System and method for evaluating safety and health degree of small reservoir dam

Abstract

The invention discloses a safety and health degree evaluation system for a small reservoir dam. The safety and health degree evaluation system comprises an on-site safety inspection module, a safety monitoring data analysis module, a flood prevention capacity rechecking module, a seepage safety evaluation module, a structure safety evaluation module and a dam safety and health degree total rating module. According to the method, comprehensive safety assessment is carried out on the dam by adopting multi-source information, and the uncertainty and subjective influence in the dam service performance assessment and early warning process are reduced.

Description

Technical Field

[0001] The invention relates to the field of model algorithm construction, and in particular to a safety and health evaluation model for a small reservoir dam, and is particularly suitable for safety analysis of a small reservoir dam. Background Art

[0002] At present, 97,000 reservoirs have been built across the country. Among them, small reservoirs account for the vast majority, totaling about 92,000, accounting for as high as 95%. However, due to the large number, wide distribution, inconvenient transportation and other comprehensive factors, small reservoirs have the characteristics of low design standards and insufficient maintenance funds. Accidents and dam breaches of small reservoirs often occur. According to statistics, there are 1,693 dam breaches of small reservoirs with a dam height of less than 15m in my country, which has seriously affected the safety of people's lives and property. In the face of the above situation, the smart water conservancy platform provides an analysis model for the safety of reservoir dams, but most of them are based on statistical models driven by monitoring data. However, in the face of unfavorable conditions such as incomplete monitoring data of small reservoirs and low calibration accuracy of monitoring instruments, a single monitoring data cannot reflect the comprehensive safety of small reservoir dams. Therefore, it is necessary to continue to quantitatively analyze the safety of reservoir dams from the perspective of multi-source information fusion, considering the comprehensive conditions of the dam (basic information, monitoring data, and on-site inspection data). Summary of the invention

[0003] Purpose of the invention: The technical problem to be solved by the present invention is to provide a small reservoir dam safety and health evaluation system in view of the shortcomings of the prior art.

[0004] In order to solve the above technical problems, the present invention discloses a small reservoir dam safety and health evaluation system, including an on-site safety inspection module, a safety monitoring data analysis module, a flood control capacity review module, a seepage safety evaluation module, a structural safety evaluation module and a dam safety and health overall rating module, wherein:

[0005] The on-site safety inspection module is used to grade the on-site inspection situation of the dam. The on-site inspection situation includes the dam crest, dam body, dam abutment, downstream ground and near-dam reservoir bank. The score of this module is obtained by inspecting the above-mentioned parts:

[0006] The safety monitoring data analysis module sets displacement statistical models, pressure tube statistical models and seepage flow models according to different monitoring types, adopts a multi-factor time-varying model, and establishes a statistical model between external loads and effect values, thereby obtaining the effect value under the current load condition; and uses the confidence interval estimation method to establish a grading index based on the obtained effect value to obtain the score of the module;

[0007] The flood control capacity review module evaluates the flood control capacity of the dam by comparing the change of the current water level caused by different inflows with the dam crest elevation, and obtains a corresponding flood control capacity score;

[0008] The seepage safety evaluation module evaluates the hydraulic gradient and leakage based on the basic information of the dam and the monitoring data, and obtains the score of the seepage safety evaluation module;

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

[0010] The dam safety and health overall rating module provides an overall rating for the dam safety and health based on the scores of the on-site safety inspection module, the safety monitoring data analysis module, the flood control capacity review module, the seepage safety evaluation module, and the structural safety evaluation module.

[0011] Specifically, the on-site safety inspection module obtains the dam evaluation scoring table after necessary simplification based on the "Guidelines for Safety Evaluation of Reservoir Dams" (SL 258-2017) and taking into account the characteristics of small reservoirs:

[0012]

[0013]

[0014] Each item in the above table has three evaluation levels, each with a corresponding rating score, which are: A: 100; B: 50; C: 0; the total score for the on-site safety inspection module is:

[0015] F1=avg(f 1,j )(1)

[0016] Among them, f 1,j is the jth on-site safety rating score, avg(·) is the average of ·, where when the on-site inspection of any part is graded C, the dam is rated as high risk.

[0017] The on-site safety inspection module can be divided into the following categories according to the score F1: fourth class (0, 25], third class (25, 50], second class (50, 75], and first class (75, 100].

[0018] The displacement statistical model during the dam operation period is shown in formula (2), from which the displacement effect value can be obtained:

[0019]

[0020] Where: is the constant regression coefficient (displacement model); is the water level related regression coefficient (displacement model); is the regression coefficient of time effect (displacement model); is the corresponding water level of the upstream and downstream reservoirs on the monitoring day of the i-th day; t is the calculation starting time, θ = t / 100;

[0021] The statistical model of the piezometer of earth-rock dam is shown in formula (3), from which the effect value of seepage pressure can be obtained:

[0022]

[0023] Where: is the constant regression coefficient (pressure pipe model); is the mean water level correlation regression coefficient (pressure pipe model); is the regression coefficient of rainfall (pressure pipe model); is the time effect regression coefficient (pressure pipe model). is the average upstream water level in the previous i days; is the average rainfall in the previous i days;

[0024] The seepage model of earth-rock dam adopts formula (4), and the effect value of seepage can be obtained:

[0025]

[0026] Where: is the constant regression coefficient (seepage model); is the water level related regression coefficient (seepage model); is the mean water level correlation regression coefficient (seepage model); is the rainfall regression coefficient (seepage model); is the time effect regression coefficient (seepage model);

[0027] According to the observation data and environmental variables, a statistical mathematical model (Formula 2-4) is established to obtain different types of effect values. and its confidence interval with Δ ty :

[0028] Δ ty = ±βS ty (5) Where: ty = d, h, q; S ty is the standard deviation of the statistical model; β is a function of the significance level α, where α=1%, β=2.576; α=5%, β=1.96; if the measured value is within Δ ty If the dam is within the range, it is considered that the dam is operating safely; otherwise, it may be abnormal. Therefore, the control index of the monitoring quantity It can be written as:

[0029]

[0030] Then the measured value is compared with the control index interval to obtain the safety monitoring data rating score f 2j They are: 100, 50, 0 respectively; then, the total score of the safety monitoring data analysis module is:

[0031] F2=avg(f 2j )(7)

[0032] The safety monitoring data analysis module can be divided into the following categories according to the score F2: fourth class (0, 25], third class (25, 50], second class (50, 75], and first class (75, 100].

[0033] The flood control capacity review module obtains the flood control capacity score by the following method. y It can be solved by iteratively using the water balance equation. The specific formula is as follows:

[0034]

[0035] Where: A s is the reservoir surface area; s is the reservoir water level; t is time; Q in is the inflow flow; Q spill is the outflow of the spillway; Q sluice is the gate outflow;

[0036] The corresponding predicted water level h can be obtained through the water balance equation y , based on the actual engineering data, the dam top elevation h d and the initial water level h0, the corresponding flood control capacity score can be obtained:

[0037]

[0038] The flood control capacity review module can be divided into the following categories according to the score F3: fourth class (0, 25], third class (25, 50], second class (50, 75], and first class (75, 100].

[0039] The critical hydraulic gradient adopts the piping type with the highest risk factor. The allowable hydraulic gradient J can be calculated using formula (10): 允许 , its expression:

[0040]

[0041] Where: K is the permeability coefficient of the soil; d3 is the soil particle size corresponding to the soil weight being less than 3% of the total weight; n is the porosity. Hydraulic drop threshold J CThe threshold coefficient (C) can be used to adjust the allowable hydraulic gradient to obtain the secondary control index, which is as follows:

[0042] J c =CJ 允许 (11) Where: J C is the C-level hydraulic gradient threshold; C is the threshold coefficient, which is 0.8 and 1.2 respectively, and can be adjusted according to the importance of hydraulic structures; the seepage safety rating score (f 4,j ):100,50,0;

[0043] For leakage, the allowable leakage q 允许 It can be obtained based on the upstream and downstream water levels and dam geometric conditions. The specific expression is as follows:

[0044]

[0045] In the formula, H1 is the upstream water level elevation; H2 is the downstream water level elevation; L is the horizontal distance between the upstream and downstream water levels, such as Figure 3 As shown. Leakage threshold q C The threshold coefficient (C) can be used to adjust the allowable hydraulic gradient to obtain the secondary control index, which is as follows:

[0046] q C =Cq 允许 (13) Where: q C is the C-level seepage threshold, C is the threshold coefficient, which is 0.8 and 1.2 respectively, and can be adjusted according to the importance of hydraulic structures; by comparing the j-th monitored seepage volume with the control index interval range, the seepage safety rating score (f 4,j ):100,50,0.

[0047] By summarizing the hydraulic gradient and seepage rating scores, the score of the seepage safety evaluation module can be calculated by the following formula:

[0048] F4=avg(f 4,j )(14)

[0049] The rating of the seepage safety evaluation module can be divided into the following categories according to the score F4: fourth class (0, 25], third class (25, 50], second class (50, 75], and first class (75, 100].

[0050] The maximum dam height (H max ) as the secondary control index, and the safety of the deformed structure is discussed in a graded manner. Then the control index D C According to the following formula:

[0051] D C=CH max (15) Where: H max is the maximum dam height, C is the threshold coefficient, which is 0.01 and 0.03 respectively. By comparing the jth monitored settlement displacement with the control index range, the corresponding structural safety rating score (f 5,j ):100,50,0;

[0052] According to the "Slope Design Code for Water Conservancy and Hydropower Engineering" (SL386-2007), the two-level control index of stability and structural safety (S C ) can be determined by the following formula:

[0053] S C =CS 允许 (16) Where: Allowable safety factor S 允许 is 1.1, C is the threshold coefficient, which is 1.0 and 1.2 respectively. By comparing the calculated safety factor S with the control index range, the corresponding structural safety rating score (f 5,j ): 100, 50, 0. The safety factor is determined by the Swedish strip method. When the geotechnical structure is discretized into m soil strips for analysis, according to the limit equilibrium state principle, the sliding moment = anti-sliding moment, and the safety factor S is:

[0054]

[0055] Where: c m , W m are the cohesion, internal friction angle and weight of the mth soil block, respectively, l m ,θ m are the length and horizontal angle of the sliding surface where the mth soil block is located respectively.

[0056] By summing up the deformation and stability structural safety rating scores, it can be calculated by the following formula:

[0057] F5=avg(f 5,j (18) The sub-module ratings can be divided into the following categories based on the score F5: fourth class (0, 25], third class (25, 50], second class (50, 75], and first class (75, 100].

[0058] The total score of dam safety and health is expressed as:

[0059]

[0060] in, is the overall score of the dam; F UScore the Uth submodule, U = 1, 2, 3, 4, 5, corresponding to the on-site safety inspection module, safety monitoring data analysis module, flood control capacity review module, seepage safety evaluation module and structural safety evaluation module respectively; Q U is the weight coefficient of the Uth submodule. The overall rating of the dam can be divided into the following categories: low risk (0, 25], medium risk (25, 50], relatively high risk (50, 75], and high risk (75, 100]; the weight coefficient range is [0, 1].

[0061] The present invention also provides a method for evaluating the safety and health of a small reservoir dam using the above-mentioned small reservoir dam safety and health evaluation system, comprising the following steps:

[0062] (1) Basic data summary: The basic data of the dam is obtained through the basic information of the dam, test data and on-site inspection data. The basic information of the dam includes dam height, upstream and downstream slope ratio, dam top width, dam bottom width, cohesion of dam materials, internal friction angle of dam materials, permeability coefficient of dam materials, reservoir capacity curve and discharge curve; the monitoring data includes displacement monitoring data and its relative position, pressure measuring tube monitoring data and its relative position, seepage flow monitoring data and its relative position, upstream and downstream water levels, rainfall, temperature and inflow;

[0063] (2) The corresponding scores F are calculated in parallel for the on-site safety inspection module, safety detection data analysis module, flood control capacity review module, seepage safety module and structural safety evaluation module. I The scoring is divided into four intervals based on the percentage system: (75, 100], (50, 75], (25, 50], (0, 25], and the rating of each sub-item is determined accordingly: first class, second class, third class, fourth class;

[0064] (3) The total score of dam safety and health is calculated based on the scores of each module and expressed as:

[0065]

[0066] in, is the overall score of the dam; F U Score the Uth submodule, U = 1, 2, 3, 4, 5, corresponding to the on-site safety inspection module, safety monitoring data analysis module, flood control capacity review module, seepage safety evaluation module and structural safety evaluation module respectively; Q U is the weight coefficient of the Uth submodule. The overall rating of the dam can be divided into the following categories: low risk (0, 25], medium risk (25, 50], relatively high risk (50, 75], and high risk (75, 100]; the weight coefficient range is [0, 1].

[0067] Beneficial effects: Due to historical reasons left over from small reservoirs, their basic information, monitoring data and operation management levels are generally low. In the past, single evaluation systems often failed to truly reflect the actual operating status of reservoirs due to data loss. In this context, the present invention considers the comprehensive operating conditions of small reservoirs, and proposes a safety and health evaluation model for small reservoir dams based on on-site safety inspections and monitoring data analysis. According to the basic framework of the "Guidelines for Safety Evaluation of Reservoir Dams", the safety and health evaluation model for small reservoir dams is divided into five modules: 1. On-site safety inspection; 2. Safety monitoring data analysis; 3. Flood control capacity review; 4. Seepage safety evaluation; 5. Structural safety evaluation. According to on-site inspections, monitoring data, dam material properties, and measured data of environmental quantities such as reservoir water level, rainfall, and temperature, the parameter completeness conditions are analyzed. Thus, based on on-site safety inspections and monitoring data, a multi-scenario, multi-output dam safety and health evaluation model suitable for small reservoirs is established. The model emphasizes the complementarity and integration of multi-source information from the perspective of the fusion of similar and heterogeneous multi-source information, comprehensively evaluates the health of the dam, and reduces the uncertainty and subjective influence in the process of dam service performance assessment and early warning. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 This is the system framework diagram of the small reservoir dam safety and health evaluation model;

[0069] Figure 2 It is a geometric diagram of a small reservoir dam;

[0070] Figure 3 This is a schematic diagram of leakage threshold calculation;

[0071] Figure 4 Schematic diagram of sliding torque calculation. DETAILED DESCRIPTION

[0072] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0073] This application uses multi-source information to conduct a comprehensive safety assessment of the dam, reducing the uncertainty and subjective influence in the dam service performance assessment and early warning process.

[0074] Specifically, the present application provides a small reservoir dam safety and health evaluation system, including an on-site safety inspection module, a safety monitoring data analysis module, a flood control capacity review module, a seepage safety evaluation module, a structural safety evaluation module and a dam safety and health overall rating module. Figure 1 shown.

[0075] Among them, the safety monitoring data analysis module sets up displacement statistical models, pressure tube statistical models and seepage flow models according to different monitoring types, adopts a multi-factor time-varying model, and establishes a statistical model between external loads and effect values, thereby obtaining the effect value under the current load condition; and uses the confidence interval estimation method to establish a grading index based on the obtained effect value to obtain the score of the module;

[0076] The flood control capacity review module evaluates the flood control capacity of the dam by comparing the change in current water level caused by different inflows with the dam crest elevation and obtains the corresponding flood control capacity score;

[0077] The seepage safety evaluation module evaluates the hydraulic gradient and seepage based on the basic information of the dam and monitoring data, and obtains the score of the seepage safety evaluation module;

[0078] The structural safety evaluation module calculates the score of the structural safety evaluation module through two aspects: deformation control and safety factor stability analysis;

[0079] The dam safety and health overall rating module gives an overall rating of the dam safety and health based on the scores of the on-site safety inspection module, safety monitoring data analysis module, flood control capacity review module, seepage safety evaluation module, and structural safety evaluation module.

[0080] The scoring method for each module is described in detail below.

[0081] The basic data of the dam are obtained based on the basic information of the dam, test data and on-site inspection data. The basic information of the dam includes dam height, upstream and downstream slope ratio, dam top width, dam bottom width, cohesion of dam construction materials, internal friction angle of dam construction materials, permeability coefficient of dam construction materials, reservoir capacity curve and discharge curve; the monitoring data include Boake displacement monitoring data and its relative position, pressure measuring tube monitoring data and its relative position, seepage flow monitoring data and its relative position, upstream and downstream water levels, rainfall, temperature and inflow flow.

[0082] (I) On-site safety inspection module (Module 1):

[0083] On-site inspection is an important part of evaluating the health of small reservoirs. Analyze the inspection data of previous inspections, and make qualitative judgments based on the abnormal appearance of the dam and its location, changing patterns and development trends. In order to achieve comprehensive quantitative analysis, it is necessary to assign points to the inspection content and give a certain evaluation to the previous inspection tasks. According to the "Guidelines for Safety Evaluation of Reservoir Dams" (SL258-2017), for small and medium-sized reservoirs, the present invention assigns points to the on-site safety of the dam according to Table 1:

[0084] Table 1 Dam site scoring table

[0085]

[0086]

[0087] Each item in the above table has three evaluation levels, each with corresponding points, where A: 100; B: 50; C: 0; the total score for the on-site safety inspection module is:

[0088] F1=avg(f 1,j )(1)

[0089] Among them, f 1,j is the jth on-site safety rating score, avg(·) is the average of ·, where when the on-site inspection of any part is graded C, the dam is rated as high risk.

[0090] The module rating can be divided into the following categories according to the score F1: fourth class (0, 25], third class (25, 50], second class (50, 75], and first class (75, 100].

[0091] (II) Safety monitoring data analysis module (Module 2)

[0092] For small reservoirs, this paper adopts the multi-factor time-varying model in the "Hydraulic Design Manual - Hydraulic Safety Monitoring" to establish a statistical model between external loads and effect values, so as to obtain the effect value under the current load conditions. The confidence interval is used to perform error analysis on the monitoring data, and the standard deviation coefficient is adjusted to determine the corresponding multi-level threshold. According to the different types of monitoring data, it can be divided into three sub-items: displacement, seepage pressure, and seepage:

[0093] a) Displacement statistical model. It mainly considers the operation period of the dam. The displacement of the earth-rock dam is mainly caused by consolidation and is also affected by reservoir water level and temperature. The settlement caused by consolidation also reflects the characteristics of time effect. The statistical model of settlement during operation is:

[0094]

[0095] Where: is the constant regression coefficient (displacement model); is the water level related regression coefficient (displacement model); is the time effect regression coefficient (displacement model). is the corresponding water level of the upstream and downstream reservoirs on the i-th monitoring day; t is the calculation starting time, θ = t / 100.

[0096] b) Piezometer statistical model. The main influencing factors can be divided into upstream water level component, downstream water level component, rainfall component, and time component. Considering comprehensive factors, the piezometer statistical model of earth-rock dam is written as:

[0097]

[0098] Where: is the constant regression coefficient (pressure pipe model); is the mean water level correlation regression coefficient (pressure pipe model); is the regression coefficient of rainfall (pressure pipe model); is the time effect regression coefficient (pressure pipe model). is the average upstream water level in the previous i days; is the average rainfall in the previous i days.

[0099] c) Seepage model. It is mainly affected by the upstream and downstream water depth, rainfall infiltration, and the time-varying process of siltation and impermeable body in front of the dam. Since the material properties of earth-rock dams change little with temperature, the temperature sub-item can generally be partially considered. In summary, the statistical model of earth-rock dam seepage is:

[0100]

[0101] Where: is the constant regression coefficient (seepage model); is the water level related regression coefficient (seepage model); is the mean water level correlation regression coefficient (seepage model); is the rainfall regression coefficient (seepage model); is the time effect regression coefficient (seepage model).

[0102] d) Comprehensive evaluation of safety monitoring data. Based on the observation data, a statistical mathematical model (Formula 2 to 4) is established, and different types of calculated values ​​are used to calculate the and its confidence interval with Δ ty :

[0103] Δ ty = ±βS (5)

[0104] Where: S is the standard deviation of the statistical model; β is a function of the significance level α (α = 1%, β = 2.576; α = 5%, β = 1.96). ty If the dam is within the specified range, it is considered that the dam is operating safely. Otherwise, it may be abnormal. Therefore, the control index of the monitoring quantity can be written as:

[0105]

[0106] Then the measured value is compared with the control index range to obtain the safety monitoring data rating score (f 2j ) are 100, 50, and 0 respectively. Then, the total score of the safety monitoring data analysis module is:

[0107] F2=avg(f 2j)(7)

[0108] The submodule ratings can be divided into the following categories based on the score F2: fourth class (0, 25], third class (25, 50], second class (50, 75], and first class (75, 100].

[0109] (III) Flood control capacity evaluation module (Module 3)

[0110] The flood control capacity considers the changes in the current water level caused by different inflows and compares it with the dam crest elevation to evaluate the flood control capacity of the dam. The current water level is a dynamic process, including the inflow of the upstream river and the discharge capacity of the downstream. When calculating the change in the upstream reservoir water elevation, it is necessary to consider the inflow, spillway and gate discharge at the same time. The whole process obeys the water balance equation:

[0111]

[0112] Where: A s is the reservoir surface area; s is the reservoir water level; t is time; Q in is the inflow flow; Q spill is the outflow of the spillway; Q sluice is the gate outflow;

[0113] The corresponding predicted water level h can be obtained through the water balance equation y , and the dam crest elevation h d and the initial water level h0, the corresponding flood control capacity score can be obtained:

[0114]

[0115] The module three rating can be divided into four categories according to the score F3: fourth class (0, 25], third class (25, 50], second class (50, 75], first class (75, 100], and the corresponding computational geometry diagram is as follows Figure 2 shown.

[0116] (IV) Seepage safety assessment module (Module 4)

[0117] This module evaluates the dam's basic information and monitoring data to determine the dam's seepage safety, which is divided into two aspects: hydraulic gradient and leakage.

[0118] a) For hydraulic gradient, the present invention calculates hydraulic gradient based on seepage pressure monitoring data and relative position, and obtains corresponding seepage stability score by comparing with multi-level hydraulic gradient thresholds, wherein the calculation method of allowable hydraulic gradient is derived from the "Specifications for Geological Survey of Hydropower and Hydropower Engineering". The critical hydraulic gradient adopts the pipe burst type with the highest risk factor, and its expression is:

[0119]

[0120] Where: K is the permeability coefficient of the soil; d3 is the particle size of the soil corresponding to the soil weight being less than 3% of the total weight; n is the porosity;

[0121] The hydraulic gradient is allowed to pass through the threshold coefficient (C) to obtain a two-level control index, which is divided into three intervals:

[0122] J C =CJ 允许 (11) Where: J C is the C-level hydraulic gradient threshold; C is the threshold coefficient, which is 0.8 and 1.2 respectively, and can be adjusted according to the importance of hydraulic structures; the seepage safety rating score (f 4,j ):100,50,0.

[0123] b) For leakage, the present invention uses the corresponding leakage threshold to evaluate the safety of the seepage monitoring data. According to the "Specifications for Geological Survey of Water Conservancy and Hydropower Engineering", the basic leakage calculation value can be expressed as:

[0124]

[0125] In the formula, H1 is the upstream water level elevation; H2 is the downstream water level elevation; L is the horizontal distance between the upstream and downstream water levels, such as Figure 3 shown.

[0126] According to the different upstream and downstream water level heights, the allowable leakage threshold q is calculated. 允许 , the multi-level control index can be obtained according to the following formula:

[0127] q C =Cq 允许 (13) Where: q C is the C-level seepage threshold, C is the threshold coefficient, which is 0.8 and 1.2 respectively, and can be adjusted according to the importance of hydraulic structures; by comparing the j-th monitored seepage volume with the control index interval range, the seepage safety rating score (f 4,j ):100,50,0.

[0128] c) For the comprehensive evaluation of seepage safety, the total score of this module 4 is, which can be calculated by summarizing the hydraulic gradient and seepage volume using the following formula:

[0129] F4=avg(f 4,j )(14)

[0130] The submodule ratings can be divided into the following categories according to the score F4: fourth class (0, 25], third class (25, 50], second class (50, 75], and first class (75, 100].

[0131] (V) Structural safety module (Module 5)

[0132] The structural safety module of the present invention has two sub-items: 1. deformation structure safety analysis, 2. stability structure safety analysis.

[0133] a) Safety analysis of deformation structure mainly refers to the "Design Code for Roller Compacted Earth-Rock Dams" (SL274-2001), which stipulates that "the settlement of the dam crest after completion should not be greater than 1% of the dam height". Years of engineering practice experience have shown that if the settlement after completion is less than 1% of the dam height, there will generally be no obvious cracks, while if it is greater than 1% to 3%, there is a greater possibility of cracks. Based on this, the maximum dam height (H max ) is used as the secondary control index to discuss the safety of the deformed structure in a graded manner. Then the control index D C According to the following formula:

[0134] D C =CH max (15) Where: H max is the maximum dam height, C is the threshold coefficient, which is 0.01 and 0.03 respectively. By comparing the jth monitored settlement displacement with the control index range, the corresponding structural safety rating score (f 5,j ):100,50,0.

[0135] b) Stability structure safety analysis: According to the "Code for Slope Design of Water Conservancy and Hydropower Engineering" (SL386-2007), the control index of stability structure safety (S C ) can be determined by the following formula:

[0136] S C =CS 允许 (16) Where: S 允许 is 1.1, C is the threshold coefficient, which is 1.0 and 1.2 respectively. By comparing the calculated safety factor S with the control index range, the corresponding structural safety rating score (f 5,j ): 100, 50, 0. The safety factor can be determined by the Swedish strip method. When the geotechnical structure is discretized into m soil strips for analysis, according to the limit equilibrium state principle, the sliding moment = anti-sliding moment, the safety factor S is:

[0137]

[0138] Where: c m , W m are the cohesion, internal friction angle and weight of the mth soil block, respectively, l m ,θ m are the length and horizontal angle of the sliding surface where the mth soil block is located respectively.

[0139] 3) For the comprehensive evaluation of structural safety, the total score of module 5 summarizes the deformation and stability structural safety rating scores and can be calculated by the following formula:

[0140] F5=avg(f 5,j (18) The sub-module ratings can be divided into the following categories based on the score F5: fourth class (0, 25], third class (25, 50], second class (50, 75], and first class (75, 100].

[0141] (VI) Overall evaluation of reservoir dam safety and health (Module 5)

[0142] The total rating of reservoir dams is divided into four levels: low risk, medium risk, relatively high risk, and high risk. The submodule scores are divided into four levels: first, second, third, and fourth (good → poor), where the scores for each submodule are 25, 50, 75, and 100 respectively. Then the total score of the dam is expressed as:

[0143]

[0144] in, is the overall score of the dam; F U Score the Uth submodule, U = 1, 2, 3, 4, 5, corresponding to the on-site safety inspection module, safety monitoring data analysis module, flood control capacity review module, seepage safety evaluation module and structural safety evaluation module respectively; Q U is the weight coefficient of the Uth submodule. The overall rating of the dam can be divided into the following categories: low risk (0, 25], medium risk (25, 50], relatively high risk (50, 75], and high risk (75, 100]; the weight coefficient range is [0, 1].

[0145] Application Examples

[0146] A homogeneous dam is located in Hunan Province. The dam is 46.30 m high and 210.00 m long along the dam axis. Observation stations are set up on the dam top and downstream. The monitoring data from 2020 to 2022 are selected, and the evaluation system proposed in the present invention is used to evaluate and analyze the safety and health of the dam. The evaluation system is divided into on-site safety inspection module, safety monitoring data analysis module, flood control capacity review module, seepage safety evaluation module, structural safety evaluation module and dam safety and health overall rating module.

[0147] (1) On-site safety inspection module

[0148] According to the "Guidelines for Safety Assessment of Reservoir Dams" and combined with the characteristics of small reservoirs, an on-site inspection form is set up. On-site inspectors use mobile phone APP to assign points to analyze the real-time safety situation of the dam site, as shown in the table below. According to the calculation results of the on-site safety inspection (module one), it can be concluded that the dam is in a safe operating state. According to formula (1), the corresponding module total (F1) score is 100.

[0149] Table 2 Calculation results of on-site safety inspection (module 1)

[0150]

[0151] (2) Safety monitoring data analysis module

[0152] 1) Displacement monitoring model:

[0153] Based on the settlement monitoring data of the four dam sections from 2020 to 2022, the displacement statistical model is obtained through the stepwise regression algorithm based on formula (2):

[0154]

[0155] S d =1.715(21)

[0156] The two-level confidence interval bands can be obtained from the significance level:

[0157]

[0158] Based on the environmental variables: upstream water level (H1) 41.0 m, downstream water level (H2) 1.21 m, monitoring time (t) 213 days, the calculated settlement is obtained by formula (20): is 10.75mm. According to formula (6), the two-level index can be obtained The score is: [7.39, 14.11], [5.69, 15.81]. According to the measured monitoring data 15.10 mm is between the first-level index and the second-level index, the score (f 2,1 ) is 50, see the table below for details.

[0159] Table 3 Calculation results of settlement data

[0160]

[0161] 2) Osmotic pressure monitoring model:

[0162] Based on the seepage pressure monitoring data of hole No. 1 from 2020 to 2022, the seepage pressure statistical model was obtained through the stepwise regression algorithm based on formula (3):

[0163]

[0164] S h=0.82(24)

[0165] The two-level confidence interval bands can be obtained from the significance level:

[0166]

[0167] Environmental variables: 1-day average upstream water level 5-day average upstream water level Average rainfall per day 3-day average rainfall The monitoring time (t) is 213 days, and the calculated osmotic pressure value is obtained by formula (23): is 30.08m. According to formula (6), the two-level index can be obtained The actual monitoring data is 33.1m, which exceeds the level 2 index. The score (f 2,2 ) is 0, see the table below for details.

[0168] Table 4 Calculation results of osmotic pressure data

[0169]

[0170] 3) Seepage monitoring model:

[0171] Based on the seepage monitoring data from 2020 to 2022, the seepage statistical model is obtained through the stepwise regression algorithm based on formula (4):

[0172]

[0173] S q =3.85(27)

[0174] The two-level confidence interval bands can be obtained from the significance level:

[0175]

[0176] Environmental variables: upstream water level (H1) 41.0m, 1-day average upstream water level 13-day average upstream water level 14-day upstream average water level Average rainfall per day mm, 2-day average rainfall The calculated seepage rate is obtained by formula (26): is 44.01 mL / s. According to formula (6), the two-level index can be obtained The actual monitoring data of 52.11 mL / s is between the first-level index and the second-level index. The score (f 2,3) is 50, see the table below for details.

[0177] Table 5 Calculation results of seepage data

[0178]

[0179]

[0180] 4) Overall score of safety monitoring data:

[0181] Based on three different statistical models of displacement, seepage and seepage pressure, the total score (F2) of the safety monitoring data analysis module can be obtained according to formula (7), as shown in the following table.

[0182] Table 6 Calculation results of safety monitoring data analysis (module 2)

[0183]

[0184] (3) Flood control capacity review module

[0185] According to the basic data of the reservoir in this example (reservoir capacity curve, flood discharge curve), the predicted water level can be obtained based on the water balance equation (Formula 8). The upstream reservoir water level of the example reservoir is 35.0m, the dam top elevation is 46.30m, and the inflow is obtained from the hydrological data, as shown in the following table

[0186] Table 7 Inflow

[0187]

[0188]

[0189] The predicted water level (h y ) is 37.6m, then the flood control capacity score (F3) can be obtained as 77.00 according to formula (9). The specific calculation results are shown in the table below.

[0190] Table 8 Calculation results of flood control capacity review and evaluation (module 3)

[0191] <![CDATA[Crest elevation (h d )]]> <![CDATA[Forecast water level (h y )]]> <![CDATA[Initial water level (h0)]]> Overall rating Module Rating 46.30m 37.6m 35.0m 77.00 Second Class

[0192] (4) Seepage safety assessment module

[0193] 1) Hydraulic gradient safety evaluation

[0194] The reservoir dam in this example is a homogeneous dam with a permeability coefficient K of 1X10 -3 cm / s, the soil particle size (d3) corresponding to less than 3% of the total weight is 0.02 mm, and the porosity (n) is 0.21. According to formula (10), the allowable hydraulic gradient (J 允许 ) is 3.84. The two-level control index of hydraulic drop is obtained from the threshold coefficient:

[0195]

[0196] The test hydraulic gradient is obtained from the maximum section seepage pressure monitoring data and the corresponding coordinates: 2.2 and 3.3. From the control indicators, it can be seen that the hydraulic gradient scores (f4,1, f4,2) are 100 and 50 respectively.

[0197] 2) Safety evaluation of leakage

[0198] In this example, the upstream water level (H1) is 35.1m, the downstream water level (H2) is 1.2m, the upstream and downstream horizontal distance is 81.0m, and the permeability coefficient K is 1X10 -3 cm / s, according to formula (12), the allowable leakage (q 允许 ) is 75.0mL / s.

[0199] The two-level control index of leakage volume is obtained by the threshold coefficient:

[0200]

[0201] The actual leakage data at the site show that the seepage rates at the two locations are 52.11 mL / s and 43.12 mL / s respectively. The control index shows that the leakage rate score (f 4,3 ,f 4,4 ) are 100 and 100 respectively.

[0202] 3) Total score of seepage safety evaluation module:

[0203] According to the safety evaluation of hydraulic gradient and leakage, the total score (F4) of the seepage safety module is 87.5, which is rated as first class. See the table below for details.

[0204] Table 9 Calculation results of seepage safety assessment (module 4)

[0205]

[0206] (5) Structural safety assessment module

[0207] 1) Safety analysis of deformation structures

[0208] The maximum dam height (H max ) is 46.30m, and the settlement deformation control index can be obtained from formula (15):

[0209]

[0210] The actual settlement monitoring data of A and B on site are 0.235m and 0.514m respectively. The safety score of the deformed structure (f 5,1 ,f5,2 ) are 100 and 50 respectively.

[0211] 2) Stability and structural safety analysis

[0212] According to the "Code for Slope Design of Water Conservancy and Hydropower Projects", the allowable safety factor (S 允许 ) is taken as 1.1, and the stability control index can be obtained by formula (16):

[0213]

[0214] The density of the known reservoir dam material is 2.3g / cm 3 , cohesion is 4.23 kPa, internal friction angle is 27.8°, and there are 200 soil strips in total. According to formula (17), the most dangerous safety factor is 1.9. The settlement deformation score (f 5,3 ) are 100 respectively.

[0215] 3) Total score of structural safety evaluation module

[0216] According to the deformation and stability structural safety analysis, the total score of the structural safety module (F5) is 83.33, which is rated as first class. See the table below for details.

[0217] Table 10 Calculation results of structural safety module (module five)

[0218]

[0219] (5) Safety and health of reservoir dams

[0220] According to the comprehensive scores of the five sub-modules, namely, on-site safety inspection module, safety monitoring data analysis module, flood control capacity review module, seepage safety evaluation module and structural safety evaluation module, the overall health of the dam is obtained as 76.34 using the average scoring method (Formula 19), as shown in the table below for details.

[0221] Table 11 Dam safety and health calculation results

[0222]

[0223]

[0224] The present invention provides a small reservoir dam safety and health evaluation system. There are many methods and ways to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A small reservoir dam safety and health evaluation system, characterized in that: It includes on-site safety inspection module, safety monitoring data analysis module, flood control capacity review module, seepage safety evaluation module, structural safety evaluation module and dam safety health rating module, among which: The on-site safety inspection module is used to grade the on-site inspection situation of the dam, including the dam crest, dam body, dam abutment, downstream ground and near-dam reservoir bank. The score of this module is obtained by inspecting the above-mentioned parts; The safety monitoring data analysis module sets displacement statistical models, pressure tube statistical models and seepage flow models according to different monitoring types, adopts a multi-factor time-varying model, and establishes a statistical model between external loads and effect values, thereby obtaining the effect value under the current load condition; and uses the confidence interval estimation method to establish a grading index based on the obtained effect value to obtain the score of the module; The flood control capacity review module evaluates the flood control capacity of the dam by comparing the change of the current water level caused by different inflows with the dam crest elevation, and obtains a corresponding flood control capacity score; The seepage safety evaluation module evaluates the hydraulic gradient and leakage based on the basic information of the dam and the monitoring data, and obtains the score of the seepage safety evaluation module; The structural safety evaluation module calculates the score of the structural safety evaluation module through deformation control and safety factor stability analysis; The dam safety and health overall rating module provides an overall rating for the dam safety and health based on the scores of the on-site safety inspection module, the safety monitoring data analysis module, the flood control capacity review module, the seepage safety evaluation module, and the structural safety evaluation module.

2. The small reservoir dam safety and health evaluation system according to claim 1 is characterized in that: The on-site safety inspection module uses the following scoring table to evaluate the safety of the dam site Each item in the above table has three evaluation levels, and each level has a corresponding rating score, which are: A: 100; B: 50; C: 0; The total score for the on-site safety inspection module is: F1=avg(f 1,j ) (1) Among them, f 1,j is the jth on-site safety rating score, avg(·) is the average of ·, where when the on-site inspection of any part is graded C, the dam is rated as high risk. The on-site safety inspection module can be divided into the following categories according to the score F1: fourth class (0, 25], third class (25, 50], second class (50, 75], and first class (75, 100].

3. The small reservoir dam safety and health evaluation system according to claim 1 is characterized in that: The displacement statistical model of the dam during operation is shown in formula (2), from which the displacement effect value can be obtained: Where: is the constant regression coefficient (displacement model); is the water level related regression coefficient (displacement model); is the regression coefficient of time effect (displacement model); is the corresponding water level of the upstream and downstream reservoirs on the monitoring day of the i-th day; t is the calculation starting time, θ = t / 100; The statistical model of the piezometer of earth-rock dam is shown in formula (3), from which the effect value of seepage pressure can be obtained: Where: is the constant regression coefficient (pressure pipe model); is the mean water level correlation regression coefficient (pressure pipe model); is the regression coefficient of rainfall (pressure pipe model); is the time effect regression coefficient (pressure pipe model); is the average upstream water level in the previous i days; is the average rainfall in the previous i days; The seepage model of earth-rock dam adopts formula (4), and the effect value of seepage can be obtained: Where: is the constant regression coefficient (seepage model); is the water level correlation regression coefficient (seepage model); is the mean water level correlation regression coefficient (seepage model); is the rainfall regression coefficient (seepage model); is the time effect regression coefficient (seepage model); According to the observation data and environmental variables, a statistical mathematical model (Formula 2-4) is established to obtain different types of effect values. and its confidence interval with Δ ty : D ty =±βS ty (5) Where: ty = d, h, q; S ty is the standard deviation of the statistical model; β is a function of the significance level α, where α=1%, β=2.576; α=5%, β=1.96; if the measured value is within Δ ty If it is within the range, the dam is considered to be operating safely, otherwise, it may be abnormal; Therefore, the control index of the monitoring quantity It can be written as: Then the measured value is compared with the control index interval to obtain the safety monitoring data rating score f 2j They are: 100, 50, 0 respectively; then, the total score of the safety monitoring data analysis module is: F2=avg(f 2j ) (7) The safety monitoring data analysis module can be divided into the following categories according to the score F2: fourth class (0, 25], third class (25, 50], second class (50, 75], and first class (75, 100].

4. The small reservoir dam safety and health evaluation system according to claim 1 is characterized in that: The flood control capacity review module obtains the flood control capacity score by the following method; wherein the predicted water level h y It can be solved by iteratively using the water balance equation. The specific formula is as follows: Where: A s is the reservoir surface area; s is the reservoir water level; t is time; Q in is the inflow flow; Q spill is the outflow of the spillway; Q sluice is the gate outflow; The corresponding predicted water level h can be obtained through the water balance equation y , based on the actual engineering data, the dam top elevation h d and the initial water level h0, the corresponding flood control capacity score can be obtained: The flood control capacity review module can be divided into the following categories according to the score F3: fourth class (0, 25], third class (25, 50], second class (50, 75], and first class (75, 100].

5. The small reservoir dam safety and health evaluation system according to claim 1 is characterized in that: The critical hydraulic gradient adopts the piping type with the highest risk factor. The allowable hydraulic gradient J can be calculated using formula (10): 允许 , its expression: Where: K is the permeability coefficient of the soil; d3 is the particle size of the soil corresponding to the soil weight being less than 3% of the total weight; n is the porosity; the hydraulic drop threshold J is C The threshold coefficient (C) can be used to adjust the allowable hydraulic gradient to obtain the secondary control index, which is as follows: I c =CJ 允许 (11) Where: J C is the C-level hydraulic gradient threshold; C is the threshold coefficient, which is 0.8 and 1.2 respectively, and can be adjusted according to the importance of hydraulic structures; the seepage safety rating score (f 4,j ):100,50,0; For leakage, the allowable leakage q 允许 It can be obtained based on the upstream and downstream water levels and dam geometric conditions. The specific expression is as follows: Where H1 is the upstream water level; H2 is the downstream water level; L is the horizontal distance between the upstream and downstream water levels; the leakage threshold q C The threshold coefficient (C) can be used to adjust the allowable hydraulic gradient to obtain the secondary control index, which is as follows: q C =Cq 允许 (13) Where: q C is the C-level seepage threshold, C is the threshold coefficient, which is 0.8 and 1.2 respectively, and can be adjusted according to the importance of hydraulic structures; by comparing the j-th monitored seepage volume with the control index interval range, the seepage safety rating score (f 4,j ):100,50,0; By summarizing the hydraulic gradient and seepage rating scores, the score of the seepage safety evaluation module can be calculated by the following formula: F4=avg(f 4,j ) (14) The seepage safety evaluation module can be divided into the following categories according to the score F4: fourth class (0, 25], third class (25, 50], second class (50, 75], and first class (75, 100].

6. The small reservoir dam safety and health evaluation system according to claim 1 is characterized in that: The maximum dam height (H max ) as the secondary control index, and the safety of the deformed structure is discussed in a graded manner. Then the control index D C According to the following formula: D C =CH max (15) Where: H max is the maximum dam height, C is the threshold coefficient, which is 0.01 and 0.03 respectively. By comparing the jth monitored settlement displacement with the control index range, the corresponding structural safety rating score (f 5,j ):100,50,0; Two-level control index of stability structure safety (S C ) can be determined by the following formula: S C =CS 允许 (16) Where: Allowable safety factor S 允许 is 1.1, C is the threshold coefficient, which is 1.0 and 1.2 respectively. By comparing the calculated safety factor S with the control index range, the corresponding structural safety rating score (f 5,j ): 100, 50, 0; the safety factor is determined by the Swedish strip method. When the geotechnical structure is discretized into m soil strips for analysis, according to the limit equilibrium state principle, the sliding moment = anti-sliding moment, and the safety factor S is: Where: c m , W m are the cohesion, internal friction angle and weight of the mth soil block, respectively, l m ,θ m are the length and horizontal angle of the sliding surface where the mth soil block is located respectively; By summing up the deformation and stability structural safety rating scores, it can be calculated by the following formula: F5=avg(f 5,j ) (18) The submodule ratings can be divided into the following categories based on the score F5: fourth class (0, 25], third class (25, 50], second class (50, 75], and first class (75, 100].

7. The small reservoir dam safety and health evaluation system according to claim 1 is characterized in that: The total score of dam safety and health is expressed as: in, is the overall score of the dam; F U Score the Uth submodule, U = 1, 2, 3, 4, 5, corresponding to the on-site safety inspection module, safety monitoring data analysis module, flood control capacity review module, seepage safety evaluation module and structural safety evaluation module respectively; Q U is the weight coefficient of the Uth submodule. The overall rating of the dam can be divided into the following categories: low risk (0, 25], medium risk (25, 50], relatively high risk (50, 75], and high risk (75, 100]; the weight coefficient range is [0, 1].

8. A method for evaluating the safety and health of a small reservoir dam based on the small reservoir dam safety and health evaluation system according to any one of claims 1 to 7, comprising the following steps: (1) Basic data summary: The basic data of the dam is obtained through the basic information of the dam, test data and on-site inspection data, including: The basic information of the dam includes dam height, upstream and downstream slope ratio, dam top width, dam bottom width, cohesion of dam materials, internal friction angle of dam materials, permeability coefficient of dam materials, reservoir capacity curve, and discharge curve; monitoring data includes displacement monitoring data and its relative position, pressure measuring tube monitoring data and its relative position, seepage flow monitoring data and its relative position, upstream and downstream water levels, rainfall, temperature, and inflow; (2) The corresponding scores F are calculated in parallel for the on-site safety inspection module, safety detection data analysis module, flood control capacity review module, seepage safety module and structural safety evaluation module. I The scoring is divided into four intervals based on the percentage system: (75, 100], (50, 75], (25, 50], (0, 25], and the rating of each sub-item is determined accordingly: first class, second class, third class, fourth class; (3) The total score of dam safety and health is calculated based on the scores of each module and expressed as: in, is the overall score of the dam; F U Score the Uth submodule, U = 1, 2, 3, 4, 5, corresponding to the on-site safety inspection module, safety monitoring data analysis module, flood control capacity review module, seepage safety evaluation module and structural safety evaluation module respectively; Q U is the weight coefficient of the Uth submodule. The overall rating of the dam can be divided into the following categories: low risk (0, 25], medium risk (25, 50], relatively high risk (50, 75], and high risk (75, 100]; the weight coefficient range is [0, 1].

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