Method and system for determining riprap displacement

Abstract

The invention provides a riprap displacement determination method and system. The method comprises the steps that flow field parameters of a river reach under different incoming flow conditions are simulated and studied based on a three-dimensional water and sediment-bed surface erosion and deposition model; designing and executing a generalized water tank test on the basis of the flow field parameters to obtain movement tracks of the riprap material in different hydrodynamic environments; setting throwing parameters according to the movement track, constructing a riprap drift distance calculation model, and calibrating key coefficients in the riprap drift distance calculation model; and combining the calibrated riprap drift distance calculation model with the three-dimensional water and sand-bed surface erosion and deposition model, and calculating and obtaining the riprap displacement under a specified incoming flow condition and block stone characteristics. According to the method, the motion law of the riprap material in different hydrodynamic environments is researched, and theoretical support is provided for solving the problems of uneven settlement, insufficient construction precision and the like in the submerged spur dike construction process.

Description

Technical Field

[0001] This invention belongs to the field of hydrological and water conservancy engineering technology, and in particular relates to a method and system for determining the displacement distance of a rock dump. Background Technology

[0002] The Zhou Tianhe section of the Jingjiang River is an important navigable section in the middle reaches of the Yangtze River. Affected by factors such as the Three Gorges Project's scheduling and changes in sediment conditions, the riverbed has suffered severe scouring, threatening navigation safety and efficiency. Submerged groynes play a crucial role in regulating flow and stabilizing the riverbed during waterway improvement. However, the flow field structure near these groynes is complex, exhibiting phenomena such as shifts in the main dynamic axis, enhanced local backflow, and increased turbulence, leading to severe local scouring and decreased groyne stability. Studying the flow field characteristics and rockfall patterns in the submerged groyne area of ​​the Zhou Tianhe section of the Jingjiang River is of significant theoretical and engineering value for ensuring the effectiveness of waterway improvement projects and improving navigation capacity.

[0003] Current research on the hydrodynamic characteristics and rockfall motion patterns in submerged groynes is relatively weak. By establishing a three-dimensional hydrodynamic model, this study will delve into the flow field evolution characteristics under different flow conditions and their impact on riverbed scouring, providing a scientific basis for the design and optimization of submerged groynes. Simultaneously, through generalized flume experiments, the motion patterns of rockfall materials under different hydrodynamic environments will be investigated, providing theoretical support for addressing issues such as uneven settlement and insufficient construction precision during submerged groyne construction. The research findings can provide technical guidance for the Jingjiang River channel improvement project. Summary of the Invention

[0004] This invention uses a three-dimensional water-sediment-bed scouring and deposition model to simulate the flow field characteristics of a river section under different inflow conditions and output flow field parameters. Based on the flow field parameters obtained from the mathematical model, a generalized flume experiment is designed to obtain the motion trajectory of the rock-throwing material under different hydrodynamic environments. Based on the motion trajectory of different materials, throwing parameters are set to achieve precise throwing.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A method for determining the displacement distance of a boulder includes the following steps: The flow field parameters of the river section under different inflow conditions were simulated and studied based on the three-dimensional water-sediment-bed scouring and deposition model. Based on the flow field parameters, a generalized flume test was designed and executed to obtain the motion trajectory of the riprap material under different hydrodynamic environments. Based on the motion trajectory, set the throwing parameters, construct a stone-throwing distance calculation model, and calibrate the key coefficients in the stone-throwing distance calculation model; The calibrated rock-drop distance calculation model is combined with the three-dimensional water-sand-bed scouring and silting model to calculate and obtain the rock-drop distance under specified inflow conditions and rock characteristics.

[0006] Furthermore, the three-dimensional water-sediment-bed scouring and deposition model is constructed based on the finite volume method of unstructured meshes, and the flow field parameters at a given time are calculated by solving the non-constant three-dimensional water-sediment transport equations.

[0007] Furthermore, the calculation of the flow field parameters by solving the non-steady three-dimensional water and sediment transport equations specifically includes the following steps: Obtain the basic conditions and calculation parameters. An unstructured grid of the river channel was constructed based on measured river topographic data. Based on the aforementioned basic conditions and calculation parameters, the non-steady three-dimensional water and sediment transport equations are solved using the unstructured grid to obtain water and sediment elements at a given time. The non-steady three-dimensional water and sediment transport equations include at least the flow continuity equation, momentum equation, suspended sediment transport equation, and riverbed deformation equation.

[0008] Furthermore, the basic conditions include inlet flow rate, outlet water level, initial riverbed elevation, initial flow velocity and sediment concentration distribution, and boundary conditions. The calculation parameters include bed roughness height, sediment settling velocity for each particle size group, maximum thickness of the active layer of the riverbed, and Coriolis force coefficient.

[0009] Furthermore, the generalized flume test is designed based on the gravity similarity criterion, and uses an acoustic Doppler current meter to measure the water flow velocity. The motion trajectory and drift distance of the thrown stone are recorded by combining high-speed photography with a coordinate grid.

[0010] Furthermore, the calculation model for the boulder drift distance is as follows:

[0011] in, S The distance of the stone-throwing drift. H Because of the water depth, u m The maximum vertical flow velocity, The uniform settling velocity of the boulders. n The velocity distribution index, α For comprehensive motion parameters.

[0012] Furthermore, the comprehensive motion parameters in the stone-throwing distance calculation model α With uniform settling speed of the boulders Calculated using the following formula:

[0013]

[0014] in, η x The horizontal drag coefficient, ηy The vertical drag coefficient is... β For the additional quality coefficient, ρ The density of water, ρ s The density of the stone, D The particle size of the stone is... g It is the acceleration due to gravity. Pi is the mathematical constant of a circle.

[0015] Furthermore, the key coefficients in the calibrated boulder drift distance calculation model include: the horizontal drag coefficient. η x Vertical drag coefficient η y Additional quality coefficient β .

[0016] Furthermore, the calibration process is as follows: Using the least squares method, by adjusting η x , η y and β The value of the key coefficient is used to fit the drift distance to the experimental drift distance, and the sum of squared deviations between the two is minimized to determine the optimal value of the key coefficient. Collect measured data from the construction site, including stone particle size, water depth, surface velocity, and actual drift distance; use the measured data to adjust the coefficients. η x , η y and β Recalibrate and update.

[0017] On the other hand, the present invention provides a system for determining the displacement distance of a boulder, comprising: Parameter extraction module: It is used to simulate and study the flow field parameters of a river section under different inflow conditions based on a three-dimensional water-sediment-bed scour and deposition model; Experimental analysis module: It is used to design and execute generalized flume tests based on the flow field parameters to obtain the motion trajectory of the riprap material under different hydrodynamic environments; Model building and calibration module: It is used to set the throwing parameters according to the motion trajectory, build a stone throwing distance calculation model, and calibrate the key coefficients in the stone throwing distance calculation model; The calculation output module is used to combine the calibrated rock-drop distance calculation model with the three-dimensional water-sand-bed scouring and silting model to calculate and obtain the rock-drop distance under specified inflow conditions and rock characteristics.

[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) It achieves an improvement from experience-based judgment to scientific prediction: This invention abandons the traditional approach of relying on rough empirical formulas. By establishing a three-dimensional water and sediment model and combining it with a generalized flume test, it starts from the mechanism of water and sediment movement, so that the determination process of the displacement distance of the riprap is based on a solid scientific theory, which significantly improves the scientificity and reliability of the method. (2) It significantly improves the prediction accuracy and engineering reliability: The numerical model and drift distance calculation formula are calibrated and verified through physical model tests, forming a closed loop of "simulation guiding the test and test correcting the model", which ensures that the final prediction result is closer to the actual engineering situation, thereby improving the construction accuracy and long-term stability of the submerged spur dam from the source. (3) It effectively solves the core problems of uneven settlement and inaccurate positioning: Traditional methods cannot accurately predict the underwater movement trajectory of the riprap, resulting in the loss of control over the dam body shape. This invention can accurately calculate the drift distance of the riprap in a specific water flow, guide the construction party to throw it at a suitable position upstream, and make the riprap land accurately, fundamentally solving the problems of uneven settlement and construction deviation. (4) It has strong pertinence and adaptability: The core model of this method can be calibrated and constructed according to the hydrological and sediment conditions of specific river sections, realizing personalized design of "one policy for one river" or even "one policy for one dam", overcoming the shortcomings of the poor applicability of general empirical formulas in different rivers and different working conditions. (5) It brings significant comprehensive economic benefits: By accurately simulating and optimizing the construction plan in advance, it can effectively reduce trial and error and repetition in construction, save engineering materials and construction period, and significantly reduce the maintenance and reinforcement costs in the later stage due to the improvement of engineering quality, thus realizing the comprehensive benefits of cost reduction and efficiency improvement. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a flowchart illustrating an embodiment of the present invention; Figure 2 This is a schematic diagram of a local river channel computation grid according to an embodiment of the present invention; Figure 3 This is a schematic diagram showing the relationship between the drift distance and the mass of the thrown stone when the water depth is 10m and the surface flow velocity is 1m / s, according to an embodiment of the present invention. Figure 4 This is a schematic diagram illustrating the relationship between drift distance and stone mass when the water depth is 10m and the surface flow velocity is 2m / s, according to an embodiment of the present invention. Figure 5 A schematic diagram of the surface flow field calculated by a three-dimensional water-sediment mathematical model. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In specific implementation, the method proposed in the technical solution of this invention can be automatically executed by those skilled in the art using computer software technology. System devices for implementing the method, such as computer-readable storage media storing the corresponding computer program of the technical solution of this invention and computer equipment including the computer program running the corresponding computer program, should also be within the protection scope of this invention.

[0023] Example 1 like Figure 1 The present invention illustrates a method for determining the displacement distance of a stone-throwing object, comprising the following steps: Step S1: Simulate and study the flow field parameters of the river section under different inflow conditions based on the three-dimensional water-sediment-bed scouring and deposition model; Step S2: Based on the flow field parameters, design and execute a generalized flume test to obtain the motion trajectory of the riprap material under different hydrodynamic environments; Step S3: Set the throwing parameters according to the motion trajectory, construct the stone throwing distance calculation model, and calibrate the key coefficients in the stone throwing distance calculation model; Step S4: Combine the calibrated rock-drop distance calculation model with the three-dimensional water-sand-bed scouring and silting model to calculate and obtain the rock-drop distance under specified inflow conditions and rock characteristics.

[0024] This invention aims to provide a precise and reliable method for determining the displacement of thrown stones. Its core lies in combining the macroscopic simulation capability of a three-dimensional water and sediment mathematical model with the microscopic mechanism research of a generalized flume experiment, and through a rigorous parameter calibration and optimization process, it ultimately achieves accurate prediction of the displacement of thrown stones in the field.

[0025] In one embodiment, the three-dimensional water-sediment-bed scouring and deposition model is constructed based on the finite volume method of unstructured meshes, and the flow field parameters at a given time are calculated by solving the non-constant three-dimensional water-sediment transport equations.

[0026] The flow field parameters are calculated by solving the non-steady three-dimensional water and sediment transport equations in step S1, specifically including the following steps: Obtain the basic conditions and calculation parameters. An unstructured grid of the river channel was constructed based on measured river topographic data. Based on the aforementioned basic conditions and calculation parameters, the non-steady three-dimensional water and sediment transport equations are solved using the unstructured grid to obtain water and sediment elements at a given time. The non-steady three-dimensional water and sediment transport equations include at least the flow continuity equation, momentum equation, suspended sediment transport equation, and riverbed deformation equation.

[0027] The basic conditions are: inlet flow rate, outlet water level, riverbank soil layer data, physical and mechanical properties of each soil layer, initial conditions (including initial riverbed elevation, flow velocity and sediment concentration distribution), boundary conditions, calculation time period (0~T), calculation time step (dt), and the assigned time t=0. The calculation parameters include bed roughness height, sediment settling velocity for each particle size group, maximum thickness of the active layer, Coriolis force coefficient, and vertical eddy viscosity coefficient. Initial conditions are given for the entire calculation area, including initial values ​​for water level, riverbed elevation, flow velocity, sediment concentration, and bed sediment gradation. Boundary conditions include upstream given flow rate, suspended sediment concentration, water temperature, and downstream given water level. In this embodiment, the unstructured grid of the river channel is as follows: Figure 2 As shown, the specific implementation is as follows: Based on the measured scatter plot data of the river channel topography, the river channel boundary is drawn, an unstructured grid of the river channel is generated, and topographic data is interpolated at the grid nodes to obtain the generalized grid node numbers (1, 2, 3…N) and elevation information. , , ,…., ), the grid cell number and the information of the constituent nodes; Based on the computational conditions and parameters, and using an unstructured grid of the river channel, the following set of unsteady three-dimensional water and sediment transport equations are solved using the finite volume method to obtain the equations for a given time period. t The time-varying parameters include water level and stratified flow velocity ( , , , ..., ), Flow stratification sediment concentration ( , , , ..., ), bed surface elevation ( , , , ..., The water and sediment elements: among which, , , , ..., They represent the first t The layered flow velocities at the 1st, 2nd, 3rd...Nth grid nodes at time points. , , , ..., They represent the first t Sediment content of flow stratification at grid nodes 1, 2, 3....N at time points; , , , ..., They represent the first t The bed elevation of the 1st, 2nd, 3rd...Nth grid nodes at time 1; The non-steady three-dimensional equation set of water and sediment transport equations includes at least the flow continuity equation, momentum equation, suspended sediment transport equation, and riverbed deformation equation, among which... The continuity equation, momentum equation, and pressure equation for water flow are as follows: Equation (1) Equation (2) Equation (3) Equation (4) Equation (5) In the formula, x , y , z These are the coordinates for east, north, and the vertical direction in a rectangular coordinate system, respectively. u , v , w They are speeds at x , y , z Component of direction (m / s) t Time (s); ρ The density of water (kg / m3); p Total pressure (Pa); The pressure at the water surface is in Pa. Hydrostatic pressure (Pa); f The Coriolis force coefficient; g The acceleration due to gravity (m / s²); Km is the vertical eddy viscosity coefficient (m2 / s). Fu , Fv , Fw These are the momentum diffusion terms (m / s²) in the u, v, and w directions, respectively. For reference density (kg / m3).

[0028] The vertical mixing of the model adopts the Mellor-Yamada 2.5th order turbulent closed model modified by Galperin et al. (1988), and the horizontal mixing is determined by the horizontal diffusion coefficient (Shi Shenyang et al., 2020), which is suitable for simulating water and sediment dynamics in marine and tidal river sections. In the boundary layer, the turbulent kinetic energy (q2 This is caused by the vertical shear of the water flow near the boundary. q2 and q2l It can be represented as: Equation (6) Equation (7) In the formula, This represents turbulent kinetic energy (m² / s²). Indicates the turbulent characteristic length (m); It is the vertical diffusion coefficient of turbulent kinetic energy (m2 / s). =1.80; and The horizontal diffusion term (m2 / s3) of the turbulent kinetic energy and turbulent characteristic length is solved using the Smagorinsky formula (Smagorinsky, 1963); , These are the shear force generation term and the buoyancy generation term of the turbulent kinetic energy, respectively. For reference density (kg / m3). , where is the turbulent kinetic energy dissipation rate (m2 / s3), and the parameter is... B 1 = 0.74; Let be the wall approximation function, where , The height of the free surface (m). The water depth (m) is relative to the reference surface. Kármán's constant =1.33, Kh It is the coefficient of thermal vertical eddy friction.

[0029] In the formula, and The turbulence equation can be closed using the following formula: Equation (8) Equation (9) In the formula, As a stable function, it is defined as: Equation (10) In the formula, These are intermediate parameters.

[0030] The three-dimensional suspended sediment transport equation is expressed as: Equation (11) In the formula, the subscript i Indicates the first i Group of sediments; Indicates the first iConcentration of suspended sediment (kg / m3). The horizontal diffusion coefficient of sediment (m² / s) is set in the model as the same as the horizontal eddy viscosity of the water flow. equal, denoted as the vertical diffusion coefficient of suspended sediment (m² / s). For the first i Settling velocity of suspended sediment (m / s).

[0031] No. i Settling velocity of suspended sediment The following calculation was performed using Zhang Ruijin's formula: Equation (12) In the formula, The kinematic viscosity of water (m² / s) is related to water temperature. The dry density of the sediment. For the first i The average particle size of the sediment.

[0032] The equation for riverbed deformation caused by suspended sediment transport can be expressed as: Equation (13) In the formula, It is the dry density of the bed sand (kg / m3). It is the riverbed elevation (m). t The time is expressed in seconds. and It is the settling flux (kg / (m2.s)) and uplift flux (kg / (m2.s)) of the i-th group of sediment at the bottom interface.

[0033] Calculated by the following formula: Equation (14) Equation (15) In the formula, The probability of sediment deposition; The concentration (kg / m3) of the i-th group of sediment in the near-bottom suspended sediment. This represents the shear stress (N / m2) exerted by the water flow on the bottom of the riverbed. For the first i Critical sedimentation stress (N / m2) for sediment. The erosion coefficient of sediment (kg / (m2.s)) The porosity of the upper layer of the riverbed. For the first i The initial shear stress (N / m2) of the sediment. For the first i The settling velocity of the sediment.

[0034] The shear stress formula considering the influence of turbulent kinetic energy is used to calculate the stress in the study area. The calculated results agree well with the measured results.

[0035] In the formula, The shear stress (N / m2) exerted by the water flow on the bottom of the riverbed. E The turbulent kinetic energy at the bottom of the riverbed is (m2 / s2). The density of water (kg / m3); C is a coefficient, with a value of 0.19.

[0036] Shear stress on the bottom of the riverbed by water flow Calculate using the following formula: Equation (16) Equation (17) Equation (18) In the formula, and They are respectively x and y Shear stress at the bottom of the riverbed in the direction of (N / m2). Cd The drag coefficient is calculated using the following formula: ,in Zab and Zo These represent the thickness (m) of the bottom water layer and the roughness height (m) of the riverbed, respectively. This is the minimum drag coefficient, typically taken as 0.0075 in shallow water and 0.0025 in deep water.

[0037] No. i Initiation shear stress of sediment Calculate using the following formula: Equation (19) In the formula, , These are the natural bulk density of sediment and the bulk density of water (N / m3), respectively. For the first i The average particle size (m) of the sediment is given by c, which is a constant and has a value of 2.9 × 10⁻⁴ N / m.

[0038] The distribution of flow velocity magnitudes in the calculated flow field parameters in this embodiment is as follows: Figure 5 As shown. In one embodiment, step S2: Designing and executing a generalized flume test based on the flow field parameters to obtain the motion trajectory of the riprap material under different hydrodynamic environments, specifically including: A self-circulating water supply system was used, with a water level gauge on one side of the tank. An ADV acoustic Doppler current meter was used to measure the water flow velocity. To facilitate reading the drift distance and trajectory of the stones, a 1 cm × 1 cm grid was drawn on the bottom and sides of the tank. A high-speed camera was mounted on the side of the tank to capture the stone trajectory. The experimental model was designed using the gravity similarity criterion.

[0039] In one embodiment, step S3: setting throwing parameters according to the motion trajectory, constructing a stone-throwing distance calculation model, and calibrating the key coefficients in the stone-throwing distance calculation model; specifically including: Most existing research indicates that the vertical velocity distribution of water flow in open channels mainly follows an exponential distribution, and its velocity distribution formula is: Equation (20) In the formula: y This refers to the vertical height from the baseboard. um The maximum vertical flow velocity; H For water depth; n It is an index.

[0040] A stone that falls into moving water, y The directional stone sinks under the influence of gravity, while simultaneously experiencing upward buoyancy and water flow resistance. y The dynamic equilibrium equations in the direction are: Equation (21) In the formula: G is gravity; P is buoyancy; f Let D be the water flow resistance; M be the mass of the boulder; and ω be the settling velocity of the boulder. Let the boulder diameter be D, the boulder density be ρs, the water density be ρ, the vertical drag coefficient be ηy, and the gravitational acceleration be g. Then, gravity: Equation (22) buoyancy: Equation (23) resistance: Equation (24) Substituting equations (22)-(24) into equation 21, we get: Equation (25) Regardless of the distance the rock is above the water surface h Whether a rock falls freely into water or sinks from the surface with zero initial velocity, its sinking speed will change over time. t It quickly approaches a constant speed. Let From Equation 25, the uniform settling velocity is: Equation (26) In addition, the boulders in the water flow x The direction is carried and pushed by the water flow, causing a horizontal displacement along the direction of the water flow. For any given moment... t The effective pushing force acting on the stone F It can be written as: Equation (27) In the formula: u The water flow velocity; v For the stone in x Horizontal displacement velocity in the direction; η x is the horizontal drag coefficient. Considering the rock undergoing variable acceleration motion under the thrust of the water flow, the dynamic equilibrium equation of the rock in the x-direction of the moving water is: Equation (28) In the formula: The inertial force generated by variable acceleration motion; Ma The additional mass caused by variable acceleration motion is: Equation (29) In the formula: β is the additional mass coefficient. Substituting equation (29) into equation (28), we get Equation (30) make: Equation (31) Integrating equation (30), from the initial conditions t =0, u = um , v =0 yields: Equation (32) Will Substituting equation (20) into equation (32), and considering vertical displacement... ,have to: Equation (33) Vertical integration of equation (33), and from the initial conditions t =0 x =0 yields: Equation (34) make The drift distance S of the stone is: Equation (35) In the formula: α and α are determined by equations (7) and (12) respectively; where the stone particle size D can be taken as the isochoric particle size, determined by the following formula: Equation (36) By generalizing the values ​​of the calibration coefficients ηx, ηy, and β from the flume test, the least squares method is used to fit the test results, so that the calculated drift distance of the i-th stone determined by formula (36) is ( Si The sum of squares of the deviations between the test value of the i-th stone and the drift distance (si) is minimized.

[0041] Equation (37) The number of stones; i For the stone number; Si The first one determined by equation (35) i Calculated drift distance of each stone; si δmin is the experimental value of the drift distance of the j-th stone; δmin is the minimum sum of squares of deviation.

[0042] Step S4: Combine the calibrated rock-drop distance calculation model with the three-dimensional water-sand-bed scouring and silting model to calculate and obtain the rock-drop distance under specified inflow conditions and rock characteristics.

[0043] Taking a certain submerged groyne section as an example, the specific process is as follows: The design was based on the gravity similarity criterion. Considering various factors, a model length scale of 30 was chosen, resulting in a mass scale and force scale of 27,000, and a flow velocity scale and settling velocity scale of 5.477. Tests were conducted at surface flow velocities of um = 1.0, 1.5, and 2.0 m / s. Based on the engineering design water level and the bottom elevation of the engineering area, a water depth of H = 10 m was chosen for the tests. The test was carried out, and the distance of the thrown stones was recorded under different water depths and flow conditions. Figure 3 , Figure 4 ).

[0044] The values ​​of the calibration coefficients ηx, ηy and β are fitted to the experimental results using the least squares method, so that the calculated drift distance of the i-th stone determined by formula (36) is ( Si The sum of squares of the deviations from the experimental drift distance (si) of the i-th stone and the i-th stone is minimized. Figure 3 and Figure 4 The values ​​were determined to be ηx = 4.5, ηy = 0.52 and β = 0.22.

[0045] Based on the three-dimensional hydro-sediment mathematical model, the surface velocity and water depth at the Z6 submerged spur in the Zhou Tian River section were calculated. The results are shown in the table below.

[0046]

[0047] Based on the calibrated formula parameters and the flow parameters calculated in step 4, the rock-dropping distance under different inflow conditions was calculated. The results are shown in the table below.

[0048]

[0049] The on-site riprap construction provides technical reference. In addition, the construction site measures and collects actual data including "riprap particle size D", water depth H (m), surface flow velocity (m / s) and riprap drift distance (m).

[0050] Stone displacement distance and stone particle size table

[0051] Based on the field measurement data and generalized flume test in step 5, the coefficient η is recalibrated using the least squares method. x η y And the value of β.

[0052] The table in step 4 is updated based on the recalibrated values ​​of ηx (8.2), ηy (05), and β (075). This makes the calculation results in the table more closely reflect the actual working conditions.

[0053]

[0054] This embodiment obtains the motion trajectory of the rock-throwing material under different hydrodynamic environments. Based on the motion trajectory of different materials, the throwing parameters are set to achieve precise throwing.

[0055] Example 2 This embodiment provides a stone-throwing distance determination system according to the present invention, comprising: Parameter extraction module: It is used to simulate and study the flow field parameters of a river section under different inflow conditions based on a three-dimensional water-sediment-bed scour and deposition model; Experimental analysis module: It is used to design and execute generalized flume tests based on the flow field parameters to obtain the motion trajectory of the riprap material under different hydrodynamic environments; Model building and calibration module: It is used to set the throwing parameters according to the motion trajectory, build a stone throwing distance calculation model, and calibrate the key coefficients in the stone throwing distance calculation model; The calculation output module is used to combine the calibrated rock-drop distance calculation model with the three-dimensional water-sand-bed scouring and silting model to calculate and obtain the rock-drop distance under specified inflow conditions and rock characteristics.

[0056] It should be understood that any parts not described in detail in this specification belong to the prior art.

[0057] It should be understood that the above description of the preferred embodiments is quite detailed, but this should not be construed as limiting the scope of protection of this invention. It is neither necessary nor possible to exhaustively describe all possible implementations. Those skilled in the art, guided by this invention, can make substitutions or modifications without departing from the scope of the claims, all of which fall within the scope of protection of this invention. The scope of protection of this invention should be determined by the appended claims.

Claims

1. A method for determining the displacement distance of a boulder, characterized in that, Includes the following steps: The flow field parameters of the river section under different inflow conditions were simulated and studied based on the three-dimensional water-sediment-bed scouring and deposition model. Based on the flow field parameters, a generalized flume test was designed and executed to obtain the motion trajectory of the riprap material under different hydrodynamic environments. Based on the motion trajectory, set the throwing parameters, construct a stone-throwing distance calculation model, and calibrate the key coefficients in the stone-throwing distance calculation model; The calibrated rock-drop distance calculation model is combined with the three-dimensional water-sand-bed scouring and silting model to calculate and obtain the rock-drop distance under specified inflow conditions and rock characteristics.

2. The method for determining the displacement distance of a boulder according to claim 1, characterized in that, The three-dimensional water-sediment-bed scouring and deposition model is constructed based on the finite volume method of unstructured meshes, and the flow field parameters at a given time are calculated by solving the non-constant three-dimensional water-sediment transport equations.

3. The method for determining the displacement distance of a boulder according to claim 2, characterized in that, The calculation of the flow field parameters by solving the non-steady three-dimensional water and sediment transport equations specifically includes the following steps: Obtain the basic conditions and calculation parameters. An unstructured grid of the river channel was constructed based on measured river topographic data. Based on the aforementioned basic conditions and calculation parameters, the non-steady three-dimensional water and sediment transport equations are solved using the unstructured grid to obtain water and sediment elements at a given time. The non-steady three-dimensional water and sediment transport equations include at least the flow continuity equation, momentum equation, suspended sediment transport equation, and riverbed deformation equation.

4. The method for determining the displacement distance of a boulder according to claim 3, characterized in that, The basic conditions include inlet flow rate, outlet water level, initial riverbed elevation, initial flow velocity and sediment concentration distribution, and boundary conditions. The calculation parameters include bed roughness height, sediment settling velocity for each particle size group, maximum thickness of the active layer of the riverbed, and Coriolis force coefficient.

5. The method for determining the displacement distance of a stone-throwing object according to claim 1, characterized in that, The generalized flume experiment was designed based on the gravity similarity criterion and used an acoustic Doppler current meter to measure the water flow velocity. The motion trajectory and drift distance of the thrown stone were recorded by combining high-speed photography with a coordinate grid.

6. The method for determining the displacement distance of a boulder according to claim 1, characterized in that, The model for calculating the distance of the boulder throw is as follows: in, S The distance of the stone-throwing drift. H Because of the water depth, u m The maximum vertical flow velocity, The uniform settling velocity of the boulders. n The velocity distribution index, α For comprehensive motion parameters.

7. The method for determining the displacement distance of a boulder according to claim 6, characterized in that, The comprehensive motion parameters in the stone-throwing distance calculation model α With uniform settling speed of the boulders Calculated using the following formula: in, η x The horizontal drag coefficient, η y The vertical drag coefficient is... β For the additional quality coefficient, ρ The density of water, ρs The density of the stone, D The particle size of the stone is... g It is the acceleration due to gravity. Pi is the mathematical constant of a circle.

8. The method for determining the displacement distance of a boulder according to claim 1, characterized in that, The key coefficients in calibrating the boulder drift distance calculation model include: horizontal drag coefficient. η x Vertical drag coefficient η y Additional quality coefficient β .

9. The method for determining the displacement distance of a boulder according to claim 1, characterized in that, The calibration process is as follows: Using the least squares method, by adjusting η x , η y and β The value of the key coefficient is used to fit the drift distance to the experimental drift distance, and the sum of squared deviations between the two is minimized to determine the optimal value of the key coefficient. Collect measured data from the construction site, including stone particle size, water depth, surface velocity, and actual drift distance; use the measured data to adjust the coefficients. η x , η y and β Recalibrate and update.

10. A system for determining the displacement distance of a boulder, characterized in that, include: Parameter extraction module: It is used to simulate and study the flow field parameters of a river section under different inflow conditions based on a three-dimensional water-sediment-bed scour and deposition model; Experimental analysis module: It is used to design and execute generalized flume tests based on the flow field parameters to obtain the motion trajectory of the riprap material under different hydrodynamic environments; Model building and calibration module: It is used to set the throwing parameters according to the motion trajectory, build a stone throwing distance calculation model, and calibrate the key coefficients in the stone throwing distance calculation model; The calculation output module is used to combine the calibrated stone displacement calculation model with the three-dimensional water-sand-bed scouring and silting model to calculate and obtain the stone displacement distance under specified inflow conditions and stone characteristics. The stone-throwing distance determination system is used to perform the steps in the stone-throwing distance determination method according to any one of claims 1-9.

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