Water diversion system and parameter determination method satisfying pressure requirement of upper tunnel section

Abstract

The application relates to the technical field of water conservancy and hydropower engineering, and provides a water diversion system of a hydropower station satisfying pressure requirements of an upper tunnel section and a parameter determination method, which comprises an upper reservoir vertical shaft type water inlet and outlet, an upper tunnel section, one end of the upper tunnel section being communicated with the bottom end of the upper reservoir vertical shaft type water inlet and outlet, a first inclined shaft, one end of the first inclined shaft being communicated with the end of the upper tunnel section, a lower tunnel section, one end of the lower tunnel section being communicated with the bottom end of the first inclined shaft, a flat bottom type lower tunnel section, a water diversion steel branch pipe, a water diversion steel branch pipe, an underground powerhouse exploration tunnel, the underground powerhouse exploration tunnel being located at the upper part of an underground powerhouse, a middle construction branch tunnel, the middle construction branch tunnel being communicated with the underground powerhouse exploration tunnel and the lower part of the first inclined shaft. The application can more ensure that the minimum pressure water head of the end of the upper tunnel section satisfies design requirements, guarantee the safe and stable operation of a pumped storage power station, improve the benefit of the pumped storage power station, shorten the construction period of the project, and reduce the project investment.

Description

Technical Field

[0001] This invention relates to the field of water conservancy and hydropower engineering technology, and in particular to a water diversion system for a hydropower station that meets the pressure requirements of the Shangpingdong section and a method for determining its parameters. Background Technology

[0002] The selection of the facade layout structure of the water diversion system is a key and challenging aspect of the layout of the pumped storage power station hub. Its selection is affected by topographic and geological conditions, the form of the upper reservoir inlet and outlet, the closing time requirements of the emergency maintenance gates of the upper reservoir inlet and outlet, the minimum pressure requirements at the end of the upper horizontal tunnel section of the water diversion, the starting position of the steel lining, the location of the underground powerhouse and the length of its auxiliary caverns, the layout of construction adits, and the safety and convenience of construction site management.

[0003] Currently, most pumped storage power station water diversion systems in China consist of an upper reservoir side-mounted inlet / outlet + emergency maintenance gate + upper horizontal section + upper inclined shaft or upper vertical shaft + middle horizontal tunnel section + lower inclined shaft or lower vertical shaft + lower horizontal tunnel section. This arrangement is affected by the coordination between the upper reservoir side-mounted inlet / outlet layout and the upper reservoir basin layout. After the upper reservoir side-mounted inlet / outlet meets the minimum submergence depth requirement, its bottom elevation will not be further reduced. This results in the centerline elevation of the water diversion tunnel after the upper reservoir side-mounted inlet / outlet generally being relatively high, which further leads to the following problems:

[0004] The extension length of the lower-investment upper horizontal tunnel is limited, while the length of the higher-investment middle and lower horizontal tunnels is increased. The investment in auxiliary caverns such as the access tunnel, ventilation and safety tunnel, and outgoing line tunnel of the underground powerhouse of a pumped storage power station is substantial. Furthermore, when the underground powerhouse is located at the head, the burial depth is large, resulting in greater ground stress, which is detrimental to the stability of the surrounding rock of a large-span underground powerhouse. Therefore, in the layout of the pumped storage power station hub, the underground powerhouse generally adopts a middle or tail-end scheme. When the underground powerhouse adopts a middle or tail-end scheme, in order to reduce the length of the high-pressure steel pipe section of the lower horizontal tunnel, which requires a larger investment, the length of the lower-pressure upper horizontal tunnel needs to be increased. However, due to the elevation limitations of the side-mounted inlet and outlet of the upper reservoir, and to meet the minimum pressure requirement of not less than 2m head at the end of the upper horizontal tunnel, the length of the upper horizontal tunnel is limited. Its extension length generally does not exceed 50m; otherwise, the minimum pressure at the end of the upper horizontal tunnel will not meet the requirement of not less than 2m head. The limitation on the extension length of the upper horizontal tunnel section for water diversion leads to a longer length for the middle and lower horizontal tunnel sections, which increase the internal water pressure, thus increasing the investment in pumped storage power stations.

[0005] The thickness of the overlying rock in the upper horizontal tunnel section of the water diversion tunnel does not meet the minimum overburden thickness requirement, leading to an increase in the area to which the steel lining needs to be installed. When the terrain behind the side intake and outlet of the upper reservoir is low and the geological conditions are poor, the thickness of the overlying rock in the upper horizontal tunnel section of the water diversion tunnel may not meet the minimum overburden thickness requirement due to the elevation limitations of the side intake and outlet. This necessitates the use of steel lining in the upper horizontal tunnel section immediately after the emergency maintenance gate of the upper reservoir intake and outlet. In addition, the tunnel diameter of the upper horizontal tunnel section is generally large, further increasing the project investment. On the other hand, since the steel lining installation in the upper horizontal section needs to be transported through the construction adit of the upper horizontal tunnel section during the construction period to meet the transportation requirements of the large-diameter pressure steel pipe in the upper horizontal tunnel section, the size of the construction adit of the upper horizontal tunnel section will also be large, further increasing the project investment.

[0006] Restricting the use of single-stage inclined shafts hinders the reduction of project investment and the realization of power plant benefits. Currently, most pumped storage power plants in China adopt a two-stage inclined shaft layout for their water intake systems. Due to the eccentric effect of directional drilling rigs, the length of the inclined shafts is mostly controlled at 300m to 400m. Considering the need for slag removal, the inclination angle of the inclined shafts is mostly 50° to 75°. For example, the No. 1 upper inclined shaft of the completed Changlongshan pumped storage power plant is 435m long, the longest among existing pumped storage power plants in China; the upper and lower inclined shafts of the Tiantai pumped storage power plant are 483.4m long, the longest among pumped storage power plants under construction in China. For most pumped storage power stations with an average head of around 400m to 500m, considering the impact of the suction height, if the upper reservoir's inlet and outlet are side-type, the length of its first-stage inclined shaft is generally 500m to 600m, exceeding the critical value for the technical difficulty of constructing a first-stage inclined shaft. When arranging the water diversion system, for construction safety considerations, two-stage inclined shafts or two-stage vertical shafts are used. This leads to the need to set up construction adits in the horizontal tunnel section between the two-stage inclined shafts or two-stage vertical shafts, thereby increasing the project investment. Furthermore, the two-stage inclined shafts or two-stage vertical shafts add two bends, resulting in increased head loss, which in turn affects the efficiency of the power station. Summary of the Invention

[0007] In view of the shortcomings of the prior art described above, the technical problem to be solved by the present invention is to provide a water diversion system and parameter determination method for a hydropower station that meets the pressure requirements of the upper flat tunnel section, which can better ensure that the minimum pressure head at the end of the upper flat tunnel section meets the design requirements, ensure the stable operation of the pumped storage power station, improve the efficiency of the pumped storage power station, shorten the construction period of the project, and reduce the project investment.

[0008] To solve the above-mentioned technical problems, the present invention provides a hydropower station water diversion system that meets the pressure requirements of the upper flat tunnel section, comprising:

[0009] Vertical well-type inlet and outlet of the upper reservoir;

[0010] The upper flat tunnel section has two ends along its own extension direction, namely the first end and the second end, and the first end of the upper flat tunnel section is connected to the vertical well inlet and outlet of the upper reservoir.

[0011] A first-stage inclined shaft, wherein the two ends of the first-stage inclined shaft along its own extension direction are an inclined top end and an inclined bottom end, and the inclined top end of the first-stage inclined shaft is connected to the second end of the upper horizontal tunnel section;

[0012] The lower horizontal tunnel section has two ends along its own extension direction, namely the first end and the second end, and the first end of the lower horizontal tunnel section is connected to the inclined bottom end of the first-stage inclined shaft;

[0013] The water diversion steel branch pipe has a front end, a rear end, and an upper end that are connected in pairs. The front end of the water diversion steel branch pipe is connected to the second end of the lower horizontal tunnel section, the rear end of the water diversion steel branch pipe is connected to the water diversion steel branch pipe, and the upper end of the water diversion steel branch pipe is connected to the drainage gallery of the lower horizontal tunnel section.

[0014] An underground powerhouse, which is connected to a water diversion steel branch pipe;

[0015] An underground factory exploration tunnel, located above the underground factory building;

[0016] The intermediate construction adit has an entrance and an end. The intermediate construction adit is connected to the underground powerhouse exploration tunnel and the lower half of the first-stage inclined shaft, and the end of the intermediate construction adit is connected to the inclined shaft drainage gallery.

[0017] Furthermore, the top of the vertical shaft-type inlet and outlet of the upper reservoir extends into the upper reservoir, and the bottom of the vertical shaft-type inlet and outlet of the upper reservoir is connected to the upper flat tunnel section.

[0018] Furthermore, the longitudinal slope of the upper flat tunnel section is 0% to 10%.

[0019] Furthermore, the inclination angle of the first-stage inclined shaft relative to the horizontal plane is 50° to 75°.

[0020] Furthermore, the lower horizontal tunnel section, the water diversion steel branch pipe, and the water diversion steel branch pipe are all flat-bottomed, and the longitudinal slope of the lower horizontal tunnel section, the water diversion steel branch pipe, and the water diversion steel branch pipe is all 0%.

[0021] Furthermore, the distance between the underground powerhouse exploratory tunnel and the top of the underground powerhouse is 40m to 50m;

[0022] Furthermore, the longitudinal slope of the intermediate construction adit is 0% to 10%.

[0023] Furthermore, the primary inclined shaft is divided into an upper inclined shaft section and a lower inclined shaft section by the intermediate construction adit, and the length of both the upper and lower inclined shaft sections is no more than 480m.

[0024] The present invention also provides a method for determining the parameters of a hydropower station water diversion system that meets the pressure requirements of the upper flat tunnel section, comprising the following steps:

[0025] Determine the minimum submergence depth of the vertical shaft inlet and outlet of the upper reservoir, and determine the top elevation of the vertical shaft inlet and outlet of the upper reservoir based on the minimum submergence depth;

[0026] Based on the design elevation of the ring road around the upper reservoir and the highest surge value of the emergency maintenance gate well at the inlet and outlet of the upper reservoir, the platform top elevation of the emergency maintenance gate well at the inlet and outlet of the upper reservoir is determined.

[0027] Based on the opening and closing rate and time requirements of the emergency maintenance gates at the inlet and outlet of the upper reservoir, the maximum height of the emergency maintenance gate well at the inlet and outlet of the upper reservoir is determined.

[0028] Based on the platform top elevation and maximum height requirements of the emergency maintenance gate well at the inlet and outlet of the upper reservoir, the minimum starting elevation of the upper horizontal tunnel section is determined, and the longitudinal slope of the upper horizontal tunnel section is adjusted within the range of 0% to 10% according to the length requirements of the first-level inclined shaft.

[0029] The elevations of the water diversion steel branch pipe, water diversion steel branch pipe, and lower horizontal tunnel section are determined sequentially based on the installation elevation of the underground powerhouse. The center elevation of the pressure steel pipe at the end of the water diversion steel branch pipe is consistent with the installation elevation of the underground powerhouse. The water diversion steel branch pipe, water diversion steel branch pipe, and pressure steel pipe of the lower horizontal tunnel section are all flat-bottomed, and the longitudinal slope of the water diversion steel branch pipe, water diversion steel branch pipe, and pressure steel pipe of the lower horizontal tunnel section is 0%.

[0030] The starting point of the lower horizontal tunnel section is taken as the end of the first-level inclined shaft. After determining the end position of the first-level inclined shaft, the first-level inclined shaft is arranged according to the inclination angle requirement of 50° to 75°. The inclined top of the first-level inclined shaft is connected to the end of the upper horizontal tunnel section.

[0031] The underground powerhouse exploration tunnel was extended to form a mid-level construction adit, which intersected with the first-level inclined shaft and divided the first-level inclined shaft into two sections.

[0032] Verify whether the lengths of the two sections of the first-stage inclined shaft do not exceed 480m, which is the current level of inclined shaft construction technology. If one section exceeds 480m, adjust the longitudinal slope of the middle construction adit to ensure that the lengths of the two sections of the first-stage inclined shaft are both less than 480m.

[0033] By calculating the hydraulic mechanical transition process, the minimum pressure head at the end of the upper tunnel section is checked to see if it is not less than 2m. If it meets the requirement, the layout of the hydropower station's water diversion system is completed. If it does not meet the requirement, the longitudinal slope of the upper tunnel section is increased and the emergency maintenance gate well of the upper reservoir's inlet and outlet is moved back for adjustment and verification until the minimum pressure head at the end of the upper tunnel section meets the requirement.

[0034] As described above, the hydropower station water diversion system and parameter determination method of the present invention, which meets the pressure requirements of the upper flat tunnel section, has the following beneficial effects: The hydropower station water diversion system of the present invention adopts the arrangement of vertical shaft inlet and outlet of the upper reservoir, which can make full use of the vertical shaft length of the vertical shaft inlet and outlet of the upper reservoir, reduce the elevation of the upper flat tunnel section, and ensure that the minimum initial pressure of the upper flat tunnel section is relatively large when the upper reservoir is at dead water level. This, in turn, can fully guarantee the minimum pressure head requirement of 2m at the end of the upper flat tunnel section when the pumping power is cut off, preventing water hammer and ensuring the safe and stable operation of the pumped storage power station's water transmission and power generation system. At the same time, using the vertical shaft length of the upper reservoir's vertical shaft inlet and outlet to reduce the elevation of the upper flat tunnel section can increase the surrounding rock thickness of the upper flat tunnel section, effectively reducing the range of the steel lining section of the water diversion system and reducing project investment. The upper flat tunnel section has a low elevation and a relatively large initial pressure, which... Extending the length of the upper horizontal tunnel section can shorten the length of the high-pressure steel pipe section of the lower horizontal tunnel section, reducing project investment; increasing the thickness of the surrounding rock in the upper horizontal tunnel section meets the minimum overburden criterion, allowing for the use of reinforced concrete lining throughout, avoiding the need for steel lining in the upper horizontal tunnel section, and reducing the cross-sectional size of the high-level construction adit, thus reducing project investment; the lower horizontal tunnel section adopts a flat-bottom design, facilitating drainage by the self-weight of water flow during maintenance; extending the underground powerhouse exploration tunnel to form a mid-level construction adit can save on construction adits in the mid-level tunnel section, reducing project investment; the 500m-class inclined shaft, which exceeds the existing inclined shaft construction technology level, can be divided into two sections, ensuring the construction safety of the first-stage inclined shaft, expanding the application range of the first-stage inclined shaft in pumped storage power stations with an average head of 400m to 500m, reducing the head loss at bends when using two-stage inclined shafts or two-stage vertical shafts, and improving the efficiency of pumped storage power stations. Therefore, the hydropower station water diversion system of the present invention can better ensure that the minimum pressure head at the end of the Shangpingdong section meets the design requirements, guarantee the stable operation of the pumped storage power station, improve the efficiency of the pumped storage power station, shorten the construction period of the project, and reduce the project investment. Attached Figure Description

[0035] Figure 1 The diagram shown is a cross-sectional view of the water diversion system of the hydropower station that meets the pressure requirements of the Shangpingdong section according to the present invention.

[0036] Figure 2 The diagram shown is a top view of the water diversion system of the hydropower station that meets the pressure requirements of the Shangpingdong section according to the present invention.

[0037] Component labeling descriptions: 1. Upper reservoir vertical shaft inlet / outlet; 2. Upper reservoir; 3. Upper reservoir ring road; 4. Reservoir inlet / outlet emergency maintenance gate well; 5. High-level construction adit; 6. Upper horizontal tunnel section; 7. First-stage inclined shaft; 8. Lower horizontal tunnel section; 9. Low-level construction adit; 10. Water diversion steel branch pipe; 11. Water diversion steel branch pipe; 12. Underground powerhouse; 13. Underground powerhouse exploration tunnel; 14. Mid-level construction adit; 15. Inclined shaft drainage gallery; 16. Lower horizontal tunnel drainage gallery. Detailed Implementation

[0038] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0039] It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings of this specification are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of the invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0040] like Figure 1 and Figure 2 As shown, the present invention provides a water diversion system for a hydropower station that meets the pressure requirements of the upper flat tunnel section, comprising:

[0041] Vertical well-type inlet and outlet of the upper reservoir 1;

[0042] Upper flat tunnel section 6, the two ends of the upper flat tunnel section 6 along its own extension direction are the first end and the second end, the first end of the upper flat tunnel section 6 is connected to the vertical well inlet / outlet 1 of the upper reservoir;

[0043] The first-stage inclined shaft 7 has an inclined top and an inclined bottom at its two ends along its own extension direction, and the inclined top of the first-stage inclined shaft 7 is connected to the second end of the upper horizontal tunnel section 6.

[0044] The lower horizontal tunnel section 8 has a first end and a second end at its two ends along its own extension direction, and the first end of the lower horizontal tunnel section 8 is connected to the inclined bottom end of the first-stage inclined shaft 7.

[0045] The water diversion steel branch pipe 10 has a front end, a rear end, and an upper end that are connected in pairs. The front end of the water diversion steel branch pipe 10 is connected to the second end of the lower horizontal tunnel section 8, the rear end of the water diversion steel branch pipe 10 is connected to the water diversion steel branch pipe 11, and the upper end of the water diversion steel branch pipe 10 is connected to the drainage gallery 16 of the lower horizontal tunnel section.

[0046] The underground powerhouse 12 is connected to the water diversion steel branch pipe 11;

[0047] The underground powerhouse exploration tunnel 13 is located above the underground powerhouse 12;

[0048] The intermediate construction adit 14 has an entrance and an end. The intermediate construction adit 14 is connected to the underground powerhouse exploration tunnel 13 and the lower half of the first-stage inclined shaft 7, and the end of the intermediate construction adit 14 is connected to the inclined shaft drainage gallery 15.

[0049] In the hydropower station water diversion system of the present invention, the vertical shaft inlet / outlet 1 of the upper reservoir is used to pump water from an upper reservoir 2 or to discharge water into the upper reservoir 2. The upper horizontal tunnel section 6 has a first end and a second end at its two ends along its extension direction, the first end generally referred to as the starting point and the second end generally referred to as the ending point. The first-stage inclined shaft 7 has an inclined top end and an inclined bottom end at its two ends along its extension direction, the inclined top end generally referred to as the starting point and the inclined bottom end generally referred to as the ending point. The lower horizontal tunnel section 8 has a first end and a second end at its two ends along its extension direction, the first end generally referred to as the starting point and the second end generally referred to as the ending point.

[0050] The hydropower station water diversion system of this invention adopts the arrangement of vertical shaft inlet and outlet 1 of the upper reservoir. This fully utilizes the length of the vertical shaft inlet and outlet 1, reducing the elevation of the upper horizontal tunnel section 6. This ensures a higher minimum initial pressure for the upper horizontal tunnel section 6 when the upper reservoir 2 is at a dead water level. Consequently, it effectively guarantees the minimum pressure head requirement of 2m at the end of the upper horizontal tunnel section 6 when the pumping operation is interrupted (see the "Design Code for Hydraulic Tunnels" (NB / T10391—2020)). This prevents water hammer and ensures the safe and stable operation of the pumped storage power station's water conveyance and power generation system. Simultaneously, utilizing the length of the vertical shaft inlet and outlet 1 of the upper reservoir to reduce the elevation of the upper horizontal tunnel section 6 increases the surrounding rock thickness, effectively reducing the range of the steel lining section of the water diversion system and lowering project investment. The lower elevation and higher initial pressure of the upper horizontal tunnel section 6 effectively extend the upper horizontal tunnel. The length of section 6 can shorten the length of the high-pressure steel pipe section of the lower horizontal tunnel section 8, reducing project investment; the increased thickness of the surrounding rock in the upper horizontal tunnel section 6 meets the minimum overburden criterion, allowing for the use of reinforced concrete lining throughout, avoiding the need for steel lining in the upper horizontal tunnel section 6, which can reduce the cross-sectional size of the high-level construction adit 5, further reducing project investment; the lower horizontal tunnel section 8 adopts a flat bottom design, facilitating drainage by the self-weight of water flow during maintenance; the underground powerhouse exploration tunnel 13 is extended to form the intermediate construction adit 14, saving on the construction adit of the intermediate horizontal tunnel section, reducing project investment, and dividing the 500m-class inclined shaft, which exceeds the existing inclined shaft construction technology level, into two sections, ensuring the construction safety of the first-stage inclined shaft 7, expanding the application range of the first-stage inclined shaft 7 in pumped storage power stations with an average head of 400m to 500m, reducing the head loss at bends when using two-stage inclined shafts or two-stage vertical shafts, and improving the efficiency of pumped storage power stations.

[0051] Therefore, the hydropower station water diversion system of the present invention can better ensure that the minimum pressure head at the end of the Shangpingdong section meets the design requirements, guarantee the stable operation of the pumped storage power station, improve the efficiency of the pumped storage power station, shorten the construction period of the project, and reduce the project investment.

[0052] Furthermore, the water diversion system of the hydropower station can be arranged in a parallel manner to improve operational efficiency. For example, there are two vertical shaft inlets and outlets 1 in the upper reservoir, two upper horizontal tunnel sections 6, two first-stage inclined shafts 7, two lower horizontal tunnel sections 8, and two water diversion steel branch pipes 10. Each water diversion steel branch pipe 10 is connected to the underground powerhouse 12 through two water diversion steel branch pipes 11.

[0053] Furthermore, the end of the intermediate construction adit 14 is connected to the first-stage inclined shaft 7, and the starting point (i.e. the initial end) of the intermediate construction adit 14 is connected to the underground powerhouse exploration tunnel 13. With this arrangement, the extension length of the underground powerhouse exploration tunnel 13 can be used to shorten the length of the intermediate construction adit 14 itself, reduce the investment in construction auxiliary facilities, shorten the construction period of the first-stage inclined shaft 7, and ensure the construction reliability of the first-stage inclined shaft 7.

[0054] Furthermore, the end of the intermediate construction adit 14 is provided with an inclined shaft drainage gallery 15, the upstream end of which exceeds the first-stage inclined shaft 7, which can reduce the external water pressure of the pressure steel pipe in the middle of the first-stage inclined shaft 7.

[0055] Furthermore, the longitudinal slope of the intermediate construction adit 14 is 0% to 10%, which can be adjusted according to the segment length requirements of the first-stage inclined shaft 7 to improve the adjustability of the segment position of the first-stage inclined shaft 7.

[0056] Furthermore, a lower horizontal tunnel drainage corridor 16 is provided above the lower horizontal tunnel section 8, and the upstream end of the lower horizontal tunnel drainage corridor 16 exceeds the first-level inclined shaft 7. The lower horizontal tunnel drainage corridor 16 can reduce the external water pressure in the lower part of the first-level inclined shaft 7, the lower horizontal tunnel section 8, the water diversion steel branch pipe 10, and the water diversion steel branch pipe 11.

[0057] Furthermore, a low-level construction adit 9 is arranged on the lower horizontal tunnel section 8, and the lower horizontal tunnel section 8, the water diversion steel branch pipe 10, and the water diversion steel branch pipe 11 are all arranged with a flat bottom to facilitate drainage by their own weight during maintenance.

[0058] Furthermore, the upper flat tunnel section 6 is equipped with an emergency maintenance gate well 4 for the reservoir inlet and outlet and an elevated construction adit 5.

[0059] Furthermore, the longitudinal slope of the upper horizontal tunnel section 6 is 0% to 10%. It can be adjusted in conjunction with the minimum pressure head requirement of not less than 2m at the end of the upper horizontal tunnel section 6.

[0060] Furthermore, the top of the emergency maintenance gate well 5 at the inlet and outlet of the upper reservoir is connected to the reservoir ring road 3. The emergency maintenance gate well 5 at the inlet and outlet of the upper reservoir also serves as a water diversion and pressure regulating chamber.

[0061] Furthermore, the distance between the high-level construction adit 5 and the emergency maintenance gate well 5 at the inlet and outlet of the upper reservoir is 30m to 45m.

[0062] Furthermore, the longitudinal slope of the elevated construction adit 5 is 0% to 8%.

[0063] Furthermore, the vertical height of the upper reservoir's vertical well-type inlet / outlet 1 is 50m to 80m.

[0064] Furthermore, the top of the vertical well-type inlet / outlet 1 of the upper reservoir extends into the upper reservoir 2, and the bottom of the vertical well-type inlet / outlet 1 of the upper reservoir is connected to the upper flat tunnel section 6.

[0065] Furthermore, the inclination angle of the first-stage inclined shaft 7 relative to the horizontal plane is 50° to 75°, which is greater than the angle of repose of the rock block. The self-weight of the excavated rock block can be used to remove slag from the first-stage inclined shaft 7.

[0066] Furthermore, in order to facilitate drainage by the weight of water during maintenance, the lower horizontal tunnel section 8, the water diversion steel branch pipe 10, and the water diversion steel branch pipe 11 are all flat-bottomed, and the longitudinal slope of the lower horizontal tunnel section 8, the water diversion steel branch pipe 10, and the water diversion steel branch pipe 11 is all 0%.

[0067] Furthermore, the distance between the underground powerhouse exploratory tunnel 13 and the top of the underground powerhouse 12 is 40m to 50m;

[0068] Furthermore, the first-stage inclined shaft 7 is divided into an upper inclined shaft section and a lower inclined shaft section by the intermediate construction adit 14, and the length of both the upper and lower inclined shaft sections is no more than 480m.

[0069] The present invention also provides a method for determining the parameters of a hydropower station water diversion system that meets the pressure requirements of the upper flat tunnel section, comprising the following steps:

[0070] Determine the minimum submergence depth of the vertical shaft inlet / outlet 1 of the upper reservoir, and determine the top elevation of the vertical shaft inlet / outlet 1 of the upper reservoir based on the minimum submergence depth;

[0071] Based on the design elevation of the upper reservoir ring road 3 and the highest surge value of the upper reservoir inlet and outlet emergency maintenance gate well 4, the platform top elevation of the upper reservoir inlet and outlet emergency maintenance gate well 4 is determined.

[0072] Based on the opening and closing rate and time requirements of the emergency maintenance gates at the inlet and outlet of the upper reservoir, the maximum height of the emergency maintenance gate well 4 at the inlet and outlet of the upper reservoir is determined.

[0073] Based on the platform top elevation and maximum height requirements of the emergency maintenance gate well 4 at the inlet and outlet of the upper reservoir, the minimum starting elevation of the upper horizontal tunnel section 6 is determined, and the longitudinal slope of the upper horizontal tunnel section 6 is adjusted within the range of 0% to 10% according to the length requirements of the first-level inclined shaft 7.

[0074] Based on the installation elevation of the underground powerhouse 12, the elevations of the water diversion steel branch pipe 11, the water diversion steel branch pipe 10, and the lower horizontal tunnel section 8 are determined sequentially. The center elevation of the pressure steel pipe at the end of the water diversion steel branch pipe 11 is consistent with the installation elevation of the underground powerhouse 12. The water diversion steel branch pipe 11, the water diversion steel branch pipe 10, and the pressure steel pipe of the lower horizontal tunnel section 8 are all flat-bottomed, and the longitudinal slope of the water diversion steel branch pipe 11, the water diversion steel branch pipe 10, and the pressure steel pipe of the lower horizontal tunnel section 8 are all 0%.

[0075] The starting point of the lower horizontal tunnel section 8 is taken as the end of the first-level inclined shaft 7. After determining the end position of the first-level inclined shaft 7, the first-level inclined shaft 7 is arranged according to the inclination angle requirement of 50° to 75°. The inclined top of the first-level inclined shaft 7 is connected to the end of the upper horizontal tunnel section 6.

[0076] The underground powerhouse exploration tunnel 13 is extended to form a mid-level construction adit 14, which intersects with the first-stage inclined shaft 7 and divides the first-stage inclined shaft 7 into two sections.

[0077] Verify whether the lengths of the two sections of the first-stage inclined shaft 7 do not exceed 480m, which is the current level of inclined shaft construction technology. If one section exceeds 480m, adjust the longitudinal slope of the middle construction adit 14 to ensure that the lengths of the two sections of the first-stage inclined shaft 7 are both less than 480m.

[0078] By calculating the hydraulic mechanical transition process, the minimum pressure head at the end of the upper horizontal tunnel section 6 is checked to see if it is not less than 2m. If it meets the requirements, the layout of the hydropower station's water diversion system is completed. If it does not meet the requirements, the longitudinal slope of the upper horizontal tunnel section 6 is increased (up to 10%) and the emergency maintenance gate well 4 of the upper reservoir inlet and outlet is moved backward for adjustment and verification until the minimum pressure head at the end of the upper horizontal tunnel section 6 meets the requirements.

[0079] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0080] The design of the vertical shaft inlet and outlet of the upper reservoir combined with the layout of the upper horizontal tunnel section in this invention can fully utilize the length of the vertical shaft of the upper reservoir inlet and outlet, reduce the elevation of the upper horizontal tunnel section, and ensure a larger minimum initial pressure in the upper horizontal tunnel section when the upper reservoir is at a dead water level. This, in turn, can fully guarantee the minimum pressure head requirement of 2m at the end of the upper horizontal tunnel section when the pumping operation is interrupted, preventing water hammer and ensuring the safe and stable operation of the pumped storage power station's water conveyance and power generation system. Simultaneously, by utilizing the length of the vertical shaft of the upper reservoir inlet and outlet... Lowering the elevation of the upper tunnel section increases the thickness of the surrounding rock, effectively reducing the scope of the steel lining section of the water diversion system and lowering project investment. The lower elevation and higher initial pressure of the upper tunnel section effectively extend its length, thereby shortening the length of the high-pressure steel pipe section of the lower tunnel section and further reducing project investment. The increased thickness of the surrounding rock in the upper tunnel section meets the minimum overburden criterion, allowing for the use of reinforced concrete lining throughout, eliminating the need for steel lining in the upper tunnel section, reducing the cross-sectional dimensions of the high-level construction adit and lowering project investment.

[0081] The flat-bottomed arrangement of the lower tunnel section, water diversion steel branch pipe, and water diversion steel branch pipe section in this invention allows for drainage of the lower tunnel section, water diversion steel branch pipe, and water diversion steel branch pipe section by the weight of the water flow during maintenance, avoiding the use of water pumps for drainage. This can effectively reduce the maintenance costs during the operation of the pumped storage power station and improve the efficiency of the power station.

[0082] In this invention, the underground powerhouse exploration tunnel is extended into a mid-level construction adit, and the mid-level construction adit is arranged in the lower part of the first-level inclined shaft, intersecting with the first-level inclined shaft. This arrangement can save on the construction adit of the mid-level horizontal tunnel, reduce project investment, and divide the 500m-class inclined shaft, which exceeds the existing inclined shaft construction technology level, into two sections. This ensures the construction safety and reliability of the first-level inclined shaft, expands the application range of the first-level inclined shaft in pumped storage power stations with an average head of 400m to 500m, reduces the head loss at bends when using two-level inclined shafts or two-level vertical shafts, and improves the efficiency of pumped storage power stations.

[0083] In summary, this invention can better ensure that the minimum pressure head at the end of the upper-level tunnel section meets the design requirements, guarantee the stable operation of the pumped storage power station, improve the efficiency of the pumped storage power station, shorten the construction period, and reduce project investment. Therefore, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0084] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A water diversion system for a hydropower station that meets the pressure requirements of the upper level tunnel section, characterized in that, include: Vertical well-type inlet and outlet of the upper reservoir (1); Upper flat tunnel section (6), the two ends of the upper flat tunnel section (6) along its own extension direction are the first end and the second end, the first end of the upper flat tunnel section (6) is connected to the vertical well inlet and outlet of the upper reservoir (1); The first-stage inclined shaft (7) has an inclined top and an inclined bottom at its two ends along its own extension direction, and the inclined top of the first-stage inclined shaft (7) is connected to the second end of the upper horizontal tunnel section (6). The lower horizontal tunnel section (8) has two ends along its own extension direction, namely the first end and the second end, and the first end of the lower horizontal tunnel section (8) is connected to the inclined bottom end of the first-stage inclined shaft (7). Water diversion steel branch pipe (10) has a front end, a rear end and an upper end that are connected in pairs. The front end of the water diversion steel branch pipe (10) is connected to the second end of the lower horizontal tunnel section (8). The rear end of the water diversion steel branch pipe (10) is connected to the water diversion steel branch pipe (11). The upper end of the water diversion steel branch pipe (10) is connected to the drainage gallery (16) of the lower horizontal tunnel section. An underground powerhouse (12) is connected to a water diversion steel branch pipe (11); An underground plant exploration tunnel (13) is located above the underground plant (12); The intermediate construction adit (14) has an opening and an end. The intermediate construction adit (14) is connected to the underground powerhouse exploration tunnel (13) and the lower half of the first-stage inclined shaft (7), and the end of the intermediate construction adit (14) is connected to the inclined shaft drainage gallery (15).

2. The hydropower station water diversion system that meets the pressure requirements of the upper flat tunnel section according to claim 1, characterized in that: The top of the vertical well-type inlet / outlet (1) of the upper reservoir extends into the upper reservoir (2), and the bottom of the vertical well-type inlet / outlet (1) of the upper reservoir is connected to the upper flat tunnel section (6).

3. The hydropower station water diversion system that meets the pressure requirements of the upper flat tunnel section according to claim 2, characterized in that: The longitudinal slope of the upper flat tunnel section (6) is 0% to 10%.

4. The hydropower station water diversion system that meets the pressure requirements of the upper flat tunnel section according to claim 1, characterized in that: The first-stage inclined shaft (7) has an inclination angle of 50° to 75° relative to the horizontal plane.

5. The hydropower station water diversion system that meets the pressure requirements of the upper tunnel section according to claim 1, characterized in that: The lower horizontal tunnel section (8), the water diversion steel branch pipe (10), and the water diversion steel branch pipe (11) are all flat-bottomed, and the longitudinal slope of the lower horizontal tunnel section (8), the water diversion steel branch pipe (10), and the water diversion steel branch pipe (11) is 0%.

6. The hydropower station water diversion system that meets the pressure requirements of the upper tunnel section according to claim 1, characterized in that: The distance between the underground plant exploration tunnel (13) and the top of the underground plant (12) is 40m to 50m.

7. The hydropower station water diversion system that meets the pressure requirements of the upper tunnel section according to claim 1, characterized in that: The longitudinal slope of the intermediate construction adit (14) is 0% to 10%.

8. The hydropower station water diversion system that meets the pressure requirements of the upper flat tunnel section according to claim 7, characterized in that: The first-stage inclined shaft (7) is divided into an upper inclined shaft section and a lower inclined shaft section by the middle construction adit (14). The length of the upper inclined shaft section and the length of the lower inclined shaft section are both no more than 480m.

9. A method for determining parameters of a hydropower station's water diversion system that meets the pressure requirements of the upper tunnel section, as described in any one of claims 1 to 8, characterized in that... The steps include the following: Determine the minimum submergence depth of the vertical shaft inlet and outlet (1) of the upper reservoir, and determine the top elevation of the vertical shaft inlet and outlet (1) of the upper reservoir based on the minimum submergence depth; Based on the design elevation of the upper reservoir ring road (3) and the highest surge value of the upper reservoir inlet and outlet accident maintenance gate well (4), the platform top elevation of the upper reservoir inlet and outlet accident maintenance gate well (4) is determined. Based on the opening and closing rate and time requirements of the emergency maintenance gates at the inlet and outlet of the upper reservoir, the maximum height of the emergency maintenance gate well (4) at the inlet and outlet of the upper reservoir is determined. Based on the platform top elevation and maximum height requirements of the emergency maintenance gate well (4) at the inlet and outlet of the upper reservoir, the minimum elevation of the starting point of the upper horizontal tunnel section (6) is determined, and the longitudinal slope of the upper horizontal tunnel section (6) is adjusted within the range of 0% to 10% according to the length requirements of the first-level inclined shaft (7). The elevations of the water diversion steel branch pipe (11), water diversion steel branch pipe (10), and lower horizontal tunnel section (8) are determined sequentially based on the installation elevation of the underground powerhouse (12). The center elevation of the pressure steel pipe at the end of the water diversion steel branch pipe (11) is consistent with the installation elevation of the underground powerhouse (12). The pressure steel pipes of the water diversion steel branch pipe (11), water diversion steel branch pipe (10), and lower horizontal tunnel section (8) are all flat-bottomed, and the longitudinal slopes of the pressure steel pipes of the water diversion steel branch pipe (11), water diversion steel branch pipe (10), and lower horizontal tunnel section (8) are all 0%. The starting point of the lower horizontal tunnel section (8) is taken as the end of the first-level inclined shaft (7). After determining the end position of the first-level inclined shaft (7), the first-level inclined shaft (7) is arranged according to the inclination angle requirement of 50° to 75°. The inclined top of the first-level inclined shaft (7) is connected to the end of the upper horizontal tunnel section (6). The underground plant exploration tunnel (13) is extended to form a mid-level construction adit (14), which intersects with the first-level inclined shaft (7) and divides the first-level inclined shaft (7) into two sections. Verify whether the lengths of the two sections of the first-level inclined shaft (7) do not exceed 480m, which is the current level of inclined shaft construction technology. If one section exceeds 480m, adjust the longitudinal slope of the middle construction adit (14) to ensure that the lengths of the two sections of the first-level inclined shaft (7) are less than 480m. By calculating the hydraulic mechanical transition process, check whether the minimum pressure head at the end of the upper flat tunnel section (6) is not less than 2m. If the requirement is met, the arrangement of the hydropower station's water diversion system is completed. If the requirement is not met, adjust and check by increasing the longitudinal slope of the upper flat tunnel section (6) and moving the emergency maintenance gate well (4) of the upper reservoir inlet and outlet until the minimum pressure head at the end of the upper flat tunnel section (6) meets the requirement.

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