Method for setting a permeable structure in a metamorphic integral tidal current and sediment physical model

Abstract

The application discloses a method for setting a water-permeable building in a metamorphic integral tide flow sediment physical model, and relates to the technical field of water conservancy, water transportation and ocean engineering test. The method firstly obtains the relationship between the local water head loss of the water-permeable building and the downstream flow speed water head through the normal water channel test of the water-permeable building section; then the metamorphic water channel test of the water-permeable building section is carried out by adjusting the test section of the water-permeable building, so that the resistance of the adjusted building test section is similar to the resistance characteristics in the normal water channel test, thereby the size of the water-permeable building section in the metamorphic integral tide flow sediment physical model is determined. The application realizes the accurate simulation of the resistance characteristics of the water-permeable building in the metamorphic integral tide flow sediment physical model, and provides a scientific basis for carrying out the engineering design and verification by using the metamorphic integral tide flow sediment physical model.

Description

Technical Field

[0001] This invention relates to the field of physical model testing technology for water conservancy projects, water transport projects and marine engineering, and particularly to a method for setting up permeable structures in a modified overall tidal current sediment physical model. Background Technology

[0002] Compared to traditional structures, permeable structures possess a certain degree of permeability and offer better ecological benefits, leading to their widespread application in water conservancy, water transport, and marine engineering in recent years. Common permeable structures include permeable groynes filled with netting and pebbles, hollow block breakwaters, and interlocking revetments. Using a holistic physical model to study the flow characteristics and sediment erosion / deposition patterns of water-related projects is a crucial method for determining the rationality of the layout of water-related structures and optimizing engineering schemes. In engineering environments such as the Yangtze River and the Jiangsu sea area, the planar dimensions (length, width) are often several times, tens, hundreds, or even thousands of times larger than the vertical dimensions (water depth). In such cases, constructing a holistic physical model according to a normal geometric scale is economically and physically infeasible. Using a modified holistic physical model, which "compresses" the planar extent more significantly and the vertical extent less, allows for the simulation of larger engineering scales within a laboratory space.

[0003] However, in abnormal overall physical models, the resistance distribution changes due to the "distorted" geometry. Therefore, precise terrain shaping and artificial intervention (such as roughening) are needed to compensate for and adjust the resistance, ensuring the overall similarity of water flow and material movement. Compared to traditional impermeable structures, the hydraulic characteristics of permeable structures depend on the accurate simulation of their resistance characteristics. Methods for setting up traditional impermeable structures in abnormal overall physical models cannot be simply transferred to permeable structures. Currently, there are no reports on methods for rationally setting up permeable structures in abnormal overall tidal and sediment physical models. Summary of the Invention

[0004] The problem to be solved by this invention is to provide a method for setting up permeable structures in a modified overall tidal current and sediment physical model, so as to realize the accurate simulation of the resistance characteristics of permeable structures in the modified overall tidal current and sediment physical model, and provide a scientific basis for engineering design and verification using the modified overall tidal current and sediment physical model.

[0005] This invention adopts the following technical solution: a method for setting up permeable structures in a modified overall tidal current sediment physical model, comprising the following steps:

[0006] Step 1: Determine the normal geometric scale of the normal flume test for the cross-section of the permeable structure based on the plane scale and vertical scale of the abnormal overall physical model test;

[0007] Step 2: Based on the cross-sectional dimensions of the permeable structure, the structural dimensions of the permeable structure, and the normal geometric scale of the cross-sectional normal flume test in Step 1, determine the cross-sectional dimensions of the permeable structure and the dimensions of the test structure under each geometric scale in the cross-sectional normal flume test, and fabricate the test structure corresponding to each geometric scale.

[0008] Step 3: Conduct normal flume tests on the cross-sections of permeable structures under various normal geometric scales;

[0009] Step 4: Calculate the local head loss of the permeable structure and the downstream velocity head for each test group of the normal flume test, and draw the relationship between the local head loss of the permeable structure and the downstream velocity head corresponding to the normal flume test.

[0010] Step 5: Based on the cross-sectional dimensions of the permeable structure and the vertical scale of the abnormal overall physical model test, determine the permeable structure cross-section scaled down according to the vertical scale.

[0011] Step 6: Adjust the cross-section of the permeable structure determined in Step 5 to obtain the cross-section of the permeable structure under abnormal test.

[0012] Step 7: Conduct a flow-through abnormal water tank test on the cross-section of the permeable structure;

[0013] Step 8: Calculate the local head loss and downstream velocity head of the permeable structure for each test group of the abnormal flume test, plot the data points of local head loss and downstream velocity head of the permeable structure corresponding to the abnormal flume test, and overlay them on the relationship graph of local head loss and downstream velocity head of the permeable structure obtained from the normal flume test in step 4.

[0014] Step 9: Analyze the degree of agreement between the data points from the abnormal flume test in Step 8 and the relationship between the local head loss of the permeable structure and the downstream velocity head obtained from the normal flume test in Step 4, and make iterative adjustments until the agreement requirement is met.

[0015] Step 10: Use the permeable structure cross-section obtained after adjustment in Step 9 as the permeable structure cross-section in the overall physical model of the abnormal structure.

[0016] Furthermore, in step 1, the planar scale of the abnormal overall physical model experiment is λ. L The vertical scale is λ H The normal geometric scale corresponding to the normal flume test of the water structure cross section is: (n≥1);

[0017] in, ,and ;

[0018] It is necessary to ensure that the scale effect does not affect the test results under the geometric scale λ1. If it is uncertain whether the scale effect will affect the test results under the geometric scale λ1, multiple permeable structure cross-section flow flue tests under different normal scale conditions should be conducted, i.e. (n≥2).

[0019] Furthermore, in step 3, a normal flume test is conducted on the cross-section of the permeable structure under various normal geometric scales. The specific steps are as follows:

[0020] Step 3.1 First, for each geometric scale test, according to the cross-sectional dimensions of the permeable structure corresponding to the geometric scale, use the test structure corresponding to the geometric scale to build the permeable structure in the water tank. The axial direction of the permeable structure is consistent with the width direction of the water tank, that is, the normal direction of the permeable structure cross-section is perpendicular to the water tank, and the permeable structure occupies the entire width of the water tank.

[0021] Step 3.2: By changing the upstream water depth and flow velocity, conduct m measurements of the normal flume test of the permeable structure cross-section. The measurements include the water depth and average flow velocity in the upstream stable section and the downstream stable section of the permeable structure.

[0022] Specifically, during the experiment, if the test structure is lightweight and the permeable structure cannot remain stable in the water flow, auxiliary stabilizing tools (such as wire mesh) are used to fix the permeable structure; if the permeable structure can remain stable in the water flow, then auxiliary stabilizing tools are not required.

[0023] Step 3.3: Repeat steps 3.1 to 3.2 to complete the normal flume test for all permeable structure cross sections with different geometric scales.

[0024] Furthermore, in step 6, when designing the first permeable structure's abnormal test section, the following method is used:

[0025] For the cross-section of a permeable structure that is scaled down vertically according to the abnormal overall physical model, its vertical dimensions are retained while its horizontal dimensions are shortened.

[0026] When the data points of the abnormal flume test deviate below the corresponding point group of the normal flume test, increase the horizontal dimension of the cross section of the abnormal test of the permeable structure.

[0027] When the data points of the abnormal flume test deviate from the corresponding point group of the normal flume test, reduce the horizontal dimension of the cross section of the permeable structure in the abnormal test.

[0028] Furthermore, in steps 4 and 8, the downstream flow velocity head is determined according to... Calculate, where, The average flow velocity in the stable section downstream of the building. It is the acceleration due to gravity;

[0029] Local head loss of permeable structures according to Calculate, where, and These refer to the water depths in the upstream and downstream stable sections of the permeable structure, respectively. The average flow velocity in the stable section upstream of the permeable structure. and These are the upstream and downstream flow velocity kinetic energy correction coefficients, respectively.

[0030] Furthermore, in step 7, the flow-through abnormal water tank test of the permeable structure cross-section is carried out according to the following steps:

[0031] Step 7.1: Based on the abnormal test section of the permeable structure in Step 6, use the test structure corresponding to the vertical scale of the abnormal overall physical model to construct the permeable structure in the water tank. The normal direction of the permeable structure section is perpendicular to the water tank, and the permeable structure occupies the entire width of the water tank.

[0032] Step 7.2: By changing the upstream water depth and flow velocity, conduct k (k≥1) measurements of the permeable structure cross-section through-flow alteration flume. The measurements include the water depth and average flow velocity in the upstream stable section and the downstream stable section of the permeable structure.

[0033] In particular, if a permeable structure cannot remain stable in the water flow, auxiliary stabilizing tools (such as wire mesh) should be used to secure the permeable structure.

[0034] Furthermore, in step 9, the iterative adjustment process is as follows:

[0035] If the data point corresponding to the abnormal flume test is in the same group of data points as the normal flume test, then the permeable structure test section in step 6 will be used in the abnormal overall physical model.

[0036] If the data points corresponding to the abnormal flume test deviate from the point group corresponding to the normal flume test, then modify the test section of the permeable structure and repeat steps 7 to 9 until the data points corresponding to the abnormal flume test and the relationship between the local head loss of the permeable structure and the downstream velocity head obtained from the normal flume test in step 4 meet the preset matching requirements.

[0037] Furthermore, in step 10, the length of the permeable structure in the horizontal direction in the abnormal overall physical model is determined according to the planar scale of the abnormal overall physical model.

[0038] Compared with the prior art, the present invention, employing the above technical solution, has the following technical effects:

[0039] 1. This invention uses normal flume and abnormal flume tests on the cross-section of permeable structures to determine the similarity between the hydraulic resistance of the permeable structure cross-section in the abnormal overall physical model and the normal model, thereby improving the accuracy of water flow simulation and sediment transport simulation in the abnormal overall physical model. It also solves the problem of how to design the cross-section of permeable structures in the abnormal overall physical model and has significant engineering application value.

[0040] 2. This invention is applicable to permeable structures composed of different permeable structures (such as permeable frames, hollow blocks, H-shaped blocks, and interlocking bodies). Attached Figure Description

[0041] Figure 1 This is a flowchart illustrating the steps of setting up permeable structures in the abnormal overall tidal current sediment physical model of the present invention.

[0042] Figure 2 This is a schematic diagram of the cross-section of a permeable structure according to an embodiment of the present invention;

[0043] Figure 3 This is a schematic diagram showing the dimensions of the hollow blocks that make up the permeable structure according to an embodiment of the present invention;

[0044] Figure 4 This is a graph showing the relationship between local head loss of a permeable structure and downstream flow velocity head obtained from a normal flume test in an embodiment of the present invention.

[0045] Figure 5 This is a permeable structure cross-section scaled down vertically according to the abnormal overall physical model in this embodiment of the invention;

[0046] Figure 6 This is the cross-section of the permeable structure after adjustment based on the vertical scale reduction of the permeable structure according to the abnormal overall physical model in this embodiment of the invention;

[0047] Figure 7 This is an overlay diagram showing the relationship between local head loss and downstream velocity head of a permeable structure obtained from the abnormal flume test and the normal flume test in the implementation of this invention. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the application will be further described in detail below with reference to the accompanying drawings. The described embodiments are only a part of the embodiments involved in this invention. All non-innovative embodiments based on these embodiments by other researchers in the art are within the protection scope of this invention. Furthermore, the step numbers in the embodiments of this invention are only set for ease of explanation and do not limit the order of the steps. The execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0049] In one embodiment of the present invention, a port project plans to construct a sand-retaining dike using hollow blocks (the dike crest elevation is higher than the sea surface). Compared with traditional riprap dikes, the hollow block sand-retaining dike has better permeability and is more environmentally friendly to the marine area. To study the flow field characteristics and sand-retaining effect around the hollow block sand-retaining dike, it is necessary to conduct a comprehensive physical model test of tidal currents, waves, and sediment in the project area. Given the wide water surface and shallow water depth in the project area, a modified design will be adopted for the comprehensive physical model.

[0050] In this embodiment, a method for setting up permeable structures in a modified overall tidal sediment physical model is described, such as... Figure 1 As shown, it includes the following steps:

[0051] Step 1: Experiment with the physical model of the abnormal whole, with a plane scale of λ. L and vertical scale λ H The scales are 750 and 75, respectively, with a variation rate of 10. To investigate whether the scale effect affects the test results, normal flume tests of permeable structure cross-sections with four normal geometric scales of 15, 30, 50, and 75 are planned.

[0052] Step 2: The hollow block sand-retaining dike has a crest elevation of +3.0m, a base elevation of -7.0m, and a mean sea level elevation of +1.27m. The dike's cross-section is an isosceles trapezoid, with a crest width of 5m, a base width of 35m, a height of 10m, and a length of 1500m. The cross-section is as follows: Figure 2 As shown.

[0053] The hollow block is a hollow cube with dimensions as shown. Figure 3 As shown, the outer contour of the cube has a side length of 1.8m, the four surrounding rods are 0.35m wide and 1.1m long, and the inner reinforcing triangular rods are 0.2m × 0.2m × 0.35m in size.

[0054] Based on the cross-sectional dimensions of the hollow block sand-retaining dike, the dimensions of the hollow block, and the geometric scales of the cross-sectional normal flume test in step 1 (i.e., 15, 30, 50, and 75), the cross-sectional dimensions of the hollow block sand-retaining dike and the dimensions of the hollow block test blocks under each geometric scale in the cross-sectional normal flume test of the permeable structure are determined, as shown in Tables 1 and 2 below.

[0055] Table 1. Cross-sectional dimensions of hollow block sand-retaining dikes under different normal geometric scale conditions.

[0056]

[0057] Table 2. Dimensions of hollow blocks under different geometric scales

[0058]

[0059] Furthermore, based on the determined hollow block size, a sufficient number of hollow block test blocks are made under different normal geometric scale conditions.

[0060] Specifically, under normal geometric scales of 15, 30, 50, and 75, the number of hollow block test specimens were 270, 540, 900, and 1400, respectively. The hollow block test specimens with scales of 15 and 30 were made of concrete mixed with iron powder, while the hollow block test specimens with scales of 50 and 75 were made of weight-added plastic.

[0061] Step 3: Conduct normal flume tests on the cross-sections of permeable structures at various geometric scales. The specific steps are as follows:

[0062] Step 3.1: First, conduct a test at a geometric scale of 15. According to the cross-sectional dimensions of the permeable structure corresponding to this geometric scale, use the test structure corresponding to this geometric scale to build a hollow block sand-retaining embankment in the water tank. The axial direction of the hollow block sand-retaining embankment is consistent with the width direction of the water tank, that is, the normal direction of the permeable structure cross-section is perpendicular to the water tank, and the permeable structure occupies the entire width of the water tank.

[0063] Step 3.2: Hollow block test blocks with geometric scales of 15 and 30 are made of concrete mixed with iron powder, which can remain stable in water flow. Hollow block test blocks with geometric scales of 50 and 75 are made of weighted plastic. To maintain the stability of the hollow block test blocks in water flow, wire mesh is used to fix the hollow block sand retaining dikes.

[0064] Step 3.3: By changing the upstream water depth and flow velocity, conduct m measurements of the normal flume test of the permeable structure cross-section. The measurements include the water depth and average flow velocity in the upstream stable section and the downstream stable section of the permeable structure.

[0065] Step 3.4: Repeat steps 3.1 to 3.3 to complete the normal flume test for all permeable structure cross sections with different geometric scales. The test measurement results are shown in Table 3.

[0066] Table 3. Test results of permeable structure cross-sections with overflow channels under different geometric scales.

[0067]

[0068] Step 4: Based on the measurement results recorded in Step 3, according to... Calculate the downstream velocity head, based on Calculate the local head loss of permeable structures;

[0069] in, and These refer to the water depths in the upstream and downstream stable sections of the permeable structure, respectively. and These represent the average flow velocity in the upstream and downstream stable sections of a permeable structure, respectively. and These are the upstream and downstream flow velocity kinetic energy correction coefficients, both approximately taken as 1.1.

[0070] The calculated downstream velocity head and local head loss of the permeable structure are shown in Table 3. The relationship between the local head loss of the permeable structure and the downstream velocity head corresponding to the normal flume test is plotted, as shown below. Figure 4 As shown.

[0071] Step 5: Based on the cross-sectional dimensions of the permeable structure and the abnormal overall physical model, test the vertical scale λ. H Determine the cross-section of the permeable structure scaled down to the vertical scale, such as Figure 5 As shown. λ H When the value is 75, the top width of the dike is 6.7cm, the bottom width is 46.7cm, and the height is 13.3cm.

[0072] Step 6: If the permeable structure is constructed according to the permeable structure cross-section determined in Step 5, the sand-blocking dike in the overall physical model will be too large, which will disrupt the overall flow field around the dike. Therefore, the cross-section needs to be modified.

[0073] The cross-sectional dimensions of the permeable structure determined in step 5 were initially modified to a bottom width of 29.3 cm and a top width of 2.7 cm, while keeping the height unchanged. This yielded the cross-section of the permeable structure for the stress test. Figure 6 Interruption surface A.

[0074] Step 7: Conduct a flow-through abnormal flume test on section A of the permeable structure, following these steps:

[0075] Step 7.1: Based on section A, use the test structure corresponding to the vertical scale of the abnormal overall physical model (i.e., the test structure corresponding to the geometric scale 75) to construct a permeable structure in the water tank. The normal direction of the permeable structure section is perpendicular to the water tank, and the permeable structure occupies the entire width of the water tank.

[0076] Step 7.2: Conduct one flume test on the cross-section of the permeable structure by changing the upstream water depth and flow velocity. The measurements include the water depth and average flow velocity in the upstream stable section and the downstream stable section of the permeable structure. During the test, the permeable structure is fixed with wire mesh. The measurement results are shown in Table 4.

[0077] Table 4. Measurement results of cross-sectional water flow channel tests under different permeable structure test conditions.

[0078]

[0079] Step 8: Based on the measurement results recorded in Step 7, according to... Calculate the downstream velocity head, based on Calculate the local head loss of permeable structures;

[0080] in, and These refer to the water depths in the upstream and downstream stable sections of the permeable structure, respectively. and These represent the average flow velocity in the upstream and downstream stable sections of a permeable structure, respectively. and These are the upstream and downstream flow velocity kinetic energy correction coefficients, both approximately taken as 1.1.

[0081] The calculated downstream velocity head and local head loss of the permeable structure are shown in Table 4. The local head loss of the permeable structure and the downstream velocity head data points corresponding to section A are plotted as follows: Figure 7 As shown.

[0082] Step 9 Figure 7 In the middle, the data point of section A is located below the relationship between the local head loss of the permeable structure and the downstream velocity head obtained from the normal flume test in step 4, indicating that the resistance of section A is small and the cross-sectional area needs to be increased.

[0083] Further modify section A to section B, such as Figure 6 The width of the dike top is adjusted to 29.3cm. Steps 7 to 9 are repeated to obtain the local head loss and downstream velocity head data points of the permeable structure corresponding to section B.

[0084] Figure 7 In the middle, the data point of section B is located above the relationship between the local head loss of the permeable structure and the downstream velocity head obtained from the normal flume test in step 4, indicating that the resistance of section B is relatively large and the cross-sectional area needs to be reduced.

[0085] Furthermore, at sections A and B, section C is designed, that is, the width of the embankment crest is modified to 16.0 cm. Steps 7-9 are repeated to obtain the local head loss of the permeable structure and the downstream velocity head data points corresponding to section C.

[0086] Figure 7 In the middle section, the data points of section C are in good agreement with the relationship between the local head loss of the permeable structure and the downstream velocity head obtained from the normal flume test in step 4, indicating that the resistance of section C is appropriate and can be used for the abnormal physical model.

[0087] Step 10: Take the cross section C obtained in Step 9 as the cross section of the hollow block test embankment in the abnormal overall physical model. Its length in the horizontal direction is determined according to the plane scale of the abnormal overall physical model of 750, that is, 1500 / 750=2m.

[0088] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for setting up permeable structures in a modified overall tidal current sediment physical model, characterized in that, Includes the following steps: Step 1: Determine the normal geometric scale of the normal flume test for the cross-section of the permeable structure based on the plane scale and vertical scale of the abnormal overall physical model test; Step 2: Based on the cross-sectional dimensions of the permeable structure, the structural dimensions of the permeable structure, and the normal geometric scale of the cross-sectional normal flume test in Step 1, determine the cross-sectional dimensions of the permeable structure and the dimensions of the test structure under each geometric scale in the cross-sectional normal flume test, and fabricate the test structure corresponding to each geometric scale. Step 3: Conduct normal flume tests on the cross-sections of permeable structures under various normal geometric scales; Step 4: Calculate the local head loss of the permeable structure and the downstream velocity head for each test group of the normal flume test, and draw the relationship between the local head loss of the permeable structure and the downstream velocity head corresponding to the normal flume test. Step 5: Based on the cross-sectional dimensions of the permeable structure and the vertical scale of the abnormal overall physical model test, determine the permeable structure cross-section scaled down according to the vertical scale. Step 6: Adjust the cross-section of the permeable structure determined in Step 5 to obtain the cross-section of the permeable structure under abnormal test. When designing the first stress test section of a permeable structure, the following method shall be followed: For the cross-section of a permeable structure that is scaled down vertically according to the abnormal overall physical model, its vertical dimensions are retained while its horizontal dimensions are shortened. When the data points of the abnormal flume test deviate below the corresponding point group of the normal flume test, increase the horizontal dimension of the cross section of the abnormal test of the permeable structure. When the data points of the abnormal flume test deviate from the point group corresponding to the normal flume test, reduce the horizontal dimension of the cross section of the permeable structure in the abnormal test; Step 7: Conduct a flow-through abnormal water tank test on the cross-section of the permeable structure; Step 8: Calculate the local head loss and downstream velocity head of the permeable structure for each test group of the abnormal flume test, plot the data points of local head loss and downstream velocity head of the permeable structure corresponding to the abnormal flume test, and overlay them on the relationship graph of local head loss and downstream velocity head of the permeable structure obtained from the normal flume test in step 4. Step 9: Analyze the degree of agreement between the data points from the abnormal flume test in Step 8 and the relationship between the local head loss of the permeable structure and the downstream velocity head obtained from the normal flume test in Step 4, and make iterative adjustments until the agreement requirement is met. The iterative adjustment process is as follows: If the data point corresponding to the abnormal flume test is in the same group of data points as the normal flume test, then the permeable structure test section in step 6 will be used in the abnormal overall physical model. If the data points corresponding to the abnormal flume test deviate from the point group corresponding to the normal flume test, then modify the test section of the permeable structure and repeat steps 7 to 9 until the data points corresponding to the abnormal flume test and the relationship between the local head loss of the permeable structure and the downstream velocity head obtained from the normal flume test in step 4 meet the preset matching requirements. Step 10: Use the permeable structure cross-section obtained after adjustment in Step 9 as the permeable structure cross-section in the overall physical model of the abnormal structure.

2. The method for setting up permeable structures in the abnormal overall tidal sediment physical model according to claim 1, characterized in that, In step 1, the normal geometric scales corresponding to the normal flume test of the permeable structure cross-section have n possible values, denoted as: ,in ,and , For the vertical scale of the abnormal overall physical model test; By conducting water-flue tests on permeable structure sections under multiple different normal scale conditions, the geometric scale was ensured. Under these conditions, the scale effect will not affect the experimental results.

3. The method for setting up permeable structures in the abnormal overall tidal current sediment physical model according to claim 1, characterized in that, In step 3, normal flume tests are conducted on the cross-sections of permeable structures under various normal geometric scales. The specific steps are as follows: Step 3.1: For each test under a normal geometric scale, according to the cross-sectional dimensions of the permeable structure corresponding to that geometric scale, use the test structure corresponding to that geometric scale to build a permeable structure in the water tank. The axial direction of the permeable structure is consistent with the width direction of the water tank, the normal direction of the cross-section of the permeable structure is perpendicular to the water tank, and the permeable structure occupies the entire width of the water tank. Step 3.2: By changing the upstream water depth and flow velocity, conduct m measurements of the normal flume test of the permeable structure cross-section. The measurements include the water depth and average flow velocity in the upstream stable section and the downstream stable section of the permeable structure. Step 3.3: Repeat steps 3.1 to 3.2 to complete the normal flume test for all permeable structure cross sections with different geometric scales.

4. The method for setting up permeable structures in the abnormal overall tidal current sediment physical model according to claim 1, characterized in that, In steps 4 and 8: Downstream velocity head Calculate, where, The average flow velocity in the stable section downstream of the building. It is the acceleration due to gravity; Local head loss of permeable structures according to Calculate, where, and These refer to the water depths in the upstream and downstream stable sections of the permeable structure, respectively. The average flow velocity in the stable section upstream of the permeable structure. and These are the upstream and downstream flow velocity kinetic energy correction coefficients, respectively.

5. The method for setting up permeable structures in the abnormal overall tidal current sediment physical model according to claim 1, characterized in that, In step 7, a flow-through abnormal water tank test is conducted on the cross-section of the permeable structure. The specific steps are as follows: Step 7.1: Based on the abnormal test section of the permeable structure in Step 6, use the test structure corresponding to the vertical scale of the abnormal overall physical model to construct the permeable structure in the water tank. The normal direction of the permeable structure section is perpendicular to the water tank, and the permeable structure occupies the entire width of the water tank. Step 7.2: By changing the upstream water depth and flow velocity, conduct k measurements of the permeable structure cross-section through a variable flow flume test. The measurements include the water depth and average flow velocity in the upstream stable section and the downstream stable section of the permeable structure.

6. The method for setting up permeable structures in the abnormal overall tidal current sediment physical model according to claim 1 or 5, characterized in that, In the test, if the permeable structure cannot remain stable in the water flow, auxiliary stabilization tools are used to fix the permeable structure.

7. The method for setting up permeable structures in the abnormal overall tidal current sediment physical model according to claim 1, characterized in that, In step 10, the length of the permeable structure in the horizontal direction in the abnormal overall physical model is determined according to the plane scale of the abnormal overall physical model.

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