A method and system for monitoring the deformation of a dam body in a water conservancy project

Abstract

The present invention relates to the technical field of building deformation monitoring, and particularly relates to a method and system for monitoring the deformation of a dam in a water conservancy project. The voltage time-series signals output by the fiber optic stress sensors at multiple monitoring points in the monitoring area are acquired, and the differences between any two voltage time-series signals in the time domain and the frequency domain are fused to obtain the degree of fiber optic stretching in the monitoring area. Then, in combination with the overall temperature anomaly degree in the monitoring area, the output quantity in the process of converting the grating wavelength into an electrical signal in the fiber optic stress sensor is corrected. The overall temperature anomaly degree is obtained from the temperature anomaly values of each monitoring point, which can eliminate the change in the electrical signal caused by temperature changes in the fiber optic stress sensor, realize the drift compensation of the detection signal of the fiber optic stress sensor, eliminate the influence of errors, and improve the accuracy of dam deformation monitoring in water conservancy projects.

Description

Technical Field

[0001] The present invention relates to the technical field of building deformation monitoring, and particularly to a method and system for monitoring the deformation of a dam in a water conservancy project. Background Art

[0002] Dams in water conservancy projects are usually used to intercept water flows to form reservoirs, regulate water flow, generate electricity, irrigate, etc. The shape and structure of the dam are designed according to specific topographical features, hydrological conditions, and engineering requirements. Generally, they can be divided into the following main types: gravity dams, arch dams, earth-rock dams, and concrete face rockfill dams, etc. Among them, the basic principle of most dams is a retaining wall structure that uses its own weight for stability, usually in a straight or arc shape, and generally trapezoidal when viewed from the side. It is applicable to areas with hard geology and high foundation bearing capacity; or it is built with earth and rock materials, usually with a trapezoidal cross-section, including earth dams and rock dams, which are suitable for a wide range of topographical conditions.

[0003] The deformation monitoring of the dam is of vital importance. In the prior art, the methods for dam deformation monitoring mainly include: GPS monitoring: By installing GPS devices on the dam, the displacement and deformation of the dam are monitored in real time; leveling: Using a level to regularly monitor the marking points on the dam to obtain vertical displacement data; total station monitoring: Using a total station to measure the displacement of the dam surface or specific positions to obtain three-dimensional position information; in-situ stress and strain monitoring: Embedding strain gauges and stress gauges inside the dam to directly measure the stress and deformation state of the dam.

[0004] Optical fiber sensing technology is very useful in the health monitoring of dams and other large structures due to its corrosion resistance, high sensitivity, non-polarity, and ability to perform long-distance distributed measurement. In strain monitoring, optical fiber stress sensors are usually used to detect the deformation of the dam.

[0005] In the detection of dam deformation using optical fiber stress sensors, based on the conversion relationship between the optical signal and the electrical signal of the optical fiber stress sensor, due to the complexity of the environment, such as factors like different weather conditions and light changes, it will cause temperature fluctuations in the dam detection area. These temperature changes will also affect the change of the electrical signal of the optical fiber stress sensor, thereby affecting the accuracy of the signal of the true stress change, and thus reducing the accuracy of dam deformation monitoring. Summary of the Invention

[0006] In order to solve the technical problem of the low accuracy of the existing method for monitoring the deformation of a dam in a water conservancy project using an optical fiber stress sensor, the purpose of the present invention is to provide a method and system for monitoring the deformation of a dam in a water conservancy project. The specific technical solutions adopted are as follows:

[0007] In the first aspect of the present invention, a method for monitoring the deformation of a dam in a water conservancy project is provided, including:

[0008] Obtain the voltage time series signals output by the fiber optic stress sensors at multiple monitoring points within the monitoring area;

[0009] Fuse the differences between any two of the voltage time series signals in the time domain and the frequency domain to obtain the degree of fiber optic stretching in the monitoring area;

[0010] According to the degree of fiber optic stretching in the monitoring area and the overall temperature anomaly degree in the monitoring area, correct the output quantity during the process of converting the grating wavelength into an electrical signal in the fiber optic stress sensor; the overall temperature anomaly degree is obtained from the temperature anomaly values at each monitoring point.

[0011] In an exemplary embodiment, the fusing the differences between any two of the voltage time series signals in the time domain and the frequency domain to obtain the degree of fiber optic stretching in the monitoring area includes:

[0012] Obtain the amplitude linear displacement property of the monitoring area according to the difference in the voltage values corresponding to the extreme points in any two of the voltage time series signals;

[0013] Obtain the degree of electrical data characteristic anomaly in the monitoring area according to the difference in the number of extreme points in any two of the voltage time series signals and the phase difference in the frequency domain signal;

[0014] Obtain the degree of fiber optic stretching in the monitoring area according to the amplitude linear displacement property and the degree of electrical data characteristic anomaly; both the amplitude linear displacement property and the degree of electrical data characteristic anomaly are proportional to the degree of fiber optic stretching.

[0015] In an exemplary embodiment, the obtaining the amplitude linear displacement property of the monitoring area according to the difference in the voltage values corresponding to the extreme points in any two of the voltage time series signals includes:

[0016] Respectively obtain the maximum value sets of the first voltage time series signal and the second voltage time series signal, and obtain the union of the moments of the maximum value sets of the first voltage time series signal and the second voltage time series signal; the first voltage time series signal and the second voltage time series signal are any two voltage time series signals;

[0017] Obtain the voltage value difference between each moment in the union of moments in the first voltage time series signal and the second voltage time series signal;

[0018] Fuse the voltage value differences corresponding to all moments in the union of moments to obtain the amplitude linear displacement property of the monitoring area.

[0019] In an exemplary embodiment, the fusing the voltage value differences corresponding to all moments in the union of moments to obtain the amplitude linear displacement property of the monitoring area includes:

[0020] Calculate the average value of the voltage value differences corresponding to all the moments in the moment union to obtain the overall voltage difference between the first voltage time series signal and the second voltage time series signal;

[0021] Calculate the average value of the overall voltage differences between all any two voltage time series signals and normalize it to obtain the amplitude linear displacement property of the monitoring area.

[0022] In an exemplary embodiment, obtaining the abnormal degree of the electrical data characteristics of the monitoring area according to the difference in the number of extreme points in any two of the voltage time series signals and the phase difference in the frequency domain signal includes:

[0023] Obtain the number of maximum values of the first voltage time series signal and the second voltage time series signal, and obtain the difference in the number of maximum values of the first voltage time series signal and the second voltage time series signal; the first voltage time series signal and the second voltage time series signal are any two voltage time series signals;

[0024] Convert the first voltage time series signal and the second voltage time series signal into frequency domain signals respectively, and obtain the phase difference between the frequency domain signals of the first voltage time series signal and the second voltage time series signal;

[0025] Fuse the difference in the number of maximum values and the phase difference to obtain the abnormal degree of the electrical data characteristics of the monitoring area.

[0026] In an exemplary embodiment, fusing the difference in the number of maximum values and the phase difference to obtain the abnormal degree of the electrical data characteristics of the monitoring area includes:

[0027] Calculate the product of the difference in the number of maximum values and the phase difference between the first voltage time series signal and the second voltage time series signal to obtain the sub-abnormal degree of the data corresponding to the first voltage time series signal and the second voltage time series signal;

[0028] Calculate the average value of the sub-abnormal degrees of the data corresponding to all any two voltage time series signals and normalize it to obtain the abnormal degree of the electrical data characteristics of the monitoring area.

[0029] In an exemplary embodiment, the temperature anomaly value of the monitoring point is the isolation forest score value of the monitoring point; the overall temperature anomaly degree is the average value of the isolation forest score values of all monitoring points.

[0030] In an exemplary embodiment, correcting the output quantity in the process of converting the grating wavelength into an electrical signal in the fiber optic stress sensor according to the fiber stretching degree of the monitoring area and the overall temperature anomaly degree of the monitoring area includes:

[0031] Obtain a correction coefficient according to the fiber stretching degree and the overall temperature anomaly degree of the monitoring area;

[0032] Based on the correction coefficient and the original output quantity in the process of converting the grating wavelength in the fiber optic stress sensor into an electrical signal, the corrected output quantity in the process of converting the grating wavelength in the fiber optic stress sensor into an electrical signal is obtained.

[0033] In an exemplary embodiment, the method for monitoring the deformation of the dam body of a water conservancy project further includes:

[0034] Compare the overall temperature anomaly degree with a preset temperature anomaly degree threshold;

[0035] If the overall temperature anomaly degree is greater than the preset temperature anomaly degree threshold, output a temperature interference warning instruction.

[0036] In a second aspect of the present invention, there is provided a system for monitoring the deformation of a dam body of a water conservancy project, including: a memory and a processor; the memory is connected to the processor; the memory is used to store program instructions; the processor is used to implement the above-mentioned method for monitoring the deformation of the dam body of a water conservancy project when the program instructions are executed.

[0037] The present invention has the following beneficial effects: Multiple monitoring points are set in the monitoring area, each monitoring point is provided with a fiber optic stress sensor, each monitoring point also acquires temperature, and at the same time, the characteristics of the voltage time series signals output by the fiber optic stress sensors of any two monitoring points are analyzed in the time domain and the frequency domain, and according to the differences in the characteristics in the time domain and the frequency domain, the degree of fiber stretching in the monitoring area is obtained. Finally, according to the degree of fiber stretching in the monitoring area, combined with the overall temperature anomaly degree of the monitoring area with respect to temperature, the output quantity in the process of converting the grating wavelength in the fiber optic stress sensor into an electrical signal is corrected, which can eliminate the change in the electrical signal brought by the temperature change to the fiber optic stress sensor, realize the drift compensation of the detection signal of the fiber optic stress sensor, eliminate the error influence, and improve the accuracy of the deformation monitoring of the dam body of the water conservancy project. Description of the Drawings

[0038] Figure 1 is a flowchart of a method for monitoring the deformation of a dam body of a water conservancy project provided by an embodiment of the present invention;

[0039] Figure 2 is a flowchart for obtaining the degree of fiber stretching provided by an embodiment of the present invention;

[0040] Figure 3 is a flowchart for obtaining the amplitude linear displacement provided by an embodiment of the present invention;

[0041] Figure 4 is a specific calculation process diagram of the amplitude linear displacement provided by an embodiment of the present invention;

[0042] Figure 5 It is a flowchart for obtaining the abnormal degree of electrical data characteristics provided by an embodiment of the present invention;

[0043] Figure 6 It is a specific calculation process diagram for the abnormal degree of electrical data characteristics provided by an embodiment of the present invention;

[0044] Figure 7 It is a correction process diagram provided by an embodiment of the present invention;

[0045] Figure 8 It is a flowchart of the steps further included in a method for monitoring the deformation of a dam body of a water conservancy project provided by an embodiment of the present invention. Specific Embodiments

[0046] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following describes in detail the specific embodiments, structures, features and effects of the present invention in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The data information collected in this application has been obtained with full consent and authorization, and the collection, use and processing of relevant information need to comply with the relevant laws, regulations and standards of relevant countries and regions.

[0048] The application scenario of a method for monitoring the deformation of a dam body of a water conservancy project provided in this embodiment is: determining the monitoring area for monitoring the deformation of the dam body of a water conservancy project, and the monitoring area is usually the key area of the dam body of a water conservancy project. In the dam body of a water conservancy project, one monitoring area can be set, or multiple monitoring areas can be set. In an exemplary embodiment, the structure of the dam body is often complex and the bearing capacity is uneven, so the monitoring area can be selected according to its different structural functions and importance. The divided monitoring areas include: the core area of the dam body: the base of the dam body, the middle and upper parts of the dam body; the corners and joints of the dam body: the corner parts of the dam body are places where the mechanical stress is relatively large; the spillway, drainage system and anti-seepage area of the dam body: these areas are related to the change of water pressure in the dam body.

[0049] A plurality of monitoring points are set in the monitoring area, and the number and layout of the monitoring points are set according to actual needs, such as grid layout. Each monitoring point is equipped with a fiber optic stress sensor and a temperature sensor. The fiber optic stress sensor is a fiber optic grating sensor used to detect stress deformation, and is used to monitor the changes of physical quantities such as stress and strain of the corresponding monitoring point in real time; the temperature sensor is used to detect the temperature of the corresponding monitoring point.

[0050] In an exemplary embodiment, the sensitivity of the fiber optic stress sensor is typically between 1 - 2 pm / με (picometers per microstrain). Assuming a strain change of 10 με, the wavelength change is approximately 10 - 20 pm; the wavelength range is typically 1500 - 1600 nm, and the common reflection wavelength is 1550 nm; the accuracy is generally within 1 pm, capable of accurately reflecting small - scale deformations; the operating temperature is from - 40°C to 85°C, suitable for different climate and environmental conditions.

[0051] The temperature change of the temperature sensor will affect the readings of the fiber optic stress sensor. Therefore, a temperature sensor needs to be configured for compensation. The sensitivity of the temperature sensor is from 0.1°C to 0.5°C, which can be reflected by the temperature sensor; the operating temperature range of the temperature sensor is from - 40°C to 85°C; the accuracy of the temperature sensor is ±0.1°C.

[0052] Each fiber optic stress sensor transmits signals through optical fibers, and the temperature sensor transmits signals through data transmission lines or through a wireless communication module.

[0053] As Figure 1 shown, a method for monitoring the deformation of a dam body in a water conservancy project provided by this embodiment includes the following steps:

[0054] Step 1: Obtain the voltage time - series signals output by the fiber optic stress sensors at multiple monitoring points within the monitoring area.

[0055] Step 2: Fuse the differences between any two voltage time - series signals in the time domain and the frequency domain to obtain the degree of fiber optic stretching in the monitoring area.

[0056] Step 3: According to the degree of fiber optic stretching in the monitoring area and the overall temperature anomaly degree in the monitoring area, correct the output quantity during the process of converting the grating wavelength into an electrical signal in the fiber optic stress sensor; the overall temperature anomaly degree is obtained from the temperature anomaly values of each monitoring point.

[0057] The following specifically describes each step of a method for monitoring the deformation of a dam body in a water conservancy project provided by this embodiment in combination with the accompanying drawings.

[0058] Step 1: Obtain the voltage time - series signals output by the fiber optic stress sensors at multiple monitoring points within the monitoring area.

[0059] The fiber optic stress sensor is used to convert the detected optical signal into an electrical signal. Then, the voltage time - series signal output by the fiber optic stress sensor is the electrical signal output by the fiber optic stress sensor.

[0060] The sampling period (i.e., sampling frequency) of the fiber optic stress sensor is set according to actual needs. Moreover, the sampling periods of the fiber optic stress sensors at all monitoring points are the same, and the fiber optic stress sensors at all monitoring points sample synchronously. That is, at a certain moment, the voltage signals output by the fiber optic stress sensors at each monitoring point can be obtained.

[0061] In an exemplary embodiment, a monitoring time period is set. A method for monitoring the deformation of a dam body in a water conservancy project provided in this embodiment is used to correct the output of the fiber optic stress sensor according to the data in this monitoring time period. The duration of this monitoring time period, that is, the number of moments it contains, is set according to actual needs.

[0062] According to the voltage signals at each moment, a voltage time series signal output by the fiber optic stress sensor at the monitoring point is obtained. The voltage time series signal is obtained by arranging the voltage signals at each moment in time sequence. Thus, the voltage time series signals output by the fiber optic stress sensors at each monitoring point are obtained. The voltage time series signal is a signal whose voltage amplitude varies with time. It appears as a non-periodic signal with a finite time sequence. By capturing parameters such as the fiber optic wavelength through this non-periodic signal with a finite time sequence, the stress value at the monitoring point can be monitored. Different monitoring points have different detection results of fiber optic stress sensors.

[0063] The temperature sensor at the monitoring point obtains the temperature value of the monitoring point. It should be understood that the temperature time series signal of the monitoring point can also be obtained at the same sampling frequency as the above-mentioned fiber optic stress sensor. In this embodiment, the average value of the temperature values in the temperature time series signal detected by the temperature sensor at the monitoring point is calculated, and this average value is used as the temperature value of the monitoring point. Thus, the temperature values of each monitoring point are obtained.

[0064] Furthermore, the reason for collecting the temperature values of each monitoring point is explained: at different monitoring points, due to the influence of light, shadow, or weather conditions, the temperature at the monitoring point will fluctuate, and the fluctuating temperature will affect the stress electrical signal value at the monitoring point, thereby generating corresponding errors.

[0065] Collecting the temperature values of each monitoring point is for subsequent use as a comparison calculation compensation and participation in the calculation of the grating wavelength drift compensation of the fiber optic stress sensor.

[0066] Step 2: Integrate the differences between any two voltage time series signals in the time domain and the frequency domain to obtain the degree of fiber stretching in the monitoring area.

[0067] Generally, when there is no deformation in the dam body, the voltage time-series signal obtained by the fiber optic stress sensor will not change significantly, that is, it has relatively similar and regular characteristics at different times. When the dam body is deformed, stress changes occur in some areas of the dam body. When the stress increases, the optical fiber of the fiber optic stress sensor is stretched, the Bragg grating spacing increases, resulting in the center wavelength of the reflected light shifting towards the long-wavelength direction (red shift). The wavelength shift can be converted into a change in the corresponding voltage signal by the photodetector of the fiber optic stress sensor. Therefore, the amplitude of the voltage signal will change relative to the baseline signal. If it is a linear spectral demodulator, the wavelength change will cause a linear change in the output voltage amplitude. Then, when the voltage time-series signal at the monitoring point changes, that is, its voltage amplitude has a certain linear drift and the phase value also changes, it can be considered that the stress value change is caused by suspected deformation. Therefore, analyze the differences in the voltage time-series signals of any two monitoring points in the time domain and frequency domain, and fuse these differences of all any two monitoring points to obtain the degree of fiber stretching in the monitoring area.

[0068] In an exemplary embodiment, as Figure 2 shown, the following gives a specific acquisition process for the degree of fiber stretching in the monitoring area:

[0069] Step 2-1: Obtain the amplitude linear displacement of the monitoring area according to the difference in the voltage values corresponding to the extreme points in any two voltage time-series signals.

[0070] By analyzing the difference in the voltage values corresponding to the extreme points in the voltage time-series signals of any two monitoring points, obtain the voltage amplitude linear displacement of the voltage time-series signals of these two monitoring points, and then comprehensively consider the voltage amplitude linear displacement of all any two monitoring points to obtain the amplitude linear displacement of the monitoring area.

[0071] In an exemplary embodiment, as Figure 3 shown, the following gives a specific acquisition process for the amplitude linear displacement:

[0072] Step 2-1-1: Respectively obtain the maximum value sets of the first voltage time-series signal and the second voltage time-series signal, and obtain the union of the times of the maximum value sets of the first voltage time-series signal and the second voltage time-series signal.

[0073] For the convenience of description, set the first monitoring point and the second monitoring point as any two monitoring points, the first voltage time-series signal as the voltage time-series signal of the first monitoring point, and the second voltage time-series signal as the voltage time-series signal of the second monitoring point. Then, the first voltage time-series signal and the second voltage time-series signal are any two voltage time-series signals.

[0074] Obtain the maximum values in the first voltage timing signal, and sort the maximum values according to the moments of the maximum values in the first voltage timing signal to obtain the set of maximum values of the first voltage timing signal, which is defined as the first maximum value set. Then, obtain the moments corresponding to the maximum values in the first maximum value set to obtain the first moment set.

[0075] Similarly, obtain the maximum values in the first voltage timing signal, and sort the maximum values according to the moments of the maximum values in the second voltage timing signal to obtain the set of maximum values of the second voltage timing signal, which is defined as the second maximum value set. Then, obtain the moments corresponding to the maximum values in the second maximum value set to obtain the second moment set.

[0076] Then, obtain the union of the first moment set and the second moment set to obtain the moment union. For example: If the first moment set corresponding to the first maximum value set is: t12, t17, t23, t30, t39, t45, and the second moment set corresponding to the second maximum value set is: t10, t16, t23, t32, t39, t46, then the moment union of the first moment set and the second moment set is: t10, t12, t16, t17, t23, t30, t32, t39, t45, t46.

[0077] The maximum value can reflect the characteristic situation of the voltage timing signal, and by using the union method, all the maximum values in the two voltage timing signals can be considered simultaneously, improving the accuracy of data processing.

[0078] Step 2-1-2: Obtain the voltage value differences of each moment in the moment union in the first voltage timing signal and the second voltage timing signal.

[0079] Obtain the voltage values of each moment in the moment union in the first voltage timing signal, and obtain the voltage values of each moment in the moment union in the second voltage timing signal.

[0080] Then, calculate the voltage value differences of the voltage values of each moment in the moment union in the first voltage timing signal and the second voltage timing signal to obtain the voltage value differences corresponding to each moment. For example: Set any moment in the moment union as the i-th moment, and the calculation formula for the voltage value difference corresponding to the i-th moment is as follows:

[0081] ;

[0082] Among them, is the voltage value of the i-th moment in the moment union in the first voltage timing signal, that is, the voltage value of the i-th moment in the moment union in the first voltage timing signal; is the voltage value at the i-th moment in the moment union in the second voltage timing signal, that is, the voltage value at the i-th moment in the moment union of the second voltage timing signal; is the voltage value difference between the voltage values at the i-th moment in the first voltage timing signal and the second voltage timing signal in the moment union.

[0083] Step 2-1-3: Integrate the voltage value differences corresponding to all moments in the moment union to obtain the amplitude linear displacement property of the monitoring area.

[0084] By integrating the voltage value differences corresponding to all moments in the moment union, the overall voltage difference between the first voltage timing signal and the second voltage timing signal is obtained. Then, by synthesizing the overall voltage differences of any two voltage timing signals, the amplitude linear displacement property of the monitoring area is obtained.

[0085] In an exemplary embodiment, as Figure 4 shown, a specific calculation process of the amplitude linear displacement property is given as follows:

[0086] Step 2-1-3-1: Calculate the average value of the voltage value differences corresponding to all moments in the moment union to obtain the overall voltage difference between the first voltage timing signal and the second voltage timing signal.

[0087] Calculate the average value of the voltage value differences corresponding to all moments in the moment union to obtain the overall voltage difference between the first voltage timing signal and the second voltage timing signal, that is, the voltage amplitude difference characteristic between the first voltage timing signal and the second voltage timing signal. The calculation formula is as follows:

[0088] ;

[0089] where is the overall voltage difference between the first voltage timing signal and the second voltage timing signal, and I is the number of moments in the moment union.

[0090] Step 2-1-3-2: Calculate the average value of the overall voltage differences of any two voltage timing signals and normalize it to obtain the amplitude linear displacement property of the monitoring area.

[0091] Through Step 2-1-3-1, the overall voltage difference corresponding to each pair of voltage timing signals (a pair of voltage timing signals consists of two voltage timing signals) in the monitoring area can be obtained. Then, the overall voltage differences corresponding to all pairs of voltage timing signals in the monitoring area are averaged, and the obtained average value is normalized. The obtained normalized result is the amplitude linear displacement property of the monitoring area.

[0092] It should be understood that the normalization in this embodiment can be specifically set according to the actual situation. For example, linear normalization can be adopted, such as the maximum-minimum normalization method, or the following common methods can also be used: , represents the object to be processed, and exp represents the exponential function with the natural constant e as the base.

[0093] By analyzing the amplitude difference characteristics of the voltage signals between different monitoring points in the monitoring area, the amplitude linear displacement of the monitoring area is determined. When the overall voltage difference between different monitoring points is smaller, that is, the amplitude difference characteristics are less obvious, the amplitude linear displacement of the monitoring area is lower, indicating that in this monitoring area, the possibility of the stress value changing due to the dam body deformation and then causing the voltage signal to change is lower. On the contrary, the larger the value of the amplitude linear displacement of the monitoring area, the higher the linear quantity of the voltage data in the voltage amplitude dimension, and the higher the possibility of the dam body deformation.

[0094] Step 2-2: Obtain the abnormal degree of the electrical data characteristics of the monitoring area according to the difference in the number of extreme points in any two voltage time series signals and the phase difference in the frequency domain signal.

[0095] The single difference in the number of extreme points cannot fully reflect the linear quantity of the time series finite data in the monitoring area. The phase characteristics in the frequency domain signal also need to be combined because phase modulation is used as a measurement means in fiber optic stress sensors. The optical wave phase drift caused by stress change is converted into the phase change in the electrical signal through interferometric measurement. And the phase change is used as a technical means to compensate or improve the measurement accuracy.

[0096] Obtain the abnormal degree of the electrical data characteristics of the monitoring area according to the difference in the number of extreme points in any two voltage time series signals and the phase difference in the frequency domain signal.

[0097] In an exemplary embodiment, as Figure 5 shown, the following gives a specific acquisition process of the abnormal degree of the electrical data characteristics:

[0098] Step 2-2-1: Obtain the number of maximum values of the first voltage time series signal and the second voltage time series signal, and obtain the difference in the number of maximum values of the first voltage time series signal and the second voltage time series signal.

[0099] Obtain the number of maximum values in the first maximum value set to get the first number of maximum values; obtain the number of maximum values in the second maximum value set to get the second number of maximum values.

[0100] Obtain the maximum number difference between the first maximum number and the second maximum number. In an exemplary embodiment, calculate the absolute value of the difference between the first maximum number and the second maximum number as the maximum number difference between the first maximum number and the second maximum number.

[0101] Step 2-2-2: Convert the first voltage timing signal and the second voltage timing signal into frequency-domain signals respectively, and obtain the phase difference between the frequency-domain signals of the first voltage timing signal and the second voltage timing signal.

[0102] Since the voltage timing signal is a time-domain signal, then convert the first voltage timing signal into a first frequency-domain signal, and obtain the phase of the first frequency-domain signal, which is defined as the first phase; similarly, convert the second voltage timing signal into a second frequency-domain signal, and obtain the phase of the second frequency-domain signal, which is defined as the second phase.

[0103] Obtain the phase difference between the first phase and the second phase. In an exemplary embodiment, calculate the absolute value of the difference between the first phase and the second phase as the phase difference between the first phase and the second phase.

[0104] The phase difference can reflect the degree of drift in the fiber optic sensing process, and further reflect whether the dam deforms at different monitoring points, thereby causing a stress difference. The greater the phase difference, that is, the higher the voltage data difference between the corresponding two monitoring points, this phase difference reflects the difference in optical signals, and further a conclusion that stress changes may occur in the monitoring area can be obtained.

[0105] Step 2-2-3: Fuse the maximum number difference and the phase difference to obtain the abnormal degree of the electrical data characteristics in the monitoring area.

[0106] By performing a fusion analysis on the maximum number difference and the phase difference of the voltage timing signals of any two monitoring points, the abnormal degree of the electrical data characteristics in the monitoring area can be obtained. In an exemplary embodiment, as Figure 6 shown, the following gives a specific calculation process of the abnormal degree of the electrical data characteristics:

[0107] Step 2-2-3-1: Calculate the product of the maximum number difference and the phase difference between the first voltage timing signal and the second voltage timing signal to obtain the data sub-abnormal degree corresponding to the first voltage timing signal and the second voltage timing signal.

[0108] The calculation formula for the data sub-abnormal degree corresponding to the first voltage timing signal and the second voltage timing signal is as follows:

[0109] ;

[0110] where is the data sub-abnormality degree corresponding to the first voltage timing signal and the second voltage timing signal, is the difference in the number of maximum values corresponding to the first voltage timing signal and the second voltage timing signal, is the phase difference corresponding to the first voltage timing signal and the second voltage timing signal.

[0111] Step 2-2-3-2: Calculate the average value of the data sub-abnormality degrees corresponding to any two voltage timing signals and normalize it to obtain the abnormality degree of the electrical data characteristics in the monitoring area.

[0112] Through Step 2-2-3-1, the data sub-abnormality degree corresponding to each pair of voltage timing signals (a pair of voltage timing signals consists of two voltage timing signals) in the monitoring area can be obtained. Then, the average value of the data sub-abnormality degrees corresponding to all pairs of voltage timing signals in the monitoring area is calculated. Finally, the obtained average value is normalized, and the normalized result is the abnormality degree of the electrical data characteristics in the monitoring area.

[0113] Step 2-3: Obtain the fiber stretching degree in the monitoring area according to the amplitude linear displacement property and the abnormality degree of the electrical data characteristics.

[0114] According to the amplitude linear displacement property and the abnormality degree of the electrical data characteristics, the fiber stretching degree in the monitoring area is obtained. The fiber stretching degree is proportional to the amplitude linear displacement property, and the fiber stretching degree is proportional to the abnormality degree of the electrical data characteristics. In an exemplary embodiment, the product of the amplitude linear displacement property and the abnormality degree of the electrical data characteristics in the monitoring area is calculated as the fiber stretching degree in the monitoring area. The greater the fiber stretching degree in the monitoring area, the higher the linear quantity of the optical wave electrical data in the monitoring area, that is, the higher the possibility of stress abnormality caused by dam deformation.

[0115] In an exemplary embodiment, a fiber stretching degree threshold (such as 0.8) can also be preset. When the fiber stretching degree in the monitoring area is greater than the fiber stretching degree threshold, it is determined that there is a high probability of suspected deformation in the dam.

[0116] Step 3: Correct the output quantity in the process of converting the grating wavelength into an electrical signal in the fiber optic stress sensor according to the fiber stretching degree in the monitoring area and the overall temperature abnormality degree in the monitoring area; the overall temperature abnormality degree is obtained from the temperature abnormality values of each monitoring point.

[0117] The degree of fiber optic stretching in the monitoring area is theoretically in conflict with the change in the temperature value of the monitoring area, because both dam deformation (such as deformation caused by factors such as reservoir water level changes or earthquakes) and temperature changes will cause the wavelength of the fiber grating to drift, and this drift is mainly manifested as a change in the reflection wavelength of the grating. And the change in wavelength can indeed reflect the change in the corresponding physical quantity (such as stress or temperature). So in practical applications, the effects of stress and temperature will be intertwined, so it is necessary to distinguish between the two, especially when detecting electrical signals.

[0118] Therefore, it is necessary to obtain the overall temperature anomaly degree of the monitoring area, that is, the temperature jump value of the monitoring area, in order to analyze the interference degree of the temperature value of the monitoring area on the degree of fiber optic stretching.

[0119] First, obtain the temperature anomaly values of each monitoring point. The temperature anomaly values are used to characterize the temperature anomaly situation of the monitoring points. In an exemplary embodiment, the temperature anomaly value of a monitoring point is the isolation forest score value of the monitoring point. It should be understood that using the isolation forest algorithm, taking the temperature values of all monitoring points as samples, calculate the isolation forest score values of the temperature values of each monitoring point. The higher the isolation forest score value, the higher the degree of isolation and the more abnormal the temperature value. It should be understood that when the temperature value of a single monitoring point does not have the isolation characteristic, its isolation forest score value is 0. In other implementation manners, other anomaly detection algorithms can also be used to obtain the temperature anomaly values of each monitoring point. If the numerical range of the initially obtained temperature anomaly values of each monitoring point does not meet the 0-1 numerical range, normalization is required to bring the temperature anomaly values into the 0-1 numerical range for subsequent processing.

[0120] The overall temperature anomaly degree is obtained from the temperature anomaly values of each monitoring point. In an exemplary embodiment, calculate the average value of the isolation forest score values of all monitoring points, and this average value is the overall temperature anomaly degree of the monitoring area.

[0121] Then, according to the degree of fiber optic stretching in the monitoring area and the overall temperature anomaly degree of the monitoring area, correct the output quantity in the process of converting the grating wavelength into an electrical signal in the fiber optic stress sensor. In an exemplary embodiment, as Figure 7 shown, the following gives a specific correction process:

[0122] Step 3-1: Obtain a correction coefficient according to the degree of fiber optic stretching in the monitoring area and the overall temperature anomaly degree.

[0123] Obtain a correction coefficient according to the degree of fiber optic stretching in the monitoring area and the overall temperature anomaly degree. This correction coefficient refers to the weight value corresponding to each data in the process of transferring the grating wavelength drift to an electrical signal, that is, the grating wavelength drift compensation weight coefficient.

[0124] In an exemplary embodiment, calculate the product of the degree of optical fiber stretching and the degree of overall temperature anomaly in the monitoring area as the correction coefficient.

[0125] Step 3-2: Obtain the corrected output quantity in the process of converting the grating wavelength in the fiber optic stress sensor into an electrical signal according to the correction coefficient and the original output quantity in the process of converting the grating wavelength in the fiber optic stress sensor into an electrical signal.

[0126] In an exemplary embodiment, the correction calculation method is given as follows:

[0127] ;

[0128] Wherein, represents the corrected output quantity in the process of converting the grating wavelength in the fiber optic stress sensor into an electrical signal, represents the original output quantity in the process of converting the grating wavelength in the fiber optic stress sensor into an electrical signal, and r is the correction coefficient.

[0129] Based on the original output quantity, add the correction coefficient, and by reducing the electrical data value, reduce the data fluctuation degree under different monitoring points, so as to prevent abnormal stress judgment caused by the optical wave drift caused by the change of the temperature value.

[0130] In an exemplary embodiment, as Figure 8 shown, the dam deformation monitoring method provided in this embodiment further includes:

[0131] Step 4: Compare the overall temperature anomaly degree with the preset temperature anomaly degree threshold;

[0132] Step 5: If the overall temperature anomaly degree is greater than the preset temperature anomaly degree threshold, output a temperature interference warning instruction.

[0133] The higher the overall temperature anomaly degree, the stronger the temperature interference received by the optical fiber stretching in the fiber optic stress sensor. Therefore, a temperature anomaly degree threshold is preset, and this preset temperature anomaly degree threshold is set according to actual needs, such as 0.6.

[0134] If the overall temperature anomaly degree is greater than the preset temperature anomaly degree threshold, it is determined that there is strong temperature interference in the optical fiber stretching in the fiber optic stress sensor. Then, output a temperature interference warning instruction for the staff to obtain in time, so that relevant solutions can be taken in time.

[0135] In an exemplary embodiment, in subsequent applications, according to the corrected output quantity in the process of converting the grating wavelength in the fiber optic stress sensor into an electrical signal, obtain the dam stress values of each monitoring area. Determine the deformation result of the dam according to the dam stress value. This part is the prior art and is briefly described as follows. The process is:

[0136] Analysis of stress-deformation relationship: Based on the mechanical properties (Young's modulus) of the dam material and the geometric shape of the dam, establish the relationship between stress and deformation. Usually, the finite element analysis (FEA) method can be used, combined with the actually monitored stress data, to simulate the stress distribution in different monitoring areas and deduce the corresponding deformation.

[0137] Deformation calculation: Conduct deformation calculation through the relationship formula between stress and deformation (using the stress-strain formula in elasticity). Analyze the stress data of each monitoring point and calculate the deformation value (displacement, deformation amount, etc.) of this point.

[0138] Overall deformation evaluation of the dam body: Integrate the deformation results of each monitoring area and analyze the deformation trend and degree of the entire dam body. Usually, methods such as weighted average and integration are used to synthesize the deformation of the monitoring area into the overall deformation.

[0139] The advantages of a dam deformation monitoring method for a water conservancy project provided in this embodiment are as follows: 1) Monitor the monitoring area of the dam through fiber optic sensing technology, analyze the data change results, and obtain the deformation results of the dam, eliminating the problem of temperature difference confusion; 2) In fiber optic sensing technology, by converting light waves into electrical signals for analysis, temperature changes will also bring certain electrical signal changes. By analyzing the temperature anomalies and combining the temperature anomalies with the degree of fiber optic stretching, the drift compensation value in the corresponding light wave conversion electrical signal process is obtained to eliminate the error influence; 3) According to the stress change results without error in the monitoring area, the deformation amount and deformation possibility of the dam under the water conservancy project can be analyzed.

[0140] This embodiment also provides a dam deformation monitoring system for a water conservancy project, including: a memory and a processor; the memory is connected to the processor, and the memory is used to store program instructions; the processor is used to implement the steps in the above-mentioned dam deformation monitoring method embodiment when the program instructions are executed.

[0141] In an exemplary embodiment, the present invention provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, it implements the steps in the above-mentioned dam deformation monitoring method embodiment.

[0142] It should be noted that: The above sequence of the embodiments of the present invention is only for description and does not represent the superiority or inferiority of the embodiments. The processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be beneficial.

[0143] Each embodiment in this specification is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other, and the key point of each embodiment is to illustrate the differences from other embodiments.

Claims

1. A method for monitoring the deformation of a dam body in a water conservancy project, characterized in that, Including: Obtaining voltage time-series signals output by optical fiber stress sensors at multiple monitoring points within a monitoring area; Fusing the differences between any two of the voltage time-series signals in the time domain and the frequency domain to obtain the degree of optical fiber stretching in the monitoring area; wherein, the method for obtaining the degree of optical fiber stretching is: obtaining the amplitude linear displacement property of the monitoring area according to the difference in the voltage values corresponding to the extreme points in any two of the voltage time-series signals; obtaining the degree of abnormality of the electrical data characteristics of the monitoring area according to the difference in the number of extreme points in any two of the voltage time-series signals and the phase difference in the frequency-domain signal; obtaining the degree of optical fiber stretching in the monitoring area according to the amplitude linear displacement property and the degree of abnormality of the electrical data characteristics; both the amplitude linear displacement property and the degree of abnormality of the electrical data characteristics are proportional to the degree of optical fiber stretching; According to the degree of optical fiber stretching in the monitoring area and the degree of overall temperature abnormality in the monitoring area, correcting the output quantity during the process of converting the grating wavelength into an electrical signal in the optical fiber stress sensor; the degree of overall temperature abnormality is obtained from the temperature abnormality values of each monitoring point.

2. The deformation monitoring method of a water conservancy project dam body according to claim 1, characterized in that, The obtaining the amplitude linear displacement property of the monitoring area according to the difference in the voltage values corresponding to the extreme points in any two of the voltage time-series signals includes: Respectively obtaining the maximum value sets of the first voltage time-series signal and the second voltage time-series signal, and obtaining the union of the moments of the maximum value sets of the first voltage time-series signal and the second voltage time-series signal; the first voltage time-series signal and the second voltage time-series signal are any two voltage time-series signals; Obtaining the voltage value difference at each moment in the moment union in the first voltage time-series signal and the second voltage time-series signal; Fusing the voltage value differences corresponding to all moments in the moment union to obtain the amplitude linear displacement property of the monitoring area.

3. A deformation monitoring method for a dam body of a water conservancy project according to claim 2, characterized in that, The fusing the voltage value differences corresponding to all moments in the moment union to obtain the amplitude linear displacement property of the monitoring area includes: Calculating the average value of the voltage value differences corresponding to all moments in the moment union to obtain the overall voltage difference between the first voltage time-series signal and the second voltage time-series signal; Calculating the average value of the overall voltage differences of all any two voltage time-series signals and normalizing it to obtain the amplitude linear displacement property of the monitoring area.

4. The deformation monitoring method for a dam body of a water conservancy project according to claim 1, characterized in that, The obtaining the degree of abnormality of the electrical data characteristics of the monitoring area according to the difference in the number of extreme points in any two of the voltage time-series signals and the phase difference in the frequency-domain signal includes: Obtaining the number of maximum values of the first voltage time-series signal and the second voltage time-series signal, and obtaining the difference in the number of maximum values of the first voltage time-series signal and the second voltage time-series signal; the first voltage time-series signal and the second voltage time-series signal are any two voltage time-series signals; Respectively converting the first voltage time-series signal and the second voltage time-series signal into frequency-domain signals, and obtaining the phase difference of the frequency-domain signals of the first voltage time-series signal and the second voltage time-series signal; Fusing the difference in the number of maximum values and the phase difference to obtain the degree of abnormality of the electrical data characteristics of the monitoring area.

5. The method for monitoring the deformation of a dam body in a water conservancy project according to claim 4, characterized in that, Fusing the difference in the number of maxima and the phase difference to obtain the degree of abnormality of the electrical data characteristics in the monitoring area includes: Calculating the product of the difference in the number of maxima and the phase difference between the first voltage time-series signal and the second voltage time-series signal to obtain the data sub-abnormality degree corresponding to the first voltage time-series signal and the second voltage time-series signal; Calculating and normalizing the average value of the data sub-abnormality degrees corresponding to any two voltage time-series signals to obtain the degree of abnormality of the electrical data characteristics in the monitoring area.

6. The deformation monitoring method of a water conservancy project dam body according to claim 1, characterized in that The temperature anomaly value of the monitoring point is the isolation forest score value of the monitoring point; the overall temperature anomaly degree is the average value of the isolation forest score values of all monitoring points.

7. The deformation monitoring method of a dam body in a water conservancy project according to claim 1, characterized in that Modifying the output quantity in the process of converting the grating wavelength into an electrical signal in the fiber optic stress sensor according to the degree of fiber stretching in the monitoring area and the overall temperature anomaly degree in the monitoring area includes: Obtaining a correction coefficient according to the degree of fiber stretching in the monitoring area and the overall temperature anomaly degree; Obtaining the corrected output quantity in the process of converting the grating wavelength into an electrical signal in the fiber optic stress sensor according to the correction coefficient and the original output quantity in the process of converting the grating wavelength into an electrical signal in the fiber optic stress sensor.

8. A deformation monitoring method for a dam body of a water conservancy project according to claim 1, characterized in that, The dam deformation monitoring method for water conservancy projects further includes: Comparing the overall temperature anomaly degree with a preset temperature anomaly degree threshold; If the overall temperature anomaly degree is greater than the preset temperature anomaly degree threshold, output a temperature interference warning instruction.

9. A dam deformation monitoring system for water conservancy projects, characterized in that, Including: A memory and a processor; The memory is connected to the processor; The memory is used to store program instructions; The processor is used to implement the dam deformation monitoring method for water conservancy projects according to any one of claims 1-8 when the program instructions are executed.

Images