JP2020176429A - Monitoring system and monitoring method - Google Patents

Abstract

To determine a cause of insufficient protection potential when electrolytic protection is performed on a steel foundation beam.SOLUTION: The monitoring system comprises: a concrete pile that is embedded in the ground and in which a plurality of pile reinforcements are arranged; a concrete bottom slab that is set on the surface of the ground and in which a plurality of slab reinforcements are arranged; and a steel foundation part that connects the pile and bottom slab, and at least part of which is embedded in the ground. The foundation part comprises: a steel pile head joint part that is connected to an upper end of the pile; a steel support part that extends upward from the pile head joint part; a current supply part that extends horizontally from the support part and supplies currents to foundation beams of a foundation structure including steel foundation beams that support the bottom slab; a receiving part that receives potential to ground information for foundation beams of the foundation structure; and a processing part that, based on potential to ground information, performs one of or both of the following: determination of whether low earth objects contact foundation beams and determination of whether the outflow of currents is occurring due to interference with stray currents.SELECTED DRAWING: Figure 4

Description

Embodiments of the present invention relate to monitoring systems and monitoring methods.

Conventionally, for example, a basic structure as shown in Patent Document 1 is known. This foundation structure is made of concrete piles buried in the soil and having multiple slab reinforcing bars inside, and concrete piles installed on the surface of the soil and having multiple slab reinforcing bars inside. It has a floor slab, a steel foundation that connects the pile and the floor slab, and at least partly buried in the soil.
The foundation consists of a steel pile head joint connected to the upper end of the pile, a steel strut extending upward from the pile head joint, and a floor slab extending horizontally from the strut. It is equipped with a supporting steel foundation beam.
In this foundation structure, not only microcell corrosion in general soil but also concrete soil macrocell corrosion (hereinafter referred to as "CS macrocell corrosion") occurs. In this foundation structure, since the pile reinforcing bar or slab reinforcing bar and the foundation portion are conducted, a potential difference is generated between them, the foundation portion becomes an anode, and an anode reaction occurs at the foundation portion to cause the pile reinforcing bar or slab. Reinforcing bars serve as cathodes, and cathode reactions occur in pile reinforcing bars and slab reinforcing bars, and corrosion current flows from the anode to the cathode through the soil, causing CS macrocell corrosion in the foundation, which is the anode. At this time, the potential of the base portion shifts to your side.
In order to prevent CS macrocell corrosion and microcell corrosion, there is a technique of applying coating to a steel base and further applying electrocorrosion protection such as a magnesium alloy anode. In this technology, when a sufficient anticorrosion current density flows into the coating defect of the steel foundation, the ground potential of the steel foundation on your side shifts to the base side, and the ground potential is on the base side of the anticorrosion potential. Then, corrosion protection of the steel foundation is achieved.
In electrocorrosion, the required anticorrosion current generator (eg, magnesium alloy anode) is designed so that the required anticorrosion current density can be supplied to the target steel foundation.
However, when another metal object comes into contact with the target steel base, the anticorrosion current generated from the magnesium alloy anode also flows into other metal objects other than the target steel foundation, so that corrosion protection is inherently achieved. The required anticorrosion current density of the steel base is below the value that reaches the anticorrosion potential. Therefore, although the steel foundation is provided with electrocorrosion protection, the corrosion protection potential is not reached due to metal contact with other metal objects, and corrosion occurs. At this time, the generated current of the magnesium alloy anode in the vicinity of the metal contact portion increases. Other metal objects that come into contact with the steel foundation include lead-in pipes to steel buildings, leftover metal objects for construction work, and other metal objects in the soil.
In addition, if a steel foundation is installed in the soil where the stray current is flowing due to a DC electric railway, etc., the stray current will be a concrete pile including the steel foundation, which is a low grounding structure. It flows in and out of the magnesium alloy anode. At the place where the stray current flows in, the potential shifts to the base side and the same anticorrosion effect as electrocorrosion is obtained, but at the place where it flows out, the ground potential shifts to your side and stray current corrosion (electrocorrosion) occurs. Occur. The phenomenon in which the ground potential of an object shifts to the base side or your side due to the inflow and outflow of stray current is called interference.
At this time, when the stray current flows into the magnesium alloy, the ground potential of the anode is lowered and the generated current of the anode is suppressed, but when the stray current flows out of the magnesium alloy, the ground potential of the anode is suppressed. However, the generated current of the anode increases by the stray current, and the dissolution of the anode progresses by the increase of the current. Therefore, there is a problem that the anode is consumed before the useful life of the anode expected in the anode design.

Japanese Unexamined Patent Publication No. 2005-068953

Even if the steel foundation is electrolytically protected, it is assumed that the steel foundation does not reach the corrosion protection potential for the reasons described above. The reason why the steel foundation does not reach the anticorrosion potential is that all steel materials (mainly reinforcing bars) that conduct with the steel foundation come into contact with other metal objects (low grounding objects), and stray from electric railways, etc. It is assumed that stray current will flow out due to current interference.
However, it is difficult to identify the location where the anticorrosion potential of the steel foundation is not reached and the cause. For this reason, in the pipeline, a technique for detecting a portion that does not reach the anticorrosion potential is being developed. For example, there is a magnetic sensor method as one of the methods for detecting the contact position when there is contact with another metal in the pipeline. In this method, a current is passed through the pipeline, and the magnetic field generated by the current flowing through the pipeline is continuously measured along the pipeline with a magnetic sensor, but the current flowing through the pipeline branches at the metal contact point. Therefore, the magnitude of the magnetic field changes before and after the contact, and the contact position with the metal object is detected from the bending point of the magnitude of the magnetic field. This method is effective for simple stretched structures such as pipelines, but for complex structures such as steel foundations, even if an electric current is passed through the steel foundation to measure the magnetic field, the members will work together. Due to the overlapping magnetic fields, it is impossible to detect the contact position of a metal object. Thus, the technology developed in the pipeline cannot be applied to steel foundations.

The present invention has been made in view of the above-mentioned circumstances, and provides a monitoring system and a monitoring method capable of identifying the cause of the foundation portion not reaching the anticorrosion potential when the steel foundation portion is electrolytically protected. The purpose is to provide.

(1) The monitoring system according to one aspect of the present invention includes a concrete pile buried in the soil and having a plurality of pile reinforcements arranged inside, and a plurality of monitoring systems installed on the surface of the soil and inside. A concrete floor slab on which the slab reinforcements of the above are arranged, and a steel foundation portion connecting the pile and the floor slab and at least partially buried in the soil, said foundation portion. Supports the floor slab as well as a steel pile head joint connected to the upper end of the pile, a steel strut extending upward from the pile head joint, and extending horizontally from the strut. A current supply unit that supplies an anticorrosion current to the foundation portion of the foundation structure including a steel foundation beam, a reception unit that receives information indicating the ground potential of the foundation portion of the foundation structure, and the reception unit accepts information. Based on the information indicating the ground potential, it is determined whether or not a low ground object is in contact with the foundation, and whether or not a current outflow due to the interference of stray current is occurring in the steel foundation. It is provided with a processing unit that performs either one or both of the determinations.

According to the present invention, the monitoring system receives information indicating the ground potential of a steel foundation beam of the foundation structure. For this reason, in the monitoring system, based on the information indicating the received ground potential, the base part is in contact with a low grounded object, and the current outflow point is generated in the steel base part due to the interference of the stray current. Determine one or both of the presence.

(2) The monitoring system according to one aspect of the present invention is the monitoring system according to (1) above, the reception unit receives information indicating the anticorrosion current generated by the anode, and the processing unit receives the reception. Further, based on the information indicating the anticorrosion current received by the unit, it is determined whether or not a low grounded object is in contact with the foundation portion, and whether or not a current outflow occurs due to the interference of the stray current. Do one or both of the above.

In this case, the reception unit receives information indicating the anticorrosion current generated by the anode. Therefore, in the monitoring system, based on the information indicating the received anticorrosion current, the base part is in contact with the low grounded object, and the current outflow point is generated in the steel base part due to the interference of the stray current. Determine one or both of the items.

(3) The monitoring system according to one aspect of the present invention is the monitoring system according to (1) or (2) above, and the reception unit is the above-mentioned basic unit of each of the plurality of basic structures. The monitoring system receives information indicating the ground potential, and the monitoring system contacts the base with a low ground object based on the information indicating the ground potential of each of the foundations of the plurality of foundation structures received by the reception. It is provided with a specific part for deriving one or both of the derivation of the position where the current is occurring and the position where the current outflow occurs due to the interference of the stray current.

In this case, the monitoring system receives information indicating the ground potential of each foundation beam of the plurality of foundation structures. Therefore, the monitoring system determines whether the foundation beam is in contact with the low grounded object or the position where the current outflow occurs due to the interference of the stray current, based on the information indicating the plurality of received ground potentials. One or both can be derived.

(4) The monitoring system according to one aspect of the present invention is the monitoring system according to (3) above, and the specific unit is based on a plane defined by information indicating the ground potential at at least three locations. , One or both of the derivation of the position where the low grounded object is in contact with the base portion and the derivation of the position where the current outflow due to the interference of the stray current is generated.
In this case, the monitoring system receives information indicating at least three potentials to the ground. For this reason, the monitoring system derives the position where the low ground object is in contact with the foundation based on the plane defined by the information indicating the ground potential at at least three points received, and the current outflow due to the interference of the stray current. Either or both of the derivation of the position where is occurring is performed.

(5) The monitoring system according to one aspect of the present invention is the monitoring system according to (1) above, and in the reception unit, each of the plurality of current supply units is the basis of each of the plurality of basic structures. By supplying a current to the unit, information indicating the anticorrosion current generated by each of the plurality of anodes is received, and based on the information indicating the anticorrosion current generated by each of the plurality of anodes received by the reception unit. The base portion is provided with a specific portion that derives one or both of a position where a low ground contact object is in contact with the base portion and a position where a current outflow occurs due to interference of a stray current.
In this case, the monitoring system receives information indicating the anticorrosion current generated by each of the plurality of anodes. Therefore, the monitoring system derives the position where the low grounded object is in contact with the foundation based on the information indicating the anticorrosion current generated by each of the received plurality of anodes, and causes the current outflow due to the interference of the stray current. Either or both of the derivation of the generated position is performed.

(6) The monitoring method according to one aspect of the present invention includes a concrete pile buried in the soil and having a plurality of pile reinforcing bars arranged inside, and a plurality of monitoring methods installed on the surface of the soil and inside. A concrete floor slab on which the slab reinforcing bars of the above slab are arranged, and a steel foundation portion connecting the pile and the floor slab and at least partially buried in the soil, said foundation portion. Supports the floor slab as well as a steel pile head joint connected to the upper end of the pile, a steel strut extending upward from the pile head joint, and extending horizontally from the strut. A step of supplying a current to the foundation portion of a foundation structure including a steel foundation beam, a step of receiving information indicating the ground potential of the foundation portion of the foundation structure, and a step of receiving the ground potential received in the receiving step. Based on the information indicating the above, one or both of the determination of whether or not a low ground object is in contact with the foundation portion and the determination of whether or not a current outflow occurs due to the interference of stray current is performed. It is a monitoring method executed by a monitoring system having steps.

(7) The monitoring method according to one aspect of the present invention is the monitoring method according to (6) above, and in the receiving step, information indicating the ground potential of each of the foundation parts of the plurality of foundation structures. In the monitoring method, the position where the low ground contact object is in contact with the foundation portion is based on the information indicating the ground potential of each of the foundation portions of the plurality of foundation structures received in the acceptance step. It has a specific step of performing one or both of the derivation and the derivation of the position where the current outflow due to the interference of the stray current is occurring.
(8) The monitoring method according to one aspect of the present invention is the monitoring method according to (7) above, and a potential measuring machine for measuring the ground potential is attached to each of the floor slabs of the plurality of foundation structures. Is installed, and in the specific step, either the position of the floor slab in which the low ground contact object is in contact with the foundation portion is derived, or the position of the floor slab in which the current outflow occurs due to the interference of the stray current is derived. Do one or both.

(9) The monitoring method according to one aspect of the present invention is the monitoring method according to (6) above, and in the receiving step, an electric current is supplied to each foundation portion of the plurality of foundation structures. Information indicating the anticorrosion current generated by each of the plurality of anodes is received, and the monitoring method applies to the foundation portion based on the information indicating the anticorrosion current generated by each of the plurality of anodes received in the receiving step. It has a specific step of deriving the position where the low ground object is in contact and deriving the position where the current outflow occurs due to the interference of the stray current, or both.
(10) The monitoring method according to one aspect of the present invention is the monitoring method according to (9) above, and a current measuring machine for measuring the anticorrosion current is attached to each of the floor slabs of the plurality of foundation structures. Is installed, and in the specific step, either the position of the floor slab in which the low ground contact object is in contact with the foundation portion is derived, or the position of the floor slab in which the current outflow occurs due to the interference of the stray current is derived. Do one or both.

According to the embodiment of the present invention, when the steel foundation beam is electrically protected, the current due to the presence / absence of contact with other metals, the position, and the interference of the stray current, which is the cause of the foundation beam not reaching the corrosion protection potential. It is possible to specify whether or not an outflow has occurred and the location of the outflow.

It is a figure which shows the basic structure which concerns on embodiment of this invention. It is a figure which shows an example of the monitoring system which concerns on embodiment of this invention. It is a figure which shows an example of the foundation floor slab. It is a block diagram which shows the monitoring apparatus which comprises the monitoring system which concerns on embodiment of this invention. It is a figure which shows an example of the dimension of a foundation beam. It is a figure which shows an example of the installation position of a reference electrode. It is a figure which shows an example of the simulation result. It is a figure which shows an example of the simulation result. It is a figure which shows an example of the simulation result. It is a figure which shows an example of a metal contact position. It is a figure which shows an example of the simulation result. It is a figure which shows an example of the simulation result. It is a figure which shows an example of the foundation floor slab. It is a figure which shows an example of the installation position of a reference electrode. It is a figure which shows an example of the simulation result. It is a figure which shows an example of the simulation result. It is a figure which shows an example of the simulation result. It is a figure which shows an example of a metal contact position. It is a figure which shows an example of the simulation result. It is a figure which shows an example of the simulation result. It is a figure which shows an example of a steel foundation beam. It is a figure which shows an example of the time-dependent change of the magnesium alloy anode generation current at the time of contact with a metal object. It is a figure which shows an example of the time-dependent change of the generated current of the magnesium alloy anode at the outflow part of a stray current. It is a flowchart which shows an example of the operation of the monitoring system of this embodiment. It is a flowchart which shows an example of the operation of the monitoring system of this embodiment.

Next, the monitoring system and the monitoring method of the present embodiment will be described with reference to the drawings. The embodiments described below are merely examples, and the embodiments to which the present invention is applied are not limited to the following embodiments.
In all the drawings for explaining the embodiment, the same reference numerals are used for those having the same function, and the repeated description will be omitted.
Further, "based on XX" in the present application means "based on at least XX", and includes a case where it is based on another element in addition to XX. Further, "based on XX" is not limited to the case where XX is used directly, but also includes the case where XX is calculated or processed. "XX" is an arbitrary element (for example, arbitrary information).

(Embodiment)
(Basic structure)
FIG. 1 is a diagram showing a basic structure according to an embodiment of the present invention.
As shown in FIG. 1, the foundation structure 1 according to the present embodiment is installed on the ground G and a concrete pile 10 buried in the soil D and having a plurality of pile reinforcing bars 11 arranged inside. A concrete floor slab 20 in which a plurality of slab reinforcing bars 21 are arranged inside, and a steel foundation portion 30 which connects the pile 10 and the floor slab 20 and at least a part of which is buried in the soil D And a current supply unit 51 that supplies an anticorrosion current to the foundation unit 30. In the foundation structure 1, the electrocorrosion protection method is adopted.
In the following description, the direction in which the pile 10 extends is referred to as the vertical direction X, and the direction orthogonal to the vertical direction X is referred to as the horizontal direction.

The pile 10 has a tubular shape. A plurality of pile reinforcing bars 11 are arranged inside the peripheral wall of the pile 10. A plurality of pile reinforcing bars 11 are formed in a vertical direction X and a spiral shape at intervals in the circumferential direction.
The front and back surfaces of the floor slab 20 are formed in a plate shape facing the vertical direction X, and have a rectangular shape when viewed from above. A plurality of slab reinforcing bars 21 are arranged inside the floor slab 20 at intervals in the horizontal direction.

The foundation portion 30 includes a steel pile head joint portion 31 connected to the upper end portion of the pile 10, a steel strut portion 32 extending upward from the pile head joint portion 31, and a strut portion 32 in the horizontal direction. It extends and includes a steel foundation beam 33 that supports the floor slab 20.
The pile head joint 31 has a ridged tubular shape. A strut portion 32 is erected at the top of the pile head joint portion 31.
The pile head joint portion 31 is in contact with the pile reinforcing bar 11. As a result, the pile head joint portion 31 and the pile reinforcing bar 11 are electrically connected to each other. The upper end of the pile reinforcing bar 11 is in contact with the lower end opening edge of the pile head joint 31.

The strut portion 32 extends upward toward the ground G. The support columns 32 are arranged at the four corners of the floor slab 20 in the top view. In the illustrated example, H-steel having an H-shape when viewed from above is used as the support column 32, but a square steel pipe or the like is also used.
A plurality of foundation beams 33 are connected to the support columns 32. The foundation beam 33 is arranged at the peripheral edge of the floor slab 20 in a top view and has a rectangular shape, and supports the floor slab 20 from below.

The foundation beam 33 is an H-steel having an H-shape in a plan view when viewed from the extending direction. Of the foundation beams 33, flange portions 33B whose front and back surfaces face in the vertical direction X are separately connected to both ends of the web 33A whose front and back surfaces face orthogonal to the extending direction in the vertical direction X.
A stud gibber 34 projecting upward is provided on the upper surface of the flange portion 33B located on the upper side of the foundation beam 33. A plurality of stud gibber 34s are arranged on the upper surface of the flange portion 33B at intervals along the extending direction of the foundation beam 33. The foundation beam 33 is connected to the slab reinforcing bar 21 via a stud gibber 34. As a result, the foundation beam 33 and the slab reinforcing bar 21 are electrically connected to each other.

In the present embodiment, the foundation structure 1 is further provided with a first insulating member 40 that is interposed between at least one of the pile reinforcing bars 11 and the slab reinforcing bars 21 and the soil D and has a higher electric resistance than the soil D. There is. In the present embodiment, the first insulating member 40 is separately interposed between both the pile reinforcing bar 11 and the slab reinforcing bar 21 and the soil D. The first insulating member 40 includes a slab insulating member 41 interposed between the slab reinforcing bar 21 and the soil D, and a pile insulating member 42 interposed between the pile reinforcing bar 11 and the soil D. Not limited to such an embodiment, the first insulating member 40 may be interposed between either one of the pile reinforcing bar 11 and the slab reinforcing bar 21 and the soil D.
The first insulating member 40 is interposed between the pile 10 and the soil D, or between the floor slab 20 and the soil D. In the present embodiment, the slab insulating member 41 is interposed between the floor slab 20 and the soil D, and the pile insulating member 42 is interposed between the pile 10 and the soil D.

The slab insulating member 41 is formed of asphalt. The slab insulating member 41 is arranged above the split chestnut stone 22 laid on the ground G and below the floor slab 20. The slab insulating member 41 is interposed in the entire area on the lower surface of the floor slab 20. The slab insulating member 41 may be interposed in a part of the lower surface of the floor slab 20. As described above, the slab insulating member 41 is interposed between the floor slab 20 and the soil D, so that the first insulating member 40 is interposed between the slab reinforcing bar 21 and the soil D.
The slab insulating member 41 is not limited to asphalt. For example, any organic material having high insulating properties such as a polyethylene sheet and an insulating rubber sheet can be applied to the slab insulating member 41.

The pile insulating member 42 is painted on the outer peripheral surface of the pile 10. The pile insulating member 42 is painted on a portion located on the upper side of the outer peripheral surface of the pile 10. By coating the pile insulating member 42 on the outer peripheral surface of the pile 10 in this way, the pile insulating member 42 is interposed between the pile reinforcing bar 11 and the soil D.
The pile insulating member 42 is not limited to painting. For example, any organic material having high insulating properties such as asphalt, polyethylene sheet, and insulating rubber sheet can be applied to the pile insulating member 42.

Here, the dimension of the vertical direction X from the ground G to the lower end of the pile insulating member 42 is set to, for example, 5 m. In the soil D, in the portion located below 5 m from the ground G, the oxygen content (concentration) required for causing the cathode reaction described later becomes extremely small. Therefore, the pile insulating member 42 is not provided in the portion of the pile 10 located 5 m or less from the ground G. The length of the vertical direction X from the ground G to the lower end of the pile insulating member 42 may be 5 m or less, or 5 m or more. Further, the outer surface of the pile 10 may be painted with the pile insulating member 42 over the entire area in the vertical direction X.

In the foundation structure 1, the potential of the steel foundation portion 30 buried in the soil D (for example, based on the −0.6 V saturated copper sulfate electrode) is the reinforcing bar (pile reinforcing bar 11, slab reinforcing bar 11) arranged inside the concrete. It is lower than the potential of 21) (for example, based on -0.3 V saturated copper sulfate electrode). Therefore, the foundation portion 30 having a low potential serves as an anode, the pile reinforcing bar 11 and the slab reinforcing bar 21 having a high potential serve as a cathode, and a corrosion current is applied from the anode (foundation portion 30) to the cathode (pile reinforcing bar 11, slab reinforcing bar 21) through the soil D. Flow, CS macrocell corrosion is about to occur.
At this time, the anodic reaction shown in the following formula (1) occurs in the foundation portion 30, and the cathode reaction shown in the following formula (2) occurs in the pile reinforcing bar 11 and the slab reinforcing bar 21.

Fe → Fe ²⁺ + 2e ⁻・ ・ ・ (1)
1 / 2O ₂ + H ₂ O + 2e ⁻ → 2OH ⁻・ ・ ・ (2)

(Electrical protection)
The current supply unit 51 is a sacrificial anode 52. The sacrificial anode 52 is buried in soil D. The sacrificial anode 52 is conductive with the base portion 30. The potential of the magnesium alloy anode of the sacrificial anode 52 in soil D (for example, based on the -1.5V saturated copper sulfate electrode) is lower than the potential of the foundation 30 in soil D (for example, -0.6V). Therefore, based on this potential difference, the sacrificial anode 52 is used as the anode and the base portion 30 is used as the cathode, and the anticorrosion current flowing in the soil D can flow from the anode to the cathode. In the illustrated example, the sacrificial anode 52 is formed of a magnesium alloy or magnesium, and the sacrificial anode 52 causes the anode reaction shown in the following equation (3).
^{Mg → Mg 2+ + 2e - ···} (3)
As the material for forming the sacrificial anode 52, for example, zinc alloy or zinc can be used instead of magnesium alloy or magnesium.

According to the foundation structure 1 according to the present embodiment, the first insulating member 40 is interposed between at least one of the pile reinforcing bar 11 and the slab reinforcing bar 21 and the soil D. Therefore, among the pile reinforcing bars 11 and the slab reinforcing bars 21 (cathodes) arranged in the concrete, for example, in the portion located in the region where the oxygen concentration is high in the soil D, the cathode reaction represented by the above equation (2) Can be suppressed, and the flow of current from the soil D into the pile reinforcing bar 11 and the slab reinforcing bar 21 can be suppressed. As a result, the total amount of corrosion current can be suppressed and the corrosion current density at the anode (foundation portion 30) can be reduced, and CS macrocell corrosion at the foundation portion 30 can be suppressed.

Further, by interposing the first insulating member 40 between the pile 10 or the floor slab 20 and the soil D, the pile reinforcing bar 11 or the slab reinforcing bar 21 can be insulated from the soil D. This facilitates the work of insulating the pile reinforcing bars 11 or the slab reinforcing bars 21 as compared with a configuration in which the outer surfaces of the plurality of pile reinforcing bars 11 or the plurality of slab reinforcing bars 21 are individually covered with the first insulating member 40, for example. It can be carried out.

Further, according to the foundation structure 1 in the present embodiment, the current supply unit 51 supplies the anticorrosion current to the foundation unit 30. Therefore, the potential of the foundation portion 30 in the soil D that has been transferred to your side is, of course, general soil corrosion up to the natural potential of the foundation portion 30 when CS macrocell corrosion does not occur due to the anticorrosive current. It is possible to reduce the anticorrosion potential to the extent that microcell corrosion does not occur. In this way, the CS macrocell corrosion and the microcell corrosion of the base portion 30 can be suppressed by the electrocorrosion protection method.
The electrocorrosion protection needs to be designed so that the foundation portion 30 has a design service life and an corrosion protection potential. Specifically, the required anticorrosion is obtained by multiplying the anticorrosion current density (for example, 0.02 A / m ² ) required for the foundation 30 to reach the anticorrosion potential by the surface area of the foundation 30 to be electrocorroded. The current is calculated to determine the mass, shape, size, and number of sacrificial anodes 52 that can supply the anticorrosion current over its useful life.

Further, in the present embodiment, since the foundation portion 30, the pile reinforcing bar 11, and the slab reinforcing bar 21 are conductive, the anticorrosion current of the sacrificial anode 52 is not only the foundation portion 30, but also the insulating material of the pile reinforcing bar 11, the slab reinforcing bar 21. Anticorrosion current flows into the defective part.
Therefore, in the design of the sacrificial anode 52, the current flowing into the pile reinforcing bar 11 and the slab reinforcing bar 21 is added in addition to the foundation portion 30, and the mass, shape, size, and number of the sacrificial anode 52 are determined.

(Effect of contact with other metal objects under electrolytic protection)
The electrocorrosion protection determines the range in which the corrosion protection current flows, and is designed so that the corrosion protection target has the corrosion protection potential. When another metal object comes into contact with the metal part of the foundation structure 1 which is the object of corrosion protection, the anticorrosion current also flows into the other contact metal object, so that the inflow range of the anticorrosion current expands and it is originally the object of corrosion protection. The anticorrosion current density to flow into the steel base portion 30 decreases, and the base portion 30 does not reach the anticorrosion potential, becomes a potential on the noble side (higher) than the anticorrosion potential, and corrosion occurs.
Further, as for the anode-generated current, the sacrificial anode 52 closer to the position where the metal object is in contact has a larger anode-generated current, and the farther from the other metal-contacted metal object, the smaller the anode-generated current tends to be.

(Effect of interference due to stray current under electrolytic protection)
If the foundation structure 1 is present in the soil through which the stray current is flowing, a part of the stray current may flow into a part of the foundation structure 1 and flow out from another position of the foundation structure 1. In the basic structure 1 in which the stray current flows in, the ground potential is on the base side, and the anticorrosion effect can be obtained by this stray current, but in the basic structure 1 in which the stray current flows out, the ground potential shifts to your side and corrosion occurs. Occur.
On the other hand, the anode-generated current in the range where the stray current flows into the foundation structure 1 decreases, and conversely, the anode-generated current in the range where the stray current flows out into the foundation structure 1 increases. In particular, when the stray current flows out from the sacrificial anode 52, the sacrificial anode 52 is rapidly consumed due to the excessive current, and there is a risk that the sacrificial anode 52 will be consumed before reaching the planned useful life.

(Monitoring system)
FIG. 2 is a diagram showing an example of a monitoring system according to an embodiment of the present invention.
The monitoring system 200 detects that the steel foundation beam 33 of the foundation structure 1 does not reach the anticorrosion potential even though it is electrically protected. Further, the monitoring system 200 identifies the reason why the steel foundation beam 33 of the foundation structure 1 does not reach the anticorrosion potential. In the present embodiment, as an example, the case where it is detected that the steel foundation beam 33 of the foundation structure 1 does not reach the anticorrosion potential will be described for each foundation floor slab including the four foundation structures 1. However, the number of foundation structures 1 included in the foundation floor slab is not limited to four. For example, the foundation slab may contain 1 to 3 foundation structures 1 or 5 or more foundation structures 1.
The monitoring system 200 includes foundation beams of a plurality of foundation structures 1a-11, foundation structure 1b-11, foundation structure 1c-11, and foundation structure 1d-11 included in the foundation floor slab B11. Measure the ground potential. Here, the foundation floor slab is a member that directly receives a load.
The foundation portion 30 of the foundation structure 1a-11 and the foundation portion 30 of the foundation structure 1b-11 share a steel foundation beam 33ab-11. The foundation portion 30 of the foundation structure 1b-11 and the foundation portion 30 of the foundation structure 1d-11 share a steel foundation beam 33bd-11. The foundation portion 30 of the foundation structure 1d-11 and the foundation portion 30 of the foundation structure 1c-11 share a steel foundation beam 33dc-11. The foundation portion 30 of the foundation structure 1c-11 and the foundation portion 30 of the foundation structure 1a-11 share a steel foundation beam 33ca-11.
Hereinafter, any foundation beam among the foundation beam 33ab-mn, the foundation beam 33bc-mn, the foundation beam 33ca-mn, and the foundation beam 33bd-mn will be referred to as the foundation beam 33.

In the example shown in FIG. 2, in order to measure the ground potential of the foundation beam 33, the potential measuring machine 60a-11 uses the reference electrode 71a-11 and the steel foundation beam of the foundation portion 30 of the foundation structure 1a-11. It is connected to the coupon 72a-11 connected to 33 via an electric wire. A potential measuring machine for measuring the ground potential is installed on each floor slab of the plurality of foundation structures. The potential measuring device 60a-11 is connected to the monitoring device 100 via the network 50. Further, the steel foundation beam 33 of the foundation portion 30 of the foundation structure 1a-11 is connected via the switch SW-11.
The ground potential of the foundation beam 33 is based on the reference electrode 71a-11 of the coupon 72a-11 that simulates the exposed steel surface of the coating defect portion of the steel foundation beam 33 (hereinafter referred to as “coating defect portion”). Measure as the ground potential. The coupon is a small steel piece having the same composition as the steel foundation beam and having a surface area known in advance.

Since a zinc reference electrode is generally used as the reference electrode 71a-11 that can be buried in the soil and used permanently, a zinc reference electrode is applied for measuring the ground potential of a steel foundation beam. .. The zinc reference electrode shall have a zinc alloy covered with a backfill containing bentonite as the main component.
The reference electrode 71a-11 is installed close to the coupon 72a-11. The reason is that when there is a distance from the coupon 72a-11 to the reference electrode 71a-11, the voltage drop (IR drop) in the soil caused by the anticorrosion current flowing in the soil is relative to the ground potential of the coupon 72a-11. This is because it is added to the negative side, so even if the coupon 72a-11 does not reach the anticorrosion potential, it is determined that the coupon 72a-11 apparently reaches the anticorrosion potential.
Further, in addition to the method of bringing the reference electrode 71a-11 closer to the coupon 72a-11, the switch SW-11 cuts off the anticorrosion current flowing into the coupon 72a-11, and the ground potential with respect to the coupon 72a-11 at that moment. Is measured with the reference electrode 71a-11, the IR drop is further suppressed.
The ground potential of the coupon when the coupon is not turned off is called the coupon on potential, and the ground potential of the coupon when the coupon is turned off is called the coupon off potential.
A voltmeter, a high-sensitivity recorder, a digital multimeter, a data logger, and the like are used in the potential measuring machine 60a-11. The electric wire is usually connected to the potential measuring machine 60a-11 with the reference electrode 71a-11 as the negative electrode and the coupon 72a-11 as the positive electrode.
The potential measuring machine 60a-11 simulates the ground potential of the coating film defect of the steel foundation beam 33 of the foundation portion 30 with reference to the reference electrode 71a-11 and the coating film defect portion of the steel foundation beam 33. As the ground potential of the coupon 72-a11, information indicating the measurement result of the ground potential, identification information of the foundation beam 33, and ground potential measurement information including the measurement time information are created, and the ground potential measurement information is created. Is transmitted to the monitoring device 100.

Further, in order to measure the current generated in the current supply unit 51a-11, the current measuring machine 70a-11 uses the current supply unit 51a-11 and the steel foundation beam 33 of the foundation portion 30 of the foundation structure 1a-11. Is connected with. The current measuring device 70a-11 is connected to the monitoring device 100 via the network 50. The generated current of the current supply unit 51a-11 is measured by a current measuring machine 70a-11 inserted between the current supply unit 51a-11 and the steel foundation beam 33 of the foundation structure 1a-11. For the current measuring machine 70a-11, a combination of an ammeter, a shunt and a high-sensitivity recorder, a digital multimeter, and a data logger is used. When the magnitude of the generated current is larger than the design value, the design value is provided by a variable resistor or fixed resistor inserted in series with the current circuit on the assumption that the steel foundation beam 33 maintains the anticorrosion potential. Suppress the generated current so that it is within.
Since one or more current supply units 51a-11 are installed on one floor, anticorrosion monitoring for steel foundation beams is installed on each floor. A current measuring machine for measuring anticorrosion current is installed on each floor slab of multiple foundation structures. The reference electrode 71a-11 and the coupon 72a-11 are embedded close to the end far from the magnesium alloy anode where the anticorrosion current from the magnesium alloy anode is difficult to flow.
Further, the lead wires from the magnesium alloy anode, the reference electrode 71a-11, and the coupon 72a-11 are raised on the floor slab and connected to the terminal block provided on the building column. Protect the lead wire from the soil to the terminal block with a wire protection tube to prevent disconnection or damage. A switch and a resistor are arranged on the terminal block so that the anticorrosion current can be cut off and the current value can be adjusted. As a result, if you bring in a measuring instrument when you want to measure at all points, the ground potential (coupon-on potential and coupon-off potential) and anode of the steel foundation beam will be generated at the terminal block installed on the building column. It is possible to measure the magnesium alloy anode generation current, which is the anticorrosion current. In addition, continuous measurement is possible by installing a data logger as needed. Further, if the network 50 and the monitoring device 100 are added, remote monitoring becomes possible.
The current measuring machine 70a-11 measures the current generated from the current supply unit 51a-11 and flows into the foundation portion 30 including the foundation beam 33 and the pile reinforcing bar connected to the foundation portion 30, and the information showing the measurement result of the current and the foundation beam. Current measurement information including the identification information of 33 and the measurement time information is created, and the created current measurement information is transmitted to the monitoring device 100.

Further, the monitoring system 200 includes a foundation structure 1a-mn (m and n are integers of m> 1 and n> 1) included in the foundation floor slab Bmn, a foundation structure 1b-mn, and a foundation structure 1c-mn. , Of the foundation structure 1d-mn, the ground potentials of a plurality of foundation beams are measured.
FIG. 3 is a diagram showing an example of a foundation floor slab. As shown in FIG. 3, the foundation portion 30 of the foundation structure 1a-mn and the foundation portion 30 of the foundation structure 1b-mn share a steel foundation beam 33ab-mn. The foundation portion 30 of the foundation structure 1b-mn and the foundation portion 30 of the foundation structure 1d-mn share a steel foundation beam 33bd-mn. The foundation portion 30 of the foundation structure 1d-mn and the foundation portion 30 of the foundation structure 1c-mn share a steel foundation beam 33dc-mn. The foundation portion 30 of the foundation structure 1c-mn and the foundation portion 30 of the foundation structure 1a-mn share a steel foundation beam 33ca-11. Return to FIG. 2 and continue the explanation. In the example shown in FIG. 2, in order to measure the ground potential of the foundation beam 33, the potential measuring machine 60a-mn is a steel foundation beam of the collating electrode 71a-mn and the foundation portion 30 of the foundation structure 1a-mn. It is connected to a coupon 72a-mn connected to 33 (foundation beam 33ab-mn, foundation beam 33ca-mn) via an electric wire. The potential measuring device 60a-mn is connected to the monitoring device 100 via the network 50. Further, the steel foundation beam 33 (foundation beam 33ab-mn, foundation beam 33ca-mn) of the foundation portion 30 of the foundation structure 1a-mn and the coupon 72a-mn are connected via the switch SW-mn. ..

The potential measuring machine 60a-mn measures the potential of the coupon 72a-mn with respect to the soil with reference to the reference electrode 71a-mn, and includes information indicating the measurement result of the ground potential of the foundation beam 33 and identification information of the foundation beam 33. , The ground potential measurement information including the measurement time information is created, and the created ground potential measurement information is output to the monitoring device 100.
Further, in order to measure the current generated in the current supply unit 51a-mn, the current measuring machine 70a-mn uses the current supply unit 51a-mn and the steel foundation beam 33 of the foundation portion 30 of the foundation structure 1a-11. Is connected with. The current measuring machine 70a-mn is connected to the monitoring device 100 via the network 50.
The current measuring machine 70a-mn measures the current generated from the current supply unit 51a-mn and flows into the foundation portion 30 including the foundation beam 33 and the pile reinforcing bar connected to the foundation portion 30, and the information showing the measurement result of the current and the foundation. The ground potential measurement information including the identification information of the beam 33 and the measurement time information is created, and the created ground potential measurement information is output to the monitoring device 100.

The monitoring device 100 includes the potential measurement information to ground output by each of the potential measuring machines 60a-11 to 60a-mn and the current measurement information output by each of the current measuring machines 70a-11 to the current measuring machine 70a-mn. And receive. The monitoring device 100 determines whether or not a low grounded object is in contact with the steel foundation beam 33 of the foundation portion 30 based on the received ground potential measurement information and the current measurement information, and interferes with the stray current. Either or both of the determination as to whether or not the current outflow has occurred is performed.

Hereinafter, any of the foundation plate B11 to the foundation plate Bmn will be referred to as a foundation plate Bmn. Further, any foundation structure among the foundation structures 1a-11 to 1a-mn is described as the foundation structure 1a-mn, and any foundation structure among the foundation structures 1b-11 to the foundation structure 1b-mn is described as the foundation structure 1b. It is described as −mn, and any foundation structure among the foundation structures 1c-11 to 1c-mn is described as the foundation structure 1c-mn, and any foundation structure among the foundation structures 1d-11 to the foundation structure 1d-mn is described. Is described as the basic structure 1d-mn.
Further, any current supply unit among the current supply units 51a-11 to 51a-mn is described as a current supply unit 51a-mn, and any of the potential measuring machines 60a-11 to 60a-mn The potential measuring machine is referred to as a potential measuring machine 60a-mn. Further, any potential measuring machine 60a-11 to 60a-mn of the potential measuring machine is described as a potential measuring machine 60a-mn, and any of the current measuring machines 70a-11 to 70a-mn The current measuring machine is referred to as a current measuring machine 70a-mn. Further, any matching electrode among the matching electrodes 71a-11 to 71a-mn is referred to as the matching electrode 71a-mn. Further, any coupon among the coupons 72a-11 to 72a-mn is described as the coupon 72a-mn.

Hereinafter, the monitoring device 100 will be described among the potential measuring machine 60a-11 to the potential measuring machine 60a-mn, the current measuring machine 70a-11 to the current measuring machine 70a-mn, and the monitoring device 100 included in the monitoring system 200. To do.
(Monitoring device 100)
FIG. 4 is a block diagram showing a monitoring device constituting the monitoring system according to the embodiment of the present invention.
The monitoring device 100 is realized by a device such as a personal computer, a server, or an industrial computer.
The monitoring device 100 includes a communication unit 110, a storage unit 120, an information processing unit 130, and a bus line such as an address bus or a data bus for electrically connecting each component as shown in FIG. It is equipped with 160.

The communication unit 110 is realized by a communication module. The communication unit 110 communicates with an external device such as the potential measuring machine 60a-11 to the potential measuring machine 60a-mn and the current measuring machine 70a-11 to the current measuring machine 70a-mn via the network 50. Specifically, the communication unit 110 receives the ground potential measurement information transmitted by each of the potential measuring machines 60a-11 to the potential measuring machine 60a-mn, and outputs the received ground potential measurement information to the information processing unit 130. .. Further, the communication unit 110 receives the current measurement information transmitted by each of the current measuring machines 70a-11 to the current measuring machine 70a-mn, and outputs the received current measurement information to the information processing unit 130.

The storage unit 120 is realized by, for example, a RAM (Random Access Memory), a ROM (Read Only Memory), an HDD (Hard Disk Drive), a flash memory, or a hybrid storage device in which a plurality of these is combined. A part or all of the storage unit 120 can be accessed via the network 50 by a processor of the monitoring device 100 such as NAS (Network Attached Storage) or an external storage server instead of being provided as a part of the monitoring system 200. It may be realized by an external device. The storage unit 120 stores the program 122 executed by the information processing unit 130, the application 124, the simulation result 126, and the foundation beam position information 128.

The application 124 causes the monitoring device 100 to receive the ground potential measurement information transmitted by each of the potential measuring devices 60a-11 to 60a-mn.
The application 124 causes the monitoring device 100 to receive the current measurement information transmitted by each of the current measuring machines 70a-11 to the current measuring machine 70a-mn.
The application 124 causes the monitoring device 100 to receive a plurality of received ground potential measurement information and a plurality of current measurement information.
Based on the plurality of ground potential measurement information received by the monitoring device 100 and the plurality of current measurement information, the application 124 has other metal objects (low grounding) on all the steel materials conducting with the steel foundation beam 33. Have them judge whether or not there is a place where the object) is in contact.
The application 124 causes the monitoring device 100 to identify a portion where another metal object is in contact with all the steel materials conducting with the steel foundation beam 33.
The application 124 causes the monitoring device 100 to determine whether or not a current outflow occurs due to the interference of the stray current from the electric railway or the like based on the received ground potential measurement information and the current measurement information.
The application 124 causes the monitoring device 100 to specify the location when it is determined that a current outflow due to interference of a stray current from an electric railway or the like has occurred.

The simulation result 126 shows the simulation results in the case where all the steel materials conducting with the steel foundation beam have no contact with other metal objects (low grounding objects) and the stray current from the electric railway or the like. The simulation results of the case where the current outflow due to the interference does not occur and the case where the current outflow occurs due to the interference are stored. Here, as an example of the simulation result in the case where there is no place where other metal objects are in contact with all the steel materials conducting with the steel foundation beam, the electrolytic corrosion protection is applied to the steel foundation beam. This is the result of simulating the potential using a plurality of reference electrodes when the application is applied. The details will be described later. An example of the simulation results of the case where the current outflow due to the interference of the stray current from the electric railway etc. does not occur and the case where the current outflow occurs due to the interference is the case where the electric corrosion protection by the sacrificial anode (magnesium alloy) is applied. , This is the result of simulating the potential measurement value by changing the direction of the stray current. The details will be described later.
The foundation beam position information 128 is table-type information in which the identification information of the foundation beam and the position information of the foundation beam are associated with each other.

The information processing unit 130 is, for example, a functional unit (hereinafter referred to as “software functional unit”) realized by executing a program 122 stored in a storage unit 120 or an application 124 by a processor such as a CPU (Central Processing Unit). Is. All or part of the information processing unit 130 may be realized by hardware such as LSI (Large Scale Integration), ASIC (Application Specific Integrated Circuit), or FPGA (Field-Programmable Gate Array), and is a software function. It may be realized by a combination of a unit and hardware.
The information processing unit 130 includes, for example, a reception unit 131, a processing unit 132, and a specific unit 133.

The reception unit 131 acquires a plurality of ground potential measurement information output by the communication unit 110, and receives the acquired plurality of ground potential measurement information. Further, the reception unit 131 acquires a plurality of current measurement information output by the communication unit 110, and receives the acquired plurality of current measurement information. The reception unit 131 outputs the received plurality of ground potential measurement information and the plurality of current measurement information to the processing unit 132.
The processing unit 132 acquires a plurality of ground potential measurement information output by the reception unit 131 and a plurality of current measurement information, and is made of steel based on the acquired plurality of ground potential measurement information and the current measurement information. It is determined whether or not other metal objects are in contact with all the steel materials conducting with the foundation beam 33, and whether or not a current outflow occurs due to the interference of the stray current from the electric iron or the like.
The ground potential of the steel foundation beam 33 is linked to the fluctuation of the current generated at the anode. Therefore, the phenomenon can be more reliably captured based on the ground potential and the current generated at the anode. The ground resistance R of the object can be derived based on the fluctuation amount of the ground potential and the fluctuation of the current generated at the anode. Since the ground resistance R is a function of the soil resistivity ρ and the damaged area A, it can be used as a guide for the size of the contact object. In addition, the current outflow due to the interference of the stray current also has a high correlation between the ground potential and the current generated at the anode.
Therefore, in the present embodiment, the case of measuring the ground potential and the current generated at the anode will be described. The current generated at the anode also affects the amount of wear of the anode, so it is also used to check the useful life.
Specifically, when another metal object is in contact with all the steel materials conducting with the steel foundation beam 33, the current supply unit 51 supplies the steel foundation beam 33 of the foundation portion 30 with anticorrosion. The current increases sharply, and the ground potential of the steel foundation beam 33 becomes noble. The rapid increase in the anticorrosion current and the nobility of the ground potential are remarkable at the contact point, and the farther away from the contact point, the less the increase in the anticorrosion current and the nobility of the ground potential are observed.

On the other hand, in the interference of stray current, a place where the stray current flows into any one of the steel foundation part, the pile reinforcing bar 11, the current supply part 51, or a combination thereof (hereinafter referred to as "stray current inflow point"). ), And a portion where the stray current flows out from any one of the steel foundation portion, the pile reinforcing bar 11, the current supply portion 51, or a combination thereof (hereinafter referred to as “stray current outflow portion”). The stray current inflow point and the stray current outflow point are separated. At the stray current inflow point, the ground potential of the steel foundation beam 33 is lowered, and the anode generated current is reduced. At the stray current outflow point, the ground potential of the steel foundation beam 33 becomes noble and the anode generated current increases.
The processing unit 132 acquires information indicating the ground potential measurement result included in each of the acquired plurality of ground potential measurement information, and based on each of the acquired information indicating the ground potential measurement result, the ground potential It is determined whether or not the measurement result of is changed by the potential threshold value or more.
When none of the measurement results of the plurality of potentials changes by the potential threshold value or more, the processing unit 132 means that no other metal object is in contact with all the steel materials conducting with the steel foundation beam 33, and the stray current is generated. It is determined that no current outflow due to interference has occurred.
When at least one of the measurement results of the plurality of potentials changes by the potential threshold value or more, the processing unit 132 determines whether or not the measurement results of the plurality of potentials have changed on the base side.
When the measurement results of the plurality of potentials do not fluctuate on the base side, the processing unit 132 determines that the steel material conducting with the steel foundation beam 33 is in contact with another metal object.
When at least one of the measurement results of the plurality of potentials fluctuates to the base side, the processing unit 132 determines that a current outflow due to interference of the stray current has occurred.
Further, the processing unit 132 acquires information indicating the current measurement result included in each of the acquired plurality of current measurement information, and the current measurement result is obtained based on the information indicating the acquired current measurement result. Determine if the change is greater than or equal to the current threshold.
When none of the measurement results of the plurality of currents changes by the current threshold value or more, the processing unit 132 means that no other metal object is in contact with all the steel materials conducting with the steel foundation beam 33, and the stray current is generated. It is determined that no current outflow due to interference has occurred.
When at least one of the measurement results of the plurality of currents changes by the current threshold value or more, the processing unit 132 determines whether or not there is any decrease in the measurement results of the plurality of currents.
If there is no decrease in the measurement results of the plurality of currents, the processing unit 132 determines that the steel material conducting with the steel foundation beam 33 is in contact with another metal object.
When the measurement results of the plurality of currents are reduced, the processing unit 132 determines that a current outflow occurs due to the interference of the stray current.

The processing unit 132 displays information indicating that contact with a low grounded object has occurred when it is determined that the steel material conducting with the steel foundation beam 33 is in contact with another metal object. Output to unit 150. When the processing unit 132 determines that contact with a low grounded object has occurred, information indicating that contact with a low grounded object has occurred, identification information of a plurality of steel foundation beams 33, and steel thereof. The low-grounded object contact generation information including the information associated with the information indicating the measurement result of the potential measured by the foundation beam 33 manufactured by the steel is created, and the created low-grounded object contact generation information is output to the specific unit 133.
When it is determined that a current outflow has occurred due to the interference of the stray current, the processing unit 132 outputs information indicating that the current outflow has occurred due to the interference of the stray current to the display unit 150. When the processing unit 132 determines that a current outflow has occurred due to the interference of the stray current, the processing unit 132 includes information indicating that the current outflow has occurred due to the interference of the stray current, identification information of the plurality of steel foundation beams 33, and information. Stray current generation information including information indicating the measurement result of the potential measured by the steel foundation beam 33 and information associated with the information is created, and the created stray current generation information is output to the specific unit 133.

When one or both of the low ground contact occurrence information output by the processing unit 132 and the stray current generation information are acquired, the specific unit 133 acquires the low ground contact occurrence information and the stray current generation information. Based on either one or both of the above, the simulation result 126 stored in the storage unit 120, and the foundation beam position information 128, either the contact point with the low ground object or the stray current generation point. Identify one or both.
Here, the details of the simulation result 126 stored in the storage unit 120 will be described.
The simulation conditions (numerical analysis conditions) will be described. One section surrounded by girders was used as the foundation floor slab Bmn. The target of corrosion protection was a steel foundation beam, and the corrosion protection method was electrocorrosion protection using a sacrificial anode (magnesium alloy). The foundation beams are painted. The sacrificial anode had a size Φ of 200 mm × 1200 mm and was buried horizontally at a depth of 1.6 m from the ground. The polarization curve of the beam was set to 1% of the insulation defect rate of the coating, and the defect rate was applied to the polarization curve of the unpainted steel material (in the soil). The soil resistance was 50 Ωm.
Regarding the stray current, the potential gradient was set to 5 mV / m. The direction of the stray current was changed, and the direction was derived from the measured value of the potential.
For other metal contacts, steel contacts were assumed. The steel in contact has a size Φ of 100 mm × 2000 mm. The contact position was calculated from the potential measurement value by changing the contact position.
Regarding the steel foundation beam 33, the longitudinal length of the foundation beam 33ab-mn, the longitudinal length of the foundation beam 33bd-mn, and the longitudinal length of the foundation beam 33dc-mn described with reference to FIG. 3 Each of the length of the foundation beam 33ca-mn in the longitudinal direction was set to 10 m.
FIG. 5 shows an example of the dimensions of the foundation beam. As shown in FIG. 5, the flange thickness was 28 mm, the web thickness was 16 mm, the height was 900 mm, and the length of the short side of the flange was 250 mm.

(Example of simulation result (1))
FIG. 6 shows an example of the installation position of the reference electrode. As shown in FIG. 6, the distance between the reference electrode 2E installed in the foundation structure 1a-mn and the reference electrode 1E installed in the foundation structure 1b-mn was set to 9 m. Further, the distance between the reference electrode 1E installed in the foundation structure 1b-mn and the reference electrode 4E installed in the foundation structure 1d-mn was set to 9 m. Further, the distance between the reference electrode 4E installed in the foundation structure 1d-mn and the reference electrode 3E installed in the foundation structure 1c-mn was set to 9 m. Further, the distance between the reference electrode 3E installed in the foundation structure 1c-mn and the reference electrode 2E installed in the foundation structure 1a-mn was set to 9 m. The reference electrode 1E, the reference electrode 2E, the reference electrode 3E, and the reference electrode 4E were installed at a depth of 0.9 m from the ground.

FIG. 7 is a diagram showing an example of simulation results. FIG. 7 shows a case where the current outflow due to the interference of the stray current does not occur and the metal is not in contact with the foundation beam.
The upper view of FIG. 7 shows the potentials of the foundation beam 33ab-mn, the foundation beam 33bd-mn, the foundation beam 33dc-mn, the foundation beam 33ca-mn, and the current supply unit 51, respectively. The lower figure (a) of FIG. 7 shows a potential at a depth of 0.9 m from the ground. In both the upper figure (a) and the lower figure (b) of FIG. 7, the anticorrosion potential is −0.725 V vs SSE.
According to the upper figure (a) of FIG. 7, since the surface of the foundation beam is −0.875V vs SSE, it can be seen that it is polarized in a base manner. According to the lower figure (b) of FIG. 7, since the current supply unit 51 is -1,000 V vs SSE, it can be seen that the current supply unit 51 is basely polarized.

FIG. 8 is a diagram showing an example of simulation results. FIG. 8 shows the relationship between the direction of the stray current and the potential distribution. The direction of the stray current will be described. The center of the foundation plate bridge Bmn is the origin, and the horizontal line drawn to the right from the origin is 0 degrees. The direction of rotation counterclockwise with respect to this horizontal line is the positive direction.
In FIG. 8, (a) is a case where there is no stray current, (b) is a case where the stray current flows in from the direction of 0 degrees, and (c) is a case where the stray current flows in from the direction of 15 degrees. Yes, (d) is a case where the stray current flows in from the direction of 30 degrees, and (e) is a case where the stray current flows in from the direction of 45 degrees. In FIG. 8, the anticorrosion potential is −0.725 V vs SSE. According to FIG. 8, it can be seen that the direction in which the stray current flows is negatively polarized by changing the direction in which the stray current flows.

FIG. 9 is a diagram showing an example of simulation results.
FIG. 9 shows, for each of the reference electrodes 1E to 4E described with reference to FIG. 6, when there is no stray current, when the direction in which the stray current flows is 0 degrees, and in the direction in which the stray current flows. The result of deriving the potential is shown in the case where the temperature is 15 degrees, the direction in which the stray current flows in is 30 degrees, and the direction in which the stray current flows in is 45 degrees. According to FIG. 9, since the reference electrode 1E and the reference electrode 4E are closer to the direction in which the stray current flows, as compared with the reference electrode 2E and the reference electrode 3E, it can be seen that they are changed to the base side.
Further, based on FIG. 9, the magnitude and direction (angle) of the potential gradient were derived from the potential value of the reference electrode. The results are shown in Table 1.

According to Table 1, it can be seen that the angle of the potential gradient derived from the potential value of the reference electrode and the direction of the stray current are substantially the same. Therefore, it can be seen that the direction of the stray current can be derived from the measured value of the potential of the reference electrode.

(Example of simulation result (Part 2))
FIG. 10 shows an example of the metal contact position. The reference electrode 1E to the reference electrode 4E were installed at a depth of 0.9 m from the ground as described above. The size Φ of the contact metal is 100 mm × 2000 mm.
In FIG. 10, as shown in (a), the contact metal (steel) CM was embedded at a depth of 0.45 m from the ground on the perpendicular bisector of the reference electrode 1E and the reference electrode 4E. As shown in (b), the contact metal (steel) CM was embedded at a position translated by 2 m in the + y direction with respect to (a). As shown in (c), the contact metal (steel) CM was embedded at a position translated by 4 m in the + y direction with respect to (a).

FIG. 11 is a diagram showing an example of simulation results. FIG. 11 shows a case where there is no metal contact, a case (a) in FIG. 10, a case (b) in FIG. 10, and a case (c) in FIG. According to FIG. 11, it can be seen that the ground potential is noble when the metal is brought into contact with the metal as compared with the case where there is no metal contact.
FIG. 12 is a diagram showing an example of simulation results. FIG. 12 shows the analysis results when the metals are brought into contact with each other. 12 shows a case where there is no metal contact, a case of FIG. 10A, and a case of FIG. 10B for each of the reference electrode 1E to the reference electrode 4E described with reference to FIG. , The result of deriving the potential with respect to the case of (c) of FIG. 10 is shown. According to FIG. 12, it can be seen that the foundation beam can be changed to your side by bringing the metal into contact with each other. Further, according to FIG. 12, since the reference electrode 1E and the reference electrode 4E are closer to the contact metal than the reference electrode 2E and the reference electrode 3E, it can be seen that they are changed to the noble side.
Further, based on FIG. 12, the direction of the potential gradient is derived from the value of the reference electrode, and the position (contact estimated position) when the direction of the potential derived from the center of the beam is viewed, that is, the position in the y direction is determined. Derived. The results are shown in Table 2.

According to Table 2, it can be seen that the estimated contact position of the metal derived from the value of the reference electrode is close to the position where the metal is brought into contact. Therefore, it can be seen from the potential measurement value of the reference electrode that the contact position of the metal can be derived.

(Example of simulation result (3))
FIG. 13 is a diagram showing an example of a foundation floor slab.
An example of the simulation result (No. 3) is a unit obtained by collecting 3 × 6 sections of the above-mentioned example of the simulation result (No. 1 and No. 2) and one section of the steel foundation beam (foundation plate bridge B11). It is different in that. The sacrificial anode was buried horizontally in the center of each section and at a depth of 1.6 m from the ground.
FIG. 14 shows an example of the installation position of the reference electrode. As shown in FIG. 14, one section of the steel foundation beam (foundation floor slab B11) is collected in 3 × 6 sections, and the reference electrode 1E is provided at a total of 6 points, the four corners and the midpoint in the longitudinal direction. ~ Reference electrode 6E was installed.
FIG. 15 is a diagram showing an example of simulation results. FIG. 15 shows a case where no current outflow occurs due to the interference of the stray current and the low grounded object is not in contact with the foundation beam.
The upper figure (a) of FIG. 15 shows the potentials of each foundation beam and the current supply unit 51 for a group of 3 × 6 sections of a steel foundation beam. The lower figure (b) of FIG. 15 shows a potential at a depth of 0.9 m from the ground. In both the upper figure (a) and the lower figure (b) of FIG. 15, the anticorrosion potential is −0.725 V vs SSE.
According to the upper figure (a) of FIG. 15, since the surface of the foundation beam is −0.925 Vvs SSE, it can be seen that it is basely polarized. According to the lower figure (b) of FIG. 15, since the current supply unit 51 is -1,000 V vs SSE, it can be seen that the current supply unit 51 is basely polarized. Here, the 3 × 6 compartment is shown, but the same applies not only to the 3 × 6 compartment but also to any compartment.

FIG. 16 is a diagram showing an example of simulation results. FIG. 16 shows the relationship between the direction of the stray current and the potential distribution. For a group of 3 x 6 sections of a steel foundation beam, the center is the origin, and the horizontal line drawn to the right from the origin is 0 degrees. The direction of rotation counterclockwise with respect to this horizontal line is the positive direction.
In FIG. 16, (a) is a case where a current outflow does not occur due to interference of a stray current, (b) is a case where a stray current flows in from a direction of 0 degrees, and (c) is a case where a stray current is 45. This is the case where the stray current flows in from the direction of 90 degrees, and (d) is the case where the stray current flows in from the direction of 90 degrees. In FIG. 16, the anticorrosion potential is −0.750 V vs SSE. According to FIG. 16, it can be seen that the direction in which the stray current flows is negatively polarized by changing the direction in which the stray current flows. Here, the 3 × 6 compartment is shown, but the same applies not only to the 3 × 6 compartment but also to any compartment.
FIG. 17 is a diagram showing an example of simulation results. FIG. 17 shows the analysis result of the stray current. FIG. 17 shows a case where no current outflow occurs due to the interference of the stray current and a case where the direction in which the stray current flows is 0 degrees for each of the reference electrodes 1E to 6E described with reference to FIG. The results of deriving the potentials are shown for the case where the direction in which the stray current flows in is 45 degrees and the case where the direction in which the stray current flows in is 90 degrees. According to FIG. 17, as the direction in which the stray current flows in changes from 0 degrees to 90 degrees, the reference electrode 5E, the reference electrode 6E, and the reference electrode 3E, which are close to the direction in which the stray current flows in, change to the base side in order. You can see that it is doing.
Further, based on FIG. 17, the magnitude and angle of the potential gradient were derived from the value of the reference electrode. The results are shown in Table 3.

According to Table 3, it can be seen that the angle derived from the value of the reference electrode is close to the angle at which the stray current flows in. Therefore, it can be seen that the direction (angle) in which the stray current flows can be derived from the measured value of the potential of the reference electrode. That is, the position of the floor slab where the current outflow due to the interference of the stray current is generated can be derived.

(Example of simulation result (4))
FIG. 18 shows an example of the metal contact position. The reference electrode 1E to the reference electrode 6E were installed at a depth of 0.9 m from the ground as described above. The size Φ of the contact metal CM is 100 mm × 2000 mm.
In FIG. 18, the reference electrode 6E and the reference electrode 4E were translated by 4 m in the y-axis direction from the perpendicular bisector, and the contact metal (steel) CM was embedded at a depth of 0.45 m from the ground.
FIG. 19 is a diagram showing an example of simulation results. FIG. 19 shows a case where there is no metal contact and a case where there is no metal contact. According to FIG. 19, it can be seen that the ground potential is noble when the metal is brought into contact with the metal as compared with the case where there is no metal contact.
FIG. 20 is a diagram showing an example of simulation results. FIG. 20 shows the analysis result when the metal is brought into contact with the metal. FIG. 20 shows the potentials of each of the reference electrode 1E to the reference electrode 6E described with reference to FIG. 14 when there is no metal contact and when there is metal contact. According to FIG. 20, it can be seen that the foundation beam can be changed to your side by bringing the metal into contact with each other.
Further, based on FIG. 20, the direction of the potential gradient was derived from the value of the reference electrode, and the position when the direction of the potential derived from the center of the beam was viewed, that is, the position in the y direction was derived. The result was 1.2 m, which was close to the estimated contact position of the metal derived from the potential value of the reference electrode. Therefore, it can be seen from the measured value of the potential of the reference electrode that the contact position of the metal can be derived. That is, the position of the floor slab in which the low ground contact object is in contact with the foundation can be derived.

The explanation will be continued by returning to FIG. The specific unit 133 associates the identification information of the plurality of steel foundation beams 33 included in the acquired low ground contact occurrence information with the information indicating the measurement result of the potential measured by the steel foundation beam 33. Get the information. Based on each of the acquired identification information of the plurality of steel foundation beams 33, the specific portion 133 is associated with the identification information of each steel foundation beam 33 from the foundation beam position information 128 of the storage unit 120. Get the location information of. The specific unit 133 derives the position of the floor slab in contact with the low ground contact object based on each of the acquired position information of the plurality of foundation beams and the measurement result of the ground potential measured by the foundation beam. .. In addition, the specific unit 133 compares each of the acquired position information of the plurality of foundation beams with the measurement result of the ground potential measured by the foundation beam with the simulation result, and thereby, the position where the low ground contact object comes into contact. Is derived. Specifically, the specific unit 133 determines that there is no contact by comparing FIG. 12 with each of the acquired position information of the plurality of foundation beams and the measurement result of the ground potential measured by the foundation beam. Among case1, case2, and case3, the floor slab in which the most similar potential is obtained is selected, and the position where the ground contact object is in contact is derived from the selected floor slab.
In addition, the specific unit 133 is based on each of the acquired position information of the plurality of foundation beams and the measurement result of the ground potential measured by the foundation beam, each of the position information of at least three foundation beams and the foundation thereof. Obtain the measurement result of the ground potential measured by the beam. The specific unit 133 derives a potential gradient based on each of the acquired position information of the foundation beam at at least three locations and the measurement result of the ground potential measured by the foundation beam, and the direction from the derived potential gradient. Is derived. Based on the derived potential gradient, the specific unit 133 derives the position of the foundation beam when the direction of the potential gradient is viewed from the center of the foundation floor slab Bmn, thereby deriving the position where the low ground object is in contact. .. The identification unit 133 outputs information indicating the position where the derived low ground object comes into contact with the display unit 150 to the display unit 150.

Further, the specific unit 133 associates the identification information of the plurality of steel foundation beams 33 included in the acquired stray current generation information with the information indicating the measurement result of the potential measured by the steel foundation beam 33. Get the information. Based on each of the acquired identification information of the plurality of steel foundation beams 33, the specific portion 133 is associated with the identification information of each steel foundation beam 33 from the foundation beam position information 128 of the storage unit 120. Get the location information of. Based on each of the acquired position information of the plurality of foundation beams and the measurement result of the potential measured by the foundation beam, the specific unit 133 determines the position of the floor slab in which the current outflow due to the interference of the stray current is generated. Derived. Further, the specific unit 133 derives the direction of the stray current by comparing each of the acquired position information of the plurality of foundation beams with the measurement result of the potential measured by the foundation beam with the simulation result. Specifically, the specific unit 133 determines that there is no stray current by comparing FIG. 9 with each of the acquired position information of the plurality of foundation beams and the measurement result of the ground potential measured by the foundation beam. , 0 degree, 15 degree, 30 degree, and 45 degree, the floor slab in which the most similar potential is obtained is selected, and the direction of the stray current is derived from the selected floor slab.
In addition, the specific unit 133 is based on each of the acquired position information of the plurality of foundation beams and the measurement result of the ground potential measured by the foundation beam, each of the position information of at least three foundation beams and the foundation thereof. Obtain the measurement result of the ground potential measured by the beam. The specific unit 133 derives a potential gradient based on each of the acquired position information of the foundation beam at at least three locations and the measurement result of the ground potential measured by the foundation beam, and derives the potential gradient from the derived potential gradient. Derive that direction. The identification unit 133 derives the angle of the stray current from the center of the base slab Bmn based on the derived potential gradient by deriving the angle when the direction of the potential gradient is viewed. The identification unit 133 outputs information indicating the position where the derived stray current has flowed into the display unit 150.

Here, a process for detecting a metal contact portion due to the magnesium alloy anode generated current and a current outflow portion due to interference of the stray current will be described.
FIG. 21 is a diagram showing an example of a steel foundation beam.
The process of detecting the contact position of a metal object by the specific unit 133 will be described. In order to measure the generated current of the magnetesium alloy anode, a current measuring device is inserted between the magnesium alloy anode, the steel foundation beam and the conductive building column, and the current measuring device is prepared for each section of the steel foundation beam. To do. A current measuring device for measuring anticorrosion current is installed in each floor slab of the plurality of foundation structures. With this configuration, the magnesium alloy anode generated current in all compartments can be constantly monitored. As shown in FIG. 21, the positions of the steel foundation beams are set in the first row, the second row, ..., The nth row (n is an integer of n> 0) in the horizontal direction of the section, and the vertical direction of the section is set. The directions are the 1st row, the 2nd row, ..., The mth row (m is an integer of m> 0), and each position of the steel foundation beam is represented by the nth column × mth row. As an example, FIG. 21 shows 15 sections of 5 columns × 3 rows. In this case, a current measuring device is installed on the floor slab included in each of the 15 compartments.
If another metal object comes into contact with the steel foundation beam of 1 column × 1 row, the generated current of the magnesium alloy anode changes with the elapsed time.

FIG. 22 is a diagram showing an example of a change with time of the magnesium alloy anode generated current at the time of contact with a metal object.
When there is no contact with metal objects, the anticorrosion current is assumed to be almost constant regardless of the position of the steel foundation beam. When a metal object comes into contact with the steel foundation beam in this steady state, the current generated from the magnesium alloy anode also flows into the contacted metal contact portion. Therefore, the generated current of the magnesium alloy anode greatly increases from the steady state when a metal object comes into contact with it. The degree of increase in the generated current of the magnesium alloy anode is larger for the magnesium alloy anode closer to the metal contact portion with the steel foundation beam, and smaller for the magnesium alloy anode farther from the metal contact portion.
Therefore, the magnitude of the generated current of the magnesium alloy when the metal object comes into contact with the central portion of the steel foundation beam in the third row and the second row is generated in the steel foundation beam in the nth column × m row. When the current to be generated is expressed by "In, m", it is as follows.
I3,2> I3,1, I3,3, I2,2, I4,2> I2,1, I4,1, I2,3,I4,3
Therefore, if the generated current of the magnesium alloy anode can be constantly monitored, the contact position of the metal object can be estimated from the magnitude of the generated current of the magnesium alloy anode. The specific portion 133 derives a floor slab in which a low ground contact object is in contact with the base portion based on the magnitude of the generated current of the magnesium alloy anode.
The generated current of the magnesium alloy anode does not have to be constantly monitored by the communication line, and even by measuring the generated current of the magnesium alloy anode on a regular basis, the contact point of the metal object is determined by the magnitude of the generated current of the magnesium alloy anode. Can be estimated.
Further, the generated current of the magnesium alloy anode can be roughly measured at the contact points of metal objects even if the measurement is performed by skipping several adjacent magnesium alloy anodes instead of measuring at all points.

Next, the process in which the specific unit 133 detects the current outflow range due to the interference of the stray current will be described.
If there are several steel foundation beams where the stray current leaked from the rail is flowing in the soil from a DC electric railway, etc., the stray current flowing in the soil will have the least voltage drop. Therefore, it flows into a pile reinforcing bar having a low ground resistance, a coating defect part of a steel foundation beam, a magnesium alloy anode, or the like. The stray voltage that once flowed into the coating defect part of the pile reinforcing bar or steel foundation beam or the magnesium alloy anode flows out into the soil from the coating defect part of the pile reinforcing bar or steel foundation beam or the magnesium alloy anode in another place. Then, return to the rail of the DC electric railway.
FIG. 23 is a diagram showing an example of the time-dependent change of the generated current of the magnesium alloy anode at the outflow point of the stray current.
The stray current leaked from the DC electric rail is applied to the coating defect part of the steel foundation beam, the pile reinforcing bar, and the magnesium alloy anode in 1 row 1 row to 1 row 3 rows of the steel foundation beam shown in FIG. Consider the case where the inflow flows in, flows out from 1 row in 5 columns to 3 rows in 5 columns, and returns to the rail of the DC electric railway. In the 1st row 1st row to 1st row 3rd row where the stray current flows, the potential of the coating defect part of the steel foundation beam, the pile reinforcing bar, and the magnesium alloy anode shifts to the base side, and the generated current of the magnesium alloy anode is It decreases compared to before the stray current flows in.
On the other hand, when the stray current flows out from the coating defect part of the pile reinforcing bar or the steel foundation beam or the magnesium alloy anode, the coating defect of the pile reinforcing bar or the steel foundation beam occurs in the 5th column, 1st row to the 5th row, 3rd row. As the potential of the part and the magnesium alloy anode becomes noble, the generated current of the magnesium alloy anode increases as compared with before the stray current flows out. Corrosion occurs at the coating defects of pile reinforcing bars and steel foundation beams where stray current flows into the soil, and at the anode of magnesium alloy. In the magnesium alloy anode, the anode is forcibly dissolved, so that the anode life is shortened.
The current outflow range due to the interference of the stray current is where the generated current of the magnesium alloy anode rises. The identification unit 133 derives the position of the floor slab in which the current outflow due to the interference of the stray current is generated based on the generated current of the magnesium alloy anode. The explanation will be continued by returning to FIG.

The operation unit 140 is an input device that accepts user operations, and includes a pointing device such as a touch panel, buttons, dials, touch sensors, touch pads, and the like.
The display unit 150 is composed of, for example, a liquid crystal display or the like. The display unit 150 contains information output by the processing unit 132 indicating that the low ground object is in contact, information indicating the position where the low ground object output by the specific unit 133 is in contact, and stray current output by the processing unit 132. Information indicating that the current is occurring, information indicating the position where the stray current output by the specific unit 133 is generated, and the like are displayed.

(Operation of monitoring system)
24 and 25 are flowcharts showing an example of the operation of the monitoring system of the present embodiment. 24 and 25 mainly show the operation of the monitoring device 100 included in the monitoring system 200.
The ground potential fluctuates as the current flows in and out of the object. The fluctuation of the current changes immediately when the deformation occurs, but the ground potential is often accompanied by the polarization of the object, and the potential fluctuation due to the occurrence of the deformation is slower than the current. From the above, in the present embodiment, in addition to the steel member ground potential, both the anode generated current is monitored, and the presence or absence of contact with other metals and the presence or absence of stray current interference (outflow area is a corroded part) are detected. Continue the explanation of the case.
With reference to FIG. 24, the ground potential of the coupon 72a-11 connected to the steel foundation beam 33 of the foundation portion 30 of the foundation structure (1a-11 to 1a-mn) via an electric current is checked against the ground potential (71a-). 11 to 71a-mn), and based on the measurement result, it is judged whether or not a low grounded object is in contact with the foundation beam 33, and whether or not a current outflow occurs due to the interference of stray current. The process of performing either one or both of the determinations will be described.

Each of the potential measuring machines 60a-11 to 60a-mn is a coupon 72a- connected to the steel foundation beam 33 of the base portion 30 of the base structure (1a-11 to 1a-mn) via an electric wire. The ground potential of 11 is measured with a reference electrode (71a-11 to 71a-mn), and the ground potential measurement information including the information indicating the measurement result of the ground potential, the identification information of the foundation beam 33, and the measurement time information is created. Then, the created ground potential measurement information is transmitted to the monitoring device 100.
(Step S1)
The communication unit 110 of the monitoring device 100 receives the ground potential measurement information transmitted by each of the potential measuring machines 60a-11 to the potential measuring machine 60a-mn, and outputs the received ground potential measurement information to the information processing unit 130. ..
The reception unit 131 of the information processing unit 130 acquires a plurality of ground potential measurement information output by the communication unit 110, and receives the acquired plurality of ground potential measurement information.

(Step S2)
The processing unit 132 acquires a plurality of ground potential measurement information output by the reception unit 131, and acquires information indicating the measurement result of the ground potential included in each of the acquired plurality of ground potential measurement information. The processing unit 132 determines whether or not the potential measurement result has changed by the potential threshold value or more based on each of the acquired information indicating the measurement results of the plurality of ground potentials.
(Step S3)
When all the measurement results of the plurality of potentials do not change by the potential threshold value or more, the processing unit 132 means that no other metal object is in contact with all the steel materials conducting with the steel foundation beam 33, and the stray current is generated. It is determined that no current outflow due to interference has occurred.
(Step S4)
When at least one of the measurement results of the plurality of potentials changes by the potential threshold value or more, the processing unit 132 determines whether or not the measurement results of the plurality of potentials have changed on the base side.

(Step S5)
When the measurement results of the plurality of ground potentials do not fluctuate on the base side, the processing unit 132 determines that the low ground contact object is in contact with the foundation beam 33. When the processing unit 132 determines that the low grounded object is in contact with the foundation beam 33, the processing unit 132 outputs information indicating that the low grounded object is in contact with the foundation beam 33 to the display unit 150. When the processing unit 132 determines that the low grounded object is in contact with the foundation beam 33, the processing unit 132 indicates that the low grounded object is in contact with the foundation beam 33 and the identification information of the steel foundation beam 33. The low ground contact occurrence information including the information associated with the information indicating the measurement result of the ground potential is created, and the created low ground contact occurrence information is output to the specific unit 133.
(Step S6)
The specific unit 133 acquires information that associates the identification information of the steel foundation beam 33 included in the acquired low ground contact occurrence information with the information indicating the measurement result of the ground potential. The identification unit 133 derives the position of the floor slab in contact with the low ground contact object based on the information associated with the acquired identification information of the steel foundation beam 33 and the information indicating the measurement result of the ground potential. The identification unit 133 derives the position where the low ground contact object comes into contact with the information based on the information associated with the acquired identification information of the steel foundation beam 33 and the information indicating the measurement result of the ground potential. The identification unit 133 outputs information indicating the position where the derived low ground object comes into contact with the display unit 150 to the display unit 150.
When a low grounded object comes into contact, the potential of the foundation beam 33 rises. In this case, the potential of the foundation beam 33 can be lowered by removing the low grounded object based on the position where the low grounded object is in contact.

(Step S7)
When the measurement results of the plurality of ground potentials fluctuate on the base side, the processing unit 132 determines that a current outflow has occurred due to the interference of the stray current. When it is determined that a current outflow has occurred due to the interference of the stray current, the processing unit 132 outputs information indicating that the current outflow has occurred due to the interference of the stray current to the display unit 150. When the processing unit 132 determines that a current outflow has occurred due to the interference of the stray current, the processing unit 132 indicates that the current outflow has occurred due to the interference of the stray current, the identification information of the steel foundation beam 33, and the ground potential. The current outflow generation information due to the interference of the stray current including the information associated with the information indicating the measurement result of the above is created, and the current outflow generation information due to the interference of the created stray current is output to the specific unit 133.
(Step S8)
The specific unit 133 acquires the current outflow generation information due to the interference of the stray current output by the processing unit 132, and the identification information of the steel foundation beam 33 included in the current outflow generation information due to the interference of the acquired stray current, and the ground. The information associated with the information indicating the measurement result of the electric potential is acquired. The identification unit 133 derives the position of the floor slab in which the current outflow due to the interference of the stray current has occurred, based on the acquired identification information of the steel foundation beam 33 and the information indicating the measurement result of the ground potential. Based on the information in which the acquired identification information of the steel foundation beam 33 and the information indicating the measurement result of the ground potential are associated with the specific unit 133, the current outflow due to the interference of the stray current is generated from the measurement result of the ground potential. Derive the location where it occurred. The specific unit 133 outputs information indicating a location where a current outflow occurs due to the interference of the derived stray current to the display unit 150.
When a current outflow occurs due to the interference of the stray current, corrosion becomes a problem because the outflow current is large in the place where the potential is high. In this case, the current can be reduced by inserting a resistor into the circuit of the magnesium electrode. If the potential does not decrease even if a resistor is inserted into the circuit of the magnesium electrode, the potential can be decreased by adding magnesium.

With reference to FIG. 25, the measurement result of the current flowing from the current supply unit (51a-11 to 51a-mn) to the steel foundation beam 33 of the foundation portion 30 of the foundation structure and the pile reinforcing bar conducting to the steel foundation beam 33. Based on the above, a process of determining whether or not a low grounded object is in contact with the foundation beam 33 and determining whether or not a current outflow occurs due to interference of stray current, or both of them will be described. To do.
Each of the current measuring machines 70a-11 to 70a-mn conducts from the current supply part (51a-11 to 51a-mn) to the steel foundation beam 33 of the foundation part 30 of the foundation structure and the current beam 33. The current flowing through the pile reinforcing bar is measured, information indicating the measurement result of the current, identification information of the foundation beam 33, and current measurement information including measurement time information are created, and the created current measurement information is monitored by the monitoring device. Send to 100.
(Step S11)
The communication unit 110 of the monitoring device 100 receives the current measurement information transmitted by each of the current measuring machines 70a-11 to the current measuring machine 70a-mn, and outputs the received current measurement information to the information processing unit 130.
The reception unit 131 of the information processing unit 130 outputs a plurality of received current measurement information to the processing unit 132.
(Step S12)
The processing unit 132 acquires a plurality of current measurement information output by the reception unit 131, and acquires information indicating a current measurement result included in each of the acquired current measurement information. The processing unit 132 determines whether or not the current measurement result has changed by the current threshold value or more based on each of the acquired information indicating the measurement results of the plurality of currents.
(Step S13)
When all of the measurement results of the plurality of currents do not change by the current threshold value or more, the processing unit 132 means that no other metal object is in contact with all the steel materials conducting with the steel foundation beam 33, and the stray current is generated. It is determined that no current outflow due to interference has occurred.
(Step S14)
When at least one of the measurement results of the plurality of currents changes by the current threshold value or more, the processing unit 132 determines whether or not there is any decrease in the measurement results of the plurality of currents.
(Step S15)
If there is no decrease in the measurement results of the plurality of currents, the processing unit 132 determines that the low grounded object is in contact with the foundation beam 33. When the processing unit 132 determines that the low grounded object is in contact with the foundation beam 33, the processing unit 132 outputs information indicating that the low grounded object is in contact with the foundation beam 33 to the display unit 150. Here, the specific unit 133 may derive the position of the floor slab in which the low ground contact object is in contact with the foundation beam 33 based on the measurement results of a plurality of currents.

(Step S16)
When the measurement results of the plurality of currents are reduced, the processing unit 132 determines that a current outflow has occurred due to the interference of the stray current. When it is determined that the current outflow due to the interference of the stray current has occurred, the processing unit 132 outputs information indicating that the stray current has occurred to the display unit 150. Here, the specific unit 133 may derive the position of the floor slab in which the current outflow due to the interference of the stray current has occurred, based on the measurement results of the plurality of currents.
After step S15, the processing unit 132 associates the information indicating that the low ground contact object is in contact with the foundation beam 33, the identification information of the steel foundation beam 33, and the information indicating the measurement result of the ground potential. The low ground contact occurrence information including the above information may be created, and the created low ground contact occurrence information may be output to the specific unit 133.
The specific unit 133 acquires information that associates the identification information of the steel foundation beam 33 included in the acquired low ground contact occurrence information with the information indicating the measurement result of the ground potential. The identification unit 133 derives the position where the low ground contact object comes into contact with the acquired identification information of the steel foundation beam 33 and the information associated with the information indicating the measurement result of the ground potential. The identification unit 133 outputs information indicating the position where the derived low ground object comes into contact with the display unit 150 to the display unit 150.
When a low grounded object comes into contact, the potential of the foundation beam 33 rises. In this case, the potential of the foundation beam 33 can be lowered by removing the low grounded object based on the position where the low grounded object is in contact.

After step S16, the processing unit 132 associates information indicating that a current outflow has occurred due to interference of the stray current, identification information of the steel foundation beam 33, and information indicating the measurement result of the ground potential. The current outflow generation information due to the interference of the stray current including the above may be created, and the created stray current generation information may be output to the specific unit 133.
The specific unit 133 acquires the current outflow generation information due to the interference of the stray current output by the processing unit 132, and the identification information of the steel foundation beam 33 included in the current outflow generation information due to the interference of the acquired stray current, and the ground. The information associated with the information indicating the measurement result of the electric potential is acquired. Based on the information in which the acquired identification information of the steel foundation beam 33 and the information indicating the measurement result of the ground potential are associated with the specific unit 133, the current outflow due to the interference of the stray current is generated from the measurement result of the ground potential. Derive the location where it occurred. The specific unit 133 outputs information indicating a location where a current outflow occurs due to the interference of the derived stray current to the display unit 150.
When a current outflow occurs due to the interference of the stray current, corrosion becomes a problem because the outflow current is large in the place where the potential is high. In this case, the current can be reduced by inserting a resistor into the circuit of the magnesium electrode. If the potential does not decrease even if a resistor is inserted into the circuit of the magnesium electrode, the potential can be decreased by adding magnesium.

In the above-described embodiment, the case where the first insulating member 40 is included in the basic structure 1 has been described, but the present invention is not limited to this example. For example, the first insulating member 40 may be removed from the foundation structure 1.
In the above-described embodiment, the case where the pile insulating member 42 is painted on the outer peripheral surface of the pile 10 has been described, but the present invention is not limited to this example. For example, the pile insulating member 42 may not be painted on the outer peripheral surface of the pile 10.
In the above-described embodiment, the case where the monitoring system 200 includes one monitoring device 100 has been described, but the present invention is not limited to this example. For example, the monitoring system 200 may include a plurality of monitoring devices 100.
In the above-described embodiment, the case where the monitoring system 200 determines that the current outflow has occurred due to the interference of the stray current and the determination that the low grounded object has come into contact has been described, but this is limited to this example. I can't. For example, the monitoring system 200 may make either a determination that a current outflow has occurred due to interference of a stray current or a determination that a low grounded object has come into contact with the monitoring system 200.
According to the monitoring system 200 according to the embodiment, the monitoring device 100 can determine that a current outflow has occurred due to interference of a stray current, which is a concern in the corrosion protection of the foundation beam made of system steel, and the direction in which the stray current has flowed. Can be derived. Therefore, a resistor is inserted in the magnesium electrode circuit to reduce the current. If the potential does not drop to the design value due to the resistance alone, measures such as adding magnesium can be taken.
Further, the monitoring device 100 can determine that a low grounded object, which is a concern in the corrosion protection of the system steel foundation beam, has come into contact with the monitoring device 100, and can derive the position where the low contacted object has come into contact. Therefore, it is possible to take measures such as removing the low ground contact object based on the position where the low contact object is in contact.
In the above-described embodiment, the monitoring system 200 monitors the ground potential of the foundation beam 33 and the anticorrosion current generated by the anode, and based on the result of the monitor link, the presence or absence of contact with other metals and the interference of the stray current. The case of detecting the presence or absence of current outflow due to the above has been described, but the present invention is not limited to this example. For example, the monitoring system 200 may monitor the ground potential of the foundation beam 33 and detect the presence or absence of contact with other metals and the presence or absence of current outflow due to the interference of stray current based on the result of the monitor link. The anticorrosion current generated by the anode may be monitored, and the presence or absence of contact with other metals and the presence or absence of current outflow due to the interference of stray current may be detected based on the result of the monitor link.
Although the embodiments have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, changes, and combinations can be made without departing from the gist of the invention. These embodiments are included in the scope and gist of the invention, and at the same time, are included in the scope of the invention described in the claims and the equivalent scope thereof.

The monitoring device 100 described above may be realized by a computer. In that case, a program for realizing the function of each functional block is recorded on a computer-readable recording medium. The program recorded on the recording medium may be read by the computer system and executed by the CPU. The term "computer system" as used herein includes hardware such as an OS (Operating System) and peripheral devices.
Further, the "computer-readable recording medium" refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, or a CD-ROM. Further, the "computer-readable recording medium" includes a storage device such as a hard disk built in a computer system.

Further, the "computer-readable recording medium" may include a medium that dynamically holds the program for a short period of time. What dynamically holds the program for a short period of time is, for example, a communication line when the program is transmitted via a network such as the Internet or a communication line such as a telephone line.
Further, the "computer-readable recording medium" may include a medium that holds a program for a certain period of time, such as a volatile memory inside a computer system serving as a server or a client. Further, the above program may be for realizing a part of the above-mentioned functions. Further, the above-mentioned program may be realized by combining the above-mentioned functions with a program already recorded in the computer system. Further, the above program may be realized by using a programmable logic device. The programmable logic device is, for example, an FPGA (Field Programmable Gate Array).

The monitoring device 100 described above has a computer inside. The process of each process of the monitoring device 100 described above is stored in a computer-readable recording medium in the form of a program, and the process is performed by the computer reading and executing this program.
Here, the computer-readable recording medium refers to a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Further, this computer program may be distributed to a computer via a communication line, and the computer receiving the distribution may execute the program.
Further, the above program may be for realizing a part of the above-mentioned functions.
Further, a so-called difference file (difference program) may be used, which can realize the above-mentioned functions in combination with a program already recorded in the computer system.

1 Foundation structure 10 Pile 11 Pile rebar 20 Floor slab 21 Slab rebar 30 Foundation part 31 Pile head joint 32 Strut 33, 33ab-11 to 33ab-mn, 33bd-11 to 33bd-mn, 33dc-11 to 33dc-mn , 33ca-11 to 33ca-mn Foundation beam 40 First insulating member 43 Second insulating member 50 Network 51a-11 to 51a-mn Current supply unit 52 Sacrificial electrode 60a-11 to 60a-mn Potential measuring machine 70a-11 to 70a -Mn Current measuring machine 71a-11 to 71a-mn Collation electrode 72a-11 to 72a-mn Coupon 100 Monitoring device 110 Communication unit 120 Storage unit 130 Information processing unit 140 Operation unit 150 Display unit

Claims (10)

A concrete slab buried in the soil and having a plurality of pile reinforcements arranged inside, and a concrete floor slab installed on the surface of the soil and having a plurality of slab reinforcements arranged inside. A steel foundation that connects the pile to the floor slab and at least partially buried in the soil, the foundation being connected to the upper end of the pile. The foundation of a foundation structure including a head joint, a steel strut extending upward from the pile head joint, and a steel foundation beam extending horizontally from the strut and supporting the floor slab. A current supply unit that supplies anticorrosion current to the unit and
A reception unit that receives information indicating the ground potential of the foundation portion of the foundation structure, and
Based on the information indicating the ground potential received by the reception unit, it is determined whether or not a low grounded object is in contact with the foundation portion, and a current outflow due to the interference of the stray current occurs in the steel foundation portion. A monitoring system including a processing unit that performs one or both of determinations as to whether or not the information is present. The reception unit receives information indicating the anticorrosion current generated by the anode, and receives information.
Based on the information indicating the anticorrosion current received by the reception unit, the processing unit further determines whether or not a low grounded object is in contact with the foundation unit, and a current outflow occurs due to the interference of the stray current. The monitoring system according to claim 1, wherein one or both of the determination is performed. The reception unit receives information indicating the ground potential of each of the foundation parts of the plurality of foundation structures.
The monitoring system
Based on the information indicating the ground potential of each of the foundations of the plurality of foundations received by the reception, the derivation of the position where the low ground object is in contact with the foundation and the interference of the stray current. The monitoring system according to claim 1 or 2, further comprising a specific unit that performs either or both of deriving the position where the current outflow is occurring. Based on the plane defined by the information indicating the ground potential at least three places, the specific part derives the position where the low ground object is in contact with the base part, and the current outflow occurs due to the interference of the stray current. The monitoring system according to claim 3, wherein one or both of the derivation of the position is performed. The receiving unit receives information indicating the anticorrosion current generated by each of the plurality of anodes by each of the plurality of current supply units supplying a current to each foundation of the plurality of basic structures.
Based on the information indicating the anticorrosion current generated by each of the plurality of anodes received by the receiving unit, the derivation of the position where the low grounded object is in contact with the foundation and the current outflow due to the interference of the stray current are generated. The monitoring system according to claim 1, further comprising a specific unit that performs either or both of the derivation of the generated position. A concrete slab buried in the soil and having a plurality of pile reinforcements arranged inside, and a concrete floor slab installed on the surface of the soil and having a plurality of slab reinforcements arranged inside. A steel foundation that connects the pile to the floor slab and at least partially buried in the soil, the foundation being connected to the upper end of the pile. The foundation of a foundation structure including a head joint, a steel strut extending upward from the pile head joint, and a steel foundation beam extending horizontally from the strut and supporting the floor slab. The step of supplying current to the part and
A step of receiving information indicating the ground potential of the foundation portion of the foundation structure, and
Based on the information indicating the ground potential received in the accepting step, it is determined whether or not a low grounded object is in contact with the foundation portion and whether or not a current outflow occurs due to the interference of stray current. A monitoring method performed by a monitoring system that has steps to do one or both of the above. In the accepting step, information indicating the ground potential of each of the foundations of the plurality of foundation structures is received.
The monitoring method is
Based on the information indicating the ground potential of each of the foundation portions of the plurality of foundation structures received in the acceptance step, the position where the low ground contact object is in contact with the foundation portion is derived, and the stray current interferes. The monitoring method according to claim 6, further comprising a specific step of deriving one or both of the locations where the current outflow is occurring. A potential measuring machine for measuring the ground potential is installed in each of the floor slabs of the plurality of foundation structures.
In the specific step, one or both of the derivation of the position of the floor slab in which the low ground contact object is in contact with the foundation portion and the derivation of the position of the floor slab in which the current outflow occurs due to the interference of the stray current, or both. 7. The monitoring method according to claim 7. In the accepting step, information indicating the anticorrosion current generated by each of the plurality of anodes is received by supplying a current to each foundation portion of the plurality of foundation structures.
The monitoring method is
Based on the information indicating the anticorrosion current generated by each of the plurality of anodes received in the accepting step, the derivation of the position where the low grounded object is in contact with the base portion and the current outflow due to the interference of the stray current The monitoring method according to claim 6, further comprising a specific step of deriving one or both of the locations where they are occurring. A current measuring machine for measuring the anticorrosion current is installed in each of the floor slabs of the plurality of foundation structures.
In the specific step, one or both of the derivation of the position of the floor slab in which the low ground contact object is in contact with the foundation portion and the derivation of the position of the floor slab in which the current outflow occurs due to the interference of the stray current. 9. The monitoring method according to claim 9.

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