CN-116933539-B - Cascade hydropower junction group dam continuous-bursting risk analysis method and system

CN116933539BCN 116933539 BCN116933539 BCN 116933539BCN-116933539-B

Abstract

The invention discloses a cascade hydroelectric junction group dam continuous-bursting risk analysis method and system. The analysis method comprises the steps of constructing a dam continuous-bursting physical model of the cascade hydroelectric junction group and a dam feeding flow calculation and dam feeding occurrence judgment model of the cascade hydroelectric junction group, and calculating and determining whether each dam is broken or overturned and the flood evolution situation after the break or overtravel occurs according to data such as dam body materials, reservoir capacity, dam height and dam top elevation of each dam in the hydroelectric junction group on the basis of the models. The method provided by the invention has the advantages that the application range is wide, excessive basic data do not need to be collected, the calculation efficiency and accuracy are high, and the continuous-bursting risk prevention and control capability of the cascade hydropower junction group is obviously improved.

Inventors

ZHOU JINJUN
Kong Zichen
LIU JIAHONG
WANG HAO
Song Tianxu
YU YINGDONG

Assignees

北京工业大学
中国水利水电科学研究院

Dates

Publication Date: 20260512
Application Date: 20230725

Claims (8)

1. A cascade hydroelectric junction group dam continuous collapse risk analysis method is characterized by comprising the following steps: s1, constructing a dam continuous-bursting physical model of a step hydroelectric junction group, wherein continuous bursting comprises continuous dam-breaking and/or overtopping; s2, constructing a dam-break flood flow calculation model based on the dam continuous-break physical model, and obtaining the flow of flood which is evolved to the next-stage dam after the dam of any-stage dam except the last-stage dam breaks or overturns according to the dam-break flood flow calculation model; S3, constructing a dam break occurrence condition analysis model based on the dam continuous break physical model, and obtaining the conditions of dam break or roof break of any one of the stages of dams except the final stage of dam, whether the next stage of dam breaks or roof break, dam break flow or barrage flow generated after the dam break or roof break occurs and the conditions of dam break and roof break; S4, obtaining physical parameters of each dam in the cascade hydroelectric junction group to be subjected to continuous collapse risk analysis, and determining whether each dam is collapsed or overturned and the flood evolution condition after the collapse or overtravel occurs through the dam continuous collapse physical model, the dam collapse flood flow rate measuring model and the dam collapse occurrence condition analyzing model; Wherein, the dam burst physical model is constructed as follows: The cascade hydroelectric junction group comprises n dams which are connected in series from upstream to downstream, namely a first-stage dam, a second-stage dam and an n-th-stage dam, wherein after the dam of any stage except the last-stage dam breaks or overtakes, the dam break or overtakes process stops when the water level is lower than the dead water level, then dam break or overtakes generate dam break flood which evolves to a subsequent-stage dam, when the dam break flood reaches the subsequent-stage dam, the water quantity of the subsequent-stage dam is the difference of the water quantity of the upstream water supply and the self water discharge quantity, if the water quantity of the subsequent-stage dam exceeds the dam top of the dam, the dam breaks or overtakes, and then the water quantity of the subsequent-stage dam is the water quantity of the upstream water supply plus the self water quantity minus the self water discharge quantity and the self water discharge quantity, and the dam break or overtakes process stops after the water level of the subsequent-stage dam drops to the dead water level; the dam break flood flow calculation model is constructed as follows: ; Wherein, the The flow of flood reaching the next dam is the maximum flow at x distance from the dam site of the dam where dam break or flood roof occurs; The dam break flow of the dam with dam break or the dam flow of the dam with flood top is the maximum flow at the dam site of the dam with dam break or the dam with flood top, w is the total flood amount, and is the difference value between the maximum reservoir capacity and the dead reservoir capacity, m3; n represents the coefficient of Manning roughness, x represents the distance between the dam where dam break or overtopping occurs and the dam of the subsequent stage; R represents the following parameters: ; ; Wherein A, m is a river bed section coefficient and an index, and m=1 when the river section shape is set to be rectangular.
2. The method of analysis according to claim 1, wherein the self-draining amount includes the power generation amount of the dam and the flood discharge amount thereof.
3. The analysis method according to claim 1, wherein the constructing of the dam break occurrence analysis model includes: s31, setting the time step to be 10S, and obtaining a reservoir capacity calculation model before dam break or overtopping of a next-stage dam, wherein the reservoir capacity calculation model is as follows: ; Wherein, the Representing the storage capacity before dam break or overtopping of the next-stage dam, Representing the original storage capacity of the dam, Expressed as upstream incoming water flow rate i.e. the flow rate of flood reaching the next-stage dam according to the evolution obtained in S2, Representing the self-draining flow of the dam; s32, obtaining the dam break or the water level change condition of the dam before overtopping according to the calculated reservoir capacity of the dam at the later stage before dam break or overtopping and the water level reservoir capacity curve of the dam at the later stage; S33, analyzing the dam break or flood peak condition of the next-stage dam according to the water level change condition before dam break or flood peak to obtain the conditions of dam break flow generated after dam break or flood peak and dam break flow generated after flood peak of the next-stage dam; s34, setting the time step to be 10S, and obtaining the reservoir capacity of the dam of the subsequent stage after dam break or overtopping according to the analysis result of the dam break or overtopping condition of the dam of the subsequent stage, wherein the reservoir capacity is as follows: ; Wherein, the Representing the storage capacity of the dam of the next level after dam break or overtopping; representing the dam break flow or the slice flow obtained according to S33; s35, obtaining the water level change condition of the dam after dam break or overtopping according to the reservoir capacity of the dam after dam break or overtopping of the next-stage dam and the water level reservoir capacity curve of the dam; S36, determining the dam break or top break progress condition of the dam according to the change condition of the water level after the dam break or top break, wherein the dam break or top break progress condition is determined to stop when the water level after the dam break or top break of the dam falls to the dead water level.
4. The method according to claim 3, wherein S33 comprises: (1) Determining whether the highest water level of the dam before dam break or top break exceeds the dam top elevation according to the water level change condition before dam break or top break, if not, judging that the dam is not broken, and all downstream levels of dams are not broken, otherwise, judging that the dam is broken or top break; (2) Judging whether dam break or overtopping occurs according to the dam type of the dam, calculating dam break flow if dam break occurs, and calculating dam flow if overtopping occurs.
5. The analysis method according to claim 4, wherein the dam type includes a earth-rock dam and a concrete dam, the dam is broken when the dam type is an earth-rock dam, and the flood peak occurs when the dam type is a concrete dam.
6. The method of claim 5, wherein the dam break flow is obtained by the following calculation model: , Wherein, the The dam break flow is the dam break flow; taking 8/27 as a flow parameter; The width of the river valley of the dam site is the width of the river valley of the dam site; g is the gravitational acceleration; Upstream water depth before dam break occurs for the dam.
7. The analysis method according to claim 5, wherein the slice flow is obtained by the following calculation model: If it is <0.67, The slice is a thin wall slice, the slice flow ; If 0.67< <2.5, The slice is a practical slice, the slice flow ; If 2.5< <10, Then the weir flow is a broadtop weir flow, the flow of the weir flow ; Wherein, the Representing the thickness of the slice roof, C is the influence coefficient of the upstream weir surface slope, when the upstream is vertical, the value of c is 1.0, and the calculation can be carried out assuming that the overflow is Cheng Zhongshang You Qianzhi; for measuring the shrinkage factor; the gravity acceleration is represented by the submerged coefficient, b is represented by the weir width, and g.
8. The cascade hydroelectric junction group dam continuous collapse risk analysis system for realizing the analysis method according to any one of claims 1-7 is characterized by comprising a hydroelectric junction group dam group database module for acquiring and storing dam type, dam height and dam top elevation data, a dam collapse calculation module for constructing and storing a dam collapse flood flow rate model and a dam collapse occurrence analysis model, and a dam collapse result analysis module for acquiring analysis results according to the data and the models.

Description

Cascade hydropower junction group dam continuous-bursting risk analysis method and system Technical Field The invention relates to the technical field of a method for analyzing the continuous burst risk of a hydropower junction group. Background In order to better develop the water conservancy and hydropower engineering, most reservoirs are designed as cascade reservoirs, cascade hydropower junction groups are a plurality of reservoir dams which are continuously developed and built on a planned river reach and distributed in a cascade manner from upstream to downstream, and are engineering groups formed by a plurality of hydropower engineering. With the continuous increase of the scale and the number of the step hydropower junction groups, the risk of accident is more serious, and once the step hydropower junction groups are collapsed, huge losses are caused in the aspects of downstream life, economy and the like, so that the step hydropower junction groups are very necessary to carry out risk analysis. In risk analysis, it is important to obtain accurate dam-break flood flow and flood evolution process to analyze the influence of dam-break flood on the subordinate reservoirs. The prior patent document CN 112749475 discloses a method for determining the continuous burst risk analysis of a cascade reservoir group, which comprises the processes of collecting, determining and modeling basic data such as main characteristic parameters of a dam for a selected continuous dam burst risk analysis object. The prior patent document CN11046563 discloses a continuous burst flood simulation method of a cascade reservoir group, which comprises the steps of extracting river network information, carrying out evolution calculation on flood in a river channel, carrying out flood regulation calculation on a reservoir, taking the whole dam burst outflow process as the process of inflow of flood in a downstream river section of a dam, and has high requirement on obtained information, complex calculation process, practical emphasis on the flood evolution process and insufficient applicability of analysis results. The prior patent document CN107330274 discloses a soil-rock dam group control cascade water discharge safety calculation method considering upstream dam-break flood, which is a method for improving the safety of a downstream dam by analyzing the calculation results of upstream, midstream and downstream dam-break flood evolution and flood regulation processes. However, the method is only suitable for earth and rockfill dams, and cannot be applied to other types of dams. It can be seen that the prior art still lacks a mature and complete computational analysis method for the continuous burst problem of the cascade hydropower junction group. Disclosure of Invention Aiming at the defects of the prior art, the invention aims to provide a novel cascade hydroelectric junction group dam continuous-bursting risk analysis method and system, the application range of the method is wide, excessive basic data do not need to be collected, the calculation efficiency is greatly improved, the conditions of all dam collapse of the dam, which can generate lower-level influence, in the outflow region can be accurately analyzed, the controllable reservoir in the outflow region can be intuitively judged, and the continuous collapse risk prevention and control capability of the cascade hydropower junction group is remarkably improved. The technical scheme of the invention is as follows: a cascade hydroelectric junction group dam continuous collapse risk analysis method, which comprises the following steps: s1, constructing a dam continuous-bursting physical model of a step hydroelectric junction group, wherein continuous bursting comprises continuous dam-breaking and/or overtopping; S2, constructing a dam-break flood flow calculation model based on the dam continuous-break physical model, and obtaining the flow of flood which is evolved to the next-stage dam after the dam of any-stage dam except the last-stage dam breaks or overturns according to the dam-break flood flow calculation model; s3, constructing a dam break occurrence condition analysis model based on the dam continuous break physical model, and obtaining the conditions of dam break or roof break of any one of the stages of dams except the final stage of dam, whether the next stage of dam breaks or roof break, dam break flow or barrage flow generated after the dam break or roof break occurs and the conditions of dam break and roof break; S4, obtaining physical parameters of each dam in the cascade hydroelectric junction group to be subjected to continuous collapse risk analysis, and determining whether each dam is collapsed or overturned and the flood evolution condition after the collapse or overtravel occurs through the dam continuous collapse physical model, the dam collapse flood flow measuring model and the dam collapse occurrence condition analysis model. According to some pre