Method for calculating void scale caused by loss of soil under pump station bottom plate and electronic equipment

Abstract

The invention relates to the technical field of water conservancy projects, and particularly discloses a method for calculating the void scale caused by soil loss under a pump station bottom plate and electronic equipment, and the method comprises the steps: determining the maximum water head difference of two sides of a pump station, the soil particle density and the total length of the pump station bottom plate, and estimating the diameter of a gap channel; and carrying out stress analysis on the microcosmic soil particle units on the side wall of the gap channel, wherein the stress comprises effective gravity, drag force, seepage force, lifting force, cohesive force, supporting force, sliding friction force and rolling friction moment. According to the method for calculating the void scale caused by soil loss under the pump station bottom plate, a particle kinetic method is introduced, gap channel water flow under the bottom plate is regarded as pressure pipe flow, particle stress analysis, a sliding / rolling instability mode and a Kolbolok-White formula of a turbulent flow hydraulic transition area are comprehensively considered, and the void scale caused by soil loss under the pump station bottom plate is calculated. The length of the void development channel can be quickly calculated based on engineering parameters, and the void position and the risk range can be determined.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydraulic engineering, and in particular to a method for calculating the scale of soil loss caused by voiding under the bottom plate of a pump station and an electronic device. BACKGROUND

[0002] In the field of hydraulic engineering, voiding caused by soil loss under the bottom plate of a pump station is common, especially large-scale voiding frequently found during maintenance of gates and pump stations on soft foundations. If not promptly addressed, it can lead to weakened ground strength, formation of water inrush channels, expansion of voiding areas, and piping, among other safety hazards.

[0003] The prior art lacks a method for quickly and cost-effectively predicting the scale of soil loss voiding under the bottom plate of a pump station, especially under pressure flow conditions. It is unable to effectively calculate the length and risk range of the voiding development channel by combining particle kinetics and hydraulic slope characteristics, resulting in a lack of precise technical support for engineering safety assessment and risk prevention and control. SUMMARY

[0004] The present application aims to at least partially address one of the technical problems in the related art. To this end, the purpose of the present application is to provide a method for calculating the scale of soil loss voiding under the bottom plate of a pump station and an electronic device to improve the reliability and efficiency of engineering safety assessment.

[0005] To achieve the above-mentioned purpose, the first aspect of the present application provides a method for calculating the scale of soil loss voiding under the bottom plate of a pump station, which comprises the following steps:

[0006] determining the maximum water head difference on both sides of the pump station , soil particle density , total length of the pump station bottom plate , and estimating the diameter of the void channel ;

[0007] performing force analysis on the microscopic soil particle units of the void channel side wall, including effective gravity , drag force , seepage force , uplift force , cohesive force , support force , sliding friction force , and rolling friction torque ;

[0008] calculating the seepage force under the hydraulic slope conditions of the void channel ;

[0009] determining the cohesive force using the Shields curve assumption ;

[0010] The critical starting flow velocity formula and the torque balance formula of soil particle rolling instability are derived respectively;

[0011] The critical along-path loss factor is solved by using Colebrook-White formula , and the void channel length is calculated , and then the scale of void is determined.

[0012] In some embodiments of the present application, the effective gravity The calculation formula is as follows:

[0013] ;

[0014] Wherein, The density of water is, The particle size of soil particle is calculated, The gravity acceleration is.

[0015] In some embodiments of the present application, the calculation formula of the lifting force The calculation formula is as follows:

[0016] ;

[0017] Wherein, The lifting force coefficient is, The instantaneous flow velocity acting on the particle is.

[0018] In some embodiments of the present application, the calculation formula of the drag force The calculation formula is as follows:

[0019] ;

[0020] Wherein, The drag force coefficient is.

[0021] In some embodiments of the present application, the calculation formula of the seepage force The calculation formula is as follows:

[0022] ;

[0023] Wherein, The seepage force shape coefficient is, The hydraulic gradient of the seepage field is, and , The along-path water head loss is, The seepage field distance is.

[0024] In some embodiments of the present application, the calculation formula of the cohesive force The calculation formula is as follows:

[0025] ;

[0026] in, This is the adhesion coefficient.

[0027] In some embodiments of the present invention, the critical initiation velocity formula for the soil particles to undergo sliding instability satisfies:

[0028] ;

[0029] in, The internal friction angle between soil particles. The angle between the seepage force and the horizontal direction.

[0030] In some embodiments of the present invention, the relationship between the critical starting velocity and the frictional velocity is expressed as follows:

[0031] ;

[0032] Derivation of the critical average starting velocity for soil particle sliding instability ,in, For frictional flow velocity, The height of the bed surface roughness. The surface roughness is equal to the particle size of the soil. for The function, For the thickness of the viscous base layer, This is a correction factor for the exposure of sediment particles;

[0033] For uneven sediment particles, take , , The particle size of the sediment is denoted as .

[0034] In some embodiments of the present invention, the moment balance equation for the rolling instability of the soil particles is as follows:

[0035] ;

[0036] in, The vertical resultant force is the horizontal distance from the point of rotation. It is the vertical distance from the resultant horizontal force to the pivot point of rotation.

[0037] In some embodiments of the present invention, the Colebrook-White formula is as follows:

[0038] ;

[0039] in, Let be the absolute roughness of the sidewall. Let be the Reynolds number, and , is the average flow velocity of the pipeline section at the starting moment, is the kinematic viscosity;

[0040] The method for determining the scale of the void is: substituting the critical friction loss factor into the Darcy-Weisbach formula:

[0041]

[0042] The length of the void channel is calculated as combined with the elliptical shape of the void, the void area is calculated as the long axis, the void risk range is determined, is the critical average flow velocity.

[0043] To achieve the above object, the second aspect of the embodiment of the present application provides an electronic device, which comprises a memory, a processor and a computer program stored in the memory, and the computer program is executed by the processor to realize the method for calculating the scale of the void caused by the soil loss under the pump station floor.

[0044] The method for calculating the scale of the void caused by the soil loss under the pump station floor and the electronic device provided by the embodiment of the present application can quickly calculate the length of the void development channel, determine the void position and the risk range based on the engineering parameters, by introducing the particle starting mechanics method, regarding the water flow in the void channel under the floor as a pressurized pipe flow, and comprehensively considering the particle force analysis, the sliding / rolling instability mode and the Colebrook-White formula in the turbulent hydraulic transition zone. The method provides a low-cost technical means for the development of the protection measures before the construction of the pump station and the prediction of the void risk during the operation period, and can effectively assist the engineering safety evaluation and provide a reference for the long-term operation and maintenance. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 is the flowchart of the method for calculating the scale of the void caused by the soil loss under the pump station floor in the embodiment of the present application;

[0046] Figure 2 is the schematic diagram of the force analysis of the soil particles in the embodiment of the present application;

[0047] Figure 3 is the analysis schematic diagram of the sliding and rolling critical average starting flow velocity in the embodiment of the present application;

[0048] Figure 4 is the calculation result schematic diagram of the second embodiment of the present application;

[0049] Figure 5 is the structure schematic diagram of the electronic device in another embodiment of the present application. DETAILED DESCRIPTION ​​

[0050] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0051] The following describes, with reference to the accompanying drawings, a method for calculating the scale of voids caused by soil erosion under the pump station floor slab according to an embodiment of the present invention, and an electronic device.

[0052] Figure 1 This is a flowchart illustrating a method for calculating the scale of voids caused by soil erosion under the foundation slab of a pumping station, according to an embodiment of the present invention.

[0053] Example 1:

[0054] like Figure 1 As shown, a method for calculating the scale of voids caused by soil erosion under the foundation slab of a pumping station includes the following steps:

[0055] S1. Determine the maximum head difference between the two sides of the pumping station. Soil particle density Total length of pump station base plate And estimate the diameter of the void channel. These parameters are the fundamental inputs for all subsequent calculations, including the head difference. The driving force of seepage is determined by soil particle density. The diameter of the void channel affects the force analysis of particles. Related particle initiation force and channel hydraulic characteristics, total length of bottom plate The S1 step serves as a boundary reference for the spatial range of the voiding scale. By clarifying the basic engineering and medium parameters, it provides initial conditions for subsequent particle stress analysis, seepage force calculation, and voiding channel simulation, and is a prerequisite for achieving quantitative calculation of the voiding scale.

[0056] As an example, assume that the soil particles filling the void channel under the pump station base are spherical. The particles on the channel sidewall are located at the interface between solid particles and liquid water flow, and are subjected to the combined effects of seepage from the soil below and scouring from the water flow in the void channel above. A micro-sized soil particle element on the channel sidewall is taken as the research object for stress analysis.

[0057] S2. Perform a stress analysis on the micro-grain elements of the pore channel sidewalls, including effective gravity. Drag force seepage force Lifting force Adhesion Support Sliding friction And rolling friction torque The force on the particle is the core basis for determining whether it is unstable (leaving the channel side wall into the water flow, pushing the development of the void). The balance relationship of different forces (such as drag force, seepage force driving particle movement, cohesive force, friction force hindering movement) directly determines the particle starting condition, and then affects the "source power" analysis of soil loss in the void channel. This step comprehensively analyzes the force system mechanism of particle instability from the perspective of micromechanics, breaking through the simplification limitations of traditional macroscopic methods for complex factors of particle starting, and laying a mechanical foundation for accurately deriving the critical starting condition.

[0058] S3, calculate the seepage force combined with the hydraulic gradient condition of the gap channel The seepage force is one of the key driving forces for particle movement, and the hydraulic gradient reflects the change of water head loss along the channel, which is related to the water head difference in step 1 (The hydraulic gradient is determined by the total water head difference and the length distribution of the channel), and its calculation result is directly substituted into the force balance equation in step 2 to affect the particle starting judgment. Further, the macroscopic hydraulic conditions (water head difference, channel shape) are related to the microscopic particle force (seepage force), realizing the quantitative influence analysis of hydraulic parameters on particle instability, and making up for the shortcomings of ignoring the seepage field distribution by relying on experience or simplified formula.

[0059] S4, determine the cohesive force by assuming the Shields curve The cohesive force is the key force that hinders the particle instability, and the Shields curve is based on the classic theory of sediment starting, which relates particle size, bed shear force and other parameters, combined with the particle force analysis in step 2 (as part of the anti-instability force), to determine whether the particle can overcome the cohesive force and separate from the channel side wall under the action of seepage. This step introduces the mature sediment starting theory to reasonably quantify the cohesive force between particles, solving the problem of difficult direct measurement and quantitative calculation of the cohesive force of microscopic particles, and improving the scientific nature of particle instability judgment.

[0060] S5, derive the critical starting flow formula of soil particles when sliding instability and rolling instability occur respectively. Based on the force analysis in step 2 (force and torque balance), combined with the calculation results of step 3 (seepage force) and step 4 (cohesive force), the critical condition of particle "dynamic-static" conversion is established. Sliding and rolling instability are two typical modes of particle separation from the channel side wall, and their formula provides a basis for the "critical flow threshold" of subsequent judgment of soil loss in the channel, and relates the triggering relationship between water flow velocity and soil loss in the void channel.

[0061] This method starts from two instability modes, accurately defines the hydraulic conditions of particle starting, breaks through the limitations of single instability assumption, and makes the starting criterion of soil loss in the void channel more in line with actual complex working conditions.

[0062] S6. Solve for the critical friction loss factor using the Colebrook-White formula. And calculate the gap channel length. This allows for the determination of the scale of the air gap. The Colebrook-White formula relates the flow loss along the channel (to the head difference in step 1). In step 5, the critical velocity is correlated with the influence of friction loss on the hydraulic gradient distribution and the channel roughness characteristics, through the critical friction loss factor. Calculate channel length Combined with the total length of the base plate and the diameter of the gap channel Ultimately, the scale of voiding (such as area and volume) is quantified. This is a crucial derivation step from the microscopic conditions of particle initiation to the calculation of the macroscopic scale of voiding. Step S6 integrates hydraulic calculations (friction loss, critical velocity) with engineering geometric parameters (channel diameter, bottom plate length), achieving a leap from particle instability analysis to quantitative calculation of voiding scale, providing directly applicable quantitative results for voiding risk assessment and protective measure design in engineering practice.

[0063] The derivation of the above steps, from basic parameter input, micromechanical analysis, hydraulic-mechanical coupling calculation, to the final quantification of the voiding scale, constructs a complete logical chain of "micro-particle instability driving - macro-channel development - voiding scale definition". This solves the problem that existing technologies are unable to accurately calculate the voiding scale under the pump station floor, and provides a scientific method for engineering safety assessment and management.

[0064] In some embodiments of the present invention, effective gravity This refers to the gravitational force experienced by a particle underwater, and its calculation formula is:

[0065] ; (1)

[0066] in, The density of water, To calculate soil particle size, This is the acceleration due to gravity.

[0067] In some embodiments of the present invention, the lifting force This force is generated by the difference in flow velocity between the top and bottom of the particles in the water, and its calculation formula is:

[0068] ; (2)

[0069] in, This is the lifting force coefficient. The instantaneous flow velocity acting on the particles.

[0070] In some embodiments of the present invention, drag force is the force generated by the friction between the water flow and the particles and the pressure difference before and after the particles, and its calculation formula is:

[0071] ; (3)

[0072] wherein, is the drag coefficient.

[0073] In some embodiments of the present application, when the force analysis is performed in step S2, the seepage force generated on one side of the soil body needs to be calculated in combination with the hydraulic gradient condition of the floor gap channel. Different thicknesses of soil bodies have different pore water pressures, and the pressure gradient direction is everywhere perpendicular to the bed surface upward, thus promoting the start of the soil particles. Then the calculation formula of the seepage force is:

[0074] ; (4)

[0075] wherein, is the shape coefficient of the seepage force, is the hydraulic gradient of the seepage field, ;

[0076] Here, ; (5)

[0077] wherein, is the head loss along the way, is the distance of the seepage field.

[0078] In some embodiments of the present application, the mechanism of the cohesive force between soil particles is complex, and the current domestic and foreign research has relatively insufficient understanding, so it is difficult to give the formula of the cohesive force from the theoretical level. The related research is mainly based on empirical formula. Here, the commonly used assumption in the Shields curve method is adopted, and the cohesive force is expressed as the product of the cohesive force coefficient and the square of the particle size of the sediment , so the calculation formula of the cohesive force is:

[0079] ; (6)

[0080] In some embodiments of the present application, the mechanical analysis of the sliding instability and the rolling instability of the soil particles is carried out here, and the critical incipient velocity formula of the uniform sediment particles is derived.

[0081] wherein, the critical incipient velocity formula of the sliding instability of the soil particles satisfies:

[0082] ; (7)

[0083] wherein, is the internal friction angle between soil particles, is the seepage force is the angle between the horizontal direction and the seepage force.

[0084] The critical incipient velocity of soil particles to slide and lose stability is obtained from the calculation formula of each force is:

[0085] ; (8)

[0086] At this time, there is a relationship between the critical incipient velocity and the friction velocity:

[0087] ; (9)

[0088] wherein, is the friction velocity, is the bed surface roughness height, is the bed surface roughness rate, which is equal to the size of the soil particle diameter, is a function of, is the viscous sublayer thickness, is the exposure correction coefficient of sediment particles.

[0089] For non-uniform sediment particles, and usually is taken as the size of the sediment particle (roughness size). Here, is defined as a function of and takes is to eliminate the viscous sublayer thickness in the formula of the logarithmic velocity distribution law of turbulent flow near the wall, in other words, to regard the wall as a hydraulic rough wall (smooth wall only considers the influence of viscous sublayer, here it is non-uniform sediment particles, which can be directly regarded as a hydraulic rough wall).

[0090] The formula mentioned here "logarithmic velocity distribution law of turbulent flow near the wall" is also the logarithmic law expression form of the incipient velocity of sediment, that is, the boundary layer function commonly used in simulation, which is shown as follows:

[0091] ;

[0092] ;

[0093] Take , , substitute to obtain the critical average incipient velocity of soil particles to slide and lose stability .

[0094] ; (10)

[0095] where h is the water depth, here h is converted from the hydraulic radius, and in the calculation, H-dH is approximately taken, that is, the water head at the current position after deducting the head loss along the way.

[0096] Instead of The following can be obtained:

[0097] ; (11)

[0098] In some embodiments of the application, for rolling instability, only The action point on the soil particles is moved from the contact surface to the center of gravity of the particles, and the action force generates a couple moment, which The horizontal component of is recorded as the horizontal resultant force, and the moment is the vertical distance from the center of gravity of the particle to the rotation fulcrum, and the vertical component of the remaining force and is recorded as the vertical resultant force, and the moment is the horizontal distance from the center of gravity of the particle to the rotation fulcrum, and then the moment analysis is carried out. Further, the critical starting flow formula (moment balance equation) of the soil particles for rolling instability is obtained as:

[0099] ; (12)

[0100] where is the horizontal distance from the vertical resultant force to the rotation fulcrum, is the vertical distance from the horizontal resultant force to the rotation fulcrum.

[0101] Then substitute the force calculation formula to obtain the instantaneous bottom speed of the non-uniform sediment particles when rolling starts:

[0102] ; (13)

[0103] Let , and replace with the critical average starting flow of the soil particles for rolling instability to obtain:

[0104] ; (14)

[0105] Through the above calculation, the critical average starting flow of the soil particles for sliding instability and the critical average starting flow of the soil particles for rolling instability are obtained, and then the two are uniformly input into the following formula (15) and (16), and the size of the obtained results is compared, and the larger one is input into formula (17).

[0106] ​In some embodiments of the present application, the Colebrook-White formula fits well with the experimental results of the pressure flow in the turbulent transition zone, and the formula is:

[0107] ; (15)

[0108] wherein, is the critical friction loss factor, is the absolute roughness of the side wall, is the Reynolds number, which is an implicit equation;

[0109] and ; (16)

[0110] wherein, is the average flow velocity of the pipe section at the starting moment, is the kinematic viscosity.

[0111] The implicit equation is solved by methods such as Newton iteration method to obtain the critical friction loss factor . Then the critical loss factor is substituted into the Darcy-Weisbach formula, and the length of the void channel , i.e. the maximum length of the void development channel in the hydraulic slope direction, is calculated according to the maximum head loss, and the determination method of the void scale is:

[0112] ; (17)

[0113] wherein, is the head loss, is the critical average flow velocity.

[0114] The longest, the length of the void channel is calculated, combined with the void shape being an ellipse, the void area is calculated with the major axis , and the void risk range is determined.

[0115] Example Two:

[0116] This embodiment refers to Figure 2 , Figure 3 for stress analysis.

[0117] Step One: According to the data of a certain engineering project, the design maximum head difference H=6.0m on both sides of the pump station is determined, the soil particle density , and the total length of the pump station bottom plate L=185m. Assuming that the soil particle size distribution is uniform, d=0.35mm is taken.

[0118] The diameter of the void channel d=3.5mm is estimated, and the uplift coefficient Take 0.1; drag coefficient Take 0.42; seepage force shape coefficient Take 1.165; cohesion coefficient Take 2.7475; sliding internal friction angle 30°; the absolute roughness of the square resistance zone is taken as Δ = 0.005 m; the kinematic viscosity is taken as v = 1.004 × 10⁻ 6 m² / s; the seepage force angle is taken as α = 0.

[0119] Step two: substitute the required parameters in step one into formulas (1), (2), and (3) to obtain the self-effective gravity , drag force , and uplift force .

[0120] Step three: for convenience of calculation, the total length L of the pump station floor is divided into 37 parts, so the length of each floor is 5 meters, and two virtual nodes are set at the upstream and downstream floor boundaries, with node numbers from 0 to 37 (a total of 38 nodes). The shortest distance of each node from the upstream node in the hydraulic gradient direction is taken as the void channel length of the point. For each node, substitute the required parameters in step one and the channel length of the corresponding node into formulas (4) and (5), and combine the hydraulic gradient calculation method to obtain the distribution of seepage force in the hydraulic gradient direction.

[0121] Step four: substitute the required parameters in step one into formula (6) to obtain the cohesion .

[0122] Step five: substitute the above results into formulas (11) and (14) to obtain the critical average starting flow velocities and at which the soil particles just lose stability by sliding and rolling, respectively.

[0123] Step six: substitute the required parameters in step one and the critical average starting flow velocities and into formulas (15) and (16), take the larger of the obtained results as input into formula (17), and try to solve the implicit equation using the Newton iteration method. The result obtained is related to the void channel length , i.e., the maximum length of the potential void channel in the hydraulic gradient direction. Substitute the channel length of each node in step four, and solve the implicit equation using the Newton iteration method.

[0124] Through the above calculation, it is found that the maximum floor voiding possibly occurs at a position about upstream of the maximum water head difference in the hydraulic slope direction in the embodiment, and the area of the floor voiding risk range is about , and the floor voiding risk range is shown in Figure 4 .

[0125] Corresponding to the above embodiment, the application further provides an electronic device.

[0126] As shown in Figure 5 , it is a structural schematic diagram of an electronic device in the application, and the electronic device 200 includes a processor 201 and a memory 203. The processor 201 and the memory 203 are connected, for example, through a bus 202. Optionally, the electronic device 200 can further include a transceiver 204. It should be noted that the transceiver 204 is not limited to one in actual application, and the structure of the electronic device 200 does not constitute a limitation on the embodiments of the application.

[0127] The processor 201 can be a CPU, a general-purpose processor, a DSP, an ASIC, an FPGA or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. It can implement or execute various exemplary logical blocks, modules and circuits described in combination with the disclosure. The processor 201 can also be a combination of computing functions, such as one or more microprocessor combinations, DSP and microprocessor combinations, etc.

[0128] The bus 202 can include a channel for transmitting information between the above-mentioned components. The bus 202 can be a PCI bus or an EISA bus, etc. The bus 202 can be divided into an address bus, a data bus, a control bus, etc. For the convenience of representation, Figure 5 only one thick line is used, but it does not mean that there is only one bus or only one type of bus.

[0129] The memory 203 is used to store a computer program corresponding to the calculation method of the floor voiding scale caused by the soil loss of the pump station floor in the above-mentioned embodiments of the application, and the computer program is executed by the processor 201. The processor 201 is used to execute the computer program stored in the memory 203 to realize the content shown in the above-mentioned method embodiments.

[0130] The electronic device 200 includes but is not limited to mobile terminals such as notebook computers, PADs (tablet computers) and the like, and fixed terminals such as desktop computers and the like. Figure 5 The electronic device 200 shown is only an example, and should not limit the functions and use range of the embodiments of the application.

[0131] It is to be appreciated that the above description and the examples that follow are intended to be illustrative only and that changes can be made to the description and examples without departing from the scope of the application. Note also that the use of particular brand names in the description is solely for illustration and should not be construed as an endorsement of such brands.

[0132] It should be understood that aspects of the application can be implemented in hardware, software, firmware or combinations thereof. In the embodiments described above, various steps or methods can be implemented, in part, or in whole, in software and / or firmware that are stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, and in another embodiment, any of the following techniques, which are well known in the art, can be used to implement the application: a hybrid of the techniques mentioned above; a combination of one or more of the techniques mentioned above; or one or more other techniques suitable for use in the computer-based systems described above.

[0133] In the description of the present application, the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. The illustrative appearances of the above-mentioned terms in various places in the specification are not intended to exclude that each of the terms should be interpreted in the context of the specification as whole, but rather only to emphasize that a particular feature, structure, material or characteristic is included in at least one embodiment or example. Moreover, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0134] Furthermore, the terms "first", "second", etc. are used only for descriptive purposes and do not connote or imply relative importance or a quantity of the indicated technical features. Thus, a feature defined with "first", "second", etc. can include at least one of the features implicitly or explicitly. In the description of the present application, the meaning of "a plurality" is at least two, for example, two, three, etc., unless otherwise specifically defined.

[0135] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present application, and that changes, modifications, substitutions and variations can be made by those skilled in the art without departing from the scope of the present application.

Claims

1. A method for calculating the scale of voids caused by soil erosion under the foundation slab of a pumping station, characterized in that, Includes the following steps: Determine the maximum head difference between the two sides of the pumping station Soil particle density Total length of pump station base plate And estimate the diameter of the void channel. ; A stress analysis was performed on the micro-soil particle elements of the pore channel sidewall, the stress including effective gravity. Drag force seepage force Lifting force Adhesion Support Sliding friction and rolling friction torque ; Calculate seepage force based on hydraulic gradient conditions of the void channel ; Determining adhesion strength using the Shields curve assumption ; The critical starting velocity formula for soil particles to undergo sliding instability and the moment balance formula for soil particles to undergo rolling instability are derived respectively. Solving for the critical friction loss factor using the Colebrook-White formula And calculate the gap channel length. This allows us to determine the scale of the destocking process.

2. The method according to claim 1, characterized in that, The effective gravity The calculation formula is: ； in, The density of water, To calculate soil particle size, This is the acceleration due to gravity.

3. The method according to claim 1, characterized in that, The lifting force The calculation formula is: ； in, This is the lifting force coefficient. The instantaneous flow velocity acting on the particles.

4. The method according to claim 1, characterized in that, The drag force The calculation formula is: ； in, This is the drag force coefficient.

5. The method according to claim 1, characterized in that, The seepage force The calculation formula is: ； in, The shape factor is the seepage force. For the hydraulic gradient of the seepage field, and , For head loss along the route, The distance is the seepage field distance.

6. The method according to claim 1, characterized in that, The adhesive force The calculation formula is: ； in, This is the adhesion coefficient.

7. The method according to claim 1, characterized in that, The formula for the critical starting velocity at which the soil particles undergo sliding instability satisfies: ； in, The internal friction angle between soil particles. The angle between the seepage force and the horizontal direction.

8. The method according to claim 7, characterized in that, The relationship between critical starting velocity and frictional velocity is as follows: ； Derivation of the critical average starting velocity for soil particle sliding instability ,in, For frictional flow velocity, The height of the bed surface roughness. The surface roughness is equal to the particle size of the soil. for The function, For the thickness of the viscous base layer, This is a correction factor for the exposure of sediment particles; For uneven sediment particles, take , , The particle size of the sediment is denoted as .

9. The method according to claim 1, characterized in that, The moment balance equation for the rolling instability of the soil particles is: ； in, The vertical resultant force is the horizontal distance from the point of rotation. It is the vertical distance from the resultant horizontal force to the pivot point of rotation.

10. The method according to claim 1, characterized in that, The Colebrook-White formula is as follows: ； in, Let be the absolute roughness of the sidewall. It is the Reynolds number, and , The average flow velocity across the pipe cross-section at the moment of startup. Kinematic viscosity; The method for determining the scale of the vacancy is as follows: The critical friction loss factor is used... Substituting into the Darcy-Weisbach formula: ； Calculate the length of the gap channel Combined with the elliptical shape of the hollowed-out form, with Calculate the void area for the major axis Determine the scope of risk of being delisted. It is the critical average velocity.

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