Small reservoir dam safety health degree evaluation system and method

Abstract

The application discloses a small reservoir dam safety health degree evaluation system, which comprises a field safety inspection module, a safety monitoring data analysis module, a flood control capacity rechecking module, a seepage safety evaluation module, a structure safety evaluation module and a dam safety health degree overall evaluation module. The application adopts multi-source information to comprehensively evaluate the safety of the dam, and reduces the uncertainty and subjective influence in dam service behavior evaluation and early warning process.

Description

Technical Field

[0001] This invention relates to the field of model algorithm construction, specifically to a safety and health evaluation model for small reservoir dams, which is particularly suitable for the safety analysis of small reservoir dams. Background Technology

[0002] Currently, numerous reservoirs have been built across the country. However, due to their large number, wide distribution, and inconvenient transportation, small reservoirs are characterized by low design standards and insufficient maintenance funds. Accidents and dam breaks in small reservoirs are frequent. In response to these issues, smart water conservancy platforms provide analytical models for reservoir dam safety, but most are primarily statistical models driven by monitoring data. However, given the incomplete monitoring data and low precision calibration of monitoring instruments for small reservoirs, single monitoring data cannot reflect the comprehensive safety of small reservoir dams. Therefore, it is necessary to adopt a multi-source information fusion perspective, considering the comprehensive conditions of the dam (basic information, monitoring data, and on-site inspection data), to further quantify and analyze the safety of reservoir dams. Summary of the Invention

[0003] Purpose of the invention: The technical problem to be solved by the present invention is to provide a safety and health evaluation system for small reservoir dams, which addresses the shortcomings of the existing technology.

[0004] To address the aforementioned technical problems, this invention discloses a safety and health assessment system for small reservoir dams, comprising a field safety inspection module, a safety monitoring data analysis module, a flood control capacity verification module, a seepage safety assessment module, a structural safety assessment module, and a dam safety and health overall rating module, wherein:

[0005] The on-site safety inspection module is used to evaluate the level of on-site inspection of the dam based on the inspection findings. The on-site inspection includes the dam crest, dam body, dam abutments, downstream ground, and reservoir bank near the dam. The module's score is obtained by inspecting these areas.

[0006] The safety monitoring data analysis module sets up displacement statistical models, piezometer statistical models, and seepage flow models according to different monitoring types. It adopts a multi-factor time-varying model to establish a statistical model between external loads and effect values, thereby obtaining the effect values ​​under the current load conditions. Based on the obtained effect values, it uses the confidence interval estimation method to establish a grading index and obtain the module's score.

[0007] The flood control capacity verification module evaluates the dam's flood control capacity by comparing the changes in the current water level caused by different inflow rates with the dam crest elevation, and obtains the corresponding flood control capacity score.

[0008] The seepage safety evaluation module evaluates the hydraulic gradient and leakage based on the dam's basic information and monitoring data, and derives a score for the seepage safety evaluation module.

[0009] The structural safety evaluation module calculates the score of the structural safety evaluation module through deformation control and safety factor stability analysis;

[0010] The overall safety and health rating module of the dam is used to give an overall rating of the dam's safety and health based on the scores from the on-site safety inspection module, safety monitoring data analysis module, flood control capacity verification module, seepage safety evaluation module, and structural safety evaluation module.

[0011] Specifically, the on-site safety inspection module, based on the "Guidelines for Safety Evaluation of Reservoirs and Dams" (SL 258-2017), and considering the characteristics of small reservoirs, simplifies the requirements to obtain the dam evaluation scoring table:

[0012]

[0013] Each item in the table above has three evaluation levels, each with a corresponding score: A: 100; B: 50; C: 0. The total score for the on-site safety inspection module is:

[0014] (1)

[0015] in, Let j be the on-site safety rating score. To Calculate the average value, where if any part of the site inspection is rated as level C, the dam rating is classified as high risk.

[0016] The on-site safety inspection module can be scored. The classes are divided into: Class 4 (0, 25), Class 3 (25, 50), Class 2 (50, 75), and Class 1 (75, 100).

[0017] The displacement statistical model during the dam's operation period is shown in formula (2), from which the displacement effect value can be obtained. : (2)

[0018] In the formula: These are constant regression coefficients (displacement model); , For water level-related regression coefficients (displacement model); , , , For time-effect regression coefficients (displacement model); , The corresponding water levels of the upstream and downstream reservoirs on day i are for monitoring. To calculate the starting time, ;

[0019] The statistical model of the piezometer for earth-rock dams is shown in equation (3), from which the effect value of seepage pressure can be obtained. : (3)

[0020] In the formula: These are constant regression coefficients (pipe compression model); The average water level correlation regression coefficient (pipe pressure model). For rainfall regression coefficients (pipe pressure model); , The time-effect regression coefficient (pipe pressure model). The upstream water level is the average value of the previous i days; The average rainfall over the previous i days;

[0021] The seepage flow model for earth-rock dams uses formula (4) to obtain the effect value of seepage flow. : (4)

[0022] In the formula: These are constant regression coefficients (seepage flow model); , For water level-related regression coefficients (seepage flow model); The average water level correlation regression coefficient (seepage flow model). For rainfall regression coefficients (infiltration model); , For time-effect regression coefficients (seepage flow model);

[0023] Based on observational data and environmental variables, a statistical mathematical model (Equations 2-4) can be established to obtain effect values ​​for different types of situations. and its confidence interval :

[0024] (5)

[0025] In the formula: ; The standard deviation of the statistical model; For significance level of The function, where, ; If the measured value is in If the dam is within the acceptable range, it is considered to be operating safely; otherwise, it may be abnormal. Therefore, the control indicators for the monitoring quantities ( It can be written as: (6)

[0026] The measured values ​​were then compared with the control index range to obtain the safety monitoring data rating score. The scores are 100, 50, and 0 respectively; therefore, the total score of the safety monitoring data analysis module is: (7)

[0027] The safety monitoring data analysis module can be scored The classes are divided into: Class 4 (0, 25), Class 3 (25, 50), Class 2 (50, 75), and Class 1 (75, 100).

[0028] The flood control capability verification module obtains the flood control capability score using the following method: (wherein, the predicted water level h is...) y The solution can be obtained iteratively using the water balance equation, as shown in the following formula: (8)

[0029] In the formula: A s The area of ​​the reservoir; z s The reservoir level is represented by t; time is represented by Q. in For inbound flow; Q spill For the spillway discharge; Q sluice The outflow rate of the gate;

[0030] The predicted water level h can be obtained through the water balance equation. y Based on actual engineering data, the dam crest elevation h d Based on the initial water level h0, the corresponding flood control capacity score can be obtained: (9)

[0031] The flood control capacity verification module can be scored The classes are divided into: Class 4 (0, 25), Class 3 (25, 50), Class 2 (50, 75), and Class 1 (75, 100).

[0032] The critical hydraulic gradient adopts the piping type with the highest risk factor, and the allowable hydraulic gradient can be calculated using equation (10). Its expression is: (10)

[0033] In the formula: The soil permeability coefficient; The particle size corresponding to soil particles whose weight is less than 3% of the total soil weight; n is the porosity. Hydraulic gradient threshold. The secondary control index can be obtained by adjusting the allowable hydraulic gradient through a threshold coefficient (C), as follows: (11)

[0034] In the formula: The hydraulic gradient threshold is for level C; C represents the threshold coefficients of 0.8 and 1.2, which can be adjusted according to the importance of the hydraulic structure; by comparing the range of the control index for the hydraulic gradient monitored at level j, the seepage safety rating score can be obtained. ): 100, 50, 0;

[0035] Regarding leakage rate, allowable leakage rate It can be obtained based on upstream and downstream water levels and dam geometry, and the specific expression is as follows: (12)

[0036] In the formula, This refers to the upstream water level elevation. The downstream water level is the elevation; L is the horizontal distance between the upstream and downstream water levels, such as... Figure 3 As shown. Leakage threshold. The secondary control index can be obtained by adjusting the allowable hydraulic gradient through a threshold coefficient (C), as follows: (13)

[0037] In the formula: The threshold for seepage flow at level C is given, where C is a threshold coefficient of 0.8 or 1.2, which can be adjusted according to the importance of the hydraulic structure. The seepage safety rating score can be obtained from the range of the control index for the j-th monitored seepage flow. ): 100, 50, 0.

[0038] By summing up the scores for each hydraulic gradient and seepage flow rate, the score for the seepage safety evaluation module can be calculated using the following formula: (14)

[0039] The seepage safety assessment module rating can be determined by a score. The classes are divided into: Class 4 (0, 25), Class 3 (25, 50), Class 2 (50, 75), and Class 1 (75, 100).

[0040] Using the maximum dam height (H) max Using 1% and 3% as secondary control indicators, the safety of deformable structures is discussed in a tiered manner. The following formula is used to obtain: (15)

[0041] In the formula: Let C be the maximum dam height, and C be the threshold coefficients of 0.01 and 0.03 respectively. The corresponding structural safety rating score can be obtained from the range of the control index for the j-th monitored settlement displacement. ): 100, 50, 0;

[0042] According to the "Code for Design of Slopes in Water Conservancy and Hydropower Projects" (SL386-2007), the two-level control indicators for stability and structural safety are ( It can be determined by the following formula: (16)

[0043] Where: permissible safety factor The value is 1.1, and C is the threshold coefficient, which is 1.0 and 1.2 respectively. The safety factor is calculated from this. By comparing the control index range, the corresponding structural safety rating score can be obtained. ): 100, 50, 0. The safety factor is determined by the Swedish slice method. When the soil structure is discretized into m soil strips for analysis, according to the principle of limit equilibrium, the sliding moment = the resisting moment, and the safety factor... Then we have: (17)

[0044] In the formula: , , Let be the cohesion, angle of internal friction, and weight of the m-th soil block, respectively. , , respectively, represent the length of the slip surface and the horizontal angle of the m-th soil block.

[0045] The structural safety rating scores for deformation and stability can be combined and calculated using the following formula: (18)

[0046] Submodule ratings can be determined by scores. The classes are divided into: Class 4 (0, 25), Class 3 (25, 50), Class 2 (50, 75), and Class 1 (75, 100).

[0047] The overall score for dam safety and health is expressed as follows: (19)

[0048] in, The overall score for the dam; The U-th submodule is scored, where U=1,2,3,4,5, corresponding to the on-site safety inspection module, safety monitoring data analysis module, flood control capacity verification module, seepage safety evaluation module, and structural safety evaluation module, respectively. Let U be the weight coefficient of the U-th submodule. The overall dam rating can be divided into the following categories based on the score: low risk (0, 25], medium risk (25, 50], relatively high risk (50, 75], and high risk (75, 100]; the weight coefficient range is [0, 1].

[0049] This invention also provides a method for evaluating the safety and health of small reservoir dams using the aforementioned small reservoir dam safety and health evaluation system, comprising the following steps:

[0050] (1) Basic data summary: The basic data of the dam is obtained by analyzing the basic information of the dam, the test data and the on-site inspection data. The basic information of the dam includes the dam height, the upstream and downstream slope ratio, the dam crest width, the dam bottom width, the cohesion of the dam material, the internal friction angle of the dam material, the permeability coefficient of the dam material, the reservoir capacity curve, and the discharge curve. The monitoring data includes the displacement monitoring data and its relative position, the piezometer monitoring data and its relative position, the seepage flow monitoring data and its relative position, the upstream and downstream water levels, the rainfall, the temperature, and the inflow rate.

[0051] (2) The on-site safety inspection module, safety testing data analysis module, flood control capacity verification module, seepage safety module and structural safety evaluation module are calculated in parallel to calculate the corresponding scores. The scoring is based on a 100-point scale, divided into four intervals: (75, 100], (50, 75], (25, 50], and (0, 25], and each sub-item is rated accordingly: first-class, second-class, third-class, and fourth-class.

[0052] (3) The total score for dam safety and health is calculated based on the scores of each module and expressed as follows: (19)

[0053] in, The overall score for the dam; The U-th submodule is scored, where U=1,2,3,4,5, corresponding to the on-site safety inspection module, safety monitoring data analysis module, flood control capacity verification module, seepage safety evaluation module, and structural safety evaluation module, respectively. Let U be the weight coefficient of the U-th submodule. The overall dam rating can be divided into the following categories based on the score: low risk (0, 25], medium risk (25, 50], relatively high risk (50, 75], and high risk (75, 100]; the weight coefficient range is [0, 1].

[0054] Beneficial Effects: Due to historical reasons, the basic data, monitoring data, and operational management levels of small reservoirs are generally low. Previous single-assessment systems often fail to accurately reflect the actual operating status of reservoirs due to data gaps. Against this backdrop, this invention considers the comprehensive operating conditions of small reservoirs and proposes a safety and health evaluation model for small reservoir dams based on on-site safety inspections and monitoring data analysis. According to the basic framework of the "Guidelines for Safety Evaluation of Reservoir Dams," the safety and health evaluation model for small reservoir dams is divided into five modules: 1. On-site safety inspection; 2. Safety monitoring data analysis; 3. Flood control capacity verification; 4. Seepage safety evaluation; 5. Structural safety evaluation. Based on on-site inspections, monitoring data, dam material characteristics, and measured environmental data such as reservoir water level, rainfall, and temperature, the completeness of parameters is analyzed. Therefore, based on on-site safety inspections and monitoring data, a multi-scenario, multi-output dam safety and health evaluation model suitable for small reservoirs is established. This model emphasizes the complementarity and integration of multi-source information from the perspective of fusing similar and dissimilar information, comprehensively assesses dam health, and reduces uncertainty and subjective influence in the process of dam service performance assessment and early warning. Attached Figure Description

[0055] Figure 1 A system framework diagram for the safety and health assessment model of small reservoir dams;

[0056] Figure 2 This is a geometric schematic diagram of a small reservoir dam.

[0057] Figure 3 This is a schematic diagram illustrating the calculation of the leakage threshold.

[0058] Figure 4 This is a schematic diagram for calculating the sliding torque. Detailed Implementation

[0059] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0060] This application reduces the uncertainty and subjective influence in the dam service performance assessment and early warning process by using multi-source information to conduct a comprehensive safety assessment of the dam.

[0061] Specifically, this application provides a safety and health assessment system for small reservoir dams, including an on-site safety inspection module, a safety monitoring data analysis module, a flood control capacity verification module, a seepage safety assessment module, a structural safety assessment module, and a dam safety and health overall rating module, such as... Figure 1 As shown.

[0062] The safety monitoring data analysis module sets up displacement statistical models, piezometer statistical models, and seepage flow models according to different monitoring types. It adopts a multi-factor time-varying model to establish a statistical model between external loads and effect values, thereby obtaining the effect values ​​under the current load conditions. Based on the obtained effect values, it uses the confidence interval estimation method to establish a grading index and obtain the score of this module.

[0063] The flood control capacity verification module evaluates the dam's flood control capacity by comparing the changes in the current water level caused by different inflow rates with the dam crest elevation, and obtains the corresponding flood control capacity score.

[0064] The seepage safety assessment module evaluates the hydraulic gradient and leakage based on the dam's basic information and monitoring data, and derives a score for the seepage safety assessment module.

[0065] The structural safety evaluation module calculates its score based on two aspects: deformation control and safety factor stability analysis.

[0066] The overall safety and health rating module of the dam is used to give an overall rating of the dam's safety and health based on the scores from the on-site safety inspection module, safety monitoring data analysis module, flood control capacity verification module, seepage safety evaluation module, and structural safety evaluation module.

[0067] The scoring methods for each module are explained in detail below.

[0068] The dam foundation data was obtained based on the dam foundation information, testing data, and on-site inspection data. The dam foundation information includes dam height, upstream and downstream slope ratio, dam crest width, dam base width, dam material cohesion, dam material internal friction angle, dam material permeability coefficient, reservoir capacity curve, and discharge curve. The monitoring data includes Boakai displacement monitoring data and its relative position, piezometer monitoring data and its relative position, seepage flow monitoring data and its relative position, upstream and downstream water levels, rainfall, temperature, and inflow.

[0069] (I) On-site safety inspection module (Module 1):

[0070] On-site inspection is a crucial step in assessing the health of small reservoirs. Analyzing data from previous inspections, qualitative judgments are made by examining abnormal dam appearances, their locations, patterns of change, and trends. To achieve comprehensive quantitative analysis, the inspection content needs to be scored to evaluate each inspection task. According to the "Guidelines for Safety Evaluation of Reservoirs and Dams" (SL258-2017), for small and medium-sized reservoirs, this invention assigns scores to the on-site safety of the dam according to Table 1:

[0071] Table 1. On-site scoring table for the dam

[0072]

[0073] Each item in the table above has three evaluation levels, each with a corresponding score: A: 100; B: 50; C: 0. The total score for the on-site safety inspection module is: (1)

[0074] in, Let j be the on-site safety rating score. To Calculate the average value, where if any part of the site inspection is rated as level C, the dam rating is classified as high risk.

[0075] This module's rating can be determined by a score. The classes are divided into: Class 4 (0, 25), Class 3 (25, 50), Class 2 (50, 75), and Class 1 (75, 100).

[0076] (II) Safety Monitoring Data Analysis Module (Module Two)

[0077] For small reservoirs, this invention employs a multi-factor time-varying model from the "Hydraulic Engineering Design Manual - Hydraulic Safety Monitoring" to establish a statistical model between external loads and effect values, thereby obtaining the effect values ​​under the current load conditions. Error analysis of the monitoring data is performed using confidence intervals, and the standard deviation coefficient is adjusted to determine the corresponding multi-level thresholds. Based on the different types of monitoring data, it can be divided into three sub-items: displacement, seepage pressure, and seepage flow.

[0078] a) Displacement Statistical Model. This model primarily considers the dam's operational period. The displacement of an earth-rock dam is mainly caused by consolidation, but is also influenced by reservoir water level and temperature. The settlement caused by consolidation also reflects the characteristics of time-dependent changes. The statistical model for settlement during the operational period is as follows: (2)

[0079] In the formula: These are constant regression coefficients (displacement model); , For water level-related regression coefficients (displacement model); , , , These are the time-effect regression coefficients (displacement model). , The corresponding water levels of the upstream and downstream reservoirs on day i are for monitoring. To calculate the starting time, .

[0080] B) Piezometer Statistical Model. The main influencing factors can be categorized into upstream water level components, downstream water level components, rainfall components, and time-dependent components. Considering all factors, the piezometer statistical model for earth-rock dams is written as follows: (3)

[0081] In the formula: These are constant regression coefficients (pipe compression model); The average water level correlation regression coefficient (pipe pressure model). For rainfall regression coefficients (pipe pressure model); , The time-effect regression coefficient (pipe pressure model). The upstream water level is the average value of the previous i days; denoted as the average rainfall over the previous i days.

[0082] C) Seepage Flow Model. This is mainly affected by upstream and downstream water depth, rainfall infiltration, and the time-varying processes of siltation in front of the dam and the seepage barrier. Since the material properties of earth-rock dams change relatively little with temperature, the temperature component can generally be partially considered. In summary, the statistical model for seepage flow in earth-rock dams is as follows: (4)

[0083] In the formula: These are constant regression coefficients (seepage flow model); , For water level-related regression coefficients (seepage flow model); The average water level correlation regression coefficient (seepage flow model). For rainfall regression coefficients (infiltration model); , These are the time-effect regression coefficients (seepage flow model).

[0084] D) Comprehensive evaluation of safety monitoring data. Based on observation data, establish a statistical mathematical model (Equations 2-4), and calculate different types of numerical values. ( ) and its confidence interval band : (5)

[0085] In the formula: The standard deviation of the statistical model; For significance level of functions ( ; If the measured value is within... If the dam is within the acceptable range, it is considered to be operating safely; otherwise, it may be abnormal. Therefore, the control indicators for the monitoring quantities can be written as: (6)

[0086] The measured values ​​were then compared with the control index range to obtain the safety monitoring data rating score. The scores are 100, 50, and 0 respectively. Therefore, the total score of the safety monitoring data analysis module is: (7)

[0087] Submodule ratings can be determined by scores. The classes are divided into: Class 4 (0, 25), Class 3 (25, 50), Class 2 (50, 75), and Class 1 (75, 100).

[0088] (III) Flood Control Capacity Evaluation Module (Module 3)

[0089] Flood control capacity is evaluated by considering the changes in current water level caused by different inflow rates and comparing them with the dam crest elevation. The current water level is a dynamic process, incorporating both upstream inflow and downstream discharge capacity. When calculating changes in upstream reservoir elevation, inflow, spillway discharge, and gate discharge must all be considered. The entire process follows a water balance equation: (8)

[0090] In the formula: A s The area of ​​the reservoir surface; z s The reservoir level is represented by t; time is represented by Q. in For inbound flow; Q spill For the spillway discharge; Q sluice The outflow rate of the gate;

[0091] The predicted water level h can be obtained through the water balance equation. y , and the dam crest elevation h d Based on the initial water level h0, the corresponding flood control capacity score can be obtained: (9)

[0092] Module 3 rating can be determined by scoring. The classes are divided into: Class 4 (0, 25), Class 3 (25, 50), Class 2 (50, 75), and Class 1 (75, 100), with corresponding computational geometry diagrams as follows. Figure 2 As shown.

[0093] (iv) Seepage Safety Assessment Module (Module 4)

[0094] This submodule evaluates the dam's seepage safety based on its basic information and monitoring data, and the evaluation is divided into two aspects: hydraulic gradient and leakage rate.

[0095] A) Regarding the hydraulic gradient, this invention calculates the hydraulic gradient based on seepage pressure monitoring data and relative location. The corresponding seepage stability score is obtained by comparing it with multi-level hydraulic gradient thresholds. The calculation methods for the allowable hydraulic gradient are all derived from the "Code for Geological Investigation of Hydraulic and Hydropower Engineering". The critical hydraulic gradient adopts the piping type with the highest risk factor, and its expression is: (10)

[0096] In the formula: The soil permeability coefficient; The particle size of soil particles that account for less than 3% of the total soil weight is denoted as n; n is the porosity.

[0097] The hydraulic gradient is allowed to be controlled by a threshold coefficient (C) to obtain two levels of control indicators, which are divided into three intervals: (11)

[0098] In the formula: The hydraulic gradient threshold is for level C; C represents the threshold coefficients of 0.8 and 1.2, which can be adjusted according to the importance of the hydraulic structure; by comparing the range of the control index for the hydraulic gradient monitored at level j, the seepage safety rating score can be obtained. ): 100, 50, 0.

[0099] B) Regarding leakage, this invention utilizes a corresponding leakage threshold to evaluate the safety of seepage monitoring data. According to the "Code for Geological Investigation of Water Conservancy and Hydropower Projects," the basic leakage calculation value can be expressed as: (12)

[0100] In the formula, This refers to the upstream water level elevation. The downstream water level is the elevation; L is the horizontal distance between the upstream and downstream water levels, such as... Figure 3 As shown.

[0101] Based on the different upstream and downstream water levels, the allowable leakage threshold q is calculated. 允许 The multi-level control indicators can be obtained according to the following formula: (13)

[0102] In the formula: The threshold for seepage flow at level C is given, where C is a threshold coefficient of 0.8 or 1.2, which can be adjusted according to the importance of the hydraulic structure. The seepage safety rating score can be obtained from the range of the control index for the j-th monitored seepage flow. ): 100, 50, 0.

[0103] C) For the comprehensive evaluation of seepage safety, the total score for this module is calculated by summing the various hydraulic gradients and seepage flows using the following formula: (14)

[0104] Submodule ratings can be determined by scores. The classes are divided into: Class 4 (0, 25), Class 3 (25, 50), Class 2 (50, 75), and Class 1 (75, 100).

[0105] (V) Structural Safety Module (Module Five)

[0106] This invention relates to a structural safety module, which consists of two sub-items: 1. Deformable structural safety analysis, and 2. Stable structural safety analysis.

[0107] A) Deformation structure safety analysis mainly refers to the "Design Code for Rolled Earth-Rock Dams" (SL274-2001), which stipulates that "the settlement of the dam crest after completion should not exceed 1% of the dam height." Years of engineering practice have shown that settlement less than 1% of the dam height after completion generally does not produce significant cracks, while settlement greater than 1% to 3% is more likely to cause cracks. Therefore, the maximum dam height (H) is adopted. max The safety of deformable structures is discussed in a tiered manner, using 1% and 3% as secondary control indicators. The following formula is used to obtain: (15)

[0108] In the formula: Let C be the maximum dam height, and C be the threshold coefficients of 0.01 and 0.03 respectively. The corresponding structural safety rating score can be obtained from the range of the control index for the j-th monitored settlement displacement. ): 100, 50, 0.

[0109] B) Stability structural safety analysis, according to the "Code for Design of Slopes in Water Conservancy and Hydropower Projects" (SL386-2007), the control indicators for stability structural safety are ( It can be determined by the following formula: (16)

[0110] In the formula: The value is 1.1, and C is the threshold coefficient, which is 1.0 and 1.2 respectively. The safety factor is calculated from this. By comparing the control index range, the corresponding structural safety rating score can be obtained. ): 100, 50, 0. The safety factor can be determined using the Swedish slice method. When the soil structure is discretized into m soil strips for analysis, according to the principle of limit equilibrium, the sliding moment = the resisting moment, and the safety factor... Then we have: (17)

[0111] In the formula: , , Let be the cohesion, angle of internal friction, and weight of the m-th soil block, respectively. , , respectively, represent the length of the slip surface and the horizontal angle of the m-th soil block.

[0112] 3) For the comprehensive evaluation of structural safety, the total score in Module 5 combines the scores for deformation and stability structural safety ratings, and can be calculated using the following formula: (18)

[0113] Submodule ratings can be determined by scores. The classes are divided into: Class 4 (0, 25), Class 3 (25, 50), Class 2 (50, 75), and Class 1 (75, 100).

[0114] (vi) Overall evaluation of the safety and health of reservoir dams (Module 5)

[0115] The overall rating of the reservoir dam is divided into four levels: low risk, medium risk, relatively high risk, and high risk. Sub-module scores are divided into four grades: Grade 1, Grade 2, Grade 3, and Grade 4 (good to poor), with scores of 25, 50, 75, and 100 for each sub-module, respectively. Therefore, the overall dam score is expressed as: (19)

[0116] in, The overall score for the dam; The U-th submodule is scored, where U=1,2,3,4,5, corresponding to the on-site safety inspection module, safety monitoring data analysis module, flood control capacity verification module, seepage safety evaluation module, and structural safety evaluation module, respectively. Let U be the weight coefficient of the U-th submodule. The overall dam rating can be divided into: low risk (0, 25), medium risk (25, 50), relatively high risk (50, 75), and high risk (75, 100); the weight coefficient ranges from [0, 1].

[0117] Application Examples

[0118] A homogeneous dam located in Hunan Province has a height of 46.30 m and an axis length of 210.00 m. Observation stations are set up at the top and downstream of the dam. Monitoring data from 2020 to 2022 were selected, and the evaluation system proposed in this invention was used to evaluate and analyze the safety and health of the dam. The evaluation is carried out in four modules: on-site safety inspection, safety monitoring data analysis, flood control capacity verification, seepage safety evaluation, structural safety evaluation, and overall dam safety and health rating.

[0119] (1) On-site safety inspection module

[0120] According to the "Guidelines for Safety Evaluation of Reservoirs and Dams" and considering the characteristics of small reservoirs, a field inspection checklist was established. Field inspectors used a mobile app to score and analyze the real-time safety status of the dam, as detailed in the table below. Based on the calculation results of the field safety inspection (Module 1), it can be concluded that the dam is in a safe operating state. According to formula (1), the corresponding module total ( The score is 100.

[0121] Table 2 Calculation Results of On-site Safety Inspection (Module 1)

[0122]

[0123]

[0124] (2) Safety monitoring data analysis module

[0125] 1) Displacement monitoring model:

[0126] Based on the settlement monitoring data of the dam section from 2020 to 2022, the displacement statistical model was obtained through stepwise regression algorithm according to equation (2):

[0127] Two confidence intervals can be obtained from the significance level:

[0128] Environmental variables: upstream water level ( 41.0m, downstream water level ( ) 1.21m, monitoring time (t) 213 days, the settlement () is calculated from equation (20) The value is 10.75 mm. According to equation (6), the two-level index ( The values ​​are: [7.39, 14.11], [5.69, 15.81]. The measured monitoring data of 15.10 mm falls between the primary and secondary indicators, and the score is (...). The value is 50, as detailed in the table below.

[0129] Table 3 Settlement data calculation results

[0130]

[0131] 2) Permeability monitoring model:

[0132] Based on the seepage pressure monitoring data of well site No. 1 from 2020 to 2022, the seepage pressure statistical model was obtained through stepwise regression algorithm according to equation (3):

[0133] Two confidence intervals can be obtained from the significance level:

[0134] Environmental variables: 1-day average upstream water level ( 41.0 m, 5-day average upstream water level ( ) 42.2 m, 2-day average rainfall ( 21.2 mm, 3-day average rainfall ( The osmotic pressure was 32.1 mm, and the monitoring time was 213 days. The calculated osmotic pressure value was obtained from equation (23). The value is 30.08 m. According to equation (6), the two-level index ( The values ​​are: [28.47, 31.69], [27.96, 32.20]. Based on the measured monitoring data of 33.1 m, this exceeds the Level 2 indicator, resulting in a score of (...). The value is 0, as detailed in the table below.

[0135] Table 4 Calculation results of seepage pressure data

[0136]

[0137] 3) Seepage monitoring model:

[0138] Based on seepage monitoring data from 2020 to 2022, a statistical model of seepage flow was obtained using a stepwise regression algorithm based on equation (4): (26) (27)

[0139] Two confidence intervals can be obtained from the significance level:

[0140] Environmental variables: upstream water level ( 41.0m, average upstream water level over 1 day ( 41.0 m, the average upstream water level over 13 days ( 39.87 m, 14-day average upstream water level ( ) 41.1 m, average daily rainfall ( 17.8 mm, 2-day average rainfall ( ) 21.2 mm, the calculated seepage flow rate is obtained from equation (26) The flow rate is 44.01 mL / s. According to equation (6), the two-level index ( The values ​​are: [36.55, 51.63], [34.16, 54.02]. The measured monitoring data of 52.11 mL / s falls between the primary and secondary indicators, and the score is (…). The value is 50, as detailed in the table below.

[0141] Table 5 Calculation results of seepage flow data

[0142]

[0143] 4) Overall score of safety monitoring data:

[0144] Based on three different statistical models—displacement, seepage, and seepage pressure—the total score of the safety monitoring data analysis module can be obtained according to equation (7). Based on the table below.

[0145] Table 6 Calculation Results of Safety Monitoring Data Analysis (Module 2)

[0146]

[0147] (3) Flood control capacity verification module

[0148] Based on the basic data of the reservoir in this example (reservoir capacity curve, discharge curve), the predicted water level can be determined using the water balance equation (Formula 8). The upstream reservoir water level is 35.0 m, the dam crest elevation is 46.30 m, and the inflow rate is obtained from hydrological data, as shown in the table below.

[0149] Table 7 Inbound Flow

[0150]

[0151] The predicted water level can be obtained from the calculation. If the depth is 37.6 m, then the flood control capacity score (F3) can be obtained from equation (9) as 77.00. The specific calculation results are shown in the table below.

[0152] Table 8 Calculation Results of Flood Control Capacity Review and Evaluation (Module 3)

[0153]

[0154] (4) Seepage safety assessment module

[0155] 1) Hydraulic gradient safety assessment

[0156] In this example, the reservoir dam is a homogeneous dam with a permeability coefficient K of 1 x 10⁻⁶. -3 The soil particle size (d3) corresponding to less than 3% of the total weight is 0.02 mm, and the porosity (n) is 0.21. According to formula (10), the allowable hydraulic gradient (J) can be obtained. 允许The value is 3.84. The two-stage control index for hydraulic gradient is obtained from the threshold coefficient:

[0157] The test hydraulic gradients were obtained from the maximum cross-sectional seepage pressure monitoring data and the corresponding coordinates: 2.2 and 3.3. According to the control indicators, the hydraulic gradient scores (f4,1, f4,2) are 100 and 50, respectively.

[0158] 2) Safety assessment of leakage volume

[0159] In this example, the upstream water level (H1) is 35.1 m, the downstream water level (H2) is 1.2 m, the horizontal distance between the upstream and downstream sides is 81.0 m, and the permeability coefficient K is 1 x 10⁻⁶. -3 cm / s, from formula (12), the allowable leakage rate ( The leakage rate is 75.0 mL / s. Two levels of control indicators for leakage rate are obtained from the threshold coefficient:

[0160] The actual leakage data at the site shows that the seepage rates at the two locations are 52.11 mL / s and 43.12 mL / s, respectively. The leakage rate score (f) is determined from the control indicators. 4,3 , f 4,4 The values ​​are 100 and 100 respectively.

[0161] 3) Overall score for the seepage safety evaluation module:

[0162] Based on the two safety evaluations of hydraulic gradient and leakage, the total score (F4) of the seepage safety module can be obtained by formula (14) as 87.5, which is rated as first class. See the table below for details.

[0163] Table 9 Calculation Results of Seepage Safety Assessment (Module 4)

[0164]

[0165] (5) Structural safety evaluation module

[0166] 1) Safety analysis of deformable structures

[0167] The maximum dam height (H) of the reservoir dam in this example max The value is 46.30 m. From formula (15), the settlement deformation control index can be obtained:

[0168] Based on the actual settlement monitoring data of points A and B at the site, which were 0.235 m and 0.514 m respectively, the safety score of the deformable structure (f) can be obtained from the control indicators. 5,1 , f 5,2 The values ​​are 100 and 50 respectively.

[0169] 2) Stability and structural safety analysis

[0170] According to the "Code for Design of Slope of Water Conservancy and Hydropower Projects", the allowable safety factor is ( Taking 1.1, the stability control index can be obtained from formula (16):

[0171] The density of the dam construction material for the example reservoir is known to be 2.3 g / cm³. 3 The cohesion is 4.23 kPa, the internal friction angle is 27.8°, and there are a total of 200 soil strips. According to formula (17), the most dangerous safety factor is 1.9. The settlement deformation score (f) can be obtained from the control index. 5,3 ) are 100 respectively.

[0172] 3) Overall score of the structural safety evaluation module

[0173] Based on deformation and stability structural safety analysis, the structural safety module (18) can be obtained. The overall score is 83.33, and the rating is first class. See the table below for details.

[0174] Table 10 Calculation Results of Structural Safety Module (Module 5)

[0175]

[0176] (5) Safety and health of reservoir dams

[0177] Based on the comprehensive scores from the five sub-modules—on-site safety inspection, safety monitoring data analysis, flood control capacity verification, seepage safety evaluation, and structural safety evaluation—the overall health of the dam was calculated to be 76.34 using the average score method (Equation 19), as detailed in the table below.

[0178] Table 11 Results of Dam Safety and Health Calculation

[0179]

[0180] This invention provides a safety and health evaluation system for small reservoir dams. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A safety and health evaluation system for small reservoir dams, characterized in that, It includes modules for on-site safety inspection, safety monitoring data analysis, flood control capacity verification, seepage safety evaluation, structural safety evaluation, and overall dam safety and health rating. The on-site safety inspection module is used to evaluate the level of on-site inspection based on the on-site inspection of the dam. The on-site inspection includes the dam crest, dam body, dam abutment, downstream ground and reservoir bank near the dam. The module's score is obtained by inspecting the above-mentioned parts. The safety monitoring data analysis module sets up displacement statistical models, piezometer statistical models, and seepage flow models according to different monitoring types. It adopts a multi-factor time-varying model to establish a statistical model between external loads and effect values, thereby obtaining the effect values ​​under the current load conditions. Based on the obtained effect values, it uses the confidence interval estimation method to establish a grading index and obtain the module's score. The flood control capacity verification module evaluates the dam's flood control capacity by comparing the changes in the current water level caused by different inflow rates with the dam crest elevation, and obtains the corresponding flood control capacity score. The seepage safety evaluation module evaluates the hydraulic gradient and leakage based on the dam's basic information and monitoring data, and derives a score for the seepage safety evaluation module. The structural safety evaluation module calculates its score through deformation control and safety factor stability analysis. The overall safety and health rating module of the dam is used to give an overall rating of the dam's safety and health based on the scores from the on-site safety inspection module, safety monitoring data analysis module, flood control capacity verification module, seepage safety evaluation module, and structural safety evaluation module. The on-site safety inspection module uses the following scoring table to evaluate the safety of the dam on-site: ； Each item in the table above has three evaluation levels, each with a corresponding score: A: 100; B: 50; C:

0. The total score for the on-site safety inspection module is: （1） in, Let j be the on-site safety rating score. To Calculate the average value, where if any part of the dam is rated as Grade C during on-site inspection, the dam is classified as high-risk. The on-site safety inspection module consists of a scoring system. The dam is divided into four classes: Class IV (0, 25], Class III (25, 50], Class II (50, 75], and Class I (75, 100]. The displacement statistical model during the dam's operation period is shown in formula (2), from which the displacement effect value is obtained. : （2） In the formula: The constant regression coefficients; , The regression coefficients are related to water level. , , , These are the regression coefficients for the time effect; , The corresponding water levels of the upstream and downstream reservoirs on day i are for monitoring. To calculate the starting time, ; The statistical model of the piezometer for earth-rock dams is shown in equation (3), from which the effect value of seepage pressure is obtained. : （3） In the formula: The constant regression coefficients; The average water level is the correlation coefficient for regression. The regression coefficient for rainfall; , These are the regression coefficients for the time effect; The upstream water level is the average value of the previous i days; The average rainfall over the previous i days; The seepage flow model for earth-rock dams uses formula (4) to obtain the effect value of seepage flow. : （4） In the formula: The constant regression coefficients; , The regression coefficients are related to water level. The average water level is the correlation coefficient for regression. The regression coefficient for rainfall; , These are the regression coefficients for the time effect; Based on observational data and environmental variables, statistical mathematical models 2-4 were established to obtain effect values ​​for different types of effects. and its confidence interval : （5） In the formula: ; The standard deviation of the statistical model; For significance level of The function, where, ; If the measured value is in If the dam's condition falls within the acceptable range, it is considered to be operating safely; otherwise, it is considered abnormal. Therefore, the control indicators for the monitoring quantities... Written as: (6) The measured values ​​were then compared with the control index range to obtain the safety monitoring data rating score. The scores are 100, 50, and 0 respectively; therefore, the total score of the safety monitoring data analysis module is: （7） The safety monitoring data analysis module consists of scoring. The classes are divided into: Class 4 (0, 25], Class 3 (25, 50], Class 2 (50, 75], and Class 1 (75, 100]. The flood control capability verification module obtains the flood control capability score using the following method; wherein, the predicted water level h y The solution is obtained through iterative analysis of the water balance equation, and the specific formula is as follows: （8） In the formula: A s The area of ​​the reservoir surface; z s The reservoir level is represented by t; time is represented by Q. in For inbound flow; Q spill For the spillway discharge; Q sluice The outflow rate of the gate; The predicted water level h is obtained through the water balance equation. y Based on actual engineering data, the dam crest elevation h d Based on the initial water level h0, the corresponding flood control capacity score is obtained: （9） The flood control capability review module consists of a scoring system. The classification is as follows: Class IV (0, 25], Class III (25, 50], Class II (50, 75], and Class I (75, 100]. The critical hydraulic gradient adopts the piping type with the highest risk factor, and the allowable hydraulic gradient is calculated using formula (10). Its expression is: （10） In the formula: The soil permeability coefficient; The soil particle size is defined as the percentage of soil particles whose weight is less than 3% of the total soil weight; n is the porosity; and the hydraulic gradient threshold is... The secondary control index is obtained by adjusting the allowable hydraulic gradient through a threshold coefficient C, and its specific form is as follows: （11） In the formula: The hydraulic gradient threshold for level C is defined by C, where C is a threshold coefficient of 0.8 or 1.2, adjusted according to the importance of the hydraulic structure. The seepage safety rating score is obtained by comparing the range of the control index for the monitored hydraulic gradient of level j. : 100, 50, 0; Regarding leakage rate, allowable leakage rate Based on upstream and downstream water levels and dam geometry, the specific expression is as follows: （12） In the formula, This refers to the upstream water level elevation. Downstream water level elevation; L is the horizontal distance between upstream and downstream water levels; leakage threshold. The secondary control index is obtained by adjusting the allowable hydraulic gradient through a threshold coefficient C, and its specific form is as follows: （13） In the formula: The seepage threshold is set at level C, where C is a threshold coefficient of 0.8 or 1.2, adjusted according to the importance of the hydraulic structure. The seepage safety rating score is obtained from the range of the control index against the j-th monitored seepage flow. : 100, 50, 0; The scores for each hydraulic gradient and seepage flow rate are summarized, and the score for the seepage safety evaluation module is calculated using the following formula: （14） The seepage safety assessment module consists of a scoring system. The classes are divided into: Class 4 (0, 25], Class 3 (25, 50], Class 2 (50, 75], and Class 1 (75, 100]. Using the maximum dam height H max Using 1% and 3% as secondary control indicators, the safety of deformable structures is discussed in a tiered manner. The following formula is used to obtain: （15） In the formula: Let C be the maximum dam height, and C be the threshold coefficient, which is 0.01 and 0.03 respectively. The corresponding structural safety rating score is obtained by comparing the range of the control index for the j-th monitored settlement displacement. : 100, 50, 0; Two-level control indicators for stability and structural safety Determined by the following formula: （16） Where: permissible safety factor The value is 1.1, and C is the threshold coefficient, which is 1.0 and 1.2 respectively. The safety factor is calculated from this. By comparing the control index range, the corresponding structural safety rating score is obtained. : 100, 50, 0; The safety factor is determined by the Swedish slice method. When the soil structure is discretized into m soil strips for analysis, according to the principle of limit equilibrium, the sliding moment = the resisting moment, and the safety factor is... Then we have: (17) In the formula: , , Let be the cohesion, angle of internal friction, and weight of the m-th soil block, respectively. , and represent the length of the slip surface and the horizontal angle of the m-th soil block, respectively; The structural safety rating scores for deformation and stability are summed and calculated using the following formula: （18） The structural safety evaluation module rating is based on scores. The classes are divided into: Class 4 (0, 25], Class 3 (25, 50], Class 2 (50, 75], and Class 1 (75, 100]. The overall score for dam safety and health is expressed as follows: （19）； in, The overall score for the dam; The U-th submodule is scored, where U=1,2,3,4,5, corresponding to the on-site safety inspection module, safety monitoring data analysis module, flood control capacity verification module, seepage safety evaluation module, and structural safety evaluation module, respectively. Let U be the weight coefficient of the U-th submodule. The overall dam rating is divided into the following categories based on the score: low risk (0, 25], medium risk (25, 50], relatively high risk (50, 75], and high risk (75, 100]; the weight coefficient range is [0, 1].

2. A method for evaluating the safety and health of small reservoir dams based on the small reservoir dam safety and health evaluation system described in claim 1, comprising the following steps: (1) Basic Data Summary: Basic dam data was obtained by analyzing dam foundation information, testing data, and on-site inspection data. The basic information of the dam includes dam height, upstream and downstream slope ratio, dam crest width, dam base width, dam material cohesion, dam material internal friction angle, dam material permeability coefficient, reservoir capacity curve, and discharge curve; the monitoring data includes displacement monitoring data and its relative position, piezometer monitoring data and its relative position, seepage flow monitoring data and its relative position, upstream and downstream water levels, rainfall, temperature, and inflow. (2) The on-site safety inspection module, safety testing data analysis module, flood control capacity verification module, seepage safety module and structural safety evaluation module are calculated in parallel to calculate the corresponding scores. The scoring is based on a 100-point scale, divided into four intervals: (75, 100], (50, 75], (25, 50], and (0, 25], and each sub-item is rated accordingly: first-class, second-class, third-class, and fourth-class. (3) The total score for dam safety and health is calculated based on the scores of each module and expressed as follows: （19） in, The overall score for the dam; The U-th submodule is scored, where U=1,2,3,4,5, corresponding to the on-site safety inspection module, safety monitoring data analysis module, flood control capacity verification module, seepage safety evaluation module, and structural safety evaluation module, respectively. Let U be the weight coefficient of the U-th submodule. The overall dam rating is divided into the following categories based on the score: low risk (0, 25], medium risk (25, 50], relatively high risk (50, 75], and high risk (75, 100]; the weight coefficient range is [0, 1].

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