A two-dimensional flood simulation method, equipment and medium for continuous dam breach of cascade reservoirs

Abstract

This application discloses a method, device, and medium for simulating two-dimensional floods caused by continuous dam failures in cascade reservoirs. The method relates to the technical fields of hydrodynamic modeling and flood disaster simulation. The method includes: Based on data related to the cascade reservoirs, without considering the regulating and storage function of the interval reservoirs and the impact of continuous dam failures, comprehensively modeling the cascade reservoirs to obtain a comprehensive two-dimensional hydrodynamic model and a maximum inundation range; segmenting the cascade reservoirs step by step according to the number of reservoirs, and performing two-dimensional modeling on the reservoirs in each segment to obtain a segmented two-dimensional model; during the step-by-step simulation, based on the dam failure rules of the reservoirs in each segment, using the comprehensive two-dimensional hydrodynamic model or the segmented two-dimensional model to simulate and obtain inundation results for each segmented two-dimensional model; and finally, overlaying the maximum inundation range and inundation results to generate a cascade reservoir dam failure flood risk map. This application can improve the computational efficiency and accuracy of continuous dam failure simulation analysis for cascade reservoirs.

Description

Technical Field

[0001] The present application relates to the technical field of hydrodynamic modeling and flood disaster simulation, and in particular to a two-dimensional flood simulation method, equipment and medium for continuous dam break of cascade reservoirs. Background Art

[0002] The compilation and application of reservoir flood risk maps, as an indispensable non-engineering measure in the flood disaster prevention and control system, plays an important role in promoting the optimization and improvement of the basin flood control engineering system, the scientific management of floodplains, and the preventive pre-emptive measures of emergency measures.

[0003] Analyzing the inundation caused by the successive dam failures of cascade reservoirs and the resulting flooding is an essential component of the technical requirements for compiling flood risk maps. Currently, simplified one-dimensional hydrodynamic simulation methods, two-dimensional hydrodynamic simulation methods, and one- and two-dimensional coupled simulation methods are commonly used to simulate the successive dam failures of cascade reservoirs. The simplified one-dimensional hydrodynamic simulation method reflects the evolution of floods within the river channel but cannot accurately simulate the flow of floods outside the river channel. It is only applicable in mountainous areas and has limited applicability in plain areas. The two-dimensional hydrodynamic simulation method struggles to reflect changes in flood flow and water levels caused by the regulation and failure of downstream reservoirs, as well as changes in dam crest and bottom elevations and their impacts. The one- and two-dimensional coupled simulation method requires detailed cross-sectional data and reservoir area topography, and the modeling process is extremely complex, with high measurement costs and low computational efficiency. Therefore, improving the computational efficiency and accuracy of simulation analysis of successive dam failures in cascade reservoirs is a major challenge in compiling reservoir flood risk maps. Summary of the Invention

[0004] The purpose of this application is to provide a two-dimensional flood simulation method, equipment and medium for continuous dam break of cascade reservoirs, which can improve the computational efficiency and accuracy of simulation analysis of continuous dam break of cascade reservoirs.

[0005] To achieve the above objectives, this application provides the following solutions:

[0006] In a first aspect, the present application provides a two-dimensional flood simulation method for continuous dam failure of cascade reservoirs, comprising:

[0007] Without considering the regulation and storage function of interval reservoirs and the impact of continuous dam failure, the overall two-dimensional model of the cascade reservoirs is constructed based on the data related to the cascade reservoirs to obtain the overall two-dimensional hydrodynamic model.

[0008] obtaining a maximum flooding range based on the overall two-dimensional hydrodynamic model;

[0009] From upstream to downstream, the cascade reservoirs are segmented step by step according to the number of reservoirs, and the reservoirs in each segment are modeled in two dimensions to obtain a segmented two-dimensional model;

[0010] In the process of simulating the segmented 2D model step by step from upstream to downstream, based on the dam-breaking rules of the reservoir in each level, the segmented 2D model is used to simulate and obtain the inundation results of the segmented 2D model at each level;

[0011] Superimposing the maximum inundation range and the inundation results of each level of segmented two-dimensional models to obtain a final inundation result;

[0012] Generate a cascade reservoir dam breach flood risk map based on the final inundation results.

[0013] Optionally, obtaining a maximum flooding range based on the overall two-dimensional hydrodynamic model includes:

[0014] The overall two-dimensional hydrodynamic model is used to perform trial calculation simulation of flood evolution to obtain the maximum inundation range; the longitudinal calculation range of the maximum inundation range is used as the lower boundary, and the lateral calculation range of the maximum inundation range is used as the maximum inundation range of the flood along both sides of the river bank.

[0015] Optionally, a two-dimensional model is performed on the reservoir in each segment to obtain a segmented two-dimensional model, including:

[0016] According to the dam-break conditions, determine the dam-break location and dam-break flow process as the upper boundary conditions of the reservoir in each section;

[0017] Each segment is gridded with the dam site of the reservoir in each segment as the upper boundary, the main stream where the reservoir is located in each segment as the lower boundary, and the ridge lines on both sides of the downstream impact area of ​​each segment as the side boundaries.

[0018] Based on the grid generation results, the local terrain of each segment is meshed; the local terrain includes the river channel, the dam site of the downstream cascade reservoir, and the levee;

[0019] Based on the DEM data and land use data of each segment, the encrypted grid is interpolated to obtain the elevation and roughness of each grid to obtain a segmented two-dimensional model.

[0020] Optionally, in the process of simulating the segmented two-dimensional model step by step from upstream to downstream, based on the dam-breaking rule of the reservoir in each level, when the segmented two-dimensional model is selected for simulation, the process of obtaining the inundation results of the segmented two-dimensional model at each level includes:

[0021] From upstream to downstream, for each level of segmented two-dimensional model, the model parameters of the segmented two-dimensional model are set, and the upper boundary condition flow process and the lower boundary condition free outflow are imported to simulate the flood evolution and obtain the inundation results of each level of segmented two-dimensional model; the model parameters include the calculation step size and the initial water depth; the inundation results of each level of segmented two-dimensional model include the inundation range, the inundation depth of each grid, and the flood arrival duration.

[0022] Optionally, for each level of the segmented two-dimensional model, from upstream to downstream, set the model parameters of the segmented two-dimensional model, import the flow process of the upper boundary condition and the free outflow of the lower boundary condition, perform flood evolution simulation, and obtain the inundation results of each level of the segmented two-dimensional model, including:

[0023] The lower boundary condition of each level of the segmented two-dimensional model is set as the free outflow of the downstream reservoir, and the upper boundary condition is the superposition of the interval flood during the flood discharge or dam breach process of the upstream reservoir, simulating the flow process of the upstream dam breach flood evolving to the dam site of the downstream reservoir.

[0024] In the process of simulating the flow of upstream dam-break floods to the dam site of downstream reservoirs, flood control calculations are performed according to the downstream reservoir operation rules to determine the maximum water level;

[0025] Simulating a downstream reservoir flood control or dam breach process based on the maximum water level to obtain an initial inundation result;

[0026] According to the flood control or dam break process of the downstream reservoir, the dynamic process of the reservoir water level is simulated, the local elevation at the lower boundary dam site of each level of the segmented two-dimensional model is adjusted, and the downstream reservoir water level process is used as the lower boundary condition of this segmented two-dimensional model. The initial inundation result is updated to obtain the inundation result of each level of the segmented two-dimensional model.

[0027] Optionally, simulating a downstream reservoir flood control or dam breach process based on the maximum water level includes:

[0028] When the highest water level exceeds the reservoir verification flood level, it is considered that the upstream reservoir has broken the dam, leading to the continuous dam breaking of the downstream reservoir, and the downstream reservoir dam breaking simulation is performed;

[0029] When the highest water level does not exceed the verified flood level of the reservoir, it is deemed that the downstream reservoir takes over the dam burst flood of the upstream reservoir through its own regulation and storage, and a downstream reservoir flood regulation simulation is carried out.

[0030] Alternatively, during the simulation of flood control or dam failure at the downstream reservoir, the downstream reservoir discharges water through the spillway before reaching the maximum water level; after the downstream reservoir reaches the maximum water level, the downstream reservoir instantly fails due to the impact of the upstream flood; the formula for determining the dam failure peak flow is:

[0031] ;

[0032] Where, is the dam-break peak flow, is the dam crest width, is the width of the breach, is the acceleration due to gravity, The water depth in front of the dam before the dam burst;

[0033] After obtaining the dam-break peak flow, the dam-break flow process is determined according to the empirical curve method.

[0034] Optionally, according to the flood control or dam failure process of the downstream reservoir, the dynamic process of the reservoir water level is simulated, the local elevation at the dam site of the lower boundary of each level of the segmented two-dimensional model is adjusted, and the downstream reservoir water level process is used as the lower boundary condition of this segmented two-dimensional model to update the initial inundation result, including:

[0035] According to the emergency flood discharge and dam breach process of the downstream reservoir, the reservoir water level process and the final breach width and breach depth of the reservoir dam are determined. The local elevation at the lower boundary dam site in each level of the segmented two-dimensional model is reduced according to the breach depth, and the reduced local elevation is used as the elevation corresponding to the final dam breach. The downstream reservoir water level process is used as the lower boundary condition of each level of the segmented two-dimensional model to simulate and update the initial inundation result.

[0036] In a second aspect, the present application provides a computer device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above-mentioned method for simulating two-dimensional floods caused by continuous dam failure of cascade reservoirs.

[0037] In a third aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-mentioned method for simulating continuous dam break two-dimensional floods of cascade reservoirs.

[0038] According to the specific embodiments provided in this application, this application has the following technical effects:

[0039] The present application provides a two-dimensional flood simulation method, equipment and medium for continuous dam break of cascade reservoirs. By combining the segmented two-dimensional models of each level on the basis of the overall two-dimensional hydrodynamic model, the continuous dam break flood simulation of cascade reservoirs is carried out. This method can overcome the application defects of the traditional one-dimensional hydrodynamic simulation method in plain areas. The two-dimensional hydrodynamic simulation method is difficult to reflect the storage and regulation of downstream reservoirs and the impact of dam break. It overcomes the data limitations of the one- and two-dimensional coupled simulation method, accurately simulates the dynamic changes of boundary conditions caused by reservoir flood regulation and dam break, and thus solves the problems of poor applicability of simplified models in the existing technology, lack of reservoir continuous break effect and excessively high terrain data requirements of the coupled model, and improves the computational efficiency and accuracy of the simulation analysis of continuous dam break of cascade reservoirs. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 A schematic flow chart of a two-dimensional flood simulation method for continuous dam breaches of cascade reservoirs provided in one embodiment of the present application;

[0042] Figure 2 A schematic diagram of the flood flow process of reservoir A and reservoir B with a calibration frequency according to an embodiment of the present application;

[0043] Figure 3 An embodiment of the present application provides Figure 2 Schematic diagram of the corresponding dam-break flow process results of reservoirs A and B;

[0044] Figure 4 A schematic diagram showing the results of a flow calculation process using a segmented two-dimensional model from the dam site of reservoir A to the dam site of reservoir B provided in one embodiment of the present application;

[0045] Figure 5 A schematic diagram showing the results of a two-dimensional flow calculation model for the section from the dam site of Reservoir B to the dam site of Reservoir C and flood control calculation for the downstream reservoirs provided in one embodiment of the present application;

[0046] Figure 6 A schematic diagram of the results of calculating the maximum flooding depth by segmented modeling after a continuous collapse provided in one embodiment of the present application;

[0047] Figure 7 A schematic diagram of the structure of a computer device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0049] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0050] In an exemplary embodiment, the present application provides a two-dimensional flood simulation method for continuous dam failure of cascade reservoirs. The method is executed by a computer device, specifically a computer device such as a terminal or a server, or a terminal and a server. In the embodiment of the present application, the method is applied to a server as an example for explanation. Figure 1 As shown, the method includes the following steps 100 to 105.

[0051] Step 100: Without considering the storage and regulation function of the interval reservoirs and the impact of continuous dam breaks, based on the data related to the cascade reservoirs, an overall two-dimensional model of the cascade reservoirs is performed to obtain an overall two-dimensional hydrodynamic model.

[0052] Among them, the data related to cascade reservoirs include: reservoir water level-storage capacity relationship, reservoir dam characteristic data, flood discharge facility characteristic data, topographic data covering the reservoir area and downstream impact area, land use type data, etc.

[0053] Step 101: Obtain the maximum flooding range based on the overall two-dimensional hydrodynamic model. This step is to determine the preliminary longitudinal and lateral calculation ranges.

[0054] Step 102: From upstream to downstream, the cascade reservoirs are segmented step by step according to the number of reservoirs, and a two-dimensional model is performed on the reservoirs in each segment to obtain a segmented two-dimensional model.

[0055] The upper boundary of the segmented two-dimensional model is the upstream reservoir dam site, and the lower boundary is the downstream reservoir dam site. The solid wall boundary of the segmented two-dimensional model must be larger than the inundation range of the overall modeling in the interval, that is, the maximum inundation range.

[0056] Step 103: In the process of simulating the segmented two-dimensional model step by step from upstream to downstream, based on the dam-breaking rules of the reservoir in each level, the overall two-dimensional hydrodynamic model or the segmented two-dimensional model is used for simulation to obtain the inundation results of the segmented two-dimensional model at each level.

[0057] The inundation results of each level of segmented two-dimensional models include: inundation range, inundation depth of each grid, and flood arrival time.

[0058] In actual application, when the dam burst of the reservoir in the current level evolves to a flood level in the next level reservoir that is lower than the check flood level of the next level reservoir, the overall two-dimensional hydrodynamic model can be used to simulate the flood evolution process of the reservoir in the current level, and the segmented two-dimensional model can be used to simulate the flood evolution process of the next level reservoir.

[0059] Step 104: superimpose the maximum flooding range and the flooding results of each level of segmented two-dimensional models to obtain the final flooding result.

[0060] Step 105: Generate a cascade reservoir dam-break flood risk map based on the final inundation results.

[0061] By implementing the above steps 100 to 105, the present application can improve the computational efficiency and accuracy of the simulation analysis of continuous dam breaks of cascade reservoirs.

[0062] In another exemplary embodiment of the present application, the initial boundary range is determined through trial calculations. The longitudinal calculation range of the initial boundary range (i.e., the lower boundary) is the section where the dam break flood flow rate decays steadily. The lateral calculation range of the initial boundary range (i.e., the solid wall boundary) is the maximum flooding position along both sides of the riverbank. Based on this, the implementation process of step 101 can be described as follows:

[0063] A two-dimensional hydrodynamic model was used to simulate flood evolution and determine the maximum inundation range. The longitudinal calculation range of the maximum inundation range was used as the lower boundary, and the lateral calculation range of the maximum inundation range was used as the maximum inundation range along both sides of the riverbank.

[0064] In another exemplary embodiment of the present application, in step 102, the process of performing two-dimensional modeling on the reservoir in each segment and obtaining the segmented two-dimensional model can be replaced by the following steps 200 to 203.

[0065] Step 200: According to the dam-break condition, determine the dam-break location and dam-break flow process as the upper boundary conditions of the reservoir in each segment.

[0066] Step 201: Using the dam site of the reservoir in each segment as the upper boundary, the main stream (i.e., the first-level main stream) where the reservoir is located in each segment as the lower boundary, and the ridge lines on both sides of the reservoir downstream impact area (i.e., the mountain ridge lines on both sides) in each segment as the lateral boundaries, model software such as the Surface Water Modeling System (SMS) and the MIKE Models (MIKE) are used to mesh each segment.

[0067] Step 202: Based on the mesh generation results, the local terrain of each segment is meshed. The local terrain includes the river channel, the dam site of the downstream cascade reservoir, and the embankment.

[0068] Step 203: Based on the Digital Elevation Model (DEM) data and land use data of each segment, the encrypted grid is interpolated to obtain the elevation and roughness of each grid, thereby obtaining a segmented two-dimensional model.

[0069] In another exemplary embodiment of the present application, to improve the accuracy of flooding simulation results, in step 103, for each level of the segmented 2D model, from upstream to downstream, a hydrodynamic model, such as MIKE or the Hydrological Engineering Center's River Analysis System (HEC-RAS), is used to set model parameters for the segmented 2D model. The upper boundary condition flow process and the lower boundary condition free outflow are then imported to simulate flood evolution and obtain flooding results for each level of the segmented 2D model. Model parameters include the calculation step size and initial water depth.

[0070] Based on the above description, the process of obtaining the submergence results of each level of the segmented 2D model may include:

[0071] Step 1. For any first-level segmented two-dimensional model, during the first simulation, set the lower boundary condition of this segmented two-dimensional model to the free outflow of the downstream reservoir, and the upper boundary condition to the upstream reservoir flood discharge or dam break process superimposed on the interval flood, and simulate the flow process of the upstream dam break flood evolving to the dam site of the downstream reservoir.

[0072] Step 2. When simulating the flow of the upstream dam-break flood to the downstream reservoir site, perform flood control calculations according to the downstream reservoir scheduling rules to determine the maximum water level to determine whether continuous dam break occurs.

[0073] Among them, when the highest water level exceeds the reservoir's verified flood level, it is regarded as the upstream reservoir's dam breach leading to the downstream reservoir's continuous dam breach, and a downstream reservoir dam breach simulation is performed.

[0074] When the highest water level does not exceed the verified flood level of the reservoir, it is deemed that the downstream reservoir takes over the dam burst flood of the upstream reservoir through its own regulation and storage, and a downstream reservoir flood regulation simulation is carried out.

[0075] Step 3. Simulate the flood control or dam break process of the downstream reservoir based on the highest water level to obtain the initial inundation result.

[0076] Step 4. Based on the flood control or dam break process of the downstream reservoir, simulate the dynamic process of the reservoir water level, adjust the local elevation at the dam site at the lower boundary of this level of segmented two-dimensional model, and use the downstream reservoir water level process as the lower boundary condition of this level of segmented two-dimensional model to update the initial inundation result and obtain the inundation result of this level of segmented two-dimensional model.

[0077] The above steps 1 to 4 are executed cyclically until the flood inundation simulation calculation of the lowest level segmented two-dimensional model is completed, and the inundation results of all segmented two-dimensional models are obtained.

[0078] In another exemplary embodiment of the present application, to determine the dam-break flow process, during a simulation of flood control or dam-break at a downstream reservoir, the downstream reservoir's water storage capacity, before reaching its maximum water level, is subjected to emergency flood discharge through a spillway. After the downstream reservoir's water storage capacity reaches its maximum water level, the downstream reservoir is instantly breached by the impact of the upstream flood.

[0079] The formula for determining the dam-break peak flow is:

[0080] .

[0081] Where, is the dam-break peak flow, is the dam crest width, is the width of the breach, is the acceleration due to gravity, It is the water depth in front of the dam before the dam burst.

[0082] After obtaining the dam break peak flow, the dam break flow process can be determined according to the empirical curve method.

[0083] In another exemplary embodiment of the present application, in order to further improve the accuracy of the submergence result, in actual application, the submergence result is adjusted by adjusting the elevation information. Based on this, the implementation process of the above step 3 can be described as follows:

[0084] Based on the emergency flood discharge and dam breach process of the downstream reservoir, the reservoir water level process and the final breach width and depth of the reservoir dam are determined. The local elevation at the lower boundary dam site in each level of the segmented two-dimensional model is reduced (i.e., lowered) according to the breach depth, and the reduced local elevation is used as the elevation corresponding to the final dam breach. The downstream reservoir water level process is used as the lower boundary condition of each level of the segmented two-dimensional model to simulate and update the initial inundation results.

[0085] Based on the description of the above embodiments, the present application adopts a full two-dimensional hydrodynamic model (i.e., an overall two-dimensional hydrodynamic model and segmented two-dimensional models at each level), which breaks through the application defects of traditional one-dimensional hydrodynamic simulation methods in plain areas. The two-dimensional hydrodynamic simulation method is difficult to reflect the regulation and storage of downstream reservoirs and the impact of dam breaches. It overcomes the data limitations of the one- and two-dimensional coupled simulation method, accurately simulates the dynamic changes in boundary conditions caused by reservoir flood regulation and dam breaches, and thus solves the problems of poor applicability of simplified models in the existing technology, lack of reservoir burst effects, and excessively high terrain data requirements for coupled models.

[0086] In another exemplary embodiment of the present application, taking a cascade reservoir group in a certain province in China as an example, the implementation process and effect of the two-dimensional flood simulation method for continuous dam break of cascade reservoirs provided above in the present application are explained.

[0087] The cascade reservoir group consists of three reservoirs connected in series. Some engineering characteristics of these three reservoirs are shown in Table 1.

[0088] Table 1 Reservoir project characteristics report

[0089]

[0090] Based on the above information, the method provided in this application was used to simulate continuous dam-break floods in a cascade reservoir group in a certain province in China, including:

[0091] S1. Without considering the regulation and storage function of interval reservoirs and the impact of continuous dam failure, a full two-dimensional overall modeling of a cascade reservoir group in a certain province in China was carried out to obtain an overall two-dimensional hydrodynamic model. The longitudinal and lateral calculation ranges were preliminarily determined based on the inundation results.

[0092] For example, the calculation condition is that reservoir A and reservoir B have floods with the corresponding check frequency flood dam breach situation. The corresponding inflow flood process and dam breach flow process of reservoirs A and B are as follows: Figure 2 and Figure 3 shown.

[0093] For the simulation of Reservoir A's dam failure, the dam site of Reservoir A was used as the upper boundary, disregarding the regulation and storage of downstream reservoirs. A hydrodynamic model was used to construct a two-dimensional model of the cascade reservoir complex. For the simulation of Reservoir B's dam failure, the dam site of Reservoir B was used as the upper boundary, disregarding the regulation and storage of downstream reservoirs. A two-dimensional model of the cascade reservoir complex was constructed. Preliminary calculations showed that the inundation range would affect the downstream urban area, and the lower boundary of the cascade reservoirs was determined to be the point where the tributaries merge into the next-level mainstream river.

[0094] S2. Build a two-dimensional model in sections, one by one, according to the number of reservoirs. The upper boundary of the sectioned two-dimensional model is the upstream reservoir dam site, and the lower boundary is the downstream reservoir dam site. The solid wall boundary must be larger than the inundation range of the overall modeling interval.

[0095] A cascade reservoir group in a certain province in China includes three reservoirs, with the dam sites of Reservoir B and Reservoir C as the boundaries. Three segmented two-dimensional models were established: Reservoir A Dam Site-Reservoir B Dam Site, Reservoir B Dam Site-Reservoir C Dam Site, and Reservoir C-next-level mainstream river estuary. The solid wall boundaries are the ridge lines on both sides of the river.

[0096] S3: Simulate step-by-step from upstream to downstream. For any segmented 2D model, set the lower boundary condition to free outflow from the downstream reservoir during the first simulation. Simulate the flow process of the upstream reservoir dam break flood to the downstream dam site. Calculate the maximum water level based on the downstream reservoir flood control rules to determine whether a continuous dam break has occurred.

[0097] Flood control calculations are performed based on downstream reservoir operation rules to calculate the maximum reservoir water level. If this maximum reservoir water level exceeds the reservoir's verified flood level, it is determined that the upstream reservoir breach has caused a series of downstream reservoir breaches. Otherwise, it is considered that the downstream reservoir can absorb the upstream reservoir breach floodwater through its own regulation and storage.

[0098] Based on the above description, in this example, interval inflow is not considered. For the dam break of Reservoir A, the lower boundary condition of the segmented 2D model between Dam Site A and Dam Site B is assumed to be free outflow, and the hydrodynamic model is used to simulate the evolution of the dam break flood. For the dam break of Reservoir B, the lower boundary condition of the segmented 2D model between Dam Site B and Dam Site C is assumed to be free outflow, and the hydrodynamic model is used to simulate the evolution of the dam break flood.

[0099] According to the flood control rules of the downstream reservoirs, the dam failure of Reservoir A evolves to the flood level of Reservoir B (peak flow 3371 m 3 / s) is lower than the verified flood level of Reservoir B (peak flow 6486 m 3 / s), such as Figure 4 As shown in Figure 2, it does not lead to continuous dam failure of Reservoir B. The dam failure flood of Reservoir B evolves to the flood level of Reservoir C (peak flow 8876 m 3 / s) is higher than the verified flood level of reservoir C (peak flow 6130 m 3 / s), such as Figure 5 As shown, it will cause continuous dam collapse of downstream reservoir C.

[0100] Therefore, the dam breach of Reservoir A can be directly modeled using a holistic 2D model (i.e., constructing a 2D hydrodynamic model). However, the dam breach of Reservoir B requires considering the impact of the continuous dam breach of Reservoir C downstream, requiring segmented modeling (i.e., 2D modeling of each reservoir in each segment). Based on this, the method provided in this application can employ different modeling approaches to simulate the dam breach process for different reservoir classifications.

[0101] S4. According to the flood control or dam break process of the downstream reservoir, the dynamic process of the reservoir water level is confirmed, and the local elevation at the dam site at the lower boundary of the segmented two-dimensional model is adjusted. The downstream reservoir water level process is used as the lower boundary condition of the segmented two-dimensional model to update the flood inundation simulation results of the segmented two-dimensional model.

[0102] In this embodiment, the flow process and reservoir water level process of the downstream reservoir C caused by the dam failure of reservoir B are as follows: Figure 5 As shown, the dam break is instantaneous and the peak flow of the dam break is This was calculated using the modified broad-crested weir formula given above. Correspondingly, the breach width was calculated to be 30m and the breach depth to be 13.12m. For the segmented 2D model of Reservoir B Dam Site - Reservoir C Dam Site, the elevation of the dam body near the spillway at Reservoir C Dam Site at the lower boundary was lowered to the dam bottom elevation (i.e., 89.4m). Using the reservoir water level process at Reservoir C as the lower boundary condition, the segmented 2D model was updated and the new inundation results were calculated.

[0103] S5. Execute steps S3 and S4 in a loop until the flood analysis of the lowest-level reservoir is completed.

[0104] In this embodiment, the flood discharge of reservoir C (such as Figure 5 As shown in the figure, the upper boundary condition of the segmented two-dimensional model of reservoir C and the next-level mainstream estuary is used, and the lower boundary condition is that the flood flows freely along the next-level mainstream estuary, completing the flood analysis simulation of the continuous dam breach of reservoir C caused by the dam breach of reservoir B.

[0105] S6. Superimpose the maximum inundation range and the inundation results of the segmented two-dimensional models at each level to generate (or draw) a cascade reservoir dam break flood risk map.

[0106] In this example, the dam breach of reservoir A did not lead to a series of dam breaches in the downstream reservoirs, so the overall 2D modeling can be used for simulation. The dam breach of reservoir B led to a series of dam breaches in the downstream reservoir C. By superimposing the flooding results obtained from the two segmented 2D model simulations of reservoir B dam site-reservoir C dam site in step S4 and reservoir C-next-level mainstream estuary in step S5, a flood risk map for the case of a series of dam breaches downstream caused by the dam breach of reservoir B is obtained. The maximum flooding depth result is as follows: Figure 6 shown.

[0107] In another exemplary embodiment of the present application, the simulated flooding results for the dam breach of Reservoir B, calculated using a one- and two-dimensional coupled simulation method, are compared with the method provided in this application. As shown in Table 2, the difference in flooded area calculated by the two methods is within 5%, and the maximum flooded water depth is approximately 40 m. This indicates that the method provided in this application is equivalent to the traditional method (i.e., the one- and two-dimensional coupled simulation method) in terms of flood risk mapping. However, the one- and two-dimensional coupled simulation method requires additional data such as river section extraction and one- and two-dimensional interface coupling based on the DEM, which is time-consuming and labor-intensive. The method provided in this application, through full two-dimensional modeling, can avoid the aforementioned data preprocessing step and significantly improve computational efficiency while ensuring the accuracy of flood analysis calculations.

[0108] Table 2 Comparison of flooding results of different cascade reservoir dam break simulation methods

[0109]

[0110] Furthermore, this application adopts a mechanism of segmented simulation and dynamic adjustment of boundary conditions, which can explicitly depict the chain effect of flood control and dam breach of cascade reservoirs, thereby effectively overcoming the defects of the existing technology such as poor applicability of simplified models, lack of continuous breach effects, and excessively high requirements for terrain data. It is particularly suitable for emergency simulation scenarios of continuous dam breach of cascade reservoirs.

[0111] In an exemplary embodiment, a computer device is provided. The computer device may be a server or a terminal. The internal structure diagram thereof may be as follows: Figure 7 As shown. The computer device includes a processor, a memory, an input / output interface (I / O) and a communication interface. The processor, memory and input / output interface are connected via a system bus, and the communication interface is connected to the system bus via the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and computer program in the non-volatile storage medium. The database of the computer device is used to store two-dimensional flood simulation data of continuous dam break of cascade reservoirs. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal via a network connection. When the computer program is executed by the processor, a two-dimensional flood simulation method of continuous dam break of cascade reservoirs is implemented.

[0112] Those skilled in the art will understand that Figure 7 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0113] In an exemplary embodiment, a computer device is provided, including a memory and a processor. The memory stores a computer program, and the processor implements the steps in the above method embodiments when executing the computer program.

[0114] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0115] In an exemplary embodiment, a computer program product may also be provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0116] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0117] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the above-mentioned embodiments. In particular, any reference to memory, database, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (RRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0118] The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processors involved in the various embodiments provided herein may include, but are not limited to, general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic units, data processing logic units based on quantum computing, and the like.

[0119] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0120] This document uses specific examples to illustrate the principles and implementation methods of this application. The description of the above examples is only intended to help understand the method and core concept of this application. At the same time, for those skilled in the art, based on the concept of this application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A two-dimensional flood simulation method for continuous dam failure of cascade reservoirs, characterized by: include: Without considering the regulation and storage function of interval reservoirs and the impact of continuous dam failure, the overall two-dimensional model of the cascade reservoirs is constructed based on the data related to the cascade reservoirs to obtain the overall two-dimensional hydrodynamic model. obtaining a maximum flooding range based on the overall two-dimensional hydrodynamic model; From upstream to downstream, the cascade reservoirs are segmented step by step according to the number of reservoirs, and the reservoirs in each segment are modeled in two dimensions to obtain a segmented two-dimensional model; In the process of simulating the segmented two-dimensional model step by step from upstream to downstream, based on the dam-breaking rules of the reservoir in each level, the overall two-dimensional hydrodynamic model or the segmented two-dimensional model is used for simulation to obtain the inundation results of the segmented two-dimensional model at each level. Among them, from upstream to downstream, for each level of the segmented two-dimensional model, the river analysis system of MIKE and the Hydrological Engineering Center is used to set the model parameters of the segmented two-dimensional model, and the upper boundary condition flow process and the lower boundary condition free outflow are imported to simulate the flood evolution and obtain the inundation results of the segmented two-dimensional model at each level. The model parameters include the calculation step size and the initial water depth. The inundation results of each level of the segmented two-dimensional model include the inundation range, the inundation depth of each grid, and the flood arrival duration. Superimposing the maximum inundation range and the inundation results of each level of segmented two-dimensional models to obtain a final inundation result; Generate cascade reservoir dam-break flood risk maps based on the final inundation results; The reservoir in each segment is modeled in two dimensions to obtain a segmented two-dimensional model, including: According to the dam-break conditions, determine the dam-break location and dam-break flow process as the upper boundary conditions of the reservoir in each section; The dam site of each segment is used as the upper boundary, the main stream of each segment is used as the lower boundary, and the ridge lines on both sides of the downstream impact area of ​​each segment are used as the lateral boundaries. The surface water model software and the Meek model software are used to mesh each segment. Based on the grid generation results, the local terrain of each segment is meshed; the local terrain includes the river channel, the dam site of the downstream cascade reservoir, and the levee; Based on the DEM data and land use data of each segment, the encrypted grid is interpolated to obtain the elevation and roughness of each grid to obtain a segmented two-dimensional model; The process of obtaining the flooding results of each level of the segmented two-dimensional model includes: Step 1. For any first-level segmented 2D model, during the first simulation, set the lower boundary condition of this segmented 2D model to free outflow from the downstream reservoir and the upper boundary condition to the upstream reservoir flood discharge or dam break process superimposed on the interval flood. Simulate the flow process of the upstream dam break flood evolving to the downstream reservoir dam site. Step 2. During the simulated flow process of the upstream dam-break flood evolving to the downstream reservoir site, flood control calculations are performed according to the downstream reservoir operation rules to determine the maximum water level to determine whether a continuous dam break has occurred. When the highest water level exceeds the reservoir check flood level, it is considered that the upstream reservoir has broken, leading to the continuous dam breaking of the downstream reservoir, and the downstream reservoir dam breaking simulation is performed; When the highest water level does not exceed the verified flood level of the reservoir, it is considered that the downstream reservoir, through its own regulation and storage, takes over the dam burst flood of the upstream reservoir, and the downstream reservoir flood regulation simulation is carried out; Step 3. Simulate the flood control or dam failure process of the downstream reservoir based on the highest water level to obtain the initial inundation result; Step 4. Based on the flood control or dam failure process of the downstream reservoir, simulate the dynamic process of the reservoir water level and adjust the local elevation at the dam site at the lower boundary of this stage of the segmented 2D model. Use the downstream reservoir water level process as the lower boundary condition of this segmented 2D model, update the initial inundation result, and obtain the inundation result of this stage of the segmented 2D model. The above steps 1 to 4 are executed cyclically until the flood inundation simulation calculation of the lowest level segmented two-dimensional model is completed, and the inundation results of all segmented two-dimensional models are obtained.

2. The two-dimensional flood simulation method for continuous dam break of cascade reservoirs according to claim 1 is characterized in that: The maximum flooding range is obtained based on the overall two-dimensional hydrodynamic model, including: The overall two-dimensional hydrodynamic model is used to perform trial calculation simulation of flood evolution to obtain the maximum inundation range; the longitudinal calculation range of the maximum inundation range is used as the lower boundary, and the lateral calculation range of the maximum inundation range is used as the maximum inundation range of the flood along both sides of the river bank.

3. The two-dimensional flood simulation method for continuous dam failure of cascade reservoirs according to claim 1 is characterized in that: Simulating the flood control or dam breach process of the downstream reservoir based on the maximum water level includes: When the highest water level exceeds the reservoir verification flood level, it is considered that the upstream reservoir has broken the dam, leading to the continuous dam breaking of the downstream reservoir, and the downstream reservoir dam breaking simulation is performed; When the highest water level does not exceed the verified flood level of the reservoir, it is deemed that the downstream reservoir takes over the dam burst flood of the upstream reservoir through its own regulation and storage, and a downstream reservoir flood regulation simulation is carried out.

4. The two-dimensional flood simulation method for continuous dam break of cascade reservoirs according to claim 1 is characterized in that: During the simulation of flood control or dam failure in the downstream reservoir, the water storage capacity of the downstream reservoir is discharged through the spillway before reaching the maximum water level; after the water storage capacity of the downstream reservoir reaches the maximum water level, the downstream reservoir is instantly breached due to the impact of the upstream flood. The formula for determining the dam failure peak flow is: ； Where, is the dam-break peak flow, is the dam crest width, is the width of the breach, is the acceleration due to gravity, The water depth in front of the dam before the dam burst; After obtaining the dam-break peak flow, the dam-break flow process is determined according to the empirical curve method.

5. The two-dimensional flood simulation method for continuous dam break of cascade reservoirs according to claim 1 is characterized in that: Based on the flood control or dam failure process of the downstream reservoir, the dynamic process of the reservoir water level is simulated, the local elevation at the dam site at the lower boundary of each stage of the segmented two-dimensional model is adjusted, and the downstream reservoir water level process is used as the lower boundary condition of this segmented two-dimensional model to update the initial inundation results, including: According to the emergency flood discharge and dam breach process of the downstream reservoir, the reservoir water level process and the final breach width and breach depth of the reservoir dam are determined. The local elevation at the lower boundary dam site in each level of the segmented two-dimensional model is reduced according to the breach depth, and the reduced local elevation is used as the elevation corresponding to the final dam breach. The downstream reservoir water level process is used as the lower boundary condition of each level of the segmented two-dimensional model to simulate and update the initial inundation result.

6. A computer device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the two-dimensional flood simulation method for continuous dam break of cascade reservoirs according to any one of claims 1 to 5.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for simulating two-dimensional floods caused by continuous dam failure of cascade reservoirs according to any one of claims 1 to 5 is realized.

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