Quality control system, quality control method, and quality control program

Abstract

To improve efficiency in evaluating a construction surface in earthwork.SOLUTION: A quality management system includes one or more computers configured to acquire a first height of a construction surface before spreading, a second height of the construction surface after spreading, and a third height of the construction surface after compaction by a compactor, calculate a compression ratio based on a ratio of the second height to the third height with respect to a difference between the second height and the first height, and calculate an estimated value of a compaction density according to the calculated compression ratio by using a relational expression representing a relationship between the compression ratio and the compaction density created in advance.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a quality control system, a quality control method, and a quality control program for controlling the quality of earthworks. [Background technology]

[0002] Conventionally, a system for evaluating the compaction state of ground has been proposed (for example, Patent Document 1). This system includes an acceleration sensor that acquires the vibration acceleration of a vibrating compactor that compacts the ground, a GNSS that acquires position information of the vibrating compactor, a compaction count calculation unit that divides the ground into multiple regions and calculates the number of times each region is compacted by the vibrating compactor, a compaction index value calculation unit that calculates an index value indicating the compaction state of the ground for each region by performing frequency analysis of the vibration acceleration, a database that stores the calculated index value in association with the number of compactions for each region, and an output processing unit that can output the number of compactions and index values ​​stored in the database for each of the multiple regions. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-016137 Summary of the Invention [Problem to be solved by the invention]

[0004] Depending on the type of soil used in earthworks, it may be difficult to estimate density based on ground stiffness based on vibration acceleration. In addition, evaluating ground density over a wide area of ​​construction sites generally requires time and effort.

[0005] The present invention aims to improve the efficiency of density evaluation of construction surfaces in earthworks. [Means for solving the problem]

[0006] In order to solve the above problems, the following measures are adopted. (Aspect 1) Acquiring a first height of the construction surface before spreading, a second height of the construction surface after spreading, and a third height of the construction surface after compaction by the compactor; calculating a compression ratio based on a ratio of a difference between the second height and the third height to a difference between the second height and the first height; Calculating an estimated value of compaction density according to the calculated compression rate using a relational expression that represents the relationship between the compression rate and the compaction density, which has been created in advance; a quality control system including one or more computers running (Aspect 2) The estimated values ​​of the first height, the second height, the third height, the compression ratio, and the compaction density are calculated for each area obtained by dividing the construction surface. 2. The quality control system of embodiment 1. (Aspect 3) The one or more computers further output information indicating sections in which the estimated values ​​do not meet a predetermined standard. 3. The quality control system of embodiment 2. (Aspect 4) Information indicating the sections where the estimated value does not meet the predetermined standard may be provided by measuring the density of the sections or contains information to instruct other devices to perform additional work. 4. The quality control system of embodiment 3. (Aspect 5) the first height, the second height, and the third height are measured by a non-contact distance measuring sensor; If there is a missing section in which data of the first height, the second height, or the third height is missing, the one or more computers complement the data of the missing section based on data of surrounding sections. A quality control system according to any one of aspects 2 to 4. (Aspect 6) Acquiring a first height of the construction surface before spreading, a second height of the construction surface after spreading, and a third height of the construction surface after compaction by the compactor; calculating a compression ratio based on a ratio of a difference between the second height and the third height to a difference between the second height and the first height; Calculating an estimated value of compaction density according to the calculated compression rate using a relational expression that represents the relationship between the compression rate and the compaction density, which has been created in advance; One or more computer-implemented quality control methods. (Aspect 7) Acquiring a first height of the construction surface before spreading, a second height of the construction surface after spreading, and a third height of the construction surface after compaction by the compactor; calculating a compression ratio based on a ratio of a difference between the second height and the third height to a difference between the second height and the first height; Calculating an estimated value of compaction density according to the calculated compression rate using a relational expression that represents the relationship between the compression rate and the compaction density, which has been created in advance; A quality control program for running on one or more computers.

[0007] The contents of the means for solving the problem can be combined as much as possible without departing from the problem and technical idea of ​​the present invention. Furthermore, the contents of the means for solving the problem can be provided as a device such as a computer or a system including multiple devices, a method executed by a computer, or a program executed by a computer. The program can also be executed over a network. A recording medium storing the program may also be provided. [Effects of the Invention]

[0008] According to the present invention, it is possible to improve the efficiency of density evaluation of construction surfaces in earthworks. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a quality control system. [Figure 2] FIG. 2 is a block diagram showing an example of a quality control system. [Figure 3] FIG. 3 is a flow diagram showing an example of an earthwork process. [Figure 4] FIG. 4 is a flowchart illustrating an example of the density estimation process. [Figure 5] FIG. 5 is a schematic diagram showing an example of an embankment. [Figure 6] FIG. 6 is a diagram for explaining the relational expression between compressibility and dry density. [Figure 7] FIG. 7 is a diagram for explaining the estimated value of dry density and the actually measured value of dry density. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment will be described with reference to the drawings. The configurations shown in the embodiments are merely examples, and the present invention is not limited to the specific configurations of the embodiments. That is, when implementing the present invention, Various configurations can be appropriately adopted within the scope of the object and technical idea of ​​the present invention.

[0011] <Configuration example> FIG. 1 is a diagram showing an example of the configuration of a quality control system. FIG. 2 is a block diagram showing an example of a quality control system. The quality control system 100 accumulates information obtained from heavy machinery and surveying equipment in earthworks such as road embankments, fill dams, concrete dams, levees, and residential land development, and performs management and quality evaluation. The quality control system 100 shown in FIGS. 1 and 2 includes a server 1, a terminal 2 (FIG. 1: 2A, 2B), a bulldozer 3, a vibrating roller 4, a laser scanner 5, and a measuring device 6. These components may be communicatively connected via a network 7.

[0012] The server 1 is a computer connected to a network 7. As shown in FIG. 2, the server 1 includes a processor 11, a storage device 12, and a communication interface (IF) 13. The processor 11 is an arithmetic processing device such as a CPU (Central Processing Unit). The storage device 12 is, for example, a main storage device such as a RAM (Random Access Memory) or a ROM (Read Only Memory), or an auxiliary storage device such as an HDD (Hard-Disk Drive), an SSD (Solid State Drive), an eMMC (Embedded Multi-Media Card), or a flash memory. The auxiliary storage device temporarily stores programs read by the processor 11 and information sent and received between other computers, and secures a working area for the processor 11. The auxiliary storage device stores programs executed by the processor 11 and information sent and received between other computers. The communication IF 13 is, for example, a network card or a communication module, and communicates with other computers based on a predetermined communication protocol.

[0013] Server 1 accumulates data acquired from other devices and evaluates quality based on the data. For example, server 1 may be a cloud system that uses ICT (Information and Communication Technology) to control the quality of various earthwork processes and maintain the constructed structures. Server 1 may also create information to control bulldozer 3, vibratory roller 4, laser scanner 5, or measuring device 6.

[0014] The terminal 2 is a device used by a user, such as a PC (Personal Computer), a tablet, etc. The terminal 2 shown in Fig. 2 includes a processor 21, a storage device 22, a communication interface (IF) 23, and a user interface (UI) 24. The processor 21, the storage device 22, and the communication IF 23 are the same as the processor 11 and the storage device 12 of the server 1, respectively. The UI 24 is an input / output device such as a touch panel, a keyboard, or a pointing device. The terminal 2 accepts user operations and outputs information to the user via the UI 24.

[0015] Based on user operations, the terminal 2 acquires and displays information held by the server 1, and instructs the server 1 to process data. The terminal 2 may acquire data from the bulldozer 3, the vibrating roller 4, the laser scanner 5, or the measuring device 6 via the network 7 or via a storage medium, process the data, and send it to the server 1. Based on user operations, the terminal 2 may also create information for controlling the bulldozer 3, the vibrating roller 4, the laser scanner 5, or the measuring device 6.

[0016] The bulldozer 3 is a heavy machine for spreading earth and sand. The bulldozer 3 according to this embodiment is equipped with a positioning device 31 and an imaging device 32, and is used to take an image of the surface of the embankment after spreading. The positioning device 31 is a module that receives signals from, for example, a Global Navigation Satellite System (GNSS) to calculate coordinates indicating the location of the positioning device 31 and outputs the coordinates as location information. The imaging device 32 is a digital camera that converts light into an electrical signal using an imaging element such as a CCD or CMOS, creates image data, and outputs it. The lens of the imaging device 32 is not particularly limited, but a wide-angle lens is preferable. The lens of the imaging device 32 may also be equipped with a halation-cutting filter such as a polarizing filter. The bulldozer 3 may also be equipped with a computer that is communicatively connected to other devices via the network 7 and transmits image data to the server 1. The computer may have a configuration similar to that of the server 1 and be connected to the positioning device 31 and the imaging device 32.

[0017] The vibrating roller 4 is a heavy machine (rolling machine) for compacting, for example, embankment soil. The object to be compacted is, for example, a concrete pile laid in an RCD (Roller Compacted Dam-Concrete) construction method. The vibratory roller 4 according to this embodiment is equipped with a positioning device 41 and an acceleration sensor 42, which measures vibration acceleration during compaction and records it in association with position information. The positioning device 41 is the same as the positioning device 31 of the bulldozer 3. The acceleration sensor 42 is an inertial sensor that detects and outputs the moving speed per unit time. The acceleration sensor 42 is mounted on a frame that supports the compaction wheels of the vibratory roller 4, and detects vibration acceleration in at least the vertical direction. The compaction wheels are vibrated in the vertical direction by an excitation device to compact the ground. The vibratory roller 4 may also be equipped with a computer that is connected to other devices via the network 7 so as to be able to communicate with them, and which transmits acceleration data to the server 1.

[0018] The laser scanner 5 is a surveying instrument equipped with a laser sensor that emits laser light and receives the reflected light, and is used to measure the three-dimensional coordinates of the earth's surface. The laser scanner 5 outputs point cloud data that represents the coordinates of the earth's surface, and stores the data in an internal memory or a portable storage medium. The laser scanner 5 may also be capable of transmitting the measured point cloud data to the server 1 via the network 7. The laser scanner 5 is, for example, a terrestrial laser scanner (TLS), but is not limited to this. It may also be a UAV-mounted laser scanner (ULS) or the like.

[0019] The measuring device 6 is a self-propelled device equipped with a predetermined sensor and drive mechanism, and outputs an index value for evaluating the condition of the ground. The index value may be, for example, the density (wet density) of the ground (subsurface), or the water content or water content ratio. The measuring device 6 is, for example, an apparatus that uses a scattering type RI (Radio Isotope) and is equipped with a positioning device 61, a radiation source 62, and a detector 63. The positioning device 61 is the same as the positioning device 31 of the bulldozer 3. The radiation source 62 is a radiation source (radioisotope) that emits radiation. The radiation source 62 irradiates the ground with, for example, neutron rays or gamma rays. The detector 63 is a detector that detects radiation that is irradiated from the radiation source 15 and scattered by the ground (subsurface). The detector 63 measures the wet density (water content ratio) by the RI (Radio Isotope) method. ), moisture content, etc., may be calculated and output. Furthermore, the measuring device 6 or the server 1 may calculate the dry density γd based on the following formula 1, for example, using the moisture content w and the wet density γt. γd=γt / (1+w / 100) (1)

[0020] The measuring device 6 may also include a computer communicably connected to other devices via the network 7, and may transmit data to the server 1. The computer may have, for example, the same configuration as the server 1, and be connected to the positioning device 61 and the detector 63. The computer may also control a driving motor that drives the wheels and a steering motor that changes the steering angle of the wheels, and may control autonomous driving based on, for example, a predetermined driving route and the position information of the device itself.

[0021] The network 7 includes, for example, an IP (Internet Protocol) network. Devices connected to the network 7 can communicate based on a predetermined communication protocol. Part of the network 7 may be a telephone network (fixed telephone network or mobile communication network), an ad hoc network, an intranet, a VPN (Virtual Private Network), a LA (Land-based Virtual Private Network), or a similar network. N (Local Area Network), Wireless LAN, WAN (Wide Area Network) ), or the Internet.

[0022] <Processing> FIG. 3 is a flow diagram showing an example of an earthwork process. This embodiment will be described mainly using the construction of an embankment as an example, but the construction surface may also be a paved road, a concrete dam, or the like. The user uses a laser scanner 5 to perform a laser scan of the ground (FIG. 3: S1). In this process, the laser scanner 5 outputs point cloud data representing the coordinates of the ground surface. Targets are installed in advance at control points whose public coordinates are known from surveying so that the coordinates of the control points in the point cloud data can be determined. Known targets, such as spheres (spherical markers) and prisms, can be used as targets. In this step, point cloud data corresponding to the height (altitude) of the ground before spreading (FIG. 1: L1) is created. The point cloud data is stored in the server 1 or the terminal 2.

[0023] After S1, the user uses the bulldozer 3 to carry out spreading (S2 in FIG. 3). In this process, while the spreading work is being carried out, the imaging device 32 captures an image of the surface of the embankment after spreading, and records the image in association with the location information output by the positioning device 31. The image data including the location information is stored in the server 1.

[0024] After S2, the user uses the laser scanner 5 to perform a laser scan of the ground (S3 in Figure 3). This process is similar to S1, but it also creates point cloud data corresponding to the height (elevation) of the embankment (L2 in Figure 1) after spreading.

[0025] After S3, the user performs compaction using the vibrating roller 4 (S4 in Figure 3). In this process, while compaction work is being performed, the acceleration sensor 42 measures the vibration acceleration and records it in association with the location information output by the positioning device 41. The acceleration data associated with the location information is stored in the server 1. Compaction is also performed repeatedly on the ground. The acceleration data is associated with information indicating, for example, the date and time of measurement, making it possible to identify which compaction work the acceleration data is from.

[0026] After S4, the user uses a laser scanner 5 to perform a laser scan of the ground (S5 in Figure 3). This process is similar to S1, but it also creates point cloud data corresponding to the height (elevation) of the compacted fill (L3 in Figure 1).

[0027] The compaction work is repeated, for example, a predetermined number of times. After S5, it is determined whether to repeat the compaction work (Fig. 3: S6), and if the predetermined number of times is not reached (S6: YES), the process returns to S4 and the compaction work is repeated. Note that the laser scan in S5 may be performed after each of multiple compaction work operations, such as the second, fourth, sixth, etc.

[0028] On the other hand, if compaction has been performed a predetermined number of times (S6: NO), density estimation is performed (Fig. 3: S7). Fig. 4 is a flow diagram showing an example of density estimation processing. Note that the point cloud data is assumed to be stored in the terminal 2 via a portable storage medium or the network 7.

[0029] The processor 21 of the terminal 2 reads out the point cloud data from the storage device 22 (FIG. 4: S11). The point cloud data is a plurality of coordinate data in the local coordinate system output by the laser scanner 5.

[0030] After S11, the processor 21 transforms the point cloud data into public coordinates (FIG. 4: S12). Since the latitude and longitude of the control points are known by surveying, in this step, the entire point cloud data can be transformed (projectively transformed) based on the coordinates of the control points included in the point cloud data.

[0031] After S12, the processor 21 calculates the average elevation for each mesh of a predetermined size that divides the ground (S13 in FIG. 4). The average elevation is, for example, the arithmetic mean of the elevations of the point cloud data converted into public coordinates. FIG. 5 is a schematic diagram showing an example of an embankment. The embankment B1 is divided into multiple meshes A1, A2, ..., and the elevations of the point cloud data included in each mesh are averaged. Note that the size of the mesh is not particularly limited, and may be, for example, a square with a side length of 50 cm. When the laser scanner 5 is a TLS, the density of the created point cloud data is generally higher the closer to the laser scanner 5 and lower the farther away from the laser scanner 5. Note that even if the point cloud data is too close, the density may be low depending on the incident angle of the laser. In S13, one mesh contains, for example, several tens to tens of thousands of points.

[0032] After S13, the processor 21 performs mesh interpolation (S14 in FIG. 4). As described above, for example, the density of points whose coordinates can be measured decreases in areas farther from the laser scanner 5. In this step, if there is a mesh that does not contain any points and therefore lacks an average elevation, an interpolated value is calculated based on the average elevation of the surrounding meshes. The interpolated value may be the arithmetic mean of the average elevations of the surrounding meshes, or the arithmetic mean of all point cloud data included in the surrounding meshes. Furthermore, the surrounding meshes to be averaged may be meshes that pass before and after the mesh with the defect in the travel path of, for example, the bulldozer 3 or the vibratory roller 4. The arrow R1 in FIG. 5 is an example of a travel path. Note that in the example in FIG. 5, the width of the travel path and the width of the mesh are shown to be the same, but, for example, the width of the travel path may be larger than the width of the mesh. By averaging the meshes before and after the travel path of the heavy equipment, the height of the mesh with the defect can be accurately estimated. Note that the surrounding meshes to be averaged may be meshes adjacent to the four sides of the mesh with the defect, or meshes further adjacent to these.

[0033] The calculation of the height for each mesh as described above is performed for the first height of the construction surface before spreading, the second height of the construction surface after spreading, and the third height of the construction surface after compaction. Furthermore, it is preferable to calculate the third height of the construction surface after compaction in more detail in association with the number of compactions.

[0034] After S14, the processor 21 calculates the compression rate due to rolling compaction for each mesh (S15 in FIG. 4). In this step, the compression rate is calculated based on the ratio of the difference between the second height and the third height (subsidence amount D2 in FIG. 1) to the difference between the second height and the first height (spreading thickness D1 in FIG. 1). For example, the compression rate can be calculated using the following equation 2. The compression rate is calculated for each mesh. Compression rate (%) = (subsidence amount D2 / spreading thickness D1) × 100 (2)

[0035] In this embodiment, after S15, the processor 21 transmits the calculated compression rate data to the server 1, and the subsequent processing is performed by the processor 11 of the server 1. The processor 11 estimates the density of the construction surface based on the compression rate calculated in S15 (FIG. 4: S16). For example, a relational expression is created in advance by approximating the relationship between the compression rate and dry density measured using a test embankment. The dry density is then estimated based on the compression rate using the relational expression. The estimated density value is also calculated for each mesh. The degree of the estimated density value may be visualized using a heat map for the construction surface divided into meshes.

[0036] FIG. 6 is a diagram for explaining the relational expression between the compressibility and the dry density, which is prepared in advance. In the graph of FIG. 6, the horizontal axis represents the compressibility obtained from the measurement results of the laser scanner, and the vertical axis represents the dry density. The dry density is the dry density measured by a transmission type RI, which inserts a radiation source into the ground to perform the measurement. The dry density used to prepare the relational expression may be a value actually measured by the well-known RI (Radio Isotope) method or the sand displacement method. Based on these data, As a relational expression for estimating the dry density from the compressibility, an approximate expression such as that shown by the dashed line in Figure 6 can be created.

[0037] FIG. 7 is a diagram for explaining the estimated dry density and the measured dry density. The horizontal axis of FIG. 7 represents the timing of the estimation of the dry density in terms of the number of times of compaction. The vertical axis of FIG. 7 represents the dry density. The data points represented by triangles are the results of transmission RI (Radio Isotope) measurements. The dry density measured by the laser scanner is shown in Figure 6. The data points represented by circles are the estimated dry density values ​​calculated using the relational equation in S15. As shown in Figures 6 and 7, a high correlation was observed between the compressibility and dry density, and the dry density estimated based on the laser scanner measurements was in close agreement with the transmission RI value.

[0038] This completes the density estimation process shown in FIG. 4, and the process returns to FIG. 3. The processor 11 compares the estimated density value with a predetermined standard (threshold value) to determine whether it is sufficient (FIG. 3: S8). In this step, it is determined whether the quality of the construction surface is sufficient based on the predetermined standard. If it is determined to be insufficient (S8: NO), the processor 11 outputs information indicating the areas where the density is determined to be insufficient (FIG. 3: S9). In this step, the processor 21 may, for example, send data to the measuring device 6 to cause it to measure the density using scattering-type RI. The processor 21 may also send data to the vibrating roller 4 to cause it to perform additional compaction work.

[0039] In S9, it may be determined whether the quality is sufficient based on the above-mentioned compression ratio instead of the density. Also, it may be determined whether the quality is sufficient based on the ground stiffness obtained from the acceleration data of the vibrating roller 4.

[0040] Furthermore, in S9, the processor 11 may read the image of the surface of the embankment after spreading, taken in S2 of Fig. 3, for the area where the quality was determined to be insufficient and its surroundings, and transmit it to the terminal 2. In this way, the user of the terminal 2 can visually confirm whether the reason for the determination that the quality was insufficient is due to the embankment material itself or a difference in the moisture content of the embankment material compared to the surrounding area.

[0041] Furthermore, the data created in the embodiment may be stored for a long period of time in association with location information. If any problem occurs during the maintenance stage of a structure such as a road constructed on a construction surface, it will be possible to verify the type of ground, asphalt, or concrete pavement used at the time of construction.

[0042] <Effects> According to this embodiment, the density of the construction surface after compaction can be accurately estimated based on the height of the construction surface measured using the laser scanner 5. For example, when construction is carried out in a short period of time, such as in the RCD (Roller Compacted Dam-concrete) construction method, the density of the construction surface can be accurately estimated using the measuring device 6. It is difficult to secure the time to actually measure the density of the entire surface. Also, since the stiffness of the ground changes depending on the age (number of days elapsed), it is difficult to estimate density based on the stiffness of the ground. With the laser scanner 5, even with this type of construction method, it is possible to measure a wide range of construction surfaces in real time and estimate construction quality. In addition, weak areas are estimated based on a comparison of the density, compression rate, stiffness, etc. of the construction surface with predetermined thresholds, and the estimated weak areas are verified using a measuring device 6. In addition, depending on the results of the verification of weak areas, for example, additional compaction using the vibrating roller 4 or compaction after replacing the embankment material can be carried out, thereby improving the quality of construction.

[0043] In addition to laser scanners, LiDAR (Light Detection and Ranging) Various non-contact distance measurement sensors such as a depth camera can be used. The distance measurement sensor generates depth information using, for example, a time-of-flight (TOF) method, a phase difference measurement method, a triangulation method, or the like, and can identify the surface shape of the measurement target based on the depth information.

[0044] <Other> The above-described embodiment is merely an example, and the present invention is not limited to the above-described configuration. The steps shown in Figures 3 and 4 can be modified as appropriate depending on the type of earthwork. In other words, some of the steps described in the embodiment may be omitted, or other steps may be added.

[0045] The present invention also covers a computer program for executing the above-described process and a computer-readable recording medium having the program recorded thereon. The recording medium having the program recorded thereon enables the above-described process by causing a computer to execute the program.

[0046] A computer-readable recording medium is a recording medium that stores information such as data and programs electrically, magnetically, optically, mechanically, or chemically and can be read by a computer. Among such recording media, those that can be removed from a computer include flexible disks, magneto-optical disks, optical disks, magnetic tapes, memory cards, etc. Furthermore, recording media that are fixed to a computer include HDDs, SSDs, ROMs, etc. [Explanation of symbols]

[0047] 100:Quality Control System 1: Server, 11: Processor, 12: Storage device, 13: Communication interface 2: Terminal, 21: Processor, 22: Storage device, 23: Communication interface, 24: User interface 3: Bulldozer, 31: Positioning device, 32: Imaging device 4: Vibration roller, 41: Positioning device, 42: Acceleration sensor 5: Laser scanner 6: Measuring device, 61: Positioning device, 62: Radiation source, 63: Detector 7: Network

Claims

1. Acquiring a first height of the construction surface before spreading, a second height of the construction surface after spreading, and a third height of the construction surface after compaction by the compactor; calculating a compression ratio based on a ratio of a difference between the second height and the third height to a difference between the second height and the first height; Calculating an estimated value of compaction density according to the calculated compression rate using a relational expression that represents the relationship between the compression rate and the compaction density, which has been created in advance; A quality control system comprising one or more computers running

2. The estimated values ​​of the first height, the second height, the third height, the compressibility, and the compaction density are calculated for each area obtained by dividing the construction surface. The quality control system of claim 1 .

3. The one or more computers further output information indicating sections in which the estimated values ​​do not meet a predetermined standard. The quality control system according to claim 2 .

4. The information indicating the section where the estimated value does not meet the predetermined standard includes information for instructing another device to measure the density of the section or to carry out additional construction work. The quality control system according to claim 3 .

5. the first height, the second height, and the third height are measured by a non-contact distance measuring sensor; If there is a missing section in which data of the first height, the second height, or the third height is missing, the one or more computers complement the data of the missing section based on data of surrounding sections. A quality control system according to any one of claims 2 to 4.

6. Acquiring a first height of the construction surface before spreading, a second height of the construction surface after spreading, and a third height of the construction surface after compaction by the compactor; calculating a compression ratio based on a ratio of a difference between the second height and the third height to a difference between the second height and the first height; Calculating an estimated value of compaction density according to the calculated compression rate using a relational expression that represents the relationship between the compression rate and the compaction density, which has been created in advance; A quality control method implemented by one or more computers.

7. Acquiring a first height of the construction surface before spreading, a second height of the construction surface after spreading, and a third height of the construction surface after compaction by the compactor; calculating a compression ratio based on a ratio of a difference between the second height and the third height to a difference between the second height and the first height; Calculating an estimated value of compaction density according to the calculated compression rate using a relational expression that represents the relationship between the compression rate and the compaction density, which has been created in advance; A quality control program for executing the above on one or more computers.

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