Ground-penetrating radar-based device for identifying and treating segregation in large-particle-size crushed stone base courses

Abstract

The application discloses a large-particle-size graded gravel base segregation identification and treatment device based on a ground penetrating radar, and the treatment device comprises a vehicle body, a steel roller for rolling and compacting a coarse aggregate segregation area, a ground penetrating radar arranged on the vehicle body and used for acquiring a segregation grade of the coarse aggregate segregation area, a first conveying mechanism arranged on the vehicle body and used for conveying stone chips to the coarse aggregate segregation area, a tamping mechanism used for tamping the coarse aggregate segregation area to which the stone chips and water are added, a second conveying mechanism arranged on the vehicle body, and a control mechanism used for controlling the amount of the stone chips output by the first conveying mechanism and the amount of water output by the second conveying mechanism. The device integrates detection, material throwing, tamping and rolling, and the segregation grade is obtained through the ground penetrating radar; the stone chips and water are quantitatively sprayed according to the segregation degree, and the problems of shallow segregation and deep segregation of the large-particle-size graded gravel base can be solved at one time.

Description

Technical Field

[0001] This invention belongs to the field of road base construction technology, and in particular relates to a device for identifying and treating segregation in large-particle-grade crushed stone base based on ground-penetrating radar. Background Technology

[0002] The inorganic binder stabilized large-size graded crushed stone layer uses large-size crushed stone as aggregate, and a certain amount of fine aggregate and a small amount of inorganic binder to fill the voids in the aggregate. It mainly relies on the interlocking effect between the aggregates to provide strength, thus having a high load-bearing capacity.

[0003] Due to the large aggregate size, uneven distribution of coarse and fine aggregates in the mixture is often unavoidable during mixing, transportation, and paving, resulting in gradation segregation. Areas with less fine aggregate and more coarse aggregate have higher porosity. The cause of this localized problem is the deviation of various indicators during the construction stage, which is strongly correlated with the uniformity of construction. After the gradation changes, various indicators (density, porosity, dynamic modulus, etc.) deviate from the design values, mainly manifested as longitudinal, transverse, vertical, and localized non-uniformity. Local segregation also leads to uneven compaction, deviations from the design compaction degree, and over- or under-compaction. Existing research results show that segregation in inorganic binder-stabilized large-size graded crushed stone base courses will lead to poor slab integrity, easy water permeability, accelerated early damage, decreased performance indicators, and a significantly reduced service life.

[0004] Therefore, in actual on-site construction, segregation at coarse aggregate accumulation points requires manual application of stone chips. This process presents three main drawbacks. First, it's difficult to accurately control the amount and thickness of stone chips applied manually. Excessive application is uneconomical and environmentally unfriendly, severely impacting the exposed aggregate rate and leading to poor adhesion between the next process layer and the large-diameter graded crushed stone layer, affecting construction results. Insufficient application leaves large pores at the coarse aggregate segregation points unfilled, easily forming potholes and water accumulation when subjected to external environmental disturbances (vehicle loads, heavy rain), potentially causing extensive damage to the large-diameter graded crushed stone base layer and a significant decrease in strength. Second, in on-site construction, stone chips are generally compacted directly without watering after application, resulting in poor adhesion between the segregated coarse aggregate and the newly applied stone chips. Stone chips with poor adhesion to the aggregate in the upper layer are easily carried into the next area by vehicle tires, causing further localized segregation. Third, after the stone chips have been spread for a period of time, it is necessary to wait for the road roller to compact the inorganic binder after spreading the stone chips to stabilize the large-size graded crushed stone layer. During this process, the construction efficiency is low, and the moisture in the construction area is further lost due to the influence of the external environment, resulting in poor segregation treatment effect.

[0005] Existing research mainly focuses on reducing segregation of large-diameter graded crushed stone during production, transportation, and paving. However, regardless of the method used, segregation cannot be completely avoided. Current machinery for treating segregation in inorganic binder-stabilized large-diameter graded crushed stone layers is primarily manually controlled, with non-targeted stone chip spreading, offering only the function of spreading stone chips. Therefore, there is an urgent need to develop a convenient construction device that integrates stone chip spreading, moisture content adjustment, and compaction for treating segregation in inorganic binder-stabilized large-diameter graded crushed stone layers, enabling more uniform stone chip spreading. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention proposes a device for identifying and treating segregation in large-particle-size crushed stone base courses based on ground-penetrating radar, thereby accelerating construction speed, ensuring construction continuity, and guaranteeing the flatness and compaction requirements of the base course.

[0007] To achieve the above objectives, this invention discloses a device for identifying and treating segregation in large-particle-graded crushed stone base courses based on ground-penetrating radar, comprising:

[0008] The vehicle body includes rolling steel wheels for compacting the coarse aggregate segregation zone;

[0009] A ground-penetrating radar, installed on the vehicle body, is used to obtain the segregation level of the coarse aggregate segregation zone;

[0010] A first conveying mechanism is disposed on the vehicle body, and the first conveying mechanism is used to convey stone chips to the coarse aggregate segregation and aggregation area;

[0011] The tamping mechanism includes an electric telescopic tube connected to the vehicle body and a plurality of tamping tubes connected to the electric telescopic tube via connectors. The electric telescopic tube is connected to the tamping tubes. The electric telescopic tube is used to drive the tamping tubes to extend and retract relative to the coarse aggregate segregation and agglomeration area, so that the tamping tubes tampe the coarse aggregate segregation area with added stone chips and water.

[0012] A second conveying mechanism is installed on the vehicle body. The output end of the second conveying mechanism is connected to one end of the electric telescopic pipe. The second conveying mechanism is used to convey water to the electric telescopic pipe.

[0013] A control mechanism is used to control the amount of stone chips output by the first conveying mechanism and the amount of water output by the second conveying mechanism based on the segregation level of the coarse aggregate segregation agglomeration zone.

[0014] Optionally, the vehicle body also includes: a stone chip bin, a water tank, rubber front wheels, a power supply device, and handrails;

[0015] The stone chip bin is located above the first conveying mechanism and is used to supply stone chips to the first conveying mechanism; the water tank is located above the second conveying mechanism and is used to supply water to the second conveying mechanism; the power supply device is electrically connected to the control mechanism through the handrail; and the rubber front wheel is located between the ground-penetrating radar and the first conveying mechanism.

[0016] An optional method of using the treatment device includes the following steps:

[0017] Obtain the segregation grade of the coarse aggregate segregation aggregation zone;

[0018] Based on the segregation level of the coarse aggregate segregation and aggregation area, determine the amount of stone chips and water to be transported to the coarse aggregate segregation and aggregation area;

[0019] Stone chips and water are conveyed to the coarse aggregate segregation and aggregation area, and the stone chips and water are tamped to obtain a mixture of stone chips, water and coarse aggregate, thereby reducing the segregation of large-particle-size crushed stone base course;

[0020] The mixture after crushing and tamping.

[0021] Optionally, obtaining the segregation level of the coarse aggregate segregation aggregation zone includes:

[0022] Obtain the standard relative permittivity of large-size graded crushed stone base course mixture;

[0023] The relative permittivity of a large-particle-size graded crushed stone base layer was obtained by ground penetrating radar.

[0024] Based on the ratio of the standard relative permittivity to the measured relative permittivity, the segregation grade of the large-size graded crushed stone base course mixture in the target area is obtained.

[0025] Optionally, the standard relative permittivity is:

[0026] ε k =θ a ε a +θ w ε w +θ s ε s +θ G ε G +θ c ε c

[0027] θ a +θ w +θ s +θ G +θ c =1

[0028] Where, εk θ is the standard relative permittivity; a θ is the volume ratio of air in the mixture; w θ is the volume ratio of water in the mixture; s θ represents the volume ratio of fine aggregate in the mixture; G θ represents the volume ratio of coarse aggregate in the mixture; c ε represents the volume ratio of the binder in the mixture; a ε is the relative permittivity of air; w ε is the relative permittivity of water; s ε is the relative permittivity of the fine aggregate; G ε is the relative permittivity of the coarse aggregate; c is the relative permittivity of the binder.

[0029] Optionally, the measured relative permittivity is:

[0030]

[0031] Where ε is the relative permittivity; c is the speed of light, in m / s; x is the antenna spacing, in m; t1 is the propagation time of the electromagnetic wave reflected from the target when the transmitting antenna and the receiving antenna are adjacent, in s; t2 is the propagation time of the electromagnetic wave reflected from the target when the transmitting antenna and the receiving antenna are at a distance of x, in s.

[0032] Compared with the prior art, the present invention has the following advantages and technical effects:

[0033] (1) The application of radar detection technology to the treatment of segregation of large-size graded crushed stone greatly reduces the degree of segregation of large-size graded crushed stone and ensures a certain exposed aggregate rate, thus providing a good foundation for the next process.

[0034] (2) The ratio of the standard value to the measured value of the relative permittivity of the structural layer is used as an important indicator to quantitatively determine the degree of segregation of large-particle-size graded crushed stone, and this indicator is used to guide the amount of stone chips sprayed in the subsequent process.

[0035] (3) The large-diameter graded crushed stone after spreading stone chips is tamped. The shape of the tamping tube makes the coarse aggregate and stone chips more evenly mixed.

[0036] (4) This device is used for the treatment of segregation of large-particle-size graded crushed stone. It integrates multiple construction procedures, and completes the steps of spreading stone chips and water, tamping and mixing, and compaction in one go. This greatly shortens the segregation treatment time, reduces the labor intensity of construction personnel, and significantly improves the construction speed.

[0037] (5) This device integrates detection, material delivery, tamping and compaction. It can detect the segregation level of large-particle-size crushed stone base by ground-penetrating radar and spray stone chips and water quantitatively according to the degree of segregation. It can solve the problem of shallow and deep segregation of large-particle-size crushed stone base in one go. Attached Figure Description

[0038] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0039] Figure 1 This is a schematic diagram of the structure of the large-particle-size graded crushed stone base segregation identification and treatment device based on ground penetrating radar according to an embodiment of the present invention;

[0040] Figure 2 This is a schematic diagram of the specific structure of the stone chip transmission device according to an embodiment of the present invention;

[0041] Figure 3 This is a schematic diagram of the specific structure of the tamping mechanism according to an embodiment of the present invention;

[0042] Figure 4 This is a schematic diagram of the specific structure of the sprinkler and tamping pipe according to an embodiment of the present invention;

[0043] Figure 5 This is a schematic diagram of the specific structure of the electric telescopic tube according to an embodiment of the present invention;

[0044] Figure 6 This is a schematic diagram of the control mechanism according to an embodiment of the present invention;

[0045] Figure 7 This is a flowchart illustrating the usage method of the large-particle-size graded crushed stone base segregation identification and treatment device based on ground penetrating radar according to an embodiment of the present invention.

[0046] Figure 8 This is a schematic diagram illustrating the principle of radar detection of relative permittivity according to an embodiment of the present invention;

[0047] Among them, 1. Ground penetrating radar, 2. Rubber front wheel, 3. Stone chip spraying device, 4. Tamping mechanism, 5. Rolling steel wheel, 6. Handrail, 7. Control mechanism, 8. Power supply device, 9. Water tank, 10. Stone chip bin, 11. Stone chip transmission device, 12. Sprinkling and tamping pipe, 13. Electric telescopic pipe, 14. Water flow control valve. Detailed Implementation

[0048] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0049] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0050] The segregation identification and treatment device for large-particle-size graded crushed stone base layer proposed in this invention can detect the relative permittivity of the mixture in the detection area using the ground-penetrating radar 1, and compare it with the calculated standard relative permittivity to determine the degree of segregation in different areas of the inorganic binder-stabilized large-particle-size graded crushed stone layer. This allows for targeted and quantitative spraying of stone chips and water, followed by tamping and compaction, thus solving the segregation problem of large-particle-size graded crushed stone in one step. The device mainly includes a vehicle body, ground-penetrating radar 1, a first conveying mechanism, a tamping mechanism 4, a second transmission mechanism, and a control mechanism 7. Its specific structure is described in [details omitted]. Figure 1 As shown.

[0051] The vehicle body includes a compaction wheel for crushing stone chips and water in the coarse aggregate segregation area; the vehicle body also includes a stone chip bin 10, a water tank 9, rubber front wheels 2, compaction steel wheels 5, a power supply device 8, and a handrail 6. The stone chip bin 10 stores stone chips with a particle size of (0–2.36) mm, serving as the main raw material for treating the segregation of large-size aggregate. The reason the device does not mix the stone chips with water is that dry stone chips can be evenly sprayed into the depths of the segregation layer, while mixing with water will cause clumping, only treating surface segregation. The rubber front wheels 2 are positioned on both sides of the ground-penetrating radar 1, without interfering with its detection operation. The handrail 6 is used to control the initial direction of travel and to correct deviations during travel.

[0052] Ground penetrating radar 1 is mounted on the vehicle body. Ground penetrating radar 1 is used to analyze and determine the segregation level of the mixture in the target area. The ground penetrating radar 1 has a center frequency of 2GHz and a maximum detection depth of 30cm. It has obvious advantages: non-destructive, high resolution, and high efficiency.

[0053] The first conveying mechanism includes a stone chip transmission device 11 and a stone chip spraying device 3. The specific structure of the stone chip transmission device 11 is as follows: Figure 2 As shown, the first conveying mechanism is installed on the vehicle body to transport stone chips to the coarse aggregate segregation and aggregation area. The stone chip transmission device 11 can make the stone chips be uniformly transmitted to the stone chip spraying device 3. The stone chip spraying device 3 is a pressurized discharge port that is perpendicular to the width of the segregation layer and consistent with the detection width of the ground penetrating radar 1. It is used to quantitatively spray stone chips to the segregation area of ​​large-particle-size crushed stone.

[0054] The tamping mechanism 4 includes an electric telescopic pipe 13 and a water spraying and tamping pipe 12. The specific structure of the tamping mechanism 4 is as follows: Figure 3As shown, the electric telescopic pipe 13 provides power and telescopic space for the vertical insertion of the tamping pipe. The specific structure of the water spraying and tamping pipe 12 is shown in [reference needed]. Figure 4 As shown, the specific design of its tamping ruler shape is intended to improve the tamping effect. The specific structure of the electric telescopic tube 13 is as follows: Figure 5 As shown; the water spraying and tamping pipe 12 has the functions of water spraying and tamping; the second transmission mechanism is the water flow control valve 14.

[0055] For the settings and functions of control mechanism 7, see [link to settings]. Figure 6 As shown, it includes a display screen, a speed increase key, a speed decrease key, a running speed adapted to the actual degree of segregation, a moving car forward key, a moving car backward key, and a moving car pause key. The display screen includes a radar waveform graph, the moving car speed, the ambient temperature, and the relative permittivity of the detection area.

[0056] The present invention relates to a method for using a device for identifying and treating segregation in large-particle-size crushed stone base courses based on ground-penetrating radar 1. The specific steps are as follows: Figure 7 As shown:

[0057] Step 1: After the initial compaction of large-size graded crushed stone, move the large-size graded crushed stone segregation treatment device to the surface to be treated and use ground penetrating radar 1 to detect segregation.

[0058] Step 2: After moving the mobile vehicle to the coarse aggregate segregation zone, turn on the power button on the ground penetrating radar 1 and the control mechanism 7 to perform scanning and detection, and obtain the degree of segregation in the target area through data processing;

[0059] Step 3: The first and second conveying mechanisms output a quantity of stone chips and water that is appropriate for the degree of segregation on the surface of the coarse aggregate;

[0060] Step 4: The device automatically starts the tamping device 4 to mix the stone chips, water, and segregated coarse aggregate evenly.

[0061] Step 5: After tamping is completed, the mobile vehicle moves forward, and then the rolling steel wheel 5 rolls the tamped area.

[0062] Ground Penetrating Radar 1 Detection Principle, Rules for Determining the Degree of Coarse Aggregate Segregation, and Treatment Methods:

[0063] The segregation state of coarse aggregate is determined by measuring the relative permittivity of the road base layer and comparing the standard relative permittivity with the measured relative permittivity. The three-dimensional ground-penetrating radar 1 uses the common midpoint method to detect the relative permittivity. Figure 8 As shown:

[0064] According to the laws of electromagnetic wave propagation, the T1 / R1 antenna combination has:

[0065] vt1=2d1 (1)

[0066] In the formula: v is the electromagnetic wave propagation speed, in m / s; t1 is the propagation time of the electromagnetic wave reflected from the target when the transmitting antenna and the receiving antenna are adjacent, in s; d is the thickness of the structural layer, in m.

[0067] For the T2 / R2 antenna combination:

[0068]

[0069] In the formula: x is the antenna spacing in meters; t2 is the propagation time of the electromagnetic wave reflected from the target when the transmitting antenna and the receiving antenna are separated by a distance of x in seconds.

[0070] When electromagnetic waves propagate on a road surface, their propagation speed is calculated as follows:

[0071]

[0072] In the formula: c is the speed of light, in m / s; ε is the relative permittivity.

[0073] Combining the above equations, we get:

[0074]

[0075] The standard relative permittivity is related to the constituent materials; therefore, the standard relative permittivity of the inorganic binder-stabilized large-particle-size crushed stone layer is determined using the weighted proportion comprehensive method as follows:

[0076] ε k =θ a ε a +θ w ε w +θ s ε s +θ G ε G +θ c ε c (5)

[0077] θ a +θ w +θ s +θ G +θ c =1 (6)

[0078] Where: ε k θ is the standard relative permittivity; a θ is the volume ratio of air in the mixture; w θ is the volume ratio of water in the mixture; s θ represents the volume ratio of fine aggregate in the mixture; G θ represents the volume ratio of coarse aggregate in the mixture; c ε represents the volume ratio of the binder in the mixture;a ε is the relative permittivity of air; w ε is the relative permittivity of water; s ε is the relative permittivity of the fine aggregate; G ε is the relative permittivity of the coarse aggregate; c is the relative permittivity of the binder.

[0079] The degree of segregation, R, is defined as the ratio of the standard relative permittivity to the measured relative permittivity, i.e.:

[0080] R = ε k / ε (7)

[0081] In the region of fine aggregate segregation, the porosity is relatively small and the relative permittivity is generally large; while in the region of coarse aggregate segregation, the porosity is too large and the relative permittivity is generally small. The two are well correlated.

[0082] Because the tires of moving vehicles can carry fine aggregates away from the segregated area during fine aggregate segregation, and the segregation of coarse aggregate causes more severe damage, this study only focuses on the segregation of coarse aggregate. Extensive experimental research has yielded the following results:

[0083] When R < 1.6, it is described as non-separation;

[0084] When 1.6≤R<2.0, it is described as slight segregation of coarse aggregate, and is recorded as Grade I segregation;

[0085] When 2.0 ≤ R < 2.4, it is described as moderate segregation of coarse aggregate, and is recorded as Class II segregation;

[0086] When 2.4≤R, it is described as heavy segregation of coarse aggregate, and is recorded as Grade III segregation;

[0087] Finally, through experimental determination, the optimal concentration for Grade I segregation was 5 kg / m³. 2 Stone chip treatment can achieve good results; Grade II segregation uses 8kg / m³ 2 The treatment of stone chips can achieve good results; for Class III segregation, 12 kg / m³ is used. 2 The treatment with stone chips can achieve good results. The amount of water sprayed can be determined by designing the moisture content of the large-particle-size graded crushed stone layer.

[0088] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A device for identifying and treating segregation of a large particle size graded macadam base based on ground penetrating radar, characterized in that, The treatment device comprises: a vehicle body comprising a rolling steel wheel for rolling the coarse aggregate segregation accumulation area; a ground penetrating radar arranged on the vehicle body, the ground penetrating radar being used to obtain segregation levels of the coarse aggregate segregation accumulation area; a first conveying mechanism arranged on the vehicle body, the first conveying mechanism being used to convey stone chips to the coarse aggregate segregation accumulation area; a tamping mechanism comprising an electric telescopic pipe connected to the vehicle body and a plurality of tamping pipes connected to the electric telescopic pipe through a connecting piece, the electric telescopic pipe being in communication with the tamping pipes, wherein the electric telescopic pipe is used to drive the tamping pipes to extend and retract relative to the coarse aggregate segregation accumulation area, so that the tamping pipes tamp the coarse aggregate segregation accumulation area to which stone chips and water are added; a second conveying mechanism arranged on the vehicle body, an output end of the second conveying mechanism being connected to one end of the electric telescopic pipe, the second conveying mechanism being used to convey water to the electric telescopic pipe; a control mechanism for controlling the amount of stone chips output by the first conveying mechanism and the amount of water output by the second conveying mechanism based on the segregation levels of the coarse aggregate segregation accumulation area; the vehicle body further comprises a stone chip bin, a water tank, rubber front wheels, a power supply device, and a handrail; the stone chip bin is located above the first conveying mechanism and is used to provide stone chips for the first conveying mechanism; the water tank is located above the second conveying mechanism and is used to provide water for the second conveying mechanism; the power supply device is electrically connected to the control mechanism through the handrail; and the rubber front wheels are located between the ground penetrating radar and the first conveying mechanism; the use method of the treatment device comprises the following steps: obtaining segregation levels of coarse aggregate segregation accumulation areas; determining the amount of stone chips and water to be conveyed to the coarse aggregate segregation accumulation areas based on the segregation levels of the coarse aggregate segregation accumulation areas; conveying stone chips and water to the coarse aggregate segregation accumulation areas, tamping the stone chips and water, and obtaining a mixture of the stone chips, water, and coarse aggregate, so as to reduce segregation of large-diameter graded gravel base; rolling the tamped mixture; obtaining segregation levels of coarse aggregate segregation accumulation areas comprises: obtaining a standard relative permittivity of large-diameter graded gravel base mixture; obtaining a measured relative permittivity of large-diameter graded gravel base by a ground penetrating radar; obtaining segregation levels of large-diameter graded gravel base mixture of a target area based on the ratio of the standard relative permittivity to the measured relative permittivity; the standard relative permittivity is: e k = θ a e a + θ w e w + θ s e s + θ G e G + θ c e c θ a + θ w + θ s + θ G + θ c = 1 wherein ε k is the standard relative dielectric constant; θ a is the volume fraction of air in the mixture; θ w is the volume fraction of water in the mixture; θ s is the volume fraction of fine aggregate in the mixture; θ G is the volume fraction of coarse aggregate in the mixture; θ c is the volume fraction of cementitious material in the mixture; ε a is the relative dielectric constant of air; ε w is the relative dielectric constant of water; ε s is the relative dielectric constant of fine aggregate; ε G is the relative dielectric constant of coarse aggregate; and ε c is the relative dielectric constant of cementitious material.

2. The ground penetrating radar based large particle graded macadam base course segregation identification and treatment device according to claim 1, characterized in that, the measured relative permittivity is: wherein ε is the relative permittivity; c is the speed of light, with a unit of m / s; x is the antenna spacing, with a unit of m; t1 is the propagation time of a reflected electromagnetic wave of a target detected when a transmitting antenna and a receiving antenna are adjacent, with a unit of s; and t2 is the propagation time of a reflected electromagnetic wave of a target detected when the transmitting antenna and the receiving antenna are apart by x, with a unit of s.

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