Thickness test method of highway asphalt pavement surface based on 3D holographic detection technology

Abstract

The present invention discloses a method for testing the surface thickness of a highway asphalt pavement based on three-dimensional holographic detection technology. The method calculates the relative elevation at the full-section position of the pavement at the measuring point i through three-dimensional detection data; obtains the designed cross slope of the road section and the surface thickness control parameters at the corresponding measuring point i, and calculates the elevation of the top surface of the surface layer after the construction of the corresponding measuring point i is completed; calculates the thickness of the full-section surface layer after the construction is completed; and calculates the qualified number of measuring points m to obtain the qualified rate of the pavement surface layer thickness after the construction is completed. The method of the present application can provide reasonable control parameters for construction, belongs to a pre-control means, has a large application range, and is a simple, easy and objective test method.

Description

Technical Field

[0001] The invention relates to the field of road surface testing methods, and in particular to a method for testing the thickness of a highway asphalt road surface based on three-dimensional holographic detection technology. Background Art

[0002] The surface layer thickness is an important acceptance indicator for asphalt pavement and an important control link in road construction. The qualified rate and uniformity of the surface layer thickness directly determine the quality of asphalt pavement construction and have an important impact on the durability of the pavement. Therefore, the surface layer thickness is controlled within a reasonable range during construction to ensure that the pavement thickness meets the design requirements. However, there is currently great uncertainty in the control of surface layer thickness for pavement reconstruction and maintenance engineering pavement construction. After years of use, due to road settlement, maintenance leveling and additional surface layers, the existing pavement elevation has a large fluctuation. The traditional thickness control method is still used during the construction of pavement reconstruction and maintenance engineering pavement, which inevitably causes a large unevenness in the thickness of the additional surface layer.

[0003] Engineering practice shows that the thickness of the surface layer is an important control parameter for construction. The current method is mainly based on the empirical method. Construction is carried out according to the designed thickness. A reasonable construction thickness is determined through the test section, and then the thickness is used as the control parameter for the entire project. For newly built expressways, this method is applicable because the elevation plane fluctuation of the newly built pavement is not large. However, for the pavement of the expanded highway and maintenance project, this method has great limitations. On the one hand: due to the fluctuation of the elevation of the expanded highway and maintenance project pavement, under the control of the same surface layer thickness, for points with higher elevations of the underlying layer, the surface layer thickness is insufficient. Subject to the influence of the maximum nominal particle size of the asphalt mixture, the surface void ratio after construction is large, and most of the aggregates in the asphalt mixture are crushed. On the other hand: the surface layer thickness is an important acceptance indicator. Due to the fluctuation of the elevation of the underlying layer, the surface layer thickness after construction is insufficient or too thick, resulting in material losses for the construction unit and unqualified thickness acceptance indicators.

[0004] Industry practitioners have recognized this problem. However, due to the lack of a suitable thickness determination method and the fact that construction units are not clear about how to adjust thickness control parameters in time during construction, the thickness of a part of the road surface after construction is insufficient, and gravel in some locations is severely crushed, resulting in large-scale rework. After a period of use, the asphalt pavement of a part of the road surface shows early damage, and insufficient thickness is one of the important reasons. Therefore, a method for determining the thickness of the surface layer of a highway asphalt pavement based on three-dimensional holographic detection technology is invented. The relative elevation is determined by three-dimensional holographic detection of the entire cross-section of the underlying layer. On this basis, the thickness qualification rate of the entire cross-section under different thickness conditions is scientifically calculated to ensure that the thickness is qualified after construction is completed, and it is very necessary to avoid rework and construction quality problems. Summary of the invention

[0005] In view of the above problems, the present invention aims to provide a method for testing the thickness of a highway asphalt pavement surface layer based on three-dimensional holographic detection technology.

[0006] To achieve the technical purpose, the scheme of the present invention is: a method for testing the thickness of a highway asphalt pavement surface layer based on three-dimensional holographic detection technology, and the specific steps are as follows:

[0007] The three-dimensional detection data of the entire section of the lower supporting pavement of the road section is obtained by the on-board three-dimensional pavement acquisition equipment; the relative elevation data of the entire section of the road surface is calculated by the three-dimensional detection data, and the surface layer top surface elevation data is calculated according to the road section design, and the surface layer thickness data is calculated by the relative elevation data and the surface layer top surface elevation data; finally, the qualified rate of the surface layer thickness is calculated based on the surface layer thickness data, and the qualified rate is made greater than the design threshold by modifying the specified parameters.

[0008] As a preferred embodiment, the relative elevation data is calculated by using the three-dimensional detection data to calculate the relative elevation β at the full section of the road surface at the measuring point i. i , and at the same time, the measuring point spacing b is selected based on the cross-sectional length characteristic of measuring point i to obtain measuring point i+1, where i = 1 to n;

[0009] The surface layer top elevation data is obtained by obtaining the design cross slope γ of the road section and the surface layer thickness control parameter ɑ corresponding to the measuring point i i , calculate and obtain the top surface elevation λ of the corresponding measuring point i after construction is completed i ;

[0010] Calculate the full section surface thickness h in the layer thickness data after construction is completed i ,h i =λ i -β i , when h i ≥h 设计 When , the surface layer thickness is qualified; where h 设计 is the designed thickness of the surface layer; the number of qualified measuring points is counted as m, and the qualified rate of the pavement surface layer thickness after the construction is completed is calculated as б, б=m / n.

[0011] Preferably, the road surface three-dimensional acquisition equipment adopts a technology based on digital holography, uses a CCD camera to collect data from the interference fringe data projected by the laser on the road surface, and performs phase data analysis on the road surface elevation interference fringe deformation data to restore and establish a three-dimensional data model of the road surface, and then extracts the β at the full section position of the road surface at the measuring point i before the unpaved asphalt road surface structure layer from the three-dimensional road surface model. i .

[0012] Preferably, the road surface three-dimensional acquisition equipment performs data acquisition in a full-section elevation acquisition mode, and the vehicle speed during acquisition is 20-100km / h; the acquisition period is at night, and when the ambient light intensity exceeds a threshold, data acquisition is stopped to reduce the interference of external light on the road surface elevation data; the acquisition accuracy of the three-dimensional detection data is less than or equal to 1mm.

[0013] As a preferred method, the elevation reference line position of the paver before construction is obtained, and the first position of the paver is recorded as the reference line L 01 , the first position of the paver is recorded as i = k, then the reference line L 01 The relative elevation at the location is β k The second position of the paver is recorded as the reference line L 02 , the second position of the paver is recorded as i = m, then the baseline L 02 The relative elevation at the location is β m ; cross slope γ=(β m -β k ) / (L 01 -L 02 ).

[0014] As a preferred method, calculate the top elevation of the surface layer after construction is completed i =h i +β i , where h i = i *h 设计 The cross slope is a fixed value on the same section. The design cross slope γ is determined according to the engineering design needs. After the construction is completed, the first position of the paver is still recorded as the reference line L 01 , the position of measuring point i in the paving area is recorded as L i , the top surface elevation of the surface layer at measuring point i satisfies: λ i =γ*(L 01 -L i )+λ k .

[0015] As a preference, when the surface layer thickness is h 0 When the thickness qualification rate is less than 设计最低值 When the surface thickness control does not meet the design threshold, the surface thickness control parameter ɑ is adjusted during construction calculation. i , when adjusting, follow ɑ i+1 = i +c, c is the adjustment constant, the value range of c is 0.01-0.10; until the surface thickness h 0 Meets design requirements.

[0016] Preferably, the measurement point spacing b ranges from 0.1 to 1 meter; the design cross slope γ ranges from -5% to 5%.

[0017] The beneficial effects of the present invention are as follows: the method of the present application determines the relative elevation of the lower bearing layer through three-dimensional holographic detection of the entire section, and on this basis, by scientifically calculating the thickness qualification rate b of the entire section under different thickness conditions, the rationality of the paving thickness control parameters of the paver and the qualification rate of the entire section after paving are determined before construction; the method of the present application determines the relative elevation of the lower bearing layer based on three-dimensional holographic detection technology, which is more operational and objective, has high operating efficiency, and the accuracy can reach within 1 mm; the method of the present application can provide reasonable control parameters for construction, belongs to a pre-control means, has a large application range, and is a simple, easy and objective test method; at the same time, the method of the present application accurately controls the construction thickness, and has the advantage of accurate control compared with the existing estimation method; then the present application can also save construction materials, and under the condition of meeting the design requirements, saves the materials required for the project construction, thereby saving the project construction cost; the method of the present application greatly improves the project qualification rate guarantee, and compared with the traditional detection with single-point representative detection, it can achieve the full-section estimated qualification rate, and the guarantee coefficient for construction quality is significantly improved; finally, the method of the present application can also save construction time. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A reference schematic diagram of a cross section of the present invention;

[0019] Figure 2 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] like Figure 1-2 As shown, the specific embodiment of the present invention is a method for testing the thickness of a highway asphalt pavement surface layer based on three-dimensional holographic detection technology, and the specific steps are as follows:

[0022] S1. Test the relative elevation of the entire section of the underlying layer; obtain the three-dimensional detection data of the entire section of the underlying pavement of the road section through the vehicle-mounted three-dimensional road surface acquisition equipment; calculate the relative elevation β of the entire section of the pavement at the measuring point i through the three-dimensional detection data i , and at the same time, the measuring point spacing b is selected based on the cross-sectional length characteristic of the measuring point i, and the measuring point i+1 is obtained, where i=1~n; wherein the value range of the measuring point spacing b is 0.1-1 meter;

[0023] S2, determine the elevation reference line position of the paver; obtain the elevation reference line position of the paver, and the first position of the paver is recorded as the reference line L 1, the first position of the paver is recorded as i = k, then the reference line L 01 The relative elevation at the location is β k The second position of the paver is recorded as the reference line L 02 , the second position of the paver is recorded as i = m, then the baseline L 02 The relative elevation at the location is β m ; cross slope γ=(β m -β k ) / (L 01 -L 02 ).

[0024] S3: Determine the elevation of the entire section after construction is completed based on the designed cross slope and the baseline elevation; obtain the designed cross slope γ of the road section and the surface thickness control parameter ɑ at the corresponding measuring point i i , calculate and obtain the top surface elevation λ of the corresponding measuring point i after construction is completed i ; The design cross slope γ ranges from -5% to 5%.

[0025] S4: Determine the qualified rate of the full section surface thickness after construction is completed; calculate the full section surface thickness h after construction is completed i ,h i =λ i -β i , when h i ≥h 设计 When , the surface layer thickness is qualified; where h is 设计 Design thickness of the surface layer; count the number of qualified measuring points as m, and calculate the qualified rate of pavement surface thickness after construction, б, б = m / n.

[0026] S5: Adjust the thickness of the asphalt pavement surface layer according to the thickness qualification rate until the asphalt surface layer thickness qualification rate meets the specified requirements; when the surface layer thickness is h 0 When the thickness qualification rate is less than the minimum design value, it is considered that the surface thickness control does not meet the design requirements. In this case, the surface thickness control parameter ɑ is adjusted during construction. i , until the surface thickness h 0 Meets the requirements. At the same time, since the designed cross slope γ needs to be implemented according to the engineering design, it is a fixed value γ, and the adjusted surface top elevation needs to meet the following requirements.

[0027] Calculate the top elevation of the surface layer after construction is completed i =h i +β i , where h i = i *h 设计 (Generally iThe range of values ​​is 1.20-1.50). The cross slope is a fixed value on the same section, and the design cross slope γ is determined according to the engineering design requirements. After the construction is completed, the first position of the paver is still recorded as the reference line L 01 , the position of measuring point i in the paving area is recorded as L i , the top surface elevation of the surface layer at measuring point i satisfies: λ i =γ*(L 01 -L i )+λ k .

[0028] Embodiment 1:

[0029] The bridge deck project in a certain H city is a cement concrete beam bridge with a road width of 12m. Due to poor quality control of the integral layer during construction, the elevation of the integral layer of the bridge deck has large fluctuations. Therefore, the elevation of the integral layer was detected using three-dimensional holographic detection technology. According to the 1m measurement point spacing of the section, 1 elevation data was output, and the elevation data of a certain section was intercepted. The thickness of the middle surface layer was 6mm, the cross slope of the section was 2%, and the paver reference line L1 was 4m at the section, as shown in the following table.

[0030] Table 1 Test of the elevation of the integrated layer section of a cement concrete beam bridge

[0031]

[0032] The appropriate surface layer thickness control parameters and the results of control according to traditional control methods and different thickness control parameters are shown in the following table.

[0033] Table 2 Elevation of a cement concrete beam bridge under different control conditions of the middle surface layer thickness of the integral layer

[0034]

[0035] Table 2 Full section thickness and qualified rate of a cement concrete beam bridge under different thickness control conditions of the middle surface layer of the integral layer

[0036]

[0037] From the above, it can be seen that, when the conventional control method is used and the thickness is controlled according to the design requirement of 0.06 mm, the qualified rate of the section thickness is only 30.8%, and when the thickness is controlled according to 7.0 mm, the qualified rate of the thickness is 53.4%. Therefore, according to the method proposed by the present invention, the appropriate thickness control parameters of the middle surface layer can be obtained to improve the qualified rate of the surface layer thickness.

[0038] Implementation Case 2

[0039] The bridge deck project in a certain H city is a cement concrete beam bridge. The design thickness of the middle surface layer is 6cm. The traditional method is used to determine the construction thickness. Considering the poor flatness of the bridge deck integration layer, in order to ensure the construction thickness, the overall construction thickness selected during construction is controlled at 6.5cm. After the construction is completed, 5 points are selected for core sampling verification, and the thickness qualification rate is determined to be 80%. However, according to this method, the construction thickness control is first tested to determine the relative elevation of the lower bearing layer integration layer, and then simulated calculations are performed according to different thicknesses to determine the qualification rate. Finally, when the qualification rate is 80%, the construction thickness can be controlled at 6.2cm. Therefore, the comparison of different methods is shown in the following table:

[0040] Table 3 Comparison of construction thickness determined by different methods

[0041]

[0042] According to Table 3 above, the method of this application has the following advantages. The first is the precise control of construction thickness. Compared with the existing construction method based on experience estimation, it has the advantage of precise control. Second, it saves construction materials. Under the condition of meeting the design requirements, it saves the materials required for project construction, thereby saving the project construction cost; third, the project qualification rate is greatly improved. Compared with the traditional inspection based on single-point representative inspection, the method of this application can achieve the estimated qualification rate of the entire section, and the guarantee coefficient for construction quality is significantly improved. Fourth, the project construction time is saved. Due to the reduction in material consumption, the material production time is saved, thereby saving the construction period.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any slight modification, equivalent substitution and improvement made to the above embodiment based on the technical essence of the present invention should be included in the protection scope of the technical solution of the present invention.

Claims

1. A method for testing the thickness of a highway asphalt pavement surface layer based on three-dimensional holographic detection technology, characterized in that: The specific steps are as follows: The three-dimensional detection data of the entire section of the lower supporting pavement of the road section is obtained by the on-board three-dimensional pavement acquisition equipment; the relative elevation data of the entire section of the road surface is calculated by the three-dimensional detection data, and the surface layer top surface elevation data is calculated according to the road section design, and the surface layer thickness data is calculated by the relative elevation data and the surface layer top surface elevation data; finally, the qualified rate of the surface layer thickness is calculated based on the surface layer thickness data, and the qualified rate is made greater than the design threshold by modifying the specified parameters.

2. The method for testing the thickness of a highway asphalt pavement surface layer based on three-dimensional holographic detection technology according to claim 1 is characterized in that: The relative elevation β of the full section of the road surface at the measuring point i is calculated by the three-dimensional detection data in the relative elevation data. i , and at the same time, the measuring point spacing b is selected based on the cross-sectional length characteristic of measuring point i to obtain measuring point i+1, where i = 1 to n; The surface layer top elevation data is obtained by obtaining the design cross slope γ of the road section and the surface layer thickness control parameter ɑ corresponding to the measuring point i i , calculate and obtain the top surface elevation λ of the corresponding measuring point i after construction is completed i ; Calculate the full section surface thickness h in the layer thickness data after construction is completed i ,h i =λ i -β i , when h i ≥h 设计 When , the surface layer thickness is qualified; where h 设计 is the designed thickness of the surface layer; the number of qualified measuring points is counted as m, and the qualified rate of the pavement surface layer thickness after the construction is completed is calculated as б, б=m / n.

3. The method for testing the thickness of a highway asphalt pavement surface layer based on three-dimensional holographic detection technology according to claim 2 is characterized in that: The road surface 3D acquisition equipment adopts the technology based on digital holography, uses CCD camera to collect the interference fringe data projected by laser on the road surface, and performs phase data analysis on the road surface elevation interference fringe deformation data to restore and establish a 3D data model of the road surface, and then extracts the β at the full section position of the road surface at the measuring point i before the unpaved asphalt road surface structure layer from the 3D road surface model. i .

4. The method for testing the thickness of a highway asphalt pavement surface layer based on three-dimensional holographic detection technology according to claim 3 is characterized in that: The road surface three-dimensional acquisition equipment collects data in accordance with the full-section elevation acquisition method, and the vehicle speed during acquisition is 20-100km / h; the acquisition period is at night, and when the ambient light intensity exceeds the threshold, the data acquisition work is stopped to reduce the interference of external light on the road surface elevation data; the acquisition accuracy of the three-dimensional detection data is less than or equal to 1mm.

5. The method for testing the thickness of a highway asphalt pavement surface layer based on three-dimensional holographic detection technology according to claim 2 is characterized in that: Get the elevation reference line position of the paver before construction. The first position of the paver is recorded as the reference line L 01 , the first position of the paver is recorded as i = k, then the reference line L 01 The relative elevation at the location is β k The second position of the paver is recorded as the reference line L 02 , the second position of the paver is recorded as i = m, then the baseline L 02 The relative elevation at the location is β m ; cross slope γ=(β m -β k ) / (L 01 -L 02 ).

6. The method for testing the thickness of a highway asphalt pavement surface layer based on three-dimensional holographic detection technology according to claim 5 is characterized in that: Calculate the top elevation of the surface layer after construction is completed i =h i +β i , where h i = i *h 设计 The cross slope is a fixed value on the same section. The design cross slope γ is determined according to the engineering design needs. After the construction is completed, the first position of the paver is still recorded as the reference line L 01 , the position of measuring point i in the paving area is recorded as L i , the top surface elevation of the surface layer at measuring point i satisfies: λ i =γ*(L 01 -L i )+λ k .

7. The method for testing the thickness of a highway asphalt pavement surface layer based on three-dimensional holographic detection technology according to claim 6 is characterized in that: When the surface layer thickness is h0, if the thickness qualification rate is less than 设计最低值 When the surface thickness control does not meet the design threshold, the surface thickness control parameter ɑ is adjusted during construction calculation. i , when adjusting, follow ɑ i+1 = i +c, c is an adjustment constant, and the value range of c is 0.01-0.10; until the surface layer thickness h0 meets the design requirements.

8. The method for testing the thickness of a highway asphalt pavement surface layer based on three-dimensional holographic detection technology according to claim 2 is characterized in that: The value range of the measuring point spacing b is 0.1-1 meter; the value range of the design cross slope γ is -5% to 5%.

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