Asphalt road void ratio detection method using three-dimensional ground penetrating radar

Abstract

The invention discloses an asphalt road void ratio detection method using a three-dimensional ground penetrating radar, and belongs to the technical field of asphalt road detection.The asphalt road void ratio detection method includes the following steps of S1, a preparation stage, S2, road surface scanning, S3, water spraying operation and S4, data processing and analys.According to the scheme, sampling or destructive testing does not need to be conducted on a road surface, and damage to the road surface is avoided. Therefore, the integrity of the pavement is protected, and interference and repair cost in the detection process are reduced. The three-dimensional ground penetrating radar is used for scanning, and the porosity data of the road surface can be rapidly obtained. Compared with a traditional method, the technology has the advantages that the detection time is greatly shortened, the working efficiency is improved, and the method is particularly suitable for large-area pavement detection. Through the innovative technical means, the precision, efficiency and reliability of asphalt pavement void ratio detection are remarkably improved, and powerful technical support is provided for pavement quality evaluation and maintenance.

Description

Technical Field

[0001] The invention relates to the technical field of asphalt road detection, and in particular to an asphalt road void ratio detection method using a three-dimensional ground penetrating radar. Background Art

[0002] The void ratio of asphalt pavement is an important indicator for evaluating pavement quality. At present, the void ratio detection of asphalt pavement mainly relies on traditional laboratory sampling and analysis methods, such as core drilling method and nuclear density meter. These methods usually require the destruction of the pavement structure, which is time-consuming and costly. Three-dimensional ground penetrating radar (GPR) as a non-destructive detection technology has been widely used in pavement structure detection;

[0003] Existing detection methods may require a long time and complicated operation steps, affecting construction progress and efficiency. Especially when detecting large areas of road surface, the problem of inefficiency is particularly prominent. Sampling or destructive testing of the road surface is required, which is not only time-consuming and labor-intensive, but may also cause damage to the road surface. Therefore, in order to solve the above problems, a method for detecting the void ratio of asphalt roads using three-dimensional ground penetrating radar is crucial. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the shortcomings of the prior art, the present invention provides a method for detecting the void ratio of an asphalt road using a three-dimensional ground penetrating radar, which solves the problems existing in the above-mentioned background technology.

[0006] (II) Technical solution

[0007] To achieve the above object, the present invention provides the following technical solution: a method for detecting the void ratio of an asphalt road using a three-dimensional ground penetrating radar, comprising the following steps:

[0008] S1, preparation stage: mark the road section to be measured and make preparations;

[0009] S2. Road surface scanning: Use vehicle-mounted 3D ground penetrating radar equipment to conduct full-section scanning of the marked unsprinkled road surface;

[0010] S3. Watering operation: Use a watering truck to water the entire road section to be tested 2-3 times to ensure uniform watering. When the road surface is fully infiltrated and there is no water stain on the surface, use a 3D ground penetrating radar to perform a full-section scan;

[0011] S4. Data processing and analysis: Analyze the data collected before and after watering to obtain the difference in dielectric constants, which reflects the porosity of the road surface. The porosity of the road surface is reflected by the change in amplitude before and after watering, and the porosity of the road surface is calculated by fitting with the core sampling pavement acceptance data and the non-nuclear density meter measurement point data.

[0012] Furthermore, the preparation work in S1 is to ensure that there are no obvious obstacles in the detection area and the weather conditions are suitable for watering and radar scanning, and to prepare a sprinkler and a three-dimensional ground penetrating radar device. The sprinkler should be able to evenly cover the target road surface area.

[0013] Furthermore, the specific operation of scanning in S2 is to use the navigation positioning software RTK, use the non-nuclear density meter, measure the density of the road surface according to the points to be measured, and in order to balance the efficiency of marking and more accurately and comprehensively reflect the density changes of the road surface, the layout of the points to be measured adopts the five-point method according to the single lane, 3m in the longitudinal direction, and the specific steps are as follows:

[0014] S2.1: Equipment preparation: Use a vehicle-mounted multi-channel 3D ground penetrating radar system to ensure that all components of the equipment operate normally;

[0015] S2.2: Scanning settings: According to actual needs, adjust the radar frequency settings, dwell time and sampling interval parameters to ensure that the device can run stably during the scanning process to ensure data continuity;

[0016] S2.3: Data collection: Start the radar equipment, perform a full-section scan of the target area, and record and store the reflected radar signal data in real time;

[0017] S2.4: Data analysis: Use professional data analysis software to process the collected data, generate corresponding maps or models, and make accurate assessments of underground structures.

[0018] Furthermore, the specific operation of watering in S3 is to use a watering device to evenly water the newly built asphalt pavement, and the amount of water sprayed should be sufficient to wet the surface of the pavement without forming obvious water accumulation.

[0019] Furthermore, in S3, before watering, a three-dimensional ground penetrating radar is used to perform an initial scan on the target road surface to record initial three-dimensional ground penetrating radar data.

[0020] Furthermore, after the watering in S3 is completed, wait for a suitable time (eg, 5-10 minutes) to ensure that the water penetrates into the gaps in the road surface, and use the 3D ground penetrating radar to scan the same area again, and record the 3D ground penetrating radar data after the watering.

[0021] Furthermore, the specific data processing and analysis process in S4 is to first import the RTK data measurement points into the radar data processing software Examiner, use Examiner to mark and draw lines on the road section to be tested before and after watering, obtain the two-way travel time of the road surface, and use the constant thickness method to solve the dielectric constant of the road surface before and after watering, wherein the thickness in the constant thickness method is determined as the design value of the road surface, and a comparative analysis is performed, and the calculation of the change in the dielectric constant, and the porosity of the road surface is derived by fitting the road surface. The specific formula is:

[0022]

[0023] In the formula, H is the design value of the pavement thickness, C is the propagation speed of electromagnetic waves in the air; take 300mm / ns, ε is the relative dielectric constant, Δt is the two-way travel time of the radar wave in the pavement surface layer, and the specific steps are:

[0024] S4.1. Data collection:

[0025] Unsprinkled state: perform radar scanning on the unsprinkled road surface to obtain the initial reflection amplitude value;

[0026] Watered state: scan again after watering and record the amplitude value in the wet state;

[0027] Make sure to scan twice at the same location and depth for comparative analysis.

[0028] S4.2 Data processing:

[0029] Extract amplitude value: Extract the amplitude value of corresponding points or areas from two scan data.

[0030] Calculate the rate of change: Calculate the rate of change of the amplitude value. The calculation formula is:

[0031]

[0032] Where ΔA is the relative change percentage, A wet is the amount in the wet state, A dry It is the quantity in dry state, and the rate of change reflects the degree of change of void ratio;

[0033] Filtering and denoising: Smooth the data, remove noise interference, and highlight trend changes.

[0034] S4.3. Void ratio estimation: Calibration experiment: simulate pavements with different void ratios in the laboratory, obtain the amplitude value changes by scanning before and after watering, and establish the quantitative relationship between void ratio and amplitude value;

[0035] Actual data estimation: Substitute the on-site amplitude change rate into the calibration model to calculate the void ratio.

[0036] Furthermore, in S2.4, the specific data analysis process is as follows:

[0037] S2.4.1: Image preprocessing: Enhance the image effect, process the radar image, and improve the image clarity and contrast;

[0038] S2.4.2: Cause analysis of damage: Combine the radar image with the design and construction data of the road to analyze the cause of the damage;

[0039] S2.4.3: Quantitative parameter analysis: Use professional data analysis software to conduct quantitative analysis of disease depth, size and other parameters to accurately assess the disease status;

[0040] S2.4.4: Comprehensive interpretation and judgment: Observe the abnormal body from different sections to obtain more accurate and reliable interpretation results. The algorithm formula is:

[0041]

[0042] Among them, T represents comprehensive interpretation and L represents profile interpretation. The specific meaning is that comprehensive interpretation T is obtained by combining each profile interpretation L with its corresponding weight w i Multiplying and then summing all these products gives the profile interpretation L as a function of I′(x,y) and R.

[0043] (III) Beneficial effects

[0044] The present invention provides a method for detecting the void ratio of an asphalt road using a three-dimensional ground penetrating radar, which has the following beneficial effects:

[0045] By eliminating the need for sampling or destructive testing of the road surface, damage to the road surface is avoided. This not only protects the integrity of the road surface, but also reduces interference and repair costs during the detection process. Using 3D ground penetrating radar for scanning, the porosity data of the road surface can be quickly obtained. Compared with traditional methods, this technology greatly shortens the detection time and improves work efficiency, and is particularly suitable for the detection of large areas of road surface. Through innovative technical means, the accuracy, efficiency and reliability of asphalt pavement porosity detection have been significantly improved, providing strong technical support for pavement quality assessment and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 A method flow chart of a method for detecting void ratio of an asphalt road using a three-dimensional ground penetrating radar according to the present invention;

[0047] Figure 2 is a relative position diagram of the RTK and non-nuclear density meter in Example 1 of the present invention;

[0048] Figure 3This is a schematic diagram of the marking position in Example 1 of the present invention;

[0049] Figure 4 Import the Examiner software diagram for the RTK measurement points in Example 1 of the present invention;

[0050] Figure 5 A data graph is derived for the non-nuclear density instrument in Example 1 of the present invention;

[0051] Figure 6 The road amplitude data diagram in Example 1 of the present invention;

[0052] Figure 7 This is a diagram of the amplitude value software output data in Example 1 of the present invention. DETAILED DESCRIPTION

[0053] In order to make the technical solution of the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0054] Example 1

[0055] As shown in the figure, according to one aspect of the present invention, a technical solution is provided: a method for detecting the void ratio of an asphalt road using a three-dimensional ground penetrating radar, comprising the following steps:

[0056] Step 1, preparation stage: mark the road section to be measured and make preparations. The preparations are to ensure that there are no obvious obstacles in the detection area and that the weather conditions are suitable for watering and radar scanning. Prepare the sprinkler and 3D ground penetrating radar equipment. The sprinkler should be able to evenly cover the target road area.

[0057] Step 2: Road surface scanning: The marked section of the road without watering is scanned in full section using a vehicle-mounted 3D ground penetrating radar device. The specific scanning operation is to use the navigation positioning software RTK and a non-nuclear density meter to measure the density of the road surface according to the points to be measured. In order to balance the efficiency of dot marking and more accurately and comprehensively reflect the density changes of the road surface, the layout of the points to be measured adopts the five-point method according to a single lane, with a longitudinal distance of 3m. The specific relative positions of the RTK and the non-nuclear density meter are as follows: Figure 2 As shown, the specific steps are as follows:

[0058] S2.1: Equipment preparation: Use a vehicle-mounted multi-channel 3D ground penetrating radar system to ensure that all components of the equipment operate normally;

[0059] S2.2: Scanning settings: According to actual needs, adjust the radar frequency settings, dwell time and sampling interval parameters to ensure that the device can run stably during the scanning process to ensure data continuity;

[0060] S2.3: Data collection: Start the radar equipment, perform a full-section scan of the target area, and record and store the reflected radar signal data in real time;

[0061] S2.4: Data analysis: Use professional data analysis software to process the collected data, generate corresponding maps or models, and accurately evaluate the underground structure. The specific data analysis process is as follows:

[0062] S2.4.1: Image preprocessing: Enhance the image effect, process the radar image, and improve the image clarity and contrast;

[0063] S2.4.2: Cause analysis of damage: Combine the radar image with the design and construction data of the road to analyze the cause of the damage;

[0064] S2.4.3: Quantitative parameter analysis: Use professional data analysis software to conduct quantitative analysis of disease depth, size and other parameters to accurately assess the disease status;

[0065] S2.4.4: Comprehensive interpretation and judgment: Observe the abnormal body from different sections to obtain more accurate and reliable interpretation results. The algorithm formula is:

[0066]

[0067] Among them, T represents comprehensive interpretation and L represents profile interpretation. The specific meaning is that comprehensive interpretation T is obtained by combining each profile interpretation L with its corresponding weight w i Multiplying and then summing all these products gives the profile interpretation L as a function of I′(x,y) and R.

[0068] Step 3: Watering operation: Use a watering truck to water the entire road section to be tested 2-3 times to ensure uniform watering. When the road surface is fully infiltrated and there is no water stain on the surface, use the 3D ground penetrating radar to scan the entire section. The specific operation of watering is to use a watering device to evenly water the newly built asphalt road surface. The amount of water sprayed should be enough to wet the surface of the road surface, but no obvious water accumulation should be formed. Before watering, use the 3D ground penetrating radar to perform an initial scan of the target road surface, record the initial 3D ground penetrating radar data, wait for an appropriate time (for example, 5-10 minutes) to ensure that the water penetrates into the gaps in the road surface, and use the 3D ground penetrating radar to scan the same area again, and record the 3D ground penetrating radar data after watering. The specific RTK measurement points are imported into the Examiner software as shown in the figure below. Figure 3 and Figure 4 shown.

[0069] Step 4, data processing and analysis: Analyze the data collected before and after watering to obtain the difference in dielectric constant, which reflects the porosity of the road surface. The porosity of the road surface is reflected by the change in amplitude before and after watering, and the porosity of the road surface is calculated by fitting with the core sampling road surface acceptance data and the non-nuclear density meter measurement point data. The specific data processing and analysis process is to first import the RTK data measurement points into the radar data processing software Examiner, use Examiner to mark and draw lines on the road section to be tested before and after watering, and obtain the two-way travel time of the road surface. The dielectric constant of the road surface before and after watering is solved by the constant thickness method, in which the thickness in the constant thickness method is determined as the design value of the road surface, and a comparative analysis is performed. The calculation of the change in dielectric constant is used to derive the porosity of the road surface through the fitting road. The specific formula is:

[0070]

[0071] Where H is the design value of the pavement thickness, C is the propagation speed of electromagnetic waves in the air, which is 300 mm / ns, ε is the relative dielectric constant, and Δt is the two-way travel time of the radar wave in the pavement surface layer. The specific data derived from the non-nuclear density meter are as follows: Figure 5 As shown, the specific steps are:

[0072] S4.1. Data collection:

[0073] Unsprinkled state: perform radar scanning on the unsprinkled road surface to obtain the initial reflection amplitude value;

[0074] Watered state: scan again after watering and record the amplitude value in the wet state;

[0075] Make sure to scan twice at the same location and depth for comparative analysis.

[0076] S4.2 Data processing:

[0077] Extract amplitude value: Extract the amplitude value of corresponding points or areas from two scan data.

[0078] Calculate the rate of change: Calculate the rate of change of the amplitude value. The calculation formula is:

[0079]

[0080] Where ΔA is the relative change percentage, A wet is the amount in the wet state, A dry It is the quantity in dry state, and the rate of change reflects the degree of change of void ratio;

[0081] Filtering and denoising: Smooth the data, remove noise interference, and highlight trend changes.

[0082] S4.3. Void ratio estimation: Calibration experiment: simulate pavements with different void ratios in the laboratory, obtain the amplitude value changes by scanning before and after watering, and establish the quantitative relationship between void ratio and amplitude value;

[0083] Actual data estimation: Substitute the on-site amplitude change rate into the calibration model to calculate the void ratio.

[0084] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0085] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for detecting void ratio of asphalt roads using three-dimensional ground penetrating radar, characterized in that: The following steps are involved: S1, preparation stage: mark the road section to be measured and make preparations; S2. Road surface scanning: Use vehicle-mounted 3D ground penetrating radar equipment to conduct full-section scanning of the marked unsprinkled road surface; S3. Watering operation: Use a watering truck to water the entire road section to be tested 2-3 times to ensure uniform watering. When the road surface is fully infiltrated and there is no water stain on the surface, use a 3D ground penetrating radar to perform a full-section scan; S4. Data processing and analysis: Analyze the data collected before and after watering to obtain the difference in dielectric constants, which reflects the porosity of the road surface. The porosity of the road surface is reflected by the change in amplitude before and after watering, and the porosity of the road surface is calculated by fitting with the core sampling pavement acceptance data and the non-nuclear density meter measurement point data.

2. The method for detecting void ratio of asphalt road using three-dimensional ground penetrating radar according to claim 1, characterized in that: The preparation work in S1 is to ensure that there are no obvious obstacles in the detection area and that the weather conditions are suitable for watering and radar scanning. A sprinkler device and a three-dimensional ground penetrating radar device are prepared. The sprinkler device should be able to evenly cover the target road surface area.

3. The method for detecting void ratio of asphalt road using three-dimensional ground penetrating radar according to claim 1, characterized in that: The specific operation of scanning in S2 is to use the navigation positioning software RTK and a non-nuclear density meter to measure the density of the road surface according to the points to be measured. In order to balance the efficiency of dot marking and more accurately and comprehensively reflect the density changes of the road surface, the layout of the points to be measured adopts the five-point method according to a single lane, with a longitudinal distance of 3m. The specific steps are as follows: S2.1: Equipment preparation: Use a vehicle-mounted multi-channel 3D ground penetrating radar system to ensure that all components of the equipment operate normally; S2.2: Scanning settings: According to actual needs, adjust the radar frequency settings, dwell time and sampling interval parameters to ensure that the device can run stably during the scanning process to ensure data continuity; S2.3: Data collection: Start the radar equipment, perform a full-section scan of the target area, and record and store the reflected radar signal data in real time; S2.4: Data analysis: Use professional data analysis software to process the collected data, generate corresponding maps or models, and make accurate assessments of underground structures.

4. The method for detecting void ratio of asphalt road using three-dimensional ground penetrating radar according to claim 1, characterized in that: The specific operation of watering in S3 is to use a watering device to evenly water the newly built asphalt pavement. The amount of water sprayed should be sufficient to wet the surface of the pavement without forming obvious water accumulation.

5. The method for detecting void ratio of asphalt road using three-dimensional ground penetrating radar according to claim 4, characterized in that: In S3, before watering, a three-dimensional ground penetrating radar is used to perform an initial scan on the target road surface, and initial three-dimensional ground penetrating radar data is recorded.

6. The method for detecting void ratio of asphalt road using three-dimensional ground penetrating radar according to claim 5, characterized in that: After the watering in S3 is completed, wait for a suitable time to ensure that the water penetrates into the gaps in the road surface, and use the three-dimensional ground penetrating radar to scan the same area again to record the three-dimensional ground penetrating radar data after the watering.

7. The method for detecting void ratio of asphalt road using three-dimensional ground penetrating radar according to claim 6, characterized in that: The specific data processing and analysis process in S4 is to first import the RTK data measurement points into the radar data processing software Examiner, use Examiner to mark and draw lines on the road section to be tested before and after watering, obtain the two-way travel time of the road surface, and use the constant thickness method to solve the dielectric constant of the road surface before and after watering, wherein the thickness in the constant thickness method is determined as the road surface design value, and a comparative analysis is performed, and the calculation of the change in the dielectric constant is used to deduce the porosity of the road surface by fitting the road surface. The specific formula is: In the formula, H is the design value of the pavement thickness, C is the propagation speed of electromagnetic waves in the air, which is 300 mm / ns, ε is the relative dielectric constant, and Δt is the two-way travel time of the radar wave in the pavement surface layer. The specific steps are: S4.

1. Data collection: Unsprinkled state: perform radar scanning on the unsprinkled road surface to obtain the initial reflection amplitude value; Watered state: scan again after watering and record the amplitude value in the wet state; Make sure to scan twice at the same location and depth for comparative analysis. S4.2 Data processing: Extract amplitude value: Extract the amplitude value of corresponding points or areas from two scan data. Calculate the rate of change: Calculate the rate of change of the amplitude value. The calculation formula is: Where ΔA is the relative change percentage, A wet is the amount in the wet state, A dry It is the quantity in dry state, and the rate of change reflects the degree of change of void ratio; Filtering and denoising: Smooth the data, remove noise interference, and highlight trend changes. S4.

3. Void ratio estimation: Calibration experiment: simulate pavements with different void ratios in the laboratory, obtain the amplitude value changes by scanning before and after watering, and establish the quantitative relationship between void ratio and amplitude value; Actual data estimation: Substitute the on-site amplitude change rate into the calibration model to calculate the void ratio.

8. The method for detecting void ratio of asphalt road using three-dimensional ground penetrating radar according to claim 3, characterized in that: In S2.4, the specific data analysis process is as follows: S2.4.1: Image preprocessing: Enhance the image effect, process the radar image, and improve the image clarity and contrast; S2.4.2: Cause analysis of damage: Combine the radar image with the design and construction data of the road to analyze the cause of the damage; S2.4.3: Quantitative parameter analysis: Use professional data analysis software to conduct quantitative analysis of disease depth, size and other parameters to accurately assess the disease status; S2.4.4: Comprehensive interpretation and judgment: Observe the abnormal body from different sections to obtain more accurate and reliable interpretation results. The algorithm formula is: T=∑ i＝1 nw i ·L i (I′(x,y),R) Among them, T represents comprehensive interpretation and L represents profile interpretation. The specific meaning is that comprehensive interpretation T is obtained by combining each profile interpretation L with its corresponding weight w i Multiplying and then summing all these products gives the profile interpretation L as a function of I′(x,y) and R.

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