Concrete gravity dam safety comprehensive evaluation method

Abstract

The invention discloses a concrete gravity dam safety comprehensive evaluation method, and aims to solve the problems that existing concrete gravity dam safety evaluation lacks comprehensiveness, quantification and operability, the requirement of intelligent water conservancy digital management is difficult to meet, and accurate control over the safety state of the whole dam scale of a dam cannot be achieved. Therefore, by constructing a gravity dam safety evaluation hierarchical structure model, key aspects such as structure safety recheck, field safety check and actual measurement property evaluation are comprehensively covered; meanwhile, each evaluation index is scientifically quantified by adopting a dimensionless processing technology, and the weight of each index is accurately determined by utilizing an analytic hierarchy process; finally, the comprehensive safety quantity value of the dam is obtained through calculation, and accurate and comprehensive quantitative evaluation of the safety condition of the dam is achieved. According to the method, the accuracy and reliability of evaluation are remarkably improved, the method is easy to realize by programming, a firm and powerful technical support is provided for safety management and control in intelligent water conservancy construction, and the intelligent development of the water conservancy industry is promoted.

Description

Technical Field

[0001] This invention relates to the field of water conservancy and hydropower technology, and in particular to a comprehensive safety evaluation method for concrete gravity dams. Background Technology

[0002] Concrete gravity dams, as key structures in the field of water conservancy and hydropower engineering, have been widely used in high and ultra-high dam projects due to their significant advantages such as strong structural stability and adaptability to complex geological conditions. This type of dam undertakes multiple critical tasks, including water retention, water discharge, and hydropower generation. Its safe operation is directly related to the normal functioning of the water conservancy project, playing an irreplaceable role in ensuring flood control safety, water resource supply, and stable energy output (for a related technical overview, please refer to the "Code for Design and Construction of Water Conservancy and Hydropower Projects").

[0003] Currently, the safety monitoring system for concrete gravity dams is relatively complete, forming a comprehensive monitoring network that includes various monitoring items such as environmental parameters, deformation, seepage, stress and strain, and temperature. Among these, key monitoring quantities such as dam deformation and uplift pressure at the dam foundation are considered major control indicators for safety monitoring due to their close correlation with the structural safety status. In practical applications, data acquired through automated monitoring systems are often fitted and separated using statistical models such as multiple regression. Qualitative safety assessments and early warnings are then conducted by analyzing the absolute values, rates of change, and trends of physical quantities. However, this assessment method based on a single monitoring quantity has significant limitations. It lacks a comprehensive consideration of the overall safety status of the dam and struggles to achieve quantitative evaluation at the entire dam scale, thus failing to meet the need for comprehensive and accurate control over the dam's safety condition.

[0004] Specifically, existing safety evaluation methods have the following main defects and shortcomings: 1. Partial evaluation and lack of holistic consideration: For example, while CN120672513A proposes an intelligent online monitoring method for concrete dams based on multi-source data fusion, its focus is on data validity and anomaly identification, and it falls short in comprehensively considering the overall safety status of the dam. This method often focuses on the analysis of monitoring data from a single dam section or local area, making it difficult to fully reflect the actual safety status of the dam and potentially overlooking potential risks. Similarly, CN117522128A proposes a method for calculating the safety risk value of concrete gravity dams during operation, comprehensively considering multiple risk factors and events, but it still suffers from insufficient analysis of the correlations between various risk factors, failing to fully demonstrate the safety status of the dam as a whole structure.

[0005] 2. Primarily qualitative analysis with insufficient quantitative evaluation: Existing methods, including CN120672513A and CN117522128A, primarily rely on qualitative analysis based on the absolute values, rates of change, and trends of physical quantities, lacking specific quantitative evaluation standards. This highly subjective evaluation approach struggles to meet the need for comprehensive and accurate control over dam safety, especially in complex and ever-changing engineering environments, where its limitations become particularly pronounced. While CN117522128A attempts to determine the weights and evaluation criteria of risk factors through questionnaires, it still falls under the shadow of qualitative analysis, and the accuracy and reliability of quantitative evaluation need further improvement.

[0006] 2. Insufficient multi-source data fusion and correlation analysis: Although CN120672513A proposed the concept of multi-source data fusion, in practice, the analysis of the correlation between different monitoring items remains insufficient. This makes it difficult to fully utilize the inherent connections between various monitoring items when assessing the dam's safety status, thus affecting the accuracy and comprehensiveness of the evaluation results. While CN117522128A considers multiple risk factors, it fails to fully demonstrate the complex relationships between these risk factors and how they collectively affect the overall safety status of the dam.

[0007] 3. The level of intelligence and automation needs to be improved: With the comprehensive advancement of smart water conservancy construction, engineering safety management and control systems based on the digital twin concept have become a development trend. However, existing technologies, including CN120672513A and CN117522128A, still lag significantly in terms of intelligence and automation. Current methods largely rely on manual analysis and experience-based judgment, making it difficult to achieve automation and intelligence in real-time monitoring, early warning, and decision support. Especially when dealing with large-scale monitoring data and complex engineering problems, the efficiency and accuracy of existing methods are insufficient to meet practical needs, necessitating innovative technological means to improve the level of intelligence in safety assessment.

[0008] To address the aforementioned issues, developing a safety evaluation method for concrete gravity dams that can integrate multi-source monitoring data, achieve quantitative assessment of overall safety status, and adapt to the needs of digital management has become a key issue in ensuring the safe operation of dams and promoting the construction of smart water conservancy. This invention is proposed against this backdrop, aiming to overcome the shortcomings of existing technologies through innovative technical means. By constructing a closed-loop management system covering the entire business process, it achieves end-to-end intelligent management from data collection to safety decision-making, providing more scientific, rational, and reliable decision support for the safe operation of dams. Summary of the Invention

[0009] The technical problem to be solved by this invention is to provide a comprehensive safety evaluation method for concrete gravity dams, which solves the problems that existing safety evaluation methods for concrete gravity dams lack comprehensiveness, quantification and operability, and are difficult to adapt to the needs of digital management of smart water conservancy. This method enables precise control of the safety status of the dam at all scales and provides scientific decision support for the safe operation management of dams.

[0010] To achieve the above technical objectives, this invention adopts the following technical solution: a comprehensive safety evaluation method for concrete gravity dams. This method constructs a safety evaluation system for concrete gravity dams that integrates multi-source heterogeneous monitoring data. Through standardized index quantification methods and weight calculation logic, it achieves a comprehensive quantitative evaluation of the dam's safety status. It possesses a solid theoretical foundation and a clear logical framework, is easy to program, and is compatible with engineering safety management systems based on the digital twin concept, meeting the automated and precise safety forecasting and early warning needs in smart water conservancy construction. Specifically, it includes the following four core steps, each progressively building upon the previous one, forming a complete evaluation process from index construction to level determination: Step 1: Construct a comprehensive safety evaluation index system for concrete gravity dams Establish a three-tiered evaluation indicator system: "target level - criterion level - indicator level," and clarify the core content of each level. Target layer: The comprehensive safety value of the project, that is, the overall safety status of the dam that needs to be quantified in the end; Criteria Layer: Covers three core evaluation dimensions: structural safety review, on-site safety inspection, and measured performance evaluation, which correspond to the calculated safety of the dam structure, the state of on-site physical defects, and the operational performance reflected by real-time monitoring data, respectively. Indicator layer: Based on the criteria layer, specific evaluation indicators are refined, including anti-sliding stability, dam heel and toe stress, internal stress of the dam body (belonging to structural safety review), defect status (belonging to on-site safety inspection), dam body deformation, and dam foundation seepage (belonging to measured behavior evaluation), to achieve comprehensive coverage of key factors affecting dam safety.

[0011] Step 2: Dimensionless processing and quantitative scoring of evaluation indicators To address the issue of inconsistent data units and lack of comparability among indicators in the indicator layer, three types of quantification methods are adopted based on the characteristics of the indicators to achieve the fusion of multi-source heterogeneous information: Quantification using design indices: Applicable to anti-sliding stability, dam heel and toe stress, and internal stress of the dam body. Actual values ​​of the indices are obtained through structural calculations, and the allowable values ​​specified in the code are used as a benchmark. Positive indices (anti-sliding stability, higher values ​​are better) and negative indices (dam heel and toe stress, internal stress of the dam body, lower values ​​are better) are distinguished. Linear interpolation is used to calculate the indices' scores, ensuring that the quantification results meet both code requirements and engineering realities.

[0012] Quantitative analysis is used to quantify defects in dam bodies and foundations. Based on key characteristics such as location, type, and trend of defects obtained during inspections (e.g., cracks, leaks), quantitative analysis is employed to quantify these defects, overcoming the limitations of mathematical calculations in covering qualitative indicators.

[0013] Quantification using anomaly reasoning: Applicable to dam deformation and dam foundation seepage indicators, achieving precise quantification through a three-level reasoning process: "single-point quantitative analysis - single-point multi-effect correlation analysis - multi-point multi-effect correlation analysis". Single-point quantitative analysis: Establish statistical regression, correlation analysis, principal component analysis and other equivalent effect quantity analysis models to obtain the contribution of factors such as water level, temperature and time to the monitoring value, determine whether there are regular anomalies (such as deviation from historical change patterns) or unconverged trend changes (such as long-term growth of time component), and determine the basic score of single-point measurement in combination with preset quantitative criteria. Single-point multi-effect correlation analysis: Analyze the correlation between the effects of the same category (such as deformation and seepage) and different categories (such as deformation and seepage), judge the consistency of changes in multi-effect measurements, the uniformity of reflecting structural problems and the consistency of trends, and correct the single-point score. Multi-point multi-effect correlation analysis: Based on the spatiotemporal evolution characteristics of structural failure, the correlation relationship of multiple spatial measurement points is analyzed, and the coordination of measurement distribution (such as displacement difference between adjacent dam sections), differences and trends (such as dam deformation stability and seepage pressure change along the water flow direction) are examined, and finally the quantitative score of the index is determined.

[0014] Meanwhile, in the quantification of anomaly reasoning, the scoring rules are clearly defined: the score for a single measurement point is the maximum value of the monitoring indicator score and the time-related deformation score, and the final score is calculated as "monitoring indicator score - time-related deformation score"; when multiple measurement points are fused, the lowest score of all measurement points is used as the base score, and the score is supplemented by factors such as anomaly location and effect size type to ensure that the quantification results take into account both the accuracy of individual points and the overall consistency.

[0015] Step 3: Determine the indicator weights based on the analytic hierarchy process and verify consistency. To scientifically reflect the impact of each indicator on dam safety, the Analytic Hierarchy Process (AHP) was used to calculate the weights of the criterion layer and the indicator layer, while consistency checks were conducted to ensure the rationality of the weights. Constructing a judgment matrix: The 1-9 scale method is used to compare and score the indicators at each level pairwise, and the results are summarized to construct a judgment matrix to quantify the relative importance between the indicators; Hierarchical single sorting and consistency check: After normalizing the columns of the judgment matrix, sum the results row by row, and then normalize the summation to obtain the eigenvector (i.e., the initial weights of the indicators); calculate the largest eigenvalue of the judgment matrix, and calculate the consistency index (CI) based on the largest eigenvalue. Combine this with the average random consistency index (RI) to obtain the consistency ratio (CR). When the CR meets the preset threshold, the judgment matrix passes the consistency check and the weights are valid; otherwise, adjust the matrix and re-check. Overall Hierarchical Ranking: Following the order of "Target Layer - Criterion Layer - Indicator Layer", calculate the final weight of each indicator in the indicator layer to the target layer, clarify the contribution ratio of each indicator in the comprehensive evaluation, and provide a basis for subsequent weighted calculation.

[0016] Step 4: Comprehensive safety value calculation and safety level classification Comprehensive safety value calculation: Following the calculation logic of "indicator layer - criterion layer - target layer", the evaluation value of the criterion layer (structural safety review, on-site safety inspection, and measured performance evaluation) is first calculated using the index layer score and its weight. Then, the comprehensive safety value of the target layer is calculated using the criterion layer score and its weight, so as to realize the quantitative summary from local indicators to overall safety. Safety level classification: Based on the "Guidelines for Safety Evaluation of Hydropower Station Dam Operation" and the "Guidelines for Safety Evaluation of Reservoir Dams", and combined with the needs of online monitoring, the safety level of dams is refined into five levels: A, B, C, D and E using the equal interval division method. The scoring intervals, dam operation status (such as safe, relatively safe, unsafe, etc.) and countermeasures (such as daily monitoring, special rectification, emergency reinforcement, etc.) corresponding to each level are clearly defined, ensuring that the evaluation results can directly guide engineering practice.

[0017] The present invention provides a comprehensive safety evaluation method for concrete gravity dams, which has the following beneficial effects: 1. This invention solves the specific technical problems in the comprehensive safety evaluation of concrete gravity dams in the field of water conservancy and hydropower engineering, and overcomes the limitations of the existing evaluation methods, which are one-sided, mainly qualitative, and lack comprehensive consideration.

[0018] 2. This invention provides a comprehensive safety evaluation method for concrete gravity dams that can integrate multi-source monitoring data and achieve quantitative assessment of overall safety status. The method scientifically determines the weight of each evaluation index through the analytic hierarchy process, thereby improving the accuracy and reliability of the evaluation.

[0019] 3. The evaluation method of the present invention is easy to program and can be adapted to the automated analysis needs of intelligent systems, providing strong support for safety management in the construction of smart water conservancy.

[0020] 4. This invention achieves a comprehensive consideration of the overall safety status of the dam, avoids the one-sidedness of local evaluation, and constructs a hierarchical structure model for the safety evaluation of gravity dams, which comprehensively covers key aspects such as structural safety verification, on-site safety inspection and measured performance evaluation.

[0021] 5. This invention achieves a quantitative evaluation of dam safety status through quantitative scoring and weight allocation. By combining quantitative scoring and weights, the comprehensive safety value of the dam is calculated, improving the accuracy and reliability of the evaluation. 6. The evaluation method of this invention is easy to program and can adapt to the automated analysis needs of intelligent systems, reducing the cost and error of manual intervention. It can be directly integrated into a digital twin safety management system.

[0022] 7. This invention provides scientific and reasonable decision support for dam operation safety management, helps to promptly identify and address dam safety hazards, and ensures the normal functioning of water conservancy projects. It has been verified by data from actual engineering applications.

[0023] 8. This invention is highly comprehensive, integrating multi-source data from structural calculations, inspections, and real-time monitoring, covering core influencing factors of dam safety, breaking through the limitations of traditional single-monitoring evaluation, and realizing full-scale dam safety status evaluation.

[0024] 9. The present invention provides precise quantification by designing differentiated quantification methods for different indicators and combining the analytic hierarchy process to clarify weights, thereby avoiding subjective assumptions and ensuring that the evaluation results are traceable and comparable.

[0025] 10. The present invention is highly operable, with a clear evaluation process logic and each step supported by standardized methods (such as linear interpolation, AHP calculation, and anomaly inference rules).

[0026] 11. The present invention has significant engineering value. Through the five-level safety classification and corresponding countermeasures, it provides a clear basis for the daily operation and maintenance, risk warning and emergency response of dams, and effectively ensures the safe operation of the water conservancy hub's functions such as flood control, water supply and power generation.

[0027] 12. This invention employs dimensionless processing technology, which solves the problem of inconsistent evaluation methods and data units for various indicators. It quantifies each evaluation indicator within a unified range, thereby improving the accuracy and reliability of the evaluation.

[0028] 13. This invention uses the analytic hierarchy process (AHP) to determine the weights, which scientifically and rationally determines the weights of each evaluation indicator, avoiding the influence of subjective assumptions and empiricism.

[0029] 14. This invention proposes an evaluation method based on the fusion of multi-source heterogeneous data, which solves the problems of one-sided evaluation and qualitative analysis in the existing technology.

[0030] 15. This invention, through dimensionless processing technology and analytic hierarchy process, makes the evaluation process more scientific and reasonable, and improves the accuracy and reliability of the evaluation. Attached Figure Description

[0031] Figure 1 This is a flowchart illustrating the calculation process of the comprehensive safety evaluation method for concrete gravity dams in Embodiment 6 of the present invention. Detailed Implementation

[0032] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments: Example 1 This embodiment provides a comprehensive safety evaluation method for concrete gravity dams. Taking an actual concrete gravity dam project as an example, technicians can reproduce the technical solution of this invention based on the description of this embodiment.

[0033] Step 1: Construct a hierarchical structure model for the safety evaluation of gravity dams In this embodiment, the constructed hierarchical structure model for gravity dam safety evaluation includes a target layer, a criterion layer, and an indicator layer. The target layer is set as the comprehensive safety value of the project, serving as the final output of the evaluation. The criterion layer covers three main aspects: structural safety verification, on-site safety inspection, and measured performance evaluation, specifically including key indicators such as anti-sliding stability, dam heel and dam site stress, internal stress of the dam body, defect status, dam body deformation, and dam foundation seepage. The indicator layer further refines these into quantifiable specific evaluation indicators, such as the anti-sliding stability coefficient, maximum stress at the dam heel and dam site, maximum internal stress of the dam body, defect level score, maximum dam body deformation, and maximum seepage flow at the dam foundation.

[0034] Step 2: Data Collection and Preprocessing Various monitoring data for the concrete gravity dam were collected, including stress monitoring data, deformation monitoring data, and seepage monitoring data, and preprocessed, such as data cleaning and outlier removal, to ensure the accuracy and reliability of the data. Simultaneously, design documents, construction records, operation and maintenance records, and other documentation were collected to provide a foundation for subsequent quantitative evaluation.

[0035] Step 3: Quantify each evaluation indicator To address the issue of inconsistent evaluation methods and data units among the various indicators in the evaluation index system, a dimensionless processing technique is adopted to measure each indicator within a unified range. The specific quantification method is as follows: Anti-skid stability coefficient: The measured anti-skid stability coefficient is evaluated by linear interpolation using design parameters. The measured anti-skid stability coefficient is compared with the design allowable value to obtain a quantitative score.

[0036] Maximum stress at the dam heel and dam site, and maximum stress inside the dam body: Similarly, linear interpolation evaluation is performed using design parameters. The measured stress values ​​are compared with the design allowable stress values ​​to obtain a quantitative score.

[0037] Defect rating: Quantitative analysis is used to analyze defects that cannot be quantified. A score of 0 to 10 is given based on factors such as the severity and scope of the defect.

[0038] Maximum deformation of dam body and maximum seepage flow of dam foundation: Quantitative analysis of single and multiple measuring points is carried out using anomaly reasoning. The measured deformation and seepage flow are compared with historical data and design allowable values ​​to obtain a quantitative score.

[0039] Step 4: Determine the weight of each evaluation indicator Based on the analytic hierarchy process (AHP), the weights of each individual evaluation indicator in the criterion layer and indicator layer are obtained. The specific steps are as follows: Constructing the judgment matrix: Compare each evaluation indicator pairwise to construct the judgment matrix. The element values ​​of the judgment matrix reflect the judgment of the relative importance of the two indicators.

[0040] Calculate the weights: Use the eigenvalue method to calculate the eigenvalues ​​and eigenvectors of the judgment matrix, and normalize the eigenvectors to obtain the weights of each evaluation index.

[0041] Consistency check: Calculate the consistency index and random consistency ratio of the judgment matrix, and perform a consistency check. If the consistency ratio is less than 0.1, the judgment matrix is ​​considered to have satisfactory consistency and the weight allocation is reasonable.

[0042] Step 5: Calculate the overall safety value By combining the quantitative scores and corresponding weights of each evaluation indicator, the comprehensive safety value of the dam is calculated. The specific calculation formula is: Comprehensive safety value = Σ (quantitative score of each evaluation indicator × corresponding weight).

[0043] Step 6: Security Level Classification The safety level of the dam is classified according to the preset evaluation criteria. The evaluation criteria can be set according to the actual engineering needs and safety requirements, such as dividing the comprehensive safety value into four levels: excellent (>0.8), good (0.6~0.8), average (0.4~0.6), and poor (<0.4).

[0044] Example 2 In another preferred embodiment, based on Embodiment 1, this embodiment provides a comprehensive safety evaluation method for concrete gravity dams. For different types of concrete gravity dams (such as arch dams, gravity arch dams, etc.), the criterion layer and index layer in the evaluation hierarchy model can be adjusted to adapt to the characteristics of different dam types. For example, for arch dams, evaluation indicators such as arch abutment stability and arch ring stress can be added; for gravity arch dams, the characteristics of both gravity dams and arch dams can be comprehensively considered to construct a corresponding evaluation hierarchy model. The quantitative evaluation method and weight determination method can remain unchanged to ensure the accuracy and reliability of the evaluation.

[0045] Example 3 In another preferred embodiment, based on embodiments 1 and 2 above, this embodiment provides a comprehensive safety evaluation method for concrete gravity dams, the specific method and implementation steps of which are as follows: Step 1: Construct a comprehensive safety evaluation index system for concrete gravity dams, including a target layer, a criterion layer, and an index layer. The target layer is the comprehensive safety value of the project. The criterion layer includes structural safety verification, on-site safety inspection, and measured performance evaluation. The index layer includes anti-sliding stability, dam heel and dam site stress, internal stress of the dam body, defect status, dam body deformation, and dam foundation seepage.

[0046] Step 2: In the safety evaluation index system, the evaluation methods and data units for indicators such as anti-slip stability, defect status, and deformation behavior are not unified and are not comparable. To achieve multi-source heterogeneous information fusion, it is necessary to perform dimensionless processing on each evaluation index and measure it within a unified range. For the existing evaluation index system, the quantitative methods that can be adopted include: using design indicators, using anomaly reasoning, and through quantitative analysis.

[0047] Step 2.1: Utilize design indicators: The evaluation indicators for anti-sliding stability, dam site stress, and dam body stress are all obtained through structural calculations. Therefore, the allowable values ​​specified in the code can be used to measure them.

[0048] Among the three evaluation indicators mentioned above, a higher anti-sliding stability coefficient is better, and is called a positive indicator; lower stress at the dam site and dam body is better, and is called an inverse indicator. Linear interpolation can be used to quantitatively evaluate the positive and inverse indicators, as shown below: (1) Positive indicators (taking anti-skid stability as an example) Divide the anti-slip stability safety factor obtained from the structural safety review by the allowable value (design index) under the corresponding working condition, and calculate the score of the index according to the corresponding linear interpolation formula based on the value range given in Table 1. : (5) Table 1. Quantitative Indicators for Anti-skid Stability

[0049] (2) Inverse index (taking dam stress as an example) Divide the dam stress obtained from the structural safety review by the allowable value (design index) specified in the code, and calculate the score of this index according to the corresponding linear interpolation formula based on the value range given in Table 2. : (6) Table 2. Quantitative Scoring Table for Dam Body Stress

[0050] Based on actual engineering data and design indicators, quantitative evaluations of anti-sliding stability, dam site stress, and dam body stress were calculated. Table 3 shows the structural safety review evaluation intervals and their physical significance.

[0051] Table 3 Comprehensive Evaluation and Analysis Table for Structural Safety Review

[0052] Step 2.2: Quantitative analysis: For defects in the dam body and foundation obtained through inspection that cannot be quantitatively evaluated using mathematical methods, quantitative scoring should be conducted based on the defect location, type, and trend of change. Table 4 shows the evaluation intervals and physical meanings of on-site safety inspections.

[0053] Table 4 Comprehensive Evaluation and Analysis of On-site Safety Inspection

[0054] Step 2.3: Utilizing Anomaly Reasoning: Through single-measure point quantitative analysis, single-measure point multi-effect correlation analysis, and multi-measure point multi-effect correlation analysis, a quantitative evaluation of the structure is achieved. To ensure the accuracy and universality of the diagnostic analysis results, the single-measure point anomaly reasoning analysis process must not only adapt to anomaly measures but also be able to complete reasoning for normal measures, establishing a single-measure point reasoning analysis process and quantitative method.

[0055] The main components of the reasoning analysis are as follows: Single-point evaluation and analysis: In order to achieve the goal of dam safety state diagnosis and analysis, based on the setting of monitoring indicators, it is still necessary to conduct single-point quantitative analysis to solve the problem of tracing the causes of abnormal effects; the trend evaluation rules of single-points lay the foundation for determining the degree of anomaly; and the comprehensive analysis of multiple points and multiple effects completes the comprehensive evaluation.

[0056] (I) Quantitative Analysis of Single Measurement Points To achieve single-point diagnosis, it is first necessary to establish a single-point effect quantity analysis, including models such as statistical regression, correlation analysis, and principal component analysis, to obtain the contribution degree of each causal quantity. For dam deformation, this mainly includes water level, temperature, and time-effect components. Based on this analysis, judgments can be made on the following two situations: (1) Regular abnormalities The measured values ​​of monitoring effects reflect the operational behavior of a project under load and also reflect its operational mechanism. Both the change process and distribution characteristics have their own inherent regularities. If the measured results deviate from these regularities, it indicates either that the observations themselves are unreliable or that an anomaly has occurred in the project's safety. Therefore, analyzing whether the changes in measured effects conform to their inherent regularities can serve as a criterion or qualitative indicator for judging whether the project's operational status is normal. For example, whether the dam deformation caused by water level changes is consistent with historical data.

[0057] (2) There is a trend change that has not converged. During the operation of a concrete dam, due to material creep and consolidation effects such as those from the foundation, there will be time-varying effect quantities. Under normal circumstances, the changes in effect quantities gradually slow down and eventually tend to stabilize or converge; this is the basic law of the time-history variation of effect quantities. Once a long-term trend of change in effect quantities fails to converge, it indicates an anomaly in the change of effect quantities. This anomaly may imply a lack of convergence in potential engineering changes, and may contain potential safety information, making it an important indicator for judging the safety of the project. Statistical regression models are used to obtain time-dependent components as a basis for evaluating convergence.

[0058] To accurately quantify the state of a single measurement point, the following quantification criteria are proposed: (1) When the measured values ​​show a long-term trend of non-convergence, it should be given high priority. At this time, the focus should be on analyzing and judging whether the operation of the project is normal.

[0059] (2) When the measured value changes in a way that does not conform to the expected pattern, the cause of the abnormality should be investigated. At this time, the focus should be on analyzing and judging whether the instrument’s working performance is normal or whether the engineering operation is normal.

[0060] (3) If the measured value is too large (but not too large), but the trend has converged or stabilized, it can be judged as an abnormal measured value.

[0061] (4) If the measured value does not exceed the reasonable range, but the long-term trend does not converge, it should be given high priority. At this time, the focus should be on analyzing and judging whether the operation of the project is normal.

[0062] (II) Correlation analysis of multiple effects at a single measurement point During operation, various loads generate different effects, such as deformation, seepage, stress, and strain. These effects describe the safety status of the project from different perspectives, and different monitored effects interact and influence each other, thus exhibiting a certain correlation. The correlation between different monitored effects is an important approach and indicator for analyzing the operational performance of the project.

[0063] (1) Multiple effect sizes within the same category Multiple effects within the same category refer to monitoring effects that are all of the same type, such as deformation, seepage, or stress-strain. Effects within the same category have stronger correlations; therefore, the correlations between different effects within the same category better describe the overall operational behavior of the project. For example, when measuring the internal horizontal displacement of a borehole inclinometer, the measured values ​​should have a consistent vertical distribution. Generally, the lower horizontal displacement is smaller, while the horizontal displacement is larger near the borehole opening, exhibiting a gradual "flexed" distribution. If a significant abrupt change occurs in the middle of the vertical distribution, it should be analyzed whether the inclinometer passes through a fault, fracture zone, or other weak structural surface at the abrupt measurement point, and whether the weak structural surface has undergone shear failure.

[0064] (2) Multiple effect sizes in different categories The multiple effects across different categories refer to the correlation between deformation-related, seepage-related, and stress-strain-related monitoring effects. When a canal embankment or structure as a whole experiences abnormal operational behavior, this will be reflected in different types of monitoring effects. For example, the appearance of cracks in the dam body will not only be reflected in crack gauges but may also cause an increase in seepage pressure. Especially when multiple effects simultaneously show an accelerating trend, the safety status of that part of the structure should be given high priority, as it may indicate structural anomalies.

[0065] The specific evaluation criteria are as follows: (1) If only a few isolated measuring points on the same monitoring section have larger measured values ​​or have unconverged trend changes, they can be given attention. If multiple related measuring points have larger measured values ​​or have unconverged trend changes, they should be given high priority and the operation of the monitoring section should be analyzed and judged to determine whether it is normal.

[0066] (2) If multiple monitoring points on multiple monitoring sections in the same area show similar abnormal phenomena, especially if multiple monitoring points on adjacent monitoring sections show similar abnormal phenomena, then the focus should be on analyzing and judging whether the operational status in the area has become abnormal.

[0067] Based on the quantitative analysis of single measurement points, the main contents of the correlation analysis include: whether the changes in the measured values ​​of multiple effect quantities are consistent, and whether the structural problems they reflect are the same; and the judgment of the changing trends and consistency of multiple effect quantities.

[0068] (3) Correlation analysis of multiple measurement points and multiple effects The failure process of a structure is usually gradual, and the affected area and range will gradually expand according to the structural stress adjustment process. Therefore, structural failure involves a spatiotemporal evolution process. Thus, in order to track and analyze the structural evolution process and grasp structural safety as a whole, correlation analysis of multiple measuring points and multiple effects is imperative. Based on single-point quantitative analysis and single-point multi-effect analysis, this study focuses on examining the coordination, differences, and trends in the distribution of measured values ​​at various related measuring points by analyzing the interrelationships of multiple measuring points in the structural space. For example, in terms of deformation, the dam settlement deformation should be small and tend to be stable, and the horizontal deformation of the dam should be controlled with a trend. The deformation values ​​of different parts of the dam should be coordinated, and the displacement difference between adjacent dam sections should not be too large. For concrete arch dams, the deformation of symmetrical dam sections should be coordinated. In terms of seepage, the correlation between the piezometer readings and the upstream and downstream water levels should be determined. The piezometer readings along the water flow direction should gradually decrease, especially the seepage pressure readings behind the curtain should be significantly lower than those in front of the curtain, using the design seepage pressure reduction coefficient as a control indicator. The seepage pressure and seepage flow rate need to be analyzed together to determine the effectiveness of the curtain and drainage facilities.

[0069] (III) Comprehensive Quantitative Evaluation Method To achieve quantitative assessment based on dams, a multi-measurement point collaborative analysis and scoring method is constructed, using dam sections as analysis units for comprehensive evaluation.

[0070] (1) Quantization of single measurement points The quantification method for a single measurement point combines monitoring indicators and the deformation rate over time. The scoring standard based on the classification of monitoring indicators is 10 points as the maximum score, and points are deducted according to different exceedance conditions, as shown in Table 5: Table 5. Single-point quantization method

[0071] Taking into full account the evolution process and different types of time-related components, the scoring rules are set as follows: The score for a single measurement point is the maximum of the two scores. The final score for a single measurement point is based on the monitoring indicator score minus the time-related deformation score, as shown in Table 6: Table 6. Quantitative Standards for Single Measurement Point Availability

[0072] (2) Multi-point fusion For gravity dams, the main monitoring items are deformation and seepage pressure, both of which directly affect the overall safety and stability of the dam. Therefore, based on the scores obtained from individual monitoring points, the lowest score among all monitoring points is taken as the base score for the dam section. Then, multi-monitoring point judgment rules are integrated to obtain the final score. Multi-monitoring point evaluation needs to consider the location of abnormal monitoring points, the type of effect, and the type of exceedance, etc. The following scoring rules are proposed, as shown in Table 7. The comprehensive score of the dam section is the sum of the base score and the multi-monitoring point integrated score. Table 8 shows the evaluation interval and physical meaning of the measured performance evaluation.

[0073] Table 7 Multi-point scoring rules

[0074] Table 8 Comprehensive Evaluation and Analysis Table of Measured Performance

[0075] Step 3: Based on the Analytic Hierarchy Process (AHP), obtain the weights of each individual evaluation indicator in the criteria layer and indicator layer, and perform a consistency test on them; Step 3: Based on the Analytic Hierarchy Process (AHP), obtain the weights of each individual evaluation indicator in the criteria layer and indicator layer, and perform a consistency test on them; Step 3.1: Constructing the Judgment Matrix: When determining the weights between indicators at each level, all indicators should not be compared together. Instead, they should be compared pairwise. This reduces the difficulty of comparing different indicators and improves the accuracy of the weights. A judgment matrix is ​​used for pairwise comparisons between different indicators. (8) In the formula, i and j are two different component index numbers. This indicates the relative importance of indicator 1 to the evaluation object or evaluation target within a certain level. This indicates the relative importance of indicator 1 to indicator n in relation to the evaluation object or evaluation target at a certain level, and so on. It indicates the relative importance of indicator n to the evaluation object or evaluation target at a certain level.

[0076] In the judgment matrix middle, This indicates the relative importance of indicator i to indicator j within a given level, as shown in Table 9. A 1-9 scale is used to score each indicator. A judgment matrix is ​​constructed by collecting, summarizing, and generalizing the quantitative analysis results.

[0077] Table 9. Meaning of Scale Values ​​for Judgment Matrix 1-9

[0078] Step 3.2, Hierarchical Single Ranking and Consistency Check: After obtaining the judgment matrix using the 1-9 scale method, a hierarchical single ranking is performed to rank the importance of each indicator in this level relative to a certain indicator in the higher level. The calculation steps are as follows: Step 3.2.1: Normalize each column of the judgment matrix, and use the result. This means, that is: (9) Step 3.2.2: Perform row-wise summation on each column of the normalized matrix, and use the result... This means, that is: (10) Step 3.2.3: Normalize the vector, and use the result... This means, that is: (11) The eigenvectors of the judgment matrix are obtained as W = [W1, W2, W3, ..., Wn]. T The W index is the ranking weight of an index at the same level relative to a certain index at the next higher level. This process is called hierarchical single ranking.

[0079] Step 3.2.4: Calculate the largest eigenvalue of the judgment matrix. ,Right now: (1) In the formula, Let be the i-th component of matrix AW. Let be the i-th component of the eigenvector W, and n be the order of the judgment matrix.

[0080] Step 3.2.5, Consistency Check. The purpose of performing a consistency check on the judgment matrix is ​​to examine the consistency between the importance of each indicator. Contradictory situations arise where indicator A is significantly more important than indicator B, indicator B is significantly more important than indicator C, but indicator C is more important than indicator A. Therefore, to make the judgment matrix results more scientific and consistent, a consistency check is necessary.

[0081] Calculate the consistency index (CI) of the judgment matrix: (2) If CI=0, the matrix has perfect consistency; when CI is close to 0, the matrix has satisfactory consistency; the larger CI is, the more serious the inconsistency of the matrix is.

[0082] Consistency verification requires calculating the consistency ratio (CR). (12) Wherein, RI is the average random consistency index, which can be obtained from Table 10: Table 10. Values ​​of the Average Random Consistency Index

[0083] When the calculated CR < 0.1, the judgment matrix A can be considered to have satisfactory consistency, or the inconsistency of this matrix is ​​within an acceptable range, and the judgment matrix passes the consistency test. When the CR value > 0.1, the values ​​in the judgment matrix A need to be adjusted, and steps 3.2.1 to 3.2.5 are repeated to re-perform the consistency test on the judgment matrix until the requirement of CR < 0.1 is met, thus satisfying the consistency test.

[0084] Step 3.3, Overall Hierarchical Ranking: Overall hierarchical ranking refers to the process of determining the relative importance of all indicators at a certain level to the evaluation object or objective. This process proceeds in the order from the objective level to the criterion level and then to the indicator level. For the objective level, the result of its individual hierarchical ranking is also the result of the overall ranking. When there are m indicators in the criterion level B... The feature vector sorted by weights of target layer A is: At that time, there are n indicators in the initial layer C that correspond to the indicators in the upper criterion layer B. The hierarchy but the sorted feature vector is Then, in the overall ranking of the initial layer C, the weight of the i-th indicator to the target layer A is: (13) The status values ​​of secondary indicators are obtained by scoring each secondary indicator according to the secondary indicator scoring criteria table and various monitoring data. .

[0085] Step 4: Measure each evaluation indicator to obtain the corresponding score for each evaluation indicator. Then, based on the weights of each evaluation indicator obtained by the analytic hierarchy process, obtain the final comprehensive safety value. Finally, classify the dam safety rating according to the following evaluation criteria.

[0086] Comprehensive evaluation value of dam structural safety: The established safety evaluation index system consists of three levels: Level A target layer comprehensive evaluation of dam safety, 3 Level B criterion layer indicators, and 6 Level C initial layer indicators. The evaluation value of the Level B indicators can be calculated as the weight of the Level C indicator layer relative to the Level B criterion layer and the corresponding indicator evaluation value, i.e.: (3) In the formula, The evaluation value of the criteria layer indicators. The evaluation value of the indicator layer. The weights corresponding to the indicators in the indicator layer; This can be further extended to derive a method for calculating the comprehensive evaluation value of dam structural safety. The comprehensive evaluation value can be calculated as the weight values ​​of the three B-level criterion layer indicators relative to the A-level target layer and the corresponding indicator evaluation values, namely: (4) In the formula, This is the comprehensive evaluation value for the structural safety of the dam. The evaluation value of the criteria layer indicators. The weights corresponding to the criteria layer indicators.

[0087] The "Guidelines for Safety Evaluation of Hydropower Station Dams" (DL / T5313-2014) classifies dams into normal dams, defective dams, and dangerous dams based on comprehensive evaluation results. The "Guidelines for Safety Evaluation of Reservoir Dams" (SL258-2017) classifies dams into Class I, Class II, and Class III dams. To more accurately describe the safety status of gravity dams and considering the needs of online dam monitoring, this project further subdivides the safety level of gravity dams into five levels: A, B, C, D, and E. The equal interval division method commonly used in systems engineering is adopted to classify the dam safety evaluation levels. The corresponding scoring intervals for each safety level, as well as the dam's operating status and corresponding countermeasures, are shown in Table 11. Table 11 Classification of Engineering Safety Status Evaluation Levels

[0088] Example 4 In another preferred embodiment, based on the above embodiment 3, this embodiment provides a comprehensive safety evaluation method for concrete gravity dams. Taking a concrete gravity dam as a specific embodiment, the present invention will be further described in detail: A certain reservoir concrete gravity dam has a height of 60m and consists of 8 dam sections.

[0089] Step 1: Construct an evaluation index system and establish a three-level index system: Level A (Target Level): Comprehensive safety of the dam; Level B (Sub-item Level): Structural safety review (B1), on-site safety inspection (B2), measured performance evaluation (B3); Level C (Indicator Level): Sub-item B1: Anti-sliding stability (C1), dam heel and toe stress (C2), internal stress of the dam body (C3); Sub-item B2: Defect status (C4); Sub-item B3: Dam body deformation (C5), dam foundation seepage (C6).

[0090] Step 2: Quantitative scoring of each indicator Step 2.1, Structural Safety Review (B1) C1 (Anti-slip stability): The standard allows a safety factor of 3.0, but the actual calculated value is 2.92. Positive index linear interpolation: C15 = 2.92 / 3.0 ≈ 0.973 (belonging to 0.95 ≤ C15 < 0.98). score .

[0091] C2 (dam heel and dam site stress): The specification allows a tensile stress of 0.7 MPa, but the actual stress is 0.75 MPa. Inverse index linear interpolation: C11 = 0.75 / 0.7 ≈ 1.071 (belonging to 1.05) <C11≤1.15), score

[0092] C3 (dam body stress): The specification allows a compressive stress of 4.5 MPa, but the actual stress is 4.2 MPa. Inverse index linear interpolation: C11 = 4.2 / 4.5 = 0.93 (belonging to C11 ≤ 1.02) score

[0093] The quantitative scores for each indicator in B1 are as follows: .

[0094] Step 2.2, On-site safety inspection (B2) C4 (Defect Status): Two surface cracks (non-penetrating) with a length of 3-5m were found on site. According to the quantitative analysis standard, this corresponds to "surface cracks that do not affect the integrity" and is scored as 6.5 points.

[0095] The quantitative scores for each indicator in B2 are as follows: .

[0096] Step 2.3, Evaluation of Measured Performance (B3) C5 (Dam Deformation): Monitoring data shows that the annual deformation rate of dam section 4 is 1.0 mm / year (slightly exceeding the elastic weakening index), with a single measuring point score of 7.0; there are no coordinated anomalies in the correlation of multiple measuring points, and the final score is 7.0.

[0097] C6 (Dam Foundation Seepage): The seepage pressure behind the curtain is 25% of the upstream water level (the standard is ≤40%), the seepage flow is stable, and it is scored 9.0 points according to the design indicators.

[0098] The quantitative scores for each indicator in B3 are as follows: .

[0099] Step 3: Weight Determination Process (Analytic Hierarchy Process, AHP) Step 3.1: Calculation of B-level indicator weights

[0100] The importance weights of B1, B2, and B3 to level A need to be determined. The steps are as follows: (1) Constructing the judgment matrix: Compare B1, B2, and B3 pairwise, and score them using the "1-9 scale method". The resulting judgment matrix is ​​as follows ( Table 12 shows the relative importance of Bi to Bj. Table 12 Relative Weights of Level B Sub-item Indicators

[0101] (2) The weights of each indicator are calculated as follows: ① Normalization of each column: The sum of the first column is: 1 + 1 / 4 + 1 / 2 = 1 + 0.25 + 0.5 = 1.75 After normalization: B1 = 1 / 1.75 ≈ 0.571, B2 = 0.25 / 1.75 ≈ 0.143, B3 = 0.5 / 1.75 ≈ 0.286 The sum in column 2 is: 4 + 1 + 3 = 8 After normalization: B1 = 4 / 8 = 0.5, B2 = 1 / 8 = 0.125, B3 = 3 / 8 = 0.375 The sum in column 3 is: 2 + 1 / 3 + 1 ≈ 2 + 0.333 + 1 = 3.333 After normalization: B1 = 2 / 3.333 ≈ 0.6, B2 = 0.333 / 3.333 ≈ 0.1, B3 = 1 / 3.333 ≈ 0.3 ② Sum by row: B1: 0.571 + 0.5 + 0.6 ≈ 1.671 B2: 0.143 + 0.125 + 0.1 ≈ 0.368 B3: 0.286 + 0.375 + 0.3 ≈ 0.961 ③ Normalization: The total sum of all rows = 1.671 + 0.368 + 0.961 ≈ 3.0, therefore: B1 weight = 1.671 / 3 ≈ 0.557 B2 weight = 0.368 / 3 ≈ 0.123 B3 weight = 0.961 / 3 ≈ 0.320

[0102] Weights of each indicator in the B-level sub-tier

[0103] (3) Consistency check: ① Calculate the largest eigenvalue : Matrix multiplication with weight vector (AW):

[0104]

[0105] ② Calculate CI and CR:

[0106] From Table 10, we find that when n=3, RI=0.58. It passed the consistency check.

[0107] The final weights for the B-level indicators are: B1=0.557, B2=0.123, and B3=0.320.

[0108] Step 3.2, Calculation of C-level indicator weights Step 3.2.1: Calculate the weights for C1 (anti-sliding stability), C2 (dam heel stress), and C3 (dam body stress) under B1: (1) Judgment matrix (quantitative analysis), as shown in Table 13: Table 13 Relative Weights of Safety Review Indicators for Class C Structures

[0109] (2) The weights of each indicator are calculated as follows: ① Normalization of each column): The sum of the first column is: 1 + 1 / 3 + 1 / 5 = 1.533 After normalization: C1 = 1 / 1.533 ≈ 0.652, C2 = 0.333 / 1.533 ≈ 0.217, C3 = 0.2 / 1.533 ≈ 0.130 The sum in column 2 is: 3 + 1 + 1 / 2 = 4.5 After normalization: C1 = 3 / 4.5 = 0.667, C2 = 1 / 4.5 = 0.222, C3 = 0.5 / 4.5 = 0.111 The sum of the third column is: 5 + 2 + 1 = 8 After normalization: C1 = 5 / 8 = 0.625, C2 = 2 / 8 = 0.25, C3 = 1 / 8 = 0.125 ② Sum by row: C1: 0.652+0.667+0.625≈1.944 C2: 0.217 + 0.222 + 0.25 ≈ 0.689 C3: 0.130+0.111+0.125≈0.366 ③ Normalization: The total sum of all rows is approximately 1.944 + 0.628 + 0.366 ≈ 3. Therefore: C1 weight = 1.944 / 3 ≈ 0.648 C2 weight = 0.628 / 3 ≈ 0.230 C3 weight = 0.366 / 3 ≈ 0.122

[0110] Weighting of each indicator in the Class C structural safety review .

[0111] (3) Consistency check: ① Calculate the largest eigenvalue : Matrix multiplication with weight vector (AW):

[0112]

[0113] ② Calculate CI and CR:

[0114] From Table 10, we find that when n=3, RI=0.58. It passed the consistency check.

[0115] The final weights for the C-level indicators are: C1=0.648, C2=0.230, and C3=0.122.

[0116] Step 3.2.2: Calculate the weight for C4 (defect condition) under B2: B2 contains only one C-level indicator (C4). According to the logic of the analytic hierarchy process, the relative weight of a single indicator is 1.0 (there is no need to construct a judgment matrix because there are no other indicators to compare).

[0117] C-level on-site safety inspection indicator weighting .

[0118] The weight of C4 relative to B2 is 1.0.

[0119] Step 3.2.3: Calculate the weights for C5 (dam deformation) and C6 (dam foundation seepage) under B3: (1) Judgment matrix (quantitative analysis), as shown in Table 14: Table 14 Relative Weights of C-Level Measured Performance Evaluation Indicators

[0120] (2) Hierarchical single sorting (calculating preliminary weights) ① Normalization of each column: The sum of the first column is: 1 + 1 / 3 = 1.333 After normalization: C5 = 1 / 1.333 ≈ 0.75, C6 = 0.333 / 1.333 ≈ 0.25 The sum in column 2 is 3 + 1 = 4. After normalization: C5 = 3 / 4 = 0.75, C6 = 1 / 4 = 0.25 ② Sum by row: C5: 0.75 + 0.75 = 1.5 C6: 0.25 + 0.25 = 0.5 ③ Normalization: The total sum of all rows = 1.5 + 0.5 = 2, therefore: C5 weight = 1.5 / 2 = 0.75 C6 weight = 0.5 / 2 = 0.25

[0121] Weights of each indicator in the C-level measured performance evaluation .

[0122] (3) Consistency check: ① Calculate the largest eigenvalue : Matrix multiplication with weight vector (AW):

[0123]

[0124] ② Calculate CI and CR:

[0125] Looking up Table 10, we find that RI=0 when n=2. Since the matrix satisfies consistency when n=2, it passes the consistency test.

[0126] The final weights for the C-level indicators are: C5 = 0.75, C6 = 0.25.

[0127] Step 4: Determine the overall security level and grade (1) The evaluation value of the B-level indicator is calculated using formula (3), and the specific calculation process is as follows:

[0128]

[0129]

[0130]

[0131] (2) The comprehensive evaluation value adopts formula (4), and the specific calculation process is as follows:

[0132] Safety level: 7.222 points, which falls within the range of [6, 8), corresponding to level B (relatively safe). It is recommended to address minor defects and strengthen daily monitoring.

[0133] Example 5 In another preferred embodiment, based on embodiments 1 to 4 above, this embodiment provides a comprehensive safety evaluation method for concrete gravity dams, taking a concrete gravity dam in a certain water conservancy project as the object, and combining... Figure 1 The safety comprehensive evaluation process of the evaluation system shown is presented to verify the feasibility and practicality of the method.

[0134] I. Constructing a comprehensive safety evaluation index system in accordance with Figure 1 Based on the "target layer-criteria layer-indicator layer" structure and combined with the characteristics of this gravity dam project, the following evaluation index system is constructed: Target layer (A): The overall safety value of this concrete gravity dam; Criterion layer: includes three indicators: structural safety review, on-site safety inspection, and measured performance evaluation; The indicator layer (C) includes six specific evaluation indicators: structural safety review (including anti-sliding stability, dam heel and toe stress, and internal stress of the dam body); on-site safety inspection (including defect status); and measured performance evaluation (including dam body deformation and dam foundation seepage).

[0135] II. Dimensionless processing and quantitative scoring of each evaluation indicator For the six indicator layers, combined with Figure 1 The quantitative criteria for the indicators are used to calculate the scores using corresponding methods: (i) Quantification using allowable values ​​in specifications (anti-sliding stability, dam heel and toe stress, internal stress of the dam body) 1. Anti-slip stability Structural calculations yielded a sliding stability safety factor of 3.2 under normal water level conditions for the dam. According to water conservancy industry standards, the allowable sliding stability safety factor under this condition is 3.0. Since sliding stability is a positive indicator (a higher value is better), the actual safety factor is divided by the allowable safety factor to obtain the ratio. According to the preset linear interpolation scoring rules (such as...), 10 points Achieve 8-10 points for linear interpolation. (If the score is below 8), the anti-skid stability score is calculated to be 10 points.

[0136] 2. Dam heel and dam toe stress Structural calculations yielded an actual tensile stress of 0.8 MPa at the dam heel, while the allowable tensile stress specified in the code is 1.0 MPa. The stress at the dam heel and toe is an inverse index (lower values ​​are better), and the calculated ratio of the actual stress to the allowable stress is... According to the inverse indicator scoring rules (such as...) 10 points Achieve 8-10 points for linear interpolation. (If the score is below 8), the stress score for the dam heel and toe is 10.

[0137] 3. Internal stress of the dam body The actual compressive stress inside the dam body is 8.5 MPa, while the allowable compressive stress according to the standard is 10 MPa. The calculated ratio is... According to the inverse index scoring rule, the internal stress score of the dam body is 10 points.

[0138] (ii) Quantitative analysis to quantify (defect status) On-site safety inspections were conducted, focusing on the dam surface, foundation, and galleries. The inspection revealed no cracks, leaks, erosion, or other defects in the dam. Based on quantitative analysis standards (10 points for no defects, 6-8 points for minor defects, and below 6 points for serious defects), the average score was taken, resulting in a defect score of 10 points.

[0139] (III) Quantifying using anomaly reasoning (dam deformation, dam foundation seepage) 1. Dam deformation Single-point quantitative analysis: 32 monitoring points (horizontal displacement and settlement displacement) were selected from 8 dam sections. A statistical regression model was established based on monitoring data from the past 5 years, decomposing the water level, temperature, and time-dependent components for each monitoring point. Analysis revealed that the deformation rate at all monitoring points was stable, the time-dependent component tended to converge, and the measured values ​​did not exceed the allowable range specified in the standards. Based on the single-point quantitative criteria, each monitoring point was scored out of 10.

[0140] Single-point multi-effect correlation analysis: By comparing the horizontal displacement and settlement displacement data of each measuring point, the two change patterns match, there are no abnormal correlation signals, and there is no need to adjust the single-point score.

[0141] Multi-point, multi-effect correlation analysis: The data from all dam deformation monitoring points were examined and found to be well-distributed, with displacement differences between adjacent dam sections all within acceptable limits. In summary, the final score for dam deformation is 10 points.

[0142] 2. Dam foundation seepage Single-point quantitative analysis: The monitoring data of 20 piezometers on the dam foundation were analyzed, and a correlation model between seepage pressure and upstream and downstream water levels was established. All piezometer readings were consistent with the trend of water level changes. The piezometer readings behind the curtain were all lower than those in front of the curtain, and the seepage flow rate remained stable for the past 3 years without abnormal fluctuations. Each piezometer reading point was scored out of 10.

[0143] Single-point multi-effect correlation analysis: Correlation of seepage pressure and seepage flow data shows that the variation patterns of the two are matched, indicating that the curtain wall and drainage facilities are operating normally and no score adjustment is required.

[0144] Multi-point, multi-effect correlation analysis: Piezometer readings along the water flow direction showed a gradually decreasing trend, consistent with seepage patterns, with no localized areas of sudden pressure increases. In summary, the final score for dam foundation seepage is 10 points.

[0145] III. Determining Indicator Weights and Verifying Consistency Based on the Analytic Hierarchy Process (AHP) The weights of the criterion layer and the indicator layer are calculated using the analytic hierarchy process (AHP), and a consistency check is performed. (i) Calculation of the weights of criteria-level indicators (weights of structural safety review, on-site safety inspection, and measured performance evaluation on the target level) 1. Constructing the judgment matrix: The relative importance of the three criteria level indicators is compared pairwise using the 1-9 scale method. After summarizing the scoring results, a judgment matrix is ​​constructed.

[0146] 2. Hierarchical Single Sort Normalize each column of the judgment matrix and calculate the normalized value of each column. The row sums of the normalized matrix are obtained to obtain the row sums for structural safety verification, on-site safety inspection, and measured performance evaluation. After normalizing the row sums, the preliminary weights of the criteria layer indicators are obtained: structural safety review ≈ 0.5, on-site safety inspection ≈ 0.2, and measured performance evaluation ≈ 0.3.

[0147] 3. Consistency check Calculate the largest eigenvalue of the judgment matrix According to formula (2), here n=3, CI=0; looking up Table 10, when n=, the average random consistency index RI=0.58, the consistency ratio CR=CI / RI=0<0.1 is calculated, the judgment matrix passes the consistency test, and the final weight of the criteria layer index is (0.5, 0.2, 0.3).

[0148] (II) Calculation of indicator weights at the indicator layer (weights of 6 indicators, including anti-slip stability, to corresponding criteria layer indicators) 1. Weighting of sub-indicators for structural safety review Construct a judgment matrix: Compare the relative importance of anti-sliding stability, dam heel and toe stress, and internal stress of the dam body under the structural safety review in pairs to construct a judgment matrix.

[0149] Hierarchical single sorting and consistency test: After calculation, the weights of anti-sliding stability, dam heel and toe stress, and internal stress of dam body are 0.4, 0.3, and 0.3, respectively, and the judgment matrix passes the consistency test CR<0.1.

[0150] 2. Weighting of Subordinate Indicators for On-site Safety Inspections The on-site safety inspection only includes one indicator: the status of defects, with a weight of 1.0.

[0151] 3. Weights of sub-indicators in the measured performance evaluation Constructing a judgment matrix: The relative importance of dam deformation and dam foundation seepage under the measured performance evaluation is compared pairwise to construct a judgment matrix.

[0152] Hierarchical single sorting and consistency test: After calculation, the weights of dam deformation and dam foundation seepage are 0.5 and 0.5 respectively, and the judgment matrix passes the consistency test CR<0.1.

[0153] IV. Comprehensive Safety Value Calculation and Safety Level Classification (a) Calculation of evaluation values ​​for criteria-level indicators Structural safety review evaluation value: ; On-site safety inspection evaluation value: ; Measured performance evaluation values: .

[0154] (ii) Calculate the comprehensive safety value Overall safety value: .

[0155] (III) Classification of safety levels Using the equal interval division method, the dam's safety level is divided into five levels: A (8-10 points, safe), B (6-8 points, relatively safe), C (4-6 points, generally safe), D (2-4 points, unsafe), and E (0-2 points, extremely unsafe). The dam's comprehensive safety value is 10 points, falling within the [8, 10] interval, corresponding to a safety level of A (safe).

[0156] (iv) Propose countermeasures Given that the dam is classified as Class A and is in a safe condition, it is recommended to maintain the current daily monitoring frequency and conduct a comprehensive safety inspection every six months to ensure the long-term stable operation of the dam.

[0157] In the preferred embodiment, the specific process of quantitative scoring using design indicators in step 2 is as follows: For the evaluation indicators of anti-sliding stability, dam heel and toe stress, and internal dam stress, specific values ​​are obtained through structural calculations, and measured using the allowable values ​​specified in the standards. Anti-sliding stability is a positive indicator, while dam heel and toe stress and internal dam stress are inverse indicators. Linear interpolation is used to quantitatively evaluate the positive and inverse indicators respectively. This setup ensures that each evaluation indicator has a unified standard and scientific basis for quantitative scoring. A larger positive indicator value results in a higher score, while the opposite is true for inverse indicators. After linear interpolation, the influence of each indicator on the overall scheme can be clearly presented, facilitating comprehensive evaluation.

[0158] In the preferred embodiment, the quantitative evaluation process for the positive indicators is as follows: the anti-slip stability safety factor obtained from the structural safety review is divided by the allowable value under the corresponding working condition, and the score of the indicator is calculated according to a linear interpolation formula based on a preset value range. This setup ensures the objectivity and accuracy of the quantitative evaluation of positive indicators. For negative indicators, the opposite logic is used: the allowable value is divided by the actual measured value, and the score is calculated according to the same preset range and linear interpolation formula, thus comprehensively evaluating the structural condition.

[0159] In the preferred embodiment, the quantitative evaluation process of the inverse index is as follows: the stress at the dam heel or toe obtained from the structural safety review or the internal stress of the dam body is divided by the allowable value specified in the standard, and the score of the index is calculated according to the preset value range and the linear interpolation formula. The above settings can ensure the objectivity and accuracy of the quantitative evaluation of the inverse index; the structural stress status can be clearly reflected by comparing the allowable values ​​specified in the standard; the linear interpolation formula makes the scoring transition natural, provides a reliable basis for subsequent comprehensive evaluation, and ensures the scientific nature of the scheme evaluation.

[0160] In the preferred embodiment, the specific process of quantitative scoring through quantitative analysis in step 2 is as follows: for the defects in the dam body and foundation obtained through inspection, quantitative scoring is carried out based on the location, type, and trend of the defects. The above settings can ensure the professionalism and objectivity of the scoring results, and score after comprehensive consideration of different defect factors. This quantitative scoring method provides accurate data for subsequent analysis and processing, which is conducive to accurately assessing the project status and formulating reasonable countermeasures.

[0161] In the preferred embodiment, in step 2, the specific process of using anomaly reasoning for quantitative scoring includes single-test-point quantitative analysis, single-test-point multi-effect correlation analysis, and multi-test-point multi-effect correlation analysis. The above settings enable accurate quantitative evaluation of abnormal data from different dimensions. Single-test-point quantitative analysis focuses on individual test-point characteristics, single-test-point multi-effect correlation analysis explores the correlation of multiple factors within a single test point, and multi-test-point multi-effect correlation analysis takes a holistic view, improving the accuracy and reliability of scoring.

[0162] In the preferred embodiment, in step 2, when using anomaly reasoning to quantify a single measurement point, the score for a single measurement point is the maximum value of the monitoring indicator score and the time-dependent deformation rate score. The final score for a single measurement point is the monitoring indicator score minus the time-dependent deformation rate score. When performing multi-measurement point fusion scoring, the lowest score among all measurement points is taken as the base score for the dam section. After integrating the multi-measurement point judgment rules, the comprehensive score for the dam section is the sum of the base score and the multi-measurement point fusion score. These settings effectively improve the accuracy and comprehensiveness of the assessment. Determining the single measurement point score by taking the maximum value highlights key anomaly indicators; using the lowest score as the base score and integrating multi-measurement point rules comprehensively considers the dam section's condition, providing a reliable basis for engineering safety assessment.

[0163] In the preferred embodiment, the single-point effect analysis model includes a statistical regression model, a correlation analysis model, and a principal component analysis model. For dam deformation, the water level component, temperature component, and time-effect component are obtained through the model, with the time-effect component used as the basis for evaluating the convergence of the measured values. The above settings can effectively improve the accuracy of dam deformation monitoring and accurately separate the components of each influencing factor. By evaluating the convergence of the measured values ​​through the time-effect component, anomalies can be detected in a timely manner, providing reliable data support for the safe and stable operation of the dam and ensuring the safety of the surrounding area.

[0164] In the preferred scheme, the multi-point multi-effect correlation analysis, for dam deformation, it is necessary to determine whether the dam settlement deformation is small and tends to be stable, whether the horizontal deformation of the dam is controlled and trending, and the coordination of deformation values ​​of various parts of the dam, and whether the displacement difference between adjacent dam sections is within the allowable range; for dam foundation seepage, it is necessary to determine the correlation between the piezometer and the upstream and downstream water levels, whether the piezometer readings along the water flow direction gradually decrease, whether the seepage pressure readings behind the curtain are significantly lower than those in front of the curtain, and to jointly analyze the seepage pressure and seepage flow to determine the effectiveness of the curtain and drainage facilities; the above settings can ensure accurate monitoring of the dam body and dam foundation status, and through comprehensive evaluation of multi-dimensional data, potential safety hazards can be detected in a timely manner, providing a reliable basis for the safe operation of the project and ensuring the long-term stability of the dam under complex working conditions.

[0165] In the preferred embodiment, the dam safety level in step 4 is divided into five levels: A, B, C, D, and E. The scoring intervals for each level are determined using an equal interval division method. Each safety level corresponds to a different dam operating state and corresponding countermeasures. Specifically, the scoring interval [8, 10] corresponds to level A, a safe state requiring no special measures; [6, 8) corresponds to level B, a relatively safe state, requiring the resolution of minor defects and enhanced daily monitoring; [4, 6) corresponds to level C, a generally safe state, requiring the development of a special rectification plan and increased monitoring frequency; [2, 4) corresponds to level D, an unsafe state, requiring operational restrictions and the activation of an emergency reinforcement plan; [0, 2) corresponds to level E, an extremely unsafe state, requiring immediate shutdown, reservoir emptying, and emergency repairs. This setup ensures clear and quantitative standards for dam safety assessment, enabling managers to quickly determine the dam's status based on the scoring and take corresponding measures, effectively improving the efficiency and accuracy of dam safety management and ensuring the safe and stable operation of the dam.

[0166] In summary, this invention proposes a comprehensive safety evaluation method for concrete gravity dams, effectively solving specific technical problems in the comprehensive safety evaluation of concrete gravity dams in the field of water conservancy and hydropower engineering. Currently, although the safety monitoring of concrete gravity dams has formed a comprehensive system of multiple monitoring items, safety assessment still mainly relies on qualitative analysis of individual monitoring quantities, lacking a comprehensive consideration and quantitative evaluation of the overall safety status of the dam. This limitation makes it impossible to fully and accurately grasp the safety status of the dam, and it is difficult to meet the high requirements of accuracy and timeliness of safety forecasting and early warning in smart water conservancy construction. Therefore, this invention overcomes the limitations of existing technologies in providing a comprehensive safety evaluation method for concrete gravity dams, which is one-sided, mainly qualitative, and lacks comprehensive consideration.

[0167] This invention proposes a comprehensive safety evaluation method for concrete gravity dams based on multi-source heterogeneous data fusion. It integrates data from structural calculations, inspections, and real-time monitoring, overcoming the limitations of traditional single-monitoring evaluation and achieving full-scale safety status evaluation of the dam. This multi-source data fusion approach is pioneering in the field of concrete gravity dam safety evaluation. Furthermore, this invention employs dimensionless processing technology to quantify each evaluation index within a unified range, solving the problem of inconsistent evaluation methods and data units for different indicators. This processing technology offers a unique approach to the safety evaluation of concrete gravity dams. Finally, this invention scientifically and rationally determines the weights of each evaluation index using the analytic hierarchy process (AHP), avoiding the influence of subjective assumptions and empiricism, resulting in more objective and accurate evaluation results. This weight determination method presents new characteristics in the field of concrete gravity dam safety evaluation.

[0168] This invention not only solves the problem of the one-sided and qualitative analysis-based approach in the safety evaluation of concrete gravity dams in existing technologies, but also achieves a quantitative evaluation of dam safety status through quantitative scoring and weight allocation. This comprehensive quantitative evaluation method has outstanding technical advantages in the field of concrete gravity dam safety evaluation. The hierarchical structure model for gravity dam safety evaluation constructed by this invention comprehensively covers key aspects such as structural safety verification, on-site safety inspection, and measured performance evaluation, realizing a comprehensive consideration of the overall safety status of the dam. The construction of this hierarchical structure model demonstrates a unique concept in the field of concrete gravity dam safety evaluation. The evaluation method of this invention is easy to program and can adapt to the automated analysis needs of intelligent systems, providing strong support for safety management in smart water conservancy construction. This evaluation method combined with intelligent systems exhibits extraordinary characteristics in the field of concrete gravity dam safety evaluation and helps to promote the intelligent development of the water conservancy industry.

Claims

1. A comprehensive safety evaluation method for concrete gravity dams, characterized in that, Includes the following steps: Step 1: Construct a comprehensive safety evaluation index system for concrete gravity dams. The index system includes an objective layer, a criterion layer, and an index layer; the objective layer is the comprehensive safety value of the project. The criteria layer includes structural safety review, on-site safety inspection, and measured performance evaluation; the indicator layer includes anti-sliding stability, dam heel and toe stress, internal stress of the dam body, defect status, dam body deformation, and dam foundation seepage. Step 2: Dimensionless processing and quantitative scoring of each evaluation indicator in the indicator layer. Specific quantification methods include using designed indicators, using anomaly reasoning, and through quantitative analysis. Step 3: Based on the Analytic Hierarchy Process (AHP), obtain the weights of each individual evaluation indicator in the criterion layer and the indicator layer, and perform a consistency test on them; Step 4: Calculate the final comprehensive safety value based on the quantitative scores and corresponding weights of each evaluation indicator, and then classify the dam safety level according to the preset evaluation criteria.

2. The comprehensive safety evaluation method for concrete gravity dams according to claim 1, characterized in that, In step 2, the specific process of using design indicators for quantitative scoring is as follows: For the evaluation indicators of anti-sliding stability, dam heel and toe stress, and internal stress of the dam body, specific values ​​are obtained through structural calculations, and they are measured using the allowable values ​​specified in the code; among them, anti-sliding stability is a positive indicator, and dam heel and toe stress and internal stress of the dam body are inverse indicators. The quantitative evaluation of positive and inverse indicators is achieved by linear interpolation.

3. The comprehensive safety evaluation method for concrete gravity dams according to claim 2, characterized in that, The quantitative evaluation process of the positive index is as follows: divide the anti-slip stability safety factor obtained from the structural safety review by the allowable value under the corresponding working condition, and calculate the score of the index according to the preset value range and the linear interpolation formula.

4. The comprehensive safety evaluation method for concrete gravity dams according to claim 2, characterized in that, The quantitative evaluation process of the inverse index is as follows: divide the dam heel and toe stress or the internal stress of the dam body obtained from the structural safety review by the allowable value in the specification, and calculate the score of the index according to the preset value range and the linear interpolation formula.

5. The comprehensive safety evaluation method for concrete gravity dams according to claim 1, characterized in that, In step 2, the specific process of quantitative scoring through quantitative analysis is as follows: for the defects in the dam body and foundation obtained through inspection, quantitative scoring is carried out using quantitative analysis based on the location, type, and trend of the defects.

6. The comprehensive safety evaluation method for concrete gravity dams according to claim 1, characterized in that: In step 2, the specific process of using anomaly reasoning for quantitative scoring includes single-point quantitative analysis, single-point multi-effect correlation analysis, and multi-point multi-effect correlation analysis. The single-point quantitative analysis involves establishing a single-point effect size analysis model, obtaining the contribution degree of each causal quantity, determining whether there are regular anomalies or unconverged trend changes in the measured values, and realizing single-point quantification based on preset quantification criteria. The single-point multi-effect correlation analysis analyzes the correlation of multi-effects within the same category and different categories, and determines whether the measured changes of multi-effects are consistent, whether the structural problems they reflect are the same, and the trend and consistency of the changes. The multi-point multi-effect correlation analysis is based on single-point quantitative analysis and single-point multi-effect analysis. It analyzes the interrelationship of multiple measurement points in structural space and examines the coordination, differences and trends of the distribution of the measured values ​​of each related measurement point.

7. The comprehensive safety evaluation method for concrete gravity dams according to claim 6, characterized in that: In step 2, when using anomaly reasoning to quantify a single measurement point, the score of a single measurement point is the maximum value of the monitoring index score and the time-dependent deformation rate score. The final score of a single measurement point is the monitoring index score minus the time-dependent deformation score. When merging multiple measurement points for scoring, the lowest score among all measurement points is taken as the base score of the dam section. After merging the multi-measurement point judgment rules, the comprehensive score of the dam section is the sum of the base score and the multi-measurement point fusion score.

8. The comprehensive safety evaluation method for concrete gravity dams according to claim 6, characterized in that: The single-point effect analysis model includes a statistical regression model, a correlation analysis model, and a principal component analysis model. For dam deformation, the water level component, temperature component, and time-effect component are obtained through the model, and the time-effect component is used as the basis for judging the convergence of the measured values.

9. The comprehensive safety evaluation method for concrete gravity dams according to claim 6, characterized in that: In the multi-point multi-effect correlation analysis, for dam deformation, it is necessary to determine whether the dam settlement deformation is small and tends to be stable, whether the horizontal deformation of the dam controls the trend development, and the coordination of the deformation values ​​of various parts of the dam, and whether the displacement difference between adjacent dam sections is within the allowable range; for dam foundation seepage, it is necessary to determine the correlation between the piezometer and the upstream and downstream water levels, whether the piezometer readings along the water flow direction gradually decrease, whether the seepage pressure readings behind the curtain are significantly lower than those in front of the curtain, and to jointly analyze the seepage pressure and seepage flow to determine the effectiveness of the curtain and drainage facilities.

10. The comprehensive safety evaluation method for concrete gravity dams according to claim 1, characterized in that, The specific process of obtaining the weights of each evaluation index based on the analytic hierarchy process and performing consistency checks in step 3 includes: Step 3.1: Construct the judgment matrix: Use the 1-9 scale method to compare and score the indicators at each level pairwise. By collecting, summarizing and generalizing the quantitative analysis results, construct the judgment matrix. Step 3.2, Hierarchical Single Ranking and Consistency Test: Normalize each column of the judgment matrix, sum the rows of the normalized matrix, and normalize the sum again to obtain the eigenvector of the judgment matrix, which is the ranking weight of the relative importance of the indicators at the same level to a certain indicator at the next higher level; calculate the largest eigenvalue of the judgment matrix, calculate the consistency index CI based on the largest eigenvalue, and calculate the consistency ratio CR by combining the average random consistency index RI. When CR < 0.1, the judgment matrix passes the consistency test; otherwise, adjust the judgment matrix and retest. Step 3.3, Overall Hierarchical Ranking: Determine the relative importance ranking of all indicators at a certain level to the evaluation target, following the order from the target level to the criteria level and then to the indicator level, and calculate the weight values ​​of the initial level indicators to the target level.

11. The comprehensive safety evaluation method for concrete gravity dams according to claim 10, characterized in that, In step S3.2, the largest eigenvalue of the judgment matrix is ​​calculated. The formula is: （1）； In the formula, Let be the i-th component of matrix AW. Let be the i-th component of the eigenvector W, n be the order of the judgment matrix, and i be the component index number.

12. The comprehensive safety evaluation method for concrete gravity dams according to claim 10, characterized in that, The formula for calculating the consistency index CI in step 3.2 is as follows: （2）。 13. The comprehensive safety evaluation method for concrete gravity dams according to claim 1, characterized in that, The formulas for calculating the evaluation value of the criterion-level indicators and the comprehensive safety value in step 4 are as follows: Evaluation values ​​of criteria-level indicators: （3）； In the formula, The evaluation value of the criteria layer indicators. The evaluation value of the indicator layer. The weights corresponding to the indicators in the indicator layer; Overall safety value: （4）； In the formula, This is the comprehensive evaluation value for the structural safety of the dam. The evaluation value of the criteria layer indicators. The weights corresponding to the criteria layer indicators.

14. The comprehensive safety evaluation method for concrete gravity dams according to claim 1, characterized in that: In step 4, the dam safety level is divided into 5 levels: A, B, C, D, and E. The scoring interval corresponding to each level is determined by the equal interval division method. Each safety level corresponds to a different dam operation status and corresponding countermeasures.

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