A flood discharge and ecological water release combined energy dissipation system

Abstract

This invention relates to the field of water conservancy and hydropower engineering technology, specifically to a combined energy dissipation system for flood discharge and ecological water release. It includes a flood discharge tunnel, an energy dissipation unit, an ecological water conveyance unit, and a connecting unit. A main flood discharge channel is formed between two retaining walls, and a reserved cavity is provided on the outer side of at least one of the retaining walls. The energy dissipation unit is arranged within the reserved cavity and shares the corresponding side of the retaining wall with the flood discharge tunnel. An ecological water release pipe is buried below the bottom slab of the flood discharge tunnel, with its outlet end leading into the energy dissipation unit. The connecting unit introduces the ecological water flow after primary energy dissipation in the energy dissipation unit into the main flood discharge channel, where it merges with the main flood discharge flow for secondary coordinated energy dissipation. This system achieves the reuse of the outer cavity of the flood discharge tunnel's retaining walls and its existing energy dissipation capacity, enabling the ecological water flow and the main flood discharge flow to form a combined and coordinated energy dissipation in terms of structural space and energy dissipation function.

Description

Technical Field

[0001] This invention relates to the field of water conservancy and hydropower engineering technology, specifically to a combined energy dissipation system for flood discharge and ecological water release. Background Technology

[0002] In water conservancy and hydropower projects, flood discharge tunnels (including sediment discharge tunnels) are the core facilities for ensuring the safety of flood control and sediment discharge at the hub. Their structure is built to high standards in one go, forming a flood discharge channel enclosed by a bottom slab and side walls. At the same time, in order to maintain the ecological base flow of the downstream river, it is necessary to install dedicated ecological water discharge pipes and supporting energy dissipation facilities to eliminate the energy of high-speed water flow and prevent scouring damage.

[0003] Currently, ecological water release pipes and flood discharge tunnels are constructed independently and in parallel. Ecological water release pipes are laid separately, bypassing the main structure of the flood discharge tunnel, and a dedicated stilling basin is built downstream. Ecological water flows through the stilling basin to dissipate energy before being discharged separately into the downstream river channel, where it disperses and merges with the flood discharge flow. Therefore, the ecological water release pipe and the flood discharge tunnel form independent systems, spatially separated. However, this complete separation of space and function not only occupies valuable land resources and increases project investment, but more importantly, the ecological water flow and the flood discharge flow lack coordination in structural layout and hydraulic connection. The two systems operate independently, failing to utilize the existing structural space and energy dissipation capacity of the flood discharge tunnel, resulting in a loose overall layout and chaotic hydraulic connection. This makes it difficult to achieve the goal of intensive and efficient energy dissipation in new projects with limited space. Summary of the Invention

[0004] This invention provides a combined energy dissipation system for flood discharge and ecological water release, which solves the problem that when the ecological water release pipe and the flood discharge tunnel are constructed independently, the two systems are completely separated in terms of spatial layout and hydraulic connection, and lack coordination.

[0005] To address the above problems, this invention provides a combined flood discharge and ecological water release energy dissipation system, comprising: The flood discharge tunnel is an independent tunnel located on the mountainside of the hub. The downstream outlet of the flood discharge tunnel is provided with two vertical water-retaining sidewalls, and the main flood discharge channel is formed between the two water-retaining sidewalls. At least one side of the water-retaining sidewall is provided with a reserved cavity on its outer side. An energy dissipation unit is arranged in the reserved cavity and shares the corresponding side retaining wall with the flood discharge and drainage tunnel. The bottom plate elevation of the energy dissipation unit is lower than the bottom plate elevation of the main flood discharge channel. An ecological water conveyance unit includes an ecological water discharge pipe, which is buried below the bottom plate of the flood discharge tunnel, and the outlet end of the ecological water discharge pipe leads into the interior of the energy dissipation unit. The connecting unit, which is located on the shared water-retaining side wall, is used to introduce the ecological water flow after the first-stage energy dissipation in the energy dissipation unit into the main flood discharge channel, and to merge with the main flood discharge flow in the main flood discharge channel for secondary coordinated energy dissipation.

[0006] Preferably, the reserved cavity is located between the water-retaining sidewall and the surrounding rock of the mountain on the side away from the main body of the dam, and the energy dissipation unit is integrally connected with the flood discharge and emptying tunnel by sharing the water-retaining sidewall on the side away from the main body of the dam.

[0007] Preferably, the ecological water conveyance unit further includes a flow control device, which is located at the inlet end of the ecological water discharge pipe and is used to adjust the water conveyance flow of the ecological water discharge pipe according to the downstream ecological flow demand.

[0008] Preferably, the ecological water discharge pipe is laid along the axis of the flood discharge tunnel and along the longitudinal slope of the flood discharge tunnel.

[0009] Preferably, when the space below the bottom slab of the flood discharge tunnel is limited, the ecological water discharge pipe is buried inside the wall of the shared water-retaining side wall. The pipe body of the ecological water discharge pipe is laid horizontally at the same height, and the ecological water discharge pipe passes through the outside of the water-retaining side wall and is connected to the cavity energy dissipation unit below the external short pipe.

[0010] Preferably, the connecting unit consists of multiple overflow holes evenly distributed on the shared vertical sidewall, each overflow hole penetrating the water-retaining sidewall, the bottom elevation of the overflow hole being lower than the normal operating water level of the energy dissipation unit, and the water flow direction of the overflow hole being consistent with the flow direction of the main flood discharge channel.

[0011] Preferably, the connecting unit is a curved overflow weir installed on the shared water-retaining sidewall, and the crest elevation of the curved overflow weir is lower than the normal operating water level of the energy dissipation unit.

[0012] Preferably, the cavity energy dissipation unit is a stilling pool structure.

[0013] Preferably, the cavity energy dissipation unit is provided with energy dissipation blocks and / or energy dissipation grooves as auxiliary energy dissipation components.

[0014] Preferably, the stilling basin and the water-retaining sidewall are integrally cast concrete structures; an outlet energy dissipation facility is provided downstream of the main flood discharge channel, and the ecological water flow introduced through the connecting unit merges with the main flood discharge flow and undergoes secondary coordinated energy dissipation through the outlet energy dissipation facility.

[0015] Beneficial technical effects of the present invention: This invention discloses a combined energy dissipation system for flood discharge and ecological water release. The energy dissipation unit is directly arranged within a reserved cavity on the outer side of the retaining wall of the flood discharge tunnel, sharing the corresponding side retaining wall with the tunnel. Simultaneously, the ecological water release pipe is buried beneath the bottom slab of the flood discharge tunnel, utilizing the existing underground space below the slab. Thus, the energy dissipation unit and the ecological water release pipe are spatially integrated within the main structural outline of the flood discharge tunnel, eliminating the need for separate land acquisition and construction of an independent stilling basin, achieving intensive spatial reuse of the main and ecological facilities. The bottom slab elevation of the energy dissipation unit is lower than that of the main flood discharge channel. After entering the energy dissipation unit, the ecological water flow undergoes primary energy dissipation via a cascade. The dissipated water then flows smoothly into the main flood discharge channel through a connecting unit located on the shared retaining wall, merging with the main flood discharge flow. After energy dissipation, the ecological water flow and the main flood discharge flow converge in the same direction. After the two flows merge in the main flood discharge channel, secondary coordinated energy dissipation is completed using the existing outlet energy dissipation facilities downstream of the flood discharge tunnel. Thus, the ecological water flow and the main flood discharge flow achieve synergy in hydraulic connection, forming primary energy dissipation, co-current flow, and secondary coordinated energy dissipation, thereby improving the overall energy dissipation efficiency and hydraulic performance of the hub.

[0016] Therefore, this invention solves the problem that when the ecological water release pipe and the flood discharge tunnel are constructed independently, the two systems are completely separated in terms of spatial layout and hydraulic connection and lack coordination. It realizes the reuse of the outer cavity of the flood discharge tunnel sidewall and the existing energy dissipation capacity, so that the ecological water flow and the flood discharge mainstream form a joint coordination in terms of structural space and energy dissipation function. Attached Figure Description

[0017] Figure 1 This is a top view schematic diagram of a combined flood discharge and ecological water release energy dissipation system according to an embodiment of the present invention; Figure 2 for Figure 1 Sectional view 1-1; Figure 3 for Figure 1 AA sectional view.

[0018] Explanation of reference numerals in the attached drawings: 1-Flood discharge and emptying tunnel; 11-Water-retaining sidewall; 01-Main flood discharge channel; 2-Energy dissipation unit; 3-Ecological water conveyance unit; 31-Ecological water discharge pipe; 32-Flow regulation device; 4-Connecting unit. Detailed Implementation

[0019] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0020] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first," "second," etc., mentioned in this invention are used only to distinguish different devices, modules, or components, and are not intended to limit the order of functions performed by these devices, modules, or components or their interdependencies.

[0021] It should be noted that the terms "a" and "a plurality of" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0022] See Figures 1 to 3 As shown. To address the problems existing in the aforementioned related technologies, this embodiment of the invention provides a combined flood discharge and ecological water release energy dissipation system, including a flood discharge tunnel 1, an energy dissipation unit 2, an ecological water conveyance unit 3, and a connecting unit 4. The flood discharge tunnel 1 is an independent tunnel located on the mountainside of the hub. The downstream outlet of the flood discharge tunnel 1 is provided with two vertical water-retaining sidewalls 11, forming a main flood discharge channel 01 between the two water-retaining sidewalls 11. At least one side of the water-retaining sidewall 11 has a reserved cavity on its outer side. The energy dissipation unit 2 is arranged within the reserved cavity and connects with the flood discharge tunnel. The cavity 1 shares the corresponding water-retaining sidewall 11, and the bottom plate elevation of the energy dissipation unit 2 is lower than the bottom plate elevation of the main flood discharge channel 01; the ecological water conveyance unit 3 includes an ecological water discharge pipe 31, which is buried below the bottom plate of the flood discharge cavity 1, and the outlet end of the ecological water discharge pipe 31 is connected to the interior of the energy dissipation unit 2; the connecting unit 4 is opened on the shared water-retaining sidewall 11, and is used to introduce the ecological water flow after the first-stage energy dissipation in the energy dissipation unit 2 into the main flood discharge channel 01, and merge with the main flood discharge flow in the main flood discharge channel 01 for secondary coordinated energy dissipation.

[0023] It should be noted that, in this embodiment of the invention, the energy dissipation unit 2 is directly arranged in the reserved cavity outside the water-retaining sidewall 11 of the flood discharge tunnel 1, sharing the corresponding side water-retaining sidewall 11 with the flood discharge tunnel 1; at the same time, the ecological water discharge pipe 31 is buried below the bottom slab of the flood discharge tunnel 1, utilizing the existing underground space below the bottom slab. Thus, the energy dissipation unit 2 and the ecological water discharge pipe 31 are completely incorporated into the main structural outline of the flood discharge tunnel 1, eliminating the need for separate land acquisition and construction of an independent energy dissipation pool, and achieving intensive spatial reuse of the main facilities and ecological facilities.

[0024] The bottom elevation of energy dissipation unit 2 is lower than that of the main flood discharge channel 01. After entering energy dissipation unit 2, the ecological water flow completes primary energy dissipation through a drop flow. The dissipated water flow then smoothly enters the main flood discharge channel 01 through connecting unit 4 located on the shared retaining wall 11, overflowing in the same direction and merging with the main flood discharge flow. Since the outlet direction of connecting unit 4 is consistent with the flow direction of the main flood discharge channel 01, the dissipated ecological water flow and the main flood discharge flow form a co-current convergence. After the two flows merge in the main flood discharge channel 01, they complete secondary coordinated energy dissipation using the existing outlet energy dissipation facilities downstream of the flood discharge tunnel 1. Thus, the ecological water flow and the main flood discharge flow achieve synergy in terms of hydraulic connection, forming primary energy dissipation, co-current convergence, and secondary coordinated energy dissipation, thereby improving the overall energy dissipation efficiency and hydraulic performance of the hub.

[0025] Energy dissipation unit 2 shares a retaining wall 11 with the flood discharge tunnel 1. Connecting unit 4 is directly installed on this shared retaining wall 11. Energy dissipation unit 2 can be pre-installed or integrally cast during the construction of the main structure of the flood discharge tunnel 1. Ecological drainage pipe 31 is buried under the bottom slab of the flood discharge tunnel 1 and can be laid together during the bottom slab construction stage. Thus, energy dissipation unit 2, ecological drainage pipe 31, and the main structure of the flood discharge tunnel 1 form an integrated and coordinated arrangement, avoiding separate excavation and modification construction in the later stage, reducing interference from cross-operations, shortening the construction period, and ensuring the integrity and stability of the shared structure.

[0026] In summary, the energy dissipation system combining flood discharge and ecological water release of the present invention enables the reuse of the outer cavity of the flood discharge tunnel sidewall and the existing energy dissipation capacity, so that the ecological water flow and the main flood discharge flow form a joint synergy in terms of structural space and energy dissipation function.

[0027] In one embodiment of the present invention, a reserved cavity is set between the water-retaining sidewall 11 on the side away from the main body of the dam and the surrounding rock of the mountain. The energy dissipation unit 2 is arranged in an integral connection with the flood discharge tunnel 1 by sharing the water-retaining sidewall 11 on the side away from the main body of the dam.

[0028] It should be noted that the flood discharge tunnel 1 is located on the mountainside of the hub, with its retaining wall 11 on the side away from the main dam directly adjacent to the surrounding rock. This area naturally exists or forms a cavity space due to construction needs during the tunnel excavation. Placing the energy dissipation unit 2 here can make full use of the existing excavated space between the surrounding rock and the retaining wall 11, or the reserved cavity formed by simple modification, without additional excavation or separate land acquisition. This transforms a space that might otherwise be backfilled or abandoned into a facility carrier with energy dissipation function, realizing the resource reuse of engineering space. At the same time, the retaining wall 11 on the side away from the main dam is relatively independent of the main dam structure in space. The construction of the energy dissipation unit 2 and the connection of the ecological water release pipe 31 are all completed on this side, avoiding cross-operation interference with the main dam construction area. This is conducive to the independent advancement of construction organization by zone and reduces the difficulty of construction coordination.

[0029] In one embodiment of the present invention, the ecological water conveyance unit 3 further includes a flow control device 32, which is located at the inlet end of the ecological water discharge pipe 31 and is used to adjust the water conveyance flow of the ecological water discharge pipe 31 according to the downstream ecological flow demand.

[0030] Specifically, the flow control device 32 can be an electric flow control valve assembly or a water level-linked hydraulic automatic control valve assembly. The electric flow control valve assembly is linked with the downstream hydrological monitoring system and automatically adjusts the valve opening according to the real-time demand of the downstream river's ecological base flow, thereby controlling the water flow of the ecological discharge pipe 31. The hydraulic automatic control valve assembly does not require an external power supply. Instead, it utilizes changes in water level within the energy dissipation unit 2 or changes in pressure difference between the upstream and downstream of the pipeline to automatically adjust the valve opening through mechanical linkage mechanisms such as floats, connecting rods, and valve cores. When the water level in the energy dissipation unit 2 rises, it indicates insufficient downstream outflow capacity or excessive ecological flow, and the automatic control valve assembly automatically reduces the opening; when the water level falls, it automatically increases the opening.

[0031] It should be noted that, with the matching configuration of the flow control device 32, the ecological water conveyance unit 3 is no longer a simple passive discharge pipe, but an ecological flow guarantee system with active control capabilities. When there is no need to discharge ecological flow, the water conveyance can be stopped by closing the flow control device 32. The remaining water in the energy dissipation unit 2 is gradually discharged into the main flood discharge channel 01 through the connecting unit 4 and then naturally emptied, avoiding long-term water accumulation in the energy dissipation unit 2, which could breed microorganisms or produce silt, and reducing the amount of dredging and maintenance work in the later stage.

[0032] In one embodiment of the present invention, the ecological water discharge pipe 31 is laid along the tunnel axis of the flood discharge tunnel 1 and along the longitudinal slope of the flood discharge tunnel 1.

[0033] It should be noted that in this embodiment, the ecological water discharge pipe 31 is buried below the bottom slab of the flood discharge tunnel 1, laid directly in a straight line along the tunnel's axis. The pipe path is completely consistent with the main structure of the flood discharge tunnel 1, eliminating the need for additional bends or bends to bypass the main structure. This minimizes the pipe's path from the inlet to the outlet, reducing material consumption and excavation work, and lowering project investment. The ecological water discharge pipe 31 is laid in a straight line along the longitudinal slope of the flood discharge tunnel 1, without any bends. This means the ecological water flow does not experience any abrupt changes in direction within the pipe, avoiding local head loss, turbulence, and cavitation risks associated with bends. The water flow within the pipe is stable with minimal energy loss, effectively maintaining the outlet velocity and pressure at the pipe's end. Simultaneously, the slope-following laying ensures the pipe's longitudinal slope matches the bottom slope of the flood discharge tunnel 1, resulting in a uniform slope that facilitates the smooth transport of solid materials such as sediment within the pipe, reducing the risk of siltation. Furthermore, the laying path of the ecological water discharge pipe 31 is completely parallel to the axis of the flood discharge tunnel 1, maintaining spatial consistency in both plan and longitudinal sections. This means that during the concrete pouring stage of the flood discharge tunnel 1's foundation slab, the ecological water discharge pipe 31 can be installed simultaneously as an embedded component, laid in one go, eliminating the need for separate excavation and backfilling of the pipeline trench after the main structure is completed, thus reducing construction procedures and time spent on overlapping work. In the later operation and maintenance phase, the pipeline's location is clearly defined, and its relative spatial relationship with the flood discharge tunnel 1 is simple and clear, facilitating full-line inspection and fault location using pipeline testing equipment.

[0034] In one embodiment of the present invention, when the space below the bottom plate of the flood discharge tunnel 1 is limited, the ecological water discharge pipe 31 is buried inside the wall of the shared water retaining wall 11. The pipe body of the ecological water discharge pipe 31 is laid horizontally at the same height, and the ecological water discharge pipe 31 passes through the outside of the water retaining wall 11 and is connected to the cavity energy dissipation unit 2 below the external short pipe.

[0035] Specifically, whether the ecological water discharge pipe 31 is laid below the bottom slab of the flood discharge and sediment flushing tunnel 1 or inside the shared retaining wall 11 is not limited by a single spatial condition, but mainly depends on the coordination between the bottom elevation of the energy dissipation unit 2 to which the outlet end of the ecological water discharge pipe 31 is connected and the installation elevation of the flow control device 32 connected to the inlet end. The laying path of the ecological water discharge pipe 31 can be flexibly changed between below the bottom slab and inside the retaining wall, based on the principle of smooth connection between the inlet end of the pipe and the flow control device 32, and reasonable matching of the energy dissipation drop between the outlet end and the energy dissipation unit 2. When the bottom elevation of the energy dissipation unit 2 is low and the outlet end of the pipe needs to be moved down accordingly, laying it below the bottom slab can be given priority; when the flow control device 32 is located at a higher position, or the bottom elevation of the energy dissipation unit 2 is relatively high, the ecological water discharge pipe 31 can be moved to the inside of the retaining wall 11 and laid at the same level, so that the overall elevation of the pipe is coordinated with the valve outlet elevation and the connection elevation of the energy dissipation unit 2. As an existing structural component of the flood discharge and sediment flushing tunnel 1, the retaining wall 11 typically has the space to accommodate pipelines within its interior, provided that the structural reinforcement and protective layer requirements are met. Therefore, this scheme has good engineering adaptability. During construction, the ecological water discharge pipe 31 is precisely positioned according to the design elevation and horizontal position and then fixed inside the steel reinforcement frame of the retaining wall. It is gradually wrapped and formed as the retaining wall concrete is poured in layers, and the entire process is completed in one go.

[0036] It should be noted that the ecological water discharge pipe 31 is laid in a straight line without bends within the main structure of the flood discharge tunnel 1 (below the bottom plate or inside the wall). However, in the area where the pipe inlet is connected to the flow control device 32, due to the spatial position of the gate control room or valve well, it may be necessary to make appropriate directional adjustments through a bend before connecting to the energy dissipation unit 2.

[0037] It should be noted that the ecological water discharge pipe 31 is laid horizontally at the same height inside the retaining wall 11, maintaining a straight and horizontal position to avoid hydraulic losses caused by forced bends due to insufficient space. The pipe exits directly from the outside of the retaining wall 11, and the outlet end is connected to the energy dissipation unit 2 through an external short pipe, making the entire outflow path short and straight. Compared with the scheme where the pipe is laid below the bottom slab, this scheme raises the pipe outlet position to within the height range of the side wall. When the water flows into the energy dissipation unit 2, it forms a drop in elevation. This, combined with the low-level energy dissipation design where the bottom slab elevation of the energy dissipation unit 2 is lower than that of the main flood discharge channel 01, allows the water to dissipate kinetic energy by falling into the energy dissipation unit 2, and the primary energy dissipation effect remains unaffected.

[0038] In one embodiment of the present invention, the connecting unit 4 consists of multiple overflow holes evenly distributed on a common vertical sidewall. Each overflow hole penetrates the water-retaining sidewall 11. The bottom elevation of the overflow hole is lower than the normal operating water level of the energy dissipation unit 2, and the water flow direction of the overflow hole is consistent with the flow direction of the main flood discharge channel 01.

[0039] It should be noted that the number and spacing of the overflow orifices are mainly determined based on the ecological flow required to be discharged from energy dissipation unit 2 and the allowable head above the weir. When the ecological flow is large, the number of overflow orifices or the size of each orifice can be increased to increase the total flow area, keeping the water level within a reasonable range. This ensures that the water flow in energy dissipation unit 2 can overflow into the main flood discharge channel 01 in a timely and smooth manner, avoiding any impact on the energy dissipation effect or causing water to overflow from the top of energy dissipation unit 2. When the ecological flow is small, the number of overflow orifices can be reduced accordingly, simplifying the structural layout while still meeting the flow capacity requirements. Regardless of the specific number and arrangement of the overflow orifices, their bottom elevation is always lower than the normal operating water level of energy dissipation unit 2. This elevation relationship ensures that under normal operating conditions, there is sufficient submerged water depth within energy dissipation unit 2 to cover the overflow orifices. The water flow enters the main flood discharge channel 01 through the overflow orifices in the form of weir flow or submerged outflow, resulting in a stable and controllable outflow. More importantly, the overflow outlet direction is consistent with the flow direction of the main flood discharge channel 01. When the energy-dissipated ecological water flow merges with the main flood discharge flow, it forms a co-current flow, avoiding violent mixing, turbulence and energy loss at the water flow intersection. The water flow in the confluence area is stable and there will be no backflow zone or local scour zone, which improves the hydraulic connection conditions of the hub outlet.

[0040] In one embodiment of the present invention, the connecting unit 4 is a curved overflow weir arranged on the common water-retaining sidewall 11, and the crest elevation of the curved overflow weir is lower than the normal operating water level of the energy dissipation unit 2.

[0041] It should be noted that the weir surface of a curved overflow weir typically adopts a hydraulically optimized curved profile, such as a WES weir or a power curve weir. After the water flows over the weir crest, it can flow down the curve of the weir surface, avoiding the separation of the water flow from the weir surface and the creation of cavities and negative pressure zones. Under the premise of meeting the same ecological flow discharge requirements, the curved overflow weir requires a shorter flow front length, which helps to reduce the planar dimensions of the energy dissipation unit 2 and further save space. At the same time, the weir crest elevation is lower than the normal operating water level, ensuring that the weir flow is always in a submerged outflow state, and the outflow is stable and controllable.

[0042] In one embodiment of the present invention, the cavity energy dissipation unit 2 is a heat dissipation pool structure.

[0043] It should be noted that the stilling basin is an open-topped, box-type water tank structure. Specifically, the stilling basin and the shared retaining wall 11 can be integrated into a single structure through integral casting or coordinated lining. The retaining wall 11 serves as one side wall of the stilling basin. The bottom slab reinforcement of the stilling basin and the vertical reinforcement of the retaining wall 11 can be cross-anchored. The concrete is integrally cast, and no waterstop or expansion joint is required at the joints. The structural integrity and seepage prevention performance are superior to that of a separately constructed stilling basin. The outer wall of the stilling basin can be flexibly treated according to the cavity boundary conditions: if the outer side of the cavity is mountain rock, the rock surface can be directly used as the outer boundary of the stilling basin after shotcrete and anchor support or lining treatment; if the outer side of the cavity is a separately cast concrete wall, it is integrally connected to the bottom slab.

[0044] The bottom elevation of the stilling basin is lower than that of the main flood discharge channel 01. The difference in elevation between the two is determined based on the outlet flow velocity of the ecological water discharge pipe 31 and the energy dissipation requirements, and the range of the difference is usually 1.0 meter to 3.0 meters. When the ecological water flows out from the outlet of the ecological water discharge pipe 31 at a certain flow velocity, the water spreads and falls in the stilling basin, and the first energy dissipation is completed by utilizing the drop height difference and the water cushion depth. The flow velocity decreases and the flow pattern changes from rapid flow to slow flow.

[0045] In one embodiment of the present invention, the cavity energy dissipation unit 2 is provided with energy dissipation blocks and / or energy dissipation grooves as auxiliary energy dissipation components.

[0046] It should be noted that the basic energy dissipation method of a stilling basin relies on the hydraulic jump formed by the cascading water flow, which dissipates energy through turbulent mixing within the water body. However, when the ecological outflow increases to a certain extent, relying solely on the free turbulence of the water body within the basin requires a significantly increased hydraulic jump length and basin length. Given the limited length of the cavity reserved outside the sidewalls, a fully developed hydraulic jump may not be formed, resulting in some water flow energy overflowing through the connecting unit 4 without effective dissipation, increasing the burden of secondary coordinated energy dissipation. In this embodiment, energy dissipation piers and / or energy dissipation channels are added inside the energy dissipation unit 2. By setting obstacles or abrupt changes in the water flow path, the water flow is forced to produce local impacts, diversions, deflections, and intense mixing, consuming more water flow energy within a shorter basin length. Energy dissipation piers are typically vertical piers arranged on the bottom plate. After the water flow impacts the piers, it creates a backflow and bypass, resulting in strong local head loss. Energy dissipation channels are typically grooves or protrusions traversing the bottom plate. When the water flow passes through the channels, it generates cascading flow and vortices, further dissipating energy. Both can be used individually or combined to form a multi-level auxiliary energy dissipation system.

[0047] In one embodiment of the present invention, the stilling basin and the water-retaining side wall 11 are integrally cast concrete structures; an outlet energy dissipation facility is provided downstream of the main flood discharge channel 01, and the ecological water flow introduced through the connecting unit 4 merges with the main flood discharge flow and jointly conducts secondary coordinated energy dissipation through the outlet energy dissipation facility.

[0048] It should be noted that the stilling basin and the retaining wall 11 are integrally cast concrete structures, making the bottom slab of the stilling basin and the root of the retaining wall 11 integrally connected. The sidewall of the stilling basin is the shared retaining wall 11, and there are no construction joints or structural joints between the two. This integrated construction method eliminates the weak surface of the construction joint between the independent stilling basin and the main structure of the flood discharge tunnel. The overall rigidity, seismic performance, and seepage prevention performance of the structure are all superior to the separate construction scheme. At the same time, since the connecting unit 4 is opened on the shared retaining wall 11, the openings or weir surface templates of the overflow hole, overflow weir, and other connecting structures can be reserved simultaneously during the casting of the retaining wall 11. There is no need to drill or cut after the concrete has hardened, avoiding disturbance and secondary damage to the formed structure, and also reducing the construction procedures and time required for later modifications.

[0049] Meanwhile, downstream of the main flood discharge channel 01, there are outlet energy dissipation facilities, such as stilling basins, stilling sills, and integrated stilling ponds. After the ecological water flow introduced through the connecting unit 4 merges with the main flood discharge flow, they jointly complete secondary coordinated energy dissipation through this outlet energy dissipation facility. This feature reflects the complete hydraulic design logic of the present invention of graded energy dissipation and step-by-step dissipation: First, the ecological water flow completes preliminary energy dissipation in the energy dissipation unit 2 through cascades and hydraulic jumps, reducing the flow velocity; Second, the ecological water flow after preliminary energy dissipation smoothly overflows into the main flood discharge channel 01 through the connecting unit 4, forming a co-current flow with the main flood discharge flow; Third, after the two water flows are fully mixed in the main flood discharge channel 01, they jointly enter the downstream outlet energy dissipation facility, utilizing the original stilling basin volume and energy dissipation structure of the facility to complete the final coordinated energy dissipation, and are discharged into the downstream river channel at a safe flow velocity. Through this graded and coordinated energy dissipation model, the outlet velocity of the ecological water flow is significantly reduced after passing through two stages of energy dissipation, which weakens the scouring intensity on the downstream riverbed and banks. At the same time, the capacity of the energy dissipation facilities at the outlet of the flood discharge tunnel can take into account the inflow of ecological flow during the design stage, so as to realize the sharing of energy dissipation capacity and avoid the investment redundancy caused by setting up energy dissipation facilities separately.

[0050] An embodiment of the present invention provides a combined energy dissipation operation method based on the above-described combined energy dissipation system of flood discharge and ecological water release, comprising the following steps: S1. Ecological flow regulation and stable transport: Based on the downstream river's ecological base flow requirements, the flow control device 32 located at the inlet of the ecological water discharge pipe 31 is activated. The section of the ecological water discharge pipe 31 laid below the bottom slab of the flood discharge tunnel 1 or inside the shared water-retaining sidewall 11 is arranged in a straight line without bends along the tunnel axis. Its inlet is connected to the flow control device 32 via a connecting pipe. After being regulated by the flow control device 32, the ecological water flow is smoothly transported by the ecological water discharge pipe 31 to the energy dissipation unit 2 located in the reserved cavity at a lower position.

[0051] S2, Level 1 Flow Dissipation: The ecological water flow enters the energy dissipation unit 2 from the outlet end of the ecological water discharge pipe 31. Utilizing the vertical energy dissipation drop formed by the lower elevation of the bottom plate of the energy dissipation unit 2 compared to the bottom plate of the main flood discharge channel 01, the water flow falls in the form of a cascade and forms violent turbulence and mixing within the energy dissipation unit 2, completing the first stage of kinetic energy dissipation.

[0052] S3, Same-direction overflow connection: As ecological water flow continues to be injected, the water level in energy dissipation unit 2 gradually rises; when the water level rises above the bottom elevation of the overflow hole of the connecting unit 4 opened on the common water-retaining sidewall 11, the ecological water flow after primary energy dissipation flows smoothly into the main flood discharge channel 01 through the connecting unit 4 in the same direction.

[0053] S4, Secondary Cooperative Energy Dissipation: The ecological water flow that overflows into the main flood discharge channel 01 mixes thoroughly with the main flood discharge flow within the channel. After the two water flows merge, they enter the outlet energy dissipation facility downstream of the flood discharge tunnel 1. The outlet energy dissipation facility is used to complete secondary coordinated energy dissipation, and finally the water flows down to the downstream river channel in a unified and stable manner.

[0054] S5. Shutdown and venting: When there is no need to release ecological flow, the flow control device 32 located at the inlet of the ecological water discharge pipe 31 is closed, and the water supply to the energy dissipation unit 2 is stopped; the residual water in the energy dissipation unit 2 is automatically discharged back into the main flood discharge channel 01 through the connecting unit 4 opened on the shared water retaining wall 11, so as to realize the automatic emptying of the energy dissipation unit 2.

[0055] Through the above-mentioned S1 to S5 operation steps, the ecological water flow is transported without bends through the ecological water discharge pipe 31, the first-level drop flow energy dissipation of the energy dissipation unit 2, the same-direction overflow connection of the connecting unit 4, the secondary coordinated energy dissipation of the energy dissipation facilities at the outlet of the flood discharge tunnel 1, and the automatic emptying of the energy dissipation unit 2 after shutdown. This achieves complete coordination between the ecological water flow and the main flood discharge flow in terms of spatial arrangement, hydraulic connection and energy dissipation function, and achieves the unified goal of reliable ecological flow discharge, full dissipation of water flow energy and efficient coordination of engineering facilities.

[0056] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A combined energy dissipation system for flood discharge and ecological water release, characterized in that, include: The flood discharge tunnel (1) is an independent tunnel located on the mountainside of the hub. The downstream outlet of the flood discharge tunnel (1) is provided with two vertical water-retaining sidewalls (11). The two water-retaining sidewalls (11) form a main flood discharge channel (01). At least one side of the water-retaining sidewall (11) has a reserved cavity on its outer side. Energy dissipation unit (2), the energy dissipation unit (2) is arranged in the reserved cavity and shares the corresponding side of the water-retaining sidewall (11) with the flood discharge and emptying tunnel (1). The bottom plate elevation of the energy dissipation unit (2) is lower than the bottom plate elevation of the main flood discharge channel (01). Ecological water conveyance unit (3), the ecological water conveyance unit (3) includes ecological water discharge pipe (31), the ecological water discharge pipe (31) is buried below the bottom plate of the flood discharge tunnel (1), and the outlet end of the ecological water discharge pipe (31) is connected to the interior of the energy dissipation unit (2); The connecting unit (4) is located on the shared water-retaining sidewall (11) and is used to introduce the ecological water flow after the first-stage energy dissipation in the energy dissipation unit (2) into the main flood discharge channel (01) and merge with the main flood discharge flow in the main flood discharge channel (01) for secondary coordinated energy dissipation.

2. The combined energy dissipation system for flood discharge and ecological water release according to claim 1, characterized in that, The reserved cavity is set between the water-retaining sidewall (11) on the side away from the main body of the dam and the surrounding rock of the mountain. The energy dissipation unit (2) is arranged in an integral connection with the flood discharge and emptying tunnel (1) by sharing the water-retaining sidewall (11) on the side away from the main body of the dam.

3. The combined energy dissipation system for flood discharge and ecological water release according to claim 2, characterized in that, The ecological water conveyance unit (3) also includes a flow control device (32), which is located at the inlet end of the ecological water discharge pipe (31) and is used to adjust the water flow of the ecological water discharge pipe (31) according to the downstream ecological flow demand.

4. The combined energy dissipation system for flood discharge and ecological water release according to claim 3, characterized in that, The ecological water discharge pipe (31) is laid along the tunnel axis of the flood discharge tunnel (1) and along the longitudinal slope of the flood discharge tunnel (1).

5. The combined energy dissipation system for flood discharge and ecological water release according to claim 1, characterized in that, When the space below the bottom plate of the flood discharge tunnel (1) is limited, the ecological water discharge pipe (31) is buried inside the wall of the shared water-retaining side wall (11). The pipe body of the ecological water discharge pipe (31) is laid horizontally at the same height, and the ecological water discharge pipe (31) passes through the outside of the water-retaining side wall (11) and is connected to the cavity energy dissipation unit (2) below the external short pipe.

6. The combined energy dissipation system for flood discharge and ecological water release according to claim 1, characterized in that, The connecting unit (4) consists of multiple overflow holes evenly distributed on the shared vertical sidewall. Each overflow hole penetrates the water-retaining sidewall (11). The bottom elevation of the overflow hole is lower than the normal operating water level of the energy dissipation unit (2), and the water flow direction of the overflow hole is consistent with the flow direction of the main flood discharge channel (01).

7. The combined energy dissipation system for flood discharge and ecological water release according to claim 1, characterized in that, The connecting unit (4) is a curved overflow weir installed on the shared water-retaining sidewall (11), and the crest elevation of the curved overflow weir is lower than the normal operating water level of the energy dissipation unit (2).

8. The combined energy dissipation system for flood discharge and ecological water release according to claim 1, characterized in that, The cavity energy dissipation unit (2) is an energy dissipation pool structure.

9. The combined energy dissipation system for flood discharge and ecological water release according to claim 8, characterized in that, The cavity energy dissipation unit (2) is equipped with energy dissipation blocks and / or energy dissipation grooves as auxiliary energy dissipation components.

10. The combined energy dissipation system for flood discharge and ecological water release according to claim 1, characterized in that, The stilling basin and the water-retaining sidewall (11) are integrally cast concrete structures; the downstream of the main flood discharge channel (01) is provided with an outlet energy dissipation facility. After the ecological water flow introduced through the connecting unit (4) merges with the main flood discharge channel, they jointly conduct secondary coordinated energy dissipation through the outlet energy dissipation facility.

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