CN-121279176-B - Self-adaptive plain reservoir dam break simulation method for break position

CN121279176BCN 121279176 BCN121279176 BCN 121279176BCN-121279176-B

Abstract

The invention belongs to the technical field of hydraulic engineering, discloses a method for simulating dam break of a plain reservoir with self-adaptive break position, and aims to solve the problems of low modeling efficiency, large human error, poor model reusability and the like existing in the traditional method for simulating dam break aiming at uncertainty of the break position of the plain reservoir. According to the invention, the position of the breach is decoupled from the grid profile through a predefined self-adaptive boundary and automatic matching mechanism, the single scene switching is shortened to the minute level, the manual operation error is eliminated, the simulation of the breach at any position of the box dam is supported, the efficiency, the reliability and the flexibility of dam break risk analysis of a plain reservoir are greatly improved, and a powerful technical support is provided for flood control and disaster relief emergency decision.

Inventors

WANG WEIQI
ZHAO SONG
WANG RUI
YAN QINGHONG
ZHANG DAWEI

Assignees

中国水利水电科学研究院

Dates

Publication Date: 20260508
Application Date: 20250922

Claims (6)

1. A method for simulating dam break of plain reservoir with self-adaptive break position is characterized by comprising the following steps: Firstly, preliminarily judging a potential flooding range after dam break according to the elevation of the surrounding land surface of a plain reservoir to be researched, and determining a hydrodynamic model construction range; simultaneously acquiring vector boundary data of a plain reservoir along a dam body, a digital terrain model of a reservoir-free area in a hydrodynamic model construction range, land utilization type information and water level flow relations of outlet sections of various river channels in the hydrodynamic model construction range; Step two, taking the hydrodynamic model construction range determined in the step one as an outer boundary, taking a plain reservoir vector boundary as an inner boundary, and adopting triangular unstructured grids to mesh a modeling area, wherein a reservoir area in the inner boundary is subjected to cavity treatment and does not participate in mesh dissection; thirdly, adding a BC field describing boundary attributes for all grid edges, setting a default value as 0, defining the grid edge where an outer boundary is positioned as a fixed wall boundary, modifying the BC field value as 1, defining the grid edge where the section position of each river channel outlet is positioned as a downstream outlet boundary according to the distribution of the river channels in a modeling range, modifying the BC field value as 2, defining the grid edge where the inner boundary is positioned as a self-adaptive variable boundary, and modifying the BC field value as 9; Traversing all the grid edges with BC field values of 9 according to the index sequence of the grid edges, calculating the coordinates of the center point of each grid edge according to the coordinates of two end points of each grid edge, and establishing and storing an array structure containing the corresponding relation of grid edge index number, center point abscissa and center point ordinate; Step five, before the start of a crumple calculation scheme, obtaining crumple parameters, crumple position information and model calculation parameters; Step six, according to the position information of the crumple obtained in the step five, matching the self-adaptive variable boundary closest to the center of the crumple in the corresponding relation array established in the step four, modifying the grid edge type corresponding to the boundary into a dam break flow boundary, and adjusting the BC field value of the grid edge type from 9 to 4; Step seven, calculating a dam break flood flow process based on the dam break parameters obtained in the step five, and taking the flow process as a boundary condition of the dam break flow boundary in the step six; step eight, according to the model calculation parameters obtained in the step five, carrying out flood analysis calculation of the two-dimensional hydrodynamic model, and outputting a model calculation result; and step nine, after finishing the single-breach calculation scheme of the step five to the step eight, if the breach parameters or the breach position information are required to be modified, repeating the step five to the step eight to realize the breach position self-adaption function of the model, and if the breach parameters or the breach position information are not required to be modified, terminating the task and finishing the simulation of the dam break of the plain reservoir.
2. The method for simulating dam break of plain reservoir with self-adaptive breach position according to claim 1, wherein in the first step, a historical flood trace analysis method, a contour analysis method or a simplified hydraulic method is adopted to preliminarily judge the potential flooding range after dam break.
3. The method for simulating dam break of plain reservoir with self-adaptive breach position as claimed in claim 1, wherein in the second step, the elevation and roughness of the grid center are obtained by adopting the following formula interpolation calculation: Wherein Z P is the attribute value of the center P of the grid to be solved, namely the elevation or roughness value, Z A ,Z B ,Z C is the attribute value of three nodes A, B and C of the grid respectively, and S PBC ,S PAC ,S PAB ,S ABC is the area of a triangle formed by the subscript nodes.
4. The method for simulating dam break of plain reservoir with self-adaptive breach position according to claim 1, wherein in the fifth step, the breach parameters comprise initial breach bottom height, initial reservoir water level, initial breach width, final breach bottom height, breach maximum width and breach development history, the breach position information is a horizontal coordinate value and a longitudinal coordinate value of the breach center, and the model calculation parameters comprise calculation start and stop date, calculation step length and output step length.
5. The method for simulating dam break of plain reservoir with self-adaptive breach position according to claim 1, wherein in the eighth step, the control equation of the two-dimensional hydrodynamic model is a two-dimensional shallow water equation set, and a finite volume method or a finite difference method is adopted for solving.
6. The method for simulating dam break of plain reservoir with self-adaptive breach position as claimed in claim 1, wherein in the eighth step, the two-dimensional shallow water equation set is as follows: wherein h is water depth, u and v are flow velocity in x and y directions respectively, t is current time step, B (x, y) is bottom slope elevation, tau is friction term, subscripts bx and by are friction force component force of the friction term in x and y directions respectively, and g is gravity acceleration.

Description

Self-adaptive plain reservoir dam break simulation method for break position Technical Field The invention belongs to the technical field of hydraulic engineering, in particular to a plain reservoir dam break numerical simulation and flood control and disaster reduction technical direction, and particularly relates to a plain reservoir dam break simulation method with a self-adaptive breach position. Background The dam break of the reservoir is taken as a natural disaster type with very damaging property in the field of hydraulic engineering, and flood has the remarkable characteristics of high flow peak value, high evolution speed and wide influence range, and once destructive striking is often caused on downstream towns, farmlands and ecological systems, so that accurate and efficient dam break flood numerical simulation is a core technical support for flood control and disaster reduction decision-making, risk assessment and emergency plan making. The existing mature scheme is designed for reservoirs in mountain areas, the reservoirs are usually provided with definite main dam/auxiliary dam addresses due to topography constraint, and the breach positions are highly concentrated on specific dam segments, so that the traditional simulation method generally adopts a technical path of presetting fixed breach positions, namely spatial coordinates and attribute parameters of the breach boundaries are directly locked in a grid subdivision stage, flood evolution calculation is only needed to be carried out on the basis of fixed boundary conditions, technical logic is highly matched with the breach characteristics of reservoirs in mountain areas, and a good simulation effect can be achieved in mountain area scenes. However, the structural characteristics of the plain reservoir and the mountain reservoirs have essential differences, so that the conventional technical path is completely inapplicable, the plain reservoir adopts a construction mode of 'a surrounding dam ring', the surrounding dams are continuously distributed along the periphery of the reservoir and the length is usually several kilometers to tens kilometers, dam break risk points are not concentrated on specific dam segments, and the dam break risk points are possibly randomly generated at any position of the surrounding dams due to factors such as uneven dam mass, local seepage damage, extreme hydrologic loads (such as heavy rainfall and high water level continuous action) and the like, and the spatial distribution of a break has extremely strong uncertainty. This characteristic exposes three major core technical drawbacks in plain reservoir scenarios for traditional methods, and no effective solution has been proposed in the prior art: 1. Modeling efficiency is extremely low, and emergency requirements cannot be met. If a flood process at different crumple locations needs to be simulated, the conventional method needs to re-mesh each potential crumple—because the boundary properties of the conventional mesh are strongly bound to crumple locations, changing crumple locations means that the mesh topology needs to be readjusted to fit the new crumple boundary. The plain reservoir modeling range is wide, the topographic data is complex, the single grid subdivision needs to consume several hours to days, when a plurality of potential breach risks need to be evaluated, the workload is in linear superposition, and the decision requirement of 'hour-level' emergency simulation in dam break burst cannot be met completely; 2. The boundary setting is tedious and prone to human error. Every time the position of the crumple is replaced, the grid is not only required to be re-divided, but also the flow boundary sequence of the crumple boundary and the connection relation with the peripheral solid wall boundary are manually redefined. The manual operation is time-consuming, errors are easily introduced due to personnel operation differences (such as boundary coordinate positioning deviation and flow boundary sequence confusion), so that simulation results of different breach scenes lack consistency, and the reliability of risk assessment is affected; In the prior art, although some researches try to optimize the dam break simulation flow of the plain reservoir (such as simplifying mesh subdivision parameters and presetting a part of boundary templates), the core limit of strong binding of the position of a broken opening and the boundary of a mesh is not broken through, namely, the dam break simulation method can only simulate a few preset points on the box dam and can not cover any broken opening position, or the boundary attribute modification is supported, the local adjustment of the mesh is still needed, and the real self-adaption is not realized. Therefore, a plain reservoir dam break simulation technology capable of thoroughly getting rid of the binding relation between grid sectioning and the position of a break and realizing rapid adaptation of any break p