Resistivity measuring apparatus and embankment evaluating method

Abstract

To provide a specific resistance measuring device and a banking evaluation method capable of preventing an electrode from being damaged.SOLUTION: This specific resistance measuring instrument includes an electrode-housing part 5 for housing potential electrodes and current electrodes, and a traveling body 3 having a plurality of rolling body 3b parts for supporting the electrode-housing part 5 and rolling on the banking S, and traveling along a traveling direction D1 part together with the electrode-housing part 5 in the banking S. The electrode-housing part 5 has a bottom part side 5b in contact with the banking S, and an inclined part side 5b extending obliquely upward from an end part on the D1 side in the advancing direction of the bottom part side 5c. The end portion of the inclined portion 5c on the traveling direction D1 side is located on the side opposite to the traveling direction D1 with respect to the end portions of the plurality of rolling elements 3b on the traveling direction D1 side.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a resistivity measuring device for measuring the resistivity of an embankment, and a method for evaluating an embankment. [Background technology]

[0002] Patent Document 1 describes a ground surface measurement system. The measurement system includes a sled-equipped measurement device having a radiation source unit, a fast neutron detection unit, a thermal neutron detection unit, a gamma ray detection unit, a data processing device unit, a peripheral device unit, and a steel sled. The steel sled is formed by processing a single smooth steel plate into a curved surface so that it can be towed by a towing vehicle and move in close contact with the ground. The sled-equipped measurement device is towed by a traveling vehicle to a target location and performs porosity measurement, moisture measurement, and density measurement. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 2751839 Summary of the Invention [Problem to be solved by the invention]

[0004] A resistivity measuring device is known that measures the resistivity of an embankment using a pair of potential electrodes and a pair of current electrodes that function as capacitor electrodes. In this resistivity measuring device, the pair of potential electrodes and the pair of current electrodes are brought into contact with the embankment, and the resistivity measuring device is moved by a traveling vehicle while measuring the resistivity of the embankment.

[0005] However, embankments can have unevenness, which can increase the distance between the electrodes and the embankment. When the distance between the electrodes and the embankment increases, it becomes more difficult to pass current through the embankment, potentially resulting in measurement errors. To address this issue, a resistivity measuring device equipped with a spring mechanism that presses the electrodes against the embankment is known. In this resistivity measuring device, the spring mechanism presses the electrodes against the embankment, reducing the effect of unevenness and improving the accuracy of resistivity measurements.

[0006] However, embankments can have unevenness, such as ruts left by the vibratory rollers that compact the embankment. Furthermore, the vibratory rollers move along each of multiple rolling lanes to perform compaction, and unevenness can occur between two adjacent rolling lanes. Therefore, there is a concern that the electrodes may get caught on the unevenness and be damaged as the traveling body moves along the embankment.

[0007] The present disclosure aims to provide a resistivity measuring device and an embankment evaluation method that can prevent electrodes from being damaged. [Means for solving the problem]

[0008] (1) A resistivity measuring device according to the present disclosure is a resistivity measuring device having a pair of potential electrodes and a pair of current electrodes that face the embankment and measure the resistivity of the embankment. The resistivity measuring device includes an electrode housing that houses the potential electrodes and the current electrodes, respectively, and a traveling body that supports the electrode housing and has a plurality of rolling elements that roll on the embankment and travels in the direction of travel together with the electrode housing on the embankment. The electrode housing has a bottom that contacts the embankment and a sloped portion that extends obliquely upward from the end of the bottom facing the direction of travel. The end of the sloped portion facing the direction of travel is located on the opposite side of the direction of travel from the ends of the rolling elements facing the direction of travel.

[0009] This resistivity measuring device measures the resistivity of an embankment with a pair of potential electrodes and a pair of current electrodes facing the embankment. The potential electrodes and the current electrodes are each housed in an electrode housing. Therefore, the potential electrodes and the current electrodes can be protected by the electrode housing. The resistivity measuring device has a traveling body with multiple rolling elements. The multiple rolling elements roll on the embankment, causing the traveling body to travel along the direction of travel together with the electrode housing. The electrode housing has a sloped portion extending obliquely upward from the end of the bottom of the electrode housing on the traveling direction side. The sloped portion of the electrode housing on the traveling direction side makes it easier for the electrode housing to overcome unevenness. Furthermore, the end of the sloped portion of the electrode housing on the traveling direction side is located on the opposite side of the traveling direction from the end of the rolling elements on the traveling direction side. Therefore, when the traveling body travels, the rolling elements come into contact with a step before the sloped portion of the electrode housing. This reduces the possibility of the electrode housing part coming into contact with a step, thereby preventing damage to the electrode.

[0010] (2) In (1) above, the multiple rolling elements may include two front wheels positioned on the traveling direction side of the traveling element and two rear wheels positioned on the opposite side of the traveling direction of the traveling element from the two front wheels. The resistivity measuring device may be equipped with a front wheel steering mechanism that interlocks the two front wheels. In this case, by providing a front wheel steering mechanism that interlocks the two front wheels, the turning radius of the traveling element when turning can be reduced. Therefore, the traveling element can easily move to the next compaction lane by turning.

[0011] (3) In the above (1) or (2), the resistivity measuring device may have a spring mechanism provided corresponding to each of the plurality of electrode housings, which biases each electrode housing toward the embankment. In this case, the electrode housings, which hold the pair of potential electrodes and the pair of current electrodes facing the embankment, are biased toward the embankment by the spring mechanism. Therefore, the pair of potential electrodes and the pair of current electrodes are biased by the spring mechanism so as to be pressed against the embankment, so that each potential electrode and each current electrode can follow the embankment even if there is unevenness. This makes it possible to measure the resistivity of the embankment easily and with high accuracy.

[0012] (4) In any of (1) to (3) above, the inclined portion may extend in a cross direction that crosses the traveling direction. The electrode accommodating portion may have a pair of side inclined portions extending in the opposite direction to the traveling direction from both ends of the inclined portion in the cross direction. In this case, by providing a pair of side inclined portions that extend diagonally upward as they move away from the bottom, the electrode can be more reliably protected even when the traveling body travels diagonally with respect to the traveling direction.

[0013] (5) In any of the above (1) to (4), the potential electrode and the current electrode may each be placed on the bottom of the electrode housing, and the bottom may be detachable from the inclined portion. In this case, the bottom and the electrode can be detached from the inclined portion in the electrode housing. Therefore, even if the bottom or the electrode that contacts the embankment breaks down, it is possible to replace only the bottom or only the electrode. This reduces the need to replace the entire electrode housing, thereby suppressing increases in the cost of the electrode housing.

[0014] (6) A method for evaluating embankments according to the present disclosure is a method for evaluating the quality of an embankment using the resistivity measurement device described above. The method for evaluating embankments includes the steps of measuring the resistivity of the embankment while traveling a traveling body supporting electrode housings that house potential electrodes and current electrodes in the embankment in a traveling direction, calculating the density of the embankment from the resistivity, and determining the quality of the embankment from the density. This method for evaluating embankments includes the resistivity measurement device described above, and therefore achieves the same effects as the resistivity measurement device described above. [Effects of the Invention]

[0015] According to the present disclosure, damage to the electrodes can be prevented. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view showing a resistivity measuring device according to an embodiment. [Figure 2] 2(a) and 2(b) are diagrams that schematically show the measurement of resistivity using the resistivity measuring device of FIG. [Figure 3] FIG. 3 is a plan view showing a resistivity measuring device moving along a rolling lane. [Figure 4] FIG. 4 is a diagram for explaining the conditions for each part of the traveling body and the electrode housing part to overcome the step. [Figure 5] FIG. 5 is a perspective view showing the traveling body and the electrode housing portion according to the embodiment. [Figure 6] FIG. 6 is a perspective view showing an electrode and an electrode housing portion according to the embodiment. [Figure 7] Fig. 7(a) is a perspective view of the electrode accommodating section of Fig. 6 when viewed from above, Fig. 7(b) is a rear view of the electrode accommodating section of Fig. 6, and Fig. 7(c) is a perspective view of the electrode accommodating section of Fig. 6 when viewed from the side. [Figure 8] FIG. 8 is a perspective view of the resistivity measuring device according to the first modified example, as viewed from below. [Figure 9] FIG. 9 is a plan view showing a resistivity measuring device according to the second modified example. [Figure 10] FIG. 10 is a perspective view showing an example of an embankment evaluation system for evaluating an embankment. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of a resistivity measuring device and an embankment evaluation method according to the present disclosure will be described with reference to the drawings. In the description of the drawings, identical 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.

[0018] The resistivity measuring device and embankment evaluation method according to this embodiment are used, for example, at a site G where a dam is being constructed. At the site G, as an example, earth and sand are transported by a dump truck, the transported earth and sand are spread and leveled by a bulldozer, and the spread and leveled earth and sand are compacted by a vibrating roller. The vibrating roller compacts the embankment S, which is the ground material, by traveling back and forth multiple times along a compaction lane at the site G.

[0019] For example, the resistivity measuring device 1 evaluates the embankment S at the construction site G while traveling over the embankment surface S1, which is a compacted surface after being compacted by a compaction machine such as a vibrating roller. In this embodiment, the embankment surface S1 corresponds to the surface to be evaluated by the resistivity measuring device 1. The embankment surface S1 is a construction surface formed by compaction. The resistivity measuring device 1, for example, calculates the density of the embankment S as an evaluation item for the embankment S. In this embodiment, the density is at least one of a dry density and a wet density.

[0020] For example, the resistivity measuring device 1 evaluates the embankment S by measuring the density of the embankment S and measures the effect of compaction by a compaction machine. The embankment S is, for example, CSG (Cemented Sand and Gravel). However, the embankment S may also be RCD (Roller Compacted Dam Concrete), and the type of embankment S is not particularly limited.

[0021] For example, the resistivity measurement device 1 according to this embodiment is a portable device. The resistivity measurement device 1 has, for example, a towing unit 2. The resistivity measurement device 1 moves along a traveling direction D1 due to the towing of the towing unit 2. Hereinafter, the traveling direction D1 may be referred to as the front, front side, or forward, and the direction opposite to the traveling 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 an object.

[0022] As an example, the towing unit 2 has a plurality of wheels 2b and a connecting portion 2c that connects the upper portions of the plurality of wheels 2b together. The towing unit 2 may be, for example, a vehicle that has a seat and can be driven while sitting in the seat. The resistivity measuring device 1 has a running body 3 that moves along a traveling direction D1 and a linear body 6b that extends from the towing unit 2 to the running body 3. The connecting portion 2c of the towing unit 2 is connected to the running body 3 via the linear body 6b. With the plurality of wheels 2b placed on the banking surface S1, which is the upper surface of the embankment S, the plurality of wheels 2b roll on the banking surface S1, allowing the towing unit 2 and the running body 3 to move along the traveling direction D1 on the banking surface S1.

[0023] FIG. 2(a) is a side view showing the resistivity measuring device 1. FIG. 2(b) is a diagram for explaining measurement of resistivity using the resistivity measuring device 1. As shown in FIGS. 1, 2(a), and 2(b), the resistivity measuring device 1 includes a plurality of electrodes 4, an electrode housing unit 5 that houses the electrodes 4, and a traveling body 3 that supports the electrode housing unit 5. In FIG. 1, the electrode housing unit 5 is illustrated in a simplified manner. The plurality of electrodes 4 are a pair of potential electrodes 4b and a pair of current electrodes 4c. The resistivity measuring device 1 has a pair of potential electrodes 4b and a pair of current electrodes 4c that face the embankment S and measure the resistivity of the embankment S.

[0024] For example, the resistivity measuring device 1 has two traveling bodies 3 and a linear body 6c connecting the two traveling bodies 3 to each other. The traveling body 3 has a plurality of rolling bodies 3b that roll on the embankment S. The linear body 6c is, for example, detachable from the traveling body 3. When this linear body 6c is provided, when one of the two traveling bodies 3 (for example, the traveling body 3 having the electrode housing portion 5 that houses the current electrode 4c) is pulled in the traveling direction D1, both of the two traveling bodies 3 can be moved along the traveling direction D1.

[0025] By preparing a plurality of types of linear body 6c with different lengths and attaching a linear body 6c selected from the plurality of types of linear body 6c, the distance from potential electrode 4b to current electrode 4c can be changed, and therefore the depth at which resistivity is measured can be changed by changing the distance from potential electrode 4b to current electrode 4c.

[0026] The electrode housing 5 houses the potential electrode 4b and the current electrode 4c. The traveling body 3 travels in the embankment S together with the electrode housing 5 along the traveling direction D1. The resistivity measuring device 1 has a spring mechanism 7 provided corresponding to each of the multiple electrode housings 5, which urges each electrode housing 5 toward the embankment S. If the traveling body 3 travels and encounters an unevenness on the embankment surface S1, the electrode housing 5 comes into contact with the unevenness and the electrode 4 moves in the direction D2. The direction D2 is, for example, the vertical direction. Because the spring mechanism 7 urges the electrode 4 toward the embankment S, the electrode 4 can follow the unevenness even if there is an unevenness on the embankment surface S1.

[0027] The resistivity measuring device 1 includes, for example, a data collection unit 8 that collects measured resistivity and a display unit 9 that displays measurement data including the resistivity collected by the data collection unit 8. In FIG. 1, the illustration of the data collection unit 8 and the display unit 9 is simplified. As an example, the data collection unit 8 is an information terminal such as a personal computer. The data collection unit 8 is provided in the towing unit 2. However, the location of the data collection unit 8 is not particularly limited. The data collection unit 8 may be mounted on the bed of the towing unit 2, which is a vehicle. The data collection unit 8 may include a computer mounted on the towing unit 2 and a tablet terminal capable of communicating with the computer.

[0028] Furthermore, the data collection unit 8 may have a position acquisition unit that acquires the position of the resistivity measurement device 1 as position information. The position acquisition unit may be, for example, a GNSS antenna. The position acquisition unit associates the resistivity measured by the resistivity measurement device 1 with the acquired position information.

[0029] The display unit 9 is capable of communicating with the data collection unit 8. When the data collection unit 8 is a personal computer, the display unit 9 may be a display of the personal computer. The display unit 9 may also be a display of a mobile terminal (tablet terminal) capable of communicating with the data collection unit 8.

[0030] As an example, the display unit 9 is a display placed in front of the seat of the towing unit 2. In this case, the driver of the towing unit 2 can visually check the data measured by the data collection unit 8 while driving the towing unit 2. However, the form of the display unit 9 is not limited to the above example and can be changed as appropriate.

[0031] The resistivity measuring device 1 measures the resistivity of the embankment S at the site G while moving over the embankment surface S1 after it has been compacted by a compaction machine such as a vibrating roller. The resistivity measuring device 1 is equipped with four electrodes 4, which are capacitor electrodes. For example, the arrangement of the electrodes 4 in the resistivity measuring device 1 conforms to the dipole-dipole method. The resistivity measuring device 1 measures the resistivity of the embankment S using the four-electrode method. The potential electrode 4b and the current electrode 4c are each positioned close to the embankment surface S1.

[0032] The pair of potential electrodes 4b and the pair of current electrodes 4c are arranged so as to be aligned along the traveling direction D1 of the resistivity measuring device 1. In this embodiment, the direction in which the multiple electrodes 4 are aligned coincides with the traveling direction D1 of the resistivity measuring device 1. In this manner, the relationship between the direction in which the multiple electrodes 4 are aligned and the traveling direction D1 is preliminarily established. The measurement range of the resistivity measuring device 1 does not extend to point P but to a certain range E.

[0033] As an example, a pair of potential electrodes 4b are arranged on the rear side of the resistivity measuring device 1, and a pair of current electrodes 4c are arranged on the front side of the resistivity measuring device 1. For example, the pair of potential electrodes 4b and the pair of current electrodes 4c are arranged in a dipole-dipole configuration. However, the pair of potential electrodes 4b and the pair of current electrodes 4c may be arranged in a configuration other than the dipole-dipole configuration, and are not particularly limited.

[0034] The potential electrode 4b and the current electrode 4c are dragged, for example, on the raised surface S1. Each of the potential electrode 4b and the current electrode 4c has a dielectric 4d facing the raised surface S1 and a conductor 4f electrically connected to the dielectric 4d. The dielectric 4d is, for example, a plate-like member made of synthetic resin.

[0035] Since the dielectric 4d is dragged over the raised surface S1 while in contact with the raised surface S1, it is desirable that the dielectric 4d be made of a material that can withstand contact with the raised surface S1. The dielectric 4d includes, for example, at least one of high-density polyethylene, hard polyurethane, and ABS (Acrylonitrile Butadiene Styrene).

[0036] The conductor 4f is a flat plate containing a conductive metal. The resistivity measuring device 1 further includes an AC power supply 4h and an electrometer 4j. The AC power supply 4h is electrically connected to the conductor 4f of each current electrode 4c. The electrometer 4j is electrically connected to the conductor 4f of each potential electrode 4b.

[0037] The AC power supply 4h applies an AC voltage between the pair of current electrodes 4c. This causes an AC current to flow through the embankment S. For example, when a voltage is applied to the conductor 4f of the pair of current electrodes 4c that is not in contact with the embankment surface S1, an electric charge accumulates between the conductor 4f and the embankment S, and the current electrode 4c becomes a capacitor. If the AC power supply 4h switches the polarity of the voltage before the current electrode 4c that has become a capacitor is completely charged or discharged, an AC current will flow continuously through the embankment S, which has a resistance value. The electrometer 4j measures the electric potential between the pair of potential electrodes 4b that have become capacitors in the same way as the current electrode 4c.

[0038] Fig. 3 is a diagram showing an example of a rolling lane T of a vibratory roller in an embankment S. As shown in Fig. 3, a plurality of rolling lanes T extending along a traveling direction D1 are provided in the embankment S. The plurality of rolling lanes T are lined up along a cross direction D3, which is a direction intersecting the traveling direction D1.

[0039] The vibratory roller compacts the embankment S by moving in the direction of travel D1 along the rolling lane T, and after compacting the rolling lane T, moves to the adjacent rolling lane T. At this time, a step may occur between two adjacent rolling lanes T along the cross direction D3 along with the tracks of the vibratory roller. The height of this step is, for example, 5 cm or more and 10 cm or less.

[0040] The resistivity measuring device 1 measures the resistivity of the embankment S while traveling in the direction of travel D1 along the rolling lane T where the vibrating roller has performed compaction. At this time, there is a concern that the electrode 4 may get caught on the step and be damaged. In particular, if the embankment S is CSG, the hardness of the embankment surface S1 raises the concern that the electrode 4 may be damaged by colliding with the hard step. Furthermore, when the resistivity measuring device 1 moves from one rolling lane T to another rolling lane T adjacent to the current rolling lane T, it makes a U-turn, for example. If the turning radius during this U-turn is large, it may not be possible to move efficiently to the adjacent rolling lane T. Therefore, when measuring resistivity while moving along multiple rolling lanes T, there is a concern that the measurement may not be performed efficiently.

[0041] The traveling body 3 and electrode accommodating unit 5 of the resistivity measuring device 1 according to this embodiment can prevent the above-mentioned problems from occurring. Below, detailed examples of the traveling body 3 and the electrode accommodating unit 5 will be described with reference to FIGS. 4 and 5. As shown in FIGS. 4 and 5, the electrode accommodating unit 5 has a bottom 5b that contacts the embankment S and an inclined portion 5c that extends obliquely upward from the end of the bottom 5b on the traveling direction D1 side. The electrode 4 is placed on the upper surface of the bottom 5b inside the electrode accommodating unit 5. When the traveling body 3 is not on the step Z, the bottom 5b extends horizontally, and the inclined portion 5c extends obliquely upward from the front end of the bottom 5b.

[0042] The end (front end) of the inclined portion 5c on the traveling direction D1 side is located on the opposite side (rear side) of the traveling direction D1 from the ends of the plurality of rolling elements 3b on the traveling direction D1 side. The plurality of rolling elements 3b include two front wheels 3c located on the traveling direction D1 side of the traveling element 3 and two rear wheels 3d located on the opposite side of the traveling direction D1 of the traveling element 3 from the two front wheels 3c. For example, each of the front wheels 3c and the rear wheels 3d includes a tire 3g and a wheel 3h. For example, the resistivity measuring device 1 has a front wheel steering mechanism that interlocks the two front wheels 3c.

[0043] The front end of the inclined portion 5c is located rearward of the center of the front wheel 3c. For example, the distance x from the center of the front wheel 3c to the front end of the inclined portion 5c is equal to or less than a certain value. In this case, the possibility that the electrode accommodating portion 5 will come into contact with the step Z can be further reduced. Below, we will explain what value the distance x should be so that the traveling object 3 and the electrode accommodating portion 5 can clear the step Z.

[0044] First, when the front wheel 3c rides over the step Z, the electrode accommodating section 5 is separated from the raised surface S1. For example, if the distance from the center of the front wheel 3c to the center of the rear wheel 3d is L and the height of the step Z is h, the inclination θ of the traveling body 3 with respect to the horizontal plane is expressed by the following equation (1).

number

[0045] In order for the running body 3 to get over the step Z, it is necessary for the front end of the electrode accommodating part 5 to clear the end B of the step Z on the side of the electrode accommodating part 5. If the intersection of the perpendicular line extending from the end B to the diameter of the front wheel 3c and this diameter is C, and the end of this diameter on the step Z side is A, and if ∠ABC=θ and BC=x, then AC=x×tanθ.

[0046] When the electrode accommodating section 5 is away from the mounding surface S1, the distance from the lower end of the running body 3 to the electrode accommodating section 5 is d, the height (vertical projection height) of the electrode accommodating section 5 is g, and the horizontal length (horizontal projection distance) of the inclined section 5c is l, in order for the electrode accommodating section 5 to exceed the end B of the step Z, the value of AC+d must be less than the value of g. Therefore, when g≧AC+d=x×tanθ+d is calculated for x, x satisfies the following formula (2).

number

[0047] According to formula (2), if the distance x from the center of the front wheel 3c to the front end of the inclined portion 5c is equal to or less than (gd) / tan θ, the possibility of the electrode accommodating portion 5 coming into contact with the step Z can be reduced. Furthermore, if the radius of the rear wheel 3d and the radius of the front wheel 3c are R, it is desirable that R≧2h be satisfied, that is, that the radius R is at least twice the height h of the step Z. In this case, the running object 3 can more reliably overcome the step Z, thereby improving its traversal capability. As an example, since the maximum expected height h of the step Z is about 10 cm, it is desirable that the radius R be at least 20 cm.

[0048] 1 and 5, the running body 3 includes a handle 3f that can be gripped when lifting the running body 3. For example, the running body 3 has a plurality of handles 3f. The handles 3f are arranged in the cross direction D3. This makes it easy to carry the running body 3.

[0049] Next, a detailed example of the electrode 4 and the electrode housing unit 5 will be described with reference to FIG. 6. FIG. 6 is a perspective view showing the electrode 4 and the electrode housing unit 5 when removed from the traveling body 3. As shown in FIG. 6, the electrode 4 has an electrode plate 4k. When the electrode housing unit 5 is attached to the traveling body 3, the electrode plate 4k extends in the traveling direction D1 and the intersecting direction D3 and has a thickness in the direction D2. For example, the electrode plate 4k has a polygonal shape. As an example, the electrode plate 4k has a rectangular shape. However, the shape of the electrode plate 4k may be circular and is not particularly limited.

[0050] Fig. 7(a) is a perspective view of the electrode accommodating section 5 as seen from above. Fig. 7(b) is a rear view of the electrode accommodating section 5 as seen from behind. Fig. 7(c) is a side view of the electrode accommodating section 5 as seen from the side. As shown in Figs. 6, 7(a), 7(b), and 7(c), the electrode accommodating section 5 has a bottom 5b, an inclined section 5c, and a pair of lateral inclined sections 5d.

[0051] For example, the bottom portion 5b has a pair of first extending portions 5b1 extending in the traveling direction D1 and a second extending portion 5b2 extending in the intersecting direction D3 at the front end of the pair of first extending portions 5b1. The bottom portion 5b is the portion that comes into contact with the pile surface S1 when the electrode accommodating portion 5 is attached to the traveling body 3. The bottom portion 5b is detachable from the inclined portion 5c and the side inclined portion 5d. Therefore, the bottom portion 5b is replaceable.

[0052] The inclined portion 5c extends obliquely upward from the front end of the bottom portion 5b. The inclined portion 5c has, for example, an attachment portion 5c1 to which the bottom portion 5b is attached and an extending portion 5c2 extending obliquely upward and forward from the attachment portion 5c1. The attachment portion 5c1 extends in the intersecting direction D3. A second extending portion 5b2 of the bottom portion 5b is attached to the attachment portion 5c1. The inclined portion 5c (extending portion 5c2) extends in the intersecting direction D3 and is inclined with respect to both the traveling direction D1 and the direction D2.

[0053] The lateral inclined portions 5d extend rearward from both ends of the inclined portion 5c in the intersecting direction D3. The lateral inclined portions 5d extend diagonally upward as they move away from the bottom portion 5b. The lateral inclined portions 5d have, for example, an attachment portion 5d1 to which the bottom portion 5b is attached, and an extending portion 5d2 that extends diagonally upward from the attachment portion 5d1 to both ends of the electrode accommodating portion 5 in the intersecting direction D3. The attachment portion 5d1 extends in the traveling direction D1. A first extending portion 5b1 of the bottom portion 5b is attached to the attachment portion 5d1. The lateral inclined portions 5d (extending portions 5d2) extend in the traveling direction D1 and are inclined with respect to both the direction D2 and the intersecting direction D3.

[0054] For example, the height (length in direction D2) of inclined portion 5c is constant. In contrast, the height of side inclined portion 5d decreases with increasing distance from inclined portion 5c (toward the rear). For example, upper end 5d3 of side inclined portion 5d is curved so that side inclined portion 5d bulges out.

[0055] For example, the electrode plate 4k is detachably attached to the inclined portion 5c and the side inclined portion 5d. As an example, the electrode plate 4k is fixed to the side inclined portion 5d with screws while being placed on the attachment portion 5c1 of the inclined portion 5c and the attachment portion 5d1 of the side inclined portion 5d.

[0056] For example, the electrode plate 4k and the electrode accommodating portion 5 have holes H through which the above-mentioned spring mechanisms 7 are passed. As an example, the holes H are formed at one end and the other end of each mounting portion 5d1 in the direction of travel D1, and at each of the four corners of the electrode plate 4k. An example of the detailed configuration of the electrode 4 and the electrode accommodating portion 5 has been described above. However, the configuration of the electrode 4 and the electrode accommodating portion 5 is not limited to the above example and can be modified as appropriate.

[0057] Next, an example of the steps of the embankment evaluation method according to this embodiment will be described. An example of a method for evaluating an embankment S using the resistivity measuring device 1 described above will be described below. First, as shown in Fig. 1, a traveling body 3 having a pair of current electrodes 4c is connected to a traction unit 2 by a linear body 6b, and the traveling body 3 having a pair of potential electrodes 4b is connected to the traveling body 3 having a pair of current electrodes 4c by a linear body 6c (the step of connecting the traveling body).

[0058] Next, the resistivity measuring device 1 is moved on the embankment S by moving the towing unit 2 in the traveling direction D1 (step of moving the resistivity measuring device). Then, the resistivity measuring device 1 measures the resistivity of the embankment S (step of measuring the resistivity). At this time, the resistivity of the embankment S is measured while the traveling body 3 supporting the electrode housing unit 5 that houses each of the potential electrode 4b and the current electrode 4c is moved in the traveling direction D1 on the embankment S. For example, the measured resistivity may be collected by the data collecting unit 8 and displayed on the display unit 9.

[0059] Then, the data collecting unit 8 calculates the density of the embankment S from the measured resistivity (a step of calculating density). The calculated density may be displayed as a map on the display unit 9. In this case, as one example, areas of the embankment S with high density may be displayed on the display unit 9 in a first color, and areas of low density may be displayed on the display unit 9 in a second color different from the first color. When the density of the embankment S is displayed for each area in this way, the quality of the embankment S can be visually grasped.

[0060] Next, the data collection unit 8 judges the quality of the embankment S (step of determining the quality of the embankment). For example, the data collection unit 8 judges that the quality of the embankment S is good if the density is equal to or greater than a certain value, and judges that the quality of the embankment S is not good if the density is not equal to or greater than the certain value. For example, if the data collection unit 8 judges that the quality of the embankment S is good for all areas of the embankment S as a result of its quality judgment, the series of steps of the embankment evaluation method is completed. On the other hand, if it is judged that there is an area where the quality of the embankment S is not good, at least one of re-measuring the resistivity of the embankment S and compacting the embankment S may be performed.

[0061] In the re-measurement, for example, the resistivity measuring device 1 is run over the embankment S again to measure the resistivity, and the above-mentioned steps are performed again. In the compaction, the embankment surface S1 of the embankment S is compacted again by a compaction machine. After going through the above steps, the series of steps in the embankment evaluation method is completed.

[0062] Next, the effects obtained from the resistivity measuring device 1 and embankment evaluation method according to this embodiment will be described. In the resistivity measuring device 1 and embankment evaluation method according to this embodiment, the resistivity of the embankment S is measured with a pair of potential electrodes 4b and a pair of current electrodes 4c facing the embankment S. The potential electrodes 4b and the current electrodes 4c are each housed in an electrode housing portion 5. Therefore, the potential electrodes 4b and the current electrodes 4c can be protected by the electrode housing portion 5.

[0063] 4 and 5, the resistivity measuring device 1 has a traveling body 3 equipped with a plurality of rolling elements 3b, and the traveling body 3 moves along the traveling direction D1 together with the electrode accommodating portion 5 as the plurality of rolling elements 3b roll on the embankment S. The electrode accommodating portion 5 has an inclined portion 5c that extends obliquely upward from the end of the bottom 5b of the electrode accommodating portion 5 on the traveling direction D1 side. The electrode accommodating portion 5 has the inclined portion 5c on the traveling direction D1 side, which makes it easier for the electrode accommodating portion 5 to overcome unevenness.

[0064] Furthermore, the end of the inclined portion 5c of the electrode accommodating portion 5 on the traveling direction D1 side is located on the opposite side of the traveling direction D1 from the end of the rolling element 3b on the traveling direction D1 side. Therefore, when the traveling element 3 travels, the rolling element 3b comes into contact with the step Z before the inclined portion 5c of the electrode accommodating portion 5. This reduces the possibility that the electrode accommodating portion 5 will come into contact with the step Z, thereby preventing the electrode 4 from being damaged.

[0065] In this embodiment, the multiple rolling elements 3b include two front wheels 3c located on the traveling direction D1 side of the traveling element 3, and two rear wheels 3d located on the opposite side (rear side) of the traveling direction D1 of the traveling element 3 as viewed from the two front wheels 3c. The resistivity measuring device 1 is equipped with a front wheel steering mechanism that interlocks the two front wheels 3c. In this case, by providing a front wheel steering mechanism that interlocks the two front wheels 3c, the turning radius of the traveling element 3 when turning can be reduced. Therefore, movement to the next rolling lane T can be easily performed by turning.

[0066] In this embodiment, as shown in FIG. 2(a), the resistivity measuring device 1 has a spring mechanism 7 provided corresponding to each of the multiple electrode housing units 5, which urges each electrode housing unit 5 toward the embankment S. In this case, the electrode housing units 5, which hold the pair of potential electrodes 4b and the pair of current electrodes 4c facing the embankment S, are urged toward the embankment S by the spring mechanism 7. Therefore, the pair of potential electrodes 4b and the pair of current electrodes 4c are urged by the spring mechanism 7 so as to be pressed against the embankment S, so that each potential electrode 4b and each current electrode 4c can be made to follow the embankment S even if there is unevenness. This makes it possible to easily and accurately measure the resistivity of the embankment S.

[0067] 7(a), 7(b), and 7(c), the inclined portion 5c extends in a cross direction D3 that crosses the traveling direction D1. The electrode accommodating portion 5 has a pair of side inclined portions 5d that extend in the opposite direction (rearward) from both ends of the inclined portion 5c in the cross direction D3. In this case, the provision of the pair of side inclined portions 5d more reliably protects the electrode 4 even when the traveling object 3 travels obliquely with respect to the traveling direction D1.

[0068] In this embodiment, the potential electrode 4b and the current electrode 4c are each placed on the bottom 5b of the electrode housing 5, and the bottom 5b is detachable from the inclined portion 5c. In this case, the bottom 5b and the electrode 4 can be detached from the inclined portion 5c in the electrode housing 5. Therefore, even if the bottom 5b or the electrode 4 that comes into contact with the embankment S breaks down, it is possible to replace only the bottom 5b or only the electrode 4. This reduces the need to replace the entire electrode housing 5, thereby suppressing increases in costs associated with the electrode housing 5.

[0069] Next, a resistivity measuring device according to a modified example will be described. A portion of the configuration of the resistivity measuring device according to the modified example described below is the same as a portion of the configuration of the resistivity measuring device 1 described above. Therefore, in the following description, the same reference numerals will be used to designate parts that overlap with the description of the resistivity measuring device 1, and the description will be omitted as appropriate.

[0070] Fig. 8 is a perspective view of a resistivity measurement device 1A according to the first modification, viewed from below. As shown in Fig. 8, the resistivity measurement device 1A differs from the resistivity measurement device 1 described above in that it includes a circular electrode 4A and a circular electrode accommodating portion 5A, and in that it includes a four-wheel steering mechanism instead of a front-wheel steering mechanism.

[0071] The resistivity measuring device 1A has a running body 3A that is different from the running body 3. The running body 3A has a first support portion 3j that supports a plurality of electrode housing portions 5A, and a plurality of second support portions 3k that support a plurality of rolling elements 3b on the downward surface of the first support portion 3j. The second support portion 3k that supports the rolling elements 3b is supported so as to be rotatable in the horizontal direction relative to the first support portion 3j. The second support portion 3k rotates together with the rolling elements 3b.

[0072] The running body 3A has a rod-shaped member 3p that connects the front wheel 3c and the rear wheel 3d to each other. The running body 3A has two rod-shaped members 3p. One of the two rod-shaped members 3p connects the front wheel 3c located on one side of the intersecting direction D3 to the rear wheel 3d located on one side of the intersecting direction D3 to each other. The other of the two rod-shaped members 3p connects the front wheel 3c located on the other side of the intersecting direction D3 to the rear wheel 3d located on the other side of the intersecting direction D3 to each other.

[0073] For example, the second support portion 3k that supports the front wheel 3c extends from the front wheel 3c toward the center in the intersecting direction D3 of the running body 3A. The second support portion 3k that supports the rear wheel 3d extends from the rear wheel 3d to both ends in the intersecting direction D3 of the running body 3A. The rod-shaped member 3p extends from the part of the second support portion 3k that supports the front wheel 3c that extends toward the center in the intersecting direction D3 to the part of the second support portion 3k that supports the rear wheel 3d that extends to both ends in the intersecting direction D3. This rod-shaped member 3p allows the rear wheel 3d to rotate in conjunction with the rotation of the front wheel 3c of the running body 3A.

[0074] As described above, the provision of the rod-shaped members 3p on the traveling body 3A allows the location where the front wheels 3c and the rear wheels 3d travel to coincide with each other. This further reduces the turning radius of the traveling body 3A, allowing it to move efficiently to the adjacent rolling lane T (see FIG. 3) and measure resistivity efficiently. In this way, the resistivity measuring device 1A is provided with a four-wheel steering mechanism that links the front wheels 3c and rear wheels 3d, thereby further reducing the turning radius of the traveling body 3A when turning, making it even easier to move to the next rolling lane T.

[0075] Next, a resistivity measuring device 1B according to a second modification will be described with reference to FIG. 9. In FIG. 9, to avoid complexity, components that overlap with those of the resistivity measuring device 1 described above are illustrated in a simplified form. The resistivity measuring device 1B has a running body 3B that is different from the running body 3. The running body 3B has a plurality of rolling bodies 3q and a support portion 3r that supports a plurality of electrode housing portions 5. As an example, the support portion 3r is plate-shaped and extends in the traveling direction D1 and the intersecting direction D3.

[0076] For example, the resistivity measuring device 1B has a control unit 10 that controls the measurement of resistivity by the electrodes 4, and a cover 11 that covers the control unit 10. The control unit 10 and the cover 11 are provided, for example, for each running body 3B. The control unit 10 is disposed on a support part 3r of the running body 3B, and the cover 11 covers the control unit 10 disposed on the support part 3r. Therefore, the control unit 10 can be protected by the cover 11.

[0077] The rolling elements 3q include two front wheels 3c aligned along the transverse direction D3, two rear wheels 3d aligned along the transverse direction D3, and an auxiliary wheel 3s positioned in front of the front wheels 3c. For example, the running element 3B has two auxiliary wheels 3s. As an example, the running element 3B has a rod-shaped member 3t connecting the auxiliary wheels 3s to the front wheels 3c. In this case, the running element 3B has two rod-shaped members 3t aligned along the transverse direction D3, and the auxiliary wheels 3s are connected to the front wheels 3c via the two rod-shaped members 3t.

[0078] As described above, in the resistivity measuring device 1B, each of the multiple traveling bodies 3B has the auxiliary wheels 3s located forward of the front wheels 3c. By providing the auxiliary wheels 3s in front of the front wheels 3c, the auxiliary wheels 3s hit the step Z first, making it even easier for the traveling body 3B to overcome the step Z. Therefore, collision of the electrode accommodating portion 5 with the step Z can be more reliably avoided.

[0079] Next, an embankment evaluation system 20 according to a third modified example will be described with reference to Fig. 10. The embankment evaluation system 20 differs from the resistivity measurement device 1 described above in that it includes a moisture meter 21. The embankment evaluation system 20 includes the resistivity measurement device 1 described above and the moisture meter 21 connected to the resistivity measurement device 1. The moisture meter 21 is, for example, a portable device.

[0080] The moisture meter 21 is connected to the resistivity measurement device 1 (traveling body 3) via the linear body 6d. However, the moisture meter 21 may be connected to the towing unit 2 via the linear body 6d. In this case, the moisture meter 21 is located between the towing unit 2 and the resistivity measurement device 1, i.e., in front of the resistivity measurement device 1.

[0081] The moisture meter 21 measures the volumetric moisture content of the embankment S while facing the embankment S. The moisture meter 21 has, for example, a moisture measuring unit 22, a running body 23, and a holding unit 24 that is attached to the underside of the running body 23 and holds the moisture measuring unit 22. The running body 23 has a plurality of wheels 23b and a base 23c provided on the upper part of the plurality of wheels 23b. The holding unit 24 is attached to the underside of the base 23c and holds the moisture measuring unit 22 therein. The holding unit 24 is made of, for example, metal. The holding unit 24 has a recess that houses the moisture measuring unit 22, and the underside of the recess contacts the embankment surface S1. The moisture measuring unit 22 measures the volumetric moisture content of the embankment S while contacting the embankment surface S1 via the underside.

[0082] For example, the moisture meter 21 is a scattering-type RI moisture meter. In this case, the moisture meter 21 has a radiation source that is a neutron radiation source, a detection tube that is a thermal neutron radiation detection unit, and a housing that houses the radiation source and the detection tube. The radiation source emits fast neutrons to the embankment S. The fast neutrons emitted to the embankment S are scattered. Some of the scattered fast neutrons collide with hydrogen atoms in the embankment S. The fast neutrons that collide with the hydrogen atoms lose their speed and become thermal neutrons. The moisture meter 21 measures the volumetric moisture content of the embankment S by detecting the thermal neutrons generated in the embankment S with the detection tube. The above describes an example in which the moisture meter 21 is a scattering-type RI moisture meter. However, the moisture meter 21 may also be a near-infrared moisture meter. In this case, the cost of the moisture meter 21 can be reduced. In this way, the type of moisture meter 21 can be changed as appropriate.

[0083] The moisture meter 21 moves over the embankment surface S1 to measure the volumetric moisture content simultaneously with the movement of the resistivity measuring device 1. For example, the data collection unit 8 calculates the density of the embankment S from the resistivity measured by the resistivity measuring device 1 and the volumetric moisture content measured by the moisture meter 21. For example, the embankment evaluation system 20 may calculate at least one of the density of the embankment S and the moisture content of the embankment S as an evaluation item of the embankment S.

[0084] The embankment evaluation system 20 evaluates the embankment S by measuring the density and moisture content of the embankment S, and confirms the effectiveness of compaction by the compaction machine. In this way, the embankment evaluation system 20 evaluates the embankment S taking into account the volumetric moisture content measured by the moisture meter 21, making it possible to evaluate the compacted embankment S with higher accuracy.

[0085] The above describes embodiments and various modifications of the resistivity measurement device and embankment evaluation method according to the present disclosure. However, the resistivity measurement device and embankment evaluation method according to the present disclosure are not limited to the above-described embodiments or modifications, and may be further modified within the scope of the gist described in the claims. In other words, the configuration, shape, size, material, number, and arrangement of each part of the resistivity measurement device and embankment evaluation system according to the present disclosure, 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.

[0086] For example, in the above-described embodiment, an example was described in which the towing unit 2 was a drivable vehicle. However, the towing unit may not be driven but may be self-propelled. On the other hand, the towing unit may be towed manually. In this way, the type of towing unit can be changed as appropriate.

[0087] In the above-described embodiment, the resistivity measuring device 1 is described as including two traveling bodies 3, each of which is provided with two electrodes 4 (electrode housing portions 5). However, the number of traveling bodies included in the resistivity measuring device and the number of electrodes (electrode housing portions) included in the traveling bodies can be changed as appropriate.

[0088] In the above-described embodiment, the electrode accommodating section 5 has been described as having a bottom 5b, inclined sections 5c, and side inclined sections 5d. However, the electrode accommodating section may not have the side inclined sections 5d. Furthermore, the electrode accommodating section may have inclined sections provided on the front, back, left, right, and right sides (or the entire periphery) of the bottom. In this way, the shape of the electrode accommodating section can also be changed as appropriate. [Explanation of symbols]

[0089] 1,1A,1B…Specific resistance measuring device, 2…Traction part, 2b…Wheel, 2c…Connecting part, 3,3A,3B…Runner, 3b…Rotating body, 3c…Front wheel, 3d…Rear wheel, 3f…Handle, 3g…Tire, 3h…Wheel, 3j…First support part, 3k…Second support part, 3p…Rod-shaped part, 3q…Rotating body, 3r…Support wheel, 3s…Auxiliary wheel, 3t…Rod-shaped part, 4,4A…Electrode, 4b…Potential electrode, 4c…Current electrode, 4d…Electrifying element, 4f…Conductor, 4h…AC power supply, 4j…Potential meter, 4k…Electrode plate, 5,5A…Electrode housing part, 5b…Bottom, 5b1…First extension part, 5b2…Second extension part, 5c… …sloping part, 5c1…receiving part, 5c2…extending part, 5d…sloping part, 5d1…receiving part, 5d2…extending part, 5d3…upper end, 6b, 6c, 6d…linear body, 7…bane mechanism, 8…data collection part, 9…indicator part, 10…control part, 11…cover, 20…soil evaluation system, 21…moisture meter, 22 …Moisture measuring section, 23…running body, 23b…wheel, 23c…platform, 24…holding section, B…end, D1…direction, D2…direction, D3…intersecting direction, E…certain range, G…site, H…hole, P…point, R…radius, S…soil filling, S1…soil filling elevation, T…pressure line, x…distance, Z…step difference, θ…tilt.

Claims

1. A resistivity measuring device having a pair of potential electrodes and a pair of current electrodes that face the embankment and measure the resistivity of the embankment, an electrode housing portion that houses the potential electrode and the current electrode; a traveling body that supports the electrode housing portion and has a plurality of rolling bodies that roll on the embankment, and that travels on the embankment along the traveling direction together with the electrode housing portion; Equipped with The electrode accommodating portion has a bottom portion that contacts the embankment and an inclined portion that extends obliquely upward from an end portion of the bottom portion on the traveling direction side, an end portion of the inclined portion on the traveling direction side is located on the opposite side of the traveling direction from ends of the plurality of rolling elements on the traveling direction side; Specific resistance measuring device.

2. the plurality of rolling elements include two front wheels positioned on the traveling direction side of the traveling body, and two rear wheels positioned on the opposite side of the traveling direction of the traveling body as viewed from the two front wheels, a front wheel steering mechanism that couples the two front wheels; The resistivity measuring device according to claim 1 .

3. A spring mechanism is provided corresponding to each of the plurality of electrode accommodating sections, and biases each of the electrode accommodating sections against the embankment. The resistivity measuring device according to claim 1 .

4. the inclined portion extends in a cross direction that is a direction that crosses the traveling direction, The electrode accommodating portion has a pair of side inclined portions extending in a direction opposite to the traveling direction from both ends of the inclined portion in the intersecting direction. The resistivity measuring device according to claim 1 .

5. the potential electrode and the current electrode are each placed on the bottom of the electrode housing; The bottom portion is detachable from the inclined portion. The resistivity measuring device according to claim 1 .

6. A method for evaluating the quality of an embankment using the resistivity measuring device according to any one of claims 1 to 5, measuring the resistivity of the embankment while causing the traveling body, which supports the electrode housing parts that house the potential electrode and the current electrode, to travel in the direction of travel on the embankment; calculating the density of the embankment from the resistivity; determining the quality of the embankment from the density; Equipped with Embankment evaluation methods.

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