Power-reducing pond

Abstract

This application relates to a stilling basin. The stilling basin includes a bottom plate, a first contracting body, and a second contracting body. The bottom plate includes a steep slope and a horizontal section located at the downstream end of the steep slope. The first and second contracting bodies are symmetrically arranged on both sides of the steep slope along its width, and the distance between the first and second contracting bodies gradually decreases along the direction of water flow. By adding the first and second contracting bodies to the steep slope of the bottom plate, the water depth on the steep slope can be increased, allowing it to form a conjugate relationship with the water depth of the horizontal section of the stilling basin. This enables the downstream flow to form a good energy-dissipating hydraulic jump in the stilling basin. Thus, without increasing the size of the stilling basin, it can effectively dissipate energy from both small and large flow rates of downstream water, and has a wide range of applications.

Description

Technical Field

[0001] This application relates to the field of hydraulic engineering technology, and in particular to a stilling basin. Background Technology

[0002] The stilling basin is a common structure in spillway systems. Its main function is to induce a hydraulic jump in the water flow, thereby dissipating the residual energy carried by the upstream flow and preventing excessive water energy from causing unnecessary scouring damage to the spillway system, related structures, or the river channel. Under normal conditions, the design of the stilling basin and the selection of relevant characteristic parameters are based on the maximum flow rate of the spillway and related parameters of the spillway, utilizing the conjugate relationship at the occurrence of the hydraulic jump. However, in practice, due to the influence of various factors such as site conditions, topographic and geological conditions, and project investment, the actual excavation depth and length of the stilling basin often fail to fully meet the design requirements. In this case, the upstream flow cannot form an ideal hydraulic jump in the stilling basin, resulting in low energy dissipation efficiency and failing to meet the required energy dissipation rate, which can adversely affect the safety of downstream structures. Although setting a tail sill at the end of the stilling basin can raise the water level and increase the water depth of the stilling basin to a certain extent, thus improving the energy dissipation effect of the stilling basin, it will also increase the water level difference between the stilling basin and the downstream channel, increase the instability of the water flow when it enters the downstream channel from the stilling basin, and increase the risk of the water flow overflowing the side wall, which is also detrimental to the safety of the downstream channel. Summary of the Invention

[0003] Therefore, it is necessary to provide a stilling basin to address the above problems.

[0004] A stilling basin includes a bottom plate, a first contractile body, and a second contractile body;

[0005] The base plate includes a steep slope and a horizontal section located at the downstream end of the steep slope. The first contractile body and the second contractile body are symmetrically arranged on both sides of the steep slope along the width direction, wherein the distance between the first contractile body and the second contractile body gradually decreases along the water flow direction.

[0006] In one embodiment, the height of the upstream surfaces of the first and second contractile bodies gradually increases along the direction of water flow, wherein the height of the upstream ends of the first and second contractile bodies is greater than 0.

[0007] In one embodiment, the surface of the first contractile body and / or the second contractile body away from the bottom plate is formed by connecting points A, D and C. Points A and C are arranged sequentially along the water flow direction, and point D is arranged on the bottom plate. The surface formed by connecting points A, C, the projection point A' of point A on the bottom plate and the projection point C' of point C on the bottom plate constitutes the water-facing surface.

[0008] In one embodiment, the height H of the upstream end of the water-facing surface 11 The steep slope section has a normal water depth h when passing through the frequent flow. m The same, where h m It is calculated using the following formula (1):

[0009]

[0010] In the above formula, n refers to the roughness of the steep slope, J refers to the slope of the steep slope, B refers to the width of the upstream end of the steep slope, and Q... m This refers to the frequently encountered flow rate.

[0011] In one embodiment, the height H of the downstream end of the water-facing surface 12 The following formulas (2) to (4) are used to calculate the following:

[0012]

[0013] h"=h2+S (3)

[0014] H 12 =h' (4)

[0015] In the above formula, h” refers to the post-jump water depth in the stilling basin, h’ refers to the pre-jump water depth that should be reached on the steep slope corresponding to h”, B’ refers to the width of the horizontal section, h2 refers to the water depth of the downstream channel of the stilling basin, S refers to the dredging depth of the stilling basin, and g refers to the gravitational acceleration.

[0016] In one embodiment, the distance b2 between the first contractile body and the second contractile body at the downstream end is calculated by the following formula (5):

[0017]

[0018] In one embodiment, the width b1 of the first contractile body and / or the second contractile body at the downstream end should satisfy the following formula (6):

[0019] b2+2b1

[0020] In one embodiment, the steep slope section includes a channel section, a contraction section and a diffusion section arranged sequentially along the water flow direction, wherein the first contraction body and the second contraction body are disposed on the contraction section;

[0021] Wherein, the length L of the diversion channel section 11 The length L of the contraction section 12 and the length L of the diffusion section 13 The following formulas (7) to (9) are used to calculate:​

[0022] L 11 ≥5h m (7)

[0023]

[0024] L 13 =(2~3)h" (9)

[0025] In the above formula, α refers to the unilateral contraction angle of the first contractile body and / or the second contractile body.

[0026] In one embodiment, the slope of the steep section is 1:4 to 1:3.

[0027] In one embodiment, the stilling basin further includes sidewalls disposed on both sides of the base plate along the width direction, the height H of the sidewalls being calculated by the following formula (10):

[0028]

[0029] Where Q refers to the maximum flow rate that the stilling basin may pass through, and H0 refers to the superelevation safety level of the project.

[0030] When the flow rate is not greater than the normal flow rate, the downstream water flow will pass through the steep slope of the stilling basin. At this time, the first and second contraction bodies on both sides of the steep slope along the width direction will squeeze the downstream water flow, causing the water level of the downstream water flow to increase and the water depth to increase. This makes it easy to form a conjugate relationship with the downstream water depth, so that the water flow forms a good energy dissipation hydraulic jump in the stilling basin, resulting in high energy dissipation efficiency.

[0031] When encountering an extraordinary flood, the large-volume downstream flow passes through the steep slope of the stilling basin. The water flow between the first and second contracting sections still forms an energy-dissipating hydraulic jump within the stilling basin. The two streams overflowing from the tops of the first and second contracting sections fall along their respective structures into the stilling basin areas outside the sections, mixing and dissipating energy. Thus, the energy dissipation areas of different water streams are not the same, effectively achieving dispersed energy dissipation of the incoming water and significantly reducing the energy dissipation pressure at the downstream horizontal section of the stilling basin, thus realizing the full utilization of the stilling basin's energy-dissipating water. It should be noted that when the water overflows from the tops of the first and second contracting sections, the length of the tops of these sections is longitudinally elongated along the flow direction. This significantly lengthens the flow area, especially the flow surface near the sidewalls, thus reducing the increase in water level near the sidewalls. This effectively reduces the height of the sidewalls or the probability of water droplets splashing outside the stilling basin structure.

[0032] As can be seen, the stilling basin provided in this application can increase the water depth on the steep slope by adding a first contraction body and a second contraction body to the bottom plate, so that it can form a conjugate relationship with the water depth of the horizontal part of the stilling basin. This allows the downstream water flow to form a good energy dissipation hydraulic jump in the stilling basin. In this way, it can effectively dissipate energy for both small and large flow rates of downstream water flow without increasing the size of the stilling basin, and has the characteristics of wide applicability. Attached Figure Description

[0033] Figure 1 This is a top view of a stilling basin provided in an embodiment of this application.

[0034] Figure 2 This is a side view of a stilling basin according to an embodiment of this application.

[0035] Figure 3 This is a three-dimensional structural diagram of a first or second contractile body provided in an embodiment of this application.

[0036] Figure 4 It means Figure 1 A magnified view of a portion of the image.

[0037] The labels in the attached diagram are explained as follows:

[0038] 10. Stilling basin; 100. Base plate; 110. Steep slope section; 120. Horizontal section; 210. First contraction body; 220. Second contraction body; 300. Side wall. Detailed Implementation

[0039] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0040] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0041] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0042] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0043] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0044] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0045] See Figure 1 and Figure 2An embodiment of this application provides a stilling basin 10. The stilling basin 10 includes a side wall 300, a bottom plate 100, a first contracting body 210, and a second contracting body 220. The side wall 300 is disposed on both sides of the bottom plate 100 along the width direction. The bottom plate 100 includes a steep slope portion 110 and a horizontal portion 120 disposed at the downstream end of the steep slope portion 110. The first contracting body 210 and the second contracting body 220 are symmetrically disposed on both sides of the steep slope portion 110 along the width direction, wherein the distance between the first contracting body 210 and the second contracting body 220 gradually decreases along the water flow direction.

[0046] It is understandable that there are two sidewalls 300, that is, one sidewall 300 is set on each side of the base plate 100 along the width direction.

[0047] When the flow rate is not greater than the normal flow rate, the outflow will flow through the steep slope 110 of the stilling basin 10. At this time, the first contraction body 210 and the second contraction body 220 on both sides of the steep slope 110 along the width direction will squeeze the outflow, increasing the water level of the outflow, which is equivalent to increasing the water depth of the steep slope 110. This makes it easy to form a conjugate relationship with the water depth of the horizontal part of the stilling basin, so that the water flow forms a good energy dissipation hydraulic jump in the stilling basin, resulting in high energy dissipation efficiency.

[0048] When encountering an extraordinary flood, the large-volume downstream flow will pass through the steep slope 110 of the stilling basin 10. The water flow between the first contraction body 210 and the second contraction body 220 will still form an energy-dissipating hydraulic jump in the stilling basin 10. The two streams of water overflowing from the top of the first contraction body 210 and the second contraction body 220 will fall along the first contraction body structure 210 and the second contraction body structure 220 respectively into the stilling basin 10 outside the corresponding contraction body and mix with the water there for energy dissipation. It can be seen that the energy dissipation areas of different water streams are not the same, which effectively achieves the dispersed energy dissipation of the incoming water body, effectively reduces the energy dissipation pressure of the downstream horizontal section 120 of the stilling basin, and realizes the full utilization of the energy-dissipating water body of the stilling basin 10. It should be noted that when water overflows from the top of the first contraction body 210 and the second contraction body 220, the length of the top of the first and second contraction bodies is longitudinally elongated along the water flow direction. The flow area of ​​the water flow, especially the flow surface near the side wall 300, is significantly elongated. Therefore, the increase in water level near the side wall 300 is significantly reduced, which can effectively reduce the height of the side wall 300 or reduce the probability of water droplets splashing to the outside of the stilling pool structure 10.

[0049] As can be seen, the stilling basin 10 provided in this application can increase the water depth on the steep slope 110 by adding a first contraction body 210 and a second contraction body 220 to the steep slope 110 of the bottom plate 100, so that it can form a conjugate relationship with the water depth of the horizontal part 120 of the stilling basin. This allows the downstream water flow to form a good energy dissipation hydraulic jump in the stilling basin 10. In this way, without increasing the size of the stilling basin 10, it can effectively dissipate energy for both small and large flow rates of downstream water flow, and has the characteristics of wide applicability.

[0050] In some embodiments of this application, the heights of the water-facing surfaces of the first contraction body 210 and the second contraction body 220 gradually increase along the direction of water flow, wherein the heights of the upstream ends of both the first contraction body 210 and the second contraction body 220 are greater than 0. This setting of the heights of the water-facing surfaces of the first contraction body 210 and the second contraction body 220 effectively compresses the water flow between them, effectively increasing the water depth on the steep slope 110. This facilitates a conjugate relationship with the downstream water depth, resulting in a good energy-dissipating hydraulic jump in the stilling basin 10.

[0051] It should be noted that the water-facing surface of the first contraction body 210 refers to the surface of the first contraction body 210 that is close to the second contraction body 220, and the water-facing surface of the second contraction body 220 refers to the surface of the second contraction body 220 that is close to the first contraction body 210. The height of the water-facing surface refers to the length of the water-facing surface in the direction perpendicular to the ground. The height of the upstream end of the first contraction body 210 refers to the length of the upstream end of the first contraction body 210 in the direction perpendicular to the ground, and the height of the upstream end of the second contraction body 220 refers to the length of the upstream end of the second contraction body 220 in the direction perpendicular to the ground.

[0052] The water-facing surface of the first contractile body 210 and / or the water-facing surface of the second contractile body 220 can be a plane or an arc surface curved toward the corresponding sidewall 300 (i.e., Figure 1 (The dashed lines shown in the diagram). As an example, the water-facing surfaces of the first contraction body 210 and the second contraction body 220 are both planar, or the water-facing surfaces of the first contraction body 210 and the second contraction body 220 are both curved surfaces.

[0053] Specifically, see Figure 1 The surface of the first contraction body 210 and / or the second contraction body 220 away from the bottom plate 100 is formed by connecting points A, D, and C. Points A and C are sequentially arranged along the water flow direction, and point D is located on the bottom plate 100. (See also...) Figure 2 and Figure 3The surface formed by connecting points A, C, the projection point A' of point A on the base plate 100, and the projection point C' of point C on the base plate 100 constitutes the water-facing surface. Setting point D on the base plate 100 facilitates the outflow of large-volume downstream water from the AC side to the outside of the first contraction body 210 and the second contraction body 220, ensuring the smooth flow of large-volume water and also ensuring the structural stability of the first contraction body 210 and the second contraction body 220.

[0054] Optionally, the water-facing surface, surface AA'D, and surface CC'D are perpendicular to the ground. Considering that the weight of the first and second contractile bodies is perpendicular to the ground, if the water-facing surface, surface AA'D, and surface CC'D are perpendicular to the steep slope 110 of the base plate 100, the water-facing surface, surface AA'D, and surface CC'D will be prone to instability due to the steepness of the slope 110.

[0055] It is understandable that the lines connecting points A and A' and C and C' are both perpendicular to the ground, and the length of the line connecting points A and A' is less than the length of the line connecting points C and C'.

[0056] Among them, the height H at the upstream end of the water-facing side 11 (i.e., the length of the line connecting point A and point A') and the normal water depth h of the steep slope 110 when passing through the common flow. m The same principle applies to ensure that the water flow forms a good hydraulic jump in the downstream stilling basin 10 when the discharge is at the normal flow rate, where h m It is calculated using the following formula:

[0057]

[0058] In equation (1) above, n refers to the roughness of the steep slope 110, J refers to the slope of the steep slope 110, B refers to the width of the upstream end of the steep slope 110, and Q... m This refers to the frequently encountered flow rate.

[0059] The roughness coefficient n of the steep slope section 110 is mainly related to the material of the stilling basin 10. For example, when the stilling basin 10 is made of concrete, n can be taken as 0.015; when the stilling basin 10 is made of masonry, n can be taken as 0.025. The width B of the upstream end of the steep slope section 110 is set according to the site conditions and can be directly selected with reference to the current specifications. The common flow rate Q m It is a flow rate with a relatively high probability of occurrence, which can be estimated and determined by combining engineering design data and hydrological data.

[0060] Regarding the slope J of the steep slope section 110 (i.e., the ratio of the height difference between the upstream and downstream ends of the steep slope section 110 to its length), it can be taken as 1:4 to 1:3. If the slope is too gentle, an energy-dissipating hydraulic jump can usually be formed in the stilling basin 10, so adding the first contraction body 210 and the second contraction body 220 is not very meaningful, and may even aggravate the water level fluctuation in the stilling basin 10. If the slope is too steep, due to the excessive flow velocity, the water jet will rise too high after being contracted by the contraction body and will be difficult to control. If the construction is asymmetrical, the water jet will deviate to one side. If it is not well controlled, the rising water jet may protrude beyond the sidewall 300.

[0061] The height H of the downstream end of the water-facing side 12 (i.e., the length of the line connecting point C and point C') can be obtained through the conjugate relationship when the stilling basin 10 forms a hydraulic jump, and can be specifically calculated using the following formulas (2) to (4):

[0062]

[0063] h"=h2+S (3)

[0064] H 12 =h' (4)

[0065] In the above formula, h” refers to the post-jump water depth in the stilling basin 10, h’ refers to the pre-jump water depth that should be reached on the steep slope 110 corresponding to h”, B’ refers to the width of the horizontal section 120, h2 refers to the water depth of the downstream channel of the stilling basin 10, S refers to the dredging depth of the stilling basin 10, and g refers to the gravitational acceleration.

[0066] It should be noted here that, as can be seen from the method of determining the height of the upstream and downstream ends as described above, this application calculates the water depth required under the target flow condition based on the water depth of the horizontal part 120 in the stilling basin 10, so as to form a conjugate condition with the downstream water depth.

[0067] The distance b2 between the first contractile body 210 and the second contractile body 220 at the downstream end is calculated by the following formula (5):

[0068]

[0069] The width b1 at the downstream end of the first contractile body 210 or / and the second contractile body 220 should satisfy the following formula (6):

[0070] b2+2b1

[0071] By setting the width b1 of the first contraction body 210 and / or the second contraction body 220 at the downstream end in this way, it can be ensured that there is sufficient cavity on the outside of the first contraction body 210 and the second contraction body 220 for leakage and air replenishment. ​

[0072] In some embodiments of this application, the steep slope 110 includes a channel section, a contraction section, and a diffusion section arranged sequentially along the water flow direction, with a first contraction body 210 and a second contraction body 220 disposed on the contraction section. It should be noted that the first contraction body 210 and the second contraction body 220 extend through the entire length of the contraction section, and the width of the channel section refers to the width of the upstream end of the steep slope 110.

[0073] The width of the contraction section, the diffusion section and the horizontal section 120 are the same and greater than the width of the channel section, by at least 20cm. This allows for the formation of a protruding sill with a width of at least 10cm on both sides of the first and second contraction bodies. When a large discharge occurs and passes through the top of the first and second contraction bodies, lateral expansion cavities can be formed on both sides to ensure the stability of the water tongue pattern that overflows the top of the first and second contraction bodies.

[0074] Length L of the irrigation canal section 11 Length L of the contraction segment 12 and the length L of the diffusion section 13 The following formulas (7) to (9) are used to calculate:

[0075] L 11 ≥5h m (7)

[0076]

[0077] L 13 =(2~3)h" (9)

[0078] In the above formula, α is as follows Figure 4 As shown, this refers to the unilateral contraction angle of the first contraction body 210 and / or the second contraction body 220.

[0079] The value of tanα can range from 1 / 5 to 1 / 4. When this value is too large, the water flow contracts too rapidly and is difficult to control; when this value is too small, with a fixed width at the downstream end of the first and second contraction bodies, a longer L is required. 12 It requires more space.

[0080] In some embodiments of this application, the height H of the sidewall 300 is calculated using the following formula (10):

[0081]

[0082] Where Q refers to the maximum flow rate that the stilling basin 10 may pass through, and H0 refers to the superelevation safety level of the project.

[0083] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0084] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A stilling basin, characterized in that, Includes a base plate, a first contractile body, and a second contractile body; The bottom plate includes a steep slope and a horizontal section located at the downstream end of the steep slope. The first contraction body and the second contraction body are symmetrically arranged on both sides of the steep slope along the width direction, wherein the distance between the first contraction body and the second contraction body gradually decreases along the water flow direction. The height of the upstream surfaces of the first and second contractile bodies gradually increases along the direction of water flow, wherein the height of the upstream ends of the first and second contractile bodies is greater than 0. The surface of the first contractile body and / or the second contractile body away from the base plate is formed by connecting points A, D, and C. Points A and C are sequentially arranged along the direction of water flow, and point D is located on the base plate. The line connecting point A and its projection point A' on the base plate, and the line connecting point C and its projection point C' on the base plate, are both perpendicular to the ground, and A'A <C'C; Water flows through the first and second contraction bodies, and some water overflows from the top of the first and second contraction bodies, falling into the stilling pool along the outer side of the first and second contraction bodies respectively, and mixing with the water in the corresponding area to dissipate energy, thereby achieving dispersed energy dissipation of the incoming water and reducing the energy dissipation pressure at the downstream horizontal part of the stilling pool.

2. The stilling basin according to claim 1, characterized in that, The surface formed by connecting points A, C, the projection point A' of point A on the base plate, and the projection point C' of point C on the base plate constitutes the water-facing surface.

3. The stilling basin according to claim 1, characterized in that, The height H of the upstream end of the water-facing surface 11 The steep slope section has a normal water depth h when passing through the frequent flow. m The same, where h m It is calculated using the following formula (1): （1） In the above formula, n refers to the roughness of the steep slope, J refers to the slope of the steep slope, B refers to the width of the upstream end of the steep slope, and Q... m This refers to the frequently encountered flow rate.

4. The stilling basin according to claim 1, characterized in that, The height H of the downstream end of the water-facing surface 12 The following formulas (2) to (4) are used to calculate: （2） （3） （4） In the above formula, h'' refers to the post-jump water depth in the stilling basin, h' refers to the pre-jump water depth that should be reached on the steep slope corresponding to h'', B' refers to the width of the horizontal section, h2 refers to the water depth of the downstream channel of the stilling basin, S refers to the dredging depth of the stilling basin, and g refers to the gravitational acceleration.

5. The stilling basin according to claim 1, characterized in that, The distance b2 between the first contractile body and the second contractile body at the downstream end is calculated by the following formula (5): （5）。 6. The stilling basin according to claim 1, characterized in that, The width b1 of the first contractile body and / or the second contractile body at the downstream end should satisfy the following formula (6): （6）。 7. The stilling basin according to any one of claims 1 to 6, characterized in that, The steep slope section includes a channel section, a contraction section and a diffusion section arranged sequentially along the water flow direction, with the first contraction body and the second contraction body disposed on the contraction section; Wherein, the length L of the diversion channel section 11 The length L of the contraction section 12 and the length L of the diffusion section 13 The following formulas (7) to (9) are used to calculate: （7） （8） （9） In the above formula, α refers to the unilateral contraction angle of the first contractile body and / or the second contractile body.

8. The stilling basin according to any one of claims 1 to 6, characterized in that, The slope of the steep section is 1:4 to 1:

3.

9. The stilling basin according to any one of claims 1 to 6, characterized in that, The stilling basin also includes side walls disposed on both sides of the base plate along the width direction, and the height H of the side walls is calculated by the following formula (10): （10） Where Q refers to the maximum flow rate that the stilling basin may pass through, and H0 refers to the superelevation safety level of the project.

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