Earth and rockfill dam burst peak flow prediction method and storage medium

Abstract

The invention discloses an earth and rockfill dam burst peak flow prediction method and a storage medium, and belongs to the technical field of hydraulic engineering technologies. On the basis of continuous arrangement and expansion of a historical database, a comprehensive database containing outburst case information of 295 earth and rockfill dams is formed, and correlation analysis is carried out on different dam break parameters and outburst peak discharge. Extracting five influence parameters of reservoir capacity above the bottom of the breach during dam break, dam height, dam reservoir capacity, final depth of the breach and water depth above the bottom of the breach during outburst, and constructing a new earth and rockfill dam outburst parameter prediction model considering different dam types and outburst modes. Compared with 20 groups of typical parameter models existing at home and abroad, the calculation result shows that the root mean square error (Erms) and the correlation coefficient (R2) of the provided prediction model are 0.38 and 0.82 respectively, and compared with other models, the model has certain advantages, and the accuracy of the model is verified.

Description

Technical Field

[0001] The present invention relates to the technical field of water conservancy engineering technology, and more specifically, to a method for predicting peak flow rate of earth-rock dam breach and a storage medium. Background Art

[0002] According to the survey and research of ICOLD and ChinCOLD: So far, 3,356 earth-rock dams (including panel dams) have failed, accounting for 94.32% of the total number of dam failures, exceeding their share of 91.80% in the total number of dams. The manifestation is mainly due to the fact that earth-rock dams cannot resist flood overtopping like rigid dams. Therefore, it is of great scientific significance to quickly and accurately predict the peak flow of earth-rock dam failure, which is of great scientific significance for accurately calculating the flood and scientifically evaluating the consequences of earth-rock dam failure.

[0003] The existing calculation models for the peak burst flow of earth-rock dams are summarized in Table 1.

[0004] Table 1 Existing calculation models for peak flow of earth-rock dam breach

[0005]

[0006]

[0007] In Table 1, Q p is the peak flow rate of the breach, V w H is the reservoir capacity above the breach bottom when the dam breaks, w H is the water depth above the bottom of the breach when the dam breaks. b is the breach depth, H d is the dam height, g is the gravitational acceleration, H0 = 1m; for overtopping dam failure, k M =1.85; for seepage damage dam break, k M =1; when H b <6.1m, k H =1; when H b >6.1m, k H =(h b / 6.1) 1 / 8 .

[0008] Although there are many models for predicting flood peak flow parameters of earth-rock dams, most of them have not considered the influence of dam type on the flood peak flow. The differences in dam structure and anti-seepage materials between homogeneous dams, core wall dams and face dams also lead to completely different breach mechanisms and processes. Therefore, it is of great significance to classify and predict the flood peak flow of different dam types. Although the model of Xu and Zhang (Reference 1: Xu Y, Zhang M L. Breaching Parameters for Earth and Rockfill Dams [J]. Journal of Geotechnical and Geoenvironmental Engineering, 2009, 135 (12): 1957-1970) takes into account the dam type and dam breach mode, the model currently has few application database cases, resulting in the need to improve the accuracy of the prediction results. However, the model proposed by Zhong Qiming (Reference 2: Chen Lingchun, Zhong Qiming, Mei Shengyao, et al. Numerical simulation of the continuous breach process of two-stage barrier dams and study on the evolution characteristics of breach flow [J]. Journal of Hydraulic Engineering, 2024, 55(04): 493-504) only predicts core wall dams and homogeneous dams, and has not yet constructed a peak flow prediction model for panel dams, nor has it considered the impact of breach mode on the peak flow of the breach. Summary of the invention

[0009] The purpose of this application is to address the deficiencies of the above-mentioned prior art and provide a method and storage medium for predicting the peak flow rate of a dam burst based on erosion characteristics.

[0010] The technical solution of this application is as follows:

[0011] A method for predicting the peak flow rate of earth-rock dam burst is a method for predicting the peak flow rate of earth-rock dam burst under the overtopping failure form, which is determined by the following formula:

[0012]

[0013] Among them, Q P Indicates the peak flow rate of earth-rock dam breach, in m 3 / s; S represents the dam storage capacity, the unit is 10 6 m 3 ;H d Indicates the height of the dam, in meters; V w Indicates the reservoir capacity above the bottom of the breach when the dam breaks, in units of 10 6 m 3 ;H b Indicates the final depth of the breach, in meters; H w It indicates the water depth above the bottom of the breach when the dam breaks, in meters.

[0014] A method for predicting the peak flow rate of earth-rock dam burst is a method for predicting the peak flow rate of earth-rock dam burst under the form of seepage failure, which is determined by the following formula:

[0015]

[0016] Among them, Q P Indicates the peak flow rate of earth-rock dam breach, in m 3 / s; S represents the dam storage capacity, the unit is 10 6 m 3 ;H d Indicates the height of the dam, in meters; V w Indicates the reservoir capacity above the bottom of the breach when the dam breaks, in units of 10 6 m 3 ;H b Indicates the final depth of the breach, in meters; H w It indicates the water depth above the bottom of the breach when the dam breaks, in meters.

[0017] A method for predicting the peak flow rate of earth-rock dam burst is a method for predicting the peak flow rate of core wall dam burst, which is determined by the following formula:

[0018]

[0019] Among them, Q P Indicates the peak flow rate of earth-rock dam breach, in m 3 / s; S represents the dam storage capacity, the unit is 10 6 m 3 ;H d Indicates the height of the dam, in meters; V w Indicates the reservoir capacity above the bottom of the breach when the dam breaks, in units of 10 6 m 3 ;H b Indicates the final depth of the breach, in meters; H w It indicates the water depth above the bottom of the breach when the dam breaks, in meters.

[0020] A method for predicting the peak flow rate of earth-rock dam burst is a method for predicting the peak flow rate of concrete face dam burst, which is determined by the following formula:

[0021]

[0022] Among them, Q P Indicates the peak flow rate of earth-rock dam breach, in m 3 / s; S represents the dam storage capacity, the unit is 10 6 m 3 ;H d Indicates the height of the dam, in meters; V wIndicates the reservoir capacity above the bottom of the breach when the dam breaks, in units of 10 6 m 3 ;H b Indicates the final depth of the breach, in meters; H w It indicates the water depth above the bottom of the breach when the dam breaks, in meters.

[0023] A storage medium, characterized in that it stores a computer program capable of running the aforementioned earth-rock dam breach peak flow prediction method.

[0024] The beneficial effects of this application are:

[0025] First, this study further collected the latest earth-rock dam failure cases and established a large database summarizing 295 cases at home and abroad.

[0026] Second, based on this database, statistical analysis was conducted on the dam type, dam height, reservoir capacity and breach mode of earth-rock dams. The correlation analysis of breach parameters was conducted on earth-rock dam cases with detailed information. The correlation between breach parameters and peak flood flow is from strong to weak: dam reservoir capacity (S), reservoir capacity above the breach bottom at the time of dam breach (V w ), final breach depth (H b ), dam height (H d ), water depth above the bottom of the breach when the dam breaks (H w ), average width of the dam (W ave ).

[0027] Third, based on 132 sets of complete dam breach cases, combined with 20 existing typical earth-rock dam breach flow prediction models, a comparative analysis was conducted with the prediction model proposed in this paper. By comparing the prediction results of each model, it was found that the prediction accuracy of the model with fewer actual cases and the single-parameter prediction model was significantly insufficient compared with other models. The calculation results of the model in this paper have a smaller mean square error of 0.38 and a larger coefficient of determination of 0.82, which verifies the superiority of the model.

[0028] Fourth, through the sensitivity analysis of the breach parameters, it is found that the model is sensitive to each breach parameter. The sensitivity of each parameter is from strong to weak: the water depth above the breach bottom when the dam breaks (H w ), final breach depth (H b ), the reservoir capacity above the breach bottom when the dam breaks (V w ), dam storage capacity (S), dam height (H d ).

[0029] Fifth, four typical dam break cases at home and abroad were selected to verify the model. The model's predictions for different dam types (homogeneous dam, core wall dam and panel dam) all maintained prediction errors within an acceptable range of 20%. The model has high accuracy and stability, and the predictions for core wall dam and panel dam are much smaller than those of other models, which has obvious superiority and further verifies the necessity of considering dam types in the model. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be further described in detail below in conjunction with the embodiments in the accompanying drawings, but this does not constitute any limitation to the present invention.

[0031] Figure 1 It's LgQ P ~LgH b The relationship diagram between .

[0032] Figure 2 It's LgQ P ~LgH d The relationship diagram between .

[0033] Figure 3 It's LgQ P ~LgH w The relationship diagram between .

[0034] Figure 4 It's LgQ P ~LgV w The relationship diagram between .

[0035] Figure 5 It's LgQ P Relationship diagram between ~LgS.

[0036] Figure 6 It's LgQ P ~LgW ave The relationship diagram between .

[0037] Figure 7 This is a comparison chart between the calculated value and the measured value of the flood peak flow in this application.

[0038] Figure 8 This is a comparison chart of the calculation results of the calculation method of the present application and 20 existing methods.

[0039] Fig. 9 This is the error diagram of peak flood flow prediction of different models. DETAILED DESCRIPTION

[0040] The present invention is described in detail below in conjunction with specific implementation modes.

[0041] <Example 1: A method for predicting peak flow rate of earth-rock dam breach>

[0042] <1. Construction of earth-rock dam breach information database>

[0043] As shown in Table 2, a database containing 295 earth-rock dam failure information was established. In the earth-rock dam failure information database, basic information such as the country where the earth-rock dam is located, dam name, dam type, failure type, and dam height (H d ), dam storage capacity (S), final breach depth (H b ), water depth above the bottom of the breach when it breaks (H w ) and storage capacity (V w ) Peak burst flow (Q p ) and other breach data. Each breach case contains several key breach parameters. Since breaches are emergencies, it is difficult to collect breach data and there are some data missing in the database. Therefore, among the 295 breach cases, the ones with relatively complete data are selected for model construction.

[0044] Table 2 Earth-rock dam breach information database

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052] Note: O is overtopping failure, P is seepage failure, HD is homogeneous dam, CD is core wall dam, FD is face dam. <2. Selection of burst flow parameters for earth-rock dams of different dam types>

[0053] There are many factors that affect the failure process of earth-rock dams. When predicting the peak flow of a uniform dam, core wall dam or face dam, the dam capacity (S), dam height (H) and other factors are often considered. d ), average width of the dam (W ave ), the reservoir capacity above the breach bottom when the dam breaks (V w ), water depth above the bottom of the breach when the dam breaks (H w ) and the final depth of the breach (H b )These 6 parameters all play a vital role.

[0054] Therefore, cases with complete data were selected from the database to conduct correlation analysis between the outburst parameters and the outburst peak flow, as shown in 1~ Figure 6 .

[0055] If the peak flow of earth-rock dam burst can be expressed by the power exponent of a certain burst parameter of the dam, then there is a strong linear correlation between the logarithm of the peak flow and its logarithm, and the parameters with strong correlation are selected as the input parameters of the model.

[0056] Depend on Figure 1 It can be found that the slope of the best fitting line is the largest, indicating that the final depth of the breach (H b ) is the factor that determines the peak discharge of earth-rock dam burst (Q p ) magnitude. With the continuous increase of the final breach depth of the earth-rock dam, the peak flow of the earth-rock dam shows a trend of increasing. When the final breach depth exceeds 30m, the peak flow of the earth-rock dam reaches 10 4 m 3 / s or more.

[0057] Depend on Figure 2 It can be found that the height of the earth-rock dam that collapsed (H d ) is generally between 10-40m. When the height of the earth-rock dam increases to 40m, the number of earth-rock dam failure cases decreases significantly. The dam height represents its geometric characteristics. The higher the earth-rock dam height, the greater its storage capacity, the greater the potential energy of the flood, and the greater the peak flow of the silt dam failure. Although the probability of earth-rock dam failure above 40m is small, once a failure occurs, the peak flow will increase exponentially.

[0058] Figure 3 Shows the water depth above the breach bottom when the dam breaks (H w ) and the peak outburst flow (Q p ) between them.

[0059] Figure 4 It can be found that: as the reservoir capacity above the breach bottom continues to increase, the peak flow of the flood also increases significantly, and the correlation coefficient between the two is the largest.

[0060] Figure 5 The dam storage capacity (S) and the peak outburst flow (Q p ) between them.

[0061] Figure 6 Shows the average dam width (W ave ) and the peak outburst flow (Q p ), the 95% prediction interval is wide, the data dispersion is high, and the correlation coefficient R 2 The minimum is 0.14.

[0062] In summary, after the correlation analysis of the breach factors, it can be found that the correlation between the breach parameters and the peak flow of the breach is from strong to weak: the reservoir capacity above the breach bottom when the dam breaks (V w ), dam storage capacity (S), final breach depth (H b ), dam height (H d ), water depth above the bottom of the breach when the dam breaks (H w ), average width of the dam (W ave ).

[0063] According to the ranking of the correlation between breach parameters and peak flow: the reservoir capacity above the breach bottom (V w ), dam storage capacity (S), final breach depth (H b ), dam height (H d ), water depth above the bottom of the breach when the dam breaks (H w ), average width of the dam (W ave ) The number of parameters is increased successively to build a regression prediction model, and the number and type of the final model parameters are determined by judging the accuracy of each model's prediction.

[0064] Table 3 Prediction effect of different parameter models

[0065]

[0066]

[0067] Table 2 shows the prediction effect of models with different numbers of parameters. From the analysis of Table 2, we can see that the more parameters a model has, the better the prediction effect it has. However, since the number of cases for the prediction model considering 6 parameters is 35, the model may not be able to fully capture the complex real relationship between the variables due to the limited number of cases, and the model is difficult to be widely used in prediction. Therefore, the reservoir capacity above the bottom of the breach when the dam breaks (V w ), dam storage capacity (S), final breach depth (H b ), dam height (H d ), water depth above the bottom of the breach when the dam breaks (H w )These five collapse parameters are used to construct the model.

[0068] <3. Calculation model of earth-rock dam burst flow for different dam types>

[0069] The reservoir capacity above the bottom of the breach when the dam breaks (V w ), dam storage capacity (S), final breach depth (H b ), dam height (H d ), water depth above the bottom of the breach when the dam breaks (H w ) to construct the model and propose the following relationship:

[0070]

[0071] Taking the logarithm of both sides of the equation we end up with:

[0072]

[0073] Then, cases with relevant complete parameters were selected from the database of collapsed earth-rock dams for regression analysis and model building. There are 132 cases with detailed collapse information. Since the probability of seepage failure of core wall dams and face dams is small and the historical dam failure events are minimal, only the different failure modes of homogeneous dams are classified and predicted. Among them, there are 85 cases of homogeneous dams with overtopping failure, 20 cases of homogeneous dams with seepage failure, 21 cases of core wall dams with dam failure, and 5 cases of face dams with dam failure. The final prediction formula is as follows.

[0074] Homogeneous dam-overtopping failure:

[0075]

[0076] Homogeneous dam-seepage damage:

[0077]

[0078] Core wall dam:

[0079]

[0080] Panel dam:

[0081]

[0082] <4. Comparison of calculation results of different calculation models>

[0083] Table 4 Comparison of the prediction effects of different models on flood peak flow

[0084]

[0085]

[0086] Four well-known dam breach cases at home and abroad, namely the Puddingstone Dam (homogeneous dam-seepage), the Apishapa Dam (homogeneous dam-overtopping), the Banqiao Dam (core wall dam) and the Gouhou Dam (face dam), were selected for model verification. The specific calculation results obtained by applying this model are shown in Table 5.

[0087] analyze Fig. 9 We can get:

[0088] (1) When predicting the Puddingstone homogeneous dam that suffered overtopping failure, the prediction error of Zhong Qiming (2020) model was the smallest at 5.84%, the prediction error of de Lorenzo (2014) model was the largest at 98.28%, and the prediction error of this model was 10.94%, ranking second.

[0089] (2) When predicting the Apishapa homogeneous dam with seepage damage, the Azimi (2015) model has the smallest prediction error of 0.14%, the Froehlich (2016) model has the largest prediction error of 59.13%, and the prediction error of this model is 15.41%, ranking third.

[0090] (3) When predicting the Banqiao core wall dam that has overtopping failure, the prediction error of this model is as small as 9.69%, while the prediction errors of other models are all over 20%.

[0091] (4) When predicting the flow of the slab dam behind the trench that has undergone seepage damage, the prediction error of this model is 0.03%, which is significantly superior to other models. It can be seen that this model has stronger stability than other models, and can maintain a small error when predicting the flow of earth-rock dams of different dam types.

[0092] Table 5 Dam break case model prediction results

[0093]

[0094] The above embodiments are preferred implementation modes of the present invention and are only used to facilitate the description of the present invention. They are not intended to limit the present invention in any form. Any person with ordinary knowledge in the relevant technical field, if they do not depart from the scope of the technical features of the present invention, can make equivalent embodiments by partial changes or modifications to the technical contents disclosed in the present invention, and they still fall within the scope of the technical features of the present invention without departing from the technical features of the present invention.

Claims

1. A method for predicting the peak flow rate of earth-rock dam burst is a method for predicting the peak flow rate of earth-rock dam burst under the overtopping failure form, characterized in that: Use the following formula to determine: Among them, Q P Indicates the peak flow rate of earth-rock dam breach, in m 3 / s; S represents the dam storage capacity, the unit is 10 6 m 3 ;H d Indicates the height of the dam, in meters; V w Indicates the reservoir capacity above the bottom of the breach when the dam breaks, in units of 10 6 m 3 ;H b Indicates the final depth of the breach, in meters; H w It indicates the water depth above the bottom of the breach when the dam breaks, in meters.

2. A method for predicting the peak flow rate of earth-rock dam burst is a method for predicting the peak flow rate of earth-rock dam burst under the form of seepage failure, characterized in that: Use the following formula to determine: Among them, Q P Indicates the peak flow rate of earth-rock dam breach, in m 3 / s; S represents the dam storage capacity, the unit is 10 6 m 3 ;H d Indicates the height of the dam, in meters; V w Indicates the reservoir capacity above the bottom of the breach when the dam breaks, in units of 10 6 m 3 ;H b Indicates the final depth of the breach, in meters; H w It indicates the water depth above the bottom of the breach when the dam breaks, in meters.

3. A method for predicting the peak flow rate of earth-rock dam burst is a method for predicting the peak flow rate of earth-rock dam burst for core wall dam, characterized in that: Use the following formula to determine: Among them, Q P Indicates the peak flow rate of earth-rock dam breach, in m 3 / s; S represents the dam storage capacity, the unit is 10 6 m 3 ; H d Indicates the height of the dam, in meters; V w Indicates the reservoir capacity above the bottom of the breach when the dam breaks, in units of 10 6 m 3 ;H b Indicates the final depth of the breach, in meters; H w It indicates the water depth above the bottom of the breach when the dam breaks, in meters.

4. A method for predicting the peak flow rate of earth-rock dam burst is a method for predicting the peak flow rate of concrete dam burst, characterized in that: Use the following formula to determine: Among them, Q P Indicates the peak flow rate of earth-rock dam breach, in m 3 / s; S represents the dam storage capacity, the unit is 10 6 m 3 ;H d Indicates the height of the dam, in meters; V w Indicates the reservoir capacity above the bottom of the breach when the dam breaks, in units of 10 6 m 3 ;H b Indicates the final depth of the breach, in meters; H w It indicates the water depth above the bottom of the breach when the dam breaks, in meters.

5. A storage medium, characterized in that: It stores a computer program capable of running the method for predicting the peak flow rate of earth-rock dam breach as described in any one of claims 1 to 4.

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