阅读说明：本技术 一种基于探地雷达的沥青复合碎石封层厚度检测方法 (Method for detecting thickness of asphalt composite gravel seal layer based on ground penetrating radar ) 是由 刘凯 童健航 王大为 罗桑 庄远 笪艺 徐晓倩 张玄成 黄沐阳 许培欣 于 2021-03-24 设计创作，主要内容包括：本发明公开了一种基于探地雷达的沥青复合碎石封层厚度检测方法,包括以下步骤：步骤一、制作4-6个沥青复合碎石封层室内试件；步骤二、用常规厚度检测法对制作好的试件进行测厚；步骤三、用基于探地雷达检测法对制作好的试件进行测厚；步骤四、基于步骤二和步骤三,对数据进行归一化处理,通过公式得到相应的厚度修正系数；步骤五、基于上述步骤,提出介电常数经验回归公式。本发明减少甚至消除单纯由探地雷达检测法得到的路面厚度误差,大大提高了传统探地雷达检测方法的检测精度,达到无损检测的目的,避免了钻芯之后修复的问题,消除了钻芯导致病害的可能性,指导沥青复合碎石封层的施工,保证施工质量,提高了厚度修正系数的精确度。(The invention discloses a method for detecting the thickness of an asphalt composite macadam seal coat based on a ground penetrating radar, which comprises the following steps: firstly, manufacturing 4-6 asphalt composite crushed stone seal layer indoor test pieces; step two, measuring the thickness of the manufactured test piece by using a conventional thickness detection method; thirdly, measuring the thickness of the manufactured test piece by using a ground penetrating radar-based detection method; step four, based on the step two and the step three, carrying out normalization processing on the data, and obtaining a corresponding thickness correction coefficient through a formula; and step five, based on the steps, providing an empirical dielectric constant regression formula. The invention reduces or even eliminates the pavement thickness error obtained by a ground penetrating radar detection method, greatly improves the detection precision of the traditional ground penetrating radar detection method, achieves the aim of nondestructive detection, avoids the problem of repairing after core drilling, eliminates the possibility of diseases caused by core drilling, guides the construction of the asphalt composite crushed stone seal, ensures the construction quality and improves the precision of the thickness correction coefficient.)

1. The invention relates to a method for detecting the thickness of an asphalt composite macadam seal coat based on a ground penetrating radar, which is characterized by comprising the following steps of:

firstly, manufacturing 4-6 asphalt composite crushed stone seal layer indoor test pieces;

step two, measuring the thickness of the manufactured test piece by using a conventional thickness detection method;

thirdly, measuring the thickness of the manufactured test piece by using a ground penetrating radar-based detection method;

step four, based on the step two and the step three, carrying out normalization processing on the data, and obtaining a corresponding thickness correction coefficient through a formula;

step five, based on the steps, providing an empirical regression formula of the dielectric constant, and predicting the thickness of the seal layer before construction;

step six, after the construction of the asphalt composite crushed stone seal is finished, detecting the thickness of the on-site asphalt composite crushed stone seal by using a ground penetrating radar detection method, and correcting by using a corresponding correction coefficient;

step seven, comparing the predicted thickness obtained in the step six with the actually measured thickness obtained in the step seven, calculating the relative error of the predicted thickness and checking the accuracy of the actually measured thickness;

step eight, if the relative error is less than-2%, taking remedial measures;

step three, the thickness correction coefficient formula is

In the formula: k is a radical of_i-thickness correction factor for the ith test piece; h_i-the conventional test thickness, mm, of the ith test piece; s_i-the detected thickness of the ith test piece, mm;

according to the formula

Calculating a uniform thickness correction factor

Step four, the dielectric constant empirical regression formula is as follows:

z＝7.01+0.299lnx-0.187y+0.004y² R²＝0.973

in the formula: z-predicted dielectric constant value; x-temperature (. degree. C.); y-maximum nominal particle size (mm) of different crushed stone aggregates;

substituting the obtained predicted dielectric constant value into a formulaV is the propagation speed of the radar wave in the ith test piece, and is mm/ns; s, detecting the thickness of a field asphalt composite gravel seal layer, which is mm; c, the propagation speed of the electromagnetic wave in vacuum is constant and is equal to about 300 mm/ns; delta t is the two-way travel time of the radar wave in the dielectric layer, ns;

and obtaining the predicted thickness of the asphalt composite gravel seal.

2. The method for detecting the thickness of the asphalt composite crushed stone seal based on the ground penetrating radar as claimed in claim 1, wherein the first step of manufacturing the indoor test piece of the asphalt composite crushed stone seal is as follows:

A₁: preparing 4-6 rut plate moulds with the thickness of 500mmX500mmX50mm, rubber pads with the thickness of 500mmX500mmX10mm, a wheel mill forming machine, an oven, a brush, an asphalt containing vessel, a small steel wheel, an electronic scale and other equipment;

A₂: weighing the required crushed stone masses with different particle sizes by using an electronic scale, putting the crushed stone masses into an oven, heating the crushed stone masses for 2 to 4 hours at the temperature of 160 to 180 ℃, then placing the asphalt into the oven, and heating the asphalt and the crushed stone masses for 2 hours at the temperature of 160 to 180 ℃;

A₃: coating diesel oil on all the rutting plate moulds, putting 500mmX500mm oil absorption paper, pouring the required asphalt amount on the rutting plate moulds according to the designed asphalt distribution amount, and putting the rutting plate moulds into a drying oven to keep the temperature at 160-180 ℃ for 30 minutes;

A₄: taking out the rutting plate mold, uniformly spreading the first layer of broken stone on the asphalt film, preliminarily compacting by using a small steel wheel, immediately coating asphalt on the surface and the periphery of the first layer of broken stone with a brush according to the designed asphalt spreading amount of the second layer, and putting the first layer of broken stone into an oven to heat for 30 minutes at the temperature of 160-180 ℃; taking out the rutting plate mold, uniformly spreading a second layer of broken stone on the first layer of broken stone, preliminarily compacting by using a small steel wheel, immediately coating asphalt on the surface and the periphery of the second layer of large-particle-size broken stone by using a brush according to the designed asphalt spreading amount of the second layer, and putting the second layer of broken stone into an oven again to keep the temperature at 160-180 ℃ for 30 minutes; … … straightUntil the last layer of broken stones is uniformly spread, and preliminarily compacting by using a small steel wheel;

A₅: spreading a release agent on the rubber pad, padding the rubber pad on a track plate die, and performing rolling molding by using a wheel rolling molding instrument.

3. The method for detecting the thickness of the asphalt composite crushed stone seal based on the ground penetrating radar as claimed in claim 1, wherein the conventional thickness detection method in the second step comprises the following specific steps:

B₁: selecting a position with a relatively flat surface in each test piece, and measuring the vertical distance h from the position to the edge of the rutting plate mold by using a measuring tape_i；

B₂: by the formula

H_i＝H-h_i

Wherein H_i-room thickness, mm, of the ith test piece; h, the inner height of the track plate mold;

the indoor thickness of each test piece was calculated.

4. The method for detecting the thickness of the asphalt composite crushed stone seal based on the ground penetrating radar as claimed in claim 1, wherein the ground penetrating radar detection method in the third step comprises the following specific steps:

C₁: directly measuring the thickness of the formed asphalt composite crushed stone seal layer on a test piece mold according to the operation specification of the ground penetrating radar;

C₂: obtaining the amplitude ratio of the passing test piece according to radar chart and formula

Wherein epsilon_ri-the dielectric constant of the ith specimen;-amplitude ratio;

calculating the dielectric constant of each test piece;

C₃: substituting the obtained dielectric constant into a formula

Wherein v is_i-the propagation speed of the radar wave in the ith test piece, mm/ns; s_i-detected thickness of the ith test piece, mm; c, the propagation speed of the electromagnetic wave in vacuum is constant and is equal to about 300 mm/ns; delta t is the two-way travel time of the radar wave in the dielectric layer, ns;

and calculating the thickness detected by the ground penetrating radar of each test piece.

5. The method for detecting the thickness of the asphalt composite crushed stone seal based on the ground penetrating radar as claimed in claim 1, wherein the thickness of the on-site asphalt composite crushed stone seal based on the thickness correction coefficient in the sixth step is calculated by the following formula:

in the formula: m is the corrected thickness of the on-site asphalt composite gravel seal layer, and is mm.

6. The method for detecting the thickness of the asphalt composite gravel seal based on the ground penetrating radar as claimed in claim 1, wherein the seven relative errors in the step are obtained by the following formula:

wherein, Delta S is the relative error between the corrected thickness of the on-site asphalt composite gravel seal and the predicted thickness.

7. The method for detecting the thickness of the asphalt composite gravel seal based on the ground penetrating radar as claimed in claim 1, wherein the remedy of the step eight is to additionally lay a fine-grained synchronous gravel seal.

Technical Field

The invention relates to the technical field of road construction detection, in particular to a method for detecting the thickness of an asphalt composite crushed stone seal layer based on a ground penetrating radar.

Background

In road engineering, the thickness of a road surface is closely related to the overall strength of the road. When the pavement is designed, the thickness of each layer is finally determined no matter the cement concrete pavement or the asphalt concrete pavement, and the overall strength and pavement performance of the pavement can be ensured only under the condition of ensuring the thickness. In addition to ensuring strength, tight control of the thickness of the various structural layers is a very important aspect. Therefore, it is important to detect the thickness of the road surface during road construction or completion acceptance.

The embedded and extruded structure formed by the asphalt composite macadam seal layer serving as the multilayer synchronous macadam seal layer can be used for additional paving, reconstruction and maintenance of urban roads and highways of different grades and can also be used for new construction of urban roads and highways of low grade, so that thickness detection of the asphalt composite macadam seal layer is very necessary, construction quality can be checked in time, and paving thickness of an asphalt surface layer can be adjusted according to the detected thickness.

The existing pavement thickness detection method mainly comprises a core drilling sampling method and a ground penetrating radar detection method, the traditional core drilling sampling method is convenient to operate and is visual and accurate, but can generate great damage to the pavement, if the pavement is not repaired and processed well, the pavement is likely to be changed into a road disease, meanwhile, as the sampling is random, great contingency is achieved, high-frequency detection cannot be carried out on the thickness of a structural layer, time and labor are wasted, and the efficiency is low. The ground penetrating radar nondestructive detection method is characterized in that a ground penetrating radar antenna sends pulse type high-frequency electromagnetic waves to the lower part of a road, the electromagnetic waves are reflected when the dielectric constant of a substance changes in the process of transmitting the electromagnetic waves to the lower part of the road, the electromagnetic waves reflected back to the road are received by a receiving antenna on the road and transmitted to a processor, the received reflected electromagnetic waves are analyzed by the processor, the characteristics (wave speed, amplitude and the like) of the reflected electromagnetic waves are analyzed, the thickness, compactness, defects and the like of each layer of the road can be obtained, and the ground penetrating radar has the characteristics of quickness, flexibility, accurate positioning, visual image, high efficiency and convenience in roadbed and road surface detection and cannot damage the road.

However, in the field test regulation of highway subgrade and pavement (JTG E60-2019), ground penetrating radar is still required to measure the thickness of the pavement, and the dielectric constant of the pavement material is still calibrated by using a drilling and coring method, so as to calculate the thickness of the pavement. This indicates that the damage to the pavement is still inevitable, and the dielectric constant of the pavement material is also changed due to the change of the material type, the compactness, the water content and the like, so that the uncertainty is obvious. Therefore, accidental errors caused by this method are difficult to accurately evaluate. Theoretically, the dielectric constants of all measuring points can be obtained through ground penetrating radar detection based on a reflection coefficient method, but in actual operation, many influence factors such as surface scattering, interface unevenness and the like exist, great variability exists, and relatively large errors are easy to generate, in actual engineering application, the ground penetrating radar can cause real-time changes of a measuring distance and an incident angle along with factors such as mechanical vibration and road surface fluctuation, so that a measuring result of the relative dielectric constant is obviously influenced, and errors of about +/-15% can be caused.

In addition, because the asphalt composite gravel seal is formed by spreading a plurality of layers of synchronous gravel seals, the particle size of the gravel is gradually reduced from bottom to top, if a core drilling sampling method is adopted to measure the thickness of the asphalt composite gravel seal, in the core sampling process, if the bonding force between the gravel and the high-elasticity asphalt is not enough, a large amount of threshing phenomena can be caused, the measurement precision is influenced, a plurality of points are required to be taken for measurement, the errors are superposed, and the pavement repair is troublesome.

Aiming at the problems, the thickness of the test piece is calculated by combining a ground penetrating radar method and an indoor conventional thickness detection method to obtain a relevant thickness correction coefficient, and the thickness error of the asphalt composite gravel seal calculated based on a reflection coefficient method is reduced or even eliminated according to the correction coefficient each time.

Disclosure of Invention

The invention aims to solve the problem that the thickness of the existing asphalt composite crushed stone seal is difficult to detect, and provides a method for detecting the thickness of the asphalt composite crushed stone seal based on a ground penetrating radar. In order to achieve the purpose, the invention is implemented according to the following technical scheme:

the invention relates to a method for detecting the thickness of an asphalt composite macadam seal coat based on a ground penetrating radar, which comprises the following steps:

firstly, manufacturing 4-6 asphalt composite crushed stone seal layer indoor test pieces;

step two, measuring the thickness of the manufactured test piece by using a conventional thickness detection method;

thirdly, measuring the thickness of the manufactured test piece by using a ground penetrating radar-based detection method;

step four, based on the step two and the step three, carrying out normalization processing on the data, and obtaining a corresponding thickness correction coefficient through a formula;

step five, based on the steps, providing an empirical regression formula of the dielectric constant, and predicting the thickness of the seal layer before construction;

step six, after the construction of the asphalt composite crushed stone seal is finished, detecting the thickness of the on-site asphalt composite crushed stone seal by using a ground penetrating radar detection method, and correcting by using a corresponding correction coefficient;

step seven, comparing the predicted thickness obtained in the step six with the actually measured thickness obtained in the step seven, calculating the relative error of the predicted thickness and checking the accuracy of the actually measured thickness;

and step eight, if the relative error is less than-2%, taking remedial measures.

Preferably, the formula of the thickness correction coefficient in the third step is

In the formula: k is a radical of_i-thickness correction factor for the ith test piece; h_i-the conventional test thickness, mm, of the ith test piece; s_i-the detected thickness of the ith test piece, mm;

according to the formula

Calculating a uniform thickness correction factor

Preferably, the empirical regression formula of the dielectric constant in the step four is as follows:

z＝7.01+0.299lnx-0.187y+0.004y² R²＝0.973

in the formula: z-predicted dielectric constant value; x-temperature (. degree. C.); y-maximum nominal grain size (mm) of different crushed stone aggregates.

Substituting the obtained predicted dielectric constant value into a formulaV is the propagation speed of the radar wave in the ith test piece, and is mm/ns; s, detecting the thickness of a field asphalt composite gravel seal layer, which is mm; c, the propagation speed of the electromagnetic wave in vacuum is constant and is equal to about 300 mm/ns; delta t is the two-way travel time of the radar wave in the dielectric layer, ns;

and obtaining the predicted thickness of the asphalt composite gravel seal.

Preferably, the first step of manufacturing the indoor test piece of the asphalt composite gravel seal comprises the following steps:

A₁: preparing 4-6 rut plate moulds with the thickness of 500mmX500mmX50mm, rubber pads with the thickness of 500mmX500mmX10mm, a wheel mill forming machine, an oven, a brush, an asphalt containing vessel, a small steel wheel, an electronic scale and other equipment;

A₂: weighing the required crushed stone masses with different particle sizes by using an electronic scale, putting the crushed stone masses into an oven, heating the crushed stone masses for 2 to 4 hours at the temperature of 160 to 180 ℃, then placing the asphalt into the oven, and heating the asphalt and the crushed stone masses for 2 hours at the temperature of 160 to 180 ℃;

A₃: coating diesel oil on all the rutting plate moulds, putting 500mmX500mm oil absorption paper, pouring the required asphalt amount on the rutting plate moulds according to the designed asphalt distribution amount, and putting the rutting plate moulds into a drying oven to keep the temperature at 160-180 ℃ for 30 minutes;

A₄: taking out the rutting plate mold, uniformly spreading the first layer of broken stone on the asphalt film, preliminarily compacting by using a small steel wheel, immediately coating asphalt on the surface and the periphery of the first layer of broken stone with a brush according to the designed asphalt spreading amount of the second layer, and putting the first layer of broken stone into an oven to heat for 30 minutes at the temperature of 160-180 ℃; taking out the rutting plate mold, uniformly spreading a second layer of broken stone on the first layer of broken stone, preliminarily compacting by using a small steel wheel, immediately coating asphalt on the surface and the periphery of the second layer of large-particle-size broken stone by using a brush according to the designed asphalt spreading amount of the second layer, and putting the second layer of broken stone into an oven again to keep the temperature at 160-180 ℃ for 30 minutes; … … until the last layer of broken stone is spread evenly, and the small steel wheel is used for preliminary compaction;

A₅: spreading a release agent on the rubber pad, padding the rubber pad on a track plate die, and performing rolling molding by using a wheel rolling molding instrument.

Preferably, the step two conventional thickness detection method comprises the following specific steps:

B₁: selecting a position with a relatively flat surface in each test piece, and measuring the position to be vertical to the edge of the rutting plate mold by using a measuring tapeDistance h_i；

B₂: by the formula

H_i＝H-h_i

Wherein H_i-room thickness, mm, of the ith test piece; h, the inner height of the track plate mold;

the indoor thickness of each test piece was calculated.

Preferably, the ground penetrating radar detection method of the third step comprises the following specific steps:

C₁: directly measuring the thickness of the formed asphalt composite crushed stone seal layer on a test piece mold according to the operation specification of the ground penetrating radar;

C₂: obtaining the amplitude ratio of the passing test piece according to radar chart and formula

Wherein epsilon_ri-the dielectric constant of the ith specimen;-amplitude ratio;

calculating the dielectric constant of each test piece;

C₃: substituting the obtained dielectric constant into a formula

Wherein v is_i-the propagation speed of the radar wave in the ith test piece, mm/ns; s_i-detected thickness of the ith test piece, mm; c, the propagation speed of the electromagnetic wave in vacuum is constant and is equal to about 300 mm/ns; delta t is the two-way travel time of the radar wave in the dielectric layer, ns;

and calculating the thickness detected by the ground penetrating radar of each test piece.

Preferably, the thickness of the on-site asphalt composite gravel seal based on the thickness correction coefficient in the step six is calculated by the following formula:

in the formula: m is the corrected thickness of the on-site asphalt composite gravel seal layer, and is mm.

Preferably, the step seven relative error is obtained by the following formula:

wherein, Delta S is the relative error between the corrected thickness of the on-site asphalt composite gravel seal and the predicted thickness.

Preferably, the remedy measure in the step eight is to additionally lay a fine-grain synchronous gravel seal.

The beneficial effects of the invention are:

(1) the invention draws the advantages of the indoor conventional thickness detection method and the ground penetrating radar method, provides the thickness correction coefficient, reduces or even eliminates the pavement thickness error obtained by the ground penetrating radar detection method according to the correction coefficient each time, and greatly improves the detection precision of the traditional ground penetrating radar detection method;

(2) the invention determines the correction coefficient of the dielectric constant through an indoor experiment, does not need on-site core drilling sampling to calibrate the dielectric constant, achieves the aim of nondestructive testing, avoids the problem of repairing after core drilling, and eliminates the possibility of diseases caused by core drilling;

(3) the invention carries out grading and temperature nonlinear fitting on the dielectric constant through test data, provides a dielectric constant empirical regression formula, can better predict the thickness of the asphalt composite crushed stone seal, can provide reference for selection of crushed stone particle size in turn according to construction design thickness, and can also control the thickness of a subsequent asphalt concrete surface layer according to the predicted thickness, thereby avoiding the problem of blindly increasing the thickness for reaching the quality standard, reducing resource waste, reducing construction cost, providing a theoretical thickness for actual measurement of field construction, guiding the construction of the asphalt composite crushed stone seal and ensuring construction quality;

(4) the invention provides an indoor forming method of an asphalt composite gravel seal, which is characterized in that a hydraulic wheel-rolling test forming machine is used for forming the asphalt composite gravel seal, a small steel wheel is used for preliminary flattening after each gravel seal is paved, then a rubber pad is laid, and a wheel-rolling instrument is used for rolling, so that the compaction operation of a steel wheel road roller and a rubber wheel road roller in site construction is simulated, the effect close to site construction is achieved, and the accuracy of a thickness correction coefficient is improved.

The invention reduces or even eliminates the pavement thickness error obtained by a ground penetrating radar detection method, greatly improves the detection precision of the traditional ground penetrating radar detection method, achieves the aim of nondestructive detection, avoids the problem of repairing after core drilling, eliminates the possibility of diseases caused by core drilling, guides the construction of the asphalt composite crushed stone seal, ensures the construction quality and improves the precision of the thickness correction coefficient.

Drawings

FIG. 1 is a flow chart of a thickness detection method.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

Example one

Referring to fig. 1, a flow chart of a thickness detection method according to the present invention includes the following steps:

step one, 5 indoor test pieces of the asphalt composite gravel seal are manufactured, and the specific manufacturing process is as follows:

A₁: preparing 5 rut plate moulds with the thickness of 500mmX500mmX50mm, rubber pads with the thickness of 500mmX500mmX10mm, a wheel mill forming machine, an oven, a brush, an asphalt containing vessel, a small steel wheel, an electronic scale and other equipment;

A₂: weighing the required crushed stones with different particle sizes by using an electronic scale, putting the crushed stones into an oven, heating the crushed stones for 2 hours at the temperature of 180 ℃, then putting the asphalt into the oven, and heating the asphalt and the crushed stones for 2 hours at the temperature of 180 ℃;

A₃: coating diesel oil on all the rutting plate moulds, putting 500mmX500mm oil absorption paper, pouring the required asphalt amount on the rutting plate moulds according to the designed asphalt distribution amount, and putting the rutting plate moulds into an oven to keep the temperature at 180 ℃ for 30 minutes;

A₄: taking out the rutting plate mold, uniformly spreading the first layer of broken stone on the asphalt film, preliminarily compacting by using a small steel wheel, immediately coating asphalt on the surface and the periphery of the first layer of broken stone with a brush according to the designed asphalt spreading amount of the second layer, and putting the first layer of broken stone into an oven to heat for 30 minutes at the temperature of 180 ℃; taking out the rutting plate mold, uniformly spreading a second layer of broken stone on the first layer of broken stone, preliminarily compacting by using a small steel wheel, immediately coating asphalt on the surface and the periphery of the second layer of large-particle-size broken stone by using a brush according to the designed asphalt spreading amount of the second layer, and putting the second layer of broken stone into an oven again to keep the temperature at 180 ℃ for 30 minutes; taking out the rutting plate mold, uniformly spreading a third layer of broken stone on a second layer of broken stone, preliminarily compacting by using a small steel wheel, immediately coating asphalt on the surface and the periphery of the second layer of broken stone with a brush according to the designed asphalt spreading amount of the third layer, and putting the second layer of broken stone into an oven to preserve heat for 30 minutes at the temperature of 180 ℃; taking out the rut plate mold, uniformly spreading the fourth layer of broken stone on the third layer of broken stone, and preliminarily compacting by using a small steel wheel;

A₅: smearing a release agent on the rubber pad, padding the rubber pad on a track plate die, and performing rolling forming by using a wheel rolling forming instrument;

step two, using a conventional thickness detection method to measure the thickness of the manufactured test piece, wherein the specific detection process is as follows:

B₁: selecting a position with a relatively flat surface in each test piece, and measuring the vertical distance h from the position to the edge of the rutting plate mold by using a measuring tape_i；

B₂: by the formula

H_i＝H-h_i

Wherein H_i-room thickness, mm, of the ith test piece; h, the inner height of the track plate mold;

calculating the indoor thickness of each test piece;

step three, performing thickness measurement on the manufactured test piece by using a ground penetrating radar-based detection method, wherein the specific detection flow is as follows:

C₁: directly measuring the thickness of the formed asphalt composite crushed stone seal layer on a test piece mold according to the operation specification of the ground penetrating radar;

C₂: obtaining the amplitude ratio of the passing test piece according to radar chart and formula

Wherein epsilon_ri-the dielectric constant of the ith specimen;-amplitude ratio;

calculating the dielectric constant of each test piece;

C₃: substituting the obtained dielectric constant into a formula

Wherein v is_i-the propagation speed of the radar wave in the ith test piece, mm/ns; s_i-detected thickness of the ith test piece, mm; c, the propagation speed of the electromagnetic wave in vacuum is constant and is equal to about 300 mm/ns; delta t is the two-way travel time of the radar wave in the dielectric layer, ns;

calculating the thickness detected by the ground penetrating radar of each test piece;

step four, based on the step two and the step three, normalizing the data through a formula

In the formula: k is a radical of_i-thickness correction factor for the ith test piece; h_i-the conventional test thickness, mm, of the ith test piece; s_i-the detected thickness of the ith test piece, mm;-unifying the thickness correction factor;

obtaining a uniform thickness correction coefficient;

and step five, based on the steps, providing a dielectric constant empirical regression formula, predicting the seal layer thickness before construction, wherein the dielectric constant empirical regression formula is as follows:

z＝7.01+0.299lnx-0.187y+0.004y² R²＝0.973

wherein z is the predicted dielectric constant value; x-temperature (. degree. C.); y-maximum nominal grain size (mm) of different crushed stone aggregates.

Substituting the obtained predicted dielectric constant value into a formulaV is the propagation speed of the radar wave in the ith test piece, and is mm/ns; s, predicting the thickness of the on-site asphalt composite gravel seal layer in mm; c, the propagation speed of the electromagnetic wave in vacuum is constant and is equal to about 300 mm/ns; delta t is the two-way travel time of the radar wave in the dielectric layer, ns;

obtaining the predicted thickness of the asphalt composite gravel seal;

step six, after the construction of the asphalt composite crushed stone seal is finished, detecting the thickness of the on-site asphalt composite crushed stone seal by using a ground penetrating radar detection method, correcting by using a corresponding correction coefficient according to a formula

In the formula: m is the corrected thickness of the on-site asphalt composite gravel seal layer, which is mm;

and calculating to obtain the corrected thickness of the on-site asphalt composite gravel seal.

Step seven, comparing the predicted thickness obtained in the step six with the actually measured thickness obtained in the step seven, calculating a relative error of the predicted thickness and checking the accuracy of the actually measured thickness, wherein the relative error calculation formula is as follows:

wherein, Delta S is the relative error between the corrected thickness of the on-site asphalt composite gravel seal and the predicted thickness;

and step eight, if the relative error is less than-2%, additionally laying a fine-grain synchronous gravel seal layer.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.