A device for detecting the buried depth of highway guardrail columns based on ground penetrating radar

Abstract

The present invention provides a device for detecting the buried depth of highway guardrail columns based on ground penetrating radar, which relates to the technical field of traffic safety facility detection. The device includes a ground penetrating radar and a data processing device. The ground penetrating radar is placed on the road surface. While the ground penetrating radar moves along a direction parallel to the driving direction and at a preset distance from the target column, the diffraction wave at the bottom of the target column is detected laterally by using the beam width of the radar antenna. According to the reflected wave at the layer interface where the buried depth of the target column is located and the diffraction wave at the diffraction point, combined with the number of strata, the buried depth at the bottom of the target column is calculated. It can not only perform mobile detection on the road surface, greatly improving the detection efficiency, but also achieve high-accuracy and high-resolution target detection, meeting the requirements of engineering detection.

Description

Technical Field

[0001] The present invention relates to the technical field of traffic safety facility detection, and particularly relates to a detection device for the buried depth of highway guardrail columns based on ground penetrating radar. Background Art

[0002] As the main body to bear the impact force of vehicles running off the road, whether the highway guardrail columns have sufficient buried depth according to the design requirements will directly affect their protection ability for vehicles, which is an extremely important indicator. Therefore, it is very necessary to detect the buried depth at the bottom of the columns. The traditional method is to pull out the columns on site, that is, to detect after pulling out the columns. Although this method has the highest accuracy, it is laborious and time-consuming. Especially, it is easy to damage the integrity of the slope and roadbed. After pulling out the columns, the roadbed needs to be rammed again before the columns can be driven in again. Therefore, the on-site column pulling method cannot be used as a daily detection means. So, the engineering community is eagerly looking forward to effective and reliable non-destructive testing technologies and equipment.

[0003] The current non-destructive testing methods can generally be divided into three categories: (1) electromagnetic induction method; (2) ultrasonic method; (3) impact elastic wave. However, the efficiency of these methods is very low, and the detection accuracy cannot be guaranteed. Therefore, the present invention provides a detection device for the buried depth of highway guardrail columns based on ground penetrating radar, which can perform mobile detection on the road surface, greatly improving the detection efficiency. Summary of the Invention

[0004] The purpose of the present invention is to provide a detection device for the buried depth of highway guardrail columns based on ground penetrating radar. When the ground penetrating radar is placed on the road surface and moves along a direction parallel to the driving direction and at a preset distance from the target column, the ground penetrating radar uses the beam width of the radar antenna to perform side detection on the diffracted wave at the bottom of the target column. According to the reflected wave at the interface layer where the buried depth of the target column is located and the diffracted wave at the diffraction point, combined with the number of strata, the buried depth at the bottom of the target column is calculated. It can not only perform mobile detection on the road surface, greatly improving the detection efficiency, but also achieve high-accuracy and high-resolution target detection, meeting the requirements of engineering detection.

[0005] To solve the above technical problems, the present invention adopts the following solutions:

[0006] A detection device for the buried depth of highway guardrail columns based on ground penetrating radar includes a ground penetrating radar and a data processing device. The ground penetrating radar is placed on the road surface. When the ground penetrating radar moves along a direction parallel to the driving direction and at a preset distance from the target column, the ground penetrating radar uses the beam width of the radar antenna to perform side detection on the target column; the data processing device is used to analyze and process the radar wave data collected by the ground penetrating radar.

[0007] Further, when the ground penetrating radar performs side detection on the target column using the beam width of the radar antenna, when the diameter of the target column is less than the wavelength, a diffracted wave is generated.

[0008] Further, the side detection refers to detecting the target column deviating from directly below the radar antenna through the beam width of the radar antenna to achieve side detection of the target column.

[0009] Further, the radar antenna adopts ground contact detection or inclined detection. When performing ground contact detection, the radar antenna is in close contact with the road surface; when performing inclined detection, the radar antenna is equipped with a wedge-shaped structure device, and an included angle is generated between the wedge-shaped structure device and the road surface to change the beam incident angle.

[0010] Further, the analysis and processing process of the data processing device is as follows:

[0011] S1. Obtain the radar wave data of the ground penetrating radar in real time, detect the radar wave data. If the reflected wave of the layer interface where the buried depth of the target column is located and the diffracted waves of each diffracted point are detected, obtain the horizontal distance between the current ground penetrating radar and the target column, and go to step S2;

[0012] S2. Judge the layered medium for the reflected wave of the layer interface where the buried depth of the target column is located, and obtain the number of geological layers of the layer interface where the buried depth of the target column is located according to the judgment result of the layered medium;

[0013] S3. According to the horizontal distance between the current ground penetrating radar and the target column, the number of geological layers of the layer interface where the buried depth of the target column is located, and the diffracted waves of each diffracted point, calculate the buried depth of the bottom of the target column based on the ray path of the radar wave.

[0014] Further, the following steps are included in step S3:

[0015] S31. Obtain the number of geological layers of at least one layer interface where the buried depth of the target column is located;

[0016] S32. Calculate the layer velocity of each geological layer and the arrival time of the radar wave reaching the geological layer according to the number of geological layers of the layer interface where the buried depth of the target column is located;

[0017] S33. Calculate the buried depth of the bottom of the target column based on the layer velocity of the geological layer, the arrival time of the radar wave reaching the geological layer, the horizontal distance between the current ground penetrating radar and the target column, and the diffracted waves of each diffracted point according to the ray path of the radar wave.

[0018] Further, in S3, the process of calculating the layer velocity of each geological layer and the arrival time of the radar wave reaching the geological layer according to the number of geological layers of the layer interface where the buried depth of the target column is located is specifically as follows:

[0019] According to the order of the number of geological layers at the interface where the target column's buried depth is located, the velocities of the radar waves reaching the number of geological layers are successively fitted to obtain the layer velocities of the geological layers. At the same time, based on the layer velocities of the geological layers, the time for the radar waves to reach the number of geological layers is calculated to obtain the arrival time of the radar waves at the number of geological layers.

[0020] Further, in S31, the number of geological layers at the interface where at least one target column's buried depth is located is obtained. When the number of geological layers at the interface where one target column's buried depth is located is obtained, the diffracted waves of each detected diffracted point are the diffracted waves at the bottom of the target column; when the number of geological layers at the interface where multiple target columns' buried depths are located is obtained, the diffracted waves of each detected diffracted point include the diffracted waves at the intersections of multiple target columns and the interface where the target columns' buried depths are located, and the diffracted waves at the bottom of the target columns.

[0021] Further, the process of calculating the buried depth at the bottom of the target column in step S33 is as follows:

[0022] When the number of geological layers at the interface where one target column's buried depth is located is obtained, the shortest time of the diffracted wave at the bottom of the column is obtained based on the diffracted wave at the bottom of the target column. Then, based on the layer velocity of this geological layer, the shortest time of the diffracted wave at the bottom of the column, and the horizontal distance between the ground-penetrating radar and the target column, according to the radar wave ray path, the buried depth at the bottom of the target column is calculated.

[0023] When the number of geological layers at the interface where multiple target columns' buried depths are located is obtained, the shortest time of the diffracted wave at the bottom of the column is obtained based on the diffracted wave at the bottom of the target column, and the incident angle of the radar wave reaching each layer interface is calculated according to the diffracted waves at the intersections of multiple target columns and the interface where the target columns' buried depths are located to obtain the incident angles of the radar wave at different numbers of geological layers. According to the layer velocities of multiple geological layers, the arrival time of the radar wave at the number of geological layers, the shortest time of the diffracted wave at the bottom of the column, the horizontal distance between the ground-penetrating radar and the target column, and the incident angles of the radar wave at different numbers of geological layers, according to the radar wave ray path, the buried depth at the bottom of the target column is calculated.

[0024] Advantages of the present invention:

[0025] The present invention provides a device for detecting the buried depth of highway guardrail columns based on ground penetrating radar. By using an existing ground penetrating radar for detection, the ground penetrating radar is placed on the road surface. While moving along a direction parallel to the driving direction and at a preset distance from the target column, the diffraction wave at the bottom of the target column is detected laterally by using the beam width of the radar antenna. Through lateral detection, not only the reflection wave of the layer interface directly below can be detected, but also the diffraction wave at the bottom of the lateral target column can be detected. By analyzing and processing the reflection wave and the diffraction wave, the buried depth of the bottom of the target column can be calculated. The device for detecting the buried depth of highway guardrail columns in the present invention performs mobile detection on the road surface, overcoming the disadvantage of low efficiency of the traditional method. Moreover, while meeting the non-contact detection of the buried depth of highway columns, different frequency radar antennas can also be used to achieve detection with different depths and resolutions, realizing fast and high-resolution radar detection and meeting the requirements of engineering detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a plan view of the road surface when the ground penetrating radar performs lateral detection on the column in Embodiment 1 of the present invention;

[0027] Figure 2 It is a schematic diagram of changing the beam width when the ground penetrating radar performs lateral detection on the column in Embodiment 1 of the present invention;

[0028] Figure 3 It is a schematic diagram of the beam width when the ground penetrating radar that forms an angle with the road surface performs lateral detection on the column in Embodiment 1 of the present invention;

[0029] Figure 4 It is a flow chart of the analysis and processing process in Embodiment 1 of the present invention;

[0030] Figure 5 It is a schematic cross-sectional view of the principle of the ground penetrating radar performing lateral detection on the target column in the case of a single layer of the buried depth of the target column in Embodiment 1 of the present invention;

[0031] Figure 6 It is a schematic cross-sectional view of the principle of the ground penetrating radar performing lateral detection on the target column in the case of two layers of the buried depth of the target column in Embodiment 1 of the present invention;

[0032] Figure 7 It is a schematic cross-sectional view of the principle of the ground penetrating radar performing lateral detection on the target column in the case of three layers of the buried depth of the target column in Embodiment 1 of the present invention;

[0033] Figure 8 It is a vertical section view of the three-dimensional model for simulating the detection of the bottom of the target column in Embodiment 1 of the present invention;

[0034] Figure 9This is a schematic diagram of the radar profile obtained by ground penetrating radar when simulating the buried depth of the target column in two layers in Embodiment 1 of the present invention. Detailed implementation manners

[0035] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way restrictive of the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0036] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and values set forth in these embodiments do not limit the scope of the present invention.

[0037] At the same time, it should be understood that for the sake of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationship.

[0038] In addition, for the sake of clarity and conciseness, the descriptions of well-known structures, functions and configurations may be omitted. Those of ordinary skill in the art will recognize that various changes and modifications can be made to the examples described herein without departing from the spirit and scope of the present disclosure.

[0039] For technologies, methods and devices known to those of ordinary skill in the relevant fields, detailed discussions may not be made, but where appropriate, the technologies, methods and devices should be regarded as part of the authorization specification.

[0040] In all the examples shown and discussed here, any specific value should be construed as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0041] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments:

[0042] Embodiment 1

[0043] In this embodiment, a device for detecting the buried depth of highway guardrail columns based on ground penetrating radar is provided, including a ground penetrating radar and a data processing device, such as Figure 1As shown, a number of columns are arranged on the road surface of the highway. The ground penetrating radar is placed on the road surface of the highway, and the ground penetrating radar is moved for detection along its moving detection line for ground penetrating radar. The moving detection line for ground penetrating radar moves along a direction parallel to the driving direction and at a preset distance from the target column. And while moving, radar wave data can be collected; the data processing device is used to analyze and process the radar wave data collected by the ground penetrating radar, and the burial depth at the bottom of the target column can be obtained through analysis and processing.

[0044] Among them, the data processing device includes a Windows system computer with a graphics card and data processing software. The data processing software is developed based on MATLAB and has functions such as import, processing, result display, and result export of radar data.

[0045] When the ground penetrating radar conducts radar wave detection, the radiation beam of the radar antenna has a width. Therefore, the ground penetrating radar can not only detect the target directly below the radar antenna, but also detect targets within a certain range deviating from directly below. Then, the present invention uses the beam width of the radar antenna to conduct side detection on the target column, as Figure 2 As shown, the side detection mainly refers to detecting the target column deviating from directly below the radar antenna through the beam width of the radar antenna to achieve side detection of the target column.

[0046] When the ground penetrating radar conducts radar wave detection, electromagnetic scattering will occur when the radar wave encounters a target. When the target is much larger than the wavelength, reflection occurs, and reflection is a special case of scattering; when the target is smaller than the wavelength, diffraction occurs. Therefore, when the ground penetrating radar uses the beam width of the radar antenna to conduct side detection on the target column, when the diameter of the target column is smaller than the wavelength, a diffracted wave is generated. And when the ground penetrating radar uses the beam width of the radar antenna to conduct side detection on the target column, the radar wave is reflected when it encounters the target layer interface and diffracted when it encounters the intersection point of the target column and the layer interface where the burial depth of the target column is located. This intersection point is the diffraction point.

[0047] Therefore, when using the beam width of the radar antenna to conduct side detection on the target column, not only can the diffracted wave at the bottom of the target column be detected, but also the reflected wave of the layer interface directly below can be detected. By analyzing and processing the reflected wave of the layer interface, the structural characteristics of the formation can be obtained, and the number of geological layers of the layer interface where the burial depth of the target column is located can be analyzed and processed.

[0048] During the process of the data processing device analyzing and processing the radar wave data collected by the ground penetrating radar, considering the layered media in the number of geological layers of the layer interface where different target columns are buried, multiple layer velocities of the geological layers are obtained by means of velocity fitting, and then, by means of the ray relationship, the burial depth at the bottom of the target column can be calculated, and the burial depth at the bottom of the target column can be accurately obtained.

[0049] In addition, considering the complexity of the underground situation, when detection is sometimes difficult, an auxiliary device can be used to appropriately change the beam direction and increase the radiation energy of the radar antenna towards the bottom of the target column. In one embodiment, as Figure 3 shown, the radar antenna uses inclined detection. A wedge-shaped structure is mounted on the radar antenna, creating a certain angle between the radar antenna and the road surface through the wedge-shaped structure to change the beam incident angle.

[0050] When the side detection of the target column is performed using the beam width of the radar antenna, the ground-penetrating radar can collect radar wave data in real time and upload the radar wave data to the data processing device, enabling the data processing device to analyze and process the radar wave data. As Figure 4 shown, the specific process is as follows:

[0051] S1. Obtain the radar wave data of the ground-penetrating radar in real time, detect the radar wave data. If the reflected wave of the layer interface where the buried depth of the target column is located and the diffracted waves of each diffracted point are detected, obtain the horizontal distance between the current ground-penetrating radar and the target column, and proceed to step S2;

[0052] Among them, the horizontal distance between the ground-penetrating radar and the target column is directly measured with a tape measure;

[0053] S2. Judge the layered medium for the reflected wave of the layer interface where the buried depth of the target column is located, and obtain the number of geological layers of the layer interface where the buried depth of the target column is located according to the judgment result of the layered medium;

[0054] S3. According to the horizontal distance between the current ground-penetrating radar and the target column, the number of geological layers of the layer interface where the buried depth of the target column is located, and the diffracted waves of each diffracted point, calculate the buried depth of the bottom of the target column based on the ray path of the radar wave.

[0055] Preferably, the step S3 includes the following steps:

[0056] S31. Obtain the number of geological layers of at least one layer interface where the buried depth of the target column is located;

[0057] S32. Calculate the layer velocity of each geological layer number and the arrival time of the radar wave reaching the geological layer number according to the number of geological layers of the layer interface where the buried depth of the target column is located;

[0058] S33. Calculate the buried depth of the bottom of the target column based on the layer velocity of the geological layer number, the arrival time of the radar wave reaching the geological layer number, the horizontal distance between the current ground-penetrating radar and the target column, and the diffracted waves of each diffracted point, according to the ray path of the radar wave.

[0059] Since the structural characteristics of the formation consist of the number of formation layers arranged in order from top to bottom, when the ground penetrating radar uses the beam width of the radar antenna to perform side detection on the target column, the radar wave can reach multiple formation layers in sequence from top to bottom, and corresponding reflected waves or diffracted waves are generated at the layer interfaces corresponding to the multiple formation layers.

[0060] Therefore, when the ground penetrating radar uses the beam width of the radar antenna to perform side detection on the target column, at least the number of formation layers at the layer interface where the buried depth of the target column is located can be obtained. Moreover, since the different numbers of formation layers will affect the radar wave ray path, the radar wave data collected by the ground penetrating radar is different. Specifically, when obtaining the number of formation layers at the layer interface where the buried depth of a target column is located, diffracted waves at the bottom of the target column can be detected in the radar wave data; when obtaining the numbers of formation layers at the layer interfaces where the buried depths of multiple target columns are located, diffracted waves at the intersections of the multiple target columns and the layer interfaces where the buried depths of the target columns are located and diffracted waves at the bottoms of the target columns can be detected in the radar wave data.

[0061] Based on the radar wave data collected from the above different numbers of formation layers, the analysis and processing methods of the data processing device also vary. According to different numbers of formation layers, the data analysis and processing methods are divided into the following two methods:

[0062] The first data analysis and processing method: When obtaining the number of formation layers at the layer interface where the buried depth of a target column is located, the shortest time of the diffracted wave at the bottom of the column is obtained according to the diffracted wave at the bottom of the target column, and then based on the layer velocity of this formation layer, the shortest time of the diffracted wave at the bottom of the column, and the horizontal distance between the ground penetrating radar and the target column, according to the radar wave ray path, the buried depth of the bottom of the target column is calculated;

[0063] The second data analysis and processing method: When obtaining the numbers of formation layers at the layer interfaces where the buried depths of multiple target columns are located, the shortest time of the diffracted wave at the bottom of the column is obtained according to the diffracted wave at the bottom of the target column, and the incident angle of the radar wave reaching each layer interface is calculated according to the diffracted waves at the intersections of the multiple target columns and the layer interfaces where the buried depths of the target columns are located, to obtain the incident angles of the radar wave at different formation layers. According to the layer velocities of the multiple formation layers, the arrival time of the radar wave reaching the formation layers, the shortest time of the diffracted wave at the bottom of the column, the horizontal distance between the ground penetrating radar and the target column, and the incident angles of the radar wave at different formation layers, according to the radar wave ray path, the buried depth of the bottom of the target column is calculated.

[0064] Based on the above two data analysis and processing methods, the specific processes of analyzing and processing the radar wave data when obtaining the number of formation layers at the layer interface where the buried depth of one target column is located, the numbers of formation layers at the layer interfaces where the buried depths of two target columns are located, and the numbers of formation layers at the layer interfaces where the buried depths of three target columns are located are described.

[0065] AsFigure 5 As shown, when obtaining the number of geological layers of the layer interface where the buried depth of a target column is located, the layered medium is a single-layer medium, and the layer interface where the buried depth of the target column is located is a single layer. That is, the buried depth of the target column is in geological layer number 1. The ground penetrating radar can only receive the direct wave and the diffracted wave at the bottom of the target column. The single-trace waveform closest to the target column is on the Figure 5 right side of. As the ground penetrating radar moves along the moving survey line of the ground penetrating radar, the isochrones composed of the direct waves are linearly distributed, and the diffracted waves of the target column show a hyperbolic distribution. At this time, the buried depth h of the bottom of the target column is: ;

[0066] where t is the shortest time of the diffracted wave at the bottom of the target column; v1 is the layer velocity of geological layer number 1; D is the horizontal distance between the ground penetrating radar and the target column. Among them, v1 can be obtained by the method of velocity fitting, and can also be obtained according to prior knowledge in the case where the diffracted wave is not clear.

[0067] As Figure 6 shown, when obtaining the number of geological layers of the layer interfaces where the buried depths of two target columns are located, the layered medium is a two-layer medium, and the layer interfaces where the buried depths of the target columns are located are two layers. That is, the buried depths of the target columns are successively geological layer number 1 and geological layer number 2 from top to bottom. In addition to the direct wave, the ground penetrating radar can also receive the diffracted wave at the intersection of the target column and the layer interface where the buried depth of the target column is located, the diffracted wave at the bottom of the target column, and the reflected wave of the layer interface where the buried depth of the target column is located. The single-trace waveform closest to the target column is on the Figure 6 right side of. As the ground penetrating radar moves along the moving survey line of the ground penetrating radar, the isochrones composed of the direct wave and the reflected waves of geological layer number 1 and geological layer number 2 are linearly distributed, and each diffracted wave shows a hyperbolic distribution. At this time, the buried depth h of the bottom of the target column is:

[0068] ;

[0069] ;

[0070] where , h1 is the layer thickness of geological layer number 1, h2 is the buried depth of the target column in geological layer number 2, t is the shortest time of the diffracted wave at the bottom of the target column, t1 is the reflection time of the reflected wave of geological layer number 1, v1 is the layer velocity of geological layer number 1, v2 is the layer velocity of geological layer number 1, D is the horizontal distance between the ground penetrating radar and the target column, is the incident angle of the radar wave in geological layer number 1, is the incident angle of the radar wave in geological layer number 2.

[0071] As Figure 7As shown in the figure, when the number of strata at the layer interfaces where the buried depths of the three target columns are obtained, the layered medium is a three-layer medium, and the layer interfaces where the buried depths of the target columns are located are three layers, that is, the buried depths of the target columns from top to bottom are stratum number 1, stratum number 2, and stratum number 3. At this time, the ground penetrating radar is similar to that when the number of strata at the layer interfaces where the buried depths of the two target columns are obtained. In addition to receiving the direct wave, it can also receive the diffracted wave at the intersection of the target column and the layer interface where the buried depth of the target column is located, the diffracted wave at the bottom of the target column, and the reflected wave of the layer interface where the buried depth of the target column is located. The single-trace waveform closest to the target column is Figure 7 on the right side of. As the ground penetrating radar moves along the moving survey line of the ground penetrating radar, the isochrones composed of the direct wave and the reflected waves of stratum number 1, stratum number 2, and stratum number 3 are linearly distributed, and each diffracted wave presents a hyperbolic distribution. At this time, the way the data processing device analyzes and processes the radar wave data is also similar to the way of analyzing and processing the radar wave data when the number of strata at the layer interfaces where the buried depths of the two target columns are obtained, and the buried depth h of the bottom of the target column can be given as:

[0072] ;

[0073] ;

[0074] ;

[0075] where, ;

[0076] h1 is the thickness of stratum number 1, h2 is the thickness of stratum number 2, h3 is the buried depth of the target column in stratum number 2, t is the shortest time of the diffracted wave at the bottom of the target column, t1 is the reflection time of the reflected wave of stratum number 1, t2 is the reflection time of the reflected wave of stratum number 2, v1 is the layer velocity of stratum number 1, v2 is the layer velocity of stratum number 1, v3 is the layer velocity of stratum number 1, D is the horizontal distance between the ground penetrating radar and the target column, is the incident angle of the radar wave in stratum number 1, is the refraction angle / incident angle of the radar wave in stratum number 2, is the refraction angle of the radar wave in stratum number 3.

[0077] In summary, the present invention mainly proposes two data analysis and processing methods based on the ground penetrating radar and the data processing device. One is the data analysis and processing method for the case where the buried depth of the target column is in a single layer, and the other is the data analysis and processing method for the case where the buried depth of the target column is in multiple layers. Although the specific process of the above data analysis and processing gives at most three-layer cases, according to the above data analysis and processing, the specific process of analyzing and processing the radar wave data in other multiple-layer cases can be deduced.

[0078] Specifically, taking the case of two layers with formation layer number 1 and formation layer number 2 from top to bottom in sequence as an example, a vertical slice of the three-dimensional model obtained by simulation for detecting the bottom of the target column is obtained. As Figure 8 shown, it is obtained that the buried depth of the target column is 1.5 m, the layer thickness of formation layer number 1 is 0.5 m, the relative dielectric constant of formation layer number 1 is 6.4, the resistivity of formation layer number 1 is 1000 ohm meters, the relative dielectric constant of formation layer number 2 is 5, and the resistivity of formation layer number 2 is 200 ohm meters. At this time, the horizontal distance D between the current ground penetrating radar and the target column is 0.3 m, and radar wave data is obtained by simulation, that is, a radar profile diagram, as Figure 9 shown. From Figure 9 it can be clearly seen the direct wave, the reflected wave, the diffracted wave at the intersection of the target column and the interface of the layer where the buried depth of the target column is located, and the diffracted wave at the bottom of the target column. According to the two diffracted waves, the layer velocities of formation layer number 1 and formation layer number 1 can be successively fitted to be 0.119 m / ns and 0.134 m / ns respectively; then, according to the reflection time of the reflected wave of formation layer number 1 being 8.1 ns, the layer thickness of formation layer number 1 can be calculated to be 0.476 m; then, by reading the shortest time of the diffracted wave at the bottom of the target column as 25 ns, the buried depth of the target column in formation layer number 2 can be calculated to be 1.0 m according to the foregoing formula. Combining the layer thickness of formation layer number 1 and the length of the buried depth of formation layer number 2 being 1.0 m, the buried depth of the bottom of the target column can be calculated to be 1.59 m.

[0079] In summary, the present invention provides a device for detecting the buried depth of highway guardrail columns based on ground penetrating radar. Using an existing ground penetrating radar for detection, the ground penetrating radar is placed on the road surface and moves along a direction parallel to the driving direction and at a preset distance from the target column. While moving, the diffracted wave at the bottom of the target column is detected laterally by using the beam width of the radar antenna. Through lateral detection, not only the reflected wave of the interface directly below can be detected, but also the diffracted wave at the bottom of the lateral target column can be detected. By analyzing and processing the reflected wave and the diffracted wave, the buried depth of the bottom of the target column can be calculated, enabling the device for detecting the buried depth of highway guardrail columns in the present invention to perform mobile detection on the road surface, overcoming the disadvantage of low efficiency of the traditional method. Moreover, while meeting the non-contact detection of the buried depth of highway columns, different frequency radar antennas can also be used to achieve detection with different depths and resolutions, realizing fast and high-resolution radar detection and meeting the requirements of engineering detection.

[0080] The above is only a preferred embodiment of the present invention, and it does not impose any form of limitation on the present invention. Based on the technical essence of the present invention, any simple modification, equivalent replacement, and improvement made to the above embodiments within the spirit and principle of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A device for detecting the buried depth of highway guardrail columns based on ground penetrating radar, characterized in that, It includes a ground penetrating radar and a data processing device. The ground penetrating radar is placed on the road surface. When the ground penetrating radar moves along a direction parallel to the driving direction and at a preset distance from the target column, the ground penetrating radar uses the beam width of the radar antenna to perform side detection on the target column. The data processing device is used to analyze and process the radar wave data collected by the ground penetrating radar. Among them, the data processing device includes a Windows system computer with a graphics card and data processing software. The data processing software is developed based on MATLAB and has functions such as import, processing, result display, and result export of radar data. The analysis and processing process of the data processing device is as follows: S1. Obtain the radar wave data of the ground penetrating radar in real time, detect the radar wave data. If the reflected wave of the layer interface where the buried depth of the target column is located and the diffracted waves of each diffracted point are detected, obtain the horizontal distance between the current ground penetrating radar and the target column, and go to step S2. Among them, the horizontal distance between the ground penetrating radar and the target column is directly measured with a tape measure. S2. Judge the layered medium of the reflected wave of the layer interface where the buried depth of the target column is located, and obtain the number of geological layers of the layer interface where the buried depth of the target column is located according to the judgment result of the layered medium. S3. According to the horizontal distance between the current ground penetrating radar and the target column, the number of geological layers of the layer interface where the buried depth of the target column is located, and the diffracted waves of each diffracted point, calculate the buried depth of the bottom of the target column based on the ray path of the radar wave. The step S3 includes the following steps: S31. Obtain the number of geological layers of at least one layer interface where the buried depth of the target column is located. S32. Calculate the layer velocity of each geological layer number and the arrival time of the radar wave reaching the geological layer number according to the number of geological layers of the layer interface where the buried depth of the target column is located. S33. Based on the layer velocity of the geological layer number, the arrival time of the radar wave reaching the geological layer number, the horizontal distance between the current ground penetrating radar and the target column, and the diffracted waves of each diffracted point, calculate the buried depth of the bottom of the target column according to the ray path of the radar wave. When the number of geological layers of two layer interfaces where the buried depth of the target column is located is obtained, the layer interface where the buried depth of the target column is located is two layers, that is, the buried depth of the target column from top to bottom is geological layer number 1 and geological layer number 2 in sequence. The ground penetrating radar receives the diffracted wave at the intersection of the target column and the layer interface where the buried depth of the target column is located, the diffracted wave at the bottom of the target column, and the reflected wave of the layer interface where the buried depth of the target column is located. The buried depth h of the bottom of the target column is: ； ； Among them, , h1 is the thickness of the first layer of strata, h2 is the burial depth of the target column in the second layer of strata, t is the shortest diffraction wave time at the bottom of the target column, t1 is the reflection wave reflection time of the first layer of strata, v1 is the layer velocity of the first layer of strata, v2 is the layer velocity of the first layer of strata, D is the horizontal distance between the ground penetrating radar and the target column, is the incident angle of the radar wave in the first layer of strata, is the incident angle of the radar wave in the second layer of strata.

2. The buried depth detection device for highway guardrail columns based on ground penetrating radar according to claim 1, characterized in that, When the ground penetrating radar uses the beam width of the radar antenna to perform side detection on the target column, when the diameter of the target column is less than the wavelength, diffracted waves are generated.

3. The buried depth detection device for highway guardrail columns based on ground penetrating radar according to claim 1, wherein, The side detection refers to detecting the target column deviating from directly below the radar antenna through the beam width of the radar antenna to achieve side detection of the target column.

4. The buried depth detection device for highway guardrail columns based on ground penetrating radar according to claim 1, characterized in that, The radar antenna adopts ground contact detection or inclined detection. When performing ground contact detection, the radar antenna is in close contact with the road surface. When performing inclined detection, the radar antenna is equipped with a wedge-shaped structure device, and an angle is generated between the wedge-shaped structure device and the road surface to change the beam incident angle.

5. The buried depth detection device for highway guardrail columns based on ground penetrating radar according to claim 1, characterized in that, In S3, the process of calculating the layer velocity of each stratigraphic layer number and the arrival time of the radar wave at the stratigraphic layer number based on the stratigraphic layer number of the target column burial depth interface is specifically as follows: According to the order of the stratigraphic layer numbers of the target column burial depth interface, the velocities of the radar wave reaching the stratigraphic layer numbers are successively fitted to obtain the layer velocity of the stratigraphic layer number. At the same time, based on the layer velocity of the stratigraphic layer number, the time for the radar wave to reach the stratigraphic layer number is calculated to obtain the arrival time of the radar wave at the stratigraphic layer number.

6. The buried depth detection device for highway guardrail columns based on ground penetrating radar according to claim 1, characterized in that, In S31, the stratigraphic layer numbers of at least one target column burial depth interface are obtained. When the stratigraphic layer number of one target column burial depth interface is obtained, the diffracted waves of each detected diffracted point are detected as the diffracted waves at the bottom of the target column; when the stratigraphic layer numbers of multiple target column burial depth interfaces are obtained, the diffracted waves of each detected diffracted point include the diffracted waves at the intersections of multiple target columns and the target column burial depth interface, and the diffracted waves at the bottom of the target column.

7. The device for detecting the embedding depth of highway guardrail columns based on ground penetrating radar according to claim 1, wherein, The process of calculating the burial depth at the bottom of the target column in step S33 is as follows: When the stratigraphic layer number of one target column burial depth interface is obtained, the shortest time of the diffracted wave at the bottom of the column is obtained based on the diffracted wave at the bottom of the target column. Then, based on the layer velocity of this stratigraphic layer number, the shortest time of the diffracted wave at the bottom of the column, and the horizontal distance between the ground penetrating radar and the target column, the burial depth at the bottom of the target column is calculated according to the radar wave ray path. When the stratigraphic layer numbers of multiple target column burial depth interfaces are obtained, the shortest time of the diffracted wave at the bottom of the column is obtained based on the diffracted wave at the bottom of the target column, and the incident angle of the radar wave reaching each layer interface is calculated based on the diffracted waves at the intersections of multiple target columns and the target column burial depth interface to obtain the incident angles of the radar wave at different stratigraphic layer numbers. Based on the layer velocities of multiple stratigraphic layer numbers, the arrival time of the radar wave at the stratigraphic layer number, the shortest time of the diffracted wave at the bottom of the column, the horizontal distance between the ground penetrating radar and the target column, and the incident angles of the radar wave at different stratigraphic layer numbers, the burial depth at the bottom of the target column is calculated according to the radar wave ray path.

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