Reinforced concrete pipeline deterioration detection method and system, device, and storage medium

Abstract

The present invention relates to the technical field of pipeline test. Disclosed are a reinforced concrete pipeline deterioration detection method and system, a device, and a storage medium. The method comprises: constructing an initial finite element pipeline model according to pipeline parameters of a pipeline to be tested; by means of the digital image technology, constructing a stress-strain field of said pipeline; determining the precision of the initial finite element pipeline model according to a strain cloud map of the stress-strain field, and adjusting the initial finite element pipeline model according to a determination result, so as to obtain a finite element pipeline model; and generating a typical load-displacement curve of said pipeline according to the finite element pipeline model, and calculating a deterioration degree index of said pipeline according to the typical load-displacement curve. By means of fusion of the digital image technology and the finite element technology, the present invention can comprehensively reflect the degree of damage of a structural body and accurately represent the deterioration condition of a long-term operation structure in real time, thereby improving the operation and maintenance safety for pipeline network systems.

Description

Reinforced concrete pipe deterioration detection method, system, equipment and storage medium Technical Field

[0001] The present invention relates to the technical field of pipeline detection, and in particular to a reinforced concrete pipeline deterioration detection method, system, equipment and storage medium. Background Art

[0002] From the 1980s to the early 21st century, China constructed a vast amount of municipal pipe network infrastructure. However, due to historical reasons, these pipe networks were inconsistent in standards and quality, and were under-managed and poorly maintained. This has led to frequent problems such as urban waterlogging, black and odorous water bodies, and road collapses in recent years. With technological advancements, a variety of drainage pipe repair methods have been developed, including local repair, comprehensive renewal, and replacement of deteriorated pipes. A crucial step in the pipe repair process is a detailed analysis, assessment, and quantification of the degree of deterioration of existing pipes. Quantifying the degree of pipe deterioration not only impacts the operational and maintenance safety of the pipe network system but also directly influences the decision-making process for repairs.

[0003] Currently, inspection methods for deteriorating reinforced concrete pipes are primarily categorized into three types: non-destructive, semi-destructive, and destructive. Non-destructive testing techniques primarily include ultrasonic testing, radar measurement, and infrared thermal imaging; semi-destructive testing primarily employs the rebound method for structural strength testing; and destructive testing primarily utilizes core drilling. However, these techniques only provide partial inspection of aging structures and cannot fully reflect the extent of structural damage. Therefore, they cannot accurately and timely characterize the deterioration of long-term operational structures.

[0004] Summary of the Invention

[0005] In order to solve the above-mentioned technical problems, the present invention provides a reinforced concrete pipe deterioration detection method, system, equipment and storage medium, which can solve the problem that existing detection technologies cannot effectively quantify and evaluate deteriorated concrete pipes in situ, and achieve the effect of accurately characterizing the degree of deterioration of reinforced concrete pipes.

[0006] In a first aspect, the present invention provides a method for detecting deterioration of reinforced concrete pipes, the method comprising:

[0007] Constructing an initial finite element pipeline model according to the pipeline parameters of the pipeline to be inspected;

[0008] Using digital image technology to construct the stress and strain field of the pipeline to be inspected;

[0009] Determining the accuracy of the initial finite element pipeline model based on the strain cloud diagram of the stress-strain field, and adjusting the initial finite element pipeline model based on the determination result to obtain a finite element pipeline model;

[0010] A typical load-displacement curve of the pipeline to be inspected is generated according to the finite element pipeline model, and a degradation degree index of the pipeline to be inspected is calculated according to the typical load-displacement curve.

[0011] Furthermore, the step of constructing the stress and strain field of the pipeline to be inspected using digital image technology includes:

[0012] Acquire time-series images of the inner wall of the pipeline to be inspected by a binocular camera;

[0013] Performing mapping transformation on the pixel coordinates of the time-series image, and traversing the pixels of the time-series image after the mapping transformation to obtain an image displacement relationship;

[0014] According to the image displacement relationship, the strain value of each pixel point is calculated, and the stress-strain field of the pipeline to be inspected is generated according to the strain value.

[0015] Furthermore, the step of determining the accuracy of the initial finite element pipeline model based on the strain cloud diagram of the stress-strain field, and adjusting the initial finite element pipeline model according to the determination result to obtain the finite element pipeline model includes:

[0016] Acquire a first strain nephogram of the stress-strain field and a second strain nephogram generated by the initial finite element pipeline model corresponding to the first strain nephogram;

[0017] Converting the first strain cloud map and the second strain cloud map into a first distribution matrix and a second distribution matrix respectively through image binarization;

[0018] subtracting the second distribution matrix from the first distribution matrix to obtain a difference matrix, and ratioing each element of the difference matrix with each element of the first distribution matrix to obtain a difference ratio matrix;

[0019] Calculating an average value of the sum of the elements in the difference ratio matrix, and determining whether the average value is less than an accuracy threshold;

[0020] If so, the initial finite element pipeline model is used as the finite element pipeline model; otherwise, the initial finite element pipeline model is adjusted until the finite element pipeline model is obtained.

[0021] Furthermore, the step of obtaining a first strain nephogram of the stress-strain field and a second strain nephogram generated by the initial finite element pipeline model corresponding to the first strain nephogram includes:

[0022] Acquire an initial longitudinal deformation of the pipeline to be inspected, a first strain nephogram of the stress-strain field, and a first longitudinal deformation corresponding to the first strain nephogram;

[0023] Selecting a corresponding strain frame from a strain cloud map generated by the initial finite element pipeline model according to the initial longitudinal deformation and the first longitudinal deformation, the strain frame including a first strain frame and a second strain frame;

[0024] A strain increment is obtained according to an RGB difference between the first strain frame and the second strain frame, and a second strain cloud map is generated according to the strain increment.

[0025] Furthermore, before determining the accuracy of the initial finite element pipeline model based on the strain cloud diagram of the stress-strain field, the method further includes:

[0026] Acquire a first strain nephogram of the stress-strain field and a second strain nephogram generated by the initial finite element pipeline model corresponding to the first strain nephogram;

[0027] Comparing the accuracy of the first strain nephogram and the second strain nephogram, and determining whether the comparison result is greater than an accuracy threshold;

[0028] If so, it is determined that the initial finite element pipeline model meets the accuracy condition; otherwise, the initial finite element pipeline model is adjusted until the initial finite element pipeline model meets the accuracy condition.

[0029] Furthermore, before determining the accuracy of the initial finite element pipeline model based on the strain cloud diagram of the stress-strain field, the method further includes:

[0030] Determining whether the initial longitudinal deformation of the pipeline to be inspected is greater than an aging threshold;

[0031] If yes, then the mechanical properties simulation test of the initial finite element pipeline model is performed to obtain the simulated mechanical parameters and simulated strain cloud diagram of the pipeline to be tested;

[0032] Dividing the pipeline to be inspected into regions, and dividing each region into sub-regions according to the simulated strain cloud map;

[0033] generating a reduction coefficient for each sub-region according to the area of ​​each sub-region and the corresponding simulation mechanical parameter;

[0034] According to the reduction coefficient, the initial finite element pipeline model is subjected to a partitioned constitutive reduction.

[0035] Furthermore, the step of calculating the degradation index of the pipeline to be inspected based on the typical load-displacement curve includes:

[0036] According to the load-displacement relationship, the typical load-displacement curve is converted into a segmented model;

[0037] Selecting a corresponding segmented expression from the segmented model according to a comparison result between the current longitudinal deformation of the pipeline to be tested and the limit displacement in the typical load-displacement curve;

[0038] The residual strength of the pipeline to be inspected is calculated according to the segmented expression, and the residual strength is used as an indicator of the degree of deterioration of the pipeline to be inspected.

[0039] In a second aspect, the present invention provides a reinforced concrete pipe deterioration detection system, the system comprising:

[0040] A model building module is used to build an initial finite element pipeline model according to pipeline parameters of the pipeline to be inspected;

[0041] A strain field construction module, configured to construct the stress and strain field of the pipeline to be inspected using digital image technology;

[0042] a model adjustment module, configured to determine the accuracy of the initial finite element pipeline model based on the strain cloud diagram of the stress-strain field, and to adjust the initial finite element pipeline model based on the determination result to obtain a finite element pipeline model;

[0043] The index calculation module is used to generate a typical load-displacement curve of the pipeline to be inspected based on the finite element pipeline model, and calculate the degradation degree index of the pipeline to be inspected based on the typical load-displacement curve.

[0044] In a third aspect, an embodiment of the present invention further provides a computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the computer program.

[0045] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of the above method when executed by a processor.

[0046] This invention provides a reinforced concrete pipeline deterioration detection method, system, computer device, and storage medium. This method integrates digital imaging technology with finite element analysis to create a reliable, refined three-dimensional pipeline model using a limited set of inspection images. This allows for characterization and evaluation of damage initiation, development, and evolution throughout the pipeline's lifecycle. This provides effective data support for establishing inspection and repair decision-making plans throughout the pipeline's lifecycle, and offers a solution for future digital twin modeling of municipal pipelines. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] FIG1 is a schematic flow chart of a method for detecting deterioration of reinforced concrete pipes according to an embodiment of the present invention;

[0048] FIG2 is a schematic diagram of pipeline structure detection and data collection in an embodiment of the present invention;

[0049] FIG3 is a schematic diagram of a three-dimensional model structure of a pipeline in an embodiment of the present invention;

[0050] FIG4 is a schematic diagram of a detection method using a digital image processing system according to an embodiment of the present invention;

[0051] FIG5 is a schematic diagram of a process of partitioned constitutive reduction in an embodiment of the present invention;

[0052] FIG6 is a schematic diagram of a typical load-displacement curve and a segmented model of a pipeline in an embodiment of the present invention;

[0053] 7 is another schematic flow chart of a reinforced concrete pipe deterioration detection method according to an embodiment of the present invention;

[0054] FIG8 is a schematic structural diagram of a reinforced concrete pipe degradation detection system according to an embodiment of the present invention;

[0055] FIG9 is a diagram showing the internal structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0056] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0057] Referring to FIG1 , a method for detecting deterioration of reinforced concrete pipes according to a first embodiment of the present invention includes steps S10 to S40 :

[0058] Step S10: constructing an initial finite element pipeline model according to the pipeline parameters of the pipeline to be inspected.

[0059] In an embodiment of the present invention, a refined three-dimensional finite element pipeline model is established for the structural damage of the aging pipeline. Please refer to Figures 2 and 3. The steps of the construction include:

[0060] Through the investigation of the surrounding environment and the inspection of the pipeline structure, the relevant parameters of the pipeline to be inspected are obtained. Specifically, the surrounding environment of the reinforced concrete drainage pipeline structure to be inspected is investigated. The contents of the investigation include drainage pipeline specifications such as the diameter and wall thickness of the pipeline in its initial state, the type of concrete used, the type of steel bar used and the reinforcement parameters, etc., as well as the buried depth of the pipeline and the overlying soil information, so as to obtain the initial structural parameters of the pipeline to be inspected, such as the buried age, buried depth, pipe diameter at the time of initial burial, pipe wall thickness, steel cage reinforcement parameters, concrete grade, steel grade, etc.

[0061] Then, a local strength test is performed on the pipeline to be tested. The strength test of the aged concrete structure can be carried out in the uncarbonized area using the Schmidt hammer rebound 2 as the main test method and the core drilling method 1 as an auxiliary method. In order to ensure the safety of the existing structure and the accuracy of the test results, the data should be calibrated by comparing with the core drilling test results before using the rebound hammer test.

[0062] During the inspection, record the time of intervention testing, and place the hammer head of the rebound hammer close to the surface of the pipe to be tested, ensuring that it is perpendicular to the surface. Hold the handle of the rebound hammer with your hand to ensure that it is stable and does not shake. Use moderate force to quickly release the hammer head toward the pipe surface through the handle, allowing it to rebound and hit the pipe surface. Observe the pointer or digital display on the rebound hammer and record the rebound value. Average the recorded rebound values ​​to obtain the average rebound value for each test location. Use relevant standards or empirical formulas to convert the average rebound value into a strength index for the pipe, and conduct a correlation analysis between the degree of aging and strength to evaluate the overall strength changes of the pipe. Through local strength testing, concrete mechanical parameters such as the uniaxial compressive strength of concrete and the elastic modulus of concrete in the aged structural area can be obtained.

[0063] Furthermore, it is also necessary to obtain the distribution of steel bars in the pipeline. Therefore, in this embodiment, electromagnetic wave technology and electromagnetic induction technology 3 are used to detect the position and wall thickness of the steel bars, and full-pipe detection of the pipeline to be detected 5 is performed to obtain the overall information of the steel bars in the pipeline, that is, the structural parameters of the steel bars. In order to clarify the impact of the degree of steel bar corrosion in the aging structure on the strength of the steel bars, a limited group of steel bar samples can be collected on site, that is, the local pipe section with the smallest impact area on the drainage pipe is selected, and the steel bars at the dangerous points are sampled to conduct tensile strength, tensile modulus, bending strength and bending modulus tests on the steel bars to obtain the tensile stress, tensile modulus and elastic modulus of the steel bars. At the same time, ultrasonic technology 4 is used to detect the global wall thickness value of the pipeline monitoring section.

[0064] In addition, it is necessary to sample the soil 12 around the pipe to obtain the backfill form of the soil 12 around the pipe, randomly select soils of different burial depths and different positions for uniaxial compression tests, and test their strength, cohesion, internal friction angle, water content, compression modulus and other parameters, so as to obtain the basic parameters of the soil.

[0065] After obtaining the pipeline parameters through the above steps, the pipeline model can be constructed based on the parameters. First, based on the external environmental conditions of the drainage pipeline when the intervention inspection begins, the detailed parameters such as the current buried depth of the pipeline, the vertical deformation of the pipeline, the thickness and material parameters of the overburden layer on the top of the pipe, the pavement foundation geometry and material parameters, traffic load and groundwater distribution are clarified and statistically quantified in a table. Using numerical analysis software, according to the Mohr-Coulomb theory of soil, a three-dimensional soil model is established based on the collected basic soil parameters such as soil cohesion, internal friction angle, density, water content, soil modulus and soil layer size information. The geometric modeling tools provided by the numerical analysis software, such as drawing, solid modeling or importing existing geometric data, are used to create the geometric shape of the model and define the geometric characteristics of the pipeline components in the soil structure.

[0066] Then select the Mohr-Coulomb constitutive model and define the relevant material property parameters for the soil. Preferably, select the concrete plastic damage constitutive model and the ideal elastic-plastic constitutive model respectively, and define the parameters for the concrete pipe and steel cage respectively based on the obtained structural parameters and mechanical parameters related to the concrete and steel bars. Use finite element software to perform meshing and discretize the geometric model into a finite element mesh. And define the nodes, associate the nodes with the mesh, and specify the degrees of freedom of the nodes, such as displacement or rotation. Define boundary conditions, such as fixed supports, loading position and size, initial conditions, etc. These conditions will be applied to the corresponding nodes in the simulation, and the various components such as soil, pipes, steel cages, etc. will be assembled into a complete model. Use connection, fit or contact definitions to simulate the interaction and contact between components to ensure that the constraints and contact relationships between components are correctly defined.

[0067] Based on statistical information, accurately evaluate and convert surface loads10 and traffic loads11 according to AASHTOLRFD standards, clearly define the pipeline impact area, and apply equivalent surface loads and traffic loads. Set parameters such as the loading time step and loading rate, and define the total simulation time or number of steps. Configure analysis options, such as convergence criteria and relaxation factors, to ensure simulation stability and accuracy. Configure Abaqus solver options, such as the iterative solver type and parallel computing settings, to obtain an initial finite element pipeline model.

[0068] Step S20: constructing the stress and strain field of the pipeline to be inspected by using digital imaging technology.

[0069] While constructing the initial finite element pipeline model, this embodiment also uses digital images to construct the stress and strain field of the inner wall of the pipeline. Please refer to Figure 4. The sewage in the pipeline to be inspected is removed, and the binocular camera system 8 is installed in the pipeline through the inspection well 6 and the camera telescopic rod 7. Marking points 9, such as waterproof circular marking patches with a diameter of 5 mm, are pasted on the inspection section of the inner wall of the pipeline.

[0070] After calibrating the binocular camera system 8, determine its absolute position (x0, y0, z0). Capture an image frame at intervals T, and record the capture time. It's important to note that the sewage inside the pipe should be removed during each capture, and the waterproof markings 9 on the pipe wall should be clearly visible. The captured images are then processed to construct the stress-strain field. The specific steps are as follows:

[0071] Step S201, obtaining time-series images of the inner wall of the pipeline to be inspected by a binocular camera;

[0072] Step S202, mapping and transforming the pixel coordinates of the time-series image, and performing pixel traversal on the time-series image after mapping and transformation to obtain an image displacement relationship;

[0073] Step S203 : calculating the strain value of each pixel point according to the image displacement relationship, and generating the stress-strain field of the pipeline to be inspected according to the strain value.

[0074] In this embodiment, the images obtained by the left and right cameras are sorted in chronological order and marked on the left and right sides to obtain a time-series image of the inner wall. Based on the initial image, any point A(X1, X2, X3) in the real environment is mapped to a point I(XI1, XI2, XI3) in a pixel of the image in the camera coordinate system. The mapping relationship can be expressed as: XI = r ij X+t ij Among them, r ij (i, j = 1, 2, 3) and t i (i=1, 2, 3) are the rotation vector and translation vector from point A to point I. After normalizing the points in the camera image, we can get: i =XI i / XI3, using camera parameters such as focal length (f1, f2), optical point center coordinates (C1, C2) and camera tilt coefficient s, the image coordinates I (XI1, XI2, XI3) obtained by the camera are compared with the normalized coordinates I' (x p ,y p ) can be transformed into:

[0075] Then, by traversing each pixel in the image, the coordinate value of each pixel in the camera normalized coordinate system is obtained:

[0076] Where x ck and y ck are the x and y coordinates of the initial reference point, x ckz and y ckz is the coordinate of the center of the initial reference point, x i and y i is the coordinate of the current point, and the deformation is parameterized by the displacement u and v and their partial derivatives. For a given reference set, the u and v parameters are constants. i ,y i Coordinates, the displacement value w with sub-pixel accuracy can be obtained L ii and w R ii , that is, the displacement value of the left lens test of the binocular camera and the displacement value of the right lens test of the binocular camera.

[0077] According to the formula ε ii =(w L ii -w R ii ) / Z 0 ii , get the strain value ε in the ii direction ii , where Z 0 ii is the original distance between the two points in the ii direction, and according to the formula ε VonMises =Sqrt{1 / 2[(ε 11 -ε 22 ) 2 +(ε 22 -ε 33 ) 2 +(ε 33 -ε 11 ) 2 ]}, the engineering Mises strain is obtained, thereby generating the stress-strain field of the pipeline to be tested.

[0078] Step S30 , judging the accuracy of the initial finite element pipeline model according to the strain cloud diagram of the stress-strain field, and adjusting the initial finite element pipeline model according to the judgment result to obtain a finite element pipeline model.

[0079] In order to improve the accuracy of the constructed model, the present invention integrates digital imaging technology with finite element technology. The stress and strain field generated by digital imaging technology is used to verify the accuracy of the initial finite element pipeline model. The specific steps are as follows:

[0080] Step S301 : obtaining a first strain nephogram of the stress-strain field and a second strain nephogram generated by the initial finite element pipeline model corresponding to the first strain nephogram.

[0081] In this embodiment, a first strain nephogram is first obtained based on the constructed stress-strain field. Based on the first strain nephogram, a corresponding second strain nephogram is selected from the strain nephogram obtained by simulating the initial finite element pipeline model. The specific steps are as follows:

[0082] Step S3011, obtaining the initial longitudinal deformation of the pipeline to be inspected, the first strain nephogram of the stress-strain field, and the first longitudinal deformation corresponding to the first strain nephogram;

[0083] Step S3012: selecting a corresponding strain frame from the strain cloud map generated by the initial finite element pipeline model according to the initial longitudinal deformation and the first longitudinal deformation, wherein the strain frame includes a first strain frame and a second strain frame;

[0084] Step S3013: Obtain a strain increment according to the RGB difference between the first strain frame and the second strain frame, and generate a second strain contour map according to the strain increment.

[0085] Specifically, based on the pipeline image during interventional inspection, the Mises strain diagram of the inspection surface at any time during the inspection phase is obtained as the first strain cloud diagram, and the vertical deformation D1 of the pipeline during interventional inspection and the deformation D2 of the pipeline at the time point corresponding to the extracted Mises strain state are obtained as the initial longitudinal deformation and the first longitudinal deformation, respectively.

[0086] The initial finite element model is used to simulate and run the whole process to obtain the inner wall strain value ε of the pipeline as the loading increment changes. ii The strain cloud map is extracted according to the pipe deformation parameters D1 and D2. The corresponding frames in the incremental step are extracted. After aligning the scale range of each frame, the image is grayed out, the RGB value is extracted, and the RGB values ​​of the two images are subtracted to obtain ε ii The strain increment relationship is obtained, and according to the strain formula of the engineering Mises strain, the numerical analysis Mises strain result is obtained. The strain result is the strain nephogram, which is the second strain nephogram corresponding to the first strain nephogram.

[0087] Step S302 , converting the first strain cloud map and the second strain cloud map into a first distribution matrix and a second distribution matrix respectively through image binarization;

[0088] Step S303: subtracting the second distribution matrix from the first distribution matrix to obtain a difference matrix, and performing ratio calculations on each element of the difference matrix with each element of the first distribution matrix to obtain a difference ratio matrix;

[0089] Step S304, calculating the average value of the sum of the elements in the difference ratio matrix, and determining whether the average value is less than the accuracy threshold;

[0090] Step S305: If yes, the initial finite element pipeline model is used as the finite element pipeline model; otherwise, the initial finite element pipeline model is adjusted until the finite element pipeline model is obtained.

[0091] After obtaining the first strain cloud map and the second strain cloud map, the two cloud maps are converted into numerical distribution matrices A and B respectively through image binarization. Then, matrix B is subtracted from matrix A to obtain the difference matrix C0. The elements in the difference matrix C0 are compared with the elements in matrix A one by one to generate the difference ratio matrix C. Finally, the average value q of the sum of each element in matrix C is calculated and compared with the preset accuracy threshold q0. The condition for meeting the accuracy requirement is H0:q <q0。

[0092] If the initial finite element model meets the accuracy requirements, it is used as the final finite element pipeline model. If it does not meet the accuracy requirements, the model's material partitioning and mesh parameters need to be further refined, and refined numerical analysis and calculations are performed until the adjusted model meets the accuracy requirements. This embodiment uses digital imaging technology to construct a stress-strain field for the pipeline to be inspected, and verifies the accuracy of the model constructed using finite element technology based on the actual strain field of the pipeline. This achieves the integration of digital imaging technology and finite element technology, effectively improving the accuracy of the finite element pipeline model, and thus improving the accuracy of the pipeline degradation determination results.

[0093] Furthermore, in order to better improve the data accuracy of the finite element pipeline, the present invention provides a preferred embodiment, through which the accuracy of the model is verified. The specific verification steps are:

[0094] Before determining the accuracy of the initial finite element pipeline model based on the strain cloud diagram of the stress-strain field, the method further includes:

[0095] Acquire a first strain nephogram of the stress-strain field and a second strain nephogram generated by the initial finite element pipeline model corresponding to the first strain nephogram;

[0096] Comparing the accuracy of the first strain nephogram and the second strain nephogram, and determining whether the comparison result is greater than an accuracy threshold;

[0097] If so, it is determined that the initial finite element pipeline model meets the accuracy condition; otherwise, the initial finite element pipeline model is adjusted until the initial finite element pipeline model meets the accuracy condition.

[0098] This embodiment is applied before model accuracy verification, that is, after the initial finite element pipeline model is constructed, and the above steps are also used to obtain the first strain contour and the second strain contour. The two contours are then compared for accuracy. If the comparison accuracy is greater than the accuracy threshold (for example, the accuracy threshold is set to 95%), when the comparison result is greater than 95%, the model is considered to meet the accuracy requirements. Otherwise, the model's material partitioning and mesh parameters need to be further refined to improve the model's accuracy. After ensuring the accuracy of the model data, the model can be subjected to the above-mentioned accuracy verification. The advantage of this approach is that, since pipeline inspection and data collection are not implemented immediately after construction, the parameters used in model construction are not lifecycle parameters. By comparing the accuracy of the actual contour and the simulated contour, the accuracy between the finite element simulation results and the data obtained from actual monitoring using digital imaging technology can be determined. By ensuring the accuracy of the model data, the accuracy of degradation prediction using the model can be further improved. In cases where the accuracy requirements are met but the precision requirements are not met, the model's mesh parameters are considered accurate. In this case, the model's material partitioning needs to be refined and adjusted to ensure that the model meets the precision requirements.

[0099] In addition, in another preferred embodiment, the steps for constructing pipeline models with different aging degrees are further differentiated. The specific steps are:

[0100] Before determining the accuracy of the initial finite element pipeline model based on the strain cloud diagram of the stress-strain field, the method further includes:

[0101] Determining whether the initial longitudinal deformation of the pipeline to be inspected is greater than an aging threshold;

[0102] If yes, then the mechanical properties simulation test of the initial finite element pipeline model is performed to obtain the simulated mechanical parameters and simulated strain cloud diagram of the pipeline to be tested;

[0103] Dividing the pipeline to be inspected into regions, and dividing each region into sub-regions according to the simulated strain cloud map;

[0104] generating a reduction coefficient for each sub-region according to the area of ​​each sub-region and the corresponding simulation mechanical parameter;

[0105] According to the reduction coefficient, the initial finite element pipeline model is subjected to a partitioned constitutive reduction.

[0106] This embodiment is also applied before the accuracy verification of the model is performed, and if the accuracy verification of the model is also performed, this embodiment is applied after the accuracy verification and before the accuracy verification.

[0107] If digital imaging technology is used to monitor data and construct a corresponding finite element pipeline model during pipeline laying or normal use, the pipeline aging process can actually be truly reflected in the monitoring data and pipeline model. However, in reality, in most cases, pipeline inspection and data collection are not implemented immediately after construction. Therefore, it is necessary to perform constitutive reduction on the constructed pipeline model based on the degree of pipeline aging to improve the accuracy of model simulation.

[0108] Specifically, the aging degree of the pipeline to be tested is first determined, that is, whether the pipeline is elastically deformed or plastically deformed. Due to the irreversibility of plastic deformation, a plastically deformed pipeline is an aged pipeline and requires constitutive reduction. Therefore, in this embodiment, the initial longitudinal deformation of the pipeline to be tested is compared with an aging threshold to determine whether constitutive reduction is required. Preferably, the aging threshold can be set as a percentage of the pipeline diameter, such as 1% of the pipeline diameter. The specific threshold can be flexibly set according to actual conditions and is not excessively restricted here.

[0109] Referring to FIG5 , for pipelines to be inspected that have reached the aging threshold, mechanical properties simulation experiments are first performed on the initial finite element pipeline model to obtain simulated mechanical parameters and simulated strain cloud maps, such as stiffness SDEG, tensile damage value DT, and compressive damage value DC. The pipeline is then divided into regions. In this embodiment, the regions are divided according to the degree of danger of the pipeline, into four regions: the pipe top, the left arch line, the pipe bottom, and the right arch line. Each region is then divided into sub-regions based on the simulated strain cloud map. Taking the pipe bottom region as an example, the regions in the layered color-coded cloud map of the region with damage levels greater than the damage threshold are counted. For example, a stiffness SDEG of 1 indicates complete damage, while a stiffness SDEG of 0.8 indicates partial damage. Assuming stiffness SDEG is used as the standard, regions with damage levels greater than 80% are selected. Based on the different colors corresponding to different strain values ​​in the cloud map, the damaged region is then divided into multiple sub-regions based on color, i.e., stiffness value, such as the R (red) sub-region, the O (orange) sub-region, and the OL (orange-red) sub-region in FIG5 . The area A of each sub-region is then calculated. R 、A O and A OL , and the stiffness SDEG reduction weight value μ corresponding to each sub-area R 、μ O and μ OL , and the reduction coefficient of the bottom area is obtained as follows: h=(μ R A R +μ O A O +μ OL A OL ) / ∑μ i A i

[0110] According to the color spectrum setting interval of the cloud map in the finite element model, it is set to 13 levels from red to blue, μ i is the average threshold of different layered color cloud intervals, i represents the level, A i To obtain the area within the average threshold range.

[0111] After obtaining the reduction coefficient, the initial finite element pipeline model can be subjected to partitioned constitutive reduction, thereby further improving the accuracy of the model. After the constitutive reduction, if the model fails the accuracy test, the model adjustment is targeted at the constitutive reduction part, that is, the regional division of the pipeline is refined. Through more detailed regional division, the partitioned constitutive reduction is re-performed to achieve the adjustment of the model. It should be noted that the above reduction is only based on the stiffness SEDG parameter as an example. In fact, the partitioned constitutive reduction can also be performed by generating reduction coefficients using parameters such as the tensile damage value DT and the compressive damage value DC. Since the concrete adopts the CDP model, the elastic modulus, tensile constitutive coefficient, and compressive constitutive coefficient of the concrete can be reduced by the reduction coefficients generated in the above steps. Based on the same principle, the reduction coefficient can also be generated based on the deformation to perform deformation-based strength reduction on the steel bar. Here, one or more reduction methods can be selected according to the specific situation. Furthermore, the partitioned modeling can be performed based on the collected constitutive data of the aged concrete pipe specimen experiment. The specific steps can refer to the conventional partitioned modeling method and will not be repeated here.

[0112] Step S40 : generating a typical load-displacement curve of the pipeline to be inspected based on the finite element pipeline model, and calculating a degradation degree index of the pipeline to be inspected based on the typical load-displacement curve.

[0113] After building a finite element pipeline model that meets the accuracy requirements, the pipeline degradation degree can be predicted based on the typical load-displacement curve of the pipeline to be tested generated by the model. The specific steps are as follows:

[0114] Step S401, converting the typical load-displacement curve into a segmented model according to the load-displacement relationship;

[0115] Step S402: selecting a corresponding segmented expression from the segmented model according to a comparison result between the current longitudinal deformation of the pipeline to be tested and the limit displacement in the typical load-displacement curve;

[0116] Step S403: Calculate the residual strength of the pipeline to be inspected according to the segmented expression, and use the residual strength as an indicator of the degree of deterioration of the pipeline to be inspected.

[0117] Please refer to Figure 6. The typical load-displacement curve of reinforced concrete pipe failure is divided into two parts, namely the load-displacement relationship before the peak and the load-displacement relationship after the peak. According to the load-displacement relationship, the curve can be simplified into a three-segment line model:

[0118] Where, d x Indicates the displacement value, F(d x ) represents the load corresponding to the displacement value, k i represents the slope of the i-th segment, b and c are the intercepts of the second and third segments on the y-axis, respectively, and d c and d u d x endpoint value.

[0119] Taking the peak value of the curve as the dividing line, when the current longitudinal deformation D of the pipeline to be tested is less than the limit displacement d u When the residual strength p m for:

[0120] When the current longitudinal deformation D of the pipeline to be tested is greater than or equal to the limit displacement d u When the residual strength p n For: p n (d x )=(k3d x +c) / F u d u ≤d x

[0121] By taking the residual strength of the pipeline to be inspected as an indicator of the degree of deterioration, the deterioration detection of the pipeline is achieved.

[0122] For a more detailed description of the degradation detection method provided by the present invention, please refer to FIG7 . In this embodiment, digital imaging technology (DIC) is used for photographic analysis to construct strain field information inside the pipeline. Specifically, detection marker patches are arranged inside the pipeline, a binocular camera is installed and calibrated, and image acquisition is performed using an image acquisition strategy. The images are matched and tracked using an image processing algorithm to obtain the stress and strain field of the pipeline inner wall. A refined three-dimensional finite element pipeline model of the aged pipeline structure damage is constructed. Specifically, basic mechanical property test data of the original pipeline structural material and basic property data of the overlying soil sample are obtained as model parameters. A three-dimensional soil model is established according to the Mohr-Coulomb theory. A reinforced concrete structure model of the CDP model and the ideal elastic-plastic model is established. The external load conditions and boundary conditions are clarified, the traffic load is equivalently calculated according to the 20T standard, and the soil load is determined based on experimental parameters and survey data, thereby constructing an initial finite element pipeline model.

[0123] The accuracy of the internal strain cloud map of the pipeline monitored by DIC technology using the stress-strain field is compared with the corresponding three-dimensional strain cloud map of the pipe wall obtained using the initial finite element pipeline model. If the accuracy is greater than 95%, the model is considered to meet the accuracy requirements. Otherwise, the initial finite element pipeline model needs to be adjusted until the model meets the accuracy requirements, and then the damaged pipeline structure can be quantified.

[0124] For initial finite element pipelines that meet accuracy requirements, basic mechanical property testing is performed. Based on the generated mechanical parameters and strain contours, the reduction factor for each partition is calculated by statistically analyzing areas with damage levels greater than 80%. The elastic modulus, tensile damage, and compressive damage of the concrete are then reduced, and the steel bars are subjected to deformation-based strength reduction. This results in a reduced initial finite element pipeline model. A three-dimensional strain contour is generated based on model simulation, along with its corresponding strain contour generated from DIC imaging and analysis of the internal strain field information of the pipeline. The accuracy of the model is verified by the error between the two contours. If the accuracy requirements are not met, the regional division of the constitutive reduction needs to be adjusted, and the model accuracy is improved by re-performing the constitutive reduction until the model meets the accuracy requirements. Finally, the finite element pipeline model is obtained. Finally, the structural damage level of the pipeline is quantified using the highly accurate finite element pipeline model. That is, the degradation index of the pipeline to be tested is obtained through typical load-displacement curves, thereby achieving pipeline degradation detection.

[0125] This embodiment provides a reinforced concrete pipeline degradation detection method. Compared to traditional methods that can only perform local detection of aging structures and cannot fully reflect the extent of structural damage, the present invention integrates digital imaging technology with finite element technology to establish a reliable and refined three-dimensional pipeline model using a limited set of detection images. This enables accurate and efficient pipeline degradation detection, thereby achieving characterization and evaluation of damage occurrence, development, and evolution throughout the pipeline life cycle, further improving the operational and maintenance safety of the pipeline network system.

[0126] Referring to FIG8 , based on the same inventive concept, a second embodiment of the present invention proposes a reinforced concrete pipe deterioration detection system, comprising:

[0127] The model building module 10 is used to build an initial finite element pipeline model according to the pipeline parameters of the pipeline to be inspected;

[0128] The strain field construction module 20 is used to construct the stress and strain field of the pipeline to be inspected using digital imaging technology;

[0129] A model adjustment module 30 is configured to determine the accuracy of the initial finite element pipeline model based on the strain contour of the stress-strain field, and to adjust the initial finite element pipeline model based on the determination result to obtain a finite element pipeline model;

[0130] The index calculation module 40 is used to generate a typical load-displacement curve of the pipeline to be inspected based on the finite element pipeline model, and calculate a degradation degree index of the pipeline to be inspected based on the typical load-displacement curve.

[0131] The technical features and effects of the reinforced concrete pipe deterioration detection system proposed in the embodiments of the present invention are the same as those of the method proposed in the embodiments of the present invention and are not further elaborated here. Each module in the aforementioned reinforced concrete pipe deterioration detection system can be implemented in whole or in part through software, hardware, or a combination thereof. Each of these modules can be embedded in or independent of a processor in a computer device in hardware form, or stored in a computer device's memory in software form, allowing the processor to call and execute the corresponding operations of each module.

[0132] Please refer to Figure 9, which shows the internal structure of a computer device in one embodiment. The computer device can specifically be a terminal or server. The computer device includes a processor, memory, a network interface, a display, and an input device connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and computer program in the non-volatile storage medium. The network interface of the computer device is used to communicate with an external terminal via a network connection. When the computer program is executed by the processor, the method for detecting deterioration of reinforced concrete pipes is implemented. The display screen of the computer device can be a liquid crystal display or an electronic ink display. The input device of the computer device can be a touch layer covering the display screen, or it can be a key, trackball, or touchpad provided on the computer device housing, or it can be an external keyboard, touchpad, or mouse.

[0133] Those skilled in the art will understand that the structure shown in FIG9 is merely a block diagram of a portion of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computing device may include more or fewer components than those shown in the figure, or combine certain components, or have the same component arrangement.

[0134] In addition, an embodiment of the present invention further provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the computer program.

[0135] In addition, an embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of the above method when the computer program is executed by a processor.

[0136] In summary, the reinforced concrete pipe deterioration detection method, system, device and storage medium proposed in the embodiments of the present invention, the method constructs an initial finite element pipe model based on the pipe parameters of the pipe to be detected; uses digital image technology to construct the stress-strain field of the pipe to be detected; determines the accuracy of the initial finite element pipe model based on the strain cloud map of the stress-strain field, adjusts the initial finite element pipe model based on the determination result, and obtains a finite element pipe model; generates a typical load-displacement curve of the pipe to be detected based on the finite element pipe model, and calculates the degradation degree index of the pipe to be detected based on the typical load-displacement curve. The present invention integrates digital image technology with finite element technology. By establishing a high-precision finite element model, it can comprehensively reflect the degree of damage to the structure and accurately characterize the deterioration of the long-term operating structure in real time, thereby improving the operation and maintenance safety of the pipeline system.

[0137] Each embodiment in this specification is described in a progressive manner, and the same or similar parts of each embodiment can be directly referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. It should be noted that the various technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the various technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0138] The above-described embodiments merely represent several preferred implementations of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art could make several improvements and substitutions without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be based on the scope of protection of the claims.

Claims

1. A reinforced concrete pipe deterioration detection method, characterized in that: include: According to the pipeline parameters of the pipeline to be inspected, an initial finite element pipeline model is constructed; Using digital image technology to construct the stress and strain field of the pipeline to be inspected; According to the strain cloud diagram of the stress-strain field, the accuracy of the initial finite element pipeline model is determined, and according to the determination result, the initial finite element pipeline model is adjusted to obtain a finite element pipeline model; A typical load-displacement curve of the pipeline to be inspected is generated according to the finite element pipeline model, and a degradation degree index of the pipeline to be inspected is calculated according to the typical load-displacement curve.

2. The reinforced concrete pipe deterioration detection method according to claim 1, characterized in that: The step of using digital image technology to construct the stress and strain field of the pipeline to be inspected includes: Acquire time-series images of the inner wall of the pipeline to be inspected by using a binocular camera; Mapping and transforming the pixel coordinates of the time-series image, and traversing the pixels of the time-series image after the mapping and transformation to obtain an image displacement relationship; According to the image displacement relationship, the strain value of each pixel point is calculated, and the stress-strain field of the pipeline to be inspected is generated according to the strain value.

3. The reinforced concrete pipe deterioration detection method according to claim 1, characterized in that: The step of determining the accuracy of the initial finite element pipeline model according to the strain cloud diagram of the stress-strain field, and adjusting the initial finite element pipeline model according to the determination result to obtain the finite element pipeline model comprises: Acquire a first strain nephogram of the stress-strain field and a second strain nephogram generated by the initial finite element pipeline model corresponding to the first strain nephogram; Converting the first strain cloud map and the second strain cloud map into a first distribution matrix and a second distribution matrix respectively through image binarization; Subtracting the second distribution matrix from the first distribution matrix to obtain a difference matrix, and respectively ratioing each element of the difference matrix with each element of the first distribution matrix to obtain a difference ratio matrix; Calculate the average value of the sum of each element in the difference ratio matrix, and determine whether the average value is less than the accuracy threshold; If yes, the initial finite element pipeline model is used as the finite element pipeline model; otherwise, the initial finite element pipeline model is adjusted until the finite element pipeline model is obtained.

4. The reinforced concrete pipe deterioration detection method according to claim 3, characterized in that: The step of obtaining a first strain nephogram of the stress-strain field and a second strain nephogram generated by the initial finite element pipeline model corresponding to the first strain nephogram comprises: Acquire the initial longitudinal deformation of the pipeline to be inspected, the first strain cloud map of the stress-strain field, and the first longitudinal deformation corresponding to the first strain cloud map; According to the initial longitudinal deformation and the first longitudinal deformation, a corresponding strain frame is selected from the strain cloud map generated by the initial finite element pipeline model, wherein the strain frame includes a first strain frame and a second strain frame; A strain increment is obtained according to an RGB difference between the first strain frame and the second strain frame, and a second strain cloud map is generated according to the strain increment.

5. The reinforced concrete pipe deterioration detection method according to claim 4, characterized in that: Before determining the accuracy of the initial finite element pipeline model according to the strain cloud diagram of the stress-strain field, the method further includes: Acquire a first strain nephogram of the stress-strain field and a second strain nephogram generated by the initial finite element pipeline model corresponding to the first strain nephogram; Comparing the accuracy of the first strain cloud map and the second strain cloud map, and determining whether the comparison result is greater than an accuracy threshold; If so, it is determined that the initial finite element pipeline model meets the accuracy condition. Otherwise, the initial finite element pipeline model is adjusted until the initial finite element pipeline model meets the accuracy condition.

6. The reinforced concrete pipe deterioration detection method according to claim 3, characterized in that: Before determining the accuracy of the initial finite element pipeline model according to the strain cloud diagram of the stress-strain field, the method further includes: Determining whether the initial longitudinal deformation of the pipeline to be detected is greater than an aging threshold; If yes, then the simulated mechanical parameters and simulated strain cloud diagram of the pipeline to be tested are obtained by mechanical property simulation test of the initial finite element pipeline model; Dividing the pipeline to be inspected into regions, and dividing each region into sub-regions according to the simulated strain cloud map; Generate a reduction coefficient of each sub-region according to the area of ​​each sub-region and the corresponding simulation mechanical parameter; According to the reduction coefficient, the initial finite element pipeline model is subjected to a partitioned constitutive reduction.

7. The reinforced concrete pipe deterioration detection method according to claim 1, characterized in that: The step of calculating the degradation index of the pipeline to be inspected according to the typical load-displacement curve comprises: According to the load-displacement relationship, the typical load-displacement curve is converted into a segmented model; According to the comparison result of the current longitudinal deformation of the pipeline to be tested and the limit displacement in the typical load-displacement curve, a corresponding segmented expression is selected from the segmented model; According to the segmented expression, the residual strength of the pipeline to be inspected is calculated, and the residual strength is used as an indicator of the degree of deterioration of the pipeline to be inspected.

8. A reinforced concrete pipeline deterioration detection system, characterized in that: include: A model building module, used for building an initial finite element pipeline model according to pipeline parameters of the pipeline to be inspected; A strain field construction module, used to construct the stress strain field of the pipeline to be inspected by using digital image technology; A model adjustment module, used to judge the accuracy of the initial finite element pipeline model according to the strain cloud diagram of the stress-strain field, and adjust the initial finite element pipeline model according to the judgment result to obtain a finite element pipeline model; The index calculation module is used to generate a typical load-displacement curve of the pipeline to be detected according to the finite element pipeline model, and calculate the degradation degree index of the pipeline to be detected according to the typical load-displacement curve.

9. A computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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