Embankment evaluation system and method for evaluating embankment

Abstract

To provide an embankment evaluation system and a method for evaluating embankment capable of improving the accuracy of embankment quality evaluation.SOLUTION: An embankment evaluation system according to one embodiment includes: a resistivity measurement unit 10 having a pair of potential electrodes 41 and a pair of current electrodes 42 for measuring the resistivity of an embankment B while facing the embankment B; a traction unit for moving the resistivity measurement unit 10 along the embankment B; a camera 50 for capturing an image of a portion of the embankment B whose resistivity is measured by the resistivity measurement unit 10; and a quality evaluation unit for evaluating the quality of the embankment B using the resistivity measured by the resistivity measurement unit 10 and the image of the embankment B captured by the camera 50.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an embankment evaluation system and an embankment evaluation method for evaluating embankments. [Background technology]

[0002] Patent Document 1 describes a soil measurement method and a soil measurement device. The soil measurement method includes an electrical resistivity measurement step, a soil portion dry density deriving step, and an overall dry density deriving step. In the electrical resistivity measurement step, the electrical resistivity of the ground material is measured. In the soil portion dry density deriving step, the dry density of the soil portion of the ground material is measured based on the electrical resistivity of the ground material measured in the electrical resistivity measurement step and a predetermined relationship between the electrical resistivity and dry density of the soil portion from which gravel and stone have been removed. In the overall dry density deriving step, the dry density of the ground material is derived based on the dry density of the soil portion of the ground material derived in the soil portion dry density deriving step, the density of the gravel and stone content of the ground material, and the gravel and stone content, which is the ratio of the mass of the gravel and stone content to the mass of the ground material.

[0003] The soil measurement device comprises a central frame, an electrode unit towed by the central frame, and drive wheels attached to the central frame for moving the soil measurement device over the ground material. The electrode unit contacts the surface of the ground material. The electrode unit has auxiliary wheels, a towing body towed by the central frame, and four wheel-shaped electrodes connected to the rear of the towing body. The outer circumferential surfaces of the wheel-shaped electrodes contact the surface of the ground material. The electrical resistance of the ground material is measured by the wheel-shaped electrodes that move over the ground material and come into contact with it. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-90386 Summary of the Invention [Problem to be solved by the invention]

[0005] When measuring the resistivity of an embankment and using it to evaluate the embankment, areas with low resistivity are determined to be areas with high density, and areas with high resistivity are determined to be areas with low density. Resistivity is measured by bringing multiple electrodes into contact with the embankment, as with the wheel-shaped electrode mentioned above. However, there are areas in the embankment that contain a lot of large gravel, and in these areas, a lot of air can get trapped between the embankment and the electrodes.

[0006] If a large amount of air gets between the embankment and the electrode, the resistivity may be measured high even though the density is not actually low, resulting in an erroneous measurement that the density is low. In this way, if the density is measured low even though it is not actually low, the quality of the embankment may be erroneously evaluated as poor. Therefore, there is room for improvement in the accuracy of embankment quality evaluation.

[0007] The present disclosure aims to provide an embankment evaluation system and an embankment evaluation method that can improve the accuracy of embankment quality evaluation. [Means for solving the problem]

[0008] (1) The embankment evaluation system according to the present disclosure comprises a resistivity measurement unit having a pair of potential electrodes and a pair of current electrodes that measure the resistivity of the embankment while facing the embankment, a traction unit that moves the resistivity measurement unit in the embankment, a camera that photographs the portion of the embankment whose resistivity is measured by the resistivity measurement unit, and a quality evaluation unit that evaluates the quality of the embankment using the resistivity measured by the resistivity measurement unit and an image of the embankment photographed by the camera.

[0009] In this embankment evaluation system, a resistivity measurement unit measures the resistivity of the embankment with a pair of potential electrodes and a pair of current electrodes facing the embankment. The resistivity measurement unit measures the resistivity of the embankment while being towed by a towing unit. This embankment evaluation system is equipped with a camera, which photographs the portion of the embankment where the resistivity is to be measured. A quality evaluation unit, which evaluates the quality of the embankment, uses the resistivity measured by the resistivity measurement unit and images of the embankment photographed by the camera. Thus, the quality of the embankment is evaluated not only from the resistivity but also from the image of the embankment where the resistivity is measured. Since the actual condition of the embankment can be grasped by acquiring images of the embankment, adjusting the measured resistivity value using the images can avoid measuring the resistivity high when the density is not actually low. Therefore, measuring a low density when the density is not actually low can be avoided, and erroneous evaluation of the quality of the embankment as poor can be prevented. As a result, the accuracy of the embankment quality evaluation can be improved.

[0010] (2) In (1) above, the resistivity measurement unit may be moved along the movement direction by a towing unit. The camera may be moved along the movement direction together with the resistivity measurement unit on the opposite side of the movement direction from the resistivity measurement unit. In this case, when the resistivity measurement unit moves forward, the camera is positioned behind the resistivity measurement unit. The camera then moves along the movement direction together with the resistivity measurement unit behind the resistivity measurement unit. Therefore, resistivity measurement and photographing of the embankment can be performed while towing, allowing for efficient evaluation of the embankment.

[0011] (3) In the above (1) or (2), the embankment evaluation system may include a resistivity determination unit that determines whether the resistivity measured by the resistivity measurement unit is equal to or greater than the resistivity threshold. The camera may photograph the portion of the embankment whose resistivity is determined by the resistivity determination unit to be equal to or greater than the resistivity threshold. In this case, the camera can photograph only the portion of the embankment whose resistivity is equal to or greater than the resistivity threshold, thereby minimizing the number of photographs taken by the camera.

[0012] (4) In any of (1) to (3) above, the embankment evaluation system may include a resistivity determination unit that determines whether the resistivity measured by the resistivity measurement unit is equal to or greater than a resistivity threshold, and a gravel ratio calculation unit that calculates the gravel ratio of the embankment from an image of the embankment captured by a camera. The quality evaluation unit may evaluate the quality of the embankment as good when the resistivity determination unit determines that the resistivity is equal to or greater than the resistivity threshold and the gravel ratio calculated by the gravel ratio calculation unit is equal to or greater than the gravel ratio threshold. In this case, it is possible to prevent an erroneous evaluation that the quality of an embankment whose gravel ratio is equal to or greater than the gravel ratio threshold is poor. Therefore, the accuracy of the quality evaluation of the embankment can be further improved.

[0013] (5) In any of (1) to (4) above, the embankment evaluation system may include a gravel ratio calculation unit that calculates the gravel ratio of the embankment from an image of the embankment captured by a camera, and a moisture meter that measures the volumetric water content of the embankment while facing the embankment. The quality evaluation unit may calculate the density of the embankment from the resistivity measured by the resistivity measurement unit and the volumetric water content measured by the moisture meter. The embankment evaluation system may further include a display unit that displays the gravel ratio calculated by the gravel ratio calculation unit together with the density. In this case, the gravel ratio is displayed on the display unit along with the density, allowing the results of the quality evaluation to be visually understood from the display unit.

[0014] (6) In any of the above (1) to (5), the embankment evaluation system may include a moisture meter that faces the embankment and measures the volumetric moisture content of the embankment. The moisture meter may be a scattering-type RI moisture meter. In this case, the volumetric moisture content can be measured with higher accuracy, thereby further improving the accuracy of the quality evaluation of the embankment.

[0015] (7) The embankment evaluation method according to the present disclosure comprises the steps of measuring the resistivity of the embankment with a pair of potential electrodes and a pair of current electrodes facing the embankment, photographing the portion of the embankment whose resistivity is measured in the resistivity measuring step, and determining the quality of the embankment using the resistivity measured in the resistivity measuring step and the image of the embankment photographed in the photographing step.

[0016] In this embankment evaluation method, the resistivity of an embankment is measured with a pair of potential electrodes and a pair of current electrodes facing the embankment, and the portion of the embankment where the resistivity is to be measured is photographed. The measured resistivity and the photographed image of the embankment are then used to evaluate the quality of the embankment. Therefore, since the quality of the embankment is evaluated not only from the resistivity but also from the image of the embankment where the resistivity is measured, the actual condition of the embankment can be grasped by acquiring the image of the embankment, as in the embankment evaluation system described above. Therefore, by adjusting the measured resistivity value using the image, it is possible to avoid measuring the resistivity as high when the actual density is not low. As a result, it is possible to avoid measuring the density as low when the actual density is not low, and to prevent the erroneous evaluation of the quality of the embankment as poor, thereby improving the accuracy of the embankment quality evaluation.

[0017] (8) In the above (7), the embankment evaluation method may further include a step of re-measuring the resistivity of the embankment and / or rolling compacting the embankment if the quality of the embankment is determined to be poor in the step of determining the quality of the embankment. In this case, at least one of re-measuring and rolling compaction is performed on the embankment determined to be poor in quality, thereby making it possible to further improve the quality of the embankment. [Effects of the Invention]

[0018] According to the present disclosure, the accuracy of quality assessment of embankments can be improved. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a diagram showing an example of an embankment evaluation system according to an embodiment. [Figure 2] FIG. 2 is a side view schematically showing the resistivity measuring unit according to the embodiment. [Figure 3] FIG. 3 is a block diagram showing the functions of the embankment evaluation system according to the embodiment. [Figure 4] FIG. 4 is a side view showing the resistivity measuring unit according to the embodiment. [Figure 5] FIG. 5 is a diagram schematically showing the resistivity measuring section of FIG. [Figure 6] FIG. 6 is a diagram schematically showing a map displayed on the display unit according to the embodiment. [Figure 7] FIG. 7 is a flowchart showing an example of steps of the embankment evaluation method according to the embodiment. [Figure 8] FIG. 8 is a graph schematically showing the relationship between resistivity and density, and a calibration curve. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the embankment evaluation system and embankment evaluation method according to the present disclosure will be described with reference to the drawings. In the description of the drawings, the same or corresponding elements are designated by the same reference numerals, and duplicate explanations will be omitted as appropriate. The drawings may be partially simplified or exaggerated for ease of understanding, and the dimensional proportions and the like are not limited to those shown in the drawings.

[0021] The embankment evaluation system 1 and embankment evaluation method according to this embodiment are used, for example, at a site A where a dam is to be constructed. At the site A, as an example, earth and sand is transported by a dump truck, the transported earth and sand is spread and leveled by a bulldozer, and the spread and leveled earth and sand is compacted by a vibrating roller. The vibrating roller travels back and forth multiple times at the site A to compact the embankment B, which is a ground material, and to compact the embankment B at the site A.

[0022] For example, the embankment evaluation system 1 evaluates embankment B (soil and sand) at a site A while traveling over an embankment surface S, which is a compacted surface after compaction by a compaction machine such as a vibrating roller. In this embodiment, the embankment surface S corresponds to the surface to be evaluated by the embankment evaluation system 1. The embankment surface S is a construction surface formed by compaction. The embankment evaluation system 1 calculates, for example, at least one of the density of embankment B and the moisture content of embankment B as evaluation items for embankment B. In this embodiment, the density is at least one of the dry density and the wet density.

[0023] For example, the embankment evaluation system 1 evaluates the embankment B by measuring the density and moisture content of the embankment B, and measures the effectiveness of compaction by a compaction machine. The embankment B may be made of, for example, CSG (Cemented Sand and Gravel) or RCD (Roller Compacted Dam Concrete).

[0024] As shown in Figure 1, the embankment evaluation system 1 comprises a resistivity measurement unit 10 that measures the resistivity of embankment B, a moisture meter 20 that measures the volumetric moisture content of embankment B while facing embankment B, and a towing unit 30. For example, the resistivity measurement unit 10 and the moisture meter 20 are portable devices.

[0025] The towing unit 30, moisture meter 20, and resistivity measurement unit 10 are arranged in this order. As the towing unit 30 tows the moisture meter 20 and resistivity measurement unit 10, the moisture meter 20 and resistivity measurement unit 10 move along a moving direction D1. Hereinafter, the moving direction D1 may be referred to as the front, front side, or forward, and the direction opposite to the moving direction D1 may be referred to as the rear, rear side, or rearward. However, these directions are used for convenience of explanation and do not limit the orientation or placement position of objects.

[0026] For example, the weight of the moisture meter 20 is greater than the weight of the resistivity measurement unit 10. The moisture meter 20 is placed closer to the towing unit 30 than the resistivity measurement unit 10. In this case, the resistivity measurement unit 10 can move more freely behind the moisture meter 20, allowing the resistivity measurement by the resistivity measurement unit 10 to be performed more effectively.

[0027] The embankment evaluation system 1 has a linear body 2 extending from a towing unit 30 to a moisture meter 20, a linear body 3 extending from the moisture meter 20 to a resistivity measurement unit 10, and a linear body 4 located inside the resistivity measurement unit 10. The linear bodies 2, 3, and 4 are, for example, string-like bodies (wires, as an example).

[0028] For example, the towing unit 30 moves the resistivity measuring unit 10 on the embankment B. As an example, the towing unit 30 has a plurality of wheels 30b and a connecting unit 30c that connects the upper parts of the plurality of wheels 30b together. The towing unit 30 may be a traveling vehicle that has a seat and can be driven while sitting on the seat. The connecting unit 30c is connected to the moisture meter 20 via the linear body 2. With the plurality of wheels 30b placed on the mound surface S, the plurality of wheels 30b roll on the mound surface S, allowing the towing unit 30, the moisture meter 20, and the resistivity measuring unit 10 to move along the moving direction D1 on the mound surface S.

[0029] FIG. 2 is a side view showing the resistivity measurement unit 10. As shown in FIGS. 1 and 2, the resistivity measurement unit 10 has a plurality of electrodes 40, a holder 11 that holds the electrodes 40, and a plurality of casters 12 that support the holder 11 so that it can move while being spaced apart from the mound surface S. The plurality of electrodes 40 are a pair of potential electrodes 41 and a pair of current electrodes 42. The resistivity measurement unit 10 has a pair of potential electrodes 41 and a pair of current electrodes 42 that measure the resistivity of the embankment B while facing the embankment B. The resistivity measurement unit 10 has, for example, two holders 11 and a linear body 4 that extends between the two holders 11 along the movement direction D1.

[0030] The linear body 4 is, for example, detachable from the holder 11. In the case where this linear body 4 is provided, when one of the two holders 11 (for example, the holder 11 holding the current electrode 42) is pulled in the movement direction D1, both of the two holders 11 can be moved along the movement direction D1. Furthermore, by preparing a plurality of types of linear bodies 4 with different lengths and attaching a linear body 4 selected from the plurality of types of linear bodies 4, the distance between the potential electrode 41 and the current electrode 42 can be changed. Therefore, the depth at which the resistivity is measured can be changed by changing the distance between the potential electrode 41 and the current electrode 42.

[0031] For example, the holder 11 includes a plurality of electrode holders 13 that hold a pair of potential electrodes 41 and a pair of current electrodes 42, each facing toward the embankment B. The electrode holders 13 hold the electrodes 40 so that they can move along a direction D2 that intersects with the movement direction D1. The direction D2 is, for example, the vertical direction.

[0032] The electrode holding unit 13 has multiple spring mechanisms 16 that urge the electrode 40 toward (downward from) the embankment B. If the holding body 11 travels and there is an unevenness on the embankment surface S, the electrode holding unit 13 and the electrode 40 come into contact with the unevenness, and the electrode 40 moves in direction D2. At this time, the spring mechanisms 16 urge the electrode 40 toward the embankment B, so even if there is an unevenness on the embankment surface S, the electrode 40 can follow the unevenness.

[0033] The moisture meter 20 has, for example, a moisture measuring unit 21, a running body 22, and a holding unit 23 that holds the moisture measuring unit 21 while attached to the underside of the running body 22. The running body 22 has a plurality of wheels 22b and a base 22c provided on the upper part of the plurality of wheels 22b. The holding unit 23 is attached to the underside of the base 22c while holding the moisture measuring unit 21 inside. The holding unit 23 is made of, for example, metal. The holding unit 23 has a recess that houses the moisture measuring unit 21, and the underside of the recess comes into contact with the mound surface S. The moisture measuring unit 21 measures the volumetric moisture content of the embankment B while contacting the mound surface S via the underside, for example.

[0034] For example, the moisture meter 20 is a scattering-type RI moisture meter. In this case, the moisture meter 20 has a radiation source which is a neutron radiation source, a detection tube which is a thermal neutron radiation detection unit, and a housing which houses the radiation source and the detection tube. The radiation source emits fast neutrons to embankment B. The fast neutrons emitted to embankment B are scattered. Some of the scattered fast neutrons collide with hydrogen atoms in embankment B. The fast neutrons that collide with the hydrogen atoms lose their speed and become thermal neutrons. The moisture meter 20 measures the volumetric moisture content of embankment B by detecting the thermal neutrons generated in embankment B with the detection tube. The moisture meter 20 moves over the embankment surface S simultaneously with the movement of the resistivity measurement unit 10 to measure the volumetric moisture content.

[0035] Figure 3 is a block diagram showing the functions of the embankment evaluation system 1. As shown in Figures 1 to 3, for example, the embankment evaluation system 1 has a camera 50 that photographs the embankment B, a data collection unit 60 that collects measurement data measured by each unit of the embankment evaluation system 1, and a display unit 70 that displays the measurement data collected by the data collection unit 60. Note that the camera 50 is not shown in Figure 1 to avoid complexity.

[0036] As an example, the data collection unit 60 is an information terminal such as a personal computer. The data collection unit 60 is provided in the towing unit 30. However, the location of the data collection unit 60 is not particularly limited. The data collection unit 60 may be mounted on the bed of the towing unit 30, which serves as a running body. The data collection unit 60 may include a computer mounted on the running body and a tablet terminal capable of communicating with the computer.

[0037] The display unit 70 is capable of communicating with the data collection unit 60. When the data collection unit 60 is a personal computer, the display unit 70 may be a display of the personal computer. The display unit 70 may also be a display of a mobile terminal (tablet terminal) capable of communicating with the data collection unit 60.

[0038] As an example, the display unit 70 is a display placed in front of the seat of the traveling vehicle. In this case, the driver of the towing unit 30 can visually check the data measured by the data collection unit 60 while traveling the towing unit 30. However, the form of the display unit 70 is not limited to the above example and can be changed as appropriate.

[0039] The camera 50 photographs a portion B1 of the embankment B whose resistivity is to be measured by the resistivity measurement unit 10. The portion B1 may be a portion of the embankment B whose resistivity has been measured by the resistivity measurement unit 10, or it may be a portion whose resistivity will be measured by the resistivity measurement unit 10 in the future. The camera 50 photographs the embankment surface S from above. More specifically, the camera 50 photographs the embankment surface S from vertically above or diagonally above. For example, when it is dark, such as at night, the camera 50 may photograph the embankment surface S illuminated by a light. In this case, a clearer image of the embankment surface S can be obtained.

[0040] In this embodiment, an example will be described in which portion B1 is a portion of embankment B whose resistivity has been measured by resistivity measurement unit 10. In this case, camera 50 photographs embankment surface S of embankment B whose resistivity has been measured by resistivity measurement unit 10 moving along movement direction D1. Camera 50 moves along movement direction D1 together with resistivity measurement unit 10 on the opposite side of resistivity measurement unit 10 from movement direction D1.

[0041] The camera 50 is attached to the rear side of the resistivity measurement unit 10. For example, the camera 50 photographs the embankment B while moving in the moving direction D1 together with the resistivity measurement unit 10. As an example, the camera 50 is attached to the rear end of the holder 11 located behind the resistivity measurement unit 10.

[0042] However, the placement position and placement manner of the camera 50 are not limited to the above example. Although the above describes an example in which the camera 50 moves in conjunction with the resistivity measurement unit 10, the camera 50 may be provided separately from the resistivity measurement unit 10. The camera 50 may be mounted on a vehicle separate from the resistivity measurement unit 10, or may be a camera mounted on a mobile terminal. The camera 50 may also be a camera mounted on a drone. In this case, the embankment B may be photographed by the camera 50 while the drone is flying over the embankment B.

[0043] The camera 50 may be a camera with a depth sensor that captures a depth-added image of the embankment B. A depth-added image is an image in which a depth in the Z direction is added to each pixel of a two-dimensional image in the XY direction, which corresponds to the horizontal direction. In a camera with a depth sensor, the distance sensor is held so that it faces the same direction as the digital camera. The distance sensor is, for example, a LiDAR (Light Detection and Ranging). The LiDAR irradiates the embankment B with a laser beam while switching the angle and detects the reflected light from the embankment B. From the detected round-trip time and irradiation angle of the laser beam, the distance Z to multiple irradiation points on the embankment surface S and the two-dimensional coordinates (X, Y) are obtained, i.e., the three-dimensional coordinates (X, Y, Z) of the multiple irradiation point clouds. If the camera 50 is a camera with a depth sensor, the gravel ratio (described later) can be calculated with higher accuracy. However, the type of camera 50 is not particularly limited.

[0044] The resistivity measuring unit 10, moisture meter 20, and camera 50 are capable of communicating with the data collecting unit 60. The resistivity of embankment B measured by the resistivity measuring unit 10, the volumetric water content measured by the moisture meter 20, and the image of embankment B taken by the camera 50 are transmitted to the data collecting unit 60.

[0045] The data collection unit 60 has, as its functional configuration, an image acquisition unit 61, a resistivity determination unit 62, a gravel ratio calculation unit 63, a quality evaluation unit 64, a position acquisition unit 65, a display control unit 66, and a memory unit 67. The image acquisition unit 61 acquires an image of the embankment B photographed by the camera 50.

[0046] The resistivity determination unit 62 acquires and determines the resistivity of embankment B measured by the resistivity measurement unit 10. Fig. 4 is a diagram showing an outline of the resistivity measurement unit 10. Fig. 5 is a diagram showing a schematic configuration of the electrodes 40 of the resistivity measurement unit 10. The resistivity measurement unit 10 measures the resistivity of embankment B at site A while moving across the embankment surface S after it has been compacted by a compaction machine.

[0047] The resistivity measuring unit 10 is equipped with four electrodes 40, which are capacitor electrodes. For example, the arrangement of the electrodes 40 in the resistivity measuring unit 10 conforms to the dipole-dipole method. The resistivity measuring unit 10 measures the resistivity of the embankment B using the four-electrode method. Each of the potential electrode 41 and the current electrode 42 is positioned so as to be close to the embankment surface S.

[0048] The pair of potential electrodes 41 and the pair of current electrodes 42 are arranged so as to be aligned along the movement direction D1 of the resistivity measurement unit 10. In this embodiment, the direction in which the multiple electrodes 40 are aligned coincides with the movement direction D1 of the resistivity measurement unit 10. In this manner, the relationship between the direction in which the multiple electrodes 40 are aligned and the movement direction D1 is preliminarily established. The measurement range (portion B1) of the resistivity measurement unit 10 is not at point P but extends over a certain range.

[0049] As an example, a pair of potential electrodes 41 are arranged on the rear side of the resistivity measuring unit 10, and a pair of current electrodes 42 are arranged on the front side of the resistivity measuring unit 10. For example, the pair of potential electrodes 41 and the pair of current electrodes 42 are arranged in a dipole-dipole configuration. However, the pair of potential electrodes 41 and the pair of current electrodes 42 may be arranged in a configuration other than the dipole-dipole configuration, and are not particularly limited.

[0050] The potential electrode 41 and the current electrode 42 are dragged, for example, on the raised surface S. Each of the potential electrode 41 and the current electrode 42 has a dielectric 43 facing the raised surface S and a conductor 44 electrically connected to the dielectric 43. The dielectric 43 is, for example, a plate-like member made of synthetic resin.

[0051] Since the dielectric 43 is in contact with the raised surface S and is dragged over the raised surface S, it is desirable that the dielectric 43 be made of a material that can withstand contact with the raised surface S. The dielectric 43 includes, for example, at least one of high-density polyethylene, hard polyurethane, and ABS (Acrylonitrile Butadiene Styrene).

[0052] The conductor 44 is a flat plate containing a conductive metal. The resistivity measuring unit 10 further includes an AC power supply 45 and an electrometer 46. The AC power supply 45 is electrically connected to the conductor 44 of each current electrode 42. The electrometer 46 is electrically connected to the conductor 44 of each potential electrode 41.

[0053] The AC power supply 45 applies an AC voltage between the pair of current electrodes 42. This causes an AC current to flow through the embankment B. For example, when a voltage is applied to the conductor 44 of the pair of current electrodes 42 that are not in contact with the embankment surface S, an electric charge accumulates between the conductor 44 and the embankment B, and the current electrode 42 becomes a capacitor. If the AC power supply 45 switches the polarity of the voltage before the current electrode 42, which has become a capacitor, is completely charged or discharged, an AC current will flow continuously through the embankment B, which has a resistance value. The electrometer 46 measures the electric potential between the pair of potential electrodes 41, which have become capacitors in the same way as the current electrodes 42.

[0054] Generally, the resistivity of embankment B decreases as the density (compacted density) of embankment B increases, and increases as the density of embankment B decreases. However, even if the density of embankment B is not low, the resistivity may increase if gravel is concentrated and exposed on the embankment surface S, causing unevenness on the embankment surface S.

[0055] If the density of the embankment B is low, the quality of the embankment B is not good. However, if gravel is concentrated and exposed on the embankment surface S, causing unevenness on the embankment surface S, the unevenness of the embankment surface S will prevent the electrode 40 from adhering to the embankment surface S, resulting in a high resistivity. In other words, the lack of adhesion between the electrode 40 and the embankment surface S will result in an apparently high measured resistivity. Therefore, it is conceivable that a state in which gravel is concentrated on the embankment surface S will be mistakenly determined to be of poor quality.

[0056] The embankment evaluation system 1 according to this embodiment can suppress the above-mentioned erroneous judgment. As shown in FIG. 3, the resistivity judgment unit 62 judges whether the resistivity measured by the resistivity measurement unit 10 is equal to or greater than a resistivity threshold. The "resistivity threshold" is a value that indicates the boundary between whether the measured resistivity is a value that may be problematic or not. For example, when the resistivity measured by the resistivity measurement unit 10 is equal to or greater than the resistivity threshold, there may be a problem with the quality of embankment B, and when the resistivity measured by the resistivity measurement unit 10 is not equal to or greater than the resistivity threshold, there is no problem with the quality of embankment B.

[0057] For example, the camera 50 photographs a portion of the embankment B whose resistivity has been determined to be equal to or greater than the resistivity threshold value by the resistivity determination unit 62. When the resistivity determination unit 62 determines that the resistivity is equal to or greater than the resistivity threshold value, the resistivity determination unit 62 may output a photographing signal to the camera 50, causing the camera 50 to photograph the embankment surface S.

[0058] The gravel ratio calculation unit 63 calculates the gravel ratio of embankment B from the image acquired by the image acquisition unit 61. The "gravel ratio" indicates the proportion of soil in embankment B whose particle size is equal to or greater than the gravel ratio threshold. The "gravel ratio threshold" is a value indicating the boundary between whether or not the quality of embankment B can be judged to be good. For example, if the calculated gravel ratio is equal to or greater than the gravel ratio threshold, the quality of embankment B is judged to be good, and if the calculated gravel ratio is less than the gravel ratio threshold, it is judged that the quality of embankment B may not be good. For example, the gravel ratio threshold is 37.5 mm or greater. However, the gravel ratio threshold can be changed as appropriate.

[0059] The gravel ratio calculation unit 63 calculates the gravel ratio of the embankment B from an image of the embankment B photographed by the camera 50. The gravel ratio calculation unit 63 calculates the gravel ratio by AI processing, for example, from an image of the embankment surface S photographed by the camera 50. In this case, the gravel ratio calculation unit 63 detects soil particles of the embankment B from the photographed image of the embankment surface S, and calculates the particle size of each of the detected soil particles.

[0060] The gravel ratio calculation unit 63 may calculate the gravel ratio as a granularity index. In this case, the gravel ratio calculation unit 63 identifies the contours of soil particles from the image of the embankment B photographed by the camera 50 and acquired by the image acquisition unit 61, extracts soil particles from the identified contours, and calculates the granularity index of the extracted soil particles as the gravel ratio.

[0061] Then, the gravel ratio calculation unit 63 calculates the gravel ratio as the ratio of the number of soil particles whose calculated particle size is equal to or larger than the gravel ratio threshold to the number of detected soil particles. For example, the gravel ratio calculation unit 63 calculates the gravel ratio every time the camera 50 photographs the mound surface S. The gravel ratio calculated by the gravel ratio calculation unit 63 is stored in the memory unit 67.

[0062] The quality evaluation unit 64 evaluates the quality of the embankment B using the resistivity measured by the resistivity measurement unit 10 and the image of the embankment B taken by the camera 50. For example, the quality evaluation unit 64 evaluates that the quality of the embankment B is good when the resistivity determination unit 62 determines that the resistivity is equal to or greater than the resistivity threshold value and the gravel ratio calculated by the gravel ratio calculation unit 63 is equal to or greater than the gravel ratio threshold value.

[0063] The quality evaluation unit 64 may calculate the density of embankment B from the resistivity measured by the resistivity measurement unit 10 and the volumetric moisture content measured by the moisture meter 20. For example, the quality evaluation unit 64 may calculate at least one of the density of embankment B and the moisture content of embankment B as an evaluation item of embankment B. The quality evaluation unit 64 evaluates embankment B by measuring the density and moisture content of embankment B, and measures, for example, the effect of compaction by a compaction machine.

[0064] The position acquisition unit 65 acquires the position of the embankment evaluation system 1 as position information. As an example, the position acquisition unit 65 may be a GNSS antenna. The position acquisition unit 65 links the resistivity acquired by the resistivity measurement unit 10 to the acquired position information. The position acquisition unit 65 links the volumetric moisture content acquired by the moisture meter 20 to the acquired position information.

[0065] The position acquisition unit 65 links the image acquired by the image acquisition unit 61 with the acquired position information. The position acquisition unit 65 links the gravel ratio calculated by the gravel ratio calculation unit 63 with the acquired position information. The position acquisition unit 65 may also link the results of evaluation by the quality evaluation unit 64 with the position information. The position acquisition unit 65 links at least one of the resistivity, volumetric water content, image of embankment B, gravel ratio, and quality evaluation results (also referred to as "measurement data" in this embodiment) with the acquired position information.

[0066] The display control unit 66 controls the display by the display unit 70. The display control unit 66 displays, for example, resistivity, volumetric water content, an image of embankment B, gravel ratio, and quality assessment results along with location information. FIG. 6 shows an example of a screen displayed on the display unit 70 by the display control unit 66. As shown in FIG. 6, the display control unit 66 displays measurement data for each piece of location information acquired by the position acquisition unit 65 on the display 71 of the display unit 70. In the embankment evaluation system 1, the site A is divided into a plurality of mesh areas 72, and the position acquisition unit 65 associates measurement data for each area 72. The display control unit 66 displays the measurement data associated with each area 72 on the display 71 of the display unit 70.

[0067] Fig. 6 shows an example in which the display control unit 66 displays the density calculated by the quality evaluation unit 64 as a map (heat map) on the display 71. In the example of Fig. 6, areas 72 with high density are displayed in dark colors, and areas 72 with low density are displayed in light colors. As shown in Fig. 6, by displaying the density of embankment B for each area 72, the quality of embankment B can be visually displayed.

[0068] The display unit 70 displays the gravel ratio calculated by the gravel ratio calculation unit 63 together with the density. As an example, when a cursor 73 is moved to an area 72 on the display 71, the gravel ratio of that area 72 is displayed as a speech bubble 74. In this case, both the density and the gravel ratio can be ascertained by looking at the display 71. However, the gravel ratio does not have to be displayed as a speech bubble 74 on the display 71, and the gravel ratio for each area 72 may be displayed as a map. Furthermore, at least one of the resistivity and the volumetric water content may be displayed as a map for each area 72.

[0069] The memory unit 67 stores the measurement data. The memory unit 67 may be a database installed in the information terminal. For example, the memory unit 67 stores an image of the embankment surface S taken by the camera 50, linking it to the position information acquired by the position acquisition unit 65. The memory unit 67 may store in advance the relationship between the resistivity of the embankment B and the density of the embankment B.

[0070] Next, an example of the steps of the embankment evaluation method according to this embodiment will be described. Fig. 7 is a flowchart showing an example of the steps of the embankment evaluation method. Below, an example of a method for evaluating embankment B using embankment evaluation system 1 will be described. First, as shown in Fig. 1, a moisture meter 20 and a resistivity measurement unit 10 are connected to a traction unit 30 via linear bodies 2, 3, and 4, and the resistivity measurement unit 10 and the moisture meter 20 are moved over embankment B by moving the traction unit 30 in a moving direction D1 (step of moving the embankment evaluation system).

[0071] The resistivity measuring unit 10 measures the resistivity of embankment B (step of measuring resistivity, step S1). At this time, the pair of potential electrodes 41 and the pair of current electrodes 42 measure the resistivity of embankment B while facing embankment B. The moisture meter 20 also measures the volumetric water content of embankment B (step of measuring volumetric water content, step S2). For example, the measurement of the volumetric water content by the moisture meter 20 is carried out simultaneously with the measurement of resistivity by the resistivity measuring unit 10. The resistivity measuring unit 10 and the moisture meter 20 each measure the resistivity and the volumetric water content while traveling over embankment B.

[0072] As shown in Figure 2, the camera 50 photographs the embankment B for which resistivity measurement has been performed by the resistivity measurement unit 10. At this time, the camera 50 photographs a portion B1 of the embankment B for which resistivity has been measured in the process of measuring resistivity. For example, the camera 50 moves in a moving direction D1 together with the resistivity measurement unit 10, and photographs the embankment B for which resistivity has been measured while moving in the moving direction D1. The image of the embankment B photographed by the camera 50 is output to the data collection unit 60.

[0073] At this time, the image acquisition unit 61 acquires the image captured by the camera 50, and, for example, the image acquired by the image acquisition unit 61 is stored in the memory unit 67. Then, the gravel ratio calculation unit 63 calculates the gravel ratio of the embankment B from the image of the embankment B captured by the camera 50 (step of calculating the gravel ratio, step S3).

[0074] As described above, in calculating the gravel ratio by the gravel ratio calculation unit 63, the gravel ratio calculation unit 63 detects soil particles from the image of the embankment B. Then, the gravel ratio calculation unit 63 calculates the particle size of each detected soil particle, and calculates the gravel ratio as the ratio of the number of soil particles whose particle size is equal to or greater than the gravel ratio threshold to the number of detected soil particles.

[0075] For example, the quality evaluation unit 64 calculates the density of the embankment B using the resistivity, gravel ratio, and volumetric water content. The quality evaluation unit 64 calculates the density using a calibration curve X that shows the relationship between resistivity and density, which has been obtained in advance, as shown in Fig. 8. For example, multiple calibration curves X have been obtained in advance, and the quality evaluation unit 64 changes the type of calibration curve X depending on the calculated gravel ratio value.

[0076] The multiple calibration curves X are, for example, a first calibration curve X1 and a second calibration curve X2 that has a larger density value than the first calibration curve X1 when the resistivity values ​​are the same. For example, the quality evaluation unit 64 calculates the density using the second calibration curve X2 when the gravel rate calculated by the gravel rate calculation unit 63 is equal to or greater than the gravel rate threshold, and calculates the density using the first calibration curve X1 when the gravel rate calculated by the gravel rate calculation unit 63 is less than the gravel rate threshold. As a result, when the gravel rate is equal to or greater than the gravel rate threshold, the density is calculated to be higher than when the gravel rate is less than the gravel rate threshold.

[0077] For example, the quality evaluation unit 64 calculates the moisture content (step S5 of calculating the moisture content). The quality evaluation unit 64 calculates the moisture content from, for example, the volumetric moisture content, the density, and the weight of water per unit volume. The weight of water per unit volume is usually 1. For example, the calculation of density by the quality evaluation unit 64 and the calculation of moisture content by the quality evaluation unit 64 are performed continuously while the embankment evaluation system 1 (resistivity measurement unit 10 and moisture meter 20) is traveling over the embankment B. In this case, it is possible to calculate the density and moisture content of the embankment B in a planar manner. For example, the density and moisture content may be calculated in association with the position information (for example, area 72) of the embankment B measured by the position acquisition unit 65.

[0078] Next, the display unit 70 displays the measurement data on the display 71 (displaying step, step S6). As shown in Fig. 6, the display unit 70 may display the density as a map for each region 72. As described above, the display unit 70 may display the gravel ratio calculated by the gravel ratio calculation unit 63 together with the density.

[0079] Furthermore, the display unit 70 may display at least one of the gravel fraction, the resistivity, and the volumetric water content for each region 72. Also, the display 71 may be configured to be switchable between at least one of a screen displaying the density, a screen displaying the gravel fraction, a screen displaying the resistivity, and a screen displaying the volumetric water content.

[0080] Furthermore, the quality evaluation unit 64 judges the quality of the embankment B using the resistivity measured in the resistivity measuring step and the image of the embankment B photographed in the photographing step (a quality determining step). For example, the quality evaluation unit 64 judges that the quality of the embankment B whose density is equal to or greater than a certain value is good, and judges that the quality of the embankment B whose density is less than the certain value is not good.

[0081] For example, if the quality assessment performed by the quality assessment unit 64 determines that the quality of embankment B is good for all areas 72, the series of steps in the embankment assessment method is completed. On the other hand, if it is determined that there is an area 72 where the quality of embankment B is not good, at least one of re-measuring the resistivity of embankment B and compacting the embankment B is performed (step of performing at least one of re-measuring and compacting).

[0082] In the re-measurement, for example, the embankment evaluation system 1 is run over the embankment B again, the resistivity measurement unit 10 measures the resistivity, and the moisture meter 20 measures the volumetric water content, and the above-mentioned steps S1 to S6 are executed again. In the compaction, the embankment surface S of the embankment B is compacted again by a compaction machine. With the above steps, the series of steps in the embankment evaluation method is completed.

[0083] Next, the effects obtained from the embankment evaluation system 1 and embankment evaluation method according to this embodiment will be described in detail. In the embankment evaluation system 1 and embankment evaluation method according to this embodiment, the resistivity measurement unit 10 measures the resistivity of the embankment B with a pair of potential electrodes 41 and a pair of current electrodes 42 facing the embankment B. The resistivity measurement unit 10 measures the resistivity of the embankment B while being towed by the towing unit 30. The embankment evaluation system 1 is equipped with a camera 50, which photographs a portion B1 of the embankment B where the resistivity is to be measured. A quality evaluation unit 64, which evaluates the quality of the embankment B, uses the resistivity measured by the resistivity measurement unit 10 and the image of the embankment B photographed by the camera 50.

[0084] Therefore, the quality of embankment B is evaluated not only from the resistivity but also from the image of embankment B on which the resistivity is measured. By acquiring an image of embankment B, the actual condition of embankment B can be grasped, and by adjusting the resistivity value measured using the image (for example, using the second calibration curve X2 instead of the first calibration curve X1), it is possible to avoid measuring the resistivity as high when the density is not actually low. Therefore, it is possible to avoid measuring the density as low when the density is not actually low, and to prevent the quality of embankment B from being erroneously evaluated as poor. As a result, the accuracy of the quality evaluation of embankment B can be improved.

[0085] In this embodiment, the resistivity measurement unit 10 is moved along the movement direction D1 by the towing unit 30, and the camera 50 may move along the movement direction D1 together with the resistivity measurement unit 10 on the opposite side (rear side) of the resistivity measurement unit 10 from the movement direction D1. In this case, when the resistivity measurement unit 10 moves forward, the camera 50 is positioned rearward of the resistivity measurement unit 10. The camera 50 then moves along the movement direction D1 together with the resistivity measurement unit 10 behind the resistivity measurement unit 10. Therefore, resistivity measurement and photography of the embankment B can be performed while towing, allowing efficient evaluation of the embankment B.

[0086] In this embodiment, the embankment evaluation system 1 includes a resistivity determination unit 62 that determines whether the resistivity measured by the resistivity measurement unit 10 is equal to or greater than the resistivity threshold. The camera 50 photographs the portion of the embankment B whose resistivity has been determined to be equal to or greater than the resistivity threshold by the resistivity determination unit 62. In this case, the camera 50 can photograph only the portion of the embankment B whose resistivity is equal to or greater than the resistivity threshold, so that the number of photographs taken by the camera 50 can be kept to a minimum.

[0087] In this embodiment, the embankment evaluation system 1 includes a resistivity determination unit 62 that determines whether the resistivity measured by the resistivity measurement unit 10 is equal to or greater than a resistivity threshold, and a gravel ratio calculation unit 63 that calculates the gravel ratio of embankment B from an image of embankment B captured by camera 50. The quality evaluation unit 64 may evaluate the quality of embankment B as good when the resistivity determination unit 62 determines that the resistivity is equal to or greater than the resistivity threshold and the gravel ratio calculated by the gravel ratio calculation unit 63 is equal to or greater than the gravel ratio threshold. In this case, it is possible to prevent an erroneous evaluation that the quality of embankment B, whose gravel ratio is equal to or greater than the gravel ratio threshold, is poor. This further improves the accuracy of the quality evaluation of embankment B.

[0088] In this embodiment, the embankment evaluation system 1 includes a gravel ratio calculation unit 63 that calculates the gravel ratio of embankment B from an image of embankment B captured by a camera 50, and a moisture meter 20 that faces embankment B and measures the volumetric water content of embankment B. A quality evaluation unit 64 calculates the density of embankment B from the resistivity measured by the resistivity measurement unit 10 and the volumetric water content measured by the moisture meter 20. The embankment evaluation system 1 further includes a display unit 70 that displays the gravel ratio calculated by the gravel ratio calculation unit 63 together with the density. In this case, the gravel ratio is displayed on the display unit 70 along with the density, allowing the results of the quality evaluation to be visually understood on the display unit 70.

[0089] In this embodiment, the embankment evaluation system 1 is equipped with a moisture meter 20 that measures the volumetric moisture content of the embankment B while facing the embankment B, and the moisture meter 20 is a scattering-type RI moisture meter. In this case, the volumetric moisture content can be measured with higher accuracy, which further improves the accuracy of the quality evaluation of the embankment B.

[0090] In this embodiment, the embankment evaluation method further includes, when the quality of the embankment B is determined to be poor in the step of determining the quality of the embankment B, a step of at least one of re-measuring the resistivity of the embankment B and compacting the embankment B. In this case, at least one of re-measuring and compacting is performed on the embankment B whose quality has been determined to be poor, so it is possible to further improve the quality of the embankment B.

[0091] The above describes embodiments of the embankment evaluation system and embankment evaluation method according to the present disclosure. However, the present disclosure is not limited to the above-described embodiments, and may be modified within the scope of the gist of the claims. In other words, the function, configuration, shape, size, material, number, and arrangement of each part of the embankment evaluation system, as well as the content and order of the steps of the embankment evaluation method, may be modified as appropriate within the scope of the above-described gist.

[0092] For example, in the above-described embodiment, the embankment evaluation system 1 has been described as having a moisture meter 20. However, if the embankment B is CSG, the embankment evaluation system may not have a moisture meter 20. Furthermore, in the above-described embodiment, the embankment evaluation system 1 has been described as having a data collection unit 60 that has an image acquisition unit 61, a resistivity determination unit 62, a gravel ratio calculation unit 63, a quality evaluation unit 64, a position acquisition unit 65, a display control unit 66, and a memory unit 67. However, the embankment evaluation system may have a data collection unit that does not have any of the image acquisition unit 61, the resistivity determination unit 62, the gravel ratio calculation unit 63, the quality evaluation unit 64, the position acquisition unit 65, the display control unit 66, and the memory unit 67.

[0093] In the above-described embodiment, an example has been described in which the quality evaluation unit 64 determines that the quality of the embankment B is good when the resistivity determined by the resistivity determination unit 62 is determined to be equal to or greater than the resistivity threshold value and the gravel ratio calculated by the gravel ratio calculation unit 63 is equal to or greater than the gravel ratio threshold value. However, the quality evaluation unit may determine the quality of the embankment B using an index other than the gravel ratio in the image. In other words, the quality evaluation unit may evaluate the quality of the embankment B from the resistivity measured by the resistivity measurement unit 10 and the image of the embankment B captured by the camera 50 itself. [Explanation of symbols]

[0094] 1...embankment evaluation system, 2, 3, 4...linear body, 10...resistivity measurement unit, 11...holding body, 12...caster, 13...electrode holding unit, 16...spring mechanism, 20...moisture meter, 21...moisture measurement unit, 22...traveling body, 22b...wheel, 22c...base, 23...holding unit, 30...traction unit, 30b...wheel, 30c...connecting unit, 40...electrode, 41...potential electrode, 42...current electrode, 43...dielectric, 44...conductor, 45...AC power source, 46...potential meter , 50...camera, 60...data collection unit, 61...image acquisition unit, 62...resistivity determination unit, 63...gravel ratio calculation unit, 64...quality evaluation unit, 65...position acquisition unit, 66...display control unit, 67...memory unit, 70...display unit, 71...display, 72...area, 73...cursor, 74...balloon, A...site, B...embankment, B1...part, D1...movement direction, D2...direction, S...embankment elevation, X...calibration curve, X1...first calibration curve, X2...second calibration curve.

Claims

1. a resistivity measuring unit having a pair of potential electrodes and a pair of current electrodes that measure the resistivity of the embankment while facing the embankment; a towing unit that moves the resistivity measuring unit in the embankment; a camera that photographs a portion of the embankment whose resistivity is to be measured by the resistivity measuring unit; a quality evaluation unit that evaluates the quality of the embankment using the resistivity measured by the resistivity measurement unit and the image of the embankment taken by the camera; and Equipped with Embankment evaluation system.

2. The resistivity measuring unit is moved along the movement direction by the towing unit, the camera moves along the movement direction together with the resistivity measurement unit on the opposite side of the movement direction from the resistivity measurement unit; The embankment evaluation system according to claim 1 .

3. a resistivity determination unit that determines whether the resistivity measured by the resistivity measurement unit is equal to or greater than a resistivity threshold value, The camera photographs a portion of the embankment whose resistivity is determined by the resistivity determination unit to be equal to or greater than a resistivity threshold. The embankment evaluation system according to claim 1 or 2.

4. a resistivity determination unit that determines whether the resistivity measured by the resistivity measurement unit is equal to or greater than a resistivity threshold; a gravel ratio calculation unit that calculates the gravel ratio of the embankment from the image of the embankment taken by the camera, The quality evaluation unit evaluates the quality of the embankment as good when the resistivity determination unit determines that the resistivity is equal to or greater than a resistivity threshold value and the gravel ratio calculated by the gravel ratio calculation unit is equal to or greater than a gravel ratio threshold value. The embankment evaluation system according to claim 1 or 2.

5. a gravel ratio calculation unit that calculates the gravel ratio of the embankment from the image of the embankment captured by the camera; a moisture meter that measures the volumetric moisture content of the embankment while facing the embankment, The quality evaluation unit calculates the density of the embankment from the resistivity measured by the resistivity measurement unit and the volumetric water content measured by the moisture meter, a display unit that displays the gravel ratio calculated by the gravel ratio calculation unit together with the density, The embankment evaluation system according to claim 1 or 2.

6. a moisture meter facing the embankment to measure the volumetric moisture content of the embankment; The moisture meter is a scattering type RI moisture meter. The embankment evaluation system according to claim 1 or 2.

7. measuring the resistivity of the embankment with a pair of potential electrodes and a pair of current electrodes facing the embankment; a step of photographing a portion of the embankment whose resistivity is measured in the step of measuring the resistivity; a step of determining the quality of the embankment using the resistivity measured in the step of measuring the resistivity and the image of the embankment taken in the step of taking the photograph; Equipped with Embankment evaluation methods.

8. The method further comprises a step of performing at least one of re-measuring the resistivity of the embankment and compacting the embankment when the quality of the embankment is determined to be poor in the step of determining the quality of the embankment. The method for evaluating embankments according to claim 7.

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