Method for predicting crack occurrence risk of earth and rockfill dam by using settlement monitoring data

Abstract

The invention relates to the technical field of water conservancy projects, in particular to a method for predicting the crack occurrence risk of an earth and rockfill dam through settlement monitoring data, the high, medium and low risk levels of a dam body are comprehensively judged by calculating and analyzing the vertical displacement rate, the settlement rule, the longitudinal inclination, the longitudinal tensile strain and the settlement rate, and the crack occurrence risk is predicted through the method. The method can prompt patrol key points, find potential safety hazards in advance, prevent dangerous cases such as landslide and collapse, provide technical support for reservoir safety identification, risk removal reinforcement and operation management, provide technical schemes for digital reservoir construction, and guarantee safe operation of reservoir engineering.

Description

Technical Field

[0001] The invention relates to the technical field of water conservancy engineering, and in particular to a method for predicting the risk of cracks in earth-rock dams by using settlement monitoring data. Background Art

[0002] As an important structure of water conservancy projects, reservoir dams have played a huge role in flood prevention and disaster reduction, hydropower generation, urban and rural water supply, agricultural irrigation, etc. The failure of reservoir dams will cause huge economic losses and social impacts. How to detect the safety hazards of dams in advance and ensure the safety of projects has always been the focus of research.

[0003] In the past, crack detection mainly relied on manual inspections. However, cracks often occur from the inside out and from small to large. They are not easy to detect through manual inspections. In addition, manual inspections have low frequency and high professional requirements, which can easily lead to missing the best time to discover hidden dangers.

[0004] In recent years, dam monitoring has become increasingly automated and intelligent. Dams have been installed with automated settlement monitoring facilities such as GNSS, static levels, water tube settlement meters, measuring robots, and machine vision. How to use monitoring data to automatically, intelligently, and in real time predict, forecast, and warn of dam safety has become a research hotspot.

[0005] Based on this, this case is brought forward. Summary of the invention

[0006] The purpose of the present invention is to provide a method for predicting the risk of cracks in an earth-rock dam using settlement monitoring data, so as to realize automatic, intelligent and real-time prediction, forecasting and early warning of dam safety using monitoring data.

[0007] To achieve the above object, the technical solution of the present invention is as follows:

[0008] A method for predicting the risk of cracks in an earth-rock dam using settlement monitoring data comprises the following steps:

[0009] Calculate the vertical displacement rate and classify the dam body safety into three levels: high risk, medium risk and low risk according to the vertical displacement rate;

[0010] Analyze the settlement rules. Use continuous monitoring data to establish an optimized statistical model of vertical displacement, time and water level. Analyze and predict the dam settlement based on the statistical model. At the same time, separate variable analysis is performed to classify the dam safety into two levels: medium risk and low risk.

[0011] Calculate the longitudinal inclination and classify the dam body safety into two levels: medium risk and low risk according to the longitudinal inclination;

[0012] Calculate the longitudinal tensile strain and classify the dam body safety into two levels: medium risk and low risk according to the magnitude of the longitudinal tensile strain;

[0013] Calculate the settlement rate and classify the dam safety into two levels: medium risk and low risk according to the settlement rate;

[0014] Comprehensive judgment:

[0015] If the vertical displacement rate is high risk, the comprehensive judgment of dam safety is high risk;

[0016] If at least two of the vertical displacement rate, settlement law, longitudinal inclination, longitudinal tensile strain, and settlement rate are medium risk, the comprehensive judgment of the dam safety level is high risk;

[0017] If only one of the vertical displacement rate, settlement law, longitudinal inclination, longitudinal tensile strain, and settlement rate is of medium risk, the comprehensive judgment of the dam body safety level is medium risk;

[0018] If the vertical displacement rate, settlement pattern, longitudinal inclination, longitudinal tensile strain and settlement rate are all low risk, the comprehensive judgment of the dam safety level is low risk.

[0019] Furthermore, the vertical displacement rate calculation includes the following process:

[0020] The vertical displacement rate is the ratio of the total vertical displacement to the thickness of the dam soil layer:

[0021]

[0022] Where, ρ is the vertical displacement rate; St is the total vertical displacement; d is the thickness of the dam soil layer;

[0023] When ρ≥3%, it means that the possibility of cracks in the dam body is very high, and the safety level of the dam body is high risk;

[0024] When 3%>ρ≥1%, it means that cracks may occur in the dam body, and the safety level of the dam body is medium risk;

[0025] When ρ<1%, it means that the possibility of cracks in the dam body is very small, and the safety level of the dam body is low risk.

[0026] Furthermore, the settlement law analysis includes the following processes:

[0027] Using continuous monitoring data, an optimized statistical model of vertical displacement, time and water level is established. The model is as follows:

[0028]

[0029] Where δ is the amount of sedimentation; a i d iis the statistical model coefficient; H i The i-th power of the reservoir water level on that day; is the previous average water level; c1 is the regression coefficient of the linear term of the time-effect component; c2 is the regression coefficient of the logarithmic term of the time-effect component; θ is the number of days from the beginning of a certain engineering measure divided by 100, that is, it increases by 1 every 100 days; b0 is a constant term;

[0030] The dam settlement is analyzed and predicted based on the statistical model, and the water level H i , Early water level Separate variable analysis was performed on the time-dependent linear term c1 and the time-dependent logarithmic term c2;

[0031] Determine the degree of influence of each influencing factor and the proportion of the influence of the time-dependent linear item. If the proportion of the time-dependent linear item is not less than 50%, there is no convergence trend in the settlement, cracks may occur in the dam body, and the safety level of the dam body is medium risk; if the proportion of the time-dependent linear item is less than 50%, the settlement area is stable, the possibility of cracks in the dam body is small, and the safety level of the dam body is low risk.

[0032] Furthermore, the longitudinal inclination calculation includes the following process:

[0033] The calculation formula of longitudinal inclination is as follows:

[0034]

[0035] In the formula, γ AB is the longitudinal inclination of two connected points; Δl is the distance between the two measuring points; S A , S B is the vertical displacement of the measuring point;

[0036] If γ AB Not less than 0.8%, the possibility of cracks in the dam body is high, and the dam body safety level is medium risk;

[0037] If γ AB If it is less than 0.8%, the possibility of cracks in the dam body is small and the safety level of the dam body is low risk.

[0038] Furthermore, the longitudinal tensile strain calculation includes the following process:

[0039] The calculation formula for longitudinal tensile strain is shown as follows:

[0040]

[0041] In the formula, ε x is the longitudinal horizontal tensile strain; c is the topographic coefficient of the valley, generally c = 0.3 ~ 0.5; Δl is the distance between the two measuring points; H maxis the maximum dam height; S1, S2, S3 are the total vertical displacements of three points arranged in sequence;

[0042] If the ultimate tensile strain value ε x Not less than 0.1%, the possibility of cracks in the dam body is high, and the dam body safety level is medium risk;

[0043] If ε x Less than 0.1%, the possibility of cracks in the dam body is small, and the safety level of the dam body is low risk.

[0044] Further, the sedimentation rate calculation includes the following process:

[0045] The settlement rate is calculated by using the fitted vertical displacement single factor model to obtain the derivative value and comparing it with the thickness of the lower soil layer. The calculation formula is as follows:

[0046]

[0047] Where v is the vertical displacement rate; S′(t) is the vertical displacement derivative; d is the thickness of the dam soil layer;

[0048] When the vertical displacement rate is not less than 0.0002, the possibility of cracks in the dam body is high, and the safety level of the dam body is medium risk;

[0049] When the vertical displacement rate is less than 0.0002, the possibility of cracks in the dam body is small and the safety level of the dam body is low risk.

[0050] The advantages of the present invention are: using this method to predict the risk of cracks can indicate inspection priorities, discover potential safety hazards early, prevent landslides, collapses and other dangerous situations, provide technical support for reservoir safety appraisal, risk removal and reinforcement, and operation management, provide technical solutions for digital reservoir construction, and ensure the safe operation of reservoir projects. DETAILED DESCRIPTION

[0051] The present invention is further described in detail below in conjunction with the embodiments. It should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside" and the like used herein to indicate directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0052] The present embodiment provides a method for predicting the risk of cracks in an earth-rock dam using settlement monitoring data, by calculating the vertical displacement rate, settlement law, longitudinal inclination, longitudinal tensile strain, and settlement rate, and by analyzing the above factors to determine the safety risk level of the dam body under each factor, so as to comprehensively judge the safety risk of the dam body. The specific process is described as follows.

[0053] Calculate the vertical displacement rate:

[0054] The vertical displacement rate (vertical displacement per meter) is calculated as the ratio of the total vertical displacement to the thickness of the dam soil layer.

[0055]

[0056] Where:

[0057] ρ——vertical displacement rate;

[0058] S t ——total vertical displacement;

[0059] d——the thickness of the soil layer of the dam body.

[0060] When the vertical displacement rate ρ ≥ 3%, there is a high possibility of cracks in the dam body, which is a high risk; when the vertical displacement rate ρ ≥ 3%, there is a high possibility of cracks in the dam body, which is a medium risk; when the vertical displacement rate ρ < 1%, there is a low possibility of cracks in the dam body, which is a low risk.

[0061] Sedimentation rules:

[0062] Using continuous monitoring data, an optimized statistical model of vertical displacement, time and water level is established. The model is as follows:

[0063]

[0064]

[0065] Where:

[0066] δ is the sedimentation amount;

[0067] a i d i is the statistical model coefficient, a i d i It is the best estimate obtained by fitting a statistical model using a historical data set;

[0068] H.H 2 , H 3 It is the 1st, 2nd and 3rd power of the reservoir water level on that day;

[0069] They are the average water level of the previous 1 to 3 days, the average water level of the previous 4 to 10 days, and the average water level of the previous 11 to 30 days;

[0070] c1 is the linear term regression coefficient of the time-effect component;

[0071] c2 is the regression coefficient of the logarithmic term of the time-effect component;

[0072] θ is the number of days from the beginning of a certain engineering measure divided by 100, that is, it increases by 1 every 100 days;

[0073] b0 is a constant term.

[0074] The statistical model can be used to analyze and predict the dam settlement and the water level (H, H 2 , H 3 ), early water level Separate variable analysis is performed on the linear term (c1) of the time-effect component and the logarithmic term (c2) of the time-effect component. The influence degree of each influencing factor is determined, and the influence proportion of the linear term of the time-effect component is determined. If the linear term of the time-effect component accounts for no less than 50%, there is no convergence trend in the settlement, and cracks may occur in the dam body, which is a medium risk; if the linear term of the time-effect component accounts for less than 50%, the settlement area is stable, and the possibility of cracks in the dam body is small, which is a low risk.

[0075] Longitudinal inclination calculation:

[0076] The calculation formula of longitudinal inclination is as follows:

[0077]

[0078] Where:

[0079] γ AB ——longitudinal inclination between two connected points;

[0080] Δl——the distance between two measuring points;

[0081] S A , S B ——Vertical displacement of the measuring point (total settlement).

[0082] If γ AB Not less than 0.8%, the possibility of cracks in the dam body is high, which is a medium risk; if γ AB Less than 0.8%, the possibility of cracks in the dam body is small and the risk is low.

[0083] Longitudinal tensile strain calculation:

[0084] The calculation formula for longitudinal tensile strain is shown as follows:

[0085]

[0086] Where:

[0087] ε x ——longitudinal horizontal tensile strain;

[0088] c——the topographic coefficient of the river valley, generally c=0.3~0.5;

[0089] Δl——the distance between two measuring points;

[0090] H max ——maximum dam height;

[0091] S1, S2, S3 – total vertical displacement of three points arranged in sequence.

[0092] If the ultimate tensile strain value ε x Not less than 0.1% of the dam body has a high probability of cracks, which is a medium risk. x Less than 0.1%, the possibility of cracks in the dam body is small and the risk is low.

[0093] Sedimentation rate:

[0094] The settlement rate is calculated by using the fitted vertical displacement single factor model to obtain the derivative value and comparing it with the thickness of the lower soil layer. The formula is as follows:

[0095]

[0096] Where:

[0097] v——vertical displacement rate;

[0098] S′(t)——vertical displacement derivative;

[0099] d——the thickness of the soil layer of the dam body.

[0100] When the vertical displacement rate is greater than 0.0002, there is a high possibility of cracks in the dam body, which is a medium risk. When v is less than 0.0002, there is a low possibility of cracks in the dam body, which is a low risk.

[0101] Comprehensive judgment:

[0102] If the vertical displacement rate is high risk, the comprehensive judgment of dam safety is high risk;

[0103] If at least two of the vertical displacement rate, settlement law, longitudinal inclination, longitudinal tensile strain, and settlement rate are medium risk, the comprehensive judgment of the dam safety level is high risk;

[0104] If only one of the vertical displacement rate, settlement law, longitudinal inclination, longitudinal tensile strain, and settlement rate is of medium risk, the comprehensive judgment of the dam body safety level is medium risk;

[0105] If the vertical displacement rate, settlement pattern, longitudinal inclination, longitudinal tensile strain and settlement rate are all low risk, the comprehensive judgment of the dam safety level is low risk.

[0106] The above embodiments are only used to explain the concept of the present invention, rather than to limit the protection of the rights of the present invention. Any non-substantial changes to the present invention using this concept shall fall within the protection scope of the present invention.

Claims

1. A method for predicting the risk of cracks in earth-rock dams using settlement monitoring data, characterized in that: The following steps are involved: Calculate the vertical displacement rate and classify the dam body safety into three levels: high risk, medium risk and low risk according to the vertical displacement rate; Analyze the settlement rules. Use continuous monitoring data to establish an optimized statistical model of vertical displacement, time and water level. Analyze and predict the dam settlement based on the statistical model. At the same time, separate variable analysis is performed to classify the dam safety into two levels: medium risk and low risk. Calculate the longitudinal inclination and classify the dam body safety into two levels: medium risk and low risk according to the longitudinal inclination; Calculate the longitudinal tensile strain and classify the dam body safety into two levels: medium risk and low risk according to the magnitude of the longitudinal tensile strain; Calculate the settlement rate and classify the dam safety into two levels: medium risk and low risk according to the settlement rate; Comprehensive judgment: If the vertical displacement rate is high risk, the comprehensive judgment of dam safety is high risk; If at least two of the vertical displacement rate, settlement law, longitudinal inclination, longitudinal tensile strain, and settlement rate are medium risk, the comprehensive judgment of the dam safety level is high risk; If only one of the vertical displacement rate, settlement law, longitudinal inclination, longitudinal tensile strain, and settlement rate is of medium risk, the comprehensive judgment of the dam body safety level is medium risk; If the vertical displacement rate, settlement pattern, longitudinal inclination, longitudinal tensile strain and settlement rate are all low risk, the comprehensive judgment of the dam safety level is low risk.

2. A method for predicting the risk of cracks in an earth-rock dam using settlement monitoring data as claimed in claim 1, characterized in that: The vertical displacement rate calculation includes the following process: The vertical displacement rate is the ratio of the total vertical displacement to the thickness of the dam soil layer: Where, ρ is the vertical displacement rate; St is the total vertical displacement; d is the thickness of the dam soil layer; When ρ≥3%, it means that the possibility of cracks in the dam body is very high, and the safety level of the dam body is high risk; When 3%>ρ≥1%, it means that cracks may occur in the dam body, and the safety level of the dam body is medium risk; When ρ<1%, it means that the possibility of cracks in the dam body is very small, and the safety level of the dam body is low risk.

3. The method for predicting the risk of cracks in earth-rock dams using settlement monitoring data according to claim 1, characterized in that: The settlement law analysis includes the following processes: Using continuous monitoring data, an optimized statistical model of vertical displacement, time and water level is established. The model is as follows: Where δ is the amount of sedimentation; a i d i is the statistical model coefficient; H i is the i-th power of the reservoir water level on that day; is the average water level in the previous period; c1 is the regression coefficient of the linear term of the time-effect component; c2 is the regression coefficient of the logarithmic term of the time-effect component; θ is the number of days from the beginning of a certain engineering measure divided by 100, that is, it increases by 1 every 100 days; b0 is a constant term; The dam settlement is analyzed and predicted based on the statistical model, and the water level H i , Early water level Separate variable analysis was performed on the time-dependent linear term c1 and the time-dependent logarithmic term c2; Determine the degree of influence of each influencing factor and the proportion of the influence of the linear term of the time-dependent component. If the proportion of the linear term of the time-dependent component is not less than 50%, there is no convergence trend in the settlement, cracks may occur in the dam body, and the safety level of the dam body is medium risk; if the proportion of the linear term of the time-dependent component is less than 50%, the settlement area is stable, the possibility of cracks in the dam body is small, and the safety level of the dam body is low risk.

4. The method for predicting the risk of cracks in earth-rock dams using settlement monitoring data according to claim 1, characterized in that: The longitudinal inclination calculation includes the following process: The calculation formula of longitudinal inclination is as follows: In the formula, γ AB is the longitudinal inclination of two connected points; Δl is the distance between the two measuring points; S A , S B is the vertical displacement of the measuring point; If γ AB Not less than 0.8%, the possibility of cracks in the dam body is high, and the dam body safety level is medium risk; If γ AB If it is less than 0.8%, the possibility of cracks in the dam body is small and the safety level of the dam body is low risk.

5. The method for predicting the risk of cracks in an earth-rock dam using settlement monitoring data as claimed in claim 1, characterized in that: The longitudinal tensile strain calculation includes the following processes: The calculation formula for longitudinal tensile strain is shown as follows: In the formula, ε x is the longitudinal horizontal tensile strain; c is the topographic coefficient of the valley, generally c = 0.3 ~ 0.5; Δl is the distance between the two measuring points; H max is the maximum dam height; S1, S2, S3 are the total vertical displacements of three points arranged in sequence; If the ultimate tensile strain value ε x Not less than 0.1%, the possibility of cracks in the dam body is high, and the dam body safety level is medium risk; If ε x Less than 0.1%, the possibility of cracks in the dam body is small, and the dam body safety level is low risk.

6. The method for predicting the risk of cracks in earth-rock dams using settlement monitoring data according to claim 1, characterized in that: The sedimentation rate calculation includes the following process: The settlement rate is calculated by using the fitted vertical displacement single factor model to obtain the derivative value and comparing it with the thickness of the lower soil layer. The calculation formula is as follows: Where v is the vertical displacement rate; S ′ (t) is the vertical displacement derivative; d is the thickness of the dam soil layer; When the vertical displacement rate is not less than 0.0002, the possibility of cracks in the dam body is high, and the safety level of the dam body is medium risk; When the vertical displacement rate is less than 0.0002, the possibility of cracks in the dam body is small and the safety level of the dam body is low risk.

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