Highway roadbed compaction quality inspection vehicle and inspection method

Abstract

A highway roadbed compaction quality inspection vehicle and inspection method, the inspection vehicle comprising a vehicle body, a test wheel assembly, a traction head, and a loading platform, wherein the test wheel assembly is rotatably arranged at the lower part of the vehicle body, the traction head is fixedly arranged at one end or both ends of the vehicle body, the traction head is provided with a resistance strain gauge for measuring traction force, and the loading platform is fixedly arranged at the upper part of the vehicle body; when conducting a highway roadbed compaction quality inspection, a standard load is set on the upper part of the loading platform, the traction vehicle tows the inspection vehicle over the highway roadbed to be inspected, and the highway roadbed compaction quality is judged by the change in traction force; the inspection vehicle has the advantages of simple structure, reliability, low price, high inspection efficiency, and the inspection process does not rely on the experience of the inspection personnel, is used for highway roadbed compaction quality inspection, and solves the problem of lack of accuracy and objectivity of inspection data caused by the existing compaction settlement difference method due to the lack of unified standards of vibratory rollers and the experience of inspection personnel.

Description

Technical Field

[0001] The present invention relates to the technical field of highway subgrade detection, and in particular to a highway subgrade compaction quality detection vehicle and a detection method. Background Art

[0002] The quality of highway subgrade compaction significantly impacts its strength, stability, and bearing capacity. Good subgrade compaction prevents subgrade filler material from settling and deforming during vehicle travel, ensuring driving stability and providing the subgrade with sufficient mechanical strength and stability to withstand vehicle loads.

[0003] The "Highway Roadbed and Pavement Field Testing Procedure" (JTG 3450-2019) recommends several methods for testing the compaction quality of highway subgrades, including the pit-and-sand filling method, the nuclear density-moisture meter method, the knife-ring method, and the compaction-settlement differential method. While the pit-and-sand filling method appears simple, it requires significant experience in practice and is prone to significant errors. Its use as a basis for subgrade compaction quality often leads to disputes between quality inspection agencies and construction companies over test results. Furthermore, this method damages existing subgrades and requires point-by-point testing, resulting in extremely low efficiency. The nuclear density-moisture meter method offers a relatively high level of accuracy for testing the compaction quality of highway subgrades. However, this method carries radioactive hazards and requires point-by-point testing, resulting in low efficiency. Furthermore, the nuclear instrument requires high maintenance and operation requirements, leading to its cessation by most domestic testing agencies in recent years. Among them, the ring knife method will cause some fine-grained soil inside the ring knife to be disturbed during the process of testing the dry density of the roadbed on site, resulting in inaccurate test results. This method also has the problem of point-by-point detection, resulting in low detection efficiency.

[0004] Among them, the compaction settlement difference method is a dual-control test method combined with highway roadbed construction process parameters. It uses a vibratory roller to detect the stability of the settlement and deformation of the road section to be tested to characterize the compaction degree of the highway roadbed. The detection process is a point detection of several observation sections. The detection process is continuous and will not cause damage to the existing roadbed, so the detection efficiency is relatively high. With the continuous improvement of the level of large-scale equipment in domestic highway construction, more and more highway construction projects tend to use the compaction settlement difference method to detect the compaction quality of a large amount of stone roadbed or soil-rock mixed roadbed. However, the current problem with the compaction settlement difference method is that a vibratory roller is required in the detection process, and the vibratory roller manufacturers used by various construction units during construction are If the vibratory roller used by the construction unit during the construction process is used, the test standards of the compaction settlement difference method will be inconsistent. At the same time, the test results of this method will rely more on construction experience, which will affect the accuracy and objectivity of the evaluation of the test results of the compaction settlement difference method. In addition, the existing compaction settlement difference method test process is relatively cumbersome, and it is necessary to set up several settlement observation points in several observation sections, and each observation point needs to be equipped with a fixed object. The test process also requires elevation measurement of each observation point (for the specific test process, please refer to the "Highway Roadbed and Pavement Field Test Procedure" pages 41-43). Therefore, the test process is cumbersome and the operation is complicated, which also affects the further improvement of the test efficiency of the compaction settlement difference method.

[0005] Therefore, how to provide a simple, reliable, low-cost standard testing equipment based on the existing compaction settlement difference method that does not rely on the experience of the testers is of great practical significance for simplifying the testing process, improving testing efficiency, and ensuring the accuracy and objectivity of the test results. Summary of the Invention

[0006] In order to overcome the shortcomings of the background technology, the present invention discloses a highway roadbed compaction quality inspection vehicle and inspection method. The inspection vehicle with a standard load applied to it is towed by a tractor to pass over the roadbed to be inspected, and the compaction quality of the highway roadbed is judged by the change in the traction force, so as to solve the problems of inconsistent standards, cumbersome inspection process, and lack of accuracy and objectivity in the existing compaction settlement difference method.

[0007] In order to achieve the above-mentioned purpose of the invention, the present invention adopts the following technical scheme: a highway roadbed compaction quality inspection vehicle, including a vehicle body, a test wheel assembly, a traction head, and a loading platform. The test wheel assembly is rotatably arranged at the lower part of the vehicle body, the traction head is fixedly arranged at one end or both ends of the vehicle body, the loading platform is fixedly arranged at the upper part of the vehicle body, and a loading plate is arranged on the upper part of the loading platform; when conducting a highway roadbed compaction quality inspection, the inspection vehicle is towed by a traction vehicle to pass over the roadbed to be inspected twice, and the highway roadbed compaction quality is judged by comparing the difference between the two traction forces with the standard value.

[0008] Furthermore, the test wheel assembly includes a test wheel and a test wheel shaft, and the test wheel and the test wheel shaft are rotatably connected through bearings; both ends of the test wheel shaft are fixedly arranged on the lower part of the vehicle body through test wheel brackets.

[0009] Furthermore, the traction head is arranged at a height equal to the test wheel axis.

[0010] Furthermore, a resistance strain gauge is fixedly attached to the traction head; a data collector is provided on the vehicle body; the resistance strain gauge is electrically connected to the data collector, and the data collector is communicatively connected to the data processing equipment.

[0011] Furthermore, a separation groove is provided in the middle of the outer circumference of the test wheel, and the separation groove separates the outer circumference of the test wheel into symmetrical test wheel flanges.

[0012] Furthermore, a camera is provided in the data collector.

[0013] Preferably, a highway subgrade compaction quality inspection vehicle is composed of two inspection vehicles connected in series by a connecting shaft through a traction head set at the end, forming a two-level series inspection vehicle; when conducting highway subgrade compaction quality inspection, the two series-connected inspection vehicles are towed by a traction vehicle and pass over the subgrade to be inspected at one time, and the highway subgrade compaction quality is judged by comparing the difference in traction force of the two inspection vehicles with the standard value.

[0014] Furthermore, a magnetorheological fluid damper is arranged between the test wheel and the test wheel shaft; two magnetorheological fluid dampers are provided, symmetrically arranged on both sides of the test wheel; the magnetorheological fluid damper is electrically connected to the data collector, and the working current of the magnetorheological fluid damper can be adjusted and controlled by the data collector to control the damping force of the magnetorheological fluid damper.

[0015] A method for detecting the quality of roadbed compaction by a vehicle, comprising the following steps:

[0016] S9.1. Preparation before testing: Place a loading plate of standard weight on the loading platform of the testing vehicle; mark the starting and ending positions of the road surface to be tested with lime powder or chalk; connect the testing vehicle to the rear end of the tractor by connecting one end of the tractor; and park the tractor 10-20 meters in front of the starting position of the road section to be tested. The standard weight of the loading plate is determined by formula (1):

[0017] G=Evd*l*D / Kg……(1)

[0018] In formula (1), G is the standard weight (kg) of the applied loading plate (8); Evd is the dynamic deformation modulus of the highway subgrade design index; l is the effective width (m) of the test wheel (2.1); D is the maximum diameter of the test wheel (2.1); K is the proportional coefficient of the conversion between the linear load q and the dynamic deformation modulus Evd; g is the weight of the test vehicle itself; this formula is obtained by converting the linear load q = G / L formula of the roller compaction wheel and the conversion relationship between the linear load q and the dynamic deformation modulus Evd Evd = K*q / D; where K is a dimensionless empirical coefficient, and its specific value in actual testing needs to be determined based on experiments;

[0019] S9.2. First test: Start tractor 9 and drive it along the road to be tested at a set speed of 2-4 km / h. When the camera in data collector 7 captures the marking line at the start of the test section, data collector 7 collects data from resistance strain gauge 4.4 at a set frequency and transmits it to the data processing device for storage. Data collection ends when the camera in data collector 7 captures the marking line at the end of the test section.

[0020] S9.3. Second test: Reposition tractor 9 10-20 meters before the starting point of the test section; start tractor 9 and drive it along the first driving trajectory of the test section at a set speed of 2-4 km / h; when the camera in data collector 7 captures the starting position marker of the test section, data collector 7 collects data from resistance strain gauge 4.4 at a set frequency and transmits the data to the data processing device for storage;

[0021] S9.4. Data processing:

[0022] S9.4.1. Process the resistance strain gauge data collected from the two tests, converting them into the traction force of tractor 9 on the testing vehicle during the two tests; fit the traction force data from the two tests into two traction force variation curves FL along the test section, and perform filtering and smoothing processing; merge the two smoothed traction force variation curves FL into the same traction force variation curve FL coordinate system;

[0023] S9.4.2. Determine the compaction quality of the road section according to formula (2):

[0024] F1-F2≥S……(2)

[0025] In formula (2), F1 is the traction force value of the first test at a certain point on the test section; F2 is the traction force value of the second test at a certain point on the test section (the point corresponding to the first test on the test section); S is the set judgment standard value, which is determined by actual test data;

[0026] When F1-F2 is greater than or equal to the judgment standard value S, it is determined that the corresponding point of the detected section has a compaction quality defect that does not meet the standard.

[0027] Preferably, a method for detecting the quality of roadbed compaction by a vehicle comprises the following specific steps:

[0028] S10.1. Preparation before testing: Calibrate the initial traction of the two test vehicles in series so that the initial traction of the two test vehicles is equal; set up loading plates of the same standard weight on the loading platforms of the two test vehicles; mark the starting and ending positions of the road surface to be tested with lime powder or chalk; connect the two test vehicles to the rear end of the tractor through one end of the tractor; park the tractor 10-20 meters in front of the starting position of the road section to be tested; the standard weight of the loading plate is determined by formula (1):

[0029] G=Evd*l*D / Kg……(1)

[0030] In formula (1), G is the standard weight (kg) of the applied loading plate (8); Evd is the dynamic deformation modulus of the highway subgrade design index; l is the effective width (m) of the test wheel (2.1); D is the maximum diameter of the test wheel (2.1); K is the proportional coefficient of the conversion between the linear load q and the dynamic deformation modulus Evd; g is the weight of the test vehicle itself; this formula is obtained by converting the linear load q = G / L formula of the roller compaction wheel and the conversion relationship between the linear load q and the dynamic deformation modulus Evd Evd = K*q / D; where K is a dimensionless empirical coefficient, and its specific value in actual testing needs to be determined based on experiments;

[0031] S10.2. Testing: Start the tractor and drive it along the road to be tested at a set speed of 2-4 km / h. When the camera in the data acquisition unit on the testing vehicle adjacent to the tractor captures the starting position marking of the testing section, the data acquisition units on both testing vehicles synchronously collect the output data from the resistance strain gauges on the front traction heads of the corresponding testing vehicles at a set frequency and transmit the data to the data processing device for storage. When the camera in the data acquisition unit on the testing vehicle farther from the tractor captures the ending position marking of the testing section, the data acquisition units on both testing vehicles terminate data collection.

[0032] S10.3 Data Processing:

[0033] S10.3.1. Process the resistance strain gauge data collected by the two data collectors and convert them into the traction forces of the two test vehicles; fit the traction force data of the two test vehicles into two traction force variation curves fL, respectively, and perform filtering and smoothing processing; merge the two smoothed traction force variation curves fL into the same traction force variation curve fL coordinate system; shift the second traction force variation curve f2-L to the left by ΔL so that the two traction force variation curves fL remain synchronized in the same traction force variation curve coordinate system, that is, ensure that they are at the same position on the test section; where ΔL is the distance between the test wheels of the two test vehicles;

[0034] S10.3.2. Determine the compaction quality of the road section according to formula (3):

[0035] (f1-f2')-f2≥S......(3)

[0036] In formula (3), f1 is the traction force value detected by the first test vehicle at a certain point on the test section; f2 is the traction force value detected by the second test vehicle at a certain point on the test section (the two test vehicles are at the same corresponding point on the test section); f2' is the average traction force value of the second test vehicle on the entire test section; S is the set judgment standard value, which is determined by actual test data;

[0037] When (f1-f2')-f2 is greater than or equal to the judgment standard value S, it is determined that the corresponding point of the detected road section has a compaction quality defect that does not meet the standard.

[0038] Due to the adoption of the technical solution as described above, the present invention has the following beneficial effects: a highway roadbed compaction quality inspection vehicle disclosed in the present invention includes a vehicle body, a test wheel assembly, a traction head, and a loading platform. The test wheel assembly is rotatably arranged at the lower part of the vehicle body, the traction head is fixedly arranged at one end or both ends of the vehicle body, the traction head is provided with a resistance strain gauge for measuring traction force, and the loading platform is fixedly arranged on the upper part of the vehicle body; when performing highway roadbed compaction quality inspection, a standard load is set on the upper part of the loading platform, and the traction vehicle tows the inspection vehicle to pass over the roadbed to be inspected, and the highway roadbed compaction quality is judged by the change in traction force; the inspection vehicle has the advantages of simple structure, reliability, low price, high inspection efficiency, and the inspection process does not rely on the experience of the inspection personnel. It is used for highway roadbed compaction quality inspection, and solves the problem of lack of accuracy and objectivity in the inspection results of the existing compaction settlement difference method due to inconsistent standards and experience problems of the inspection personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the appearance of the inspection vehicle of Example 1;

[0040] Figure 2 Schematic diagram of the vehicle body;

[0041] Figure 3 This is a schematic diagram of the appearance of the test wheel combination;

[0042] Figure 4 This is a schematic diagram of the appearance of the test wheel bracket;

[0043] Figure 5 This is a schematic diagram of the appearance of the traction head;

[0044] Figure 6 Schematic diagram of the appearance of the connecting shaft;

[0045] Figure 7 This is a schematic diagram of the loading platform;

[0046] Figure 8 This is a schematic diagram of the data collection process of Example 1;

[0047] Figure 9 This is a principle block diagram of the data acquisition process of Example 1;

[0048] Figure 10 This is a schematic diagram of the data processing process of Example 2;

[0049] Figure 11 This is a schematic diagram of the appearance of the inspection vehicle of Example 3;

[0050] Figure 12 This is a schematic diagram of the data collection process of Example 3;

[0051] Figure 13 This is a principle block diagram of the data acquisition process of Example 3;

[0052] Figure 14 Schematic diagram of the data processing process of Example 4.

[0053] In the figure: 1. Vehicle body; 2. Test wheel assembly; 2.1. Test wheel; 2.1.1. Separation groove; 2.1.2. Test wheel flange; 2.2. Test wheel shaft; 3. Test wheel bracket; 3.1. Upper bracket; 3.2. Lower bracket; 4. Traction head; 4.1. Traction head fixing flange; 4.2. Traction ear; 4.3. Traction head body; 4.4. Resistance strain gauge; 5. Connecting shaft; 5.1. Flattened surface; 5.2. Articulated hole; 6. Loading platform; 6.1. Base plate; 6.2. Loading plate guide column; 7. Data collector; 8. Loading plate; 9. Traction vehicle; 10. Magnetorheological fluid damper. DETAILED DESCRIPTION

[0054] The present invention can be explained in detail by the following examples, the purpose of which is to disclose the present invention and to protect all technical improvements within the scope of the present invention.

[0055] Example 1, see the attached Figure 1-7 :

[0056] See the instructions attached Figure 1 , a highway roadbed compaction quality inspection vehicle, including a vehicle body 1, a test wheel assembly 2, a traction head 4, a loading platform 6, and a data collector 7; see the attached manual Figure 2 The car body 1 is a frame structure made of welded steel; see the attached manual. Figure 3 The test wheel assembly 2 includes a test wheel 2.1 and a test wheel shaft 2.2. The test wheel 2.1 is rotatably connected to the test wheel shaft 2.2 via a bearing. The test wheel 2.1 has a width of 0.8 m and a diameter of 1.0 m. A separation groove 2.1.1 with a width of 0.4 m is provided in the middle of the outer circumference of the test wheel 2.1. The separation groove 2.1.1 separates the outer circumference of the test wheel 2.1 into symmetrical test wheel flanges 2.1.2. Each test wheel flange 2.1.2 has a width of 0.2 m. The total width of the two test wheel flanges 2.1.2 is 0.4 m, which is the effective width l of the test wheel 2.1. The test wheel 2.1 is designed with a total width of 0.8m to ensure the horizontal stability of the test vehicle during travel and to prevent the test vehicle from tipping over. The separation groove 2.1.1 with a width of 0.4m is set on the outer circumference to reduce the effective width of the test wheel 2.1. When loading the loading plate 8 with a smaller weight, a larger test load q can be obtained, thereby achieving the purpose of reducing the total weight of the test vehicle. In addition, the 0.8m width of the test wheel 2.1 is smaller than the wheelbase of the tractor to prevent the tractor wheels from pressing on the test path and having a negative impact on the test results. See the attached manual for details. Figure 4 The test wheel bracket 3 includes an upper bracket 3.1 and a lower bracket 3.2. The upper bracket 3.1 is fixedly arranged at the lower part of the vehicle body 1, and both ends of the test wheel shaft 2.2 are fixedly arranged at the lower part of the vehicle body 1 through the upper bracket 3.1 and the lower bracket 3.2; see the attached manual Figure 5 The traction head 4 includes a traction head fixing flange 4.1, a traction ear 4.2, a traction head body 4.3, and a resistance strain gauge 4.4. The traction head body 4.3 is a hollow short circular shaft. The traction head fixing flange 4.1 is fixedly set at one end of the traction head body 4.3, and the traction ear 4.2 is fixedly set at the other end of the traction head body 4.3. The traction ear 4.2 is provided with a hinge hole. The resistance strain gauge 4.4 is bonded to the outer cylindrical surface of the traction head body 4.3, so that the traction head 4 constitutes a tension sensor. The tension sensor is related to the structural design of the traction head body 4.3 and the characteristics of the resistance strain gauge 4.4, and has its optimal working range. The resistance strain gauge 4.4 is used to collect the traction force received by the inspection vehicle when it is working. The traction force received by the inspection vehicle should be within the optimal working range of the tension sensor as much as possible; see the attached manual Figure 1The traction head 4 is fixed with bolts at one end or both ends of the vehicle body 1 through the traction head fixing flange 4.1. The traction head 4 is set at a height equal to the test wheel shaft 2.2. Its purpose is to prevent the traction force of the tractor 9 from passing through the test wheel shaft 2.2 when the tractor is towing the test vehicle, and to prevent the traction force from generating a rotational torque and causing the vehicle body 1 to rotate around the test wheel shaft 2.2, thereby causing the traction head body 4.3 to generate a non-horizontal component of force, thereby affecting the accuracy of the data collected by the resistance strain gauge 4.4; the data collector 7 is fixedly set on the side of the vehicle body 1, and a camera is set in the data collector 7, and the camera faces The ground, its lens axis intersects with the axis of the test wheel shaft 2.2. The purpose of setting a camera in the data collector 7 is to shoot the detection start or end mark line set on the detection section when conducting highway roadbed compaction quality inspection. By shooting the detection start or end mark line, the data collector 7 is automatically controlled to start or end data collection on the resistance strain gauge 4.4; the resistance strain gauge 4.4 is connected to the data collector 7 through a wire, and the data collector 7 is connected to the data processing equipment through Bluetooth or micro-power wireless communication module communication. The data processing equipment is preferably a laptop computer; see the attached manual Figure 7 The loading platform 6 includes a bottom plate 6.1 and a loading plate guide column 6.2. The loading plate guide column 6.2 is fixedly arranged in the middle of the upper part of the bottom plate 6.1, and the loading platform 6 is fixedly arranged on the top of the vehicle body 1 through the bottom plate 6.1. When the inspection vehicle is working, a loading plate 8 is provided on the loading platform 6. The loading plate 8 is disc-shaped and has a through hole in the middle. The through hole cooperates with the loading plate guide column 6.2 to prevent the loading plate 8 from falling off during the operation of the inspection vehicle.

[0057] See the instructions attached Figure 8 When testing the quality of roadbed compaction, a loading plate 8 of standard weight is set on the upper part of the loading platform 6. The testing vehicle is towed by a tractor 9 to pass the roadbed to be tested twice. The quality of roadbed compaction is judged by comparing the difference between the two traction forces with the standard value; see the appendix of the manual. Figure 9 In this embodiment, the data acquisition process is as follows: the data collector 7 collects data from the resistance strain gauge 4.4 through a wire, and then transmits the data to the data processing device through a Bluetooth or micro-power wireless communication module.

[0058] The working principle of the highway subgrade compaction quality inspection vehicle is explained as follows: During the highway subgrade compaction construction process, the initial subgrade filler density is low. During the compaction process of the vibratory roller, the filler with low density absorbs the vibration compaction energy and produces a large plastic deformation, and the filler density increases; as the number of compaction times of the vibratory roller increases, the filler density gradually increases further, and the absorption of vibration compaction energy decreases, and the dynamic deformation modulus (Evd) used to evaluate the subgrade compaction quality gradually increases until it reaches the design index of the highway subgrade; when the dynamic deformation modulus (Evd) reaches the design index, the inspection vehicle is under the load of the loading plate 8 loaded with a standard weight, that is, when the test wheel 2.1 passes over the road surface to be inspected under the test load q, the highway subgrade only undergoes elastic deformation, and no longer undergoes plastic deformation. Therefore, the inspection vehicle passes over the road surface to be inspected twice, and the two traction forces F1 and F2 detected are as follows: F2 is equal; if the dynamic deformation modulus (Evd) of the highway pavement does not meet the design index, when the inspection vehicle passes over the road surface to be inspected for the first time under the action of the inspection load q, the highway roadbed will not only undergo elastic deformation, but also undergo greater plastic deformation (compared to the second time passing over the road surface to be inspected), and when the inspection vehicle passes over the road surface to be inspected for the second time under the action of the inspection load q, the plastic deformation becomes smaller (compared to the first time passing over the road surface to be inspected) or no plastic deformation occurs, and the energy of the plastic deformation of the road surface to be inspected comes from the traction of the inspection vehicle. Therefore, the traction force will change when the inspection vehicle passes over the road surface to be inspected twice, that is, the traction force F1 when passing over the road surface to be inspected for the first time will be greater than the traction force F2 when passing over the road surface to be inspected for the second time, and the magnitude of the two traction forces will change. Therefore, the difference between the two traction forces can be compared with the standard value to determine whether the compaction quality of the highway roadbed meets the design index;

[0059] From the working principle of the above-mentioned highway roadbed compaction quality inspection vehicle, it can be seen that its inspection process is completely unrelated to the manufacturer and performance of the vibratory roller used in the construction project. This avoids the problem of lack of accuracy and objectivity in the inspection results caused by the previous compaction settlement difference method in the highway roadbed compaction quality inspection process, where the vibratory rollers used as inspection equipment are not uniform and the entire inspection process relies on the operating experience of the inspectors.

[0060] Example 2: A method for detecting the quality of roadbed compaction using a vehicle based on Example 1, wherein the specific steps are as follows:

[0061] S9.1. Preparation before testing: Place a standard weight loading plate 8 on the loading platform 6 of the testing vehicle; mark the starting and ending positions of the road surface to be tested with lime powder or chalk; connect the testing vehicle to the rear end of the tractor 9 via one end of the tractor head 4; and park the tractor 9 20 meters in front of the starting position of the road section to be tested. The standard weight of the loading plate 8 is determined by formula (1):

[0062] G=Evd*l*D / Kg……(1)

[0063] In formula (1), G is the standard weight (kg) of the applied loading plate (8); Evd is the dynamic deformation modulus of the highway subgrade design index; l is the effective width of the test wheel (2.1), which is 0.4m; D is the maximum diameter of the test wheel (2.1), which is 0.8m; K is the proportional coefficient of the conversion between the linear load q and the dynamic deformation modulus Evd; g is the weight of the inspection vehicle itself, which is 5.0kN; this formula is obtained by converting the linear load q=G / L formula of the roller compaction wheel and the conversion relationship between the linear load q and the dynamic deformation modulus Evd Evd=K*q / D; wherein K is a dimensionless empirical coefficient, and its value is related to the filler soil type and compaction process of the specific project. In the present invention, the compaction process is actually the smooth passage of the inspection vehicle, which is different from the vibration compaction of the vibratory roller. There is no vibration compaction parameter, so the K value is actually only related to the filler soil type;

[0064] The standard weight G (Kg) of the loading plate (8) applied can be directly determined through experiments; the specific method is: first, the dynamic deformation modulus Evd test is performed on the road section to be tested, and when it is determined that the dynamic deformation modulus Evd of the road section to be tested reaches the design index, the test vehicle is tested; during the test process of the test vehicle, the weight of the loading plate 8 is gradually increased until F1 / F2 is greater than 1.0 during the test process, which is the standard weight G (Kg) of the loading plate 8 applied; for highway subgrades using different fillers and different design standards, the standard weight (Kg) of the loading plate 8 applied is different. With the accumulation of test data, a query table of the standard weight (Kg) of the loading plate 8 can be formed. When the quality test of the highway subgrade compaction is actually performed, the standard weight G of the loading plate 8 of the road section to be monitored is obtained by querying the query table of the standard weight (Kg) of the loading plate 8 according to the filler used in the highway subgrade to be monitored and the design standard of the dynamic deformation modulus Evd;

[0065] If the dynamic deformation modulus Evd design standard is used to convert the load plate (8) standard weight G through the proportional coefficient K, the value of the proportional coefficient K is obtained by substituting the standard weight G (kg) of the load plate 8 measured in the above experimental process into formula (1) to calculate the corresponding K value; for example, when the roadbed uses clay filler and its dynamic deformation modulus Evd design standard is 20MPa, 30MPa, and 40MPa, when the standard weight G of the load plate 8 applied to the inspection vehicle is measured to be 20kN, 35kN, and 45kN respectively, the calculated K values ​​are:

[0066] K1=Evd*l*D / G=20*0.4*0.8 / (20+5)=0.256

[0067] K2=Evd*l*D / G=30*0.4*0.8 / (35+5)=0.240

[0068] K3=Evd*l*D / G=40*0.4*0.8 / (45+5)=0.256

[0069] The above K value is basically linear, and its average value Kavg=0.251 is taken as the proportional coefficient of the conversion between the linear load q and the dynamic deformation modulus Evd when the highway roadbed uses clay soil filler;

[0070] S9.2. First test: Start tractor 9 and drive it along the road to be tested at a set speed of 3 km / h. When the camera in data collector 7 captures the starting position marker of the test section, data collector 7 collects the output data of resistance strain gauge 4.4 at a set frequency and transmits it to the data processing device for storage. Data collection ends when the camera in data collector 7 captures the ending position marker of the test section.

[0071] S9.3. Second test: Reposition tractor 9 20 meters before the starting point of the test section; start tractor 9 and drive along the first driving trajectory of the test section at a set speed of 3 km / h, ensuring that the two driving trajectories overlap; when the camera in data collector 7 captures the marking line at the starting position of the test section, data collector 7 collects data from resistance strain gauge 4.4 at a set frequency and transmits the data to the data processing device for storage; data collection ends when the camera in data collector 7 captures the marking line at the end position of the test section.

[0072] S9.4. Data processing:

[0073] S9.4.1. Process the data collected from the resistance strain gauge 4.4 during the two tests and convert them into the traction force of the tractor 9 on the test vehicle during the two tests; fit the traction force data from the two tests into two traction force variation curves FL, perform filtering and smoothing processing, and eliminate high-frequency interference signals; see the appendix of the manual. Figure 10 The two smoothed traction force change curves FL are merged into the same traction force change curve FL coordinate system; in the traction force change curve FL coordinate system, the S axis represents the distance from the detection starting line, and the F axis represents the traction force magnitude;

[0074] S9.4.2. Determine the compaction quality of the road section according to formula (2):

[0075] F1-F2≥S……(2)

[0076] In formula (2), F1 is the traction value of the first test at a certain point on the test section; F2 is the traction value of the second test at a certain point on the test section; S is the set judgment standard value, which is determined by actual test data; the test determination method of the judgment standard value S is as follows: during the test process, the dynamic deformation modulus Evd test is performed on the road section where F1-F2>0. When it is detected that the dynamic deformation modulus Evd does not meet the design standard, the value of F1-F2 at this time is defined as the temporary judgment standard value; the temporary judgment standard value will gradually approach a fixed value as the number of tests increases, and finally the fixed value that the temporary judgment standard value gradually approaches is used as the judgment standard value S;

[0077] In the traction force variation curve FL, the values ​​are taken at intervals of 0.5 m, and the difference between F1 and F2 is calculated using formula (2). When the difference is greater than or equal to the set judgment standard value S, it is determined that the corresponding point of the test section has a compaction quality defect that does not meet the standard. When the traction force variation curve FL is used to judge the compaction quality of the test section, the location of the compaction quality defect that does not meet the standard of the test section can be intuitively observed.

[0078] Example 3, see the attached Figure 11 :

[0079] A roadbed compaction quality inspection vehicle, wherein two inspection vehicles are connected in series by a traction head 4 provided at the end and a connecting shaft 5, forming a two-stage series inspection vehicle, wherein the traction head 4 and the connecting shaft 5 are articulated and connected with each other with a gap, allowing the second inspection vehicle to float to a certain extent in the horizontal and pitch directions relative to the first inspection vehicle; see the attached manual for details. Figure 12 When the highway subgrade compaction quality inspection vehicle of this embodiment is used to inspect the highway subgrade compaction quality, two inspection vehicles connected in series are towed by a tractor 9 and pass over the subgrade to be inspected at one time. The highway subgrade compaction quality is judged by comparing the difference in traction force between the two inspection vehicles with the standard value; see the attached specification for details. Figure 13 The data collection process of the two-stage series detection vehicle using this embodiment is as follows: after one traction test, the data of the corresponding resistance strain gauge 4.4 is correspondingly collected by the data collector 7 provided on each of the two detection vehicles, and then the data collector 7 provided on each of the two detection vehicles transmits the data to a data processing device via Bluetooth or a micro-power wireless communication module, so that the traction force values ​​of the two detection vehicles can be obtained, thereby greatly improving the detection efficiency; in addition, the two-stage series detection vehicle can ensure that the driving track of the second detection vehicle overlaps, thereby improving the operational difficulty of ensuring the overlapping driving tracks of the two traction detection vehicles in the embodiment;

[0080] In this embodiment, a magnetorheological fluid damper 10 may be further provided between the test wheel 2.1 and the test wheel shaft 2.2. Two magnetorheological fluid dampers 10 are provided, symmetrically arranged on both sides of the test wheel 2.1, and electrically connected to the data collector 7. The provision of the magnetorheological fluid damper 10 can change the damping between the test wheel 2.1 and the test wheel shaft 2.2, thereby achieving adjustment of the initial traction of the two test vehicles.

[0081] Example 4: A method for detecting the quality of roadbed compaction by a vehicle based on Example 3, wherein the specific steps are as follows:

[0082] S10.1. Preparation before testing: Adjust the initial traction of the two test vehicles to maintain the same; set up loading plates 8 of the same standard weight on the loading platform 6 of the two-stage tandem test vehicle; mark the starting and ending positions of the road surface to be tested with lime powder or chalk; the two-stage tandem test vehicle is connected to the rear end of the tractor 9 via a traction head 4 at one end; the tractor 9 is parked 15 meters in front of the starting position of the road section to be tested; the standard weight of the loading plate 8 is determined by formula (1):

[0083] G=Evd*l*D / Kg……(1)

[0084] In formula (1), G is the standard weight (kg) of the applied loading plate (8); Evd is the dynamic deformation modulus of the highway subgrade design index; l is the effective width of the test wheel 2.1, which is 0.4m long; K is the proportional coefficient of the conversion between the linear load q and the dynamic deformation modulus Evd; g is the weight of the test vehicle itself, which is 5.0kN; this formula is obtained by converting the linear load q = G / L formula of the roller and the conversion relationship between the linear load q and the dynamic deformation modulus Evd Evd = K*q; the proportional coefficient K is determined by experiment;

[0085] S10.2. Testing: Start tractor 9 and drive it along the road to be tested at a set speed of 3 km / h. When the camera in the data collector 7 on the testing vehicle adjacent to tractor 9 captures the starting position marking of the testing section, the data collectors 7 on both testing vehicles synchronously collect the output data of the resistance strain gauge 4.4 on the traction head 4 at the front end of the corresponding testing vehicle at a set frequency and transmit it to the data processing device for storage. When the camera in the data collector 7 on the testing vehicle farther away from tractor 9 captures the ending position marking of the testing section, the data collectors 7 on both testing vehicles terminate data collection.

[0086] S10.3 Data Processing:

[0087] S10.3.1. Process the data of the resistance strain gauge 4.4 collected by the two data collectors 7 and convert them into the traction of the two test vehicles; fit the traction data of the two test vehicles into two traction change curves fL respectively, and perform filtering and smoothing processing; see the appendix of the manual Figure 14 , the two smoothed traction change curves fL are merged into the same traction change curve fL coordinate system; in this embodiment, since there is a distance difference ΔL between the test wheels 2.1 of the two test vehicles arranged in front and behind, the second traction change curve f2-S needs to be translated to the left by ΔL so that the two traction change curves fL remain synchronized in the same traction change curve coordinate system, that is, ensure that the positions of the two traction change curves fL are the same in the test section; where ΔL is the distance between the test wheels (2.1) of the two test vehicles;

[0088] S10.3.2. Determine the compaction quality of the road section according to formula (3):

[0089] (f1-f2')-f2≥S......(3)

[0090] In formula (3), f1 is the traction force value detected by the first detection vehicle at a certain point on the detection section; f2 is the traction force value detected by the second detection vehicle at a certain point on the detection section; f2' is the average traction force value of the second detection vehicle in the entire detection section; S is the set judgment standard value, which is determined by actual test data. In this embodiment, the test determination method of the judgment standard value S is different from that in the first embodiment: during the detection process, the dynamic deformation modulus Evd is tested for the road section where f1 / f2>0.5. When it is detected that the dynamic deformation modulus Evd does not meet the design standard, the value of (f1-f2')-f2 is defined as the temporary judgment standard value; the temporary judgment standard value will gradually approach a fixed value as the number of tests increases, and finally the fixed value to which the temporary judgment standard value gradually approaches is used as the judgment standard value S;

[0091] In the compaction quality inspection of the inspection section in this embodiment, the reason why the compaction quality judgment formula of the inspection section is different from that of the first embodiment is that: because the traction force value f1 detected by the first inspection vehicle at a certain point on the inspection section includes the traction force value f2 detected by the second inspection vehicle at a certain point on the inspection section, the traction force value f1 needs to be subtracted from the influence of the traction force value f2 before the traction force value f1 and the traction force value f2 can be compared on the same basis. Therefore, the term (f1-f2') exists to eliminate the traction force value f2 included in the traction force value f1; when (f1-f2')-f2 is greater than or equal to the judgment standard value S, it is determined that the compaction quality defect of the corresponding point on the inspection section does not meet the standard exists;

[0092] It should be noted that in this embodiment, since there are two test vehicles, to ensure the accuracy of the test results, the initial traction (generated by the friction of the bearings rotatably connected to the test wheel 2.1 and the test wheel shaft 2.2) of the two test vehicles must be equal. For example, when conducting a calibration test on a cement road surface, the test data should be f1=2*f2. If f1>2*f2 during the calibration test, it means that the initial traction of the first test vehicle is greater than that of the second test vehicle. Therefore, before the actual test, it is necessary to adjust the initial negative clearance state of the bearings rotatably connected to the test wheel 2.1 and the test wheel shaft 2.2 of the first test vehicle to reduce the initial traction, or to adjust the initial negative clearance state of the bearings rotatably connected to the test wheel 2.1 and the test wheel shaft 2.2 of the second test vehicle to increase the initial traction, so that the initial traction of the two test vehicles remains consistent. However, this adjustment method is relatively cumbersome.

[0093] Preferably, another method for adjusting the initial traction of the two test vehicles is: magnetorheological fluid dampers 10 are symmetrically arranged on both sides of the test wheels 2.1 of the two test vehicles, and the initial traction of the two test vehicles is kept consistent by adjusting the resistance of the magnetorheological fluid dampers 10 in the two test vehicles. The symmetrical arrangement of the magnetorheological fluid dampers 10 prevents the test vehicles from deviating due to the different resistance on both sides of the test wheels 2.1 during driving. In addition, the magnetorheological fluid dampers 10 are installed on the test vehicles, which can not only ensure that the initial traction of the two test vehicles is consistent, but also can be designed according to the dynamic deformation modulus Evd of the road surface to be tested in the on-site work (for example, the dynamic deformation modulus E When the vd design index is high, the initial traction of the inspection vehicle will be small; when the dynamic deformation modulus Evd design index is low, the initial traction of the inspection vehicle will be large). The initial traction of the two inspection vehicles is adjusted so that the resistance strain gauge 4.4 is in the optimal linear working range, thereby improving the detection accuracy of the traction force. When the magnetorheological fluid damper 10 is installed on the inspection vehicle, the magnetorheological fluid damper 10 is electrically connected to the data collector 7, and the data collector 7 adjusts the resistance of the magnetorheological fluid damper 10. This method of adjusting the initial traction of the two inspection vehicles is more convenient and quick, and greatly shortens the preparation time before the highway subgrade compaction quality inspection vehicle is inspected.

[0094] The parts not described in detail in this invention are prior art.

Claims

1. A highway subgrade compaction quality inspection vehicle, characterized by: The invention comprises a vehicle body (1), a test wheel assembly (2), a traction head (4), and a loading platform (6), wherein the test wheel assembly (2) is rotatably arranged at the lower part of the vehicle body (1), the traction head (4) is fixedly arranged at one end or both ends of the vehicle body (1), the loading platform (6) is fixedly arranged at the upper part of the vehicle body (1), and a loading plate (8) is arranged on the upper part of the loading platform (6); a resistance strain gauge (4.4) is fixedly attached to the traction head (4); when performing a roadbed compaction quality inspection, the inspection vehicle is towed by the traction vehicle (9) through the traction head (4) twice to pass over the roadbed to be inspected, and the traction force is measured twice by the resistance strain gauge (4.4) fixedly attached to the traction head (4); the roadbed compaction quality of the highway is judged by comparing the difference between the two traction forces with the standard value; the judgment formula of the compaction quality of the inspection section is as follows: F1-F2≥S; In the above formula, F1 is the traction value of the first test at a certain point on the test section; F2 is the traction value of the second test at a certain point on the test section; S is the set judgment standard value, which is determined by actual test data; when F1-F2 is greater than or equal to the judgment standard value S, it is determined that the corresponding point on the test section has a compaction quality defect that does not meet the standard.

2. The highway subgrade compaction quality inspection vehicle according to claim 1, characterized in that: The test wheel assembly (2) comprises a test wheel (2.1) and a test wheel rotating shaft (2.2). The test wheel (2.1) and the test wheel rotating shaft (2.2) are rotatably connected via bearings; both ends of the test wheel rotating shaft (2.2) are fixedly arranged on the lower part of the vehicle body (1) via a test wheel bracket (3).

3. The highway subgrade compaction quality inspection vehicle according to claim 1 is characterized by: The traction head (4) is set at the same height as the test wheel shaft (2.2).

4. The highway subgrade compaction quality inspection vehicle according to any one of claims 1 to 3, characterized in that: A data collector (7) is provided on the vehicle body (1); the resistance strain gauge (4.4) is electrically connected to the data collector (7), and the data collector (7) is communicatively connected to a data processing device.

5. The highway subgrade compaction quality inspection vehicle according to claim 4, characterized in that: A separation groove (2.1.1) is provided in the middle of the outer circumference of the test wheel (2.1), and the separation groove (2.1.1) separates the outer circumference of the test wheel (2.1) into symmetrical test wheel flanges (2.1.2).

6. The highway subgrade compaction quality inspection vehicle according to claim 5, characterized in that: The data collector (7) is provided with a camera.

7. A highway subgrade compaction quality inspection vehicle according to claim 6, characterized in that: The two inspection vehicles are connected in series by a connecting shaft (5) through a traction head (4) provided at the end, forming a two-stage series inspection vehicle; when performing a roadbed compaction quality inspection, the two series-connected inspection vehicles are towed by a traction vehicle (9) and pass over the roadbed to be inspected at one time, and the roadbed compaction quality is judged by comparing the difference in traction between the two inspection vehicles with a standard value.

8. A highway subgrade compaction quality inspection vehicle according to claim 7, characterized in that: A magnetorheological fluid damper (10) is provided between the test wheel (2.1) and the test wheel rotating shaft (2.2); two magnetorheological fluid dampers (10) are provided and symmetrically arranged on both sides of the test wheel (2.1); and the magnetorheological fluid dampers (10) are electrically connected to the data collector (7).

9. A method for detecting the roadbed compaction quality of a roadbed using the vehicle for detecting the roadbed compaction quality of a roadbed according to claim 6, characterized in that: The following steps are involved: S9.

1. Preparation before testing: Set a loading plate (8) of standard weight on the loading platform (6) of the testing vehicle; mark the starting and ending positions of the road surface to be tested; connect the testing vehicle to the rear end of the tractor (9) through one end of the tractor head (4); the tractor (9) is parked 10-20 meters in front of the starting position of the road section to be tested; the standard weight of the loading plate (8) is determined by formula (1): G=Evd*l*D / Kg……(1) In formula (1), G is the standard weight (kg) of the applied loading plate (8); Evd is the dynamic deformation modulus of the highway subgrade design index; l is the effective width (m) of the test wheel (2.1); D is the maximum diameter of the test wheel (2.1); K is the proportional coefficient of the conversion between the linear load q and the dynamic deformation modulus Evd; g is the weight of the test vehicle itself; this formula is obtained by converting the linear load q = G / L formula of the roller compaction wheel and the conversion relationship between the linear load q and the dynamic deformation modulus Evd Evd = K*q / D; where K is a dimensionless empirical coefficient, and its specific value in actual testing needs to be determined based on experiments; S9.2, first detection: start the tractor (9), and the tractor (9) travels along the road to be detected at a set speed of 2-4 km / h; when the camera in the data acquisition device (7) captures the starting position mark line of the detection section, the data acquisition device (7) collects the output data of the resistance strain gauge (4.4) at a set frequency and transmits it to the data processing device for storage; when the camera in the data acquisition device (7) captures the end position mark line of the detection section, the data acquisition ends; S9.3, second test: the tractor (9) is parked again 10-20 meters before the starting position of the road section to be tested; the tractor (9) is started, and the tractor (9) travels along the first driving trajectory of the test section at a set speed of 2-4 km / h; when the camera in the data collector (7) captures the marking line of the starting position of the test section, the data collector (7) collects data from the resistance strain gauge (4.4) at a set frequency and transmits the data to the data processing device for storage; when the camera in the data collector (7) captures the marking line of the end position of the test section, the data collection ends; S9.

4. Data processing: S9.4.

1. Process the resistance strain gauge (4.4) data collected during the two tests and convert them into the traction force of the tractor (9) on the test vehicle during the two tests; fit the traction force data of the two tests into two traction force change curves FL and perform filtering and smoothing processing; merge the two smoothed traction force change curves FL into the same traction force change curve FL coordinate system; S9.4.

2. Determine the compaction quality of the road section according to formula (2): F1-F2≥S……(2) In formula (2), F1 is the traction force value of the first test at a certain point on the test section; F2 is the traction force value of the second test at a certain point on the test section; S is the set judgment standard value, which is determined by actual test data; When F1-F2 is greater than or equal to the judgment standard value S, it is determined that the corresponding point of the detected section has a compaction quality defect that does not meet the standard.

10. A method for detecting the roadbed compaction quality of the roadbed compaction quality detection vehicle according to claim 8, characterized in that: The following steps are involved: S10.

1. Preparation before testing: Calibrate the initial traction of the two test vehicles in series so that the initial traction of the two test vehicles is equal; A loading plate (8) of the same standard weight is set on the loading platform (6) of the secondary series test vehicle; marking lines are made at the starting position and the ending position of the road surface to be tested; the secondary series test vehicle is connected to the rear end of the tractor (9) through a traction head (4) at one end; the tractor (9) is parked 10-20 meters in front of the starting position of the road section to be tested; wherein the standard weight of the loading plate (8) is determined by formula (1): G=Evd*l*D / Kg……(1) In formula (1), G is the standard weight (kg) of the applied loading plate (8); Evd is the dynamic deformation modulus of the highway subgrade design index; l is the effective width (m) of the test wheel (2.1); D is the maximum diameter of the test wheel (2.1); K is the proportional coefficient of the conversion between the linear load q and the dynamic deformation modulus Evd; g is the weight of the test vehicle itself; this formula is obtained by converting the linear load q = G / L formula of the roller compaction wheel and the conversion relationship between the linear load q and the dynamic deformation modulus Evd Evd = K*q / D; where K is a dimensionless empirical coefficient, and its specific value in actual testing needs to be determined based on experiments; S10.2, detection: start the tractor (9), and the tractor (9) travels along the road to be detected at a set speed of 2-4 km / h; when the camera in the data collector (7) on the detection vehicle adjacent to the tractor (9) captures the starting position mark line of the detection section, the data collectors (7) on the two detection vehicles synchronously collect the output data of the resistance strain gauge (4.4) on the traction head (4) at the front end of the corresponding detection vehicle at the set frequency, and transmit it to the data processing device for storage; when the camera in the data collector (7) on the detection vehicle far away from the tractor (9) captures the end position mark line of the detection section, the data collectors (7) on the two detection vehicles end data collection; S10.3 Data Processing: S10.3.

1. Process the resistance strain gauge (4.4) data collected by the two data collectors (7) and convert them into the traction of the two test vehicles; fit the traction data of the two test vehicles into two traction change curves fL respectively, and perform filtering and smoothing processing; merge the two smoothed traction change curves fL into the same traction change curve fL coordinate system; shift the second traction change curve f2-L to the left by △L so that the two traction change curves fL remain synchronized in the same traction change curve coordinate system, that is, ensure that they are the same in the position of the test section; where △L is the distance between the test wheels (2.1) of the two test vehicles; S10.3.

2. Determine the compaction quality of the road section according to formula (3): (f1-f2')-f2≥S......(3) In formula (3), f1 is the traction force value detected by the first detection vehicle at a certain point on the detection road section; f2 is the traction force value detected by the second detection vehicle at a certain point on the detection road section; f2' is the average traction force value of the second test vehicle on the entire test section; S is the set judgment standard value, which is determined by actual test data; When (f1-f2')-f2 is greater than or equal to the judgment standard value S, it is determined that the corresponding point of the detected road section has a compaction quality defect that does not meet the standard.

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