Roadbed structure health state assessment method and system
By discretizing wheel loads to generate a set of wave sources, calculating wave propagation time, determining wave coherence, and performing stress amplitude reduction or energy accumulation, the problem of closed detection and insufficient accuracy in traditional roadbed health assessment is solved, enabling rapid identification and accurate assessment of damage distribution across the entire area.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-09
- Publication Date
- 2026-03-13
AI Technical Summary
Traditional roadbed health assessment methods require engineers to conduct on-site inspections, which leads to road closures and prevents continuous coverage of the entire area. Furthermore, laboratory tests cannot accurately simulate complex dynamic responses, resulting in low assessment efficiency and insufficient accuracy.
By discretizing the wheel load to generate three-dimensional coordinate points, constructing a discrete wave source set, calculating the propagation time from the wave source to the volume element, determining the wave coherence, and performing stress amplitude reduction or energy accumulation, the dynamic stress field is simulated, and a risk distribution voxel map is generated.
It can obtain the full-area three-dimensional damage distribution without damaging the road surface, quickly identify potential risk areas, and improve the coverage and accuracy of roadbed health diagnosis.
Smart Images
Figure CN121656404A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of computer simulation verification technology, and in particular to a method and system for assessing the health status of roadbed structures. Background Technology
[0002] The field of computer simulation verification technology refers to the general technical category of constructing mathematical models of physical systems using digital computing equipment and simulating, analyzing, and verifying the mechanical behavior, functional characteristics, or operational status of technical systems through numerical calculation techniques. Among these methods, traditional roadbed structure health status assessment involves engineers carrying Benkelman beams or vehicle-mounted falling weight deflectometers to the road site. They apply standard loads and measure the rebound deflection values of the roadbed surface using displacement sensors, or use geological drilling rigs to drill core samples at specific pile numbers. The obtained soil samples are then sent to a laboratory where a pressure testing machine is used to determine their unconfined compressive strength and moisture content. Finally, the compaction degree and bearing capacity of the roadbed are determined based on the readings of on-site physical instruments and the laboratory measured data.
[0003] Traditional roadbed health assessments require engineers to bring equipment to the site or conduct destructive core sampling, forcing road closures and disrupting normal traffic. Physical single-point testing is limited by discrete sampling locations, making it difficult to achieve continuous coverage of the entire road area, resulting in blind spots. Furthermore, laboratory static testing cannot accurately reproduce the complex dynamic response of roadbed materials under continuous moving wheel loads, leading to deviations in the assessment of structural integrity under actual operating conditions. In large-scale road health inspections, this approach is inefficient and fails to generate an intuitive risk distribution mapping. Summary of the Invention
[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a method and system for assessing the health status of roadbed structures.
[0005] To achieve the above objectives, the present invention adopts the following technical solution: a method for assessing the health status of roadbed structures, comprising the following steps: S1: Obtain the position and speed of the detected wheel. Based on the preset time step parameters, generate the three-dimensional coordinate point of the wheel load center through discretization processing. Associate the three-dimensional coordinate point with the value of the instantaneous impact force of the wheel on the ground to construct a discrete wave source set. S2: Obtain the spatial geometric center coordinates of the volume unit, calculate the straight-line distance between the spatial geometric center coordinates and the three-dimensional coordinate points in the discrete wave source set, and divide the straight-line distance by the propagation speed to obtain the propagation time value; S3: Obtain the generation time of the wave source and add it to the propagation time value to obtain the absolute time value. Calculate the difference based on the minimum value of the absolute time value and compare the difference with the time threshold. S4: If the difference is less than the time threshold, it is defined as a coherent superposition group. The impact force value in the coherent superposition group is reduced and added together to obtain the composite stress amplitude. If the difference is greater than the time threshold, it is defined as an incoherent component and accumulated to obtain the energy of the incoherent component. S5: Combine the combined stress amplitude with the background stress obtained from the incoherent component energy to obtain the maximum equivalent dynamic stress. If the maximum equivalent dynamic stress is greater than the fatigue limit, mark the spatial geometric center coordinates as the damage point and form a risk distribution voxel map.
[0006] As a further aspect of the present invention, step S1 specifically comprises: S11: Obtain the position and speed of the detected wheel, combine it with the preset driving trajectory equation, establish a continuous movement path model including the time dimension through interpolation calculation, and extract the spatial vector data of the model at different times. S12: Based on the time step parameter, the spatial vector data is sampled at equal intervals, the spatial position of each sampling point in the roadbed coordinate system is analyzed, and three-dimensional coordinate points are generated; S13: Calculate the dynamic load coefficient based on the detected wheel speed, and combine it with the wheel static load data to calculate the instantaneous impact force corresponding to each of the three-dimensional coordinate points; S14: Encapsulate each of the three-dimensional coordinate points, the corresponding instantaneous impact force value, and the corresponding sampling time into an independent data unit, and traverse all sampling points to construct a discrete wave source set.
[0007] As a further aspect of the present invention, step S2 specifically comprises: S21: Perform three-dimensional meshing on the target roadbed structure area to generate several volume elements, and extract the geometric centroid of each volume element as the spatial geometric center coordinates; S22: Construct a Euclidean distance calculation matrix, calculate the vector magnitude between the coordinates of the spatial geometric center and each of the three-dimensional coordinate points in the discrete wave source set, and generate the straight-line distance; S23: Obtain the physical property parameters of the roadbed medium and determine the propagation speed based on the propagation characteristics of elastic waves in the medium; S24: Divide the straight-line distance by the propagation speed to calculate the time required for the elastic wave to propagate from the wave source to the volume unit, and obtain the propagation time value.
[0008] As a further aspect of the present invention, step S3 specifically comprises: S31: Extract the generation time of the wave source from the discrete wave source set, add it to the corresponding propagation time value by scalar to obtain the absolute time value of the elastic wave arriving at the volume unit. S32: Traverse all the absolute time values for the same volume unit and select the time point with the smallest value as the baseline arrival time; S33: Subtract the reference arrival time from each of the absolute time values to calculate the difference representing the dispersion of the wavefront arrival time, and compare the difference with a preset time threshold.
[0009] As a further aspect of the present invention, step S4 specifically comprises: S41: Filter all wave source items with a difference less than the time threshold and classify them as coherent superposition groups; filter all wave source items with a difference greater than the time threshold and classify them as incoherent components. S42: Obtain the medium damping coefficient and geometric diffusion factor, calculate the reduction of the impact force value in the coherent superposition group using a preset wave field attenuation formula, and vector superimpose the reduced stress components to generate a composite stress amplitude. The wave field attenuation formula is as follows: ; in, Represents the combined stress amplitude. Representing the The impact force value of each wave source, Representing the The straight-line distances corresponding to each wave source Represents the geometric diffusion factor. Represents the medium damping coefficient. This represents the total number of wave sources within a coherent superposition group; S43: Perform energy conversion on each wave source in the incoherent component, calculate the square term of its stress amplitude and perform scalar accumulation, and obtain the energy of the incoherent component by taking the square root of the accumulation result.
[0010] As a further aspect of the present invention, step S5 specifically comprises: S51: The combined stress amplitude and the incoherent component energy are weighted and combined to generate the background stress that reflects the background vibration intensity inside the subgrade, and the maximum equivalent dynamic stress is calculated by combining the static load stress of the subgrade. S52: Obtain the SN fatigue curve parameters of the roadbed material, calculate the upper limit of the allowable stress of the material under the current state based on the current loading frequency and service cycle, and set it as the fatigue limit; S53: Compare the maximum equivalent dynamic stress with the fatigue limit. If the former is greater than the latter, it is determined that the current volume element has a risk of structural failure, and its spatial geometric center coordinates are marked as the damage point. S54: Traverse all volumetric elements in the subgrade structure, assign high-risk label values to elements marked as damage points, assign low-risk label values to the remaining elements, construct a three-dimensional matrix, and form a risk distribution voxel map.
[0011] As a further aspect of the present invention, the background stress calculation process of S51 includes: Obtain the coherent weighting factor and the incoherent weighting factor, multiply the combined stress amplitude by the coherent weighting factor to obtain the main wave field stress, and multiply the incoherent component energy by the incoherent weighting factor to obtain the scattered field stress. The background stress is generated by linearly superimposing the main wave field stress and the scattered field stress.
[0012] As a further aspect of the present invention, the voxel map formation process of S54 includes: Establish a three-dimensional Cartesian coordinate system that is consistent with the physical dimensions of the roadbed, and map all volume units to the coordinate system according to their spatial geometric center coordinates; Based on the ratio of the maximum equivalent dynamic stress to the fatigue limit, a corresponding color level value or transparency parameter is assigned to each damage point, and a visualized risk distribution voxel map is generated.
[0013] As a further aspect of the present invention, the time step parameter determination process of S12 includes: Acquire the data sampling frequency of the detection sensor and the cutoff frequency of the high-frequency vibration of the wheel; Based on the Nyquist sampling theorem, the minimum time interval that can completely reconstruct the characteristics of the wheel impact signal is calculated and set as the time step parameter.
[0014] A roadbed structure health status assessment system, the roadbed structure health status assessment system being used to implement the above-mentioned roadbed structure health status assessment method, the system comprising: The impact source discretization module is used to obtain the position and speed of the detected wheel. Based on the preset time step parameters, it generates three-dimensional coordinate points of the wheel load center through discretization processing. It associates the three-dimensional coordinate points with the value of the instantaneous impact force of the wheel on the ground to construct a set of discrete wave sources and transmits them to the wave path transmission analysis module. The path propagation analysis module is used to obtain the spatial geometric center coordinates of the volume unit, calculate the straight-line distance between the spatial geometric center coordinates and the three-dimensional coordinate points in the discrete wave source set, divide the straight-line distance by the propagation speed to obtain the propagation time value, and transmit it to the time difference comparison module. The time difference comparison module is used to obtain the generation time of the wave source and add it to the propagation time value to obtain the absolute time value. Based on the minimum value of the absolute time value, the difference is calculated, the difference is compared with the time threshold, and then transmitted to the wave field superposition processing module. The wave field superposition processing module is used to determine the coherent superposition group if the difference is less than the time threshold, subtract the impact force value in the coherent superposition group and add them to obtain the composite stress amplitude, and determine the incoherent component if the difference is greater than the time threshold, and accumulate the incoherent component energy, and then transmit the composite stress amplitude and the incoherent component energy to the structural fatigue diagnosis module. The structural fatigue diagnosis module is used to combine the synthetic stress amplitude with the background stress obtained by the incoherent component energy to obtain the maximum equivalent dynamic stress. If the maximum equivalent dynamic stress is greater than the fatigue limit, the spatial geometric center coordinates are marked as the damage point and a risk distribution voxel map is formed.
[0015] Compared with the prior art, the advantages and positive effects of the present invention are as follows: In this invention, the trajectory of wheel motion is discretized into a set of wave sources with spatiotemporal attributes. The propagation delay from the wave source to the spatial volume unit is calculated to construct a dynamic stress field. The coherence of the wave is determined based on the time threshold, and stress amplitude reduction and superposition or incoherent energy accumulation are performed respectively. The transient maximum equivalent dynamic stress generated by the moving load inside the roadbed is accurately simulated. The three-dimensional damage distribution of the entire area can be obtained without damaging the road surface. Potential risk areas are quickly identified based on the fatigue limit threshold and an intuitive voxel map is generated, which effectively improves the coverage and assessment accuracy of roadbed health diagnosis. Attached Figure Description
[0016] Figure 1 This is the main flowchart of the roadbed structure health status assessment method of the present invention; Figure 2 This is a flowchart illustrating the construction process of the discrete wave source set in this invention. Figure 3 This is a flowchart illustrating the calculation of elastic wave propagation time according to the present invention. Figure 4 This is a flowchart of the wavefront arrival time difference analysis of the present invention; Figure 5 This is a flowchart of the stress component separation and energy calculation process of the present invention; Figure 6 This is a flowchart of the risk distribution voxel map generation process of the present invention. Detailed Implementation
[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the software-based technical solution is described in detail below with reference to system architecture diagrams and embodiments. It should be understood that the specific embodiments described herein are only for explaining the technical solutions of this invention and do not constitute a limitation on the scope of protection.
[0018] In the description of this invention, the system architecture relationships or data processing flows indicated by terms such as "layer," "module," "interface," "data flow," "client," and "server" are all defined based on the architecture diagram or flowchart corresponding to the embodiments. This way of describing is only used to clearly illustrate the logical relationships between the elements in the technical solution, and not to limit the physical deployment form. The term "multiple" includes two or more technical units, including but not limited to multiple data nodes, processing threads, service instances, or functional components and other scalable elements. The specific number is determined according to the actual business scenario and needs to be specifically specified.
[0019] Please see Figure 1 and Figure 2 This invention provides a technical solution: a method for assessing the health status of roadbed structures, comprising the following steps: S1: Obtain the position and speed of the detected wheel. Based on the preset time step parameters, generate the three-dimensional coordinate point of the wheel load center through discretization. Associate the three-dimensional coordinate point with the value of the instantaneous impact force of the wheel on the ground to construct a set of discrete wave sources. The specific steps of S1 are as follows: S11: Obtain the position and speed of the detected wheels, combine them with the preset driving trajectory equation, establish a continuous movement path model including the time dimension through interpolation, and extract the spatial vector data of the model at different times. S12: Based on the time step parameter, the spatial vector data is sampled at equal intervals, the spatial position of each sampling point in the roadbed coordinate system is analyzed, and three-dimensional coordinate points are generated; The process of determining the time step parameter of S12 includes: Acquire the data sampling frequency of the detection sensor and the cutoff frequency of the high-frequency vibration of the wheel; Based on the Nyquist sampling theorem, the minimum time interval that can completely reconstruct the characteristics of the wheel impact signal is calculated and set as the time step parameter; S13: Calculate the dynamic load coefficient based on the detected wheel speed, and combine it with the wheel static load data to calculate the instantaneous impact force corresponding to each three-dimensional coordinate point; S14: Encapsulate each three-dimensional coordinate point, the corresponding instantaneous impact force value, and the corresponding sampling time into an independent data unit, and traverse all sampling points to construct a discrete wave source set.
[0020] This embodiment selects a 100-meter-long and 10-meter-wide section of highway subgrade as the inspection object. A three-dimensional coordinate system for the subgrade structure is established, with the origin located at the center of the road surface at the starting end of the subgrade. The X-axis is along the driving direction, the Y-axis is perpendicular to the driving direction, and the Z-axis is vertically downward. The inspection vehicle is equipped with a high-precision GPS positioning system and wheel force sensors. In stage S11, the onboard sensors collect the spatial position coordinates and instantaneous velocity vectors of the inspected wheels in real time at a frequency of 1000Hz. In this embodiment, the inspection vehicle travels at a constant speed along the X-axis, and at time... Time is located at coordinates Wheel speed Constant as The vehicle trajectory equation is set as a linear equation. ,in This is the initial position vector. The system extracts... to This is a continuous movement path model within a certain time period, which includes a time dimension and the corresponding spatial vector data sequence.
[0021] In stage S12, the time step parameter is determined according to the Nyquist sampling theorem. The sampling frequency of the vehicle force sensor is known. The effective cutoff frequency for high-frequency impact vibration of the wheel on the ground was determined to be 2000 Hz through spectral analysis. The minimum sampling frequency is 200Hz. According to the sampling theorem, to avoid aliasing and fully reconstruct signal characteristics, the minimum sampling frequency must be greater than... That is, 400Hz. The minimum time interval for the system to calculate and fully reconstruct the signal characteristics. To improve evaluation accuracy, this embodiment uses the time step parameter. Set as That is, a sampling frequency of 500Hz. The system is based on... Regarding the above Spatial vector data of duration are sampled at equal intervals, generating a total of 50 sampling points. For the first... sampling points ( ), its sampling time The system analyzes the three-dimensional coordinates of the roadbed coordinate system at that moment. .when hour, ,coordinate for ;when hour, ,coordinate for .
[0022] In phase S13, the system reads wheel static load data. According to the testing specifications, based on wheel speed... Calculate the dynamic load factor. This example uses an empirical formula. Calculated The system calculates the instantaneous impact force corresponding to each three-dimensional coordinate point. ,in The random disturbance factor caused by road surface unevenness fluctuates between 0.95 and 1.05.
[0023] Taking the first sampling point as an example, the actual measurement ,but ; Taking the second sampling point as an example, the actual measurement... ,but .
[0024] In stage S14, the system constructs a discrete wave source set. The system allocates memory space to store the calculated sampling times. 3D coordinate points and instantaneous impact force value Encapsulated as a structured data unit The above 50 sampling points are iterated through, and the data units are sequentially stored in the discrete source set list. Table 1 lists some of the data items in the discrete source set; As shown in Table 1, the discrete wave source set accurately records the distribution of wheel load in time and space, providing basic wave source data for subsequent elastic wave propagation calculations.
[0025] The aforementioned continuous movement path model refers to a set of mathematical functions constructed using kinematic interpolation algorithms based on discrete vehicle position monitoring points to describe the spatial position of a vehicle at any point in time, used to characterize the continuous movement trajectory of the vehicle load in time and space.
[0026] Please see Figure 1 and Figure 3 S2: Obtain the spatial geometric center coordinates of the volume element, calculate the straight-line distance between the spatial geometric center coordinates and the three-dimensional coordinate points in the discrete wave source set, and divide the straight-line distance by the propagation speed to obtain the propagation time value; The specific steps of S2 are as follows: S21: Perform three-dimensional meshing on the target roadbed structure area to generate several volume elements, and extract the geometric centroid of each volume element as the coordinates of the spatial geometric center. S22: Construct the Euclidean distance calculation matrix, calculate the vector magnitude between the coordinates of the spatial geometric center and each three-dimensional coordinate point in the discrete wave source set, and generate the straight-line distance; S23: Obtain the physical property parameters of the roadbed medium and determine the propagation speed based on the propagation characteristics of elastic waves in the medium; S24: Divide the straight-line distance by the propagation speed to calculate the time required for the elastic wave to propagate from the wave source to the volume element, and obtain the propagation time value.
[0027] In phase S21, the system performs finite element mesh generation for the deep region of the roadbed structure. The target region is defined as the compacted soil layer 5 meters below the pavement, and eight-node hexahedral elements are used for meshing. The system selects one volume element to be evaluated. Extract the coordinates of all its nodes and take the average value to calculate the geometric centroid coordinates of the volume element. In this embodiment, the geometric centroid coordinates of the volume element are: The unit is meters.
[0028] In phase S22, the system retrieves the discrete wave source set data generated in S1. It constructs a Euclidean distance calculation matrix for each wave source point in the set. Calculate its relationship with the geometric centroid of the volume element. The straight-line distance between The distance calculation formula is: .
[0029] Substitute the data from S1 into the specific calculations: For wave source 1 ( ), ; For wave source 2 ( ), .
[0030] The system iterates through all 50 wave source points according to this logic, generating the corresponding linear distance sequence.
[0031] In stage S23, the system queries the database of physical property parameters of the subgrade medium. The subgrade fill material is compacted silt, and its elastic modulus is... The determination is as (Right now ), medium density for Poisson's ratio The value is 0.3. The system calculates the propagation velocity of the longitudinal wave (P-wave) based on the elastic wave propagation theory. The calculation formula is: .
[0032] Substitute the parameters into the calculation: The numerator is ; The denominator term is ; Calculation results ; The system locks the propagation speed to [value]. .
[0033] In phase S24, the system utilizes propagation speed Divide the linear distance sequence to obtain the propagation time value. .
[0034] Calculate the propagation time of wave source 1 ; Calculate the propagation time of wave source 2 .
[0035] The system will assign the propagation time value to each wave source. Store the data in a temporary array and associate it with the original wave source number to complete the time quantization of the physical transmission process.
[0036] The aforementioned volume element refers to the smallest analytical unit with specific geometric shape and physical properties generated by three-dimensional mesh generation technology in the finite element model of the roadbed structure, used to characterize the local mechanical behavior of the continuous medium inside the roadbed.
[0037] Please see Figure 1 and Figure 4 S3: Obtain the generation time of the wave source and add it to the propagation time value to obtain the absolute time value. Calculate the difference based on the minimum value of the absolute time value and compare the difference with the time threshold. The specific steps for S3 are as follows: S31: Extract the generation time of the wave source from the discrete wave source set, add it to the corresponding propagation time value by scalar to obtain the absolute time value of the elastic wave arriving at the volume element. S32: Iterate through all absolute time values for the same volume unit and select the time point with the smallest value as the baseline arrival time; S33: Subtract the reference arrival time from each absolute time value to calculate the difference representing the dispersion of wavefront arrival time, and compare the difference with a preset time threshold.
[0038] In stage S31, the system extracts the generation times of wave sources from the discrete wave source set. And compared with the propagation time value calculated in S2 Perform scalar addition to calculate the volume element where the elastic wave arrives. absolute time value .
[0039] For wave source 1, the generation time is... Dissemination time absolute moment ; For wave source 2, the generation time Dissemination time absolute moment .
[0040] For wave source 3 ( ,distance Dissemination time ), absolute moment .
[0041] In phase S32, the system targets volumetric elements. All 50 absolute time values Perform a sorting and traversal process to select the time point with the smallest value as the baseline arrival time. In this embodiment, since the vehicle speed is much lower than the wave speed, the earliest generated wave source arrives first, and the minimum value obtained after filtering is... (Right now ).
[0042] In phase S33, the system sets a time threshold. The time threshold is determined based on the period of the main vibration frequency. 1 / 4. Given that the dominant impact frequency is 50Hz, then the period... Set time threshold The system will display the values at each absolute moment. Subtract the base arrival time Calculate the difference .
[0043] Calculate the difference of wave source 1 ; Calculate the difference of wave source 2 ; Calculate the difference of wave source 3 .
[0044] The system compares these differences with a threshold. Compare: , , .
[0045] Assuming there exists a subsequent wave source ,That ,but Through this process, the system quantifies the temporal dispersion of different wave sources at the target location.
[0046] The aforementioned time threshold refers to the critical time parameter used to determine whether multiple elastic wave signals belong to the same coherent superposition time window. Its value is usually set according to the dominant frequency period of the elastic wave.
[0047] Please see Figure 1 and Figure 5S4: If the difference is less than the time threshold, it is defined as a coherent superposition group. The impact force value in the coherent superposition group is reduced and added together to obtain the composite stress amplitude. If the difference is greater than the time threshold, it is defined as an incoherent component and accumulated to obtain the energy of the incoherent component. The specific steps for S4 are as follows: S41: Filter all wave source items with a difference less than the time threshold and classify them as coherent superposition groups; filter all wave source items with a difference greater than the time threshold and classify them as incoherent components. S42: Obtain the medium damping coefficient and geometric diffusion factor, use the preset wave field attenuation formula to reduce the impact force value in the coherent superposition group, and then perform vector superposition of the reduced stress components to generate the composite stress amplitude. The wave field attenuation formula is as follows: ; in, Represents the combined stress amplitude. Representing the The impact force value of each wave source, Representing the The straight-line distances corresponding to each wave source Represents the geometric diffusion factor. Represents the medium damping coefficient. This represents the total number of wave sources within a coherent superposition group; S43: Perform energy conversion on each wave source in the incoherent component, calculate the square term of its stress amplitude and perform scalar accumulation, and obtain the energy of the incoherent component by taking the square root of the accumulation result.
[0048] In stage S41, the system classifies the data based on the comparison results from S3. The differences are then... Less than the time threshold Wave sources (such as wave sources 1, 2, and 3) are classified into coherent superposition groups. Wave sources with a difference greater than the time threshold (such as wave sources) ) classified as incoherent components According to system statistics, in this embodiment, a total of 8 wave sources enter the coherent superposition group, and the remaining 42 wave sources enter the incoherent component.
[0049] In phase S42, the system invokes the wavefield attenuation formula to process the coherent stack. The wavefield attenuation formula is: ; in, This represents the combined stress amplitude, with the unit being Pascals (Pa). Representing the The impact force of a wave source, expressed in Newtons (N). Representing the The straight-line distance between a wave source and a volume unit, in meters (m). Represents the geometric diffusion factor, which is used because waves inside the roadbed mainly propagate in the form of body waves. ; Represents the medium damping coefficient, with units of . The damping coefficient of the roadbed material was measured through on-site attenuation experiments. ; This represents the total number of wave sources within a coherent superposition group; This is the base of the natural logarithm. A practical example calculation is then performed (for demonstration purposes, only wave source 1 and wave source 2 are used to demonstrate the superposition calculation): For wave source 1, ; For wave source 2, .
[0050] Synthetic stress amplitude .
[0051] The results indicate that the wave source within the coherent time window generated a concentrated dynamic stress response of approximately 12.11 kPa at the target point.
[0052] In stage S43, energy conversion is performed on each wave source in the incoherent component. For the wave sources in the incoherent group... Let its attenuated single-wave stress amplitude be... for The system calculates its squared terms. The system iterates through all 42 wave sources in the incoherent group and accumulates their squared terms. In this embodiment, the accumulation result is: .
[0053] The system performs square root operations on the accumulated results: .
[0054] Obtain the energy of the incoherent component .
[0055] The aforementioned coherent superposition group refers to a subset of wave sources whose time difference in arriving at the target volume unit in the time domain is within a preset threshold range. The vibration response caused by the wave sources in this set at their spatial locations is considered to have a constructive interference effect.
[0056] Please see Figure 1 and Figure 6 S5: Combine the combined stress amplitude and the background stress obtained from the incoherent component energy to obtain the maximum equivalent dynamic stress. If the maximum equivalent dynamic stress is greater than the fatigue limit, mark the coordinates of the spatial geometric center as the damage point and form a risk distribution voxel map. The specific steps of S5 are as follows: S51: The combined stress amplitude and the energy of the incoherent components are weighted and combined to generate the background stress that reflects the intensity of the background vibration inside the subgrade, and the maximum equivalent dynamic stress is obtained by combining the static load stress of the subgrade. The calculation process for the background stress of S51 includes: Obtain the coherent weighting factor and the incoherent weighting factor, multiply the combined stress amplitude by the coherent weighting factor to obtain the main wave field stress, and multiply the incoherent component energy by the incoherent weighting factor to obtain the scattered field stress. The background stress is generated by linearly superimposing the main wave field stress and the scattered field stress. S52: Obtain the SN fatigue curve parameters of the subgrade material, calculate the upper limit of allowable stress of the material under the current state based on the current loading frequency and service cycle, and set it as the fatigue limit; S53: Compare the maximum equivalent dynamic stress with the fatigue limit numerically. If the former is greater than the latter, it is determined that the current volume element has a risk of structural failure, and its spatial geometric center coordinates are marked as the damage point. S54: Traverse all volumetric elements in the subgrade structure, assign high-risk label values to elements marked as damage points, and assign low-risk label values to the remaining elements, construct a three-dimensional matrix and form a risk distribution voxel map; The process of forming the voxel map of S54 includes: Establish a three-dimensional Cartesian coordinate system that is consistent with the physical dimensions of the roadbed, and map all volume units to the coordinate system according to their spatial geometric center coordinates; Based on the ratio of the maximum equivalent dynamic stress to the fatigue limit, a corresponding color level value or transparency parameter is assigned to each damage point, and a visualized risk distribution voxel map is generated.
[0057] In the S51 phase, the system calculates the maximum equivalent dynamic stress. First, the weighting factor is determined based on the measured waveform dominant frequency energy proportion from the field, setting the coherence weighting factor. (Considering the destructive enhancement effect of coherent waves), incoherent weighting factor Using the results from S4, the main wave field stress is calculated. ; Calculate the stress of the scattered field .
[0058] The two are superimposed to generate the background stress. .
[0059] The system obtains the static stress of the roadbed at this depth. It is generated by the weight of the overlying soil layer, at a depth of 5m, with a density of gravitational acceleration .
[0060] calculate .
[0061] The final calculation of the maximum equivalent dynamic stress .
[0062] In stage S52, the SN fatigue curve parameters of the subgrade material were obtained. The fatigue equation for this material is: In this embodiment, a material constant is used for compacted silty soil. To ensure that the calculation unit is consistent in kPa, material constants were set after laboratory calibration. (Derived value based on kPa unit system). The system reads the cumulative number of loads within the service life of this road section. Next, calculate the upper limit of allowable stress (fatigue limit) of the material under its current condition. : .
[0063] Calculation results .
[0064] In stage S53, the system performs numerical comparisons: the maximum equivalent dynamic stress is... Fatigue Limit Compare and determine. The result is true. Based on this, the system determines the current volume element. There is a risk of structural failure, and the coordinates Marked as damage points.
[0065] In the S54 phase, the system establishes a three-dimensional Cartesian coordinate system that is consistent with the physical dimensions of the roadbed. The system iterates through all 100,000 volumetric elements within the roadbed. For elements marked as damage points, their risk ratios are calculated. The system assigns color level values based on the risk ratio.
[0066] Set color level mapping rules: It is green (90% transparency). It is yellow. It is red.
[0067] For the cells in this example, the system assigns a yellow color value (RGB:255,255,0) and sets the opacity to 100%. The system writes the color and position data of all cells into a 3D matrix and calls the OpenGL graphics library to render and generate a voxel map of the visualized risk distribution. In this voxel map, the operator can clearly observe the coordinates. The area highlighted in yellow visually reveals the fatigue damage risk zone inside the roadbed.
[0068] The aforementioned risk distribution voxel map refers to a three-dimensional image reflecting the overall structural health of the roadbed, constructed by using three-dimensional voxel rendering technology to map the health status values of each volume unit inside the roadbed into visualized color or transparency parameters.
[0069] A roadbed structure health status assessment system, the roadbed structure health status assessment system being used to execute the above-described roadbed structure health status assessment method, the system comprising: The impact source discretization module is used to obtain the position and speed of the detected wheel. Based on the preset time step parameters, it generates the three-dimensional coordinate point of the wheel load center through discretization processing. It associates the three-dimensional coordinate point with the value of the instantaneous impact force of the wheel on the ground to construct a set of discrete wave sources and transmits it to the wave path transmission analysis module. The path propagation analysis module is used to obtain the spatial geometric center coordinates of the volume element, calculate the straight-line distance between the spatial geometric center coordinates and the three-dimensional coordinate points in the discrete wave source set, divide the straight-line distance by the propagation speed to obtain the propagation time value, and transmit it to the time difference comparison module. The time difference comparison module is used to obtain the generation time of the wave source and add it to the propagation time value to obtain the absolute time value. It calculates the difference based on the minimum value of the absolute time value, compares the difference with the time threshold, and transmits it to the wave field superposition processing module. The wave field superposition processing module is used to determine the coherent superposition group if the difference is less than the time threshold, subtract the impact force value in the coherent superposition group and add them to obtain the composite stress amplitude. If the difference is greater than the time threshold, it is determined to be an incoherent component and the incoherent component energy is accumulated. The composite stress amplitude and the incoherent component energy are then transferred to the structural fatigue diagnosis module. The structural fatigue diagnosis module is used to combine the background stress obtained by combining the synthetic stress amplitude and the incoherent component energy to obtain the maximum equivalent dynamic stress. If the maximum equivalent dynamic stress is greater than the fatigue limit, the spatial geometric center coordinates are marked as the damage point and a risk distribution voxel map is formed.
[0070] The above embodiments illustrate preferred embodiments of the present invention. Any equivalent adjustments to the technical solution based on software engineering methods are within the scope of protection, including but not limited to: implementing algorithm logic using different programming languages, refactoring functional modules into services, adjusting data interaction protocols, and optimizing resource scheduling strategies. Any implementation scheme derived from reasonable modifications to the data processing flow, service call chain, or system architecture layer without departing from the core technology of the present invention should be considered within the scope of protection of the present invention.
Claims
1. A method for assessing the health status of roadbed structures, characterized in that, Includes the following steps: S1: Obtain the position and speed of the detected wheel. Based on the preset time step parameters, generate the three-dimensional coordinate point of the wheel load center through discretization processing. Associate the three-dimensional coordinate point with the value of the instantaneous impact force of the wheel on the ground to construct a discrete wave source set. S2: Obtain the spatial geometric center coordinates of the volume unit, calculate the straight-line distance between the spatial geometric center coordinates and the three-dimensional coordinate points in the discrete wave source set, and divide the straight-line distance by the propagation speed to obtain the propagation time value; S3: Obtain the generation time of the wave source and add it to the propagation time value to obtain the absolute time value. Calculate the difference based on the minimum value of the absolute time value and compare the difference with the time threshold. S4: If the difference is less than the time threshold, it is defined as a coherent superposition group. The impact force value in the coherent superposition group is reduced and added together to obtain the composite stress amplitude. If the difference is greater than the time threshold, it is defined as an incoherent component and accumulated to obtain the energy of the incoherent component. S5: Combine the combined stress amplitude with the background stress obtained from the incoherent component energy to obtain the maximum equivalent dynamic stress. If the maximum equivalent dynamic stress is greater than the fatigue limit, mark the spatial geometric center coordinates as the damage point and form a risk distribution voxel map.
2. The method for assessing the health status of roadbed structures according to claim 1, characterized in that, The specific steps of S1 are as follows: S11: Obtain the position and speed of the detected wheel, combine it with the preset driving trajectory equation, establish a continuous movement path model including the time dimension through interpolation calculation, and extract the spatial vector data of the model at different times. S12: Based on the time step parameter, the spatial vector data is sampled at equal intervals, the spatial position of each sampling point in the roadbed coordinate system is analyzed, and three-dimensional coordinate points are generated; S13: Calculate the dynamic load coefficient based on the detected wheel speed, and combine it with the wheel static load data to calculate the instantaneous impact force corresponding to each of the three-dimensional coordinate points; S14: Encapsulate each of the three-dimensional coordinate points, the corresponding instantaneous impact force value, and the corresponding sampling time into an independent data unit, and traverse all sampling points to construct a discrete wave source set.
3. The method for assessing the health status of roadbed structures according to claim 2, characterized in that, The specific steps of S2 are as follows: S21: Perform three-dimensional meshing on the target roadbed structure area to generate several volume elements, and extract the geometric centroid of each volume element as the spatial geometric center coordinates; S22: Construct a Euclidean distance calculation matrix, calculate the vector magnitude between the coordinates of the spatial geometric center and each of the three-dimensional coordinate points in the discrete wave source set, and generate the straight-line distance; S23: Obtain the physical property parameters of the roadbed medium and determine the propagation speed based on the propagation characteristics of elastic waves in the medium; S24: Divide the straight-line distance by the propagation speed to calculate the time required for the elastic wave to propagate from the wave source to the volume unit, and obtain the propagation time value.
4. The method for assessing the health status of roadbed structures according to claim 3, characterized in that, The specific steps of S3 are as follows: S31: Extract the generation time of the wave source from the discrete wave source set, add it to the corresponding propagation time value by scalar to obtain the absolute time value of the elastic wave arriving at the volume unit. S32: Traverse all the absolute time values for the same volume unit and select the time point with the smallest value as the baseline arrival time; S33: Subtract the reference arrival time from each of the absolute time values to calculate the difference representing the dispersion of the wavefront arrival time, and compare the difference with a preset time threshold.
5. The method for assessing the health status of roadbed structures according to claim 4, characterized in that, The specific steps of S4 are as follows: S41: Filter all wave source items with a difference less than the time threshold and classify them as coherent superposition groups; filter all wave source items with a difference greater than the time threshold and classify them as incoherent components. S42: Obtain the medium damping coefficient and geometric diffusion factor, calculate the reduction of the impact force value in the coherent superposition group using a preset wave field attenuation formula, and vector superimpose the reduced stress components to generate a composite stress amplitude. The wave field attenuation formula is as follows: ； in, Represents the combined stress amplitude. Representing the The impact force value of each wave source, Representing the The straight-line distances corresponding to each wave source Represents the geometric diffusion factor. Represents the medium damping coefficient. This represents the total number of wave sources within a coherent superposition group; S43: Perform energy conversion on each wave source in the incoherent component, calculate the square term of its stress amplitude and perform scalar accumulation, and obtain the energy of the incoherent component by taking the square root of the accumulation result.
6. The method for assessing the health status of roadbed structures according to claim 5, characterized in that, The specific steps of S5 are as follows: S51: The combined stress amplitude and the incoherent component energy are weighted and combined to generate the background stress that reflects the background vibration intensity inside the subgrade, and the maximum equivalent dynamic stress is calculated by combining the static load stress of the subgrade. S52: Obtain the SN fatigue curve parameters of the roadbed material, calculate the upper limit of the allowable stress of the material under the current state based on the current loading frequency and service cycle, and set it as the fatigue limit; S53: Compare the maximum equivalent dynamic stress with the fatigue limit. If the former is greater than the latter, it is determined that the current volume element has a risk of structural failure, and its spatial geometric center coordinates are marked as the damage point. S54: Traverse all volumetric elements in the subgrade structure, assign high-risk label values to elements marked as damage points, assign low-risk label values to the remaining elements, construct a three-dimensional matrix, and form a risk distribution voxel map.
7. The method for assessing the health status of roadbed structures according to claim 6, characterized in that, The background stress calculation process of S51 includes: Obtain the coherent weighting factor and the incoherent weighting factor, multiply the combined stress amplitude by the coherent weighting factor to obtain the main wave field stress, and multiply the incoherent component energy by the incoherent weighting factor to obtain the scattered field stress. The background stress is generated by linearly superimposing the main wave field stress and the scattered field stress.
8. The method for assessing the health status of roadbed structures according to claim 7, characterized in that, The voxel map formation process of S54 includes: Establish a three-dimensional Cartesian coordinate system that is consistent with the physical dimensions of the roadbed, and map all volume units to the coordinate system according to their spatial geometric center coordinates; Based on the ratio of the maximum equivalent dynamic stress to the fatigue limit, a corresponding color level value or transparency parameter is assigned to each damage point, and a visualized risk distribution voxel map is generated.
9. The method for assessing the health status of roadbed structures according to claim 8, characterized in that, The process of determining the time step parameter in S12 includes: Acquire the data sampling frequency of the detection sensor and the cutoff frequency of the high-frequency vibration of the wheel; Based on the Nyquist sampling theorem, the minimum time interval that can completely reconstruct the characteristics of the wheel impact signal is calculated and set as the time step parameter.
10. A roadbed structure health status assessment system, characterized in that, The system is used to implement the roadbed structure health status assessment method according to any one of claims 1-9, the system comprising: The impact source discretization module is used to obtain the position and speed of the detected wheel. Based on the preset time step parameters, it generates three-dimensional coordinate points of the wheel load center through discretization processing. It associates the three-dimensional coordinate points with the value of the instantaneous impact force of the wheel on the ground to construct a set of discrete wave sources and transmits them to the wave path transmission analysis module. The path propagation analysis module is used to obtain the spatial geometric center coordinates of the volume unit, calculate the straight-line distance between the spatial geometric center coordinates and the three-dimensional coordinate points in the discrete wave source set, divide the straight-line distance by the propagation speed to obtain the propagation time value, and transmit it to the time difference comparison module. The time difference comparison module is used to obtain the generation time of the wave source and add it to the propagation time value to obtain the absolute time value. Based on the minimum value of the absolute time value, the difference is calculated, the difference is compared with the time threshold, and then transmitted to the wave field superposition processing module. The wave field superposition processing module is used to determine the coherent superposition group if the difference is less than the time threshold, subtract the impact force value in the coherent superposition group and add them to obtain the composite stress amplitude, and determine the incoherent component if the difference is greater than the time threshold, and accumulate the incoherent component energy, and then transmit the composite stress amplitude and the incoherent component energy to the structural fatigue diagnosis module. The structural fatigue diagnosis module is used to combine the synthetic stress amplitude with the background stress obtained by the incoherent component energy to obtain the maximum equivalent dynamic stress. If the maximum equivalent dynamic stress is greater than the fatigue limit, the spatial geometric center coordinates are marked as the damage point and a risk distribution voxel map is formed.