A vertical shaft spillway structure with wall detachment and construction diversion

Abstract

The application discloses a kind of wall detachment flow shaft-type spillway structures giving consideration to construction diversion, including annular overflow weir, shaft body section, sudden expansion section, air vent, stilling well, diversion tunnel, plug, air pressure plate, baffle, non-pressure tunnel and downstream energy dissipation facility.No gate is set on the weir top of annular overflow weir, sudden expansion section is arranged at the shaft inlet, air vent is arranged around sudden expansion section and is communicated with atmosphere, so that the water flow is formed into wall detachment flow state in the shaft body section;stilling well is arranged at the bottom of shaft, air pressure plate is arranged at the connecting section of stilling well and non-pressure tunnel;diversion tunnel is arranged on the upstream side of shaft and is connected with shaft perpendicularly, baffle is arranged at the connecting interface, plug is arranged in diversion tunnel on the upstream side of shaft during operation period, and the downstream section is converted into permanent flood discharge channel.The construction diversion tunnel and permanent shaft-type spillway are integrated in the application, the excavation and lining engineering quantity is reduced, the risk of cavitation damage of high-speed water flow to shaft wall is eliminated, and the safety of whole-process flood discharge is ensured.

Description

Technical Field

[0001] This invention relates to the field of flood discharge structures in water conservancy and hydropower projects, and in particular to a vertical shaft-type spillway structure that also serves as a construction diversion mechanism. Background Technology

[0002] The safety of flood discharge in pumped storage power stations is crucial for ensuring the stable operation of the station and the safety of the dam and downstream areas. Among various flood discharge facilities, vertical shaft spillways have been widely used in hydropower projects due to their high safety, small footprint, and ability to fully utilize internal space for energy dissipation. However, traditional vertical shaft spillways and construction diversion tunnels are often constructed independently, resulting in large-scale projects, high investment costs, and significant construction time and space requirements. Furthermore, conventional vertical shaft flood discharge methods are susceptible to cavitation damage under high-speed water flow, posing long-term safety hazards. Additionally, the connection between the stilling well and the downstream unpressurized tunnel often experiences severe water surface fluctuations and alternating open and full flow, seriously affecting the operational reliability of the flood discharge tunnel.

[0003] Drop shafts possess advantages such as simple structure, high energy dissipation rate, and low impact from water flow atomization. They can adapt to complex terrain and geological conditions and are considered environmentally friendly flood discharge and energy dissipation structures. A drop shaft flood discharge tunnel mainly consists of an annular overflow weir, a shaft section, a stilling well, a lower horizontal tunnel, a spillway, and a stilling basin. After overflowing through the annular overflow weir, the water flows into the shaft section through a gradually contracting transition section, continuously accelerating during its vertical descent. Upon entering the stilling well, the water is resisted at the bottom and rebounds, colliding and mixing with the downstream flow to form a undulating annular hydraulic jump, where the kinetic energy is fully dissipated. The water, after energy dissipation in the stilling well, flows through a pressureless tunnel and spillway into the downstream stilling basin, completing the final energy dissipation and scour prevention. However, because drop shafts are a relatively new type of structure, their engineering application and research started relatively late, and previous research results are still incomplete, especially in areas such as permanent and temporary combined layout, well wall cavitation protection, and downstream flow stability control, where technical bottlenecks remain.

[0004] Therefore, how to organically combine the construction diversion tunnel with the permanent flood discharge facilities under the premise of ensuring flood discharge safety, so as to achieve an integrated layout of permanent and temporary facilities, thereby minimizing project costs and shortening the construction period, while eliminating the risk of cavitation damage to the well wall by high-speed water flow and ensuring the stability of the flow pattern throughout the entire process from the vertical shaft inlet to the downstream energy dissipation facility, has become an important technical direction that needs to be broken through in the current hydropower engineering design. Summary of the Invention

[0005] The technical problem this invention aims to solve is to overcome the large engineering workload, high investment, and significant environmental damage caused by the independent arrangement of existing vertical shaft spillways and construction diversion tunnels, as well as the safety issues arising from the risks of well wall cavitation damage and downstream flow instability in conventional vertical shaft flood discharge methods. Based on a full consideration of the diversion requirements during construction, the safety of permanent flood discharge, and the structural stability during operation, this invention provides a simple, economical, safe, and effective permanent-temporary combined vertical shaft spillway structure. This structure organically combines the construction diversion tunnel with the permanent vertical shaft spillway, significantly reducing excavation and concrete lining work, minimizing environmental damage, eliminating the risk of cavitation damage to the well wall from high-speed water flow, and ensuring flood discharge safety and flow stability throughout the entire process from the shaft inlet to the downstream energy dissipation facility.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a vertical shaft spillway structure that also considers construction diversion, comprising: An annular overflow weir is located at the inlet of the vertical shaft, with no gate on the weir crest; The shaft section is connected below the annular overflow weir; The sudden expansion section is set at the connection between the annular overflow weir and the vertical shaft section, and is used to make the downstream water flow form a wall-detached flow state in the vertical shaft section where the water flow separates from the shaft wall. Ventilation holes are arranged around the sudden expansion section and are open to the atmosphere to replenish air into the vertical shaft to maintain the stability of the detachment flow cavity; A stilling well is provided at the bottom of the shaft section; A diversion tunnel is located on the upstream side of the vertical shaft section, and the downstream section of the diversion tunnel also serves as a permanent flood discharge channel. A pressureless tunnel connects the downstream section of the stilling well and the diversion tunnel; A plug is installed in the diversion tunnel on the upstream side of the vertical shaft section to seal the upstream section of the diversion tunnel during operation; Air pressure plates are installed at the connection section between the stilling well and the unpressurized tunnel to suppress water surface fluctuations; A flow deflector is installed at the connection interface between the vertical shaft section and the guide tunnel to guide the downstream water flow to form a rotating flow pattern. And sequentially connected downstream of the unpressurized tunnel are the vent, stilling basin, apron, and seawall.

[0007] Furthermore, the annular overflow weir is a practical annular weir; the sudden expansion section utilizes the combined effect of sudden expansion separation and centripetal aggregation of the vertical shaft annular overflow to form a three-layer "air-water-air" flow pattern within the vertical shaft section.

[0008] Furthermore, the energy dissipation well has a circular cross-section, and no energy dissipation structures are installed on the well wall.

[0009] Furthermore, there are multiple vent holes arranged circumferentially along the expansion section.

[0010] Furthermore, the air-compressing plate is a transverse convex structure with a trapezoidal cross section, and is located at the bottom of the connection section between the stilling well and the unpressurized tunnel.

[0011] Furthermore, the shaft section is perpendicularly connected to the diversion tunnel. During the construction period, the diversion tunnel undertakes the task of diverting water. During the operation period, the upstream section of the diversion tunnel is sealed by the plug, and the downstream section of the diversion tunnel is converted into a permanent flood discharge channel.

[0012] Furthermore, the flow deflector has an arc-shaped cross-section structure and is arranged along the circumference of the flow guide tunnel at the interface between the vertical shaft section and the flow guide tunnel.

[0013] Furthermore, the discharge channel is a steep channel, and the stilling basin is a bottom flow stilling basin.

[0014] Furthermore, the feature is that the diameter and number of the vent holes are configured such that the maximum wind speed of the vent holes is less than 60m / s under each operating condition.

[0015] Furthermore, the inner diameter of the crest of the annular overflow weir is 8–15 m, the inner diameter of the bottom is 5–10 m, and the height is 5–12 m; the depth of the shaft section is 80–120 m; the diameter of the vent holes is 30–60 cm, and the number is 3–6; the depth of the stilling well is 5–15 m; and the cross-section of the pressureless tunnel is a city gate type.

[0016] The beneficial effects of this invention are as follows: Based on full consideration of flood discharge safety, diversion requirements during construction, and structural stability during operation, it provides a simple, economical, safe, and effective permanent-temporary integrated vertical shaft spillway structure and its layout scheme. This structure is well-suited for pumped-storage power stations and conventional hydropower projects equipped with vertical shaft spillways and diversion tunnels, achieving a permanent-temporary integrated layout of the diversion tunnel and vertical shaft spillway, significantly reducing excavation and concrete lining work. By establishing a stable detached flow state through a sudden expansion section and ventilation holes at the shaft inlet, the risk of cavitation damage to the shaft wall from high-speed water flow is eliminated. By utilizing the energy dissipation through swirling mixing in the stilling well at the bottom of the shaft and the automatic aeration by the air-pressurized plate at the inlet of the unpressurized tunnel, violent water surface fluctuations are suppressed, ensuring stable open flow throughout the unpressurized tunnel. Furthermore, the combined energy dissipation and scour prevention through the downstream spillway, stilling basin, apron, and apron ensures full-process flood discharge safety. This provides design ideas and references for the design of vertical shaft spillways in similar projects and has significant reference value. Attached Figure Description

[0017] Figure 1 This is a longitudinal cross-sectional schematic diagram of the vertical shaft spillway structure for detached flow that also takes into account construction diversion in this invention. Figure 2 This is a schematic diagram of the shaft inlet. Figure 3 for Figure 2 Sectional view of AA in the middle; Figure 4 for Figure 2 Cross-sectional view of the middle section (BB); Figure 5 for Figure 1 CC section view; Figure 6 for Figure 1 Cross-sectional view of DD in the middle; Figure 7 for Figure 1 EE cross-section; Figure 8 for Figure 1 Cross-sectional view of FF in the middle; Figure 9 for Figure 1 Cross-sectional view of GG in China; Figure 10 This is a longitudinal section view of the swirl initiation section of the diversion tunnel; Figure 11 Plan view of the swirl initiation section of the diversion tunnel; Figure 12 This is a three-dimensional schematic diagram of the flow deflector. In the diagram, 1—annular overflow weir; 2—sudden expansion section; 3—vertical shaft section; 4—stilling well; 5—vent hole; 6—air pressure plate; 7—diversion tunnel; 8—plug; 9—baffle; 10—unpressurized tunnel; 11—venting channel; 12—stilling pool; 13—apron; 14—seawall. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0019] In the description of this invention, it should be noted that the terms "upper", "middle", "lower", "inner", "outer", "both sides", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the purpose of simplifying the description of this invention 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, they should not be construed as limiting this invention.

[0020] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0021] like Figure 1-12 As shown, the present invention, which incorporates a vertical shaft spillway structure for construction diversion, includes: an annular overflow weir 1, a sudden expansion section 2, a vertical shaft section 3, a stilling basin 4, vents 5, a pressure plate 6, a diversion tunnel 7, a plug 8, a deflector 9, a pressure-free tunnel 10, a spillway 11, a stilling basin 12, a retaining wall 13, and a seawall 14. Its key feature is that the permanent flood discharge structure adopts a vertical shaft spillway, with the inlet arranged as an annular practical weir 1, without a gate on the weir crest; a sudden expansion section 2 is provided at the shaft inlet, with vents 5 arranged around the sudden expansion section 2, the vents 5 communicating with the atmosphere, allowing the downstream water flow to form a stable detached flow state in the vertical shaft section 3 through the sudden expansion section 2 and the vents 5; the bottom of the vertical shaft... A stilling well 4 is installed. After the water jet from the detached wall falls into the stilling well 4, it dissipates energy through swirling and mixing. Then it connects vertically to the unpressurized tunnel 10. A compressed air plate 6 is installed at the connection section between the stilling well 4 and the unpressurized tunnel 10. The water flow after energy dissipation in the stilling well 4 enters the unpressurized tunnel 10, the spillway 11, the stilling basin 12, the apron 13, and the seawall 14 in sequence to complete the downstream energy dissipation and scour prevention. The temporary structure diversion tunnel 7 is arranged on the upstream side of the vertical shaft. The interface between the vertical shaft and the diversion tunnel is connected by a vertical shaft swirling flow method, and a flow deflector 9 is set to adjust the flow pattern of the downstream water flow. During the construction period, the diversion tunnel 7 undertakes all the diversion tasks. During the operation period, a plug 8 is installed in the diversion tunnel on the upstream side of the vertical shaft to seal it, and the downstream section is converted into a permanent flood discharge channel.

[0022] The annular overflow weir 1 adopts a practical annular weir with no gate on the weir crest, strong flow capacity, and simple structure.

[0023] The sudden expansion section 2 is located at the inlet of the shaft. By utilizing the sudden expansion separation and the centripetal aggregation effect of the shaft's annular overflow, the discharged water flow forms a stable "air-water-air" three-layer detached flow state in the shaft body section 3. The water flow is completely separated from the shaft wall, thereby avoiding the direct scouring of the shaft wall by high-speed water flow and eliminating the risk of cavitation damage.

[0024] The stilling well 4 has a circular cross-section. After the water jet from the detached wall falls into the stilling well 4, it forms a strongly mixed annular hydraulic jump, consuming most of the energy through internal swirling and mixing. No energy dissipation structures are required on the well wall, making the structure simple and easy to construct. The interface between the vertical shaft and the diversion tunnel 7 is connected using a vertical shaft vortex flow method, causing the downstream water flow to form a rotating flow pattern within the vertical shaft before entering the bottom stilling well 4.

[0025] Ventilation holes 5 are arranged around the sudden expansion section 2 at the shaft inlet, communicating with the atmosphere to replenish air into the shaft, maintain the stability of the detachment flow cavity, and prevent cavity collapse. For example... Figure 2 As shown, vents 5 are arranged around the shaft inlet. The diameter and number of vents 5 are determined according to the ventilation requirements to ensure that the maximum wind speed of the vents is below the specification limit of 60m / s under all operating conditions.

[0026] The air-compressing plate 6 adopts a trapezoidal cross-section transverse convex structure and is set at the connection section between the stilling well 4 and the unpressurized tunnel 10. It uses the kinetic energy of the water flow itself to entrain air, suppressing the violent water surface fluctuations caused when the water from the stilling well 4 enters the unpressurized tunnel 10, eliminating the phenomenon of water rushing over and alternating open and full flow, and ensuring that the unpressurized tunnel 10 maintains a stable open flow throughout. The height and spacing of the air-compressing plate 6 are determined according to the water flow conditions, with the goal of effectively suppressing water surface fluctuations and eliminating the alternation of open and full flow.

[0027] During operation, diversion tunnel 7 only requires sealing with a short plug 8 on the upstream side of the shaft. The plug 8 is made of concrete and is easy to construct. The plug 8 is installed inside the diversion tunnel on the upstream side of the shaft. During construction, diversion tunnel 7 undertakes all diversion tasks. During operation, the upstream section is sealed by the plug 8, and the downstream section is converted into a permanent flood discharge channel, realizing a shared channel for diversion and flood discharge.

[0028] The deflector 9 is located at the vortex connection interface between the vertical shaft and the diversion tunnel 7. It features an arc-shaped cross-section and is arranged circumferentially along the vertical shaft section 3. This design guides the downstream water flow to form a stable swirling flow pattern upon entering the vertical shaft section 3, enhancing the swirling mixing effect within the stilling well 4. The structure of the diversion tunnel's swirling section and the arrangement of the deflector are as follows: Figure 10 and Figure 11 As shown, the three-dimensional schematic diagram of the flow deflector is as follows: Figure 12 As shown The unpressurized tunnel 10 is shared with the downstream section of the diversion tunnel 7. After energy dissipation by the stilling well 4, the water flow remains in a stable open flow state within the unpressurized tunnel 10. The cross-sectional dimensions of the unpressurized tunnel 10 are determined based on the discharge capacity to ensure sufficient clearance at the tunnel top under various operating conditions.

[0029] The spillway 11 is located between the outlet of the unpressurized tunnel 10 and the stilling basin 12. It is a steep-slope type and is used to connect the unpressurized tunnel 10 and the stilling basin 12. The longitudinal slope and cross-sectional dimensions of the spillway 11 are determined according to the terrain conditions and the discharge flow to ensure a smooth transition of water flow.

[0030] The stilling basin 12, located downstream of the spillway 11, employs bottom flow energy dissipation and is used to consume the residual energy of the downstream flow. The depth and length of the stilling basin 12 are determined based on hydraulic calculations to ensure that the outflow velocity meets the specifications.

[0031] Abutment 13, located downstream of stilling basin 12, is a concrete structure used to protect the downstream riverbed from scouring and damage by the outflow. The length and thickness of abutment 13 are determined based on geological conditions and stilling basin outflow conditions.

[0032] Haiman 14 is located downstream of Hutan 13. It is constructed of dry-laid stone or precast concrete blocks to further dissipate the residual energy of the water flow and guide the water flow smoothly back to the river, preventing local scouring of the downstream riverbed.

[0033] The combination of vent 5 and pressure plate 6 eliminates the need for additional large-scale dedicated ventilation shafts, enabling the dual functions of ventilation and air replenishment in the shaft section and flow stabilization and control in the lower horizontal tunnel section. It features a compact structure and reliable operation.

[0034] The combined action of the deflector 9 and the vortex connection section ensures that the downstream water flow in the diversion tunnel 7 achieves a good energy dissipation effect, thereby further enhancing the stability of the water flow throughout the entire process.

[0035] This invention, taking into full account flood discharge safety, diversion requirements during construction, and structural stability during operation, provides a simple, economical, safe, and effective integrated permanent and temporary vertical shaft spillway structure and its layout scheme. This structure is well-suited for pumped storage power stations and conventional hydropower projects equipped with vertical shaft spillways and diversion tunnels, achieving a permanent and temporary integrated layout of the diversion tunnel and vertical shaft spillway, significantly reducing excavation and concrete lining work. By establishing a stable detached flow pattern through a sudden expansion section and ventilation holes at the shaft inlet, the risk of cavitation damage to the shaft wall from high-speed water flow is eliminated. The use of swirling mixing and energy dissipation in the stilling well at the bottom of the shaft and automatic aeration by the compressed air plate at the inlet of the unpressurized tunnel suppresses violent water surface fluctuations, ensuring stable open flow throughout the unpressurized tunnel. Furthermore, the combined energy dissipation and scour prevention through downstream spillways, stilling basins, aprons, and aprons ensures safe flood discharge throughout the entire process. This invention provides design ideas and references for the design of vertical shaft spillways in similar projects and has significant reference value.

[0036] The following example, using a pumped storage power station project that employs the technical solution of this invention, is further illustrated with reference to the accompanying drawings: As attached Figure 1 As shown, a pumped storage power station project adopts the wall-mounted spillway structure technology of this invention, which also takes into account construction flow guidance. The project completed a 1:20 hydraulic model test, comprehensively verifying key indicators such as discharge capacity, flow pattern, pressure distribution, energy dissipation efficiency, and ventilation velocity. The main design parameters are as follows: The annular overflow weir (1) adopts an annular practical weir with no gate on the top of the weir. The inner diameter of the top of the weir is 12m, the inner diameter of the bottom of the weir is 7m, and the height of the weir is 8.5m. The equation of the upstream curve of the weir surface is: -x / 0.7565=0.635(y / 0.7565). 0.410The equation of the downstream curve of the weir is: y / 0.7565 = 0.610(x / 0.7565) 1.85 The overflow weir connects to a vertical shaft section at its bottom, first connecting to a circular vertical shaft with an inner diameter of 7.0m, then connecting to another circular vertical shaft with an inner diameter of 5.0m, for a total depth of 97.88m. A sudden expansion section 2 is installed at the shaft inlet; the width of the expansion is determined by hydraulic calculations to ensure a stable flow pattern. Four vents 5 with a diameter of 40cm are arranged around the expansion section 2, communicating with the atmosphere to ensure that the maximum wind speed through the vents is below the standard limit of 60m / s under all operating conditions. To prevent direct impact of the water flow on the shaft floor, a circular stilling well 4 with a depth of 10m is installed at the bottom of the shaft. An arc-shaped deflector 9 is installed at the vortex connection interface between the shaft and the diversion tunnel 7, arranged circumferentially along the diversion tunnel; its height and spacing are optimized through model tests. The stilling well 4 is followed by a horizontal, unpressurized tunnel 10 shared with the downstream section of the diversion tunnel 7. The tunnel is 227m long with a slope of 1.5%. The tunnel cross-section is a city gate type with a net size of 5.0m × 4.5m (width × height) and a vertical wall height of 3.0m. The section connecting the stilling well 4 and the unpressurized tunnel 10 is equipped with a trapezoidal cross-section transverse convex structure of compressed air plate 6. The height and spacing are optimized and determined through model tests. The outlet of the unpressurized tunnel 10 adopts the bottom flow energy dissipation method, which consists of a spillway 11, a stilling pool 12, an apron 13, and a seawall 14. The spillway 11 is 15m long with a longitudinal slope of 1:4. It is followed by a stilling pool 12 with a length of 25m and a depth of 2m, and then by a 10m long concrete apron 13 and a reinforced gabion seawall 14 extending to the downstream riverbed. During the construction period, the diversion tunnel 7 undertakes all diversion tasks. During the operation period, the upstream diversion tunnel section of the vertical shaft is sealed by the plug 8, and the downstream section is converted into a permanent flood discharge channel.

[0037] The test results show that stable detached flow can be formed in the vertical shaft section under all working conditions, and a strongly mixed annular hydraulic jump is generated in the stilling well, with an overall energy dissipation rate of over 94%. At the check water level, the clearance at the top of the unpressurized tunnel is greater than 57.8%, the maximum wind speed at the vent is 28.6 m / s (far below the standard limit of 60 m / s), and the outflow velocity from the stilling basin is controlled below 4 m / s, indicating an ideal energy dissipation effect. The downstream spillway, stilling basin, apron, and apron work well together, and no obvious scouring damage was found.

[0038] Compared with conventional methods, the present invention can save about 220m of independent excavation length of diversion tunnel, reduce rock excavation by about 30,000 cubic meters, reduce concrete lining by about 5,000 cubic meters, and directly reduce project investment by about 6 million yuan.

[0039] The technical problem this invention aims to solve is to overcome the large engineering workload, high investment, and significant environmental damage caused by the independent arrangement of existing vertical shaft spillways and construction diversion tunnels, as well as the safety issues arising from the risks of well wall cavitation damage and downstream flow instability in conventional vertical shaft flood discharge methods. Based on a full consideration of the diversion requirements during construction, the safety of permanent flood discharge, and the structural stability during operation, this invention provides a simple, economical, safe, and effective permanent-temporary combined vertical shaft spillway structure. This structure organically combines the construction diversion tunnel with the permanent vertical shaft spillway, significantly reducing excavation and concrete lining work, minimizing environmental damage, eliminating the risk of cavitation damage to the well wall from high-speed water flow, and ensuring flood discharge safety and flow stability throughout the entire process from the shaft inlet to the downstream energy dissipation facility.

[0040] The permanent flood discharge structure adopts a vertical shaft spillway with a detached-wall flow. The inlet is arranged as a ring-shaped practical weir without a gate on the weir crest. The shaft inlet has a sudden expansion section, which allows the discharged water to form a stable "air-water-air" three-layer detached-wall flow pattern in the shaft section, achieving complete separation of the water flow from the shaft wall. Ventilation holes connected to the atmosphere are arranged around the sudden expansion section to maintain the stability of the detached-wall flow cavity, thereby eliminating the risk of cavitation damage to the shaft wall caused by high-speed water flow. A stilling well is set at the bottom of the shaft. After the detached water jet falls in, it dissipates energy through swirling mixing. A compressed air plate is installed at the connection section between the stilling well and the unpressurized tunnel. The system utilizes the kinetic energy of the water flow to entrain air, suppressing violent fluctuations on the water surface and eliminating the alternation of open and full flow. After passing through the unpressurized tunnel, the water flow sequentially enters the spillway, stilling basin, apron, and seawall, completing downstream energy dissipation and scour prevention. The temporary diversion tunnel is located upstream of the shaft, taking into account the site's topography and geological conditions. It connects to the shaft using a vortex flow method and is equipped with a deflector to adjust the flow pattern of the downstream water. During the construction period, the diversion tunnel undertakes all diversion tasks. During the operation period, only a short plug needs to be installed in the diversion tunnel upstream of the shaft to seal it, and the downstream section is converted into a permanent flood discharge channel.

[0041] The embodiments described above are only used to illustrate the technical ideas and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The patent scope of the present invention should not be limited by these embodiments. That is, any equivalent changes or modifications made in accordance with the spirit disclosed in the present invention still fall within the patent scope of the present invention.

Claims

1. A vertical shaft spillway structure that also considers construction flow diversion, characterized in that, include: An annular overflow weir (1) is located at the inlet of the shaft, with no gate on the weir crest; The shaft body section (3) is connected below the annular overflow weir (1); The sudden expansion section (2) is set at the connection between the annular overflow weir (1) and the vertical shaft section (3) to make the downstream water flow form a wall-detached flow state in the vertical shaft section (3) where the water flow separates from the shaft wall; Ventilation holes (5) are arranged around the sudden expansion section (2) and are open to the atmosphere. They are used to replenish air into the vertical shaft to maintain the stability of the detachment flow cavity. A stilling well (4) is located at the bottom of the shaft section (3); A diversion tunnel (7) is arranged on the upstream side of the shaft section (3), and the downstream section of the diversion tunnel (7) also serves as a permanent flood discharge channel; An unpressurized tunnel (10) is connected between the downstream section of the stilling well (4) and the diversion tunnel (7); The plug (8) is installed in the diversion tunnel on the upstream side of the shaft section (3) and is used to seal the upstream section of the diversion tunnel during operation; Air pressure plate (6) is installed at the connection section between the stilling well (4) and the unpressurized tunnel (10) to suppress water surface fluctuations; A flow deflector (9) is installed at the connection interface between the vertical shaft section (3) and the guide tunnel (7) to guide the downstream water flow to form a rotating flow pattern; And the vent (11), stilling basin (12), abutment (13) and seawall (14) connected in sequence downstream of the unpressurized tunnel (10).

2. The vertical shaft spillway structure for detached flow that also considers construction diversion as described in claim 1, characterized in that, The annular overflow weir (1) is an annular practical weir; the sudden expansion section (2) utilizes the combined effect of sudden expansion separation and centripetal aggregation of the vertical shaft annular overflow to form a "gas-water-gas" three-layer detached flow state in the vertical shaft section (3) of the discharge water flow.

3. The vertical shaft spillway structure for detached flow that also considers construction diversion as described in claim 1, characterized in that, The energy dissipation well (4) has a circular cross-section, and no energy dissipation device is installed on the well wall of the energy dissipation well (4).

4. The vertical shaft spillway structure for detached flow that also considers construction diversion as described in claim 1, characterized in that, There are multiple vent holes (5), which are arranged circumferentially along the expansion section (2).

5. The vertical shaft spillway structure for detached flow that also considers construction diversion as described in claim 1, characterized in that, The air pressure plate (6) is a transverse convex structure with a trapezoidal cross section, and is located at the bottom of the connection section between the stilling well (4) and the pressureless tunnel (10).

6. The vertical shaft spillway structure for detached flow that also considers construction diversion as described in claim 1, characterized in that, The vertical shaft section (3) is perpendicularly connected to the diversion tunnel (7). During the construction period, the diversion tunnel (7) undertakes the task of diversion. During the operation period, the upstream section of the diversion tunnel is sealed by the plug (8), and the downstream section of the diversion tunnel is converted into a permanent flood discharge channel.

7. The vertical shaft spillway structure for detached flow that also considers construction diversion as described in claim 1, characterized in that, The flow deflector (9) has an arc-shaped cross-section structure and is arranged along the circumference of the flow guide tunnel (7) at the connection interface between the vertical shaft section (3) and the flow guide tunnel (7).

8. The vertical shaft spillway structure for detached flow that also considers construction diversion as described in claim 1, characterized in that, The trough (11) is a steep trough, and the stilling pool (12) is a bottom flow stilling pool.

9. The vertical shaft spillway structure for detached flow that also considers construction diversion according to any one of claims 1 to 8, characterized in that, The diameter and number of the ventilation holes (5) are configured such that the maximum wind speed of the ventilation holes is less than 60m / s under each working condition.

10. The vertical shaft spillway structure for detached flow that also considers construction diversion according to any one of claims 1 to 8, characterized in that, The inner diameter of the top of the annular overflow weir (1) is 8-15m, the inner diameter of the bottom is 5-10m, and the height is 5-12m; the depth of the shaft section (3) is 80-120m; the diameter of the ventilation holes (5) is 30-60cm, and the number is 3-6; the depth of the stilling well (4) is 5-15m; the cross-section of the pressureless tunnel (10) is a city gate type.

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