JP2002202382A - Measuring method for resistivity and device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring method for resistivity and a device thereof capable of easily and continuously measuring resistivity of a specimen. SOLUTION: An electric potential is given to the specimen S and a pair of electrodes C and P1 to 3 are contacted to the specimen S to measure the resistivity at each portion of the specimen S. For the electrodes C and P1 to 3, a dolly 10 provided with electrode wheels where wires for example are arranged are used. By rotating the electrode wheels of the dolly 10, the measuring points of the specimen S are changed in turn.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring a specific resistance as seen in the so-called specific resistance imaging method, and to a specific resistance measuring apparatus used for the method. More specifically, the present invention relates to a method for applying a potential to a test body and bringing a pair of electrodes into contact with the test body to measure the specific resistance at each part of the test body, and a measuring device used for the method.

[0002]

2. Description of the Related Art Conventionally, a specific resistance measuring method, which is a kind of specific resistance measuring method, is generally used for the purpose of knowing a rough specific resistance of a rather large object such as a geological survey. When the resistivity imaging method is used for a concrete structure or the like, conductive rubber is attached to the surface of the concrete as an electrode, or a flat plate electrode is fixed with clay. And
If the electrode is to be sufficiently brought into electrical contact with concrete or the like, a large contact area must be ensured, and the electrode must be widened.

Therefore, in order to carry out the specific resistance imaging under the above-mentioned conventional electrode contact method, it was not possible to secure a high number of measurement points. As a result, the technique can only be used for fairly rough measurements, and the word exploration can tell that point.

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned conventional circumstances, the present invention provides a specific resistance measuring method and a specific resistance measuring apparatus capable of simply and continuously measuring the specific resistance of a test specimen. Is to do.

[0005]

In order to achieve the above object, a method of measuring resistivity according to the present invention is characterized in that a potential is applied to a specimen, and a pair of electrodes are brought into contact with the specimen so as to contact the specimen. In the method for measuring the specific resistance at each part, at least one of the electrodes is an electrode wheel made of a conductive elastic body, and the measurement part of the test body is sequentially changed by rolling the electrode wheel. It is in.

[0006] According to this configuration, since the electrode wheel is made of a conductive elastic body, a good contact state with the surface of concrete or a steel structure can be obtained. Then, the rolling of the electrode wheel causes the wheel itself to bite into the surface of the test specimen, so that stable and continuous measurement can be performed.

Preferably, a plurality of the electrode wheels are provided on a truck, and the truck is moved by rolling of the electrode wheels, and the plurality of electrode wheels are selected at each position of the truck to select every one channel or a plurality of channels. The measurement may be performed in parallel. By using both of the pair of electrodes as the plurality of electrode wheels, the specific resistance between the electrode wheels can be obtained while moving the truck.

On the other hand, the feature of the specific resistance measuring apparatus according to the present invention is that, when a potential is applied to the specimen and a pair of electrodes are brought into contact with the specimen, the specific resistance at each part of the specimen is measured. In the configuration used in the above, a bogie having a plurality of wheels is provided, at least one of the wheels is an electrode wheel made of a conductive elastic body corresponding to the electrode, and the test piece is formed by rolling the electrode wheel. Are to be sequentially changed.

Here, it is preferable that the truck has a plurality of electrode wheels, and the plurality of electrode wheels are insulated from each other. In addition, as long as at least one pair of the electrode wheels can change the distance between each other, it is possible to continuously change the depth of the measurement site of the specific resistance.

The electrode wheel may be configured by arranging wires radially around an axis. The wire has an elastic force and is arranged radially so that the tip of the wire has fine irregularities that enter into the surface irregularities of concrete or a steel structure, and a very good contact state can be stably obtained.

[0011]

As described above, according to the characteristics of the specific resistance measuring method and the specific resistance measuring apparatus according to the present invention, a good contact state can be continuously ensured even with a small contact area by using the electrode wheels. It became so. As a result, the specific resistance of the test specimen can be easily and continuously measured, and the inspection of a concrete structure or a steel structure can be performed more easily.

Other objects, configurations and effects of the present invention will become apparent in the following embodiments of the present invention.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a first embodiment of the present invention will be described with reference to FIGS. The test object S to which the present embodiment is applied includes any structure such as a concrete structure, a structure using a steel member, and a bedrock.

As shown in FIG. 6, a specific resistance measuring apparatus 1 according to the present invention includes a carriage 10 and a control unit 60. The cart 10 has electrode wheels 31 to
34, eight electrode wheels 30 are provided. Then, a voltage is applied between the first electrode wheel 31 (C) and the ground 66 (D), and the second electrode wheel 32 (P1) is connected to the ground 69 (D1).
By measuring the potential between (Q) and
The measurement of the specific resistance between these is indicated by 1a.

As a power supply 61 in the control unit 60, an inverter power supply having an AC rectangular wave and a single voltage of 100 V or 150 V can be used. The power supply 61 is connected to an application-side voltmeter 63 connected in parallel with a shunt resistor 62. The applied current by 61 is measured. First electrode wheel 31 of cart 10
A voltage is applied between (C) and the ground 66 (D).

The second electrode wheel 32 (P1), the third electrode wheel 33 (P2), and the fourth electrode wheel 34 (P3) are independent electrodes, and are measured so that the voltage can be read by the measuring voltmeter 68. It is selectively used by switching the side relay 67. The other electrode of the measurement-side voltmeter 68 is a ground 69
(Q) connects to the specimen S. In addition, earth 6
It is desirable that the piles 6 and 69 ensure sufficient electrical contact without damaging the specimen S using clay or the like without driving the pile into the specimen S.

As will be described later, the distance between the third electrode wheel 33 and the fourth electrode wheel 34 can be changed by a slide mechanism 50, and the motor 56 of the slide mechanism 50 is driven and controlled by a motor controller 70. The traveling distance of the carriage 10 may be measured by actual measurement using a scale or the like.
It is also possible to measure with.

The test piece S may correspond to, for example, an inner wall of a tunnel, and it is necessary to bring the bogie 10 into contact with the test piece S from below. In this case, for example, the carriage may be supported and moved by the robot arm mechanism, and the coordinate address of the carriage 10 can be derived from the driving amount of the robot arm.

Here, the distance of P1 (c) is a, C and D
Is L1, the distance between P and Q is L2. This embodiment employs a so-called bipolar arrangement, in which case B
And Q are far electrodes, and the distances L1 and L2 need to be ten times or more than a.

The potential V of P1 due to C is as follows. V = ρI / 2πa (1)

Therefore, the specific resistance ρ of the test sample S between CP1 is as follows. ρ = 2πaV / I (2)

With this principle, the specific resistance between CP1 can be obtained, and the specific resistance between different electrodes can be measured by sequentially selecting the measurement side relays 67, P2 and P3.

Next, referring to FIGS.
Will be described. The carriage 10 has a main frame 20,
An electrode wheel 30, a slide frame 40, and a slide mechanism 50 are provided. The main frame 20 joins both ends of the square frames 21 and 21 made of two insulators by connecting frames 22 and 22 which are insulators, and forms a basic portion thereof. An insulating plate 23 is fixed to the lower surface of the front part of the main frame 20, and the electrode wheels 30 are respectively attached by small angles 24. That is, left first electrode wheel 31a, right first electrode wheel 31b, left second electrode wheel 32
a, the right second electrode wheel 32b is insulated from each other.

As shown in FIG. 2, the electrode wheel 30 is connected to the axle 3
5, a number of wires 37 are arranged radially around the disk 3
6 is fixed. Then, as shown in FIG. 5, a pair of electrode wheels 30 is inserted into each of the small angles 24, 24, and the axles 35, 35 are connected to each other by a resin coupler 39, which is an insulator. Insulation is ensured.

As shown in FIGS. 1, 3 and 4, the slide frame 40 has a pair of small angles 42, 4 under an insulating plate 41.
2 is provided. Then, similarly to the above, a pair of electrode wheels 30, 30 is individually attached to each small angle 42. On the other hand, the slide mechanism 50 includes a slide block 51 that supports the slide frame 40 slidably in the longitudinal direction of the main frame 20. The slide block 51 has two slide bars 52, 52, and the slider 53 slides along the slide bars 52, 52. The slide frame 40 is a T-shaped angle 4
3 is attached to the slider 53.

The left third electrode wheel 33a and the right third electrode wheel 33b, which are arranged following the left second electrode wheel 32a at the same interval as the interval between the left first electrode wheel 31a and the left second electrode wheel 32a, Each angle frame 2 by large angle 26,26
It is attached under 1,21. Square frames 21, 21
Is an insulator, the left third electrode wheel 33a and the right third electrode wheel 33b are also insulated from each other. The space between the left third electrode wheel 33a and the right third electrode wheel 33b is wider than the space between the other coaxial electrode wheels 30, and the slide frame 40 is received therebetween.

As shown in FIGS.
0 further drives the driven piece 54 back and forth by the motor 56 in the slide rail 55. The driven piece 54 is fixed to the slider 53, and arbitrarily changes the distance W between the third electrode wheel 33 and the fourth electrode wheel 34.

Next, the measurement of the specific resistance of the bipolar electrode arrangement will be described in more detail with reference to FIGS. FIG.
Then, for convenience, the left electrode wheels 31a to 34a in FIG.
And the right electrode wheels 31b to 34b are collectively described as electrode wheels 31 to 34. That is, the left first electrode wheel 31a and the right first electrode wheel 31b are collectively described as the first electrode wheel 31 for explanation.

First, as shown in FIG.
Q is brought into contact with the specimen S, and the carriage 10 is brought into contact with the specimen S. The electrode C is the first electrode wheel 31, and a voltage is applied between the electrodes CD by the power supply 61. Then, the measurement side electrode sets the second electrode wheel 32 to P by the measurement side relay 67.
1, and the specific resistance in the vicinity of the point R1a between C and P1 is obtained by the above equation (2). If the third electrode wheel 33 is selected as P2 according to 7, the specific resistance in the vicinity of the point R1b between C and P2 can be similarly obtained. If the fourth electrode wheel 34 is located at the rightmost position and is selected as P3, the specific resistance near the point R1c can be obtained.
However, when the distance W between the third electrode wheel 33 and the fourth electrode wheel 34 is changed by driving the slide mechanism 50, the specific resistance in the vicinity of the portion along the line segment R1d between R1b and R1c may be obtained. it can.

Next, as shown in FIG.
0 is moved by the pitch a of each electrode wheel 30, for example, and the same operation is performed. Thereby, the specific resistances in the vicinity of the points R2a to R2c and in the vicinity of the line segment R2d can be obtained.

So far, the measurement in which the carriage 10 is intermittently moved to switch P1 to P3 has been described. In the example shown in FIG. 8, the carriage 10 is continuously moved while P1 to P3 are switched and the measurement is constantly performed. The measurement points in such measurement are intermittent points R1a, R2a,
Unlike R1b and R2b, they are continuous as shown by lines Ra and Rb. When the fourth electrode wheel 34 is reciprocated by simultaneously driving the slide mechanism 50 while continuously measuring while moving the carriage 10, the line segment R in FIG.
1d and R2d depict trochoids and cycloids indicated by reference numeral Rd in FIG.

Next, referring to FIG. 4, the measurement points when the eight electrode wheels 30 are used again will be described.
First, in the case where the left first electrode wheel 31a is the C electrode and the electrode wheel 30 in row A is used, when the left second electrode wheel 32a is used as P1, the points RA1 and P2 are used as the left third electrode wheel. When using 33a, the points RA2, P
When the left fourth electrode wheel 34a is used as 3, the point RA
Measurement values at plane coordinates respectively corresponding to 3 are obtained.

When the left first electrode wheel 31a is used as the C electrode and the electrode wheel 30 in the B row is used, P
When the right second electrode wheel 32b is used as 1, the point RA
When the right third electrode wheel 33b is used as B1 and P2, measured values at plane coordinates corresponding to the point RAB2 when the right fourth electrode wheel 34b is used as the point RAB3 are obtained. The measurement value at the coordinates of RAB0 may be obtained with the right first electrode wheel 31b as the point P. It is of course possible to change the positions of RA3 and RAB3 by changing the position of the fourth electrode wheel 34. The right first electrode wheel 31b may be used as a C electrode, and any of the electrode wheels 30 in row B or row A may be used as a P electrode. As described above, according to the above configuration, it is possible to measure the specific resistance in the plane direction and the depth direction, and thereby, it is possible to three-dimensionally inspect the specimen S.

Finally, still another embodiment of the present invention will be listed. The same members as those in the above-described embodiment are denoted by the same reference numerals. In the above embodiment, the electrode wheel 3
0 was constituted by a steel wire 37. But,
The electrode wheel 30 can be constituted by a conductive member wire 37 such as carbon or conductive plastic. The electrode wheel 30 may be formed of an elastic conductive member. For example, the electrode wheel 30 may be formed by winding a conductive member such as conductive rubber or steel wool around a shaft or a disk. However, from the viewpoint of good contact and durability with concrete and cast iron surfaces,
It is most desirable to use electrode wheels 30 with radially arranged wires. It should be noted that fine irregularities can be formed on the surface of the wire or steel wool, and this penetrates into the irregularities on the surface of the test specimen.

In the above embodiment, all the wheels are connected to the electrode wheels 30.
And However, some of the wheels may be electrode wheels 30 and the rest may be rubber or plastic rolling wheels.

In the above embodiment, the C electrode is fixed to the first electrode wheel 31. However, the C electrode is an electrode wheel 31-34.
, Or a C electrode may be provided outside the carriage 10.

In the above embodiment, the measurement was performed for each channel by selecting the plurality of electrode wheels 30 at each carriage position. However, it is also possible to provide the measuring-side voltmeter 68 for a plurality of channels, or to switch the multi-channel by a clock using a personal computer and perform the above-described measurement in parallel on the plurality of channels.

In the above embodiment, only one truck is used. However, using two trucks, one of them has a C electrode,
A P electrode may be provided on another element.

In the above embodiment, the present invention is implemented as a so-called bipolar arrangement, but the present invention is not limited to this. In the triode method shown in FIG. 9, for example, the earth 66 in FIG. 6 is set to the D pole, the first electrode wheel 31 is assigned to the C pole, the second electrode wheel 32 is assigned to the P pole, and the third electrode wheel 33 is assigned to the Q pole. And good. The following equation is established between the C and P poles instead of the above equation (2). ρ = 2n (n + 1) πaV / I (3)

In the quadrupole method shown in FIG. 10, for example, the first electrode wheel 31 of FIG. 6 has a C pole, the second electrode wheel 32 has a D pole, the third electrode wheel 33 has a Q pole, and the fourth electrode wheel 34 has a P pole. It is good to assign to each pole. D · Q instead of equation (2)
The following equation is established between the poles. ρ = n (n + 1) (n + 2) πaV / I (4)

In the weenna arrangement shown in FIG. 11, for example,
The first electrode wheel 31 of FIG.
The pole and the third electrode wheel 33 may be assigned to the Q pole, and the fourth electrode wheel 34 may be assigned to the D pole. The following equation holds between the P and Q poles instead of the above equation (2). ρ = n (n + 1) (n + 2) πaV / I (5)
It should be noted that reference numerals written in the claims are merely for convenience of comparison with the drawings, and the present invention is not limited to the configuration of the attached drawings by the writing.

[Brief description of the drawings]

FIG. 1 is a carriage used in a specific resistance measuring apparatus according to the present invention.

FIG. 2 is a side view of an electrode wheel.

FIG. 3 is a sectional view taken along line AA of FIG. 1;

FIG. 4 is a plan view of the cart.

FIG. 5 is a sectional view taken along line BB of FIG. 1;

FIG. 6 is a block diagram of an apparatus for measuring a specific resistance according to the present invention.

FIG. 7 is a schematic view of an apparatus for measuring a specific resistance showing a procedure for implementing the present invention.

FIG. 8 is a diagram showing a path of a measurement point.

FIG. 9 is a principle diagram of a triode method used in another embodiment of the present invention.

FIG. 10 is a principle diagram of a quadrupole method used in another embodiment of the present invention.

FIG. 11 is a view showing the principle of a weenna arrangement used in another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Apparatus for resistivity measurement 10 Bogie 20 Main frame 21 Square frame 22 Connecting frame 23 Insulating plate 24 Small angle 25 Small block 26 Large angle 30 Electrode wheel 31 First electrode wheel (31a left first electrode wheel, 31b
Right first electrode wheel 32 Second electrode wheel 32a Left second electrode wheel 32b
Right second electrode wheel 33 33 Third electrode wheel (33a Left third electrode wheel, 33b
Right third electrode wheel) 34 fourth electrode wheel (34a left fourth electrode wheel, 34 right fourth electrode wheel) 35 axle 36 disk 37 wire 38 wheel body 39 resin coupler 40 slide frame 41 insulating plate 42 small angle 43 T-shaped Angle 50 Slide mechanism 51 Slide block 52 Slide bar 53 Slider 54 Follower piece 55 Slide rail 56 Motor 60 Control unit 61 Power supply 62 Shunt resistor 63 Applied voltmeter 64 Diode 65 Applied relay 66 Ground 67 Measurement relay 68 Measurement voltmeter 69 Ground 70 Motor controller 80 Encoder S Specimen

Claims (7)

[Claims] An electric potential is applied to the specimen (S), and a pair of electrodes (C, P1 to P3) are brought into contact with the specimen (S) so that the specific resistance at each part of the specimen (S) is reduced. A method of measuring a specific resistance, wherein at least one of the electrodes (C, P1 to 3) is an electrode wheel (30) made of a conductive elastic body (37), and the electrode wheel (30) is rolled. A specific resistance measuring method for sequentially changing the measurement site of the test body (S) by moving the test body (S). 2. A plurality of electrode wheels (30) are provided on a trolley (10), the trolley (10) is moved by rolling of the electrode wheels (30), and the plurality of electrode wheels (30) are provided at each trolley position. The method according to claim 1, wherein 30) is selected to perform the measurement for each channel or in parallel for a plurality of channels. 3. The specific resistance measuring method according to claim 2, wherein the pair of electrodes (C, P1 to P3) are both the plurality of electrode wheels (30). 4. A test body (S) is given an electric potential, and a pair of electrodes (C, P1 to 3) is brought into contact with the test body (S) to reduce the specific resistance at each part of the test body (S). A specific resistance measuring device used for measurement, comprising a carriage (10) having a plurality of wheels, at least one of the wheels being a conductive elastic body corresponding to the electrodes (C, P1 to P3). An electrode wheel (30) consisting of (37), and a specific resistance measuring device for sequentially changing the measurement site of the test body (S) by rolling the electrode wheel (30). 5. The truck (10) is mounted on the electrode wheel (3).
5. The apparatus for measuring a specific resistance according to claim 4, comprising a plurality of 0), wherein the plurality of electrode wheels (30) are insulated from each other. 6. The device for measuring a specific resistance according to claim 5, wherein at least one pair of the electrode wheels (30) is capable of changing a mutual distance. 7. The method according to claim 1, wherein the electrode wheel (30) is formed by radially arranging wires (37) around an axis (35). The apparatus for measuring a specific resistance according to any one of 4 to 6.