System and method for analyzing dam break of barrier lake based on erosion obstruction

Abstract

The invention discloses a barrier lake break analysis system and method based on erosion obstruction, and relates to the technical field of disaster prediction of water conservancy and geological engineering, and the system comprises a user interface module which allows a user to input parameters, and starts each function module and a visual result; the data processing module is responsible for simulating the dam break process considering the erosion blocking effect; the data management module is used for checking, storing and exporting data; in the data processing module, relevant parameters are called, lake water level changes are updated according to the time step length, corresponding outburst parameters are calculated through an established model, meanwhile, the slope stability of the breach is verified, and the critical elevation and the critical slope toe are judged. Therefore, by the adoption of the dam break analysis system and method for the barrier lake based on erosion obstruction, the precision of the water level, the breach flow and the geometric change data of the dam body and the breach can be improved, meanwhile, through modular design, smooth parameter interaction and data visualization are achieved, and the system and method have good disaster early warning application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of water conservancy and geological engineering disaster prediction, and in particular to a barrier lake dam-break analysis system and method based on hindering erosion. Background Art

[0002] For the prediction of dam-break process of barrier lake, relying only on empirical formula and comparative analysis can no longer meet the actual needs. On this basis, the model based on dam-break mechanism has been rapidly developed.

[0003] When water gradually accumulates in front of the barrier dam until the reservoir water level reaches the height of the dam body, overtopping and breaching occurs. As the breaching water flows downward along the dam body, it will erode the dam body. Considering the characteristics of the dam breaching water flow, the changes in the erosion process can be described more specifically and accurately, which is of great significance for the accurate prediction of the dam breaching process.

[0004] The flow velocity of the water flow in the dam burst is fast, which belongs to the rapid water flow. When it erodes the dam body, it is manifested as the whole particles starting to move, that is, the top layer of sediment starts to move in layers. From a mechanical point of view, the starting sediment layer shows shear expansion, the porosity increases, and the seepage enters the pores of the soil. Due to this infiltration effect, the sediment is not easily eroded.

[0005] However, the existing erosion models do not take this hindering erosion effect into account. Therefore, it is necessary to provide a new erosion model that considers hindering erosion to explore the dam-break process of the barrier lake and improve the accuracy of prediction. Summary of the invention

[0006] The purpose of the present invention is to provide a barrier lake dam break analysis system and method based on erosion barrier, which can obtain high-precision dam break parameters and realize parameter interaction and data sharing between modules.

[0007] To achieve the above-mentioned purpose, the present invention provides a barrier lake dam break analysis system and method based on erosion prevention, comprising: The user interface module includes parameter input, data transmission and reception, data visualization, and result export functions, allowing users to input parameters, start various functional modules, and visualize results; Data processing module, including lake area-water level curve fitting module and dam-break process simulation module. This module is built based on the barrier lake dam-break model that hinders erosion effect and is responsible for simulating the dam-break process; The data management module is responsible for verifying, storing and exporting data, saving the data in a structure, and generating a file for the user to download when receiving an export instruction.

[0008] Preferably, the lake area-water level curve fitting module is used to call the lake area-water level data and use the fitting data tool to generate fitting data of the water level-area relationship.

[0009] Preferably, the dam-break process simulation module is responsible for simulating the dam-break process at different times, and obtaining relevant dam-break parameters based on time series through cyclic calculations.

[0010] Preferably, the barrier lake dam breach model based on the erosion barrier effect includes establishing an erosion model based on the erosion barrier effect, hydraulic analysis and breach evolution; Among them, the erosion model based on the barrier erosion effect is expressed as follows: ; In the formula, , is the erosion rate, is the relative density, is the median particle size of sediment, is the acceleration due to gravity, is a dimensionless number, It is a parameter that characterizes the state of sediment movement; A coefficient that reflects the damping of turbulence in the near-bed area where the sand concentration is extremely high, the increase in kinematic viscosity, and the shear dilatancy behavior at the top of the sand bed; In hydraulic analysis, an expression for water level is obtained from a capacity or area curve; In breach evolution, the breach evolution under continuous erosion is simulated, including the elevation change of the breach bottom and the lateral change of the breach.

[0011] Preferably, The expression is: ; In the formula, is the dimensionless water flow shear force.

[0012] Preferably, the data management module includes data verification, data transmission and storage, and data export functions; Among them, the data verification function is used to check the validity of the received data, including value type check, value range check and data anomaly check; Data transfer and storage functions are used to store received data into a structure for use by the data processing module and the user interface module; The data export function is used to receive export instructions, establish a table corresponding to the instruction format, extract the data in the structure, distribute them to independent worksheets by category, and save them to the specified directory.

[0013] A barrier lake dam-break analysis method based on erosion prevention includes the following steps: S1. Input relevant parameters through the user interface module, package them into a structure, and pass them to the data processing module; S2, the data processing module calls the input parameters, first uses the lake area-water level curve fitting module to obtain the fitting data of the water level-area relationship, and then outputs it to the dam break process simulation module to simulate the break process at different times, and obtains the relevant break parameters based on the time series through cyclic calculation; S3. The user interface module generates and visualizes the change curve of the corresponding collapse parameter according to the processing results of the data processing module.

[0014] Preferably, step S2 comprises: S21, reading relevant input parameters in the user interface module, wherein the relevant input parameters include lake area-water level data, initial dam crest height, initial water level, residual dam height, initial breach depth and width, backwater slope angle, frontwater slope angle, critical backwater slope foot, inflow, particle bulk density, D50, D90, internal friction angle, cohesion, time step, and number of cycles; S22, update the time step according to the time step length, and judge whether the lake water level is greater than the bottom elevation of the breach; if so, calculate the flow of water through the breach within the time step by using the broad-top weir flow formula, and calculate the change of the water level of the barrier lake within the time step according to the water balance equation, and use the calculated flow and water level to update and store; otherwise, set the breach flow to 0, calculate the change of the water level of the barrier lake within the time step according to the water balance equation, and return to make a new judgment; S23, calling the flow and related input parameters, using the erosion model to calculate the breach erosion amount within the time step, and calculating the amount of cut-off at the bottom of the breach and the lateral widening at the top and bottom of the breach through the erosion amount, and calculating the corresponding breach elevation and width values; S24, verify the stability of the breach slope in each time step. When the driving force is less than or equal to the resistance, the breach slope is judged to be stable; when the driving force is greater than the resistance, the breach slope is judged to be unstable, and the breach slope angle becomes half of the sum of the rupture angle and the steepest stable slope angle; S25, determining whether the elevation of the bottom of the breach is less than the critical elevation; if so, setting the elevation of the bottom of the breach equal to the critical elevation; otherwise, using the calculated breach size of the barrier dam to update and store; S26, call the bottom elevation of the breach, and calculate the length and width of the backwater slope foot and the dam crest along the river according to the geometric relationship; S27, judging whether the toe of the back slope is greater than or equal to the critical toe; if so, setting the toe of the back slope equal to the critical toe; otherwise, using the calculated toe of the back slope and the length and width of the dam crest along the river to update and store; S28. Repeat steps S21 to S25 according to the set number of cycles until the predetermined cycle conditions are reached, and transfer the stored results to the data management module.

[0015] Preferably, when verifying the stability of the breach slope, the safety factor To determine the magnitude of driving force and resistance, the expression is as follows: ; in, ; ; In the formula, is the stabilizing force, i.e. resistance; It is a non-stabilizing force, i.e., a driving force; , are the slope gradients before and after the breach slope was destroyed; is the slope height, is the weight of the failed block, is the volume ratio, is the friction angle, For soil cohesion.

[0016] Therefore, the present invention adopts the above-mentioned barrier lake dam break analysis system and method based on hindering erosion, which has the following technical effects: (1) Taking into account the erosion barrier effect and establishing an erosion model, more accurate data on water level, breach flow, dam body and breach geometry can be obtained. At the same time, the stability of the breach slope can be verified and the critical elevation and critical slope foot can be determined, which can ensure the reliability of the data.

[0017] (2) Through modular design, smooth parameter interaction and data visualization can be achieved among the user interface module, data processing module, and data management module, which has good application prospects in disaster warning.

[0018] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of a barrier lake dam-break analysis system based on hindering erosion; Figure 2 It is a flow chart of the dam-break analysis method of barrier lake based on barrier erosion. DETAILED DESCRIPTION

[0020] The present invention can be explained in more detail by the following examples. The purpose of disclosing the present invention is to protect all changes and improvements within the scope of the present invention. The present invention is not limited to the following examples.

[0021] like Figure 1 As shown, based on the dam-break model, the present invention provides a barrier lake dam-break analysis system based on hindering erosion, including: 1. User interface module, including parameter input, data transmission and reception, data visualization, and result export functions, allowing users to input parameters, start each module and visualize results, so that users can easily operate each functional module and obtain visualized data more intuitively.

[0022] Parameter input: In the user interface module, an input control area is provided for users to input the parameters required for calculation, including lake area-water level data, initial dam crest height, initial water level, residual dam height, initial breach depth and width, backwater slope angle, frontwater slope angle, critical backwater slope foot, inflow, particle bulk density, , , internal friction angle, cohesion, time step, and number of cycles.

[0023] Data transmission and reception: Pack all parameters input by the user into a structure to ensure the integrity of each parameter; pass the structure from the user interface module to the data processing module to ensure that the data processing module can obtain and use the parameters input by the user; receive the result data generated by the data processing module, and parse each result into the corresponding visualization window.

[0024] Data visualization: Generate corresponding change curves based on the processing result data of the data processing module to realize data visualization; specifically including: lake area-water level curve, breach flow curve, breach width change curve, breach elevation change curve, dam body geometry and breach geometry.

[0025] The export function allows users to save the calculation results as files for subsequent analysis and use. Specifically, users can choose the format of the export file to meet different needs; the system packages all the calculated data, including the lake area-water level relationship, breach flow data, breach geometry data, and dam geometry data, into a unified table format for export; a file path selection box is provided in the user interface to allow users to specify the save location of the exported file. Users can also select the default path to facilitate quick export of results; when the file is successfully exported, the system displays a prompt message of successful export on the user interface and provides a file open option to facilitate users to quickly view the exported file.

[0026] Second, the data processing module includes the lake area-water level curve fitting module and the dam break process simulation module, which is responsible for simulating the dam break process. It calls the input parameters, fits and generates the barrier lake area-water level curve, simulates the barrier dam break process, saves the relevant data information, and transmits it to the data management module for easy calling.

[0027] Among them, the lake area-water level curve fitting module is mainly responsible for fitting and outputting the lake area-water level relationship curve, calling the lake area-water level data, using the fitting data tool, selecting the quadratic polynomial model to fit the relationship between water level and area, generating a mathematical expression of the water level-area relationship, and outputting the fitting data (such as water level-area curve data and fitting equation, etc.) to the dam break process simulation module.

[0028] The dam breach process simulation module is responsible for simulating the breach process at different times and obtaining relevant breach parameters based on time series through cyclic calculations, including breach flow, breach top and bottom width, breach bottom elevation, and breach slope angle.

[0029] 3. Data management module, including data verification, data transmission and storage, and data export functions, is responsible for the storage, verification, and export of all calculation results.

[0030] Data verification: After receiving the data transmitted by the user interface module and the data processing module, the received data is checked for validity. The main contents are: (1) Performing a numerical type check to ensure that the type of the input data is correct; (2) Performing a numerical range check to ensure that each data value is within a reasonable range and that the logic between related data is correct; (3) If the data is abnormal, the system will return an error message to the user interface to prompt the user to check the data.

[0031] Data transfer and storage: Receive data from the data processing module and store it in a structure, including water level-area relationship, breach flow change, breach width and elevation data, etc. The structure is stored in the structure for other modules to call.

[0032] Data export: When receiving an export instruction, this module will create a table corresponding to the instruction format, extract the data in the structure, assign them to independent worksheets by category, and save them to the specified directory.

[0033] like Figure 2 As shown, the present invention also provides a method for analyzing a barrier lake dam break system based on erosion prevention, and the specific steps are as follows: S1. Input relevant parameters through the user interface module and package them into a structure to ensure the integrity of each parameter, and then pass them to the data processing module.

[0034] S2. In the data processing module, input parameters are called to simulate the dam-breaking process of the barrier lake.

[0035] First, in the lake area-water level curve fitting module, according to the water balance principle, the change of reservoir water capacity can be expressed as: ; In the formula, For time; is the volume of water in the reservoir; is the surface area of ​​the reservoir; is the water level elevation; is the inflow; is the breach flow; is the spillway flow.

[0036] Through the capacity or area curve, the water level formula is as follows: ; In the formula, is the lake water level, is the reference height, , , is the fitting coefficient.

[0037] Then, the obtained fitting data is output to the dam break process simulation module to simulate the break process at different times. Through cyclic calculation, relevant break parameters based on time series are obtained.

[0038] Specifically, the operation process is as follows Figure 2 As shown, the following steps are included: S21, reading relevant input parameters in the user interface module, and obtaining corresponding water level-area relationship curve fitting data.

[0039] S22. Update the time step according to the time step length to determine whether the lake water level is greater than the bottom elevation of the breach.

[0040] If so, the flow rate of water passing through the breach within the time step is calculated using the broad-crowned weir flow formula, and then the water level change of the barrier lake within the time step is calculated based on the water balance equation, and the calculated flow rate and water level are updated and stored.

[0041] Otherwise, set the breach flow to 0, calculate the change in the water level of the barrier lake within the time step according to the water balance equation, and return to make a new judgment.

[0042] S23, call the flow and related input parameters, and calculate the corresponding dam break parameters as follows: First, the erosion model is used to calculate the breach erosion within a time step.

[0043] Since the dam burst water flow velocity is fast, there is an erosion-hindering effect, so the coefficient is introduced Construct an erosion model as follows: ; In the formula, is the erosion rate, in m / s; ; is the relative density; is the median particle size of sediment, in m; is the acceleration due to gravity; is a dimensionless number; It is a parameter that characterizes the state of sediment movement; It is a coefficient that reflects the influence of turbulence damping (turbulence collapse) in the near-bed area with extremely high sand concentration, the increase in kinematic viscosity, and the shear dilatancy behavior (significant increase in shear resistance) at the top of the sand bed.

[0044] in, , , , ; In the formula, is the density of sediment particles, in kg / m 3 ; is the water density in kg / m 3 ; is the collapse kinematic viscosity, in m 2 / s; is the dimensionless water shear force, is the critical Shields number, calculated as follows: , ; In the formula, is the shear stress, in N / m 2 ; is the critical stress.

[0045] ; In the formula, is the water flow velocity, in m / s; is Xie Cai coefficient, unit is m 0.5 / s, the calculation formula is as follows: ; In the formula, is the hydraulic radius, in m; It is the particle size of more than 90% of the sediment particles, in m.

[0046] In addition, when the burst water flows through the surface of the dam, the particles are placed in the burst water flow, and the equilibrium state of the particles under the action of buoyancy, water flow traction, friction between particles and their own gravity in the burst water flow is considered. Therefore, according to the equilibrium equation containing buoyancy, friction, water flow traction and gravity under the limit equilibrium condition, the critical starting shear stress of the particles is obtained. for: ; In the formula, is the porosity, is the particle size, is the inclination angle of the wetting line, It is the slope of the dam's back slope.

[0047] Then, the amount of cut at the bottom of the breach, the amount of lateral widening at the top and bottom of the breach are calculated by the erosion amount, and the corresponding breach elevation and width values ​​are calculated. The calculation formula is: ,in is the time step; and, in order to simulate the lateral changes of the breach, it is assumed that the lateral breach widening rate is the same as the vertical erosion rate.

[0048] S24. During the breach evolution, the bottom width and depth of the dam breach will increase with the erosion of the water flow. When the slope instability causes the instantaneous destruction of part of the breach slope, the top width of the breach will change instantly. Therefore, in the simulation of the breach evolution process, continuous erosion and the destruction caused by slope instability need to be considered.

[0049] In this embodiment, the breach slope stability is verified in each time step, wherein the breach slope stability analysis takes into account the force acting on the slope, the change in soil density, and the pore water pressure between soil particles. The calculation formula of the safety factor is as follows: ; in, ; ; In the formula, For stabilizing force, is a non-stabilizing force, , are the slopes of the breach slope before and after failure, is the slope height, is the weight of the failed block, is the volume ratio, is the friction angle, For soil cohesion.

[0050] When driving force Less than or equal to resistance When the driving force Greater than resistance When the breach slope is judged to be unstable, the breach slope angle becomes half of the sum of the rupture angle and the steepest stable slope angle.

[0051] S25, judging whether the bottom elevation of the breach is less than the critical elevation. If so, setting the bottom elevation of the breach equal to the critical elevation. Otherwise, using the calculated breach size of the barrier dam to update and store.

[0052] S26. Call up the bottom elevation of the breach and calculate the length and width of the back slope foot and the dam crest along the river based on the geometric relationship.

[0053] S27, judging whether the toe of the back slope is greater than or equal to the critical toe. If so, setting the toe of the back slope equal to the critical toe. If not, using the calculated toe of the back slope and the length and width of the dam crest along the river to update and store.

[0054] S28. Repeat steps S21 to S25 according to the set number of cycles until the predetermined cycle condition is reached, and transfer the stored results to the data management module for calling.

[0055] S3. The user interface module generates and visualizes the change curves of corresponding breach parameters according to the processing results of the data processing module, including: lake area-water level curve, breach flow curve, breach width change curve, breach elevation change curve, dam body geometry and breach geometry.

[0056] Therefore, the present invention adopts the above-mentioned dam-break analysis system and method based on hindering erosion, which can generate relatively accurate water level, breach flow, dam body and breach geometry change data, and through modular design, realize smooth parameter interaction and data visualization, and has good application prospects for disaster warning.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A barrier lake dam break analysis system based on erosion prevention, characterized in that: include: The user interface module includes parameter input, data transmission and reception, data visualization, and result export functions, allowing users to input parameters, start various functional modules, and visualize results; Data processing module, including lake area-water level curve fitting module and dam-break process simulation module. This data processing module is built based on the barrier lake dam-break model that hinders erosion effect and is responsible for simulating the dam-break process; The data management module is responsible for verifying, storing and exporting data, saving the data in a structure, and generating a file for the user to download when receiving an export instruction.

2. The barrier lake dam break analysis system based on erosion prevention according to claim 1 is characterized in that: The lake area-water level curve fitting module is used to call the lake area-water level data and use the fitting data tool to generate fitting data of the water level-area relationship.

3. The barrier lake dam break analysis system based on erosion prevention according to claim 1 is characterized in that: The dam break process simulation module is responsible for simulating the break process at different times and obtaining relevant break parameters based on time series through cyclic calculation.

4. The barrier lake dam break analysis system based on erosion prevention according to claim 1 is characterized in that: The barrier lake dam breach model based on the barrier erosion effect includes the establishment of an erosion model based on the barrier erosion effect, hydraulic analysis and breach evolution; Among them, the erosion model based on the barrier erosion effect is expressed as follows: ； In the formula, , is the erosion rate, is the relative density, is the median particle size of sediment, is the acceleration due to gravity, is a dimensionless number, It is a parameter that characterizes the state of sediment movement; A coefficient that reflects the damping of turbulence in the near-bed area where the sand concentration is extremely high, the increase in kinematic viscosity, and the shear dilatancy behavior at the top of the sand bed; In hydraulic analysis, an expression for water level is obtained from a capacity or area curve; In breach evolution, the breach evolution under continuous erosion is simulated, including the elevation change of the breach bottom and the lateral change of the breach.

5. The barrier lake dam break analysis system based on erosion prevention according to claim 4 is characterized in that: The expression is: ； In the formula, is the dimensionless water flow shear force.

6. The barrier lake dam break analysis system based on erosion prevention according to claim 1 is characterized in that: The data management module includes data verification, data transmission and storage, and data export functions; Among them, the data verification function is used to check the validity of the received data, including value type check, value range check and data anomaly check; Data transfer and storage functions are used to store received data into a structure for use by the data processing module and the user interface module; The data export function is used to receive export instructions, establish a table corresponding to the instruction format, extract the data in the structure, distribute them to independent worksheets by category, and save them to the specified directory.

7. A barrier lake dam break analysis method based on hindering erosion, using a barrier lake dam break analysis system based on hindering erosion as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Input relevant parameters through the user interface module, package them into a structure, and pass them to the data processing module; S2, the data processing module calls the input parameters, first uses the lake area-water level curve fitting module to obtain the fitting data of the water level-area relationship, and then outputs it to the dam break process simulation module to simulate the break process at different times, and obtains the relevant break parameters based on the time series through cyclic calculation; S3. The user interface module generates and visualizes the change curve of the corresponding collapse parameter according to the processing results of the data processing module.

8. The method for analyzing dam-break of barrier lake based on erosion prevention according to claim 7 is characterized in that: Step S2 comprises: S21, read the relevant input parameters in the user interface module, wherein the relevant input parameters include lake area-water level data, initial dam crest height, initial water level, residual dam height, initial breach depth and width, backwater slope angle, frontwater slope angle, critical backwater slope foot, inflow, particle bulk density, , , internal friction angle, cohesion, time step, number of cycles; S22, update the time step according to the time step length, and judge whether the lake water level is greater than the bottom elevation of the breach; if so, calculate the flow of water through the breach within the time step by using the broad-top weir flow formula, and calculate the change of the water level of the barrier lake within the time step according to the water balance equation, and use the calculated flow and water level to update and store; otherwise, set the breach flow to 0, calculate the change of the water level of the barrier lake within the time step according to the water balance equation, and return to make a new judgment; S23, calling the flow and related input parameters, using the erosion model to calculate the breach erosion amount within the time step, and calculating the amount of cut-off at the bottom of the breach and the lateral widening at the top and bottom of the breach through the erosion amount, and calculating the corresponding breach elevation and width values; S24, verify the stability of the breach slope in each time step. When the driving force is less than or equal to the resistance, the breach slope is judged to be stable; when the driving force is greater than the resistance, the breach slope is judged to be unstable, and the breach slope angle becomes half of the sum of the rupture angle and the steepest stable slope angle; S25, determining whether the elevation of the bottom of the breach is less than the critical elevation; if so, setting the elevation of the bottom of the breach equal to the critical elevation; otherwise, using the calculated breach size of the barrier dam to update and store; S26, call the bottom elevation of the breach, and calculate the length and width of the backwater slope foot and the dam crest along the river according to the geometric relationship; S27, judging whether the toe of the back slope is greater than or equal to the critical toe; if so, setting the toe of the back slope equal to the critical toe; otherwise, using the calculated toe of the back slope and the length and width of the dam crest along the river to update and store; S28. Repeat steps S21 to S25 according to the set number of cycles until the predetermined cycle conditions are reached, and transfer the stored results to the data management module.

9. The method for analyzing dam-break of barrier lake based on erosion prevention according to claim 8, characterized in that: When verifying the stability of the breach slope, the safety factor To determine the magnitude of driving force and resistance, the expression is as follows: ； in, ； ； In the formula, is the stabilizing force, i.e. resistance; It is a non-stabilizing force, i.e., a driving force; , are the slopes of the breach slope before and after failure, respectively; is the slope height, is the weight of the failed block, is the volume ratio, is the friction angle, For soil cohesion.

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