 is not less than 0.5 meters, the width of the air pressure plate 7 is not less than 1 meter, and the bottom surface of the air pressure plate 7 and the two side surfaces of the middle partition wall 4 are connected through a circular arc structure with a radius of not less than 2 meters. Correspondingly, the composite tail water delivery structure of the present application further includes a flow divider 8, the number of the flow divider 8 is adapted to the number of the front-stage tail water tunnel 2, and each middle partition wall 4 is independently connected to the corresponding position of the upstream side wall of the diversion tunnel through a flow divider 8.
[0024] In combination with the actual situation of the project, in order to avoid the flow between the outputs of the tail water tunnels as much as possible, the height of each middle partition wall 4 is obtained according to the following formula,
[0025] H = H0 + a,
[0026] wherein H0 is the maximum water depth (including the running water head) of the tail water tunnel after being connected to the diversion tunnel, and the unit is meter; a is the safety super-elevation, and the unit is meter, which is generally not less than 0.3 meters.
[0027] Meanwhile, in order to avoid the backflow of the water flow in the downstream river channel or the reservoir area when the generator set is detected, a tail water gate system 9 is arranged at the output end of each tail water delivery channel 5, and an air vent 10 is arranged at the end of the front-stage tail water tunnel 2 intersecting with the diversion tunnel 1.
[0028] As described above, by means of the preferred design of the building structure provided by the present application, the hydraulic conditions of the tail water tunnel combined with the diversion tunnel can be completely met, the permanent and temporary combination can be fully utilized, the arrangement method is novel, and the safety, environmental protection, economy and energy saving concepts are met.
[0029] The technical scheme of the present application will be further described through specific embodiments as follows:
[0030] Embodiment one
[0031] To make up for the current limitations of the arrangement of the diversion tunnel for tailrace tunnel, the technical problem solved by the present application is to provide an arrangement structure of the diversion tunnel for tailrace tunnel, so as to realize the utilization of the same diversion tunnel for two or more tailrace tunnels. The specific requirements are as follows,
[0032] 1. The size of the diversion tunnel can meet the flow capacity requirements of multiple tunnels under various operating conditions.
[0033] 2. The angle of the tailrace tunnel entering the diversion tunnel should not be too large, generally not more than 50°, otherwise it may cause a large scouring on the side wall, and special measures need to be taken.
[0034] The technical solution adopted by the present application to solve the above technical problem is an arrangement structure of the diversion tunnel for tailrace tunnel, which comprises a diversion tunnel and a tailrace tunnel, and the diversion tunnel is internally provided with a water guide wall structure, a tailrace separation wall, a partition wall foundation and a reinforcing bar, a top pressing plate, an air vent, a flow divider and a tailrace control gate.
[0035] The water guide wall is arranged on the upstream side of the partition wall, that is, as a water guide structure, and also as the side wall of the tailrace tunnel entering the diversion tunnel on the upstream side, to ensure the orderly flow and smooth flow pattern. The arrangement direction of the water guide wall is generally extended along the side wall of the most upstream tailrace tunnel, and smoothly connected with the side wall of the diversion tunnel.
[0036] The connection part of the water guide wall and the side wall of the diversion tunnel adopts an internal tangent concentric arc of the internal side wall, and the radius of the arc is generally not less than 5m. The connection part of the water guide wall and the side wall of the diversion tunnel is provided with a reinforcing bar, which is connected with the concrete of the diversion tunnel as a whole.
[0037] The water guide wall can adopt a concrete structure, a mortar stone structure or a brick wall structure. Its shape can be selected as a rectangle, a trapezoid, etc., and its height is the same as that of the partition wall.
[0038] The tailrace separation wall is arranged in parallel with the axis of the diversion tunnel, and its shape is preferably a trapezoidal structure.
[0039] The tailrace separation wall is preferably made of concrete with a strength grade not less than C25. The height of the partition wall is determined according to the following method.
[0040] 1) When the reconstructed diversion tunnel is operated as a pressure tunnel, the water flow in the diversion tunnel is in a full state, and at this time the top elevation of the partition wall is the elevation where the partition wall intersects with the diversion tunnel.
[0041] 2) When the reconstructed diversion tunnel is operated as a non-pressure tunnel, the water level in the diversion tunnel is a free water surface, and the determination of the height of the partition wall is H=H0+a, wherein H0 is the maximum water depth (including the running water head) after the tailrace tunnel enters the diversion tunnel, and the unit is m; a is a safety super-elevation, and the unit is m, which is generally not less than 0.3m.
[0042] The bottom of the partition wall foundation is generally set on the rock of the diversion tunnel foundation surface and below it. The connecting part of the diversion tunnel and the foundation side should be chiseled.
[0043] The partition wall foundation is effectively connected with the bottom rock through the inserted reinforcement. The length of the inserted reinforcement into the rock should not be less than 40d, where d is the diameter of the inserted reinforcement.
[0044] The air pressure plate structure of the partition wall top is arranged on the top of the partition wall, which is mainly used to improve the local flow state and make the water flow more smooth, so as to avoid the local water flow rolling too much after the tailrace tunnel is connected to the diversion tunnel.
[0045] The thickness of the air pressure plate structure is not less than 0.5 meters, and the width is generally not less than 1 meter. The lower part adopts a circular arc structure with a radius of not less than 2 meters.
[0046] The air vent structure is generally arranged near the part where the tailrace tunnel is connected to the diversion tunnel, extending from the top of the diversion tunnel to the outside.
[0047] In order to further realize the separate operation of each tailrace tunnel in the diversion tunnel, a flow dividing pier is arranged between the tailrace tunnels.
[0048] The tailwater control gate is arranged at the outlet of the diversion tunnel, which can fully utilize the conditions of the already built diversion tunnel, facilitate the reconstruction construction, and does not produce slope excavation, meet the independent operation of each tailrace tunnel, and maintenance.
Claims
1. A composite tailrace structure for hydroelectric and pumped storage projects, comprising a diversion tunnel (1), characterized in that: The composite tailrace tunnel structure further comprises front-stage tailrace tunnels (2), a guide wall (3) and a composite tailrace conveying structure. The number of the front-stage tailrace tunnels (2) is equal to the number of the external generator units. The output ends of the front-stage tailrace tunnels (2) are respectively connected to the end-stage of the diversion tunnel (1) under the cooperation of the guide wall (3). The composite tailrace conveying structure is arranged in the end-stage diversion tunnel connected to the composite tailrace tunnel structure through the guide wall (3) along the water flow direction. The tailwater discharged by each generator unit is independently discharged into the downstream river or the downstream reservoir area through the front-stage tailrace tunnels (2) and the end-stage diversion tunnel under the cooperation of the guide wall (3) and the composite tailrace conveying structure.
2. The composite tailrace structure for hydroelectric and pumped storage projects according to claim 1, characterized in that: The guide wall (3) is a water-stopping wall arranged in the diversion tunnel (1). The water-stopping wall extends along the upstream side wall of the front-stage tailrace tunnel on the upstream side. The end-stage diversion tunnel connected to the composite tailrace tunnel structure is separated from the middle-stage and front-stage diversion tunnels not connected to the composite tailrace tunnel structure by the water-stopping wall.
3. The composite tailrace structure for hydroelectric and pumped storage projects according to claim 2, characterized in that: The water-stopping wall and the downstream side wall of the diversion tunnel are connected by an inscribed concentric arc transition. The radius of the inscribed concentric arc is not less than 5 m. The water-stopping wall and the diversion tunnel wall are connected by a dowel. The water-stopping wall is connected to the diversion tunnel concrete as a whole through the dowel.
4. The composite tailrace structure for hydroelectric and pumped storage projects according to claim 1, 2 or 3, characterized in that: The composite tailrace conveying structure at least comprises middle partition walls (4). The number of the middle partition walls (4) is adapted to the number of the front-stage tailrace tunnels (2). Each middle partition wall (4) separates the end-stage diversion tunnel into a plurality of tailrace conveying channels (5) along the water flow direction. The number of the tailrace conveying channels (5) is equal to the number of the front-stage tailrace tunnels (2). The input ends of the tailrace conveying channels (5) are respectively connected to the front-stage tailrace tunnels (2) one by one. The output ends of the tailrace conveying channels (5) are respectively and independently connected to the downstream river or the downstream reservoir area.
5. The composite tailrace structure for hydroelectric and pumped storage projects according to claim 4, characterized in that: Each middle partition wall (4) is a concrete wall. The projection of each middle partition wall (4) in the cross section is a regular isosceles trapezoid. The lower end of the isosceles trapezoid is connected to the bottom plate of the diversion tunnel (1) as a whole through a dowel (6).
6. The composite tailrace structure for hydroelectric and pumped storage projects according to claim 5, characterized in that: A length-extending air pressure plate (7) is arranged on the top of each middle partition wall (4).
7. The composite tailrace structure for hydroelectric and pumped storage projects according to claim 6, characterized in that: The air pressure plate (7) is integrally formed on the top of each middle partition wall (4). The thickness of the air pressure plate (7) is not less than 0.5 m. The width of the air pressure plate (7) is not less than 1 m. The bottom surface of the air pressure plate (7) and the two side surfaces of the middle partition wall (4) are connected by a circular arc structure transition. The radius of the circular arc structure is not less than 2 m.
8. The composite tailrace structure for hydroelectric and pumped storage projects according to claim 7, characterized in that: The composite tailrace conveying structure further comprises a flow divider (8). The number of the flow dividers (8) is adapted to the number of the front-stage tailrace tunnels (2). Each middle partition wall (4) is respectively and independently connected to the corresponding position of the upstream side wall of the diversion tunnel through a flow divider (8).
9. The composite tailrace structure for hydroelectric and pumped storage projects according to claim 4, characterized in that: A tailwater gate system (9) is arranged at the output end of each tailrace conveying channel (5).
10. The composite tailrace structure for hydroelectric and pumped storage projects according to claim 4, characterized in that: An air vent (10) is arranged at the end of the front-stage tailrace tunnel (2) intersecting with the diversion tunnel (1).