JP7724096B2 - Quality control system and quality control method - Google Patents

Description

This disclosure relates to a quality control system and a quality control method, and in particular to technology suitable for quality control of the compaction state of ground in earthworks.

In general, earthworks such as road embankments, fill dams, river levees, and residential land development involve compaction using vibratory rollers, and quality control to evaluate the state of ground compaction is important. Conventional quality control methods for earthworks include measuring wet density using the sand displacement method or water displacement method, measuring moisture content using the oven drying method or RI method, and measuring ground stiffness using plate loading tests (see, for example, Patent Documents 1 and 2).

Japanese Patent Application Laid-Open No. 2005-146692 Japanese Patent Application Laid-Open No. 2007-010568

All of the above conventional measurement methods have the drawback that they are only capable of post-construction measurements, and that it takes time for measurement results to be obtained. As a result, by the time insufficient compaction is discovered, construction has often already progressed to a certain extent, posing the issue of requiring significant rework and rework if any follow-up measures are to be taken in areas where compaction is insufficient. Furthermore, all of the above conventional measurement methods are discrete measurements, and are unable to measure the entire construction surface at multiple points or across a surface, which means that construction quality cannot be evaluated with a high degree of accuracy.

This disclosure was made in light of the above circumstances, and aims to improve the accuracy of quality control in earthworks by evaluating the ground compaction condition across the entire construction surface.

The quality control system of the present disclosure includes:
an acceleration acquiring means for acquiring vibration acceleration of a vibrating roller that compacts the ground by transmitting vibration to the ground;
a position information acquisition means capable of acquiring position information of the vibration compactor;
a rolling number calculation means for dividing the surface of the ground into a plurality of areas and calculating the number of times each of the areas has been rolled by the vibrating rolling machine based on the position information acquired by the position information acquisition means;
a compaction index value calculation means for calculating an index value indicating the compaction state of the ground compacted by the vibrating roller for each of the plurality of regions by performing frequency analysis on the vibration acceleration acquired by the acceleration acquisition means;
a database that stores the index value calculated by the compaction index value calculation means in association with the number of times of compaction for each of the plurality of regions;
The present invention is characterized by comprising an output processing means capable of outputting the number of times of compaction and the index value stored in the database for each of the plurality of regions.

Another aspect of the quality control system of the present disclosure is:
The method further includes a subsidence amount acquisition means capable of acquiring a subsidence amount, which is a vertical displacement amount of the ground compacted by the vibrating compactor, for at least each of the plurality of regions,
The database stores the subsidence amount acquired by the subsidence amount acquisition means in association with the number of times of compaction for each of the plurality of regions,
It is preferable that the output processing means is capable of outputting the subsidence amount stored in the database for each of the plurality of regions.

Another aspect of the quality control system of the present disclosure is:
It is preferable to further provide a compaction determination means for determining whether the ground has been compacted based on the convergence tendency of the index value calculated by the compaction index value calculation means and/or the convergence tendency of the subsidence amount acquired by the subsidence amount acquisition means.

Another aspect of the quality control system of the present disclosure is:
The apparatus further includes a moisture content acquisition means capable of acquiring the moisture content of the ground compacted by the vibrating roller for at least each of the plurality of regions,
The database stores the moisture content acquired by the moisture content acquisition means in association with the number of times of compaction for each of the plurality of regions,
It is preferable that the output processing means is capable of outputting the water content ratio stored in the database for each of the plurality of regions.

Another aspect of the quality control system of the present disclosure is:
It is preferable to further include a material change determination means for determining whether or not the soil material has changed for each of the plurality of regions based on the change in the water content acquired by the water content acquisition means.

Another aspect of the quality control system of the present disclosure is:
The moisture content acquisition means is preferably mounted on a mobile body that can travel autonomously or follow the travel path of the vibrating roller.

In another aspect of the quality control system of the present disclosure,
The compaction index value calculation means
If the transmission depth of the vibration force of the vibrating roller is deeper than the thickness of the construction layer that can be compacted in one compaction operation, it is preferable to perform a correction process to remove the influence of the lower layer when calculating the index value of the current construction layer.

In another aspect of the quality control system of the present disclosure,
The compaction index value calculation means
It is preferable to use a first predetermined number of vibration acceleration data as the processing unit required for one frequency analysis, and each time a second predetermined number of vibration acceleration data that is smaller than the processing unit is acquired, perform frequency analysis using the vibration acceleration data of the processing unit that includes the second predetermined number of vibration acceleration data most recently acquired, thereby executing a shift process that makes the calculation period of the index value shorter than the sampling period of the vibration acceleration data.

In another aspect of the quality control system of the present disclosure,
The compaction index value calculation means preferably calculates, as the index value, an acceleration response value obtained by the frequency analysis and a ground deformation coefficient obtained from the acceleration response value.

The quality control method of the present disclosure includes:
A rolling compaction work is carried out to compact the ground using a vibrating rolling machine that transmits vibrations to the ground,
Acquire position information of the vibrating roller in parallel with the rolling compaction,
The ground is divided into a plurality of areas, and the number of times each of the areas is compacted by the vibrating compactor is calculated based on the position information;
acquiring the vibration acceleration of the vibrating roller and performing frequency analysis on the acquired vibration acceleration, thereby calculating an index value indicating the compaction state of the ground compacted by the vibrating roller for each of the plurality of regions;
constructing a database that stores the index values calculated for each of the plurality of regions in association with the number of times of compaction;
The number of times of compaction and the index value stored in the database are output for each of the plurality of regions.

The quality control system and quality control method disclosed herein enable the accuracy of quality control to be improved by evaluating the compaction condition of the ground across the entire construction surface in earthworks.

1 is a schematic functional block diagram showing a quality control system according to an embodiment of the present invention; 1 is a schematic diagram showing an example of a site to which a quality control system according to an embodiment of the present invention is applied, and a vibrating roller; FIG. 10 is a schematic diagram showing an example of a rolling compaction count map according to the present embodiment. 4 is a graph schematically showing an acceleration waveform of a vibrating roller and the results of frequency analysis of the acceleration waveform. 10 is a time chart illustrating a specific example of shift processing in frequency analysis according to the present embodiment. FIG. 1 is a conceptual diagram illustrating a two-layer structure model used for two-layer ground correction according to this embodiment. FIG. 2 is a schematic diagram illustrating the overall configuration of a subsidence amount acquisition unit according to the present embodiment. FIG. 2 is a schematic diagram illustrating the overall configuration of a water content acquisition unit according to the present embodiment. FIG. 1 is a schematic diagram for explaining an example of an outline of a multidimensional database according to an embodiment of the present invention. 1 is a flowchart illustrating a quality control method according to the present embodiment.

The quality control system and quality control method according to this embodiment will be described below with reference to the accompanying drawings. Identical components are designated by the same reference numerals, and their names and functions are also the same. Therefore, detailed descriptions of these components will not be repeated.

[Quality Control System]
Fig. 1 is a schematic functional block diagram showing a quality control system 1 according to this embodiment, and Fig. 2 is a schematic diagram showing an example of a site to which the quality control system 1 according to this embodiment is applied, and a vibrating roller 2. Note that, hereinafter, the quality control system 1 may also be simply referred to as "the present implementation device."

As shown in FIG. 1, the quality control system 1 includes a compaction count/acceleration analysis unit 10, a subsidence acquisition unit 20 (subsidence acquisition means), a moisture content acquisition unit 30 (moisture content acquisition means), a quality control processing unit 40, a display unit 50, and an input unit 60. In this implementation device, the compaction count/acceleration analysis unit 10 is mounted on a vibrating roller 2 (see FIG. 2) that compacts the ground at the construction site. The quality control processing unit 40 is, for example, configured as an information processing device such as a personal computer or server installed in the management office 8 (see FIG. 2), and is communicatively connected to each of the compaction count/acceleration analysis unit 10, subsidence acquisition unit 20, moisture content acquisition unit 30, display unit 50, and input unit 60. The management office 8 may be located on the construction site or may be located remotely from the construction site.

The compaction count/acceleration analysis unit 10 includes a position information acquisition device 11 (position information acquisition means), an acceleration sensor 12 (acceleration acquisition means), and a calculation processing unit 13. The position information acquisition device 11, acceleration sensor 12, and calculation processing unit 13 are connected to each other so that they can communicate via wired or wireless communication. In addition, the calculation processing unit 13 is connected to an on-board display 18 and an input device 19, which are provided in the driver's cab 7 of the vibrating roller 2, etc.

The position information acquisition unit 11 is, for example, a GNSS (Global Navigation Satellite System) that acquires position information of the vibrating roller 2 by receiving signals from multiple positioning satellites via an antenna 11A. Note that the position information acquisition unit 11 may also use a satellite positioning system other than GNSS, such as a GPS (Global Positioning System). The position information of the vibrating roller 2 acquired by the position information acquisition unit 11 is transmitted to the calculation processing unit 13 and sequentially stored in the memory unit of the calculation processing unit 13.

The acceleration sensor 12 is attached to the vibratory roller 2 and detects the vibration acceleration of the vibratory roller 2 in the vertical direction. The general configuration of the vibratory roller 2 will now be described with reference to Figure 2 (B). The vibratory roller 2 (an example of a vibratory compactor) comprises a vehicle body 4 with drive wheels 3, a roller wheel 5 equipped with an excitation device (not shown), a support frame 6 that supports the roller wheel 5, and a driver's cab 7 attached to the vehicle body 4. The roller wheel 5 is made of, for example, steel, and compacts the ground by vibrating in the vertical direction due to the excitation force transmitted from the excitation device.

In this embodiment, the acceleration sensor 12 is attached, for example, to the non-damping portion of the roller wheel 5 (support frame 6 in the illustrated example) and is capable of detecting the vertical acceleration of the roller wheel 5 (hereinafter simply referred to as vibration acceleration A). The vibration acceleration A acquired by the acceleration sensor 12 is transmitted to the calculation processing unit 13 and sequentially stored in the memory unit of the calculation processing unit 13.

Returning to Figure 1, the calculation processing unit 13 includes a processing unit such as a CPU, storage units such as RAM and ROM, an input/output interface, an auxiliary storage device, etc., and is configured using an information processing device such as a personal computer. By having the CPU execute an analysis program stored in the ROM, the calculation processing unit 13 functions as a device including a compaction count calculation unit 14 (compaction count calculation means), an acceleration response value calculation unit 15 (compaction index value calculation means), a ground deformation coefficient calculation unit 16 (compaction index value calculation means), and a two-layer correction processing unit 17.

In this embodiment, the calculation processing unit 13 is provided on the vibrating roller 2 side, but like the quality control processing unit 40, the calculation processing unit 13 can also be provided on the information processing device on the management office 8 side. In this case, the calculation processing unit 13 simply needs to be connected to both the position information acquisition device 11 and the acceleration sensor 12 so that they can communicate wirelessly.

[Number of compactions]
The rolling number calculation unit 14 calculates the number of times Rn that the vibrating roller 2 has rolled the ground G as a construction target, based on the position information (traveling trajectory) of the vibrating roller 2 acquired by the position information acquisition unit 11. Specifically, as shown in Fig. 2(A), the rolling number calculation unit 14 divides the ground G (surface) as a construction target at the site into a mesh-like pattern, for example, into a plurality of 1 m square regions G1, G2, ... Gn, and calculates the number of times Rn of rolling for each region G1, G2, ... Gn. When the rolling count calculation unit 14 detects that the vibrating roller 2 has passed through (or entered) a specific area (for example, area G1) once based on the position information of the vibrating roller 2 acquired by the position information acquisition unit 11, it counts the number of rollings Rn of the area (area G1) as one, and thereafter calculates the number of rollings Rn of the area (area G1) by sequentially adding the number of times each time the vibrating roller 2 passes through (or enters) the area (area G1). The rolling counts Rn calculated by the rolling count calculation unit 14 are linked to each of the areas G1, G2, ... Gn, stored in the memory of the calculation processing unit 13, and also transmitted to the quality control processing unit 40 in real time.

Figure 3 shows an example of a rolling count map M (heat map) created based on the rolling count Rn calculated by the rolling count calculation unit 14. As shown in Figure 3, the rolling count map M displays the number of rollings Rn performed by the vibrating roller 2 for each of multiple regions G1, G2, ... Gn so that it can be visually grasped. The number of rollings Rn for regions G1, G2, ... Gn may be displayed in a darker color the greater the number of rollings Rn, as in the illustrated example. Alternatively, the specific number of rollings Rn (numerical value) may be displayed for each region G1, G2, ... Gn. The rolling count map M may be displayed on the on-board display 18 installed in the driver's cab 7 of the vibrating roller 2, or on the display unit 50 at the management office 8. In this way, by displaying the compaction count map M, which shows the number of compactions Rn by the vibrating roller 2 for each region G1, G2...Gn, in real time, it becomes possible to grasp the areas in the construction target ground G that have been sufficiently compacted and the areas that have not been sufficiently compacted while construction is underway, thereby improving construction quality.

[Acceleration response value]
The acceleration response value calculation unit 15 calculates the acceleration response value Ft (the rate of fluctuation in acceleration data that increases as the ground is compacted) based on the vibration acceleration A acquired by the acceleration sensor 12. Here, the vibrating roller 2 compacts the target ground G by vibrating the roller wheels 5 in the vertical direction using a vibration excitation device. The acceleration waveform of the roller wheels 5 when compacting the ground becomes more distorted as the ground stiffness increases with ground compaction, and high-frequency components become prominent as a spectrum (see Figure 4). The acceleration response value calculation unit 15 calculates the acceleration response value Ft at a predetermined calculation period using a so-called vibration acceleration response method that focuses on this property.

Specifically, the acceleration response value calculation unit 15 performs a fast Fourier transform (hereinafter referred to as FFT analysis) on the signal from the acceleration sensor 12 to obtain a harmonic spectrum Si and a 1/2 subharmonic spectrum Si′, and calculates the acceleration response value Ft based on the following equation (1).
In formula (1), Si is the harmonic spectrum, Si' is the 1/2 subharmonic spectrum, _S0 is the fundamental frequency spectrum, _S0 ' is the 1/2 fundamental frequency spectrum, F is the vibratory force of the vibratory roller 2, m1 is the mass of the support frame 6, and m2 is the mass of the roller compaction wheel 5. The vibratory force F, mass m1, and mass m2 may be values listed in a specification table or the like for the vibratory roller 2, and may be input by the operator by operating the input device 19 or input unit 60. The acceleration response value Ft for each region G1, G2, ... Gn calculated by the acceleration response value calculation unit 15 is transmitted to the ground deformation coefficient calculation unit 16 and the quality control processing unit 40.

[Shift processing]
Here, since FFT analysis calculates the frequency components of input data, a certain number of data (e.g., 1024) is required to maintain resolution. In FFT analysis processing, if the required number of data is acquired at a high sampling rate, wideband analysis can be achieved, but if the sampling rate is increased too much, the load on the CPU increases. For this reason, it is desirable to lower the sampling rate to a certain extent so as not to affect the processing capacity of the CPU. However, since it takes time to gather the number of data required for FFT analysis, there is a problem in that it takes a long time to output the calculation results.

With this in mind, the present implementation device acquires 1024 pieces of data (first predetermined number) per second, and uses the 1024 pieces of data as the processing unit required for FFT analysis. Each time 512 pieces of data (second predetermined number), half the processing unit, are acquired, a "shift process" is performed to perform FFT analysis using the most recent 1024 pieces of data. A specific example of the shift process is described below based on the time chart in Figure 5.

As shown in Figure 5, the nth FFT analysis is performed at time t0, when 1,024 pieces of data have been acquired. Next, the n+1th FFT analysis is performed at time t1, 0.5 seconds after time t0, when 512 pieces of data, half the processing unit, have been acquired. At this time, the FFT analysis is performed by shifting half of the data to be processed to the previous data (the data used in the nth FFT analysis), thereby ensuring the number of data required for the FFT analysis. Similarly, the n+2th and subsequent FFT analyses are performed by shifting half of the data to be processed to the previous data, with the calculation results being output sequentially every 0.5 seconds.

In other words, by performing a shift process that shifts half of the data to be processed to the most recent data, the system is configured to ensure the number of data points required for FFT analysis while outputting calculation results at a cycle shorter than the sampling period. This effectively improves the responsiveness of the calculation process without reducing the resolution during FFT analysis.

The processing unit for FFT analysis is not limited to 1024, and can be set to an appropriate value depending on the CPU capabilities and RAM capacity of the calculation processing unit 13, the performance of the acceleration sensor 12, etc. Also, while the shift process shifts half of the processing target, the shift amount can also be set to a value greater than half or less than half depending on the target sampling period and calculation period.

[Ground deformation coefficient]
1 again, the ground deformation coefficient calculation unit 16 calculates the ground deformation coefficient E (ground rigidity) based on the relational expression between the acceleration response value and the ground deformation coefficient obtained in advance by an experiment, etc. Specifically, the ground deformation coefficient calculation unit 16 calculates the ground deformation coefficient E by substituting the acceleration response value Ft calculated by the acceleration response value calculation unit 15 and the specification values of the vibrating roller 2 into the following mathematical formula (2).
In equation (2), F is the excitation force of the vibrating roller 2, m1 is the mass of the support frame 6, m2 is the mass of the roller wheel 5, f0 is the vibration frequency, B is the width of the roller wheel 5, and v is the Poisson's ratio.

In this embodiment, the acceleration response value Ft and ground deformation coefficient E are linked to the position information of the vibrating roller 2 acquired by the position information acquisition unit 11 and stored in the memory unit of the calculation processing unit 13. That is, similar to the above-described compaction count map M (see Figure 3), the acceleration response value Ft and ground deformation coefficient E corresponding to each region G1, G2, ... Gn can be displayed as a heat map. For example, the heat map may display a darker color for regions with larger acceleration response values Ft, or specific numerical values of the acceleration response value Ft and ground deformation coefficient E for each region G1, G2, ... Gn. Displaying the heat map of the acceleration response value Ft and ground deformation coefficient E created in this way together with the compaction count map M allows the compaction state of the ground and the number of compactions Rn for each region G1, G2, ... Gn to be easily grasped in real time.

[Two-layer ground correction]
In general earthworks, ground compaction is carried out in stages over multiple layers, and each layer is compacted to a thickness of approximately 30 cm for construction management reasons. On the other hand, vibratory rollers 2 are often high-performance, and the vibrations transmitted to the ground from the roller wheels 5 are transmitted to layers below the layer currently being compacted (hereinafter referred to as the current construction layer).

After conducting a variety of experiments and simulations, the inventors discovered that the acceleration response value Ft and ground deformation coefficient E obtained using the vibration acceleration response method are average values for the range from the ground surface of the current construction layer to a depth of approximately 60 cm. In other words, as shown in Figure 6, the inventors discovered that by modeling the on-site ground as a two-layer structure consisting of an upper current construction layer L1 and a lower layer L2 directly below it, and eliminating the influence of the lower layer L2 when calculating the acceleration response value Ft and ground deformation coefficient E of the current construction layer L1, the ground rigidity of the current construction layer L1 can be calculated with high accuracy.

From this perspective, the calculation processing unit 13 of this implementation device is equipped with a two-layer correction processing unit 17 for performing correction processing to eliminate the influence of the lower layer L2 when calculating the acceleration response value Ft and ground deformation coefficient E of the current construction layer L1. The specific correction processing method may be based on a model formula that takes into account the acceleration response values, ground deformation coefficient, Poisson's ratio, and vibration stress transmission angle of the current construction layer L1 and the lower layer L2, or it may be performed by referencing a lookup table created in advance through experiments. The acceleration response value and ground deformation coefficient of the lower layer L2 can be obtained by reading data calculated by the calculation processing unit 13 during compaction of the lower layer L2 and then performing compaction of the current construction layer L1. In this way, performing two-layer correction processing to eliminate the influence of the layer immediately below enables highly accurate calculation of the acceleration response value Ft and ground deformation coefficient E of the current construction layer L1. Note that while the implementation device has been described using a two-layer structure model as an example, correction processing may also be performed using a three- or more-layer structure model if the vibratory roller 2 has higher performance.

[Subsidence measurement]
The subsidence amount acquisition unit 20 includes a laser scanner 21 as a surveying instrument. Specifically, as shown in Fig. 7 , the laser scanner 21 includes a laser sensor unit 22 that emits laser light and receives reflected light, a support unit 23 that supports the laser sensor unit 22, and a tripod 24 to which the support unit 23 is attached at its upper part. The laser scanner 21 is configured so that the three-dimensional coordinates (x, y, z) of a measurement point on the ground surface can be measured by the support unit 23 rotating the laser sensor unit 22 in a direction horizontal to the ground surface and in a direction vertical to the ground surface.

In this embodiment, the laser scanner 21 defines the travel path of the vibrating roller 2 acquired by the position information acquisition unit 11 as a measurement line L, and by scanning laser light along this measurement line L, acquires the three-dimensional coordinates of multiple measurement points Pz1, Pz2, ... Pzn defined on the measurement line L as point cloud data.

Here, measurements by the laser scanner 21 are performed during the period from when the vibrating roller 2 compacts the ground to when the ground is next compacted. That is, point cloud data for each measurement point Pz1, Pz2...Pzn is acquired each time the vibrating roller 2 compacts the ground. This makes it possible to grasp the vertical displacement (subsidence) corresponding to the number of compactions Rn for each measurement point Pz1, Pz2...Pzn in parallel with the compaction work. There must be at least one measurement point Pz1, Pz2...Pzn for each area G1, G2...Gn, and there may be multiple measurement points for each area G1, G2...Gn. The point cloud data for each measurement point Pz1, Pz2...Pzn measured by the laser scanner 21 is transmitted to the quality control processing unit 40 and stored in the memory of the quality control processing unit 40, linked to the number of compactions Rn for each area G1, G2...Gn.

[Water content measurement]
The moisture content acquisition unit 30 is equipped with a scattering-type RI moisture density meter 31 as a measuring instrument. Specifically, as shown in Fig. 8, the moisture content acquisition unit 30 has a traveling body 33 equipped with the RI moisture density meter 31. The traveling body 33 is also equipped with a GNSS 32 as a position information acquisition device.

The running body 33 is equipped with a plurality of wheels 34. The plurality of wheels 34 includes drive wheels and steered wheels. The running body 33 is also equipped with a running motor that transmits power to the drive wheels, a steering motor that steers the steered wheels, and a battery that supplies power to these motors. In this embodiment, the running body 33 is configured to run along the running trajectory of the vibrating roller 2. The running method of the running body 33 may be either an autonomous running type that automatically runs along a target trajectory set based on the running trajectory of the vibrating roller 2, or a follow-up running type that runs by following the vibrating roller 2.

The RI moisture density meter 31 primarily comprises a radiation source 31A that emits radiation into the ground and a detector 31B that detects radiation that enters and scatters in the ground, and measures the moisture density and wet density of the ground. The RI moisture density meter 31 also determines the dry density from the measured moisture density and wet density, and obtains the moisture content w of the measured ground by calculating the ratio of the dry density to the moisture density.

In this implementation device, the moisture content acquisition unit 30 performs measurements using the RI moisture density meter 31 at predetermined measurement points Pw1, Pw2, ... Pwn while running the running body 33 along the running path of the vibrating roller 2. Specifically, measurements using the RI moisture density meter 31 are performed during the period from when the vibrating roller 2 compacts the ground to when the ground is next compacted. In other words, the moisture content w is acquired at each measurement point Pw1, Pw2, ... Pwn each time the ground is compacted by the vibrating roller 2. This makes it possible to understand changes in the moisture content w at each measurement point Pw1, Pw2, ... Pwn according to the number of compactions n performed, in parallel with construction work.

There must be at least one measurement point Pw1, Pw2, ... Pwn for each region G1, G2, ... Gn, and there may be multiple measurement points for each region G1, G2, ... Gn. The moisture content w of each measurement point Pw1, Pw2, ... Pwn obtained by the RI moisture density meter 31 is transmitted to the quality control processing unit 40 and stored in the memory of the quality control processing unit 40, linked to the number of compactions n for each region G1, G2, ... Gn.

[Quality control processing]
1 , the quality control processing unit 40 is equipped with a processing unit such as a CPU, a storage unit such as RAM or ROM, an input/output interface, an auxiliary storage device, etc., and is configured as an information processing device such as a personal computer or a server. By the CPU executing a quality control program stored in the ROM, the quality control processing unit 40 functions as a device equipped with a convergence determination unit 41 (compaction determination means), a material change determination unit 42 (material change determination means), a data input processing unit 43, a multidimensional database 44, and a data output processing unit 45 (output processing means). The quality control processing unit 40 is also connected to a display unit 50 such as a display, and an input unit 60 such as a keyboard and a mouse.

The convergence determination unit 41 determines whether the ground has been sufficiently compacted based on the acceleration response value Ft, the ground deformation coefficient E, and the vertical displacement of the ground obtained from the point cloud data (hereinafter referred to as the subsidence amount Z) of each of the regions G1, G2, ... Gn, from the convergence tendency of this information. Specifically, each time each of the regions G1, G2, ... Gn is compacted by the vibrating roller 2, the convergence determination unit 41 calculates the change ΔFt in the acceleration response value Ft, the change ΔE in the ground deformation coefficient E, and the change ΔZ in the subsidence amount Z in each of the regions G1, G2, ... Gn. Here, each change amount (ΔFt, ΔE, ΔZ) can be calculated by subtracting the values (ΔFt _{n -1} , ΔE _n-1 , ΔZ _n- 1) obtained during the previous compaction from the values (ΔFt _n , ΔE n, ΔZ _n ) obtained during the current compaction.

The convergence determination unit 41 determines that the ground in the relevant region G1, G2, ... Gn is sufficiently compacted when all of the following convergence conditions are met: a first convergence condition that the absolute value of the change in acceleration response value Ft, ΔFt, is equal to or less than a predetermined acceleration response threshold Fv; a second convergence condition that the absolute value of the change in ground deformation coefficient E, ΔE, is equal to or less than a predetermined deformation coefficient threshold Ev; and a third convergence condition that the absolute value of the change in subsidence Z, ΔZ, is equal to or less than a predetermined subsidence threshold Zv. On the other hand, if any of the first to third convergence conditions is not met, the convergence determination unit 41 determines that the ground in the relevant region G1, G2, ... Gn is insufficiently compacted. Note that the determination does not necessarily have to be based on all three of the first to third convergence conditions; any one or two of these three conditions may be used. The convergence conditions to be used should be selected based on the soil materials and ground conditions at the construction site.

The results of the assessment by the convergence assessment unit 41 can be displayed for each region G1, G2...Gn, similar to the compaction count map M shown in Figure 3 above. The assessment results may be displayed in text, or different colors may be used to indicate areas with sufficient compaction and areas with insufficient compaction. In this way, by displaying the assessment results based on the convergence tendency for each region G1, G2...Gn on the map, it becomes possible to grasp areas with sufficient compaction and areas with insufficient compaction for each region G1, G2...Gn while construction is underway, thereby improving construction quality.

The material change determination unit 42 determines whether the soil material at the construction site (e.g., soil grain size, dry density, etc.) has changed based on the moisture content w transmitted from the moisture content acquisition unit 30. In earthworks, ground compaction is carried out in stages across multiple layers. As a result, it is possible that the soil material spread and compacted in the upper layer is different from the soil material used in the lower layer. Each soil material has an optimal moisture content at which it is most compacted, and it is desirable to manage construction near the optimal moisture content when compacting the ground (e.g., within a specified moisture content range including the optimal moisture content).

The material change determination unit 42 acquires the moisture content w of each region G1, G2, ... Gn each time the vibrating roller 2 compacts each of these regions, and if the acquired moisture content w is not within a predetermined moisture content range, determines that the soil material of the corresponding region G1, G2, ... Gn has changed. The predetermined moisture content range may be set based on the soil material selected depending on the site use (road embankment, river levee, etc.) and ground conditions. The determination of material change may also be made by comparing the moisture content _Wn acquired during the current compaction with the moisture content wn _-1 acquired during the previous compaction, and determining that the soil material has changed if the difference between these values is equal to or greater than a predetermined value.

The results of the determination by the material change determination unit 42 can be displayed for each region G1, G2...Gn, similar to the compaction count map M shown in Figure 3 above. The determination results may be displayed in text, or different colors may be used to indicate regions where the soil material has changed and regions where it has not. In this way, by displaying the material change determination results for each region G1, G2...Gn on the map, it becomes easy to identify regions that have been compacted with different soil materials, and it becomes possible to improve construction quality by adjusting the moisture content of those regions, etc.

The data input processing unit 43 stores the number of compactions Rn, acceleration response value Ft, and ground deformation coefficient E transmitted from the compaction count/acceleration analysis unit 10, the amount of subsidence Z calculated based on the point cloud data transmitted from the subsidence amount acquisition unit 20, and the moisture content w transmitted from the moisture content acquisition unit 30 in a multidimensional database 44.

Figure 9 is a schematic diagram illustrating an example of the multidimensional database 44. The multidimensional database 44 is constructed using, for example, data such as "number of compactions Rn" and "area Gn" as dimensions (hierarchies), and data such as "acceleration response value Ft," "ground deformation coefficient E," "subsidence amount Z," and "moisture content w" as measures. By using the slicing function of the multidimensional database 44 to slice the data at a cross section of the hierarchy, it is possible to read out the acceleration response value Ft, ground deformation coefficient E, subsidence amount Z, and moisture content w corresponding to the number of compactions Rn for each area G.

In response to the operator's operation of the input unit 60, the data output processing unit 45 displays data read from the multidimensional database 44 on the display unit 50, or outputs it as a report (document) from a printer (not shown). For example, when a specific area G or number of compactions Rn is specified from the input unit 60, the data output processing unit 45 outputs the acceleration response value Ft, ground deformation coefficient E, settlement amount Z, and water content w for each number of compactions Rn for the specified area G. This allows the operator to quickly and easily grasp the compaction and compaction conditions in each area of the construction site, enabling improved quality control.

[Quality control method]
Next, a quality control method using this implementation device will be described based on the flow shown in Figure 10. Each of the steps S100 to S150 described below is repeatedly executed for each construction layer until the embankment reaches the desired design height.

In step S100, the fill material of the current construction layer Ln is spread evenly and compacted using the vibrating roller 2, and the number of compactions Rn for each area Gn is counted.

In step S110, the acceleration response value Ft and ground deformation coefficient E for each region Gn are calculated in parallel with the rolling by the vibrating roller 2. Note that, for the sake of convenience, steps S100 and S110 are described as two steps, but these processes can be performed substantially simultaneously.

In step S120, the amount of subsidence Z of each area Gn compacted by the vibrating roller 2 is measured, and the moisture content w of each area Gn is also measured. The measurement of the amount of subsidence Z and the moisture content w can be performed in any order, and they can also be performed substantially simultaneously.

Next, in step S130, a material change determination, a convergence determination, and an evaluation of the rolling and compaction conditions using the multidimensional database 44 are performed. If, as a result of these determinations and evaluations, it is determined in step S140 that there are no areas of insufficient rolling (or material changes) in the current construction layer Ln, the process proceeds to step S150, where construction of the current construction layer Ln is terminated and rolling construction of the next construction layer Ln+1 is commenced.

On the other hand, if step S140 determines that there are areas of insufficient compaction in the current construction layer Ln, proceed to step S145, where the areas of the current construction layer Ln that are insufficiently compacted are re-compacted. After re-compaction, steps S110 to S130 are performed again. If step S140 determines that there are no more areas of insufficient compaction, proceed to step S150, where construction of the current construction layer Ln is terminated and compaction of the next construction layer Ln+1 begins. Thereafter, steps S100 to S150 described above are repeatedly performed until the embankment reaches the desired design height.

With the device described above, when compacting the ground G using the vibrating roller 2, the surface of the ground to be compacted is divided into multiple regions G1, G2, ... Gn, and the vibration acceleration A is frequency-analyzed in each region G1, G2, ... Gn to calculate index values (acceleration response value Ft, ground deformation coefficient E) that indicate the compaction state of the ground. Furthermore, a database 44 is constructed that stores the number of compactions Rn of the vibrating roller 2 and the index values (acceleration response value Ft, ground deformation coefficient E) linked to each region G1, G2, ... Gn, and the number of compactions Rn and the index values (acceleration response value Ft, ground deformation coefficient E) stored in the database 44 can be output to a display unit 50 or the like for each region G1, G2, ... Gn. This makes it possible to evaluate the compaction state of the vibrating roller 2 at multiple points or across a surface while compaction is being carried out, thereby improving the accuracy of quality control.

The system is also configured to scan the laser scanner 21 along the travel path of the vibrating roller 2 and acquire the three-dimensional coordinates of each area G1, G2...Gn compacted by the vibrating roller 2 as point cloud data, thereby enabling the amount of subsidence Z of each area G1, G2...Gn to be acquired. This makes it possible to evaluate the convergence trend of the amount of subsidence Z of each area G1, G2...Gn at multiple points or across a surface, while the compaction work is being carried out.

In addition, this device is configured so that a scattering-type RI moisture density meter 31 is mounted on a running body 33 that can run along the running path of the vibrating roller 2, and the moisture content w of each area G1, G2...Gn compacted by the vibrating roller 2 is measured using the RI moisture density meter 31, thereby making it possible to determine changes in the soil material of the construction layer from changes in the measured moisture content w. This makes it possible to grasp changes in the soil material at multiple points or across the entire construction surface while compaction is being carried out, thereby improving construction quality.

[others]
The present disclosure is not limited to the above-described embodiments, and can be appropriately modified and implemented within the scope of the present disclosure.

For example, in the above embodiment, the multidimensional database 44 was described as storing the acceleration response value Ft, ground deformation coefficient E, settlement Z, and moisture content w as measures, but it may also be configured to store the moisture density and wet density measured by the RI moisture density meter 31, and the dry density calculated from these. Furthermore, while this disclosure has been described using the vibrating roller 2 as an example of a vibrating compactor, it can also be widely applied to other heavy machinery capable of transmitting vibrations to the ground to compact it.

1...Quality control system, 2...Vibration roller (vibration compactor), 5...Compaction wheel, 8...Administrative office, 10...Compaction count/acceleration analysis unit, 11...Position information acquisition device (position information acquisition means), 12...Acceleration sensor (acceleration acquisition means), 13...Calculation processing device, 14...Compaction count calculation unit (compaction count calculation means), 15...Acceleration response value calculation unit (compaction index value calculation means), 16...Ground deformation coefficient calculation unit (compaction index value calculation means) 17... Two-layer correction processing unit, 18... On-board display, 19... Input device, 20... Subsidence amount acquisition unit, 21... Laser scanner, 30... Moisture content acquisition unit, 31... RI moisture density meter, 33... Traveling body, 40... Quality control processing unit, 41... Convergence determination unit (compaction determination means), 42... Material change determination unit (material change determination means), 43... Data input processing unit, 44... Multidimensional database, 45... Data output processing unit (output processing means)

Claims (9)

an acceleration acquiring means for acquiring vibration acceleration of a vibrating roller that compacts the ground by transmitting vibration to the ground;
a position information acquisition means capable of acquiring position information of the vibration compactor;
a rolling number calculation means for dividing the surface of the ground into a plurality of areas and calculating the number of times each of the areas has been rolled by the vibrating rolling machine based on the position information acquired by the position information acquisition means;
a compaction index value calculation means for calculating an index value indicating the compaction state of the ground compacted by the vibrating roller for each of the plurality of regions by performing frequency analysis on the vibration acceleration acquired by the acceleration acquisition means;
a moisture content acquiring means for acquiring the moisture content of the ground compacted by the vibrating roller for at least each of the plurality of regions;
a database that stores the index value calculated by the compaction index value calculation means and the moisture content ratio acquired by the moisture content ratio acquisition means in association with the number of times of compaction for each of the plurality of regions;
and an output processing means capable of outputting the number of times of compaction, the index value, and the moisture content stored in the database for each of the plurality of regions. The quality control system according to claim 1 , further comprising a material change determination means for determining whether or not the soil material has changed for each of the plurality of regions based on the change in the moisture content acquired by the moisture content acquisition means. The quality control system according to claim 1 or 2, wherein the moisture content acquisition means is mounted on a mobile body that can travel autonomously or follow the travel path of the vibrating roller. an acceleration acquiring means for acquiring vibration acceleration of a vibrating roller that compacts the ground by transmitting vibration to the ground;
a position information acquisition means capable of acquiring position information of the vibration compactor;
a rolling number calculation means for dividing the surface of the ground into a plurality of areas and calculating the number of times each of the areas has been rolled by the vibrating rolling machine based on the position information acquired by the position information acquisition means;
a compaction index value calculation means for calculating an index value indicating the compaction state of the ground compacted by the vibrating roller for each of the plurality of regions by performing frequency analysis on the vibration acceleration acquired by the acceleration acquisition means;
a database that stores the index value calculated by the compaction index value calculation means in association with the number of times of compaction for each of the plurality of regions;
an output processing means capable of outputting the number of times of compaction and the index value stored in the database for each of the plurality of regions,
The compaction index value calculation means
This quality control system is characterized in that, when the transmission depth of the vibration force of the vibrating compactor is deeper than the thickness of the construction layer that can be compacted in one compaction operation, a correction process is performed to remove the influence of the lower layer when calculating the index value of the current construction layer. The method further includes a subsidence amount acquisition means capable of acquiring a subsidence amount, which is a vertical displacement amount of the ground compacted by the vibrating compactor, for at least each of the plurality of regions,
The database stores the subsidence amount acquired by the subsidence amount acquisition means in association with the number of times of compaction for each of the plurality of regions,
The quality control system according to claim 1 , wherein the output processing means is capable of outputting the subsidence amount stored in the database for each of the plurality of regions. The quality control system of claim 5, further comprising a compaction determination means for determining whether the ground has been compacted based on the convergence trend of the index value calculated by the compaction index value calculation means and/or the convergence trend of the subsidence amount acquired by the subsidence amount acquisition means. The compaction index value calculation means
7. The quality control system according to claim 1, wherein a first predetermined number of vibration acceleration data is defined as a processing unit required for one frequency analysis, and each time a second predetermined number of vibration acceleration data that is smaller than the processing unit is acquired, frequency analysis is performed using the vibration acceleration data of the processing unit that includes the second predetermined number of vibration acceleration data most recently acquired, thereby executing a shift process to make the calculation period of the index value shorter than the sampling period of the vibration acceleration data. The quality control system according to any one of claims 1 to 7 , wherein the compaction index value calculation means calculates, as the index value, an acceleration response value obtained by the frequency analysis and a ground deformation coefficient obtained from the acceleration response value. A rolling compaction work is carried out to compact the ground using a vibrating rolling machine that transmits vibrations to the ground,
Acquire position information of the vibrating roller in parallel with the rolling compaction,
The ground is divided into a plurality of areas, and the number of times each of the areas is compacted by the vibrating compactor is calculated based on the position information;
acquiring the vibration acceleration of the vibrating roller and performing frequency analysis on the acquired vibration acceleration, thereby calculating an index value indicating the compaction state of the ground compacted by the vibrating roller for each of the plurality of regions;
Obtaining the water content of the ground compacted by the vibrating roller for at least each of the plurality of regions;
constructing a database that stores the index value calculated for each of the plurality of regions and the moisture content ratio obtained for each of the plurality of regions in association with the number of times of compaction;
a quality control method for outputting the number of times of compaction, the index value, and the moisture content stored in the database for each of the plurality of regions,