A stress distribution measurement method, system, device, and medium

Abstract

The application provides a stress distribution measurement method, system, device and medium, and belongs to the field of highway performance testing. The method comprises the following steps: obtaining a layered test piece simulating a pavement structure, the layered test piece comprising, from bottom to top, a fine sand layer, a gravel layer and an asphalt layer; repeatedly applying a load to the layered test piece to simulate the cyclic reciprocating action of a vehicle load, and collecting stress data and strain data of the sensor at preset time nodes; identifying contact points actually in contact with the gravel particles from all monitoring points according to the collected stress data and strain data; obtaining evaluation parameters based on the stress data and strain data of the contact points, determining the matching degree of the gravel layer and the asphalt layer in a point contact state according to the evaluation parameters, and providing adjustment suggestions. The application effectively prolongs the service life of the pavement and reduces maintenance costs.

Description

Technical Field

[0001] This invention relates to the field of highway performance testing, specifically to a stress distribution measurement method, system, equipment, and medium. Background Technology

[0002] With the global trend towards heavier loads and longer service life in highway transportation, large-diameter graded crushed stone is widely used as the core material for highway base or subbase courses due to its advantages such as high load-bearing capacity and good permeability. However, because the particle size of large-diameter crushed stone is usually between 20 and 60 mm and its shape is irregular, its contact with the overlying asphalt pavement is not a continuous surface contact in the traditional sense, but rather a discrete point contact pattern, with the area of ​​a single contact point typically less than 10 cm². 2 This unique contact characteristic, under the alternating effects of vehicle load and ambient temperature, can easily cause asphalt pavement to soften at high temperatures and be crushed by embedded stone particles, or crack at low temperatures due to stress concentration, ultimately resulting in ruts, subsidence, cracks and other defects, seriously affecting the stability and service life of the pavement structure.

[0003] To address the aforementioned issues, existing mechanical performance testing methods in the industry are primarily based on the assumption of continuous surface contact, employing traditional stress-strain testing techniques to evaluate the overall performance of pavement structures. Some advanced testing methods have introduced distributed sensing technology, capable of collecting raw stress-strain data across the entire pavement structure, attempting to guide material selection and structural design through macroscopic data analysis.

[0004] However, existing technologies still have significant shortcomings: on the one hand, test methods based on the assumption of continuous surface contact cannot accurately capture the unique local high stress and discrete distribution characteristics of point contact, resulting in a large deviation between test results and actual working conditions; on the other hand, although existing distributed stress detection methods can collect data across the entire area, they lack an effective distinction between actual stressed contact points and unstressed non-contact points. The resulting mixed data cannot truly reflect the actual stress state of the point contact interface, and it is even more difficult to establish a correlation between contact point data and the degree of damage and service limit state between the asphalt pavement and the crushed stone layer, thus failing to provide effective technical support for engineering decisions. Summary of the Invention

[0005] In view of this, it is necessary to provide a stress distribution measurement method, system, equipment and medium to solve the technical problem that the collected data in the existing technology cannot truly reflect the stress conditions of the highway and is difficult to provide effective decision-making.

[0006] To address the aforementioned technical problems, in a first aspect, the present invention provides a method for measuring stress distribution, comprising: A layered specimen simulating a road surface structure was obtained. The layered specimen consisted of a fine sand layer, a crushed stone layer, and an asphalt layer from bottom to top. The crushed stone particles in the crushed stone layer formed discrete point contacts with the lower surface of the asphalt layer. Sensors were distributed and embedded in a preset detection area on the lower surface of the asphalt layer. The sensors were used to collect stress and strain data. The layered specimen was repeatedly loaded to simulate the cyclic action of vehicle load, and stress and strain data from the sensor were collected at preset time points. Based on the collected stress and strain data, the contact points that actually come into contact with the crushed stone particles are identified from all monitoring points. Evaluation parameters are obtained based on the stress and strain data at the contact points. The degree of matching between the crushed stone layer and the asphalt layer in the point contact state is determined according to the evaluation parameters, and adjustment suggestions are provided.

[0007] In one possible implementation, obtaining the layered specimen simulating the road surface structure includes: An outer mold is provided, and the fine sand layer is formed at the bottom of the outer mold; The crushed stone particles are laid on the fine sand layer to form the crushed stone layer; An asphalt mixture is laid on top of the crushed stone layer, and the sensors are distributed and buried at the bottom of the asphalt mixture during the molding process. After compaction, the asphalt layer with the sensors embedded inside is formed.

[0008] In one possible implementation, identifying the contact points that actually contact the crushed stone particles from all monitoring points based on the collected stress and strain data includes: Obtain the peak stress at each monitoring point in the reference specimen, and set the peak stress as the contact determination threshold for the corresponding monitoring point. Based on the collected stress data, monitoring points with stress peak values ​​greater than or equal to the contact determination threshold and durations greater than or equal to a preset duration are selected as the contact points.

[0009] In one possible implementation, the evaluation parameters obtained based on the stress and strain data at the contact point include: Prepare at least two sets of test specimens with the same specifications as the layered specimen, and apply cyclic loads to them for different numbers of times. One set of test specimens with zero loads is used as the reference specimen. Obtain stress and strain data of the contact points identified in the reference specimen, take the stress peak value in the stress data as the reference stress peak value, and take the deformation amount corresponding to the strain data as the reference deformation amount. Based on the stress and strain data at the corresponding contact points in the test piece after applying a preset number of loads, the current peak stress and current deformation are obtained; the preset number of loads is a positive integer greater than 1. The degree of stress attenuation is determined based on the ratio of the difference between the reference stress peak and the current stress peak to the reference stress peak. The degree of deformation sensitivity is determined based on the ratio of the difference between the current deformation and the reference deformation to the preset number of times. The stress distribution characteristics are determined based on the spatial location of the contact point on the lower surface of the asphalt layer and its corresponding stress value. The evaluation parameters are obtained based on the stress attenuation degree, the deformation sensitivity, and the stress distribution characteristics.

[0010] In one possible implementation, determining the degree of matching between the crushed stone layer and the asphalt layer in a point-contact state based on the evaluation parameters and providing adjustment suggestions includes: Based on the numerical ranges of the stress attenuation degree and the deformation sensitivity, and combined with the stress distribution characteristics of the contact points, multiple evaluation levels are obtained to describe the degree of matching. Based on the evaluation level, corresponding adjustment recommendations are determined, including at least one of material selection, structural layer thickness adjustment, and compaction degree.

[0011] In one possible implementation, the repeated application of loads to the layered specimen includes... The layered specimen is placed inside the rutting apparatus, and a hardboard is placed on top of the layered specimen to distribute the wheel load of the rutting apparatus. The key parameters of the rutting instrument are set, including the wheel movement speed, wheel pressure value, ambient temperature and test duration. The rutting instrument, with the key parameters set, is started, and the wheel of the rutting instrument moves cyclically along a preset path. The set movement trajectory is a complete cycle, simulating the cyclical action of vehicle load.

[0012] One possible implementation also includes: During repeated loading, the deformation depth of the asphalt layer is determined based on the collected strain data; The deformation ratio is obtained by calculating the ratio of the deformation depth to the asphalt layer thickness; When the deformation ratio reaches a preset deformation threshold, the corresponding number of load repetitions is recorded as the fatigue life of the asphalt layer to characterize the asphalt layer's resistance to damage.

[0013] Secondly, the present invention also provides a stress distribution measurement system, comprising: The acquisition module is used to acquire a layered specimen simulating a road surface structure. The layered specimen consists of a fine sand layer, a crushed stone layer, and an asphalt layer from bottom to top. The crushed stone particles in the crushed stone layer form discrete point contacts with the lower surface of the asphalt layer. Sensors are distributed and embedded in a preset detection area on the lower surface of the asphalt layer. The sensors are used to collect stress data and strain data. The test acquisition module is used to repeatedly apply loads to the layered specimen to simulate the cyclic action of vehicle loads, and to acquire stress and strain data from the sensors at preset time points. The identification and recording module is used to identify the contact points that actually come into contact with the crushed stone particles from all monitoring points based on the collected stress and strain data. The processing module is used to obtain evaluation parameters based on the stress and strain data of the contact points, determine the degree of matching between the crushed stone layer and the asphalt layer in the point contact state according to the evaluation parameters, and provide adjustment suggestions.

[0014] Thirdly, the present invention also provides an electronic device, including a memory and a processor, wherein, The memory is used to store programs; The processor, coupled to the memory, is used to execute the program stored in the memory to implement the steps in the stress distribution measurement method described in any of the above implementations.

[0015] Fourthly, the present invention also provides a computer-readable storage medium for storing a computer-readable program or instructions, which, when executed by a processor, can implement the steps of the stress distribution measurement method described in any of the above implementations.

[0016] The beneficial effects of this invention are as follows: The stress distribution measurement method provided by this invention first forms a discrete point-like contact pattern inside the specimen, and combines this with high-density distributed sensors embedded in the contact interface. This allows for accurate capture of the local high-stress distribution characteristics of the point-like contact area, achieving realistic simulation and accurate measurement of point-like contact conditions. Furthermore, this invention accurately selects contact points from massive monitoring data by setting dual judgment criteria of stress threshold and duration, eliminating evaluation bias caused by mixed data across the entire domain, and ensuring that all data sources for damage analysis are authentic and valid. This provides a basis for material selection and structural design in highway engineering, significantly reducing pavement maintenance costs and extending service life, demonstrating significant economic benefits and promotional value. This invention simulates point-contact scenarios through indoor experiments, incorporates a contact point identification mechanism, screens actual stressed contact points, and constructs quantitative evaluation parameters based on stress-strain data of the contact points. This objectively reflects the damage evolution law and mechanical matching degree of the point-contact interface, and measures the stress-strain distribution and dynamic changes under different loads and temperatures. It provides a scientific basis for material selection, structural design, and construction optimization of highway pavements, thereby significantly extending the service life of the pavement, reducing the frequency and investment of later maintenance, and ultimately effectively reducing the maintenance cost of the entire life cycle of the project. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic flowchart of an embodiment of the stress distribution measurement method provided by the present invention; Figure 2 This is a schematic diagram of sensor installation in the stress distribution measurement method provided by the present invention; Figure 3 This is a schematic diagram of the layered specimen structure provided by the present invention; Figure 4 A schematic diagram of the cyclic loading test apparatus provided by the present invention; Figure 5 This is a schematic diagram of the cyclic movement path of the wheel of the wheel rutting instrument provided by the present invention; Figure 6 This is a schematic diagram of the monitoring point layout provided by the present invention; Figure 7 This is a schematic diagram of the stress acquisition results provided by the present invention; Figure 8 This is a schematic diagram of the distribution of point contact points provided by the present invention; Figure 9A schematic diagram of an embodiment of the stress distribution measurement system provided by the present invention; Figure 10 A schematic diagram of an embodiment of the electronic device provided by the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] In the description of the embodiments of the present invention, unless otherwise stated, "multiple" means two or more. "And / or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0021] The terms "first," "second," etc., used in the embodiments of this invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a technical feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0022] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0023] This invention provides a method, system, device, and medium for measuring stress distribution, which are described below.

[0024] Figure 1 This is a schematic flowchart of an embodiment of the stress distribution measurement method provided by the present invention, as shown below. Figure 1 As shown, the stress distribution measurement methods include: S101. Obtain a layered specimen simulating a road surface structure. The layered specimen consists of a fine sand layer, a crushed stone layer, and an asphalt layer from bottom to top. The crushed stone particles in the crushed stone layer form discrete point contacts with the lower surface of the asphalt layer. Sensors are distributed and embedded in a preset detection area on the lower surface of the asphalt layer. The sensors are used to collect stress data and strain data.

[0025] It should be noted that the prepared layered specimens accurately reflect the stress characteristics of actual road structures. From bottom to top, the layered specimens consist of a fine sand layer, a large-diameter graded crushed stone layer, and an asphalt layer. The fine sand layer, constructed with fine sand of a gradation no greater than 4.75 mm, simulates the surface layer of a highway subgrade, providing a stable load-bearing foundation for the superstructure. The large-diameter graded crushed stone layer, through strict gradation design, ensures that the particle size is mainly distributed between 20 mm and 60 mm, guaranteeing a discrete point-like contact pattern with the lower surface of the asphalt layer, with each contact point having an area no greater than 10 cm². 2 To simulate the actual contact between the crushed stone base course and the asphalt layer in real engineering projects, high-density sensors are distributed and embedded within a pre-set detection area on the lower surface of the asphalt layer during the asphalt layer forming process. The sensor density is no less than 10 cm. 2 One is used for real-time acquisition of stress and strain data. This lower surface is the interface that will subsequently make point-like contact with the gravel layer.

[0026] S102. Repeatedly apply loads to the layered specimen to simulate the cyclic action of vehicle loads, and collect stress and strain data from the sensors at preset time points.

[0027] It should be noted that: the prepared layered specimen is placed in the rutting apparatus, and the load on the apparatus wheels is distributed by placing hardwood boards to avoid stress concentration and damage to the specimen. The rutting apparatus, with the key parameters set, is started, and the apparatus wheels move cyclically along a preset path to simulate the cyclic action of actual vehicle loads. At preset time points (such as the 15th minute, 45th minute, and 75th minute of the test), stress and strain data from all embedded sensors are collected, and the mechanical response of the specimen at different loading stages is recorded.

[0028] S103. Based on the collected stress and strain data, identify the contact points that actually come into contact with the crushed stone particles from all monitoring points.

[0029] It should be noted that, based on the collected stress data, contact points that actually come into contact with the gravel particles are selected from the monitoring points across the entire area.

[0030] S104. Based on the stress and strain data of the contact points, evaluation parameters are obtained. The degree of matching between the crushed stone layer and the asphalt layer in the point contact state is determined according to the evaluation parameters, and adjustment suggestions are provided.

[0031] It should be noted that, based on the stress and strain data of the identified contact points, multiple evaluation parameters are calculated to assess the point contact condition. These parameters are used as the basis for evaluation to comprehensively assess the mechanical compatibility between the crushed stone layer and the asphalt layer under point contact conditions. Corresponding engineering adjustment measures are provided as adjustment suggestions based on the evaluation results.

[0032] In summary, the stress distribution measurement method provided by this invention first forms a discrete point-like contact pattern inside the specimen, and then combines this with high-density distributed sensors embedded in the contact interface. This allows for accurate capture of the local high-stress distribution characteristics of the point-like contact area, achieving realistic simulation and precise measurement of point-like contact conditions. Furthermore, this invention accurately selects contact points from massive monitoring data by setting dual criteria of stress threshold and duration, eliminating evaluation bias caused by mixed data across the entire domain and ensuring that all data sources for damage analysis are authentic and valid. This provides a basis for material selection and structural design in highway engineering, significantly reducing pavement maintenance costs and extending service life, demonstrating significant economic benefits and promotional value. This invention simulates point-contact scenarios through indoor experiments, incorporates a contact point identification mechanism, screens actual stressed contact points, and constructs quantitative evaluation parameters based on stress-strain data of the contact points. This objectively reflects the damage evolution law and mechanical matching degree of the point-contact interface, and measures the stress-strain distribution and dynamic changes under different loads and temperatures. It provides a scientific basis for material selection, structural design, and construction optimization of highway pavements, thereby significantly extending the service life of the pavement, reducing the frequency and investment of later maintenance, and ultimately effectively reducing the maintenance cost of the entire life cycle of the project.

[0033] In some embodiments of the present invention, step S101 includes: S201. Provide an outer mold, and form the fine sand layer at the bottom of the outer mold.

[0034] It should be noted that a rigid outer mold capable of withstanding the lateral pressure of the internal structural layers during loading is provided to ensure the layered specimen maintains morphological stability during molding and testing, preventing damage to the point-contact morphology due to lateral displacement. The outer mold is made of steel. A suitable outer mold for the specimen should be selected. Figure 2 As shown, the internal dimensions are A layer with a thickness of [thickness missing] is laid at the bottom of the outer mold. The fine sand layer, with particle size controlled below 4.75mm, ensures its density and uniformity. The fine sand layer simulates the surface layer of the roadbed in actual highway engineering structures, ensuring the stress stability of the base layer.

[0035] S202, The crushed stone particles are laid on the fine sand layer to form the crushed stone layer.

[0036] It should be noted that: A large-diameter graded crushed stone layer is laid on top of the fine sand layer. Following the requirements for large-diameter gradation in the "Technical Specifications for Construction of Highway Pavement Base Course" (JTG / TF20-2015), the large-diameter graded crushed stone undergoes gradation design (in the field of road engineering, this refers to the process of designing the proportion of different particle sizes of stone; its essence is to achieve the densest and most stable state of the mixture by rationally combining crushed stone particles of different sizes). This crushed stone layer serves as the intermediate layer of the layered specimen, and its thickness is [not specified]. Strict gradation control ensures that the particle size of the crushed stone is mainly distributed between 20mm and 60mm. This particle size range ensures a discrete point-like contact pattern between the crushed stone layer and the subsequent asphalt layer (the area of ​​a single contact point ≤ 10cm²). 2 This is to simulate the actual contact state between the crushed stone base course and the asphalt layer in actual engineering projects.

[0037] Studies have shown that the mechanical properties of large-diameter crushed stone mixtures mainly depend on the skeletal contact state between aggregate particles. The distribution and morphology of contact points between particles directly affect the load-bearing capacity and deformation characteristics of the mixture. During crushed stone paving, uniform gradation should be ensured to avoid segregation of coarse and fine particles and ensure the formation of a stable skeletal structure in the crushed stone layer. After paving, appropriate compaction should be carried out to initially form an interlocking state between the crushed stone particles, providing a stable contact interface for the subsequent asphalt layer formation.

[0038] S203. Lay asphalt mixture on the crushed stone layer, and during the molding process, distribute and embed the sensors to the bottom of the asphalt mixture. After rolling and molding, the asphalt layer with the sensors embedded inside is formed.

[0039] It should be noted that asphalt mixture is laid on top of the crushed stone layer. In this embodiment, SBS modified asphalt is used, and the aggregate gradation is designed according to the requirements of hot-mix dense gradation AC-25 asphalt concrete in the "Technical Specification for Construction of Highway Asphalt Pavement" (JTG F40-2004). After the asphalt mixture is laid and before compaction begins, optical grating sensors are distributed and embedded in a pre-set detection area at the bottom of the asphalt mixture (i.e., the interface side in contact with the crushed stone layer). The number of sensors can be adjusted according to the acquisition accuracy. The sensor density is not less than one sensor per 10 cm² to ensure that the local stress-strain characteristics of the point contact area can be captured. In this embodiment, multiple sensors are deployed in a pre-set 3×3 grid area on the lower surface of the asphalt layer, such as... Figure 3As shown, grating sensors 1-4 are embedded in the lower surface of asphalt layer 5. The embedding positions of the sensors should be accurately marked so that the monitoring points can be correlated with spatial coordinates during subsequent data analysis. After the sensors are embedded, a multi-purpose box roller compactor (RBC) (patent number: 202110386177.X) is used for compaction. During the compaction process, the asphalt mixture gradually densifies, and the sensors are fixed inside the asphalt layer, ultimately forming an asphalt layer with sensors embedded inside. The thickness of the formed asphalt layer is 50mm, and its size matches the mold. At this time, the sensor embedding position is located in the preset detection area on the lower surface of the asphalt layer, which is the interface for subsequent point contact with the crushed stone layer. The layered specimen prepared by the above steps consists of a fine sand layer, a large-particle-size graded crushed stone layer, and an asphalt layer with sensors embedded inside, from bottom to top. It completely simulates the layered composition and contact characteristics of the actual pavement structure, providing a reliable test object for subsequent point contact stress distribution measurement tests.

[0040] In this embodiment, the fine sand layer simulates the roadbed surface layer, the crushed stone layer simulates the base layer, and the asphalt layer simulates the surface layer. This three-layer structure realistically simulates the layered composition of an actual highway pavement, enabling the indoor test results to more accurately reflect the actual engineering situation. Furthermore, by distributively embedding sensors at the bottom (i.e., the contact interface side) of the asphalt layer during its forming process, the sensors can directly sense the local stress and strain response of the point contact area, avoiding signal attenuation and positional deviation that may be caused by external patch measurements, thus improving the accuracy of contact point identification.

[0041] In some embodiments of the present invention, step 103 includes: S301. Obtain the stress peak value at each monitoring point in the reference specimen, and set the stress peak value as the contact judgment threshold for the corresponding monitoring point.

[0042] It should be noted that: First, a reference specimen with specifications completely identical to the test specimen was prepared. From bottom to top, the reference specimen consisted of a fine sand layer, a crushed stone layer, and an asphalt layer, with sensors also distributed and embedded on the lower surface of the asphalt layer. No cyclic loading was applied to the reference specimen, i.e., the number of loading cycles was zero, to obtain the background stress characteristics at each monitoring point in the initial state. The reference specimen was placed statically in the test environment, and stress data at each monitoring point was collected under no-load conditions. Since there was no external load acting on the specimen, the stress values ​​collected at each monitoring point mainly came from the material's own weight, residual stress, and environmental disturbances. The peak stress at each monitoring point under no-load conditions was obtained, and this peak stress was set as the contact threshold for that monitoring point.

[0043] S302. Based on the collected stress data, the monitoring points with stress peak values ​​greater than or equal to the contact determination threshold and durations greater than or equal to the preset duration are selected as the contact points.

[0044] It should be noted that for each monitoring point, the stress value change is continuously monitored. When the stress peak value at a point reaches or exceeds its corresponding contact determination threshold, it is preliminarily determined that the point may be in contact. However, instantaneous stress fluctuations may be caused by noise interference or accidental factors, which are insufficient to prove a stable contact state. Therefore, a duration determination condition is further introduced: only when the stress value reaches or exceeds the contact determination threshold for a preset duration (0.5 seconds in this embodiment) can it be confirmed that the point has formed a stable contact with the gravel particles.

[0045] Monitoring points that meet both of the above conditions (peak stress ≥ contact threshold and duration ≥ preset duration) are identified as contact points. The stress and strain data collected from these points will serve as the basis for subsequent analysis, used to calculate evaluation parameters and mechanical fit. Monitoring points whose peak stress is consistently below the contact threshold, or whose peak stress occasionally exceeds the contact threshold but the duration is less than the preset duration, are identified as non-contact points. Data from these non-contact points are not included in subsequent contact stress characteristic analysis, thus effectively eliminating background noise interference from non-contact areas.

[0046] In this embodiment, by setting a contact determination threshold (based on the background stress at each point on the reference specimen) and a duration-based dual determination criterion, the contact points that actually come into contact with the gravel particles are accurately screened from massive monitoring data, ensuring that all data sources for subsequent analysis are authentic and valid. Furthermore, by accurately identifying the contact points, precise input is provided for obtaining subsequent evaluation parameters, ensuring the accuracy and reliability of the matching degree calculation.

[0047] In some embodiments of the present invention, the evaluation parameters obtained based on the stress and strain data at the contact points include: S401. Prepare at least two sets of test specimens with the same specifications as the layered specimen, and apply cyclic loads to them for different numbers of times. One set of test specimens with zero loads is used as the reference specimen. S402. Obtain stress data and strain data of the contact points identified in the reference specimen, and take the stress peak value in the stress data as the reference stress peak value and the deformation amount corresponding to the strain data as the reference deformation amount. S403. Based on the stress and strain data of the corresponding contact points in the test piece after applying a preset number of loads, obtain the current stress peak and the current deformation; the preset number of loads is a positive integer greater than 1.

[0048] It should be noted that at least two sets of test specimens with specifications completely identical to the aforementioned layered specimens were prepared. The material composition, structural dimensions, and sensor layout of all test specimens were kept identical to ensure comparability of test results. Different numbers of cyclic loads were applied to the test specimens to simulate the damage accumulation process of the pavement structure at different service stages. One set of test specimens was subjected to zero load cycles, serving as a baseline specimen. This baseline specimen did not undergo any cyclic loading and was used to obtain the mechanical response characteristics of the point contact interface in an initially undamaged state. The remaining test specimens were subjected to a predetermined number of cyclic loads, where the predetermined number was a positive integer greater than 1. The loading conditions for all test specimens were kept consistent to ensure that differences in damage levels stemmed solely from variations in the number of load cycles.

[0049] For the reference specimen, based on the contact points identified in step S103, stress and strain data for each contact point are extracted. The peak stress at each contact point is used as the reference peak stress. The deformation corresponding to the strain data is used as the reference deformation. Peak reference stress This reflects the initial load-bearing capacity of the contact point under undamaged conditions, and the reference deformation. It reflects the initial geometry of the contact point.

[0050] For the test specimen subjected to a preset number of cyclic loads, stress and strain data are extracted from the corresponding contact points based on the same contact point number. The peak stress after loading is taken as the current peak stress. The deformation after loading is taken as the current deformation. Current peak stress This reflects the remaining load-bearing capacity of the contact points of the test piece after a certain number of loading cycles, and the current deformation. It reflects the cumulative deformation of the contact points of the test piece under load.

[0051] S404. Determine the degree of stress attenuation based on the ratio of the difference between the reference stress peak and the current stress peak to the reference stress peak.

[0052] It should be noted that stress attenuation is used to characterize the degree to which the load-bearing capacity of the material at the contact point degrades with increasing load cycles. The stress attenuation is calculated using the following formula. Degree of stress attenuation This reflects the cumulative fatigue damage of the material under cyclic loading. Stress attenuation degree. The larger the value, the more severe the loss of load-bearing capacity at the contact point and the higher the degree of material deterioration.

[0053] S405. Determine the deformation sensitivity based on the ratio of the difference between the current deformation and the reference deformation to the preset number of times.

[0054] It should be noted that deformation sensitivity is used to characterize the rate of deformation development at the contact point under load. The deformation sensitivity is calculated using the following formula. Deformation sensitivity This reflects the strength of the material's deformation response to load after the accumulation of damage. Deformation sensitivity. The larger the value, the easier it is for the material to accumulate deformation under the same load conditions, and the worse its resistance to deformation.

[0055] S406. Determine the stress distribution characteristics based on the spatial location of the contact point on the lower surface of the asphalt layer and its corresponding stress value; S407. The evaluation parameters are obtained based on the stress attenuation degree, the deformation sensitivity degree, and the stress distribution characteristics.

[0056] It should be noted that stress distribution characteristics are used to characterize the spatial distribution of contact points on the lower surface of the asphalt layer and the corresponding stress value distribution. Based on the spatial coordinates of each contact point (e.g., determined by the grid position during sensor deployment) and its corresponding stress peak value, a stress distribution cloud map or a three-dimensional stress distribution map is drawn. Stress distribution characteristics include the distribution density of contact points, the spatial variability of stress peak values, and the concentration location of high-stress areas. The stress attenuation degree, deformation sensitivity, and stress distribution characteristics are used together as evaluation parameters to comprehensively assess the mechanical behavior of the crushed stone layer and the asphalt layer under point contact conditions.

[0057] In this embodiment, by introducing three evaluation parameters—stress attenuation degree, deformation sensitivity, and stress distribution characteristics—the original stress and strain data are transformed into evaluation parameters with clear physical meaning, enabling the mechanical behavior of the point contact interface to be objectively quantified and compared. Furthermore, by setting a benchmark specimen with zero loading cycles, the benchmark stress peak and benchmark deformation at each contact point in the initial undamaged state are obtained. This provides a scientific reference standard for the subsequent quantification of damage degree, eliminating the influence of individual specimen differences and material background characteristics on the evaluation results, and improving the accuracy and reliability of the evaluation.

[0058] In some embodiments of the present invention, determining the degree of matching between the crushed stone layer and the asphalt layer in a point-contact state based on the evaluation parameters and providing adjustment suggestions includes: S501. Based on the numerical range of the stress attenuation degree and the deformation sensitivity, and combined with the stress distribution characteristics of the contact point, multiple evaluation levels are obtained to describe the degree of matching. S502. Determine corresponding adjustment suggestions based on the evaluation level. The adjustment suggestions include at least one of material selection, structural layer thickness adjustment, and compaction degree.

[0059] It should be noted that, based on statistical analysis of extensive experimental data and long-term tracking of pavement service performance, this invention establishes an evaluation standard for the mechanical matching degree between the crushed stone layer and the asphalt layer under point contact conditions. The evaluation levels are mainly determined based on the degree of stress attenuation, deformation sensitivity, and stress distribution characteristics, resulting in at least two evaluation levels describing the matching degree. There can be two, three, four, or even five evaluation levels, depending on the requirements. Based on the above evaluation level division, corresponding engineering adjustment measures are set as adjustment suggestions for different levels to achieve optimized design of the point contact interface. The adjustment suggestions include at least one of the following: material selection, structural layer thickness adjustment, and compaction degree.

[0060] In this embodiment, an evaluation standard system is constructed by organically combining three quantitative evaluation parameters: stress attenuation degree, deformation sensitivity, and stress distribution characteristics. This allows for the objective and accurate assessment of the mechanical matching degree of the point contact interface, providing a clear basis for engineering decision-making. Furthermore, by matching specific optimization suggestions (such as compaction optimization, thickness adjustment, and material upgrades) to different evaluation levels, the transformation of experimental data into engineering guidance is achieved. Moreover, through the classification of evaluation levels, this invention can not only evaluate existing designs but also provide early warnings of potential damage risks. When test results approach the level boundary value, designers are prompted to pay attention to the long-term performance evolution trend of the contact interface, allowing for preventative measures to be taken before damage occurs, thereby avoiding early damage and extending the service life of the pavement. Furthermore, the evaluation system and adjustment suggestions provided by this invention offer clear performance targets and verification methods for the development of new asphalt pavement structures and materials. Researchers can develop new materials and structural forms adapted to point contact conditions based on different evaluation standards, and verify and optimize them through the experimental methods of this invention, thereby promoting technological progress in the highway engineering industry.

[0061] In some embodiments of the present invention, the repeated application of load to the layered specimen includes: S601. Place the layered specimen inside the rutting apparatus and erect a hardboard above the layered specimen. The hardboard is used to distribute the wheel load of the rutting apparatus.

[0062] It should be noted that the layered specimen prepared according to step S101 is placed inside the rutting apparatus. A hardboard is placed on top of the specimen, the size of which is slightly smaller than the inner diameter of the outer mold. The purpose of the hardboard is to distribute the load of the rutting apparatus wheel, avoid damage to the specimen surface due to local stress concentration, and ensure that the load can be evenly transferred to the lower structural layer to simulate the contact state between the tire and the road surface in actual road conditions.

[0063] S602. Set the key parameters of the rutting instrument, wherein the key parameters, the rutting instrument parameters include the rutting instrument wheel rotation speed, wheel pressure value, ambient temperature and test duration; S602. Start the rutting instrument with the key parameters set, and make the wheel of the rutting instrument move cyclically along the preset path. The set movement trajectory is a complete cycle, simulating the cyclic action of vehicle load.

[0064] It should be noted that, according to the experimental design requirements, the key parameters of the rutting device were set. Then, the rutting device, with its key parameters set, was started. The rutting device uses a crank-connecting rod drive mechanism to make the test wheel reciprocate along the surface of the specimen. That is, a complete cycle of "ABCBA" simulates the actual vehicle load mode: the rutting device wheel rolls from the initial position A to the middle position B, then continues rolling to position C, and then returns to positions B and A. This round-trip path completely simulates the entire process of the rutting device wheel entering, running over, and leaving the specimen. During the experiment, the rutting device wheel continuously reciprocates at a set rate, applying a cyclic load to the specimen.

[0065] In this embodiment, by precisely setting key parameters such as the wheel movement speed, wheel pressure, and ambient temperature, the road service environment under different traffic loads and climatic conditions can be simulated, realistically simulating the cyclic action of vehicle loads. Furthermore, by setting up hardwood boards to distribute the wheel load, contact morphology damage caused by local stress concentration is avoided, ensuring the stability of the point contact interface and the reliability of the test data during the test.

[0066] In some embodiments of the present invention, it further includes: S701. During repeated application of load, the deformation depth of the asphalt layer is determined based on the collected strain data. S702. Calculate the ratio of the deformation depth to the asphalt layer thickness to obtain the deformation ratio; S703. When the deformation ratio reaches the preset deformation threshold, the corresponding number of load repetitions is recorded as the fatigue life of the asphalt layer to characterize the anti-damage performance of the asphalt layer.

[0067] It should be noted that during the cyclic loading test, distributed grating sensors continuously collect strain data at each contact point on the lower surface of the asphalt layer. The strain data reflects the degree of local deformation at the contact point under load. By integrating the strain data, the vertical deformation at each monitoring point can be obtained. During the test, the system records the deformation depth in real time after each loading cycle. The deformation depth of the asphalt pavement is calculated during the cyclic loading process. With asphalt pavement thickness ratio This ratio is taken as the deformation ratio. The magnitude of the deformation ratio directly reflects the degree of damage to the asphalt layer under point contact load: the smaller the deformation ratio, the stronger the asphalt layer's resistance to deformation and the better its structural integrity is maintained; the larger the deformation ratio, the more severe the accumulated damage and the closer it is to the failure state. Based on pavement engineering design experience and relevant specifications, a preset deformation threshold is set according to the actual engineering requirements for asphalt layer deformation control. The preset deformation threshold represents the maximum allowable deformation of the asphalt layer under point contact conditions. Exceeding this threshold indicates that the structure has entered the fatigue failure stage and cannot continue normal service. During the loading process, the system continuously compares the real-time deformation ratio. With preset threshold The magnitude relationship. When the deformation ratio x i First time reaching or exceeding At each load cycle, the corresponding number of load repetitions, N_b, is recorded. This number of repetitions, N_b, is defined as the fatigue life of the asphalt layer under the test conditions. Fatigue life is a core quantitative indicator for evaluating the anti-damage performance of asphalt layers. This indicator comprehensively reflects the influence of various factors such as material properties, structural thickness, and contact morphology on the durability of the asphalt layer. A longer fatigue life indicates that the asphalt layer can maintain structural integrity under a greater number of cyclic loads, exhibiting excellent fatigue resistance and suitability for heavy-load traffic sections. Conversely, a shorter fatigue life indicates that the asphalt layer undergoes significant deformation after only a few load cycles, demonstrating insufficient fatigue resistance and requiring optimization measures such as adjusting the material mix, increasing the structural layer thickness, or replacing it with high-modulus modified asphalt. By comparing the fatigue lives of different materials, thicknesses, and gradations of crushed stone, direct experimental evidence can be provided for the optimized design of pavement structures.

[0068] In this embodiment, the ratio of asphalt layer deformation depth to thickness is used as the criterion for fatigue failure, directly linking fatigue life evaluation with observable road surface defects such as rutting and subsidence, making the test results closer to actual engineering needs. Furthermore, this invention conducts fatigue life testing under point contact conditions, making fatigue performance evaluation more closely reflect the actual stress state of large-diameter crushed stone base pavement.

[0069] For example, the present invention provides a method for measuring the point contact stress distribution between large-particle-size graded crushed stone and asphalt pavement, comprising the following steps: S1. Select a suitable external mold for the specimen, such as... Figure 2 As shown, the inner dimensions of the outer mold are =400 400 240mm.

[0070] S2, Laying on the bottom of the outer mold =20mm thick fine sand layer with a gradation not exceeding 4.75mm.

[0071] S3, Laying The large-particle-size graded crushed stone layer with a diameter of 230mm is designed according to the large-particle-size gradation in the specification "Technical Details for Construction of Highway Pavement Base Course" (JTG / T F20-2015) to ensure that it forms discrete point-like contact with the asphalt layer (the area of ​​a single contact point ≤ 10cm²). 2 ).

[0072] S4. Select materials and design mix proportions for the asphalt mixture, with an asphalt layer thickness of [missing information]. In this embodiment, the aggregate gradation of the asphalt mixture is based on the hot-mix dense gradation AC-25 asphalt concrete in the "Technical Specification for Construction of Highway Asphalt Pavement" (JTG F40-2004). SBS modified asphalt is selected as the asphalt binder, and the asphalt layer size is 400 mm. 400 50mm, formed using a multi-purpose box-type roller forming machine (RBC) (patent number: 202110386177.X), and with distributed grating sensors 1, 2, 3 and 4 embedded on the upper and lower surfaces (e.g. Figure 3 As shown in the figure, the asphalt layer 5 is made by placing it into the outer mold, and then the layered specimen is prepared.

[0073] S5. Prepare three sets of test specimens with the same specifications as the above-mentioned specimens, and number them as specimen SJ1, specimen SJ2, and specimen SJ3, respectively. Specimen SJ1 will be subjected to 0 cycles of loading and will serve as the reference specimen; specimen SJ2 will be subjected to 3000 cycles of loading; and specimen SJ3 will be subjected to 6000 cycles of loading. Place the test specimens inside the rutting apparatus, and erect a test structure with dimensions of [missing information]. =370 370 20mm thick hardwood board. (Example) Figure 4As shown, 31 is the wheel of the rutting meter, 32 is the hardwood board, 33 is the asphalt layer, 34 is the gravel layer, 35 is the fine sand layer, and 36 is the outer mold. Design a cyclic loading scheme and set the key parameters of the rutting meter: set the running distance of the rutting meter wheel 31. Adjust the rotation speed of the rut gauge wheel 31 to correspond to the size of the scale plate. wheel pressure and the temperature inside the rutting instrument box Set the test time and stress acquisition time nodes , , For example, the running distance of the rut meter wheel 31 is set to 400 mm, the rotation speed of the rut meter wheel 31 is adjusted to 42 r / min, the wheel pressure value is selected as 0.7 MPa, the ambient temperature inside the rut meter chamber is set to 40℃, the test duration is set to 1.5 h, and stress acquisition time nodes are also specified. , , They were in the 15th minute, the 45th minute, and the 75th minute, respectively.

[0074] The data for each group of specimens are shown in Table 1:

[0075] Table 1. Test data for each group of specimens S6. Start the rutting instrument. The test process is illustrated in the diagram: the wheel 31 of the rutting instrument moves cyclically along the steel rail on the upper surface of the layered specimen, as shown below. Figure 5 As shown, the rut gauge wheel 31 rolls from the initial position A to the intermediate position B, then to position C, and returns to position B and then to position A. Each complete cycle of "ABCBA" is counted as one loading operation. The number of loading operations completed within the loading time t is recorded as follows: The test simulates the cyclic loading of a real high-speed vehicle. The wheel 31 moves cyclically on the rail and applies load to the lower structure of the specimen, collecting stress and strain data at sampling points on the upper and lower surfaces of the asphalt layer.

[0076] S7. During the loading process, stress and strain data at all monitoring points across the entire area are collected using distributed grating sensors. For example... Figure 6 As shown, 9 sampling points (3×3) were selected on the lower surface of the asphalt layer. Figure 6 (a) 61~69), select the center point on the upper surface of the asphalt layer ( Figure 6 (b) Data collection is performed in section 616. Figure 6 (a) and Figure 6 In (b), 611, 612, 613, and 614 are distributed grating sensors, 610 is the lower surface of the asphalt layer, 615 is the upper surface of the asphalt layer, and 616 is the sampling point on the upper surface. Extract the stress values ​​at the center point of the lower surface of the wheel when it is located at positions A, B, and C within a set time period, and plot the load position-stress peak-time relationship graph. Collect data at the preset time points of 15 minutes, 45 minutes, and 75 minutes of the test. Figure 6 The wheel of the wheel tracker was located at different positions in a certain cycle near the sampling point shown. Figure 5 When the data points are at positions A, B, and C, the stress data collected at each point within one cycle at this time node are selected. The relationship between the image of the wheel 31 position change in this cycle and the stress acquisition situation of the upper and lower surface acquisition points is shown in the figure below. Figure 7 As shown in (a), (b), (c) and (d).

[0077] S8. Identify contact points: Based on the stress value of the reference specimen, set contact judgment thresholds for each contact point. ,in This represents the peak stress at that point in the reference specimen. During the cyclic loading process at the data acquisition time points, specimens with peak stresses greater than or equal to [a certain value] are selected. Monitoring points with a stress duration greater than or equal to 0.5 s are identified as contact points; stress peak values ​​less than... The monitoring point was determined to be a non-contact point. Contact determination was performed on sampling point 15. The contact determination threshold for this point was... During the loading process, the peak stress was 0.42 MPa and the stress duration was greater than 0.5 seconds, so sampling point 15 was determined to be the contact point.

[0078] S9. Based on the test specimen data, construct a quantitative index for point contact damage. Stress attenuation degree. (Formula 1) reflects the degree of degradation of the load-bearing capacity of the material in the contact area, where, The reference stress peak value, Current peak stress; Deformation sensitivity Formula 2 reflects the deformation response intensity of the material to the load after damage accumulation, where This represents the current deformation. As the reference deformation amount, The number of cycles is used. The peak stress at the identified contact point is obtained from the reference specimen (specimen SJ1) as the reference peak stress σ. 0(max) (Center point σ) 0(max) =0.62MPa), and the deformation corresponding to the strain data is used as the reference deformation S0 (center point S0=0.02mm). The current peak stress σ at the corresponding contact point is obtained from specimen SJ2 (3000 cycles) and specimen SJ3 (6000 cycles). i and current deformation Center point of specimen SJ2 =0.51MPa, =0.07mm; Center point of specimen SJ3 =0.45MPa, =0.15mm. Based on formulas (1) and (2), the stress attenuation and deformation sensitivity of the test piece SJ2 are calculated to be 0.177 and... The stress attenuation and deformation sensitivity of the test specimen SJ3 were calculated to be 0.274 and... : ; ; ; ; S10. Combining damage indicators and stress distribution characteristics, an evaluation standard for the point matching degree of large-diameter crushed stone-asphalt pavement was formulated, as shown in Table 2. Based on Table 2, the point matching degree of large-diameter crushed stone-asphalt pavement was determined. Group 2 corresponds to Level II, which is suitable for medium-heavy traffic and requires optimization of compaction technology; Group 3 corresponds to Level III, which is relatively suitable for medium-heavy traffic and requires appropriate increase in asphalt pavement thickness.

[0079]

[0080] Table 2. Evaluation Criteria for the Point Matching Degree of Large-Diameter Crushed Stone-Asphalt Pavement According to the evaluation criteria in Table 2, the stress attenuation of specimen SJ2 (3000 cycles) was 17.7%, and the deformation sensitivity was 1.67 × 10⁻⁶. -5 / time, corresponding to Level II matching degree, it is recommended to optimize the asphalt mixture compaction degree; the stress attenuation degree of specimen SJ3 (6000 times) is 27.4%, and the deformation sensitivity is 2.17×10 -5 For each instance, corresponding to a matching grade of III, it is recommended to increase the asphalt layer thickness by 5-10mm.

[0081] S11. Evaluate the fatigue life of the asphalt layer: Test the deformation depth of the asphalt pavement. With asphalt pavement thickness ratio After the test, the relationship curve between the strain at the center point of the lower surface of the asphalt layer (denoted as the asphalt layer deformation depth) and the total number of cycles was obtained based on the collected strain data, as shown in the figure. Figure 8 As shown. The ratio between the deformation depth and the thickness of the asphalt layer is set. =0.20, calculated at the end of the experiment =5.5mm / 50mm=0.11, and the ratio does not exceed =0.20 indicates that the asphalt layer has not reached its fatigue life under this load and ambient temperature conditions.

[0082] The experimental method for measuring the point contact stress distribution between large-particle-size graded crushed stone and asphalt pavement proposed in this invention can accurately simulate the point contact morphology between large-particle-size graded crushed stone and asphalt pavement in actual engineering without damaging the pavement structure. Through contact point identification technology, it distinguishes between stressed contact points and non-contact points, avoiding evaluation bias caused by mixed data across the entire data range. The experimental method is simple and quick. This invention simulates point contact scenarios through indoor experiments, incorporates a contact point identification mechanism to screen actual stressed contact points, and measures the stress-strain distribution and dynamic changes under different loads and temperatures, providing precise technical support for material selection and structural design of highway pavements. Based on the measured stress distribution characteristics and damage evolution laws of the actual contact points, the asphalt mixture ratio can be optimized, the structural layer thickness adjusted, or high-modulus modified materials selected. This avoids high-temperature embedding crushing and low-temperature cracking caused by stress concentration at point contact points from the design stage, thereby significantly extending the service life of the pavement, reducing the frequency and investment of later maintenance, and ultimately effectively reducing the maintenance cost throughout the entire life cycle of the project. The experimental method for measuring the point contact stress distribution between large-particle-size graded crushed stone and asphalt pavement proposed in this invention can accurately simulate the point contact morphology between large-particle-size graded crushed stone and asphalt pavement in actual engineering without damaging the pavement structure. Furthermore, by using contact point identification technology, it can distinguish between stressed contact points and non-contact points, avoiding evaluation bias caused by mixed data across the entire area. The experimental method is simple and quick.

[0083] On the other hand, this method can specifically acquire the stress-strain characteristics of contact points, determine the deformation resistance parameters of asphalt pavement adapted to point contact with large-diameter graded crushed stone, supplement the design dimensions related to the compatibility of large-diameter graded crushed stone with asphalt pavement, enhance the rutting and fatigue resistance of asphalt pavement to adapt to the point contact load of large-diameter graded crushed stone, thereby improving the bearing capacity of the pavement structure, optimizing vibration and noise reduction effects, extending the service life of the pavement, and reducing maintenance requirements. Furthermore, this invention can be tailored to local conditions, selecting asphalt pavement materials and thicknesses that match the contact performance of large-diameter graded crushed stone, and formulating asphalt pavement failure criteria based on the stress characteristics of contact points. This invention simulates point contact scenarios through indoor tests and introduces a contact point identification mechanism, which can distinguish between contact and non-contact points, reflecting real contact conditions. It establishes a correlation between contact point data and the degree of damage and service limit state between the asphalt pavement and the large-diameter crushed stone layer, directly supporting engineering decisions and realizing the accuracy of test data and the application of engineering value. This invention can promote the development of new asphalt pavement structures and materials, and drive the development of the highway engineering industry.

[0084] To better implement the stress distribution measurement method in the embodiments of the present invention, based on the stress distribution measurement method, correspondingly, as follows: Figure 9 As shown, this embodiment of the invention also provides a stress distribution measurement system 900, which includes: The acquisition module 901 is used to acquire a layered specimen simulating a road surface structure. The layered specimen consists of a fine sand layer, a crushed stone layer, and an asphalt layer from bottom to top. The crushed stone particles in the crushed stone layer form discrete point contacts with the lower surface of the asphalt layer. Sensors are distributed and embedded in a preset detection area on the lower surface of the asphalt layer. The sensors are used to collect stress data and strain data. The test acquisition module 902 is used to repeatedly apply loads to the layered specimen to simulate the cyclic action of vehicle loads, and to acquire stress and strain data from the sensor at preset time points. The identification and recording module 903 is used to identify the contact points that actually contact the crushed stone particles from all monitoring points based on the collected stress and strain data. The processing module 904 is used to obtain evaluation parameters based on the stress and strain data of the contact points, determine the degree of matching between the crushed stone layer and the asphalt layer in the point contact state according to the evaluation parameters, and provide adjustment suggestions.

[0085] The stress distribution measurement system 900 provided in the above embodiments can realize the technical solutions described in the stress distribution measurement method embodiments. The specific implementation principles of each module or unit can be found in the corresponding content in the stress distribution measurement method embodiments, which will not be repeated here.

[0086] like Figure 10 As shown, the present invention also provides an electronic device 1000. The electronic device 1000 includes a processor 1001, a memory 1002, and a display 1003. Figure 10 Only some components of the electronic device 1000 are shown, but it should be understood that it is not required to implement all the components shown, and more or fewer components may be implemented instead.

[0087] In some embodiments, processor 1001 may be a central processing unit (CPU), microprocessor, or other data processing chip, used to run program code stored in memory 1002 or process data, such as the stress distribution measurement method of the present invention.

[0088] In some embodiments, processor 1001 may be a single server or a group of servers. The server group may be centralized or distributed. In some embodiments, processor 1001 may be local or remote. In some embodiments, processor 1001 may be implemented on a cloud platform. In one embodiment, the cloud platform may include a private cloud, public cloud, hybrid cloud, community cloud, distributed cloud, intranet, multi-cloud, etc., or any combination thereof.

[0089] In some embodiments, memory 1002 may be an internal storage unit of electronic device 1000, such as a hard disk or memory of electronic device 1000. In other embodiments, memory 1002 may also be an external storage device of electronic device 1000, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc. equipped on electronic device 1000.

[0090] Furthermore, the memory 1002 may include both internal storage units of the electronic device 1000 and external storage devices. The memory 1002 is used to store application software and various types of data installed on the electronic device 1000.

[0091] In some embodiments, display 1003 may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, or an OLED (Organic Light-Emitting Diode) touchscreen. Display 1003 is used to display information from electronic device 1000 and to display a visual user interface. Components 1001-1003 of electronic device 1000 communicate with each other via a system bus.

[0092] In one embodiment, when the processor 1001 executes the stress distribution measurement program in the memory 1002, the following steps can be performed: A layered specimen simulating a road surface structure was obtained. The layered specimen consisted of a fine sand layer, a crushed stone layer, and an asphalt layer from bottom to top. The crushed stone particles in the crushed stone layer formed discrete point contacts with the lower surface of the asphalt layer. Sensors were distributed and embedded in a preset detection area on the lower surface of the asphalt layer. The sensors were used to collect stress and strain data. Cyclic loads are applied to the layered specimen to simulate the cyclic action of vehicle loads, and monitoring data from the sensors are collected at preset time points. Based on the monitoring data, the contact points that actually come into contact with the crushed stone particles are identified from all monitoring points, and the stress and strain data of the contact points are recorded. Evaluation parameters are obtained based on the stress and strain data at the contact points. The degree of matching between the crushed stone layer and the asphalt layer in the point contact state is determined according to the evaluation parameters, and adjustment suggestions are provided.

[0093] It should be understood that when the processor 1001 executes the stress distribution measurement program in the memory 1002, in addition to the functions mentioned above, it can also perform other functions, as detailed in the description of the corresponding method embodiments above.

[0094] Furthermore, the embodiments of the present invention do not specifically limit the type of the electronic device 1000 mentioned. The electronic device 1000 can be a mobile phone, tablet computer, personal digital assistant (PDA), wearable device, laptop computer, or other portable electronic device. Exemplary embodiments of portable electronic devices include, but are not limited to, portable electronic devices running iOS, Android, Microsoft, or other operating systems. The aforementioned portable electronic device can also be other portable electronic devices, such as a laptop computer with a touch-sensitive surface (e.g., a touch panel). It should also be understood that in some other embodiments of the present invention, the electronic device 1000 may not be a portable electronic device, but rather a desktop computer with a touch-sensitive surface (e.g., a touch panel).

[0095] Accordingly, this application also provides a computer-readable storage medium for storing computer-readable programs or instructions. When the programs or instructions are executed by a processor, they can implement the steps or functions of the stress distribution measurement methods provided in the above-described method embodiments.

[0096] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware (such as a processor, controller, etc.), and the computer program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.

[0097] The stress distribution measurement method, system, equipment, and medium provided by the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for measuring stress distribution, characterized in that, include: A layered specimen simulating a road surface structure was obtained. The layered specimen consisted of a fine sand layer, a crushed stone layer, and an asphalt layer from bottom to top. The crushed stone particles in the crushed stone layer formed discrete point contacts with the lower surface of the asphalt layer. Sensors were distributed and embedded in a preset detection area on the lower surface of the asphalt layer. The sensors were used to collect stress and strain data. The layered specimen was repeatedly loaded to simulate the cyclic action of vehicle load, and stress and strain data from the sensor were collected at preset time points. Based on the collected stress and strain data, the contact points that actually come into contact with the crushed stone particles are identified from all monitoring points. Evaluation parameters are obtained based on the stress and strain data at the contact points. The degree of matching between the crushed stone layer and the asphalt layer in the point contact state is determined according to the evaluation parameters, and adjustment suggestions are provided.

2. The method according to claim 1, characterized in that, The process of obtaining layered specimens simulating road surface structures includes: An outer mold is provided, and the fine sand layer is formed at the bottom of the outer mold; The crushed stone particles are laid on the fine sand layer to form the crushed stone layer; An asphalt mixture is laid on top of the crushed stone layer, and the sensors are distributed and buried at the bottom of the asphalt mixture during the molding process. After compaction, the asphalt layer with the sensors embedded inside is formed.

3. The method according to claim 1, characterized in that, The step of identifying the contact points that actually contact the crushed stone particles from all monitoring points based on the collected stress and strain data includes: Obtain the peak stress at each monitoring point in the reference specimen, and set the peak stress as the contact determination threshold for the corresponding monitoring point. Based on the collected stress data, monitoring points with stress peak values ​​greater than or equal to the contact determination threshold and durations greater than or equal to a preset duration are selected as the contact points.

4. The method according to claim 1, characterized in that, The evaluation parameters obtained based on the stress and strain data at the contact points include: Prepare at least two sets of test specimens with the same specifications as the layered specimen, and apply cyclic loads to them for different numbers of times. One set of test specimens with zero loads is used as the reference specimen. Obtain stress and strain data of the contact points identified in the reference specimen, take the stress peak value in the stress data as the reference stress peak value, and take the deformation amount corresponding to the strain data as the reference deformation amount. Based on the stress and strain data at the corresponding contact points in the test piece after applying a preset number of loads, the current peak stress and current deformation are obtained; the preset number of loads is a positive integer greater than 1. The degree of stress attenuation is determined based on the ratio of the difference between the reference stress peak and the current stress peak to the reference stress peak. The degree of deformation sensitivity is determined based on the ratio of the difference between the current deformation and the reference deformation to the preset number of times. The stress distribution characteristics are determined based on the spatial location of the contact point on the lower surface of the asphalt layer and its corresponding stress value. The evaluation parameters are obtained based on the stress attenuation degree, the deformation sensitivity, and the stress distribution characteristics.

5. The method according to claim 4, characterized in that, The step of determining the degree of matching between the crushed stone layer and the asphalt layer in a point-contact state based on the evaluation parameters and providing adjustment suggestions includes: Based on the numerical ranges of the stress attenuation degree and the deformation sensitivity, and combined with the stress distribution characteristics of the contact points, multiple evaluation levels are obtained to describe the degree of matching. Based on the evaluation level, corresponding adjustment recommendations are determined, including at least one of material selection, structural layer thickness adjustment, and compaction degree.

6. The method according to claim 1, characterized in that, The repeated application of loads to the layered specimen includes The layered specimen is placed inside the rutting apparatus, and a hardboard is placed on top of the layered specimen to distribute the wheel load of the rutting apparatus. The key parameters of the rutting instrument are set, including the wheel movement speed, wheel pressure value, ambient temperature and test duration. The rutting instrument, with the key parameters set, is started, and the wheel of the rutting instrument moves cyclically along a preset path. The set movement trajectory is a complete cycle, simulating the cyclical action of vehicle load.

7. The method according to claim 1 or 6, characterized in that, Also includes: During repeated loading, the deformation depth of the asphalt layer is determined based on the collected strain data; The deformation ratio is obtained by calculating the ratio of the deformation depth to the asphalt layer thickness; When the deformation ratio reaches a preset deformation threshold, the corresponding number of load repetitions is recorded as the fatigue life of the asphalt layer to characterize the asphalt layer's resistance to damage.

8. A stress distribution measurement system, characterized in that, include: The acquisition module is used to acquire a layered specimen simulating a road surface structure. The layered specimen consists of a fine sand layer, a crushed stone layer, and an asphalt layer from bottom to top. The crushed stone particles in the crushed stone layer form discrete point contacts with the lower surface of the asphalt layer. Sensors are distributed and embedded in a preset detection area on the lower surface of the asphalt layer. The sensors are used to collect stress data and strain data. The test acquisition module is used to repeatedly apply loads to the layered specimen to simulate the cyclic action of vehicle loads, and to acquire stress and strain data from the sensors at preset time points. The identification and recording module is used to identify the contact points that actually come into contact with the crushed stone particles from all monitoring points based on the collected stress and strain data. The processing module is used to obtain evaluation parameters based on the stress and strain data of the contact points, determine the degree of matching between the crushed stone layer and the asphalt layer in the point contact state according to the evaluation parameters, and provide adjustment suggestions.

9. An electronic device, characterized in that, Including memory and processor, among which, The memory is used to store programs; The processor, coupled to the memory, is used to execute the program stored in the memory to implement the steps in the stress distribution measurement method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, Used to store computer-readable programs or instructions, which, when executed by a processor, can perform the steps in the stress distribution measurement method according to any one of claims 1 to 7.

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