Tunnel structure capable of weakening water fins and shock waves

Abstract

The utility model provides a tunnel structure capable of weakening water fins and shock waves, and relates to the technical field of flood discharge tunnel hydraulic energy dissipation, the tunnel structure comprises a flood discharge tunnel, the flood discharge tunnel comprises a top arch, a straight wall is arranged at the bottom end of the top arch, and a bottom plate is arranged at the bottom end of the straight wall; the fin eliminating beams are symmetrically arranged on the straight wall about the central axis of the section of the flood discharging tunnel in the length direction of the flood discharging tunnel, the bottom faces of the fin eliminating beams are arc-shaped inwards-concave faces, and the arc-shaped inwards-concave faces are arranged in the water flow direction; and the section of the arc-shaped inner concave surface is a quarter arc. Water fins and shock waves in the tunnel can be effectively weakened, sufficient ventilation in the tunnel is ensured, cavitation erosion and cavitation in the tunnel are effectively prevented, and stability and safety of the structure of the tunnel are guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of hydraulic flood discharge and energy dissipation in flood discharge tunnels, in particular to a tunnel structure for weakening water wings and shock waves. Background Art

[0002] At present, deep-hole flood discharge and emptying tunnels are set up in hydropower and water conservancy projects to discharge floods and empty reservoirs for maintenance. However, for such hydraulic structures, the actual water flow pattern in the tunnel is relatively complex during flood discharge or emptying, and there will be certain differences with the results of hydraulic model tests. It is easy to produce water wing phenomenon in a certain section of the tunnel. When the water wing gathers, shock waves are generated. In the long run, this kind of mixed water flow pattern will cause cavitation damage to the tunnel structure, affecting the long-term safe operation of the tunnel. Utility Model Content

[0003] The utility model provides a tunnel structure for weakening water wings and shock waves. The purpose is to target the gradually expanding or suddenly expanding cavern sections in the tunnel where water wings are easily generated. After adopting the new tunnel structure, the water wing phenomenon in the tunnel is significantly weakened, ensuring that the clear space area and ventilation volume at the top of the tunnel meet the requirements of the specifications, and also reducing the possibility of generating shock waves, eliminating the hidden danger of cavitation of the tunnel.

[0004] The utility model provides the following technical solutions to achieve the above objectives:

[0005] A tunnel structure for weakening water wings and shock waves comprises a flood discharge tunnel, wherein the flood discharge tunnel comprises a top arch, a straight wall is arranged at the bottom end of the top arch, and a bottom plate is arranged at the bottom end of the straight wall; along the length direction of the flood discharge tunnel, wing-eliminating beams are symmetrically arranged on the straight wall about the central axis of the cross section of the flood discharge tunnel, the bottom surface of the wing-eliminating beam is an arc-shaped inner concave surface, and the arc-shaped inner concave surface is arranged toward the water flow direction; the cross section of the arc-shaped inner concave surface is one eighth of a circular arc.

[0006] Furthermore, the height of the fin-eliminating beam from the bottom plate is equal to the aerated water depth.

[0007] Furthermore, the clearance height between the wing-eliminating beam and the top arch satisfies that the clearance margin area where the clearance height is located is 25% of the upper limit value specified in the spillway design specification.

[0008] Furthermore, the design height of the fin-eliminating beam is determined according to the cross-sectional dimensions of the tunnel and meets the structural safety design requirements.

[0009] Furthermore, the starting point of the wing-eliminating beam is located at the end of the gradual transition section of the flood discharge tunnel.

[0010] Furthermore, the length of the fin-eliminating beam is equal to the length of the tunnel transition section.

[0011] Furthermore, the wing-eliminating beam is provided with a slope along the length direction of the spillway tunnel, and the slope and the slope direction of the wing-eliminating beam are consistent with the slope and the slope direction of the spillway tunnel.

[0012] Beneficial Effects

[0013] Compared with the prior art, the utility model has the following beneficial effects:

[0014] The utility model has a unique and novel structural design, is easy and fast to construct, and has excellent stability. During flood discharge or emptying, it can effectively weaken the water wings and shock waves in the tunnel, ensure sufficient ventilation in the tunnel, and effectively prevent cavitation erosion in the cave, thereby ensuring the stability and safety of the cave structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below only relate to some embodiments of the utility model, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor.

[0016] Figure 1 This is a schematic diagram of the cross-sectional structure of the utility model;

[0017] Figure 2 This is a schematic diagram of the longitudinal section structure of the utility model;

[0018] Figure 3 This is a schematic diagram of the top view structure of the utility model;

[0019] Figure 4 The schematic diagram of water wing flow direction in the tunnel when no wing-eliminating beam is installed Figure 1 ;

[0020] Figure 5 Illustration of the water wing flow direction in the tunnel when setting the wing-eliminating beam Figure 1 ;

[0021] Figure 6 The schematic diagram of water wing flow direction in the tunnel when no wing-eliminating beam is installed Figure 2 ;

[0022] Figure 7 Illustration of the water wing flow direction in the tunnel when setting the wing-eliminating beam Figure 2 ;

[0023] Figure symbols: 1-top arch; 2-vertical wall; 3-bottom plate; 4-elevated wing beam; L1-length of the gradual section of the spillway tunnel; L2-length of the elevated wing beam; i0-tunnel bottom slope; i1-slope of the elevated wing beam; H1-height of the elevated wing beam and bottom plate; H2-design height of the elevated wing beam; H3-clearance height. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiment of the present invention.

[0025] It should be noted that in the present invention: the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or apparatuses; the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside", "outside", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like are based on the directions or positional relationships shown in the drawings. These The terms are mainly used to better describe the utility model and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation; the terms "first", "second", etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence; the terms "install", "set", "provided with", "connected", "connected", "sleeved", etc. should be understood in a broad sense; for example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be an internal connection between two devices, elements or components. In addition, some terms can be used to express other meanings in addition to indicating orientation or positional relationships. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For ordinary technicians in this field, the specific meanings of these terms in the utility model can be understood according to specific circumstances.

[0026] Embodiment. A tunnel structure for weakening water wings and shock waves, the structure is referenced Figures 1 to 3 , including a spillway tunnel, the spillway tunnel includes a top arch 1, a straight wall 2 is arranged at the bottom end of the top arch 1, and a bottom plate 3 is arranged at the bottom end of the straight wall 2; along the length direction of the spillway tunnel, a wing-eliminating beam 4 is symmetrically arranged on the straight wall 2 about the central axis of the spillway tunnel section, the bottom surface of the wing-eliminating beam 4 is an arc-shaped inner concave surface, and the arc-shaped inner concave surface is arranged toward the water flow direction; the cross-section of the arc-shaped inner concave surface is one-eighth of a circular arc.

[0027] The height of the fin-removing beam 4 from the bottom plate 3 is equal to the calculated aerated water depth. The height H1 of the fin-removing beam 4 from the bottom plate 3: According to the energy equation in the "Spillway Design Code NB∕T10867-2021", the water surface line is calculated to obtain the clear water depth, and the aerated water depth is obtained according to the aerated water depth calculation formula. Since the aerated water depth is conservative and greater than the actual operating water depth, the height between the fin-removing beam and the bottom plate is the aerated water depth. The height H1 of the fin-removing beam 4 from the bottom plate 3 is equal to the aerated water depth setting, which can ensure that the water flow will not collide with the cross section of the fin-removing beam 4 when entering the starting point of the fin-removing beam 4; if the actual water depth is greater than the height of the fin-removing beam 4, the high-speed water flow will collide with the cross section of the fin-removing beam 4. Flow turbulence will occur, aggravating cavitation damage.

[0028] The clearance height H3 between the wing-eliminating beam 4 and the top arch 1 satisfies that the clearance margin area where the clearance height is located is 25% of the upper limit value specified in the spillway design specification.

[0029] The design height H2 of the fin-eliminating beam 4 depends on the cross-sectional dimensions of the tunnel and meets the structural safety design requirements.

[0030] The setting starting point of the fin-removing beam 4 is located at the end of the gradual section of the flood discharge tunnel. The tunnel has a gradual change in the flow section after the water intake tower, and the gradual change length is L1. At the same time, the distance between the fin-removing beam 4 and the water intake tower is also L1, that is, the fin-removing beam 4 is set at the end of the gradual section of the tunnel. The setting length of the fin-removing beam 4 is equal to the length of the gradual section of the tunnel. The horizontal length of the fin-removing beam 4 is L2, and the horizontal length of the fin-removing beam 4 is the length of the gradual section of the tunnel, that is, L2=L1. A sudden expansion and sudden drop aeration sill structure is generally set in the water intake tower of the spillway, and the development of the water wing is mainly affected by the sudden expansion width of the aeration sill, the gradual expansion angle and the bottom slope of the tunnel. After the sudden expansion width and the bottom slope are determined, it is found when designing the gradual expansion angle that the upward length of the water wing is basically equivalent to the length in the direction of the water flow corresponding to the gradual expansion angle. Therefore, the horizontal length of the wing-eliminating beam 4 is set equal to the length of the gradual change section of the tunnel. When the water flows through this length range, the water wing develops along the side wall to the bottom plate, and no water wing invading the clear area will be formed along the straight wall 2.

[0031] The wing-removing beam 4 is provided with a slope along the length direction of the flood discharge tunnel, and the slope and the slope direction of the wing-removing beam 4 are consistent with the slope and the slope direction of the flood discharge tunnel. i0 is the bottom slope of the tunnel, i1 is the slope of the wing-removing beam, and i0=i1.

[0032] The working principle and use method of the utility model are as follows: a fin-eliminating beam 4 is arranged at the junction of the side wall and the top arch of the flood discharge tunnel, and the arc-shaped inner concave surface of the fin-eliminating beam 4 is arranged toward the water flow direction to prevent the water fins from climbing along the straight wall 2, and ensure that the water fins on both sides converge toward the center along the arc. During the process of converging at the center, the water fins on both sides collide with each other and dissipate energy, which is not conducive to the formation of shock waves; Figures 4 to 7As shown in the figure, after the fin-eliminating beam is installed, the water fin in the tunnel is obviously lowered, and the water flow height behind the fin-eliminating beam is correspondingly reduced, which basically controls the water surface line at the straight wall part, ensuring the clear area of ​​the top arch, thereby ensuring sufficient ventilation.

[0033] Obviously, the above is only a part of the embodiments of the utility model, not all of the embodiments. The above embodiments are not used to limit the utility model. For those skilled in the art, the utility model can have various changes and variations. Any combination, modification, equivalent replacement, improvement and all other embodiments that can be made by ordinary technicians in the field within the spirit and principle of the utility model should be within the protection scope of the utility model.

Claims

1. A tunnel structure for weakening water wings and shock waves, including a flood discharge tunnel, characterized in that: The flood discharge tunnel comprises a top arch (1), a straight wall (2) is arranged at the bottom end of the top arch (1), and a bottom plate (3) is arranged at the bottom end of the straight wall (2); along the length direction of the flood discharge tunnel, a fin-eliminating beam (4) is symmetrically arranged on the straight wall (2) about the central axis of the cross section of the flood discharge tunnel, the bottom surface of the fin-eliminating beam (4) is an arc-shaped inner concave surface, and the arc-shaped inner concave surface is arranged toward the direction of water flow; the cross section of the arc-shaped inner concave surface is one eighth of a circular arc.

2. The tunnel structure for weakening water wings and shock waves according to claim 1, characterized in that: The height of the fin-eliminating beam (4) from the bottom plate (3) is equal to the aerated water depth.

3. The tunnel structure for weakening water wings and shock waves according to claim 1, characterized in that: The clearance height between the wing-eliminating beam (4) and the top arch (1) satisfies that the clearance margin area where the clearance height is located is 25% of the upper limit value specified in the spillway design specification.

4. The tunnel structure for weakening water wings and shock waves according to claim 1, characterized in that: The design height of the fin-eliminating beam (4) is determined according to the cross-sectional dimensions of the tunnel and meets the structural safety design requirements.

5. The tunnel structure for weakening water wings and shock waves according to claim 1, characterized in that: The starting point of the fin-eliminating beam (4) is located at the end of the gradual transition section of the flood discharge tunnel.

6. The tunnel structure for weakening water wings and shock waves according to claim 1, characterized in that: The arrangement length of the fin-eliminating beam (4) is equal to the length of the tunnel transition section.

7. The tunnel structure for weakening water wings and shock waves according to claim 5, characterized in that: The wing-eliminating beam (4) is provided with a slope along the length direction of the flood discharge tunnel, and the slope and the slope direction of the wing-eliminating beam (4) are consistent with the slope and the slope direction of the flood discharge tunnel.

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