Resistivity measuring device

Abstract

The present invention provides a resistivity measuring device that reduces wear of the insulating material interposed between the electrode and the ground. [Solution] The resistivity measuring device 1 is a device for measuring the resistivity of an embankment G, comprising a cylindrical part 11 which is an insulating member that contacts the compacted surface S of the embankment G to be measured, and an electrode 25 which is connected to the compacted surface S via the cylindrical part 11. The cylindrical part 11 is cylindrical in shape and rolls on the compacted surface S, and the electrode 25 is arranged in the hollow part 11q of the cylindrical part 11, sliding in contact with the inner circumferential surface 11b of the cylindrical part 11, and positioned opposite the compacted surface S with the cylindrical wall 11p of the cylindrical part 11 in between.

Description

Technical Field

[0001] The present invention relates to a specific resistance measuring device.

Background Art

[0002] Conventionally, the specific resistance value of the ground has been used as one of the measured values for evaluating the compaction quality of compacted fill or the like. As a conventional specific resistance measuring device for comprehensively measuring the specific resistance value of the ground in a target area, the one described in Patent Document 1 below is known. In this device, the specific resistance of the ground is measured with a pair of potential electrodes and a pair of current electrodes held by a holding body facing the ground through an insulator member. By sliding the insulator member contacting the lower surface of each electrode on the ground, the state where each electrode contacts the ground through the insulator member is maintained.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the above device has a problem that wear of the insulator member sliding on the ground easily occurs. And when the wear of the insulator member is large, it becomes necessary to frequently replace or maintain it. In view of this problem, an object of the present invention is to provide a specific resistance measuring device that reduces the wear of the insulator member interposed between the electrode and the ground.

Means for Solving the Problems

[0005] The gist of the present invention resides in the following [1] to [6].

[0006] [1] A resistivity measuring device for measuring the resistivity of the ground while moving on the ground, comprising a probe portion having an insulating member that contacts the ground of the ground to be measured and an electrode connected to the ground via the insulating member, wherein the insulating member has a cylindrical shape that rolls on the ground, and the electrode is arranged in the hollow part of the cylinder of the insulating member, slides against the inner circumferential surface of the cylinder of the insulating member, and is positioned facing the ground with the cylindrical wall of the insulating member in between.

[0007] [2] The resistivity measuring device according to [1], wherein the probe portion comprises a shaft extending along the cylindrical axis of the insulating member and fixed to the insulating member, and an electrode portion rotatably suspended from the shaft at one end and having the electrode at the other end, the electrode portion adopts a position with the electrode facing vertically downward due to its own weight.

[0008] [3] The resistivity measuring device according to [2], further comprising a trolley that moves on the ground and a connecting part that connects the trolley and the probe part, wherein the connecting part rotatably supports the shaft.

[0009] [4] The resistivity measuring device according to [3], further comprising conductive wires drawn out from the electrodes for electrical connection between the electrodes and other devices on the trolley.

[0010] [5] The resistivity measuring device according to any one of [1] to [4], comprising a pair of current electrodes for applying an alternating current voltage to the ground and a pair of potential electrodes for measuring a potential difference generated in the ground in response to the alternating current voltage, wherein at least one of the pair of current electrodes and the pair of potential electrodes is included as the electrode in the probe portion.

[0011] [6] The resistivity measuring device according to any one of [1] to [5], wherein the outer surface of the insulating member is provided with a high-friction region for increasing friction between the outer surface and the ground. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a resistivity measuring device that reduces wear of an insulating member interposed between an electrode and the ground. [Brief explanation of the drawing]

[0013] [Figure 1] (a) is a perspective view of the resistivity measuring device of the embodiment, viewed from below, and (b) is a side view thereof. [Figure 2] (a) is a front view of the probe section, and (b) is a partially cutaway front view showing the cylindrical and cover sections of the probe section. [Figure 3] (a) is a cross-sectional view of IIIa-IIIa in Figure 2(b), (b) is a cross-sectional view of IIIb-IIIb, and (c) is a perspective view showing the relationship between the electrode and the shaft. [Figure 4] This is a schematic circuit diagram showing the electrical circuit configured during the use of the resistivity measuring device 1. [Figure 5] (a) and (b) are partially broken front views of the probe portion relating to each modified example. [Figure 6] (a) to (d) are plan views of the trolley for each modified example. [Modes for carrying out the invention]

[0014] Hereinafter, an embodiment of the resistivity measuring device according to the present invention will be described in detail with reference to the drawings. Figure 1(a) is a perspective view of the resistivity measuring device 1 of this embodiment, viewed from below, and Figure 1(b) is a side view thereof. The resistivity measuring device 1 is used, for example, at a dam construction site. At the site, for example, soil is transported by dump trucks, the transported soil is spread and leveled by bulldozers to form an embankment G, and this embankment G is compacted by vibratory rollers. The embankment G is, for example, CSG (Cemented Sand and Gravel). Alternatively, the embankment G may be RCD (Roller Compacted Dam Concrete), and the type of embankment G is not particularly limited.

[0015] The resistivity measuring device 1 is a device for measuring the resistivity of the ground. The resistivity measuring device 1 is used to measure the resistivity of the embankment G (ground) as one of the measurement values ​​for evaluating the compaction quality of the embankment G. The resistivity measuring device 1 measures the resistivity of the embankment G while traveling on the compaction surface S (ground) of the embankment G over the entire area to be measured. Here, the compaction surface S is approximately a horizontal plane, but it may be inclined with a slope (10 degrees or less) that allows the compaction vehicle to travel on it.

[0016] The resistivity measuring device 1 comprises a traveling carriage 3 that can travel on a compacted surface S, and a probe portion 5 that is attached to the traveling carriage 3 and contacts the compacted surface S.

[0017] The trolley 3 has, for example, a flat body 7 and wheels 9 provided on the body 7, and travels on the compaction surface S in the direction of arrow J. In the example shown in the figure, the trolley 3 is a four-wheeled vehicle with wheels 9 provided at each of the four corners of a rectangular body 7. The trolley 3 does not have its own power source and travels on the compaction surface S by being towed, for example, by a towing vehicle (not shown) driven by a worker. The towing vehicle may move automatically on the compaction surface S. Alternatively, the trolley 3 may have its own power source and be able to move on the compaction surface S under its own power. In this case, the trolley 3 may be a vehicle driven by a worker and may travel on the compaction surface S by automatic operation. The probe unit 5 is attached to the underside of the body 7 of the trolley 3 and is always in contact with the compaction surface S while the trolley 3 is traveling, sensing the compaction surface S.

[0018] On the upper surface of the vehicle body 7 of the traveling carriage 3, a control unit 10 composed of electronic components is mounted. The control unit 10 and the probe unit 5 are connected via a conductive wire 19 (see FIG. 2) for the exchange of electrical signals. The control unit 10 calculates the specific resistance value of the ground based on the electrical signal obtained from the probe unit 5. Alternatively, the control unit 10 may accumulate and store the electronic information obtained from the probe unit 5. Alternatively, the control unit 10 may relay the electronic information obtained from the probe unit 5 and transmit it to other computers or the like by wire or wirelessly. The above-mentioned other computers or the like may be mounted on a towing vehicle that towes the traveling carriage 3, or may be arranged at the site within a wireless communication distance away from the towing vehicle and the traveling carriage 3.

[0019] Details of the probe unit 5 will be described. FIG. 2(a) is a front view of the probe unit 5, and FIG. 2(b) is a partially broken front view showing the cylindrical portion 11 and the cover portion 21 broken. FIG. 3(a) is a sectional view taken along the line IIIa-IIIa of the probe unit 5, and FIG. 3(b) is a sectional view taken along the line IIIb-IIIb thereof. The probe unit 5 is rotatable about a rotation axis H with respect to the traveling carriage 3. The rotation axis H is parallel to the rotation axis of the wheels 9 of the traveling carriage 3, that is, it extends in the vehicle width direction of the traveling carriage 3. The probe unit 5 is in contact with the rolling pressure surface S and rolls on the rolling pressure surface S as the traveling carriage 3 travels.

[0020] The probe unit 5 includes a cylindrical portion 11, a shaft 13, a spoke portion 15, an electrode portion 17, a conductive wire 19, and a cover portion 21. The cylindrical portion 11 has a cylindrical shape with the rotation axis H as the cylindrical axis, and the outer peripheral surface 11a of the cylindrical portion 11 is in contact with the rolling pressure surface S. The cylindrical portion 11 is made of an electrically insulating material such as resin. The material of the cylindrical portion 11 is preferably one with high wear resistance. For example, high-density polyethylene resin, hard polyurethane resin, ABS (Acrylonitrile Butadiene Styrene), etc. can be adopted. The wall thickness of the cylindrical wall 11p of the cylindrical portion 11 is, for example, about 5 mm. The diameter of the cylindrical portion 11 is, for example, about 200 mm.

[0021] The shaft 13 extends on the rotation axis H and protrudes from both ends of the cylindrical portion 11. The shaft 13 is made of, for example, a resin material. The spoke portion 15 is provided in the hollow portion 11q of the cylindrical portion 11 at the axial center position of the cylindrical portion 11 and connects the cylindrical portion 11 and the shaft 13. The spoke portion 15 is composed of, for example, a plurality of rod-shaped portions that extend radially from the shaft 13 to the inner peripheral surface 11b of the cylindrical portion 11. The outermost peripheral end of the spoke portion 15 is fixed to the inner peripheral surface 11b of the cylindrical portion 11. The spoke portion 15 is made of, for example, a resin material.

[0022] The electrode portion 17 is disposed in the hollow portion 11q of the cylindrical portion 11 and supported by the shaft 13. The electrode portion 17 has an electrode holding arm 23 and an electrode 25. The electrode holding arm 23 extends linearly in the radial direction from the shaft 13. The electrode holding arm 23 is made of, for example, a resin material. The electrode 25 is a metal electrode attached to the tip of the electrode holding arm 23. The electrode 25 has a cylindrical surface along the shape of the inner peripheral surface 11b of the cylindrical portion 11, and is in surface contact with the inner peripheral surface 11b of the cylindrical portion 11 along the cylindrical surface.

[0023] The probe portion 5 includes four such electrode portions 17. The electrode portions 17 are respectively present on both sides with the spoke portion 15 sandwiched therebetween, and are arranged in a predetermined positional relationship. The four electrodes 25 are composed of two current electrodes 25A and 25B and two potential electrodes 25C and 25D. In the probe portion 5 of the present embodiment, it is assumed that the electrodes 25A, 25B, 25C, and 25D are arranged in the extending direction of the shaft 13 in this order.

[0024] The conductive wires 19 are respectively drawn out from each electrode 25. Then, the conductive wires 19 are routed to the side of the traveling carriage 3 through the openings at both axial ends of the cylindrical portion 11 and connected to the control unit 10. Each electrode 25 is electrically connected to the control unit 10 through each conductive wire 19, and exchanges electrical signals with the control unit 10. Note that the conductive wires 19 may be installed so as to crawl on a connecting arm 27 described later.

[0025] The cover portion 21 is attached, for example, to both ends of the shaft 13 and closes the openings at both axial ends of the cylindrical portion 11. The cover portion 21 is made of, for example, a resin material. The presence of this cover portion 21 prevents soil and sand on the compacted surface S from entering the hollow portion 11q of the cylindrical portion 11, thereby suppressing adverse effects of soil and sand on the electrodes 25, etc.

[0026] The resistivity measuring device 1 is equipped with a connecting arm 27 (connecting part) for connecting the probe part 5 described above to the trolley 3. The probe part 5 is fixed to the underside of the vehicle body 7 via two connecting arms 27 that support the shaft 13 from both sides. The tip of each connecting arm 27 is attached to both ends of the shaft 13, and the base end of each connecting arm 27 is fixed to the underside of the vehicle body 7. The connecting arms 27 are made of, for example, a resin material.

[0027] The mechanism of the probe unit 5 will now be described. The connecting arm 27 supports the shaft 13 so that it can rotate around the rotation axis H. The shaft 13 is fixed to the spoke unit 15, and the spoke unit 15 is fixed to the cylindrical unit 11. Therefore, the cylindrical unit 11, the spoke unit 15, and the shaft 13 are rotatably supported by the connecting arm 27 as a single unit.

[0028] The electrode section 17 is suspended from the shaft 13 in a rotatable manner. Specifically, the base end of the electrode holding arm 23 of the electrode section 17 is connected to the shaft 13 in a rotatable manner. As a more specific example of the structure, as shown in Figure 3(c), a through hole is provided at the base end of the electrode holding arm 23, and the shaft 13 is inserted through this through hole in a manner that allows for easy rotation. With this structure, the electrode section 17 takes on a posture in which the electrode 25 is pointed vertically downward by its own weight. The electrode 25 then slides against the inner circumferential surface 11b at a position vertically below the shaft 13. That is, due to gravity, the electrode 25 is positioned at the bottom of the inner circumferential surface 11b, facing the compaction surface S with the cylindrical wall 11p of the cylindrical section 11 in between. For example, a predetermined stopper (not shown) provided on the shaft 13 restricts the movement of the electrode section 17 in the direction of the rotation axis H, and the positional relationship of the four electrode sections 17 in the direction of the rotation axis H is maintained.

[0029] The cover portion 21 is fastened to the shaft end of the shaft 13 by a screw 22, and is rotatable relative to the shaft 13 and the screw 22, so the cover portion 21 does not rotate relative to the connecting arm 27 while the trolley 3 is in motion.

[0030] According to the configuration of the resistivity measuring device 1 described above, when the trolley 3 travels on a horizontal compacted surface S, the cylindrical part 11 rolls on the compacted surface S. At this time, as mentioned above, the electrode part 17 maintains a posture in which the electrode 25 is pointed vertically downward by its own weight. Therefore, the electrode 25 basically remains at the bottom of the inner circumferential surface 11b and is always positioned facing the compacted surface S with the cylindrical wall 11p in between. However, since frictional force from the inner circumferential surface 11b also acts on the electrode 25, the electrode 25 tends to move in the circumferential direction as it is dragged by the inner circumferential surface 11b. Due to the combined effect of these frictional forces, the position of the electrode 25 may shift in the circumferential direction from the bottom of the inner circumferential surface 11b while the trolley 3 is traveling. The displacement of the electrode 25 causes the characteristics of the electrical element composed of the electrode 25 and the cylindrical wall 11p to change. The control unit 10 should employ a calculation method that takes into account the effects of such displacement when calculating the resistivity.

[0031] Furthermore, due to unevenness in the compacted surface S, for example, it may not be possible to maintain constant contact between the outer surface 11a of the cylindrical portion 11 and the compacted surface S while the trolley 3 is in motion. As a countermeasure, the connecting arm 27 may have a suspension function. In this case, the suspension function of the connecting arm 27 presses the probe portion 5 against the compacted surface S, thereby maintaining constant contact between the outer surface 11a of the cylindrical portion 11 and the compacted surface S.

[0032] Furthermore, while the trolley 3 is in motion, the base end of the electrode holding arm 23 slides against the shaft 13, causing static electricity to accumulate on the shaft 13 due to this friction. To discharge this static electricity, the shaft 13 may be provided with a ground connection. Specifically, for example, one end of a predetermined grounding member (not shown) may be connected to the shaft 13, and the other end of the grounding member may be dragged along the compacted surface S while the trolley 3 is in motion.

[0033] Furthermore, if the frictional force between the outer circumferential surface 11a of the cylindrical portion 11 and the compaction surface S is weak, slippage may occur between the outer circumferential surface 11a and the compaction surface S, potentially preventing the cylindrical portion 11 from rolling correctly. To address this, a friction band 29 (high-friction region) of a predetermined width is provided on the outer circumferential surface 11a to increase the friction between the outer circumferential surface 11a and the compaction surface S. The friction band 29 is a portion of the outer circumferential surface 11a where the friction with the compaction surface S is greater than in other parts of the outer circumferential surface 11a. Multiple friction bands 29 are provided intermittently in a stripe pattern in the axial direction, forming a part of the outer circumferential surface 11a. For example, the friction band 29 is made of a material that has greater friction with the compaction surface S than the cylindrical portion 11 and is composed of a strip-shaped member wrapped around the outer circumferential surface 11a. For example, the friction band 29 is a rubber strip in the shape of a predetermined width.

[0034] A groove of a predetermined width extending around the entire circumference is formed on the outer circumferential surface 11a of the cylindrical portion 11, and a ring-shaped friction band 29 fits precisely into this groove. It is preferable that the outer circumferential surface of the friction band 29 is flush with the outer circumferential surface 11a of the cylindrical portion 11. The friction band 29 is provided in a region that does not overlap with the position of the electrode 25 in the axial direction, so as not to affect the electrical interaction between the electrode 25 and the cylindrical wall 11p and the compaction surface S. With such a friction band 29, an appropriate frictional force is ensured between the outer circumferential surface 11a of the cylindrical portion 11 and the compaction surface S, and this frictional force is applied to the cylindrical portion 11 as rotational torque, causing the cylindrical portion 11 to roll correctly on the compaction surface S.

[0035] The friction band 29 may occupy the entire outer surface 11a of the cylindrical portion 11. As a specific configuration, for example, the entire surface of the cylindrical portion 11 may be covered with a rubber member. With this configuration, it is expected that damage to the cylindrical portion 11 will be reduced and maintenance for wear will only require the replacement of the rubber member. Even if the outer surface of the cylindrical wall 11p is made of rubber, electrical interaction will occur between the electrode 25 and the cylindrical wall 11p and the compacted surface S, so resistivity can be measured.

[0036] Figure 4 is a schematic circuit diagram showing the electrical circuit comprising the embankment G, cylindrical section 11, four electrodes 25, and control unit 10 during the use of the resistivity measuring device 1. The control unit 10 has an AC power supply 31 and a potentiometer 33. The AC power supply 31 is connected between current electrode 25A and current electrode 25B, and the potentiometer 33 is connected between potential electrode 25C and potential electrode 25D. As described above, the four electrodes 25 are arranged in the order of current electrode 25A, current electrode 25B, potential electrode 25C, and potential electrode 25D, forming a dipole-dipole arrangement. The four electrodes 25 are each in contact with the compacted surface S of the embankment G via the cylindrical wall 11p of the cylindrical section 11, which is an electrical insulator.

[0037] During the use of the resistivity measuring device 1, the AC power supply 31 applies an AC voltage between the current electrode 25A and the current electrode 25B. As a result, the current electrode 25A and the cylindrical wall 11p, and the current electrode 25B and the cylindrical wall 11p each function as capacitors, causing an AC current to flow through the embankment G. The potential difference generated between the potential electrode 25C and the potential electrode 25D in response to this AC current is measured by the potentiometer 33. The control unit 10 then obtains the resistivity value of the embankment G by calculation based on the above AC voltage, the above potential difference, and the positional relationship between the four electrodes 25 (distance between each electrode 25, etc.). Since resistivity measurement using this dipole-dipole method is well known, further detailed explanation is omitted.

[0038] The resistivity measurement method employed in resistivity measuring device 1 can be any four-electrode method using a pair of current electrodes and a pair of potential electrodes, and is not limited to the dipole-dipole method. In other words, by changing the arrangement of electrodes 25A to 25D, other resistivity measurement methods can also be employed in resistivity measuring device 1. For example, other resistivity measurement methods such as the pole-pole method, pole-dipole method, Wenner method, and Schlumberger method may be employed in resistivity measuring device 1.

[0039] The effects of the resistivity measuring device 1 of this embodiment, as described above, will now be explained. In the resistivity measuring device 1, as shown in Figure 2, a cylindrical portion 11 is used as an insulating member interposed between the electrode 25 and the compaction surface S. Since the cylindrical portion 11 rolls on the compaction surface S, wear due to contact with the compaction surface S is suppressed to a smaller extent compared to, for example, an insulating member that slides on the compaction surface S. As a result, the frequency of replacement and maintenance of the cylindrical portion 11, which is the insulating member, can be reduced.

[0040] Furthermore, in the resistivity measuring device 1, the cylindrical portion 11 is separated from the electrode 25. Therefore, even if the cylindrical portion 11 is worn or damaged, the function of the resistivity measuring device 1 can be restored simply by replacing the cylindrical portion 11.

[0041] Furthermore, the presence of the friction band 29 allows the cylindrical portion 11 to roll correctly on the compaction surface S, making it difficult for slippage to occur between the outer circumferential surface 11a and the compaction surface S. This effectively reduces wear on the cylindrical portion 11 as described above.

[0042] Furthermore, in the resistivity measuring device 1, the electrode 25 is not fixed to the cylindrical portion 11. During the movement of the trolley 3, the electrode 25 maintains its position facing the compaction surface S due to gravity and does not rotate relative to the compaction surface S or the vehicle body 7. With this configuration, the electrode 25 and the control unit 10 on the vehicle body 7 can be connected by ordinary conductive wires 19 without the need for slip rings or the like.

[0043] The present invention can be implemented in various forms, including the embodiments described above, by making various changes and improvements based on the knowledge of those skilled in the art. Furthermore, it is possible to construct modified versions by utilizing the technical matters described in the embodiments described above. The configurations of each embodiment may be used in appropriate combinations.

[0044] As shown in Figure 5, the number of electrodes 25 provided in the probe unit 5 may be changed as appropriate. For example, the probe unit 5A shown in Figure 5(a) has only one electrode unit 17, that is, only one electrode 25. Since the resistivity measuring device 1 based on the four-electrode method requires a total of four electrodes 25, consisting of at least one pair of current electrodes 25A, 25B and one pair of potential electrodes 25C, 25D, in this case, the resistivity measuring device 1 only needs to have at least four probe units 5A, each containing one of the electrodes 25A to 25D. Also, for example, the probe unit 5B shown in Figure 5(b) has two electrode units 17, that is, two electrodes 25. In this case, the resistivity measuring device 1 only needs to have at least two probe units 5B, and the four electrodes 25A to 25D can be appropriately distributed among the two probe units 5B. Components of probe units 5A and 5B that are the same as or equivalent to components of probe unit 5 are denoted by the same reference numerals in the drawings, and redundant explanations are omitted.

[0045] As for the specific arrangement of the multiple probe sections 5A and 5B as described above, for example, as shown in Figure 6(a), four probe sections 5A may be arranged in a straight line in the direction of travel on the underside of the vehicle body 7. Alternatively, for example, as shown in Figure 6(b), four probe sections 5A may be arranged in a straight line in the vehicle width direction on the underside of the vehicle body 7. Furthermore, for example, as shown in Figure 6(c), two probe sections 5B may be arranged in a straight line in the vehicle width direction on the underside of the vehicle body 7.

[0046] Furthermore, the resistivity measuring device 1 may be equipped with multiple trolleys 3 that are towed in series, and the necessary probe units 5A and 5B may be distributed and installed on these multiple trolleys 3. For example, the resistivity measuring device illustrated in Figure 6(d) is equipped with two trolleys 3 connected in a chain-like fashion by a traction wire 35. Two probe units 5A are arranged on each trolley 3, and a total of four probe units 5A are arranged in a straight line in the direction of travel.

[0047] In the four-electrode method, the positional relationship of the four electrodes 25 (such as the distance between each electrode 25) must be known. As long as this positional relationship is known, the number and arrangement of the trolley 3, probe units 5, 5A, 5B, and electrodes 25A to 25D can be freely changed, not limited to the examples in Figures 6(a) to (d). For example, when there are multiple trolleys 3 being towed in series (e.g., Figure 6(b)), a traction wire 35 of known length is used to make the positional relationship between the probe units 5, 5A, 5B attached to each trolley 3 known.

[0048] Furthermore, although the shaft 13 (see Figure 2, etc.) is a rotating shaft that rotates while the trolley 3 is running, the shaft 13 may also be a fixed shaft fixed to the connecting arm 27. In this case, the spoke portion 15 and the cylindrical portion 11 should be supported rotatably on the shaft 13 as a single unit. The electrode portion 17 should be fixed to the shaft 13 in a position such that the electrode 25 faces the compaction surface S. The cover portion 21 should be fixed to the shaft end of the shaft 13. With such a mechanism, while the trolley 3 is running, the electrode 25 is located at the bottom of the inner circumferential surface 11b and is positioned facing the compaction surface S with the cylindrical wall 11p of the cylindrical portion 11 in between. [Explanation of Symbols]

[0049] 1... Resistivity measuring device, G... Embankment, S... Compacted surface, 3... Traveling trolley, 5, 5A, 5B... Probe section, 11... Cylindrical section (insulating member), 11p... Cylindrical wall, 11q... Hollow section, H... Rotation axis, cylindrical axis, 13... Shaft, 17... Electrode section, 19... Conductive wire, 11b... Inner circumferential surface, 25... Electrode, 25A, 25B... Current electrode, 25C, 25D... Potential electrode, 27... Connecting arm (connecting section), 29... Friction zone (high friction region).

Claims

1. A resistivity measuring device comprising a probe section having an insulating member that contacts the ground surface of the ground to be measured, and an electrode connected to the ground via the insulating member, wherein the resistivity of the ground is measured while moving along the ground surface, The insulating member has a cylindrical shape that rolls on the ground, Resistivity measuring device, wherein the electrode is disposed within the cylindrical hollow portion of the insulating member, slides against the inner circumferential surface of the cylinder of the insulating member, and is positioned facing the ground with the cylindrical wall of the insulating member in between.

2. The probe portion is A shaft extending along the cylindrical axis of the insulating member and fixed to the insulating member, It has an electrode portion that is rotatably suspended from the shaft at one end and has the electrode at the other end, The resistivity measuring device according to claim 1, wherein the electrode portion takes a position with the electrode facing vertically downward due to its own weight.

3. The aforementioned trolley that moves on the ground, The system further comprises a connecting part that connects the aforementioned traveling carriage and the aforementioned probe part, The resistivity measuring device according to claim 2, wherein the connecting portion rotatably supports the shaft.

4. The resistivity measuring device according to claim 3, further comprising a conductive wire drawn out from the electrode for electrical connection between the electrode and other devices on the trolley.

5. The system comprises a pair of current electrodes for applying an alternating current voltage to the ground, and a pair of potential electrodes for measuring the potential difference generated in the ground in response to the alternating current voltage. The resistivity measuring device according to claim 1, wherein at least one of the pair of current electrodes and the pair of potential electrodes is included as the electrode in the probe portion.

6. The resistivity measuring device according to claim 1, wherein the outer circumferential surface of the insulating member is provided with a high-friction region for increasing friction between the outer circumferential surface and the ground.

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