Methods and systems for testing compaction of fine sand roadbed

Abstract

This invention provides a method and system for compaction testing of fine sand subgrade. The method includes: acquiring detection location information and corresponding vibration signals at multiple detection locations during the compaction process of a road roller; inputting the detection location information and vibration signals into a continuous compaction quality testing index model; wherein the continuous compaction quality testing index model includes a standard curve and repetition period data; comparing the detection location information and vibration signals with the standard curve or repetition period data to determine the compaction quality testing result at each detection location of the subgrade. This invention establishes a continuous compaction quality testing model for subgrade, including the subgrade fill quality, vibration frequency, amplitude, and vehicle speed, thus demonstrating the influence of the subgrade fill material on the continuous compaction quality testing values. Furthermore, the continuous compaction quality evaluation model quantitatively considers the influence of vibration compaction parameters, resulting in high continuous testing accuracy.

Description

Technical Field

[0001] This invention relates to the field of road inspection, specifically to a method and system for testing the compaction of fine sand roadbed. Background Technology

[0002] Compaction of fill material is a key step in roadbed construction, enhancing its mechanical properties and stability by increasing its density. The quality and efficiency of fill material compaction have always been crucial concerns in high-speed railway roadbed construction. Compaction quality directly affects the operational safety of the railway line, while compaction efficiency directly impacts the construction period and project investment.

[0003] Traditional compaction quality testing methods are point-based control methods, including deflection method, bearing plate method, nuclear density meter method, etc. These methods have certain shortcomings: they are time-consuming and labor-intensive, have few sampling points, and are difficult to reflect the compaction quality at each point; they cannot provide real-time feedback on compaction quality during road compaction, and are prone to over-compaction or under-compaction.

[0004] Currently, by collecting vibration signals from specific locations of the roller during the compaction process, a real-time compaction quality detection method based on indicators such as harmonic ratio, vibration modulus, effective value of acceleration, and foundation reaction force has been proposed. However, these indicators lack certain physical basis, and the understanding of the feedback vibration signals is unclear. As a result, due to the large fluctuation of vibration signals during actual compaction, it is difficult to accurately determine the compaction quality of the roadbed, leading to poor practical application results. Summary of the Invention

[0005] Based on this, the present invention proposes a method and system for detecting compaction of fine sand roadbed, which can determine the quality of roadbed compaction in real time, and the detection process is relatively simple.

[0006] This invention provides a method for testing the compaction of fine sand roadbed, comprising:

[0007] Acquire detection location information and corresponding vibration signals at multiple detection locations during the compaction operation of the road roller;

[0008] The detection location information and the detection vibration signal are input into the continuous detection index model of compaction quality;

[0009] The continuous compaction quality detection index model includes a standard curve and repetition period data.

[0010] The detection location information and the detection vibration signal are compared with the standard curve or the repetition period data to determine the compaction quality detection result of each detection location of the roadbed.

[0011] Furthermore, the continuous compaction quality detection index model is obtained through the following steps:

[0012] The continuous detection index model for compaction quality is constructed by relating the vibration signals obtained from the road roller traveling along a prescribed route within the work site to the compaction quality.

[0013] The continuous monitoring index model for compaction quality is trained.

[0014] Furthermore, training the continuous compaction quality detection index model includes:

[0015] A standard curve was obtained by comparing the difference before and after compaction operations were carried out in a specified area;

[0016] The road roller is made to travel along a prescribed route within the work site, and the real-time position information and real-time vibration signal of the road roller are obtained repeatedly within the repeat cycle.

[0017] The standard curve, the repeated real-time position information, and the repeated real-time vibration signal are input into the continuous compaction quality detection index model.

[0018] When the repetitive real-time vibration signal approaches the standard curve, the continuous detection index model of compaction quality is obtained.

[0019] Furthermore, the standard curve obtained by comparing the difference before and after compaction operations within a specified area includes:

[0020] Acquire the first vibration signal of the road roller operating within the specified area;

[0021] Acquire the second vibration signal after the road roller performs compaction operations within the specified area;

[0022] The first vibration signal and the second vibration signal are input into the continuous compaction quality detection index model to obtain the standard curve.

[0023] Furthermore, the first vibration signal and the second vibration signal are a combination of N signals obtained by continuous compaction vibration detection using different vibration frequencies, vehicle speeds and amplitudes, where N is a positive integer.

[0024] Furthermore, when the vibration signals received by the road roller at the same position are nearly identical under the same vibration frequency, vehicle speed, and amplitude, the vibration signal obtained at this time is the second vibration signal.

[0025] Furthermore, training the continuous compaction quality detection index model includes:

[0026] The road roller is made to travel along a prescribed route within the work site, and the first real-time position information and the first real-time vibration signal of the road roller are obtained in the first cycle.

[0027] The first real-time location information and the first real-time vibration signal are input into the continuous compaction quality detection index model as the first cycle data.

[0028] The road roller is made to travel along a prescribed route within the work site, and the real-time position information and real-time vibration signal of the road roller are obtained repeatedly within the repeat cycle.

[0029] The repeated real-time location information and the repeated real-time vibration signal are input into the continuous compaction quality detection index model as repeated cycle data.

[0030] When the difference between the repeated period data and the first period data is the largest, the continuous compaction quality detection index model is obtained.

[0031] The specified route includes the specified area.

[0032] Furthermore, the first real-time location information includes a combination of N location information of the road roller in the first cycle, where N is a positive integer.

[0033] Furthermore, the first real-time vibration signal includes: a combination of N vibration signals corresponding to the position information obtained by continuously detecting compaction vibration with the same vibration frequency, the same vehicle speed and amplitude when the road roller is located at N position information of the first real-time position information, where N is a positive integer.

[0034] This invention provides a system for implementing a method for detecting compaction of fine sand subgrade, comprising:

[0035] The road roller is equipped with an acceleration sensor, an amplitude detection module, an on-board signal analysis and processing module, and an on-board display module;

[0036] The acceleration sensor is mounted on the vibrating wheel to collect the vertical acceleration signal of the vibrating wheel;

[0037] The amplitude detection module detects the included angle of the eccentric blocks of the road roller;

[0038] The three-dimensional position information, speed information, acceleration signal, and amplitude information of the road roller are all transmitted to the on-board information analysis and processing module;

[0039] The onboard information analysis and processing module detects the instantaneous vibration frequency of the road roller by performing Hilbert-Huang transform on the acceleration signal;

[0040] The vehicle-mounted display module displays the current location of the road roller, vibration compaction parameters, and areas with acceptable and unacceptable compaction quality in real time.

[0041] The satellite positioning receiving module is used to acquire the detection position information of the detection position during the compaction operation of the road roller;

[0042] The detected location information includes the three-dimensional spatial location information and travel speed information of the road roller.

[0043] As can be seen from the above technical solutions, the method and system for detecting compaction of fine sand subgrade provided by the present invention have the following beneficial effects:

[0044] This invention establishes a continuous detection model for subgrade compaction quality, which includes the quality of the bottom subgrade filling, vibration frequency, amplitude, and vehicle speed. It demonstrates the influence of the bottom filling material on the continuous detection values ​​of compaction quality. At the same time, the influence of vibration compaction parameters is also quantitatively considered in the continuous compaction quality evaluation model, thus achieving high accuracy in continuous detection.

[0045] This invention collects continuous vibration signals during the compaction process of a road roller, uses modal parameter identification to identify the vibration system, and obtains a system stiffness evaluation index that reflects the compaction state of fine sand subgrade, thereby providing real-time and accurate feedback on compaction quality.

[0046] Based on the real-time feedback of compaction status evaluation results, this invention adjusts the compaction process of the road roller in a timely manner, identifies relatively weak compaction areas, and performs re-compaction after taking other possible measures to avoid over-compaction or under-compaction, thereby improving the quality and efficiency of on-site construction.

[0047] This invention effectively reflects the compaction quality at each point by evaluating the location information and compaction status of each area during the compaction operation of a road roller.

[0048] This invention addresses the lack of physical basis and poor practical results of current intelligent compaction control indicators, effectively overcomes the shortcomings of current detection technologies, and can be flexibly applied to compaction operations in the field of civil engineering. Attached Figure Description

[0049] Figure 1 This is a flowchart of an embodiment of the present invention;

[0050] Figure 2 This is a flowchart of the standard curve training process for the continuous compaction quality detection index model according to an embodiment of the present invention.

[0051] Figure 3 This is a flowchart of the repeated periodic data training process for the continuous compaction quality detection index model according to an embodiment of the present invention. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0053] Currently, by collecting vibration signals from specific locations of the roller during the compaction process, a real-time compaction quality detection method based on indicators such as harmonic ratio, vibration modulus, effective value of acceleration, and foundation reaction force has been proposed. However, these indicators lack certain physical basis, and the understanding of the feedback vibration signals is unclear. As a result, due to the large fluctuation of vibration signals during actual compaction, it is difficult to accurately determine the compaction quality of the roadbed, leading to poor practical application results.

[0054] Methods that enable continuous information monitoring of the roadbed compaction process merely acquire the roller's trajectory and number of passes during compaction, and then analyze the data to determine whether relevant indicators meet specifications. However, this method only provides real-time monitoring of the construction process—i.e., digital (information-based) construction—and is not a strictly intelligent compaction technology; it cannot determine the roadbed compaction quality in real time.

[0055] like Figure 1 As shown, the present invention provides a method for testing the compaction of fine sand roadbed, comprising:

[0056] Acquire detection location information and corresponding vibration signals from multiple detection locations during the compaction operation of the road roller;

[0057] Input the detection location information and the detection vibration signal into the continuous detection index model of compaction quality;

[0058] Among them, the continuous testing index model for compaction quality includes standard curves and repetition cycle data;

[0059] By comparing the detection location information and the detected vibration signal with the standard curve or repetitive period data, the compaction quality test results of each detection location of the roadbed are determined.

[0060] This invention establishes a continuous detection model for subgrade compaction quality, which includes the quality of the bottom subgrade filling, vibration frequency, amplitude, and vehicle speed. It demonstrates the influence of the bottom filling material on the continuous detection values ​​of compaction quality. At the same time, the influence of vibration compaction parameters is also quantitatively considered in the continuous compaction quality evaluation model, thus achieving high accuracy in continuous detection.

[0061] This invention collects continuous vibration signals during the compaction process of a road roller, uses modal parameter identification to identify the vibration system, and obtains a system stiffness evaluation index that reflects the compaction state of fine sand subgrade, thereby providing real-time and accurate feedback on compaction quality.

[0062] Based on the real-time feedback of compaction status evaluation results, this invention adjusts the compaction process of the road roller in a timely manner, identifies relatively weak compaction areas, and performs re-compaction after taking other possible measures to avoid over-compaction or under-compaction, thereby improving the quality and efficiency of on-site construction.

[0063] This invention effectively reflects the compaction quality at each point by evaluating the location information and compaction status of each area during the compaction operation of a road roller.

[0064] This invention addresses the lack of physical basis and poor practical results of current intelligent compaction control indicators, effectively overcomes the shortcomings of current detection technologies, and can be flexibly applied to compaction operations in the field of civil engineering.

[0065] Furthermore, it also includes filtering the detected vibration signal to remove interference signals and obtain a time-domain signal that contains only roadbed vibration information.

[0066] The collected vibration signals contain various signal components, including the natural frequency of the roller engine, the simple harmonic excitation of the steel wheel, the excitation of the roadbed unevenness, and vibration signals related to the roadbed vibration response. By signal filtering, components that are not related to the vibration response signal of the compacted entity are removed.

[0067] Furthermore, signal filtering can be performed using band-stop filters and low-pass filters to filter the engine's natural frequency and the steel wheel's simple harmonic excitation frequency.

[0068] Furthermore, the detection location information is consistent with the acquisition frequency of the vibration signal.

[0069] The vibration signal contains both system excitation components and inherent system properties. Therefore, the vibration response signal needs to be filtered, including filtering the steel wheel harmonic excitation frequency and the engine excitation frequency. After filtering, the response signal only contains components reflecting the inherent system properties and stationary random excitation.

[0070] Furthermore, a fast Fourier transform is performed on the filtered vibration signal to convert it from a time-domain signal to a frequency-domain signal; among which, an overlapping segmented fast Fourier transform is used to achieve continuous detection of compaction.

[0071] Furthermore, the continuous monitoring index model for compaction quality is obtained through the following steps:

[0072] A continuous monitoring index model for compaction quality is constructed by relating the vibration signals obtained from the road roller traveling along a prescribed route within the work site to the compaction quality.

[0073] The continuous monitoring index model for compaction quality was trained.

[0074] Further, such as Figure 2 As shown, training the continuous monitoring index model for compaction quality includes:

[0075] A standard curve was obtained by comparing the difference before and after compaction operations were carried out in a specified area;

[0076] The road roller is made to travel along a prescribed route within the work site, and the real-time position information and real-time vibration signal of the road roller are obtained repeatedly within the repeat cycle.

[0077] The standard curve and repeated real-time position information, along with repeated real-time vibration signals, are input into the continuous compaction quality detection index model.

[0078] When the repeated real-time vibration signal approaches the standard curve, a continuous detection index model for compaction quality is obtained.

[0079] Furthermore, the standard curve obtained by comparing the differences before and after compaction operations within a specified area includes:

[0080] Acquire the first vibration signal of the road roller operating within the designated area;

[0081] Acquire the second vibration signal after the road roller performs compaction operations within a specified area;

[0082] The first and second vibration signals are input into the continuous compaction quality detection index model to obtain the standard curve.

[0083] Furthermore, the first vibration signal and the second vibration signal are a combination of N signals obtained by continuous compaction vibration detection using different vibration frequencies, vehicle speeds and amplitudes, where N is a positive integer.

[0084] Furthermore, when the vibration signals received by the road roller at the same position are nearly identical under the same vibration frequency, vehicle speed, and amplitude, the vibration signal obtained at this time is the second vibration signal.

[0085] Further, such as Figure 3 As shown, training the continuous monitoring index model for compaction quality includes:

[0086] The road roller is made to travel along a prescribed route within the work site, and the first real-time position information and the first real-time vibration signal of the road roller are obtained in the first cycle.

[0087] The first real-time location information and the first real-time vibration signal are input into the continuous compaction quality detection index model as the first cycle data;

[0088] The road roller is made to travel along a prescribed route within the work site, and the real-time position information and real-time vibration signal of the road roller are obtained repeatedly within the repeat cycle.

[0089] The repeated real-time location information and repeated real-time vibration signal are input into the continuous detection index model of compaction quality as repeated cycle data.

[0090] When the difference between the repeated cycle data and the first cycle data is the largest, a continuous compaction quality detection index model is obtained.

[0091] The designated route includes designated areas.

[0092] During compaction, changes in soil properties will alter the system characteristics of the roller-soil vibration system. When the compacted material is under-compacted, as compaction progresses, the compaction degree of the compacted material increases, the stiffness of the roller-soil vibration system increases, and the system's natural frequency increases. When over-compactment is reached, the compaction degree of the compacted material no longer increases, the system stiffness tends to stabilize, and the system's natural frequency no longer increases.

[0093] The current compaction state of the compacted entity can be determined by identifying changes in the system's first-order natural frequency. When the compacted entity is relatively loose, as compaction progresses, the degree of compaction increases, and the system's first-order natural frequency increases. When over-compaction is reached, the degree of compaction no longer increases, and the system's first-order natural frequency also stops increasing. In the later stages of compaction, when the rate of increase in the system's first-order natural frequency between two consecutive compaction passes is less than 1%, the required degree of compaction is considered to have been achieved. This allows for the acquisition of a standard curve and repetition cycle data, leading to a continuous monitoring index model for compaction quality.

[0094] Furthermore, the first real-time location information includes a combination of N location information of the road roller in the first cycle, where N is a positive integer.

[0095] Furthermore, the first real-time vibration signal includes: a combination of N vibration signals corresponding to the position information obtained by continuously detecting compaction vibration with the same vibration frequency, the same vehicle speed and amplitude when the road roller is located at N position information of the first real-time position information, where N is a positive integer.

[0096] This invention provides a system for implementing a method for detecting compaction of fine sand subgrade, comprising:

[0097] The road roller is equipped with an acceleration sensor, an amplitude detection module, an on-board signal analysis and processing module, and an on-board display module;

[0098] An accelerometer is mounted on the vibrating wheel to collect the vertical acceleration signal of the vibrating wheel;

[0099] The amplitude detection module detects the included angle of the eccentric blocks of the road roller and can be used as a vibration signal sensor.

[0100] The vibration signal sensor can be installed on the road roller at the steel wheel, the cab, or other locations. The optimal installation location can be determined through preliminary experiments, ensuring that the response signal containing the resonance peak of the system's first-order natural frequency can be measured.

[0101] The vibration signal sensor can collect vibration signals using either velocity measurement or acceleration measurement. In this embodiment, velocity measurement is preferred, and the sampling frequency of the vibration signal sensor should be no less than 200Hz.

[0102] The frequency range of the system's first natural frequency can be determined by the test section, roughly in the range of 5-20Hz. The engine's natural frequency can be collected when the roller is not moving. The steel wheel's simple harmonic excitation is determined based on the roller's operating frequency.

[0103] The three-dimensional position information, speed information, acceleration signal, and amplitude information of the road roller are all transmitted to the on-board information analysis and processing module;

[0104] The onboard information analysis and processing module detects the instantaneous vibration frequency of the road roller by performing Hilbert-Huang transform on the acceleration signal;

[0105] The on-board display module shows the current location of the road roller, vibration compaction parameters, and areas with acceptable and unacceptable compaction quality in real time.

[0106] The satellite positioning receiving module is used to acquire the detection location information of the detection location during the compaction operation of the road roller;

[0107] The detected location information includes the three-dimensional spatial location information and travel speed information of the road roller.

[0108] Furthermore, the road roller is also equipped with a GPS positioning device.

[0109] The GPS positioning device supports BeiDou, GPS, and GLONASS systems and can accurately obtain the location information of the road roller during operation.

[0110] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for testing the compaction of fine sand subgrade, comprising: Acquire detection location information and corresponding vibration signals at multiple detection locations during the compaction operation of the road roller; The detection location information and the detection vibration signal are input into the continuous detection index model of compaction quality; The continuous compaction quality detection index model includes a standard curve and repetition period data. The detection location information and the detection vibration signal are compared with the standard curve or the repetition period data to determine the compaction quality detection result of each detection location of the roadbed; The continuous compaction quality detection index model is obtained through the following steps: The continuous detection index model for compaction quality is constructed by relating the vibration signals obtained from the road roller traveling along a prescribed route within the work site to the compaction quality. The continuous compaction quality detection index model is trained; The training of the continuous compaction quality detection index model includes: A standard curve was obtained by comparing the difference before and after compaction operations were carried out in a specified area; The road roller is made to travel along a prescribed route within the work site, and the real-time position information and real-time vibration signal of the road roller are obtained repeatedly within the repeat cycle. The standard curve, the repeated real-time position information, and the repeated real-time vibration signal are input into the continuous compaction quality detection index model. When the repetitive real-time vibration signal approaches the standard curve, the continuous detection index model of compaction quality is obtained. The standard curve obtained by comparing the difference before and after compaction operations within a specified area includes: Acquire the first vibration signal of the road roller operating within the specified area; Acquire the second vibration signal after the road roller performs compaction operations within the specified area; The first vibration signal and the second vibration signal are input into the continuous compaction quality detection index model to obtain the standard curve.

2. The method according to claim 1, characterized in that, The first vibration signal and the second vibration signal are a combination of N signals obtained by continuous compaction vibration detection using different vibration frequencies, vehicle speeds and amplitudes, where N is a positive integer.

3. The method according to claim 1, characterized in that, When the vibration signals received by the road roller at the same position are nearly identical under the same vibration frequency, vehicle speed and amplitude, the vibration signal obtained at this time is the second vibration signal.

4. The method according to claim 1, characterized in that, The training of the continuous compaction quality detection index model includes: The road roller is made to travel along a prescribed route within the work site, and the first real-time position information and the first real-time vibration signal of the road roller are obtained in the first cycle. The first real-time location information and the first real-time vibration signal are input into the continuous compaction quality detection index model as the first cycle data. The road roller is made to travel along a prescribed route within the work site, and the real-time position information and real-time vibration signal of the road roller are obtained repeatedly within the repeat cycle. The repeated real-time location information and the repeated real-time vibration signal are input into the continuous compaction quality detection index model as repeated cycle data. When the difference between the repeated period data and the first period data is the largest, the continuous compaction quality detection index model is obtained. The specified route includes the specified area.

5. The method according to claim 4, characterized in that, The first real-time location information includes a combination of N location information of the road roller in the first cycle, where N is a positive integer.

6. The method according to claim 4, characterized in that, The first real-time vibration signal includes: a combination of N vibration signals corresponding to the position information obtained by continuously detecting compaction vibration with the same vibration frequency, the same vehicle speed and amplitude when the road roller is located at N position information of the first real-time position information, where N is a positive integer.

7. A system for implementing the compaction testing method for fine sand subgrade according to any one of claims 1-6, characterized in that, include: The road roller is equipped with an acceleration sensor, an amplitude detection module, an on-board signal analysis and processing module, and an on-board display module; The acceleration sensor is mounted on the vibrating wheel to collect the vertical acceleration signal of the vibrating wheel; The amplitude detection module detects the included angle of the eccentric blocks of the road roller; The three-dimensional position information, speed information, acceleration signal, and amplitude information of the road roller are all transmitted to the on-board information analysis and processing module; The onboard information analysis and processing module detects the instantaneous vibration frequency of the road roller by performing Hilbert-Huang transform on the acceleration signal; The vehicle-mounted display module displays the current location of the road roller, vibration compaction parameters, and areas with acceptable and unacceptable compaction quality in real time. The satellite positioning receiving module is used to acquire the detection position information of the detection position during the compaction operation of the road roller; The detected location information includes the three-dimensional spatial location information and travel speed information of the road roller.

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