Power plant drainage system and water diversion system using abandoned tunnel

Abstract

The application discloses a power station drainage system and water diversion system using abandoned tunnels, which comprises upper horizontal tunnel section, first long inclined shaft, middle horizontal tunnel section, second long inclined shaft, lower horizontal tunnel section and water diversion branch pipes connected in sequence from top to bottom; further comprising: middle horizontal tunnel construction branch tunnel, which is connected with the upstream side of the steel lining starting point of the middle horizontal tunnel section and is used as a drainage passage of the drainage gallery of the middle horizontal tunnel section; exploration horizontal tunnel, which intersects with the second long inclined shaft, and the intersection point is used as a construction passage to prevent angle deviation during the construction of the second long inclined shaft, and the exploration horizontal tunnel is used to set a drainage gallery of the second long inclined shaft to reduce the external water pressure of the lower pressure steel pipe in the second long inclined shaft, thereby reducing the thickness of the lower pressure steel pipe in the second long inclined shaft, and the seepage water collected by the drainage gallery of the second long inclined shaft is discharged through the early exploration horizontal tunnel of the underground powerhouse. The power station drainage system and water diversion system using abandoned tunnels can not only save investment and construction period, but also have better construction convenience and higher safety.

Description

Technical Field

[0001] This invention relates to the field of water conservancy and hydropower engineering technology, specifically to a power station drainage system and water diversion system utilizing abandoned tunnels. Background Technology

[0002] In the water diversion system, the arrangement of long inclined shafts and the setting of the power station drainage system are key aspects of the layout of pumped storage power station hubs. Their selection not only affects the regulation and guarantee performance of the water conveyance system and the layout of construction adits, but also the safety of the entire water conveyance system and the economy of the entire project cost.

[0003] Currently, the drainage systems of pumped storage power stations face challenges due to the high water pressure in the lower tunnel section. Even with steel lining, pressurized seepage from the surrounding rock outside the high-pressure pipeline is unavoidable. This seepage, acting long-term on fault alteration zones and joint fracture surfaces, is highly detrimental. To ensure the stable and safe operation of the high-pressure pipeline, especially during venting, and to prevent external water pressure from damaging the pressure pipe, it is necessary to construct drainage galleries in the lower tunnel. While drainage galleries in the lower tunnel section are widely used in pumped storage power stations, separate drainage systems in the middle tunnel and secondary inclined shafts are less common due to the high engineering investment required. Currently, the normal water level of the upper reservoir of a certain pumped storage power station is 762.0m, the centerline elevation of the high-pressure steel branch pipe is 135.71m, and the maximum static water pressure at the high-pressure branch pipe is 626.29m. Therefore, a drainage system is installed in the lower tunnel section to reduce the external water pressure on the pressure steel pipe and prevent pressurized seepage.

[0004] While constructing a drainage gallery only in the lower tunnel reduces the external water pressure on the pressure pipes in that section, thus contributing to their stable and safe operation, it fails to reduce the external water pressure on the pressure pipes in the upper and middle sections of the secondary inclined shaft and the middle tunnel within the water diversion system. This results in excessively thick walls for the pressure pipes in these sections, leading to higher project costs. Therefore, a drainage gallery is necessary in the upper and middle sections of the secondary inclined shaft and the middle tunnel. However, constructing separate drainage galleries for these sections would increase project costs and compromise construction convenience. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a power station drainage system and water diversion system that utilizes abandoned tunnels, so as to solve the problems of high external water pressure in the upper and middle sections of the existing two-stage long inclined shaft and the middle horizontal tunnel section, large wall thickness of pressure steel pipes when there is no drainage gallery in the upper and middle horizontal tunnel sections of the existing two-stage long inclined shaft, large project investment and insufficient construction convenience when setting up a separate drainage system.

[0006] To achieve the above-mentioned technical features, the objective of this invention is as follows: This invention proposes a power station drainage system and water diversion system utilizing abandoned tunnels, comprising, from top to bottom, an upper horizontal tunnel section, a first-stage long inclined shaft, a middle horizontal tunnel section, a second-stage long inclined shaft, a lower horizontal tunnel section, and a water diversion branch pipe; the upper horizontal tunnel section is equipped with an upstream surge chamber; and also includes: The construction adit of Zhongping Tunnel is connected to the upstream side of the starting point of the steel lining of Zhongping Tunnel section; The exploration tunnel is extended to intersect with the secondary inclined shaft. The intersection point also serves as a construction passage to prevent angular deviation during the construction of the secondary inclined shaft. The exploration tunnel is used to set up a drainage gallery for the secondary inclined shaft. The upstream end of the drainage gallery extends beyond the secondary inclined shaft to reduce the external water pressure on the pressure steel pipe at the secondary inclined shaft and reduce the thickness of the pressure steel pipe in the lower part of the secondary inclined shaft.

[0007] The length of the middle horizontal tunnel section is extended to shorten the length of the lower horizontal tunnel section, thereby reducing the length of the pressure steel pipe with the largest wall thickness at the lower horizontal tunnel section.

[0008] Above the lower level tunnel section, there is also a lower level tunnel drainage corridor, the upstream end of which extends beyond the second-level long inclined shaft.

[0009] The length of a secondary inclined shaft shall not exceed 500 meters.

[0010] The section from the upper level tunnel to the starting point of the steel lining is lined with concrete. Below the starting point of the steel lining, pressure steel pipes are used. The wall thickness and strength of the pressure steel pipes above the middle of the secondary long inclined shaft are less than those below the middle.

[0011] The dip angles of the first-stage and second-stage long inclined shafts are greater than the angle of repose of the rock block.

[0012] The exploration tunnel is connected to the drainage gallery of the secondary long inclined shaft, and the drainage gallery of the secondary long inclined shaft is connected to the middle part of the secondary long inclined shaft. The drainage gallery of the secondary long inclined shaft reduces the external water pressure of the pressure steel pipe in the middle of the secondary long inclined shaft.

[0013] Water collected in the secondary inclined shaft drainage corridor is discharged by gravity through the exploration tunnel of the underground powerhouse.

[0014] Drainage corridors for the Zhongping Tunnel are set up on both sides of the Zhongping Tunnel section. The drainage corridors of the Zhongping Tunnel section converge at the downstream end and connect with the construction adit of the Zhongping Tunnel.

[0015] The drainage corridor of Zhongping Tunnel reduces the external water pressure in the upper part of the secondary inclined shaft and the pressure steel pipe of Zhongping Tunnel section. The seepage water from each drainage corridor of Zhongping Tunnel section converges at the downstream end and is discharged by gravity from the construction adit of Zhongping Tunnel.

[0016] Compared with the prior art, the above-conceptual technical solution conceived in this application has the following beneficial effects: 1. This invention employs a two-stage inclined shaft system, with a construction adit in the middle horizontal tunnel section. Since the middle horizontal tunnel is lined with reinforced concrete, the water pressure is high when the elevation is low. The reinforced concrete lining will crack and leak when the internal water pressure exceeds 100m. This invention addresses this by raising the elevation of the middle horizontal tunnel and installing a drainage system for seepage prevention and drainage. The construction adit necessary for excavating the middle horizontal tunnel serves as a gravity-flow drainage channel, saving on project investment and reducing drainage operation and maintenance costs. The increased elevation of the middle horizontal tunnel increases the length of the second-stage long inclined shaft. When the length exceeds 400m, directional drilling rigs are prone to angular deviations during construction, necessitating the installation of directional boreholes in the middle to prevent these deviations. This invention addresses this by extending the exploration horizontal tunnel and, based on the existing exploration horizontal tunnel, installing a gravity-flow drainage gallery. This effectively reduces the maximum external water pressure of the second-stage long inclined shaft, improving the safety, economy, and construction convenience of the entire pumped storage power station's water diversion system. The above-mentioned method of making the most of existing construction adits or exploration tunnels to set up drainage systems, and combining them with the layout of water diversion systems, can reduce secondary excavation of tunnels, reduce the amount of drainage to be pumped out due to leakage, save on project investment, improve construction convenience, enhance safety, and lower drainage operation and maintenance costs.

[0017] 2. This invention utilizes the exploration tunnel of the underground plant to set up a secondary long inclined shaft drainage gallery. The upstream end of the secondary long inclined shaft drainage gallery extends beyond the secondary long inclined shaft, which can reduce the external water pressure of the pressure steel pipe in the lower part of the secondary long inclined shaft, thereby reducing the thickness of the pressure steel pipe in the lower part of the secondary long inclined shaft. This not only saves investment and construction time, but also makes construction more convenient and safer.

[0018] 3. In this invention, concrete lining is used between the upper horizontal tunnel section and the starting point of the steel lining. Below the starting point of the steel lining, pressure steel pipes are used. The wall thickness and strength of the pressure steel pipes above the middle of the secondary inclined shaft are less than those below the middle. Furthermore, by extending the length of the middle horizontal tunnel section and shortening the length of the lower horizontal tunnel section, the length of the pressure steel pipe section with the thickest wall at the lower horizontal tunnel section can be reduced, further lowering costs. Additionally, the number of lighter pressure steel pipe sections increases, while the number of heavier pressure steel pipe sections decreases, facilitating construction.

[0019] 4. This invention makes full use of the exploration tunnels and construction adits from the early exploration of the underground powerhouse, and modifies and sets up drainage corridors for the middle tunnel and secondary long inclined shafts. This can reduce the external water pressure at key nodes and ensure the stability of the pressure steel pipes against external pressure during the maintenance of the pumped storage power station. This arrangement greatly improves the safety of the pumped storage power station.

[0020] 5. This invention makes full use of the construction adits during construction to set up gravity drainage corridors, and uses the previously excavated exploration tunnels as the construction passage and gravity drainage corridor for the secondary long inclined shaft. There is no need to excavate additional construction adits, which greatly reduces the amount of work, saves project investment, reduces leakage drainage costs, and improves construction safety. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic longitudinal section of the present invention.

[0023] Figure 2 This is a schematic plan view of the drainage system of the construction adit of the Zhongping Tunnel according to the present invention.

[0024] Figure 3 This is a schematic plan view of the drainage system based on the exploration tunnel of the present invention.

[0025] Figure 4 This is a schematic diagram of the drainage corridor in the lower horizontal tunnel section of the present invention.

[0026] In the picture: 1. Upstream surge tank; 2. Upper horizontal tunnel section; 3. First-stage long inclined shaft; 4. Middle horizontal tunnel section; 5. Steel lining starting point; 6. Middle horizontal tunnel construction adit; 7. Second-stage long inclined shaft; 8. Exploration horizontal tunnel; 9. Second-stage long inclined shaft drainage gallery; 10. Middle horizontal tunnel drainage gallery; 11. Lower horizontal tunnel drainage gallery; 12. Lower horizontal tunnel section; 13. Water diversion branch pipe. Detailed Implementation

[0027] To more clearly illustrate the purpose, technical solution, and beneficial effects of this application, a further detailed description of this application is provided below in conjunction with illustrations and specific embodiments. It should be specifically noted that the specific embodiments described below are only for illustrating the technical content of this application and do not constitute a limitation on the scope of protection of this application.

[0028] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "inner," and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present application. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0029] In the description of this invention, unless otherwise explicitly specified and limited, the term "connection" or similar designation indicating a connection between components should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection via an intermediate medium; it can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0030] Example 1: like Figure 1 As shown, a power station drainage system and water diversion system utilizing abandoned tunnels include: Upper Ping Tunnel Section 2 is connected to the upper reservoir at its upstream end and to the top of the first-stage long inclined shaft 3 at its downstream end; Upper Ping Tunnel Section 2 is equipped with an upstream pressure regulating chamber 1; Zhongping Tunnel Section 4: The upstream end of Zhongping Tunnel Section 4 is connected to the bottom end of the first-stage long inclined shaft 3, and the downstream end is connected to the top end of the second-stage long inclined shaft 7 through the steel lining starting point 5. The lower horizontal tunnel section 12 is connected to the bottom of the secondary long inclined shaft 7 at its upstream end and to the starting end of the water diversion branch pipe 13 at its end; the end of the water diversion branch pipe 13 is connected to the power station.

[0031] It also includes: Zhongping Tunnel Construction Adit 6, which is a gravity drainage corridor. Zhongping Tunnel Construction Adit 6 is connected to Zhongping Tunnel Section 4 on the upstream side of the starting point 5 of the steel lining. Exploration tunnel 8 is located between the middle tunnel section 4 and the lower tunnel section 12. Exploration tunnel 8 extends to intersect with the secondary long inclined shaft 7. The intersection also serves as a construction passage to prevent angular deviation during the construction of the secondary long inclined shaft 7. The exploration tunnel 8 is used to set up a drainage gallery 9 for the secondary long inclined shaft. The upstream end of the drainage gallery 9 extends beyond the secondary long inclined shaft 7 to reduce the external water pressure on the pressure steel pipe in the middle and lower part of the secondary long inclined shaft 7, reduce the thickness or strength of the pressure steel pipe in the middle and lower part of the secondary long inclined shaft 7, and reduce the manufacturing cost of the secondary long inclined shaft 7.

[0032] See Figure 1 and 3 The water collected in the secondary inclined shaft drainage gallery 9 is discharged by gravity through the exploration tunnel 8 of the underground powerhouse.

[0033] In this embodiment, concrete lining is used between the upper horizontal tunnel section 2 and the starting point 5 of the steel lining, and pressure steel pipe is used below the starting point 5 of the steel lining. The thickness and strength of the pressure steel pipe in the upper part of the secondary long inclined shaft 7 are less than the thickness and strength in the lower part.

[0034] Furthermore, by extending the length of the middle horizontal tunnel section 4, the length of the lower horizontal tunnel section 12 is shortened, reducing the length of the pressure steel pipe at the section with the thickest wall in the lower horizontal tunnel section 12, thus further reducing costs. Additionally, the number of lighter pressure steel pipe sections increases, while the number of heavier pressure steel pipe sections decreases, resulting in better construction convenience and higher safety.

[0035] See Figure 1 and 4 Above the lower horizontal tunnel section 12, a lower horizontal tunnel drainage gallery 11 is also provided, with its upstream end extending beyond the secondary long inclined shaft 7. This is to reduce the external water pressure on the pressure steel pipe at the lower end of the secondary long inclined shaft 7.

[0036] In this embodiment, the length of the secondary long inclined shaft 7 does not exceed 500 meters to facilitate the construction of the secondary long inclined shaft.

[0037] In this embodiment, the inclination angles of the first-stage long inclined shaft 3 and the second-stage long inclined shaft 7 are approximately 55°, which is greater than the angle of repose of the rock block.

[0038] The exploration tunnel 8 extends and intersects with the middle section of the secondary long inclined shaft 7. The intersection point also serves as a construction passage. To prevent angular deviations from the directional drilling rig during the construction of the secondary long inclined shaft 7, a gravity-flow drainage gallery is constructed using the exploration adit 8 to reduce the external water pressure on the pressure steel pipe.

[0039] See Figure 1 and 2 Drainage corridors 10 are installed on both sides of the middle tunnel section 4 to reduce the external water pressure in the upper part of the middle tunnel section 4 and the secondary long inclined shaft 7. The seepage water from each drainage corridor 10 flows downstream and is discharged by gravity from the middle tunnel construction adit 6, reducing the operation and maintenance cost of the drainage corridors.

[0040] The drainage corridor 10 in Zhongping Tunnel reduces the external water pressure in the upper part of the secondary long inclined shaft 7 and the pressure steel pipes in the four locations of Zhongping Tunnel, thereby reducing the wall thickness of the pressure steel pipes in the upper part of the secondary long inclined shaft 7 and the four locations of Zhongping Tunnel.

[0041] Example 2: like Figure 2 As shown, the construction adit 6 of the Zhongping Tunnel is located in the middle of the Zhongping Tunnel section 4. The Zhongping Tunnel section 4 is lined with concrete. The end of the Zhongping Tunnel section 4 is connected to the top of the secondary long inclined shaft 7 through the steel lining starting point 5. Since the Zhongping Tunnel section 4 is lined with concrete, in order to avoid leakage caused by hydraulic fracturing due to high internal water pressure, the elevation of the Zhongping Tunnel section 4 is increased and a drainage system is set up around the Zhongping Tunnel section 4 to reduce the internal and external water pressure. Ten rows of drainage corridors are arranged around the pipes at the end of the Zhongping Tunnel section 4, and drainage is carried out using the Zhongping Tunnel construction adit 6. There is no need to excavate drainage corridors separately, which reduces project investment and improves construction convenience.

[0042] like Figure 3 As shown, a two-stage long inclined shaft drainage gallery 9 is set up in the existing exploration tunnel 8 of the project.

[0043] The exploration tunnel 8 is located in the middle of the secondary inclined shaft 7. Since the length of the secondary inclined shaft 7 in this embodiment exceeds 400m, drilling from bottom to top will cause angular deviations, requiring a directional point to be set in the middle of the secondary inclined shaft 7 for correction. Therefore, this embodiment uses the intersection of the extended exploration tunnel 8 and the lower tunnel 7 as the directional point. Simultaneously with determining the directional point, the extended portion of the exploration tunnel can be designated as a drainage gallery. For example... Figure 3 As shown, drainage is installed near the pressure steel pipe to reduce the external water pressure on the pipe, and the exploration tunnel is used as a drainage gallery. This design eliminates the need for a separate drainage gallery, reducing project costs and improving construction convenience.

[0044] This application makes full use of the exploration tunnels and construction adits from the early exploration of the underground powerhouse, and modifies and sets up drainage corridors for the middle tunnel and secondary long inclined shafts. This can reduce the external water pressure at key nodes and ensure the stability of the pressure steel pipes against external pressure during the maintenance of the pumped storage power station. This arrangement greatly improves the safety of the pumped storage power station.

[0045] This application makes full use of the construction adits during construction to set up gravity drainage corridors, and uses the previously excavated exploration tunnels as the construction passage and gravity drainage corridor for the secondary long inclined shaft. There is no need to excavate additional construction adits, which greatly reduces the amount of work, saves project investment, reduces leakage drainage costs, and improves construction safety.

[0046] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims. Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A power station drainage system and water diversion system utilizing abandoned tunnels, characterized in that, It includes, from top to bottom, the upper horizontal tunnel section (2), the first-stage long inclined shaft (3), the middle horizontal tunnel section (4), the second-stage long inclined shaft (7), the lower horizontal tunnel section (12), and the water diversion branch pipe (13); the upper horizontal tunnel section (2) is equipped with an upstream pressure regulating chamber (1); it also includes: The construction adit (6) of Zhongping Tunnel is connected to the upstream side of the starting point (5) of the steel lining of Zhongping Tunnel (4), and also serves as the drainage channel of the drainage corridor of Zhongping Tunnel (4). The exploration tunnel (8) is extended to intersect with the secondary long inclined shaft (7). The intersection point also serves as a construction passage to prevent angular deviation during the construction of the secondary long inclined shaft (7). The exploration tunnel (8) is used to set up a drainage gallery (9) for the secondary long inclined shaft. The upstream end of the drainage gallery (9) extends beyond the secondary long inclined shaft (7) to reduce the external water pressure of the pressure steel pipe at the secondary long inclined shaft (7) and reduce the thickness of the pressure steel pipe in the lower part of the secondary long inclined shaft (7).

2. The power station drainage system and water diversion system utilizing abandoned tunnels according to claim 1, characterized in that: The length of the middle tunnel section (4) is extended to shorten the length of the lower tunnel section (12) and reduce the length of the pressure steel pipe with the largest wall thickness at the lower tunnel section (12).

3. A power station drainage system and water diversion system utilizing abandoned tunnels according to claim 1, characterized in that: Above the lower level tunnel section (12), there is also a lower level tunnel drainage gallery (11), the upstream end of which exceeds the secondary long inclined shaft (7).

4. A power station drainage system and water diversion system utilizing abandoned tunnels according to claim 1, characterized in that: The length of the second-stage long inclined shaft (7) shall not exceed 500 meters.

5. A power station drainage system and water diversion system utilizing abandoned tunnels according to claim 1 or 4, characterized in that: Concrete lining is used between the upper flat tunnel section (2) and the starting point of the steel lining (5). Pressure steel pipes are used below the starting point of the steel lining (5), and the wall thickness and strength of the pressure steel pipes above the middle of the secondary long inclined shaft (7) are less than the wall thickness and strength below the middle.

6. A power station drainage system and water diversion system utilizing abandoned tunnels according to claim 1, characterized in that: The dip angles of the first-stage long inclined shaft (3) and the second-stage long inclined shaft (7) are greater than the rock block repose angle.

7. A power station drainage system and water diversion system utilizing abandoned tunnels according to claim 1, characterized in that: The exploration tunnel (8) is connected to the drainage gallery (9) of the secondary long inclined shaft. The drainage gallery (9) of the secondary long inclined shaft is connected to the middle part of the secondary long inclined shaft (7). The drainage gallery (9) of the secondary long inclined shaft reduces the external water pressure of the pressure steel pipe in the lower part of the secondary long inclined shaft (7).

8. A power station drainage system and water diversion system utilizing abandoned tunnels according to claim 1, characterized in that: Water collected in the secondary inclined shaft drainage gallery (9) is discharged by gravity through the exploration tunnel (8) of the underground powerhouse.

9. A power station drainage system and water diversion system utilizing abandoned tunnels according to claim 1, characterized in that: Drainage corridors (10) are set up on both sides of the Zhongping Tunnel section (4). Each Zhongping Tunnel drainage corridor (10) is connected to the Zhongping Tunnel construction branch tunnel (6) after the downstream end of the drainage corridors (10).

10. A power station drainage system and water diversion system utilizing abandoned tunnels according to claim 9, characterized in that: The drainage corridor (10) of Zhongping Tunnel reduces the external water pressure of the upper part of the secondary long inclined shaft (7) and the pressure steel pipe of Zhongping Tunnel section (4). The seepage water of each drainage corridor (10) of Zhongping Tunnel section flows downstream and is discharged by gravity from the construction branch tunnel (6) of Zhongping Tunnel.

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