Method for calculating wave flow force shielding coefficient of sea-crossing bridge group pile foundation

Abstract

The invention discloses a method for calculating a wave flow force shielding coefficient of a sea-crossing bridge pile group foundation, and belongs to the technical field of pile group foundation wave flow force research. The method comprises the following steps: making a bridge pier, a bearing platform and a pile group foundation in a scaling-down manner, simulating an application scene and installing in a test wave pool; irregular waves are generated in the test wave pool through a wave maker, and the wave height and period of the waves in the test model are simulated; the water depth, the wave height, the wave period, the pile diameter and the pile distance in the test wave pool and the wave flow force borne by the pile foundation are measured respectively; and a wave flow force shielding coefficient calculation formula is provided based on analysis of the on-way change rule of the pile foundation wave flow force shielding coefficient. Compared with a calculation method in the current specification, the calculation method provided by the invention provides convenience for single pile stress re-checking calculation in the pile group, the calculation precision is improved, the cost increase caused by too conservative engineering design calculation is avoided, and the engineering construction cost is effectively saved.

Description

Technical Field

[0001] This invention relates to the field of wave-current force research technology for pile foundations, and in particular to a method for calculating the wave-current force shielding coefficient of pile foundations for cross-sea bridges. Background Technology

[0002] In recent years, cross-sea bridges and offshore wind power have developed rapidly, and their foundations often adopt the pile cap-pile group type. In addition to the vertical loads transmitted by the superstructure such as the bridge deck, trains, and wind turbines, pile group foundations also bear horizontal wave loads, and wave loads are more detrimental to the structural safety. Therefore, the assessment of the horizontal wave and current forces on pile group structures is crucial.

[0003] Pile group structures often consist of multiple small-diameter single piles arranged in a crisscross pattern. Under wave action, the front row of piles inevitably creates a shielding effect on the rear row, meaning the stress on the rear piles is reduced compared to the front piles. Determining a reasonable shielding coefficient is crucial for assessing the stress on pile group structures. However, there is currently no readily available calculation method. For structural safety considerations, the shielding coefficient is typically set to 1.0. While this coefficient is convenient for engineering applications, its accuracy is not high, leading to overly conservative calculation results and higher project costs.

[0004] To address these issues, this invention proposes a method for calculating the wave current shielding coefficient of pile foundations for cross-sea bridges. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies, such as the conservative use of wave current shielding coefficients for pile foundations and the lack of systematic theoretical calculation methods, which leads to high engineering costs. This invention proposes a method for calculating the wave current shielding coefficient of pile foundations for cross-sea bridges. This method ensures both ease of application in engineering and a certain degree of accuracy, making the engineering cost more reasonable.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for calculating the wave-current shielding coefficient of pile foundations for cross-sea bridges includes the following:

[0008] The pile foundation installation, including the bridge piers, pile caps and pile foundations, was scaled down and installed in the experimental wave pool to simulate the application scenario.

[0009] Hydrological conditions were set, and irregular waves were generated in the experimental wave pool using a wave generator to simulate the wave height and period in the experimental model.

[0010] Data measurements were taken, including water depth, wave height, wave period, pile diameter, pile spacing, and wave force on the pile foundation in the test wave pool.

[0011] Based on the analysis of the variation law of the wave-current shielding coefficient along the pile foundation, a formula for calculating the wave-current shielding coefficient is proposed.

[0012] As a further preferred embodiment of the present invention, the pile foundation installation involves proportionally scaled-down bridge piers, pile caps, and the pile foundation itself, and is installed in a test wave pool to simulate an application scenario, as detailed below:

[0013] The experimental model was fabricated considering different pile diameters and pile spacings. The structures of the piers, pile caps and pile group foundations in the experimental model were all scaled down according to a certain geometric scale. The experimental model maintained geometric similarity with the prototype structure, and the experimental model structure was simulated using a rigid structure.

[0014] After the test model is made, it is installed in the test section in the test wave pool. During installation, the monopile structure for force measurement is disconnected from the ground and the abutment. The monopile structure is fixed by a bracket. The rear side of the water-facing side of the monopile structure is connected to one side of the force sensor, and the other side of the force sensor is fixedly connected to the bracket.

[0015] As a further preferred embodiment of the present invention, the hydrological conditions are set by generating irregular waves in the experimental wave pool using a wave generator, and simulating the wave height and period in the experimental model, including:

[0016] The wave height and period of the waves in the experimental model are determined according to the gravity similarity criterion. The wave elements converted according to the scale of the experimental model are input into the computer to generate wave-generating signals and control the wave generator to generate irregular waves to simulate the wave height and period of the waves in the experimental model. The error between the simulated value and the design value of the wave height and period is controlled within ±2%. The flow velocity in the experimental model is determined according to the gravity similarity criterion, and the error of the average flow velocity is controlled within ±5%.

[0017] As a further preferred embodiment of the present invention, data measurement is performed, including measuring the water depth, wave height, wave period, pile diameter, pile spacing, and wave current force on the pile foundation in the test wave pool, as follows:

[0018] The water depth in the test wave pool is measured by a water gauge set on the side wall of the test wave pool. When the water level reaches the target water gauge mark, the filling of water into the test wave pool is stopped.

[0019] During the experiment, the design water flow was first simulated in the test wave pool, and the water flow velocity was measured using a propeller velocity meter installed in the test wave pool. Then, based on the water flow, the given wave elements were simulated, and the wave elements, including wave height and wave period, were measured using a wave height meter installed in the test wave pool.

[0020] The pile diameter and pile spacing were measured using a measuring ruler;

[0021] The wave force on the pile foundation of a monopile structure is measured using a force sensor.

[0022] As a further preferred embodiment of the present invention, based on the analysis of the variation law of the wave-current shielding coefficient along the pile foundation, a calculation formula for the wave-current shielding coefficient is proposed, the process of which is as follows:

[0023] The wave current force on the pile foundation of a single pile structure was measured by experimental model test. The first row of pile foundations was not affected by shielding, and the wave current force shielding coefficient was 1.0. The wave current force on the pile foundations of the subsequent rows of pile foundations gradually decreased relative to the first row of pile foundations and tended to stabilize. That is, the wave current force shielding coefficient gradually decreased from the first row to the rear and tended to stabilize.

[0024] Based on the fact that the shielding coefficient of the wave-current force on the pile foundation varies along the friction line according to the exponential function, the following formula for calculating the wave-current force reduction coefficient of each row of pile foundations along the friction line, including undetermined coefficients, is proposed:

[0025] ;

[0026] In the formula, For the first The shielding coefficient of the pile foundation. For the natural constant An exponential function with base 0; This refers to the numbering of the pile foundations. The pile spacing is along the wave direction; The diameter of the pile foundation; and Let be the coefficients to be determined, where and related, For intermediate parameters;

[0027] ;

[0028] In the formula, The maximum horizontal velocity of the water particle; For wave period;

[0029] Based on the proposed formula for calculating the wave flow reduction coefficient of each row of piles along the bearing path, which includes undetermined coefficients, a corresponding set of results was obtained for each set of test conditions measured in the test model. , and Value, index Indicates the first Various working conditions;

[0030] Based on multiple groups Value, take The average value is used as the coefficient to be determined. The value of , The average value is 0.5. ;

[0031] Based on multiple groups and The value is determined by using the least squares method for the unknown coefficients. and By performing a fitting analysis on the relationship between them, we obtain:

[0032] ;

[0033] The formula for calculating the wave current shielding coefficient of each row of piles along the path is as follows:

[0034] ;

[0035] in,

[0036] ;

[0037] ;

[0038] ;

[0039] ;

[0040] ;

[0041] In the formula, The maximum horizontal velocity of the wave trajectory of water particles. For water flow velocity, For wave height, Because of water depth, λ is the wavelength.

[0042] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention simulates actual application scenarios by setting up experimental models and optimizes the calculation method, making the calculation method of this invention closer to engineering practice. Using the calculation formula provided by this method, the wave current shielding coefficient can be accurately and quickly solved according to the collected hydrological conditions of the pile foundation, which facilitates the verification calculation of the stress of a single pile in a pile group. Compared with the method in the current specifications, this method improves the calculation accuracy, avoids the increase in cost caused by overly conservative engineering design calculations, and effectively saves engineering construction costs. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the installation of the test model in the method for calculating the wave current shielding coefficient of a cross-sea bridge pile foundation proposed in this invention. Figure 2 This is a schematic diagram of the pile foundation layout in the method for calculating the wave current shielding coefficient of a cross-sea bridge pile foundation proposed in this invention. Figure 3The time-domain variation curve of wave current force in the pile foundation is shown in the calculation method of wave current force shielding coefficient for cross-sea bridge pile foundation proposed in this invention. Figure 4 This invention presents a method for calculating the wave current shielding coefficient of a cross-sea bridge pile foundation, which involves the variation of the pile foundation wave current shielding coefficient along the bearing and the fitting curve. Figure 5 This is a fitting diagram of undetermined coefficients in the calculation method of wave current shielding coefficient for pile foundation of cross-sea bridge proposed in this invention.

[0044] The labels in the diagram are: 1. Pier; 2. Abutment; 3. Pile foundation; 4. Support; 5. Force sensor. Detailed Implementation

[0045] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0046] This invention proposes a method for calculating the wave-current shielding coefficient of a pile foundation for a cross-sea bridge. The method mainly includes the following:

[0047] The pile foundation was installed in a scaled-down manner, with pier 1, pile cap 2 and pile foundation 3 fabricated and installed in the experimental wave pool to simulate the application scenario.

[0048] Hydrological conditions were set, and irregular waves were generated in the experimental wave pool using a wave generator to simulate the wave height and period in the experimental model.

[0049] Data measurements were taken, including water depth, wave height, wave period, pile diameter, pile spacing, and wave force on the pile foundation in the test wave pool.

[0050] Based on the analysis of the variation law of the wave-current shielding coefficient along the pile foundation, a formula for calculating the wave-current shielding coefficient is proposed.

[0051] The above content will be explained in detail as follows:

[0052] like Figure 1 As shown, for the installation of the pile group foundation, pier 1, pile cap 2, and pile foundation 3 are all fabricated to scale and installed in the test wave pool to simulate the application scenario. The details are as follows:

[0053] The test model was constructed considering different pile diameters and pile spacings. The structures of pier 1, abutment 2, and pile foundation 3 in the test model were all scaled down according to a certain geometric scale. The test model maintained geometric similarity with the prototype structure. All structures in the test model were simulated using rigid structures, and each structure could be made of plexiglass with a certain strength and rigidity.

[0054] After the test model is fabricated, it is installed in the test section within the wave pool. For the single-pile structure of the force-measuring pile foundation 3, the connection between the force-measuring single-pile structure and the ground and pile cap 2 is disconnected during installation, leaving a small gap (approximately 2mm). The single-pile structure is fixed by bracket 4, with the rear side of the water-facing side of the single-pile structure connected to one side of the force sensor 5, and the other side of the force sensor 5 fixedly connected to bracket 4. That is, the force-measuring single-pile structure is not subjected to any external force except for contact with the force sensor 5 under wave action. The force sensor 5 in this scheme can be a commercially available waterproof pressure measuring device, sufficient to meet the force measurement requirements of the wave pressure on the face of the single-pile structure. The sampling frequency of the force sensor 5 can be selected as 125Hz. It is worth noting that, except for the single-pile structure involved in force measurement which is set to a suspended state, other non-force-measuring single-pile structures must maintain normal connection with the ground and pile cap 2.

[0055] Hydrological conditions were set by generating irregular waves in the experimental wave pool using a wave generator, and simulating the wave height and period in the experimental model, including:

[0056] The test waves in the test wave pool are irregular waves, and the wave spectrum of the irregular waves can be the Jonswap spectrum; the water flow is a unidirectional steady flow, and the effect of wave and current in the same direction is considered.

[0057] In the experimental model, the wave height and period are determined according to the gravity similarity criterion (the gravity similarity criterion, also known as the Froude criterion, is the core criterion for achieving gravity similarity in fluid mechanics model experiments. Its essence is to ensure that the ratio of inertial force to gravity is equal between the prototype and the model. It is derived from the d'Alembert theorem that when the flow is dominated by gravity, the progressive conditions of geometric similarity, kinematic similarity, and dynamic similarity must be met. Among them, dynamic similarity requires that the Froude number be kept strictly equal. Since this criterion is a mature technical means, it will not be elaborated on in this implementation). The wave elements converted according to the scale of the experimental model are input into the computer to generate wave-generating signals and control the wave generator to generate irregular waves to simulate the wave height and period in the experimental model. It should be noted that, in order to ensure that the experiment is more in line with actual applications, the error between the simulated values ​​and the design values ​​of wave height and period is controlled within ±2%; the flow velocity in the experimental model is determined according to the gravity similarity criterion, and the error of the average flow velocity is controlled within ±5%.

[0058] Data measurements were taken, including water depth, wave height, wave period, pile diameter, pile spacing, and wave force on pile foundation 3 within the test wave pool, as follows:

[0059] The water depth in the test wave pool is measured by a water gauge set on the side wall of the test wave pool. When the water level reaches the target water gauge mark, water is stopped being added to the test wave pool; if the water level is higher than the target water gauge mark, water is pumped out of the test wave pool.

[0060] During the experiment, the design water flow was first simulated in the test wave pool, and the water flow velocity was measured using a propeller velocity meter installed in the test wave pool. Then, based on the water flow, the given wave elements were simulated, and the wave elements, including wave height and wave period, were measured using a wave height meter installed in the test wave pool.

[0061] In this embodiment, the pile diameter and pile spacing can be obtained by direct measurement using a measuring ruler.

[0062] The wave current force on the pile foundation 3 of the monopile structure is measured by the force sensor 5 installed on the monopile structure.

[0063] Based on the analysis of the variation law of the wave-current shielding coefficient along the bearing, a calculation formula for the wave-current shielding coefficient is proposed, and the process is as follows:

[0064] like Figure 2 As shown, for a pile group structure, it can be divided into several rows perpendicular to the wave propagation direction and several columns along the wave propagation direction. As the waves and currents propagate forward, the first row of piles 3 is the first to be impacted by the waves and currents, followed by the second, third, fourth, and so on. Due to the protection of the first row of piles 3, the wave force experienced by the second row of piles 3 is reduced compared to the first row. The shielding coefficient of the wave force experienced by the second row of piles 3 is defined as:

[0065] The shielding coefficient of the wave current force on the second row of pile foundation 3 = the force on the second row of single piles / the force on the first row of single piles

[0066] As the waves propagate forward, the stress on the third row of pile foundations 3 will further decrease. The shielding coefficient of the wave current force on the third row of pile foundations 3 is defined as:

[0067] The shielding coefficient of the wave current force on the third row of pile foundation 3 = the force on the third row of single piles / the force on the first row of single piles

[0068] Following this logic, the shielding coefficient of the wave current force on the nth row of pile foundations 3, protected by the preceding pile foundation 3, is defined as:

[0069] The shielding coefficient of the wave current force on the nth row of pile foundation 3 = the force on the nth row of single piles / the force on the 1st row of single piles.

[0070] To achieve accurate and rapid calculation of the wave current shielding coefficient for each row of pile foundations 3, the following design scheme was adopted: First, a physical model test of wave current force on typical bridge foundations was conducted. The test considered different working conditions such as water depth, wave height, wave period, and water flow velocity. The wave current force on the single pile structure of each row of pile foundations 3 (row 1, row 2, row 3 up to row n (the last row)) in the pile group was measured under each working condition. Second, based on the measurement results, the variation law of the shielding coefficient of each row of pile foundations 3 along the friction distance (along the direction of wave propagation) was analyzed, and a calculation formula for the friction current shielding coefficient containing undetermined coefficients was proposed. Finally, the least squares method was used to perform fitting analysis on the undetermined coefficients to obtain the final calculation formula for the friction current shielding coefficient.

[0071] like Figure 3 As shown, the time-domain variation curve of the wave-current force on the single pile structure was obtained from the experimental measurement. The maximum value was taken as the wave-current force value on the single pile structure for analysis. Therefore, using the wave-current force on pile 3 of the single pile structure obtained from the experimental model, and according to the definition of the wave-current force reduction coefficient on the pile foundation, the value of the wave-current force reduction coefficient on pile 3 was calculated, that is:

[0072] The shielding coefficient of the wave current force on the nth row of pile foundation 3 = the nth row of pile foundation 3 Force on single pile in row / Force on single pile in row 1.

[0073] According to the test results of the experimental model, the wave current shielding coefficient of the first row of pile foundation 3 is 1.0, which is not affected by shielding. The wave current force on the pile foundation 3 in the rear row gradually decreases and tends to stabilize relative to the first row of pile foundation 3. That is, the wave current shielding coefficient gradually decreases from the first row to the rear row and tends to stabilize. The wave current shielding coefficient on the first row of pile foundation 3 is 1.0.

[0074] The experimental and fitted values ​​of the shading coefficient obtained from the experimental data are shown in Table 1.

[0075] Table 1. Experimental and fitted values ​​of the shading coefficient.

[0076]

[0077] like Figure 4 As shown, the shielding coefficient of the wave-current force on pile foundation 3 is plotted along the friction length and fitted curve. The shielding coefficient of the wave-current force decreases successively along the friction length, exhibiting an exponential change. The change curve of the shielding coefficient of the wave-current force on pile foundation 3 along the friction length conforms to the characteristics of an exponential function. Therefore, the following formula for calculating the wave-current force reduction coefficient of each row of pile foundations along the friction length, including undetermined coefficients, is proposed:

[0078] ;

[0079] In the formula, For the first The shielding coefficient of the pile foundation. For the natural constant An exponential function with base 0; This refers to the numbering of the pile foundations. =1, 2, 3, 4, 5...; The pile spacing is along the wave direction; The diameter of the pile foundation; and Let be the coefficients to be determined, where and related, The intermediate parameter is an important parameter in the study of the interaction between waves and pile structures. In this embodiment, it is defined as follows:

[0080] ;

[0081] In the formula, The maximum horizontal velocity of the water particle; For wave period;

[0082] Based on the proposed formula for calculating the wave flow reduction coefficient of each row of piles along the bearing path, which includes undetermined coefficients, a corresponding set of parameters can be obtained for each set of test conditions (different water depths, wave heights, wave periods, flow velocities, pile diameters, and pile spacing) measured in the test model. , and Value, index Indicates the first Various working conditions.

[0083] Based on multiple groups Value, take The average value is used as the coefficient to be determined. The value of , The average value is 0.5, which gives us... .

[0084] Based on multiple groups and Value, such as Figure 5 As shown, the least squares method is used to determine the coefficients. and By performing a fitting analysis on the relationship between them, we obtain:

[0085] ;

[0086] The final formula for calculating the wave current shielding coefficient of each row of piles along the route is as follows:

[0087] ;

[0088] in,

[0089] ;

[0090] ;

[0091] ;

[0092] ;

[0093] ;

[0094] In the formula, The maximum horizontal velocity of the water particle's orbital motion. For water flow velocity, For wave height, water depth λ is the wavelength.

[0095] It should be noted here that... g is the acceleration due to gravity, taken as 9.81 m / s². 2 ;wavelength It can be obtained through iterative calculation. In this embodiment, the iterative solution process is as follows:

[0096] Before and after iteration The iteration terminates when the values ​​differ by less than ±5%. The iteration steps are as follows:

[0097] Step 1: Command , will get Substitute value , can be obtained value,

[0098] like Then the iteration terminates, and the value is taken. = ;

[0099] like If so, proceed to step 2 and continue iterating.

[0100] Step 2: Substitution , can be obtained value,

[0101] like Then the iteration terminates, and the value is taken. = ;

[0102] like If so, proceed to step 3 and continue iterating.

[0103] Until:

[0104] Then the iteration terminates, and the value is taken. = .

[0105] It should be noted that any parts not covered in this invention are the same as or can be implemented using existing technology. The above description is merely a preferred embodiment of this invention, but the scope of protection of this invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this invention, based on the technical solution and inventive concept of this invention, should be covered within the scope of protection of this invention.

Claims

1. A method for calculating the wave current shielding coefficient of a pile foundation for a cross-sea bridge, characterized in that, Includes the following: The bridge piers, abutments, and pile foundations were all fabricated to scale and installed in the experimental wave pool to simulate the application scenario. Irregular waves were generated in the experimental wave pool using a wave generator, and the wave height and period of the waves in the experimental model were simulated. The water depth, wave height, wave period, pile diameter, pile spacing, and wave force on the pile foundation were measured in the test wave pool. Based on the analysis of the variation law of the wave-current shielding coefficient along the pile foundation, a formula for calculating the wave-current shielding coefficient is proposed.

2. The method for calculating the wave current shielding coefficient of a cross-sea bridge pile foundation according to claim 1, characterized in that, The bridge piers, abutments, and pile foundations were all fabricated to scale and installed in a test wave pool to simulate the application scenario. Details are as follows: The experimental model was fabricated by scaling down the structure of the bridge piers, abutments, and pile foundations according to a certain geometric scale. The experimental model maintained geometric similarity with the prototype structure, and the experimental model structure was simulated using a rigid structure. After the test model is made, it is installed in the test section in the test wave pool. During installation, the monopile structure for force measurement is disconnected from the ground and the abutment. The monopile structure is fixed by a bracket. The rear side of the water-facing side of the monopile structure is connected to one side of the force sensor, and the other side of the force sensor is fixedly connected to the bracket.

3. The method for calculating the wave current shielding coefficient of a cross-sea bridge pile foundation according to claim 1, characterized in that, The process of generating irregular waves in a test wave pool using a wave generator, and simulating the wave height and period in the test model, includes: The wave height and period of the waves in the experimental model are determined according to the gravity similarity criterion. The wave elements converted according to the scale of the experimental model are input into the computer to generate wave-generating signals and control the wave generator to generate irregular waves to simulate the wave height and period of the waves in the experimental model. The error between the simulated value and the design value of the wave height and period is controlled within ±2%. The flow velocity in the experimental model is determined according to the gravity similarity criterion, and the error of the average flow velocity is controlled within ±5%.

4. The method for calculating the wave current shielding coefficient of a cross-sea bridge pile foundation according to claim 1, characterized in that, The measurements of water depth, wave height, wave period, pile diameter, pile spacing, and wave force on the pile foundation in the test wave pool are performed as follows: The water depth in the test wave pool is measured by a water gauge set on the side wall of the test wave pool. When the water level reaches the target water gauge mark, the filling of water into the test wave pool is stopped. During the experiment, the design water flow was first simulated in the test wave pool, and the water flow velocity was measured using a propeller velocity meter installed in the test wave pool. Then, based on the water flow, the given wave elements were simulated, and the wave elements, including wave height and wave period, were measured using a wave height meter installed in the test wave pool. The pile diameter and pile spacing were measured using a measuring ruler; The wave force on the pile foundation of a monopile structure is measured using a force sensor.

5. The method for calculating the wave current shielding coefficient of a cross-sea bridge pile foundation according to claim 1, characterized in that, Based on the analysis of the variation law of the wave-current shielding coefficient along the pile foundation, a calculation formula for the wave-current shielding coefficient is proposed, and the process is as follows: The wave current force on the pile foundation of a single pile structure was measured by experimental model test. The first row of pile foundations was not affected by shielding, and the wave current force shielding coefficient was 1.

0. The wave current force on the pile foundations of the subsequent rows of pile foundations gradually decreased relative to the first row of pile foundations and tended to stabilize. That is, the wave current force shielding coefficient gradually decreased from the first row to the rear and tended to stabilize. The shielding coefficient of the wave-current force on the pile foundation varies along the bearing curve according to the exponential function. Therefore, the following formula for calculating the wave-current force reduction coefficient of each row of pile foundations along the bearing curve, including undetermined coefficients, is proposed: ； In the formula, For the first The shielding coefficient of the pile foundation. For the natural constant An exponential function with base 0; This refers to the numbering of the pile foundations. The pile spacing is along the wave direction; The diameter of the pile foundation; and Let be the coefficients to be determined, where and related, For intermediate parameters; ； In the formula, The maximum horizontal velocity of a water particle on the water surface; For wave period; Based on the proposed formula for calculating the wave flow reduction coefficient of each row of piles along the bearing path, which includes undetermined coefficients, a corresponding set of results was obtained for each set of test conditions measured in the test model. , and Values; Based on multiple groups Value, take The average value is used as the coefficient to be determined. The value of , The average value is 0.

5. ; Based on multiple groups and The value is determined by using the least squares method for the unknown coefficients. and By performing a fitting analysis on the relationship between them, we obtain: ； The formula for calculating the wave current shielding coefficient of each row of piles along the path is as follows: ； in, ； ； ； ； ； In the formula, The maximum horizontal velocity of the wave trajectory of water particles. For water flow velocity, For wave height, Because of water depth, λ is the wavelength.

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