River channel scouring coarsening parameter determination method, device and equipment and storage medium

Abstract

The invention relates to the technical field of hydraulics and river dynamics, and discloses a river channel scouring coarsening parameter determination method, device and equipment and a storage medium, in the calculation process, the target water flow condition is determined by adjusting the initial parameter, and the dynamic change of the water flow condition in the actual scouring process can be reflected. Furthermore, relevant parameters under different particle sizes can be accurately estimated through a dichotomy and a linear interpolation method, so that relatively accurate initial accumulative gradation is obtained. Furthermore, a bed sand gradation coarsening calculation method in the preset bed load scouring process is utilized to adjust the initial accumulative gradation, and the influence of the bed load on the bed sand gradation in the scouring process is considered, so that the calculation result is more in line with the bed sand change condition in the actual scouring process. Finally, the target river channel scouring coarsening parameter set is determined by comparing the target accumulative gradation with the preset threshold value, the accuracy of river channel scouring coarsening calculation is remarkably improved, and errors in actual engineering are reduced.

Description

Technical Field

[0001] The present invention relates to the technical fields of hydraulics and river dynamics, and particularly relates to a method, device, equipment and storage medium for determining river channel scour coarsening parameters. Background Art

[0002] At present, the phenomenon of river channel scour coarsening has been widely studied in many pebble riverbeds and pebble-sand mixed riverbeds. Especially when clear water is discharged in the river channel, the formation of the bed sediment coarsening layer has an important influence on the scour process. However, there are still problems with large errors in the existing calculation methods for estimating the thickness of the coarsening layer, the grading of the stable coarsening layer, and the ultimate scour depth. Summary of the Invention

[0003] In view of this, the present invention provides a method, device, equipment and storage medium for determining river channel scour coarsening parameters, so as to solve the problem that there are still large errors in the existing calculation methods for estimating the thickness of the coarsening layer, the grading of the stable coarsening layer, and the ultimate scour depth.

[0004] In a first aspect, the present invention provides a method for determining river channel scour coarsening parameters, the method comprising:

[0005] Obtaining an initial river channel scour parameter set and an initial scour step length under initial water flow conditions; based on the initial river channel scour parameter set and the initial scour step length, determining target water flow conditions after being processed by a preset adjustment method; based on a preset incipient motion velocity relational expression and the initial river channel scour parameter set, calculating a critical non-scouring particle size and an initial cumulative grading under the target water flow conditions by using the bisection method and the linear interpolation method; calculating a characteristic particle size of the riverbed bed sediment under the target water flow conditions and adjusting the initial cumulative grading by using a calculation method for coarsening of the bed sediment grading during the transport of bed load, to obtain a target cumulative grading; when the target cumulative grading is less than or equal to a preset threshold, determining a target river channel scour coarsening parameter set based on the target water flow conditions.

[0006] The method for determining the river channel scouring coarsening parameters provided by the present invention can reflect the dynamic changes of the water flow conditions during the actual scouring process by using a preset adjustment method to process the initial parameters during the calculation process. This dynamic adjustment is more in line with the actual situation of river channel scouring and helps to improve the accuracy of the finally determined scouring coarsening parameters. Further, the relevant parameters under different particle sizes can be accurately estimated by the bisection method and the linear interpolation method, so as to obtain a relatively accurate initial cumulative gradation. Further, by using the calculation method for coarsening the bed sediment gradation during the preset bed load scouring process, the characteristic particle size of the riverbed bed sediment is calculated, and the initial cumulative gradation is adjusted to obtain the target cumulative gradation, considering the influence of the bed load on the bed sediment gradation during the scouring process, making the calculation result more in line with the bed sediment change situation during the actual scouring process. Finally, the target river channel scouring coarsening parameter set is determined by comparing the target cumulative gradation with the preset threshold, ensuring that the finally obtained parameter set is determined under a reasonable scouring stable state and can accurately reflect the scouring coarsening characteristics of the river channel under specific conditions. Therefore, by implementing the present invention, the accuracy of river channel scouring coarsening calculation is significantly improved, and the error in actual engineering is reduced.

[0007] In an alternative embodiment, based on the initial river channel scouring parameter set and the initial scouring step length, after being processed by a preset adjustment method, the target water flow conditions are determined, including:

[0008] Calculating the scouring percentage based on the initial river channel scouring parameter set and the initial scouring step length; respectively adjusting the river depth and river velocity in the initial river channel scouring parameter set to obtain the actual water depth and the actual water velocity; determining the target water flow conditions based on the scouring percentage, the actual water depth, and the actual water velocity.

[0009] The method for determining the river channel scouring coarsening parameters provided by the present invention can more realistically reflect the dynamic changes of the water flow conditions during the scouring process by calculating the scouring percentage and adjusting the water depth and the water velocity, and further can make the determined target water flow conditions have important significance for subsequent calculations such as the critical non-scouring particle size and the cumulative gradation of the river channel scouring coarsening parameters.

[0010] In an alternative embodiment, based on the preset incipient motion velocity relationship formula and the initial river channel scouring parameter set, the critical non-scouring particle size and the initial cumulative gradation under the target water flow conditions are calculated by using the bisection method and the linear interpolation method, including:

[0011] Obtaining the preset incipient motion velocity relationship formula; determining the calculation method for the coarsening gradation of the erosion-resistant layer based on the target water flow conditions; calculating the critical non-scouring particle size under the target water flow conditions by using the bisection method and the linear interpolation method based on the preset incipient motion velocity relationship formula and the initial river channel scouring parameter set; calculating the initial cumulative gradation under the target water flow conditions by using the calculation method for the coarsening gradation of the erosion-resistant layer based on the critical non-scouring particle size.

[0012] The method for determining the river channel scouring coarsening parameters provided by the present invention can accurately estimate the relevant parameters at different particle sizes through the bisection method and the linear interpolation method, so as to obtain a relatively accurate initial cumulative gradation, providing support for the subsequent calculation of the river channel scouring coarsening parameters.

[0013] In an alternative embodiment, obtaining the preset incipient flow velocity relationship includes:

[0014] Obtaining the incipient motion criterion of the riverbed sediment; based on the incipient motion criterion of the riverbed sediment, determining the incipient flow velocity relationship at the bottom of the riverbed; based on the incipient flow velocity relationship at the bottom of the riverbed and the correlation of scouring parameters, determining the preset incipient flow velocity relationship.

[0015] In an alternative embodiment, the method further includes: when the target cumulative gradation is greater than the preset threshold, modifying the initial scouring step length and re-determining the target flow conditions, and iterating repeatedly until the target cumulative gradation is greater than the preset threshold and the target river channel scouring coarsening parameter set is obtained.

[0016] The method for determining the river channel scouring coarsening parameters provided by the present invention can improve the accuracy of the river channel scouring coarsening calculation by modifying the initial scouring step length and re-determining the target flow conditions and iterating repeatedly when the target cumulative gradation is greater than the preset threshold.

[0017] In an alternative embodiment, the calculation method for the coarsening gradation of the erosion-resistant layer includes the pebble coarsening gradation method and the pebble-sand mixture coarsening gradation method.

[0018] In a second aspect, the present invention provides a device for determining river channel scouring coarsening parameters, and the device includes:

[0019] An acquisition module, configured to acquire an initial river channel scouring parameter set and an initial scouring step length under initial flow conditions; a first determination module, configured to determine target flow conditions based on the initial river channel scouring parameter set and the initial scouring step length through processing by a preset adjustment method; a calculation module, configured to calculate the critical non-scouring particle size and the initial cumulative gradation under the target flow conditions based on the preset incipient flow velocity relationship and the initial river channel scouring parameter set by using the bisection method and the linear interpolation method; an adjustment module, configured to calculate the characteristic particle size of the riverbed bed material under the target flow conditions and adjust the initial cumulative gradation by using the preset calculation method for the coarsening of the bed material gradation during the transport of bed load to obtain the target cumulative gradation; a second determination module, configured to determine the target river channel scouring coarsening parameter set based on the target flow conditions when the target cumulative gradation is less than or equal to the preset threshold.

[0020] In a third aspect, the present invention provides a computer device, comprising: a memory and a processor, which are communicatively connected to each other. The memory stores computer instructions, and the processor executes the computer instructions to perform the method for determining river channel scouring and coarsening parameters according to the first aspect or any corresponding embodiment thereof.

[0021] In a fourth aspect, the present invention provides a computer-readable storage medium, on which computer instructions are stored. The computer instructions are used to cause a computer to perform the method for determining river channel scouring and coarsening parameters according to the first aspect or any corresponding embodiment thereof.

[0022] In a fifth aspect, the present invention provides a computer program product, comprising computer instructions, which are used to cause a computer to perform the method for determining river channel scouring and coarsening parameters according to the first aspect or any corresponding embodiment thereof. Description of the Drawings

[0023] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0024] Figure 1 is a schematic flowchart of a method for determining river channel scouring and coarsening parameters according to an embodiment of the present invention;

[0025] Figure 2 is a schematic flowchart of another method for determining river channel scouring and coarsening parameters according to an embodiment of the present invention;

[0026] Figure 3 is a schematic flowchart of a method for calculating river channel scouring and coarsening based on the Han Qiwei method according to an embodiment of the present invention;

[0027] Figure 4 is a block diagram of the structure of a device for determining river channel scouring and coarsening parameters according to an embodiment of the present invention;

[0028] Figure 5 is a schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. Detailed Embodiments

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts fall within the protection scope of the present invention.

[0030] According to an embodiment of the present invention, an embodiment of a method for determining river channel scour coarsening parameters is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. And although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0031] In this embodiment, a method for determining river channel scour coarsening parameters is provided, which can be used in electronic devices such as computers, mobile phones, and tablet computers. Figure 1 It is a flowchart of the method for determining river channel scour coarsening parameters according to an embodiment of the present invention, as Figure 1 shown, and this process includes the following steps:

[0032] Step S101, obtain an initial river channel scour parameter set and an initial scour step length under initial water flow conditions.

[0033] Specifically, the initial river channel scour parameter set may include unit-width discharge Q, water depth H0, average flow velocity V0, particle size D l , grading P 1l0 , maximum particle size D M , etc.

[0034] Furthermore, the initial scour step length is n*Δh. Wherein, n represents the number of loop calculations. Here, n = 1, that is, the initial scour step length is n*Δh = Δh.

[0035] Step S102, based on the initial river channel scour parameter set and the initial scour step length, through the processing of a preset adjustment method, determine the target water flow conditions.

[0036] Specifically, the relevant scour parameters (such as water depth, flow velocity, etc.) in the initial river channel scour parameter set can be adjusted through a preset adjustment method to re-determine the new changed target water flow conditions.

[0037] Step S103, based on the preset incipient motion velocity relationship formula and the initial river channel scour parameter set, use the bisection method and the linear interpolation method to calculate the critical non-scouring particle size and the initial cumulative grading under the target water flow conditions.

[0038] Among them, the bisection method is an iterative algorithm for numerical calculation. Its basic idea is to divide an interval into two parts, and then determine which part the root is located in according to the function values at the endpoints of the interval, and then continue to perform the next round of interval division and judgment in that part until a certain accuracy requirement is met; the linear interpolation method represents a numerical approximation method based on a linear relationship, which is used to estimate the function value at a certain point between two known points given their function values.

[0039] Specifically, based on the preset starting flow velocity relationship formula and the initial river channel scour parameter set, the critical non-scouring particle size and the initial cumulative gradation under the target water flow conditions can be calculated by combining the bisection method and the linear interpolation method.

[0040] Step S104: Using the calculation method for the coarsening of the bed sediment gradation during the preset bed load scour process, calculate the characteristic particle size of the riverbed bed sediment under the target water flow conditions and adjust the initial cumulative gradation to obtain the target cumulative gradation.

[0041] Specifically, the coarse particle gradation in the erosion-resistant coarsening layer is associated with the limit scour depth. It is generally considered that when sediment particles are scoured under the condition of clear water flowing downstream until the limit scour depth is reached and the sediment particles can no longer be entrained, the formed coarsening layer is the erosion-resistant layer, and its thickness is generally represented by the maximum particle size D in the coarsening particle gradation. M It is expressed as.

[0042] Furthermore, based on the research results of Academician Han Qiwei, the calculation formulas for the coarsening of the bed sediment gradation during the bed load scour process are shown in the following relationships (1) and (2):

[0043]

[0044] In the formula: p 1l0 represents the gradation of the l-th group of particle sizes at the initial time; D m represents the characteristic particle size of the riverbed bed sediment; v represents the sorting coefficient during scour; D l represents the minimum coarsening particle size; λ * represents the scour percentage; p 1l represents the gradation of the l-th group of particle sizes after scour, that is, the percentage of the weight occupied by the l-th group of sediment.

[0045] Furthermore, by combining the above relationships (1) and (2), the characteristic particle size D of the riverbed bed sediment under the target water flow conditions can be calculated, and then the initial cumulative gradation p m can be adjusted to obtain the target cumulative gradation. 1l0

[0046] Step S105: When the target cumulative gradation is less than or equal to the preset threshold, determine the target river channel scour coarsening parameter set based on the target water flow conditions.

[0047] Among them, the target river channel scouring coarsening parameter set may include the scouring depth n*Δh, flow velocity under the target water flow conditions, the scouring percentage, as well as the corresponding particle size and gradation.

[0048] Specifically, if the target cumulative gradation under the new target water flow conditions is less than or equal to the preset threshold (1%), the scouring stops at this time, and the river channel scouring parameters under the target water flow conditions at this time are used as the scouring coarsening parameter set of the target river channel after scouring.

[0049] The method for determining the river channel scouring coarsening parameters provided in this embodiment can reflect the dynamic changes of water flow conditions during the actual scouring process by using a preset adjustment method to process the initial parameters during the calculation process. This dynamic adjustment is more in line with the actual situation of river channel scouring and helps to improve the accuracy of the finally determined scouring coarsening parameters. Further, the relevant parameters at different particle sizes can be accurately estimated through the bisection method and the linear interpolation method, so as to obtain a relatively accurate initial cumulative gradation. Further, by using the calculation method for coarsening the bed sediment gradation during the preset bed load scouring process, the characteristic particle size of the riverbed bed sediment is calculated, and the initial cumulative gradation is adjusted to obtain the target cumulative gradation, taking into account the influence of the bed load on the bed sediment gradation during the scouring process, making the calculation result more in line with the bed sediment change situation during the actual scouring process. Finally, by comparing the target cumulative gradation with the preset threshold, the target river channel scouring coarsening parameter set is determined, ensuring that the finally obtained parameter set is determined under a reasonable scouring stable state and can accurately reflect the scouring coarsening characteristics of the river channel under specific conditions. Therefore, by implementing the present invention, the accuracy of river channel scouring coarsening calculation is significantly improved, and the error in actual engineering is reduced.

[0050] In this embodiment, a method for determining river channel scouring coarsening parameters is provided, which can be used in electronic devices such as computers, mobile phones, tablet computers, etc. Figure 2 is a flowchart of the method for determining river channel scouring coarsening parameters according to an embodiment of the present invention, as Figure 2 shown, and this process includes the following steps:

[0051] Step S201, obtain the initial river channel scouring parameter set and the initial scouring step length under the initial water flow conditions. For details, please refer to Figure 1 step S101 of the embodiment shown, which will not be elaborated here.

[0052] Step S202, based on the initial river channel scouring parameter set and the initial scouring step length, determine the target water flow conditions after being processed by a preset adjustment method.

[0053] Specifically, the above step S202 includes:

[0054] Step S2021, calculate the scour percentage based on the initial river channel scour parameter set and the initial scour step length.

[0055] Specifically, the scour percentage refers to the ratio of the sediment washed away to the sediment participating in the scour within a certain time period, denoted by λ * which represents the degree of scour. For pebble riverbeds or pebble-sand mixed riverbeds, its calculation formula is shown as the following relation (3):

[0056]

[0057] In the formula: h represents the scour depth; h0 represents the thickness of the stable roughened layer, generally represented by the maximum particle size D in the coarse particle gradation M representative.

[0058] Step S2022, adjust the river channel water depth and river channel flow velocity in the initial river channel scour parameter set respectively to obtain the actual water depth and actual flow velocity.

[0059] Specifically, adjust the river channel water depth H0 to obtain the actual water depth H, as shown in the following relation (4):

[0060] H = Δh + H0 (4)

[0061] Furthermore, adjust the river channel flow velocity to obtain the actual flow velocity V, as shown in the following relation (5):

[0062]

[0063] Step S2023, determine the target flow conditions based on the scour percentage, actual water depth and actual flow velocity.

[0064] Specifically, the new target flow conditions can be determined according to the obtained scour percentage λ * , actual water depth H and actual flow velocity V.

[0065] Step S203, based on the preset incipient flow velocity relation and the initial river channel scour parameter set, use the bisection method and linear interpolation method to calculate the critical non-scouring particle size and the initial cumulative gradation under the target flow conditions.

[0066] Specifically, the above step S203 includes:

[0067] Step S2031, obtain the preset incipient flow velocity relation.

[0068] In some alternative embodiments, the above step S2031 includes:

[0069] Step a1, obtain the incipient motion criterion of the riverbed sediment.

[0070] Step a2: Determine the relationship of incipient velocity at the riverbed bottom based on the incipient criterion of riverbed sediment.

[0071] Step a3: Determine the preset incipient velocity relationship based on the relationship of incipient velocity at the riverbed bottom and the correlation of scour parameters.

[0072] Specifically, the incipient motion of sediment refers to a process under certain conditions. Given an incipient criterion, there is an incipient velocity. Therefore, the incipient velocity actually has a certain conventional nature. According to the incipient criterion, the incipient velocity of cobbles given is calculated by the theoretical formula for the incipient motion of non-uniform particles, and its relative sediment transport rate is shown in the following relationship (6):

[0073]

[0074] In the formula: q bl represents the unit sediment transport rate of bed load; γ s represents the unit weight of cobble particles (generally taken as 2650 kg / m 3 ); D l represents the particle size of the l-th group of sediment in non-uniform sediment; represents the average particle size of non-uniform sediment; m0 represents the static compaction coefficient (which can be taken as 0.4); ε 1l represents the incipient probability, which is and function; U 2l represents the rolling velocity of the l-th group of cobbles, and is also and function; ω l represents the characteristic velocity of particles when sediment incipiently moves; V bl represents the incipient bottom velocity; λ qbl represents the dimensionless sediment transport rate at the incipient motion of this particle size group.

[0075] Furthermore, for a cobble riverbed or a cobble-braided riverbed, its dimensionless sediment transport rate uses the dimensionless sediment transport rate of non-uniform sediment as the incipient criterion, that is, the incipient velocity expressed by the bottom velocity is shown in the following relationships (7) and (8):

[0076]

[0077] In the formula: C x represents the particle frontal thrust coefficient, and its value is 0.4; γ represents the unit weight of water; g represents the acceleration of gravity.

[0078] Furthermore, the calculations of the above relationships (6) and (7) are quite complex. λ qbl , ε 1l , etc. have been calculated according to the theoretical formula. Based on this, when λ qbl = 0.3×10 -3When The relationship with l is shown in Table 1 below. Therefore, as long as D in the non-uniform bed material is known l , V can be obtained by looking up from looking up to obtain V bl .

[0079] Table 1, Relationship table

[0080]

[0081] Furthermore, when converting the incipient flow velocity expressed in terms of the bottom velocity to the average velocity, the following relationships (9) and (10) are adopted:

[0082]

[0083]

[0084] Furthermore, considering the situation under the limit equilibrium state, at this time the particle size range of the pebble particles is narrow, and the difference between the minimum coarsening particle size D l and the average particle size is small, generally about 0.5 - 0.9. For safety considerations, we temporarily take 0.61. Then At this time, the above relationship (9) can be converted into the following relationship (11):

[0085]

[0086] Furthermore, the above relationship (11) is the preset incipient flow velocity relationship.

[0087] Step S2032, determine the calculation method of the coarsening gradation of the erosion-resistant layer based on the target water flow conditions.

[0088] Specifically, different target water flow conditions correspond to different calculation methods of the coarsening gradation of the erosion-resistant layer, which may include:

[0089] (1) Calculation of the coarsening gradation of pebbles

[0090] Specifically, the basis for the coarsening calculation is the above relationship (6). Furthermore, according to the theoretical results, the above relationship (6) can be simplified into the following relationship (12) for pebble bed load:

[0091]

[0092] In the formula: p bl represents the bed load gradation; q represents the unit-width discharge; J represents the energy slope, which can generally be replaced by the water surface slope; C represents the coefficient.

[0093] Further, summing up the above relation (12) gives the following relation (13):

[0094]

[0095] Further, based on the above relations (12) and (13), the relation between the bed load gradation and the bed material gradation can be obtained, as shown in the following relation (14):

[0096]

[0097] Further, substituting the above relation (14) into the bed material gradation change equation gives the following relation (15):

[0098]

[0099] In the formula: W represents the weight of the bed material participating in scouring and sorting.

[0100] Further, rewriting the above relation (15) gives the following relation (16):

[0101]

[0102] Further, the determination of the scouring percentage is shown in the following relation (17):

[0103]

[0104] Further, in actual calculation, it can be first assumed that Calculate p 1l , so as to calculate a set of functional relations, as shown in the following relation (18):

[0105] p 1l (l = 1, 2, 3,....., n) ~ λ * ~ Δh (18)

[0106] Further, the obtained p 1l is the coarsening gradation after the scour depth Δh.

[0107] (2) Calculation of the coarsening gradation of pebble sandwiched with sand

[0108] Specifically, the coarsening gradation calculated in the above (1) is completely composed of the pebble particle size gradation. In the actual scour coarsening process, there are finer particle sizes sheltered by the coarse particles filled below the minimum coarsening particle size. For a pebble riverbed, its erosion-resistant layer is only one layer thick of the coarsest particles to form a surface coarsening layer. For the following layers, the compaction coefficient of this surface coarsening layer is small (generally 0.4), and the fine particle part affected by the sheltering effect is only filled in the lower part of this coarsening layer, where D0 is the minimum coarsening particle size in the coarsening layer, D Mis the maximum particle size in the roughened layer, and D0 is the minimum roughened particle size in the roughened layer, which is also the maximum particle size in the filling particles. The filling percentage D < D0 refers to the particle weight percentage P[D < D0]. If the static compaction coefficient of the coarse particles is taken as 0.4, then the weight of the coarse particles in the anti-scour roughened layer per unit area is shown in the following relationship (19):

[0109] G c = 0.4D m r s (19)

[0110] Furthermore, in the filling layer, the volume of the coarse particles per unit area is 0.4D0, and the volume of the fine particles filled is 0.6D0. In general, the sediment in these volumes should continue to the suspended sediment particle size. During the research on the dry unit weight, Academician Han Qiwei conducted in-depth research on the filling of fine particles in the pores of coarse particles and concluded that fine particles can be filled only when they are less than an order of magnitude. Therefore, for pebble riverbeds or pebble-bed rivers with sand, if the maximum particle size of the pebble particles is greater than 300 mm, then there are two groups of particle sizes for filling, which are 30 mm > D1 > 10 mm and 10 mm > D2 > 1 mm. If the maximum particle size of the pebble particles is below 150 mm, the two groups of filling particle sizes are and at this time, and the dry unit weights of the two groups of filling particles are 20 mm > D1 > 5 mm and 5 mm > D2 > 0.5 mm. Therefore, the weight G1 of the first group of sediment particles representing the particle size in the filler is shown in the following relationship (20):

[0111]

[0112] Furthermore, because the particles are first filled within a thickness of 0.6D0, and its dry unit weight is r s ′1, so the particle weight per unit area is 0.6D0r s ′1. Secondly, the thickness of the part filled with pebbles is 0.4D0, and the corresponding porosity is Therefore, there is still 0.4 filler in the voids of the coarse particles where r s ′ M represents the dry unit weight of the coarse particles. Therefore, the second group of fillers D2 only fills the pores of the first group of particles, and its volume is while is the porosity of the particle size group of

[0113] Furthermore, the weight G2 of the second filling group is shown in the following relationship (21):

[0114]

[0115] Among them, are the pores remaining after the first group of filling. Therefore, the percentage of the particles filled in the first group is shown by the following relational expression (22):

[0116]

[0117] Further, substituting the above various quantities into the relational expression (22) and simplifying, the following relational expression (23) is obtained:

[0118]

[0119] Further, the percentage of the particles filled in the second group is shown by the following relational expression (24):

[0120]

[0121] Further, substituting the above various quantities into the relational expression (24) and simplifying, the following relational expression (25) is obtained:

[0122]

[0123] Among them, D2 in the above relational expression (25) represents the minimum particle size in the filling material.

[0124] Further, the percentage of all the filled particles is shown by the following relational expression (26):

[0125]

[0126] Further, the dry unit weight in the above various expressions is determined by the following relational expression (27):

[0127]

[0128] In the formula: D is in mm, and the parameter particle size D c = 1 mm, and the dry unit weight is in t / m 3 calculated.

[0129] Further, the cumulative gradation of the bed sediment of the coarsening layer after filling is determined according to the following relational expression (28):

[0130]

[0131] In the formula: P1′ .l represents the coarse particle gradation without considering the filling material, that is, the value directly calculated by the coarsening formula.

[0132] Step S2033: Based on the preset starting flow velocity relational expression and the initial river channel scouring parameter set, use the bisection method and the linear interpolation method to calculate the critical non-scouring particle size under the target water flow conditions.

[0133] Specifically, the calculation of river channel scour and coarsening involves the scour depth. When calculating the average cross-section velocity, the water depth should be the scoured velocity, as shown in the following relational expression (29):

[0134]

[0135] In the formula: V represents the average cross-section velocity after scour; A0 represents the initial cross-sectional area of flow; B represents the water surface width of the cross-section; Q is the cross-sectional flow rate.

[0136] And when the average cross-section velocity is equal to the incipient motion velocity of the particles (V = V c,l ), the incipient diameter D l under the adjusted flow conditions can be obtained by combining the bisection method and the linear interpolation method after scour Δh.

[0137] Furthermore, assume that after scour Δh, the critical non-scouring diameter of the river channel is D0, and let D0 = D l .

[0138] Step S2034: Based on the critical non-scouring diameter, calculate the initial cumulative gradation under the target flow conditions by using the calculation method of the anti-scouring layer coarsening gradation.

[0139] Specifically, according to the obtained critical non-scouring diameter, the initial cumulative gradation under the current flow conditions can be calculated by using the calculation method of the anti-scouring layer coarsening gradation determined in the above step S2032.

[0140] Step S204: Use the preset calculation method for the coarsening of the bed sediment gradation during the bed load scour to calculate the characteristic diameter of the river bed sediment under the target flow conditions and adjust the initial cumulative gradation to obtain the target cumulative gradation. For details, please refer to Figure 1 Step S104 of the illustrated embodiment, which will not be elaborated here.

[0141] Step S205: When the target cumulative gradation is less than or equal to the preset threshold, determine the target river channel scour and coarsening parameter set based on the target flow conditions. For details, please refer to Figure 1 Step S105 of the illustrated embodiment, which will not be elaborated here.

[0142] Step S206: When the target cumulative gradation is greater than the preset threshold, modify the initial scour step length and re-determine the target flow conditions, and iterate repeatedly until the target cumulative gradation is greater than the preset threshold and the target river channel scour and coarsening parameter set is obtained.

[0143] Specifically, if the target cumulative gradation is greater than the preset threshold (1%), after modifying the initial scour step length and re-determining the target flow conditions, repeat steps S203 to S206 until the target cumulative gradation is greater than the preset threshold and the target river channel scour and coarsening parameter set is obtained.

[0144] The method for determining the river channel scouring coarsening parameters provided in this embodiment can more realistically reflect the dynamic changes of water flow conditions during the scouring process by calculating the scouring percentage and adjusting the water depth and flow velocity. Furthermore, it can make the determined target water flow conditions have important significance for subsequent calculations of river channel scouring coarsening parameters such as the critical non-scouring particle size and cumulative gradation. Further, through the bisection method and linear interpolation method, relevant parameters at different particle sizes can be accurately estimated, thereby obtaining a relatively accurate initial cumulative gradation. Further, by using the calculation method for bed sediment gradation coarsening during the preset bed load scouring process, the characteristic particle size of the riverbed bed sediment is calculated, and the initial cumulative gradation is adjusted to obtain the target cumulative gradation, considering the influence of bed load on the bed sediment gradation during the scouring process, making the calculation results more consistent with the actual changes in bed sediment during the scouring process. Finally, by comparing the target cumulative gradation with the preset threshold, the target river channel scouring coarsening parameter set is determined, ensuring that the finally obtained parameter set is determined under a reasonable scouring stable state and can accurately reflect the scouring coarsening characteristics of the river channel under specific conditions. Therefore, by implementing the present invention, the accuracy of river channel scouring coarsening calculation is significantly improved, and the error in actual engineering is reduced.

[0145] So far, there have been many studies on the scouring coarsening of pebble riverbeds or pebble-sand mixed riverbeds, and the understanding of them is basically the same. The ultimate equilibrium state of their scouring coarsening is the formation of a stable erosion-resistant coarsening layer. At this time, very little sediment can be entrained from the bed surface, and the interaction process between water flow and sediment can be considered as the critical entrainment condition of non-uniform sediment. Research and design are carried out on the calculation methods of the coarsening layer thickness, the gradation of the stable coarsening layer, and the ultimate scouring depth during the scouring coarsening process of pebble riverbeds or pebble-sand mixed riverbeds.

[0146] In one example, a method for calculating river channel scouring coarsening based on the method of Han Qiwei is provided. This method can accurately calculate the coarsening layer thickness and ultimate scouring depth of the river channel during the process of clear water discharge from the reservoir, predict the bed sediment gradation when the riverbed scours to a stable state, and finally obtain the ultimate scouring depth of each cross-section of the river channel. By calculating the critical entrainment condition of non-uniform sediment, the coarsening layer thickness, and the scouring percentage of bed load, an operable analysis process and formula calculation method are provided. Compared with existing research, this example can better reflect the actual river channel scouring coarsening process. Specifically, it includes:

[0147] (1.1) Scouring coarsening flow chart

[0148] The research results of scouring and coarsening by Academician Han Qiwei comprehensively consider conditions such as the flow rate, water depth, and bed sediment gradation on the riverbed surface during scouring. According to the characteristics of particle sorting during the riverbed scouring and coarsening process, the coarsening layer can accommodate the coarsest particle size, and taking the maximum particle size value in the bed sediment as the thickness of the stable erosion-resistant layer is more inclusive. During the scouring and coarsening process, a dynamic change adjustment mechanism between the scouring flow and bed sediment coarsening is established, and the hydraulic conditions and bed sediment changes are quantitatively processed until the scouring ability of the water flow is equal to the erosion-resistant ability of the riverbed bed sediment, forming a stable erosion-resistant coarsening layer, and the scouring and coarsening finally stop.

[0149] The ultimate scouring depth refers to the cumulative scouring thickness when the upstream incoming water of the river reach is clear water, or under a given flow condition, for a riverbed with a certain bed sediment gradation, after continuous scouring and coarsening for a long time, until it can no longer be scoured. Due to the constantly changing actual hydraulic conditions and the randomness of sediment particle movement, there are significant differences in the bed sediment gradation at various locations on the bed surface, and there is no critical condition for a riverbed that can no longer be scoured. Therefore, the ultimate scouring depth is relative. It is also possible to define the ultimate scouring depth with the upstream incoming water not being clear water but having a certain sediment concentration condition, but the incoming water condition with a certain sediment concentration discharged is difficult to control and difficult to achieve. At this time, the concept of the ultimate scouring depth is even more difficult to clarify. The ultimate scouring depth referred to in this patent is defined under the condition of discharging clear water. The ultimate scouring depth and the critical non-scouring particle size need to be calculated by trial and error. The entire process of scouring and coarsening calculation is as Figure 3 shown.

[0150] (1.2) Thickness of the erosion-resistant coarsening layer of pebble riverbed or pebble-sand mixed riverbed

[0151] After the reservoir is built, during the process of discharging clear water for scouring, the movement intensity of pebbles is very weak. Under general hydraulic conditions, they will not form pebble waves, and it is also unlikely to have large-scale scouring locally. Therefore, a certain particle size value of a certain particle can be selected as the thickness of the coarsening layer based on the coarse particles. Considering the particle sorting during the riverbed coarsening process, the coarsening layer can accommodate the coarsest particle size. Therefore, the thickness of the coarsening layer should be the maximum particle size D M . On the other hand, considering that the maximum particle size value of the coarsening layer is often unstable in the bed sediment gradation, the D 90 or D 95 of the coarse particle gradation in the coarsening layer can also be taken as the thickness of the coarsening layer. There is some exchange coarsening during the scour of bed load in the river channel, the coarse particle gradation in the coarsening layer will change, and the thickness of the coarsening layer is not fixed. Selecting D M as the thickness of the coarsening layer during the scouring stage is more inclusive. However, if it is noted that there will also be some exchange coarsening in the scour of bed load to some extent, using D M is more inclusive.

[0152] (1.3) Scouring percentage

[0153] The scouring percentage refers to the ratio of the scoured sediment to the sediment participating in scouring within a certain time period, denoted by, which represents the degree of scouring. For pebble riverbeds or pebble-sand mixed riverbeds, its calculation formula is as shown in the above relation (3).

[0154] (1.4) Calculation of the incipient velocity of bed material: As shown in the above step S2031.

[0155] (1.5) Coarse particle gradation in the erosion-resistant layer

[0156] Associated with the ultimate scouring depth is the coarse particle gradation in the erosion-resistant roughened layer. Generally, it is considered that when sediment particles are scoured under the condition of clear water discharge until the ultimate scouring depth is reached and the sediment particles can no longer be incipiently moved, the formed roughened layer is the erosion-resistant layer, and its thickness is generally represented by the maximum particle size D in the coarse particle gradation M .

[0157] Furthermore, based on the research results of Academician Han Qiwei, the calculation formulas for the coarsening of bed sediment gradation during the scouring process of bed load are as shown in the above relations (1) and (2).

[0158] (1.5.1) Pebble coarsening gradation: As shown in the content of pebble coarsening gradation calculation in the above step S2032.

[0159] (1.5.2) Pebble-sand mixed coarsening gradation: As shown in the content of pebble-sand mixed coarsening gradation calculation in the above step S2032.

[0160] (1.6) Calculation of the ultimate scouring depth

[0161] The calculation of river channel scouring and coarsening involves the scouring depth. When calculating the average cross-sectional velocity, the water depth should be the scoured velocity as shown in the above relation (29).

[0162] And from the equality of the average cross-sectional velocity and the incipient velocity of particles (V = V c,l ), the incipient particle size D under the adjusted water flow conditions after scouring by Δh can be obtained l .

[0163] Furthermore, let the critical non-scouring particle size of the river channel after scouring by Δh be D0, and set D0 = D l .

[0164] Furthermore, calculate the gradation of each particle size in the river channel under the adjusted water flow conditions after scouring by Δh. When the cumulative gradation of the critical supplementary particle size is not greater than 1%, the scouring stops, that is, P(D < D0) ≤ 1%.

[0165] Furthermore, when calculating the ultimate scouring depth, trial calculation is required.

[0166] The method for calculating riverbed scouring and coarsening based on the Han Qiwei method provided in this example can accurately calculate the thickness of the coarsening layer, the ultimate scouring depth, and the grading of the coarsening layer of pebble riverbeds and pebble-sand mixed riverbeds. This method predicts the riverbed scouring process through quantitative analysis of hydraulic conditions and bed sediment grading, and has high engineering application value.

[0167] In this embodiment, a device for determining riverbed scouring and coarsening parameters is also provided. This device is used to implement the above embodiments and preferred implementation manners, and those that have been described will not be repeated. As used hereinafter, the term "module" can be a combination of software and / or hardware that realizes a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware is also possible and contemplated.

[0168] This embodiment provides a device for determining riverbed scouring and coarsening parameters, as Figure 4 shown, the device includes:

[0169] An acquisition module 401, configured to acquire an initial riverbed scouring parameter set and an initial scouring step length under initial water flow conditions.

[0170] A first determination module 402, configured to determine a target water flow condition based on the initial riverbed scouring parameter set and the initial scouring step length, and process them through a preset adjustment method.

[0171] A calculation module 403, configured to calculate the critical non-scouring particle size and the initial cumulative grading under the target water flow condition based on a preset incipient motion velocity relation formula and the initial riverbed scouring parameter set, using the bisection method and the linear interpolation method.

[0172] An adjustment module 404, configured to calculate the characteristic particle size of the riverbed bed sediment under the target water flow condition and adjust the initial cumulative grading by using a preset calculation method for bed sediment grading coarsening during bed load scouring to obtain a target cumulative grading.

[0173] A second determination module 405, configured to determine a target riverbed scouring and coarsening parameter set based on the target water flow condition when the target cumulative grading is less than a preset threshold.

[0174] In some alternative implementation manners, the first determination module 402 includes:

[0175] A first calculation sub-module, configured to calculate the scouring percentage based on the initial riverbed scouring parameter set and the initial scouring step length.

[0176] An adjustment sub-module, configured to separately adjust the river depth and river velocity in the initial riverbed scouring parameter set to obtain the actual water depth and the actual water velocity.

[0177] The first determination sub-module is configured to determine the target water flow condition based on the scouring percentage, the actual water depth, and the actual water flow velocity.

[0178] In some alternative embodiments, the calculation module 403 includes:

[0179] An acquisition sub-module, configured to acquire a preset incipient flow velocity relation formula.

[0180] The second determination sub-module is configured to determine the calculation method for the coarsening gradation of the erosion-resistant layer based on the target water flow condition.

[0181] The second calculation sub-module is configured to calculate the critical non-scouring particle size under the target water flow condition by using the bisection method and the linear interpolation method based on the preset incipient flow velocity relation formula and the initial river channel scouring parameter set.

[0182] The third calculation sub-module is configured to calculate the initial cumulative gradation under the target water flow condition by using the calculation method for the coarsening gradation of the erosion-resistant layer based on the critical non-scouring particle size.

[0183] In some alternative embodiments, the acquisition sub-module includes:

[0184] An acquisition unit, configured to acquire the incipient standard of the riverbed sediment.

[0185] The first determination unit is configured to determine the incipient flow velocity relation formula at the riverbed bottom based on the incipient standard of the riverbed sediment.

[0186] The second determination unit is configured to determine the preset incipient flow velocity relation formula based on the incipient flow velocity relation formula at the riverbed bottom and the correlation of the scouring parameters.

[0187] In some alternative embodiments, the device further includes:

[0188] An iteration module, configured to modify the initial scouring step length when the target cumulative gradation is greater than a preset threshold, and re-determine the target water flow condition, and iterate repeatedly until the target cumulative gradation is greater than the preset threshold and the target river channel scouring coarsening parameter set is obtained.

[0189] In some alternative embodiments, the calculation method for the coarsening gradation of the erosion-resistant layer includes the pebble coarsening gradation method and the pebble-sand mixture coarsening gradation method.

[0190] The further function descriptions of the above-mentioned modules and units are the same as those in the corresponding embodiments above, and will not be elaborated herein.

[0191] The device for determining the river channel scouring and coarsening parameters in this embodiment is presented in the form of functional units. Here, the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and a memory that execute one or more software or fixed programs, and / or other devices that can provide the above functions.

[0192] An embodiment of the present invention further provides a computer device having the above-mentioned Figure 4 device for determining the river channel scouring and coarsening parameters.

[0193] Please refer to Figure 5 , Figure 5 which is a schematic structural diagram of a computer device provided by an optional embodiment of the present invention. As shown in Figure 5 , the computer device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including a high-speed interface and a low-speed interface. Each component communicates with each other using different buses and can be installed on a common motherboard or installed in other ways as needed. The processor can process instructions executed within the computer device, including instructions stored in the memory or on the memory to display graphical information of the GUI on an external input / output device (such as a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories. Similarly, multiple computer devices can be connected, and each device provides some necessary operations (such as an array of servers, a set of blade servers, or a multi-processor system). Figure 5 In

[0194] a single processor 10 is taken as an example.

[0195] The memory 20 stores instructions executable by at least one processor 10, so that at least one processor 10 executes the method shown in the above embodiment.

[0196] The memory 20 may include a program storage area and a data storage area. Among them, the program storage area can store an operating system and application programs required for at least one function; the data storage area can store data created according to the use of the computer device and the like. In addition, the memory 20 may include high-speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, a flash memory device, or other non-transitory solid-state storage devices. In some alternative embodiments, the memory 20 may optionally include a memory remotely provided with respect to the processor 10, and these remote memories can be connected to the computer device through a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0197] The memory 20 may include volatile memory, for example, random access memory; the memory may also include non-volatile memory, for example, flash memory, a hard disk, or a solid-state drive; the memory 20 may further include a combination of the above types of memory.

[0198] The computer device further includes a communication interface 30 for the computer device to communicate with other devices or a communication network.

[0199] The embodiments of the present invention also provide a computer-readable storage medium. The methods according to the embodiments of the present invention can be implemented in hardware, firmware, or be implemented as computer code that can be recorded on a storage medium, or be implemented as computer code originally stored in a remote storage medium or a non-transitory machine-readable storage medium and to be downloaded through a network and stored in a local storage medium, so that the methods described herein can be stored in such software processes on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disc, a read-only memory, a random access memory, a flash memory, a hard disk, or a solid-state drive, etc.; further, the storage medium may also include a combination of the above types of memory. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code, and when the software or computer code is accessed and executed by the computer, the processor, or the hardware, the methods shown in the above embodiments are implemented.

[0200] A part of the present invention can be applied as a computer program product, such as computer program instructions, which, when executed by a computer, can invoke or provide the methods and / or technical solutions according to the present invention through the operations of the computer. Those skilled in the art should understand that the forms of existence of computer program instructions in a computer-readable medium include, but are not limited to, source files, executable files, installation package files, etc. Correspondingly, the ways in which computer program instructions are executed by a computer include, but are not limited to: the computer directly executes the instructions, or the computer compiles the instructions and then executes the corresponding compiled program, or the computer reads and executes the instructions, or the computer reads and installs the instructions and then executes the corresponding installed program. Herein, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible by the computer.

[0201] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for determining the parameters of river channel scour and coarsening, characterized in that, The method includes: Obtaining an initial river channel scour parameter set and an initial scour step length under initial water flow conditions; Based on the initial river channel scour parameter set and the initial scour step length, through processing by a preset adjustment method, determining target water flow conditions; Based on a preset incipient velocity relationship and the initial river channel scour parameter set, using the bisection method and the linear interpolation method to calculate the critical non-scouring particle size and the initial cumulative gradation under the target water flow conditions; Using a preset calculation method for the coarsening of the bed sediment gradation during the transport of bed load, calculating the characteristic particle size of the riverbed bed sediment under the target water flow conditions and adjusting the initial cumulative gradation to obtain a target cumulative gradation; When the target cumulative gradation is less than or equal to a preset threshold, determining a target river channel scour coarsening parameter set based on the target water flow conditions.

2. The method according to claim 1, wherein Based on the initial river channel scour parameter set and the initial scour step length, through processing by a preset adjustment method, determining target water flow conditions, including: Calculating a scour percentage based on the initial river channel scour parameter set and the initial scour step length; Respectively adjusting the river channel water depth and the river channel velocity in the initial river channel scour parameter set to obtain an actual water depth and an actual velocity; Determining the target water flow conditions based on the scour percentage, the actual water depth, and the actual velocity.

3. The method according to claim 1, wherein Based on a preset incipient velocity relationship and the initial river channel scour parameter set, using the bisection method and the linear interpolation method to calculate the critical non-scouring particle size and the initial cumulative gradation under the target water flow conditions, including: Obtaining the preset incipient velocity relationship; Determining a calculation method for the coarsening gradation of the erosion-resistant layer based on the target water flow conditions; Based on the preset incipient velocity relationship and the initial river channel scour parameter set, using the bisection method and the linear interpolation method to calculate the critical non-scouring particle size under the target water flow conditions; Based on the critical non-scouring particle size, using the calculation method for the coarsening gradation of the erosion-resistant layer to calculate the initial cumulative gradation under the target water flow conditions.

4. The method according to claim 3, wherein Obtaining the preset incipient velocity relationship, including: Obtaining the standard for the incipient motion of riverbed sediment; Based on the standard for the incipient motion of riverbed sediment, determining the relationship for the incipient velocity at the riverbed bottom; Based on the relationship for the incipient velocity at the riverbed bottom and the correlation of scour parameters, determining the preset incipient velocity relationship.

5. The method according to claim 1, wherein The method further includes: When the target cumulative gradation is greater than the preset threshold, modifying the initial scour step length and re-determining the target water flow conditions, and iterating repeatedly until the target cumulative gradation is greater than the preset threshold and obtaining the target river channel scour coarsening parameter set.

6. The method according to claim 3, wherein The calculation method for the coarsening gradation of the erosion-resistant layer includes a cobble coarsening gradation method and a cobble-sand mixture coarsening gradation method.

7. An apparatus for determining river channel scour and coarsening parameters, characterized in that, The device includes: An acquisition module, configured to acquire an initial river channel scour parameter set and an initial scour step length under initial water flow conditions; A first determination module, configured to determine target water flow conditions based on the initial river channel scour parameter set and the initial scour step length through processing by a preset adjustment method; A calculation module, configured to calculate the critical non-scouring particle size and the initial cumulative gradation under the target water flow conditions based on a preset incipient velocity relationship and the initial river channel scour parameter set, using the bisection method and the linear interpolation method; An adjustment module, configured to calculate the characteristic particle size of the riverbed bed material under the target water flow condition and adjust the initial cumulative gradation by using a calculation method for the coarsening of the bed material gradation during the preset bed load scouring process, so as to obtain a target cumulative gradation; A second determination module, configured to determine a target river channel scouring coarsening parameter set based on the target water flow condition when the target cumulative gradation is less than a preset threshold.

8. A computer device, characterized in that, Comprising: A memory and a processor, which are communicatively connected to each other. The memory stores computer instructions, and the processor executes the computer instructions to execute the river channel scouring coarsening parameter determination method according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, Computer instructions are stored on the computer-readable storage medium, and the computer instructions are used to cause a computer to execute the river channel scouring coarsening parameter determination method according to any one of claims 1 to 6.

10. A computer program product, characterized in that, Comprising computer instructions, and the computer instructions are used to cause a computer to execute the river channel scouring coarsening parameter determination method according to any one of claims 1 to 6.

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