JP2003262580A - Method for diagnosing corrosion of object embedded underground, corrosion diagnosing program, recording medium recording corrosion diagnosing program, and corrosion diagnosing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To estimate the remaining lives of objects made of steel and embedded underground by automatically diagnosing their corrosion and degradation conditions according to both use environments and the number of installed years of each object made of steel and embedded underground to be measured. <P>SOLUTION: The corrosion conditions of the objects embedded underground are classified and sampled to determine the number of usable years for every environment conditions. The numbers of years for replacing the objects embedded underground are determined from the dates of embedding of the objects embedded underground, their environment conditions, and their numbers of usable years. This method is implemented by the function of an information input means 25 for inputting the installation environments and numbers of installed years of the objects to be diagnosed made of steel and embedded underground as input information to a computer 21, the function of a corrosion and degradation degree determining means 26 for determining the degree of corrosion and degradation of the objects made of steel and embedded underground on the basis of the installation environments and the numbers of installed years inputted from the information input means 25 according to corrosion and degradation determination criteria 29, and the function of a remaining life estimating means 27 for estimating the remaining lives of the objects made of steel and embedded underground on the basis of the degree of corrosion and degradation determined by the corrosion and degradation degree determining means 26. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to corrosion of underground buried objects used for estimating the remaining life by performing corrosion deterioration diagnosis of underground buried steel objects such as steel pipe utility poles and branch line anchors. The present invention relates to a diagnostic method, a program for implementing the method, a computer-readable recording medium recording the program, and a corrosion diagnostic apparatus.

[0002]

2. Description of the Related Art FIGS. 8 and 9 show a conventional example of a support structure for a telephone pole. In this support structure, by being buried in the underground portion 1, a steel pipe-made telegraph pole 3 is provided above the ground surface 2, a branch line 4 is connected to the tip of this telegraph pole 3, and this branch line 4 is connected to a branch line rod 5. The telephone pole 3 is supported by being connected to the branch line anchor 6 in the ground through the above.

Since the telephone pole 3 and the branch line anchor 6 are buried in the ground, they may be corroded by long-term use. However, the state of corrosion of the telephone pole 3 and the branch line anchor 6 buried in the ground. It is not easy to grasp
These corrosion conditions are indirectly measured by the following methods. That is, the following method has been proposed as a method of diagnosing the quality deterioration of the branch line anchor 6 due to soil corrosion. (A) Striking vibration method The part of the branch line rod 5 connected to the branch line anchor 6 that is exposed to the ground is hit, and thinning due to corrosion of the branch line rod 5 itself or the branch line anchor 6 is judged from the vibration characteristics obtained at that part. (B) Ultrasonic flaw detection method Ultrasonic waves oscillated from an ultrasonic generator are made incident from the branch rod 5, and the reflected wave obtained at the end face of the rod portion 5 is analyzed to determine the thinning due to the above-mentioned corrosion. (C) Soil resistivity measurement method The soil resistivity of the soil in which the branch line anchor 6 is buried is measured to determine whether or not the soil (atmosphere) is highly corrosive. (D) Polarization resistance measurement method The test electrode is polarized, and the polarization resistance at this time is measured,
Convert this to the corrosion rate.

Further, as a method of diagnosing quality deterioration due to soil corrosion in the underground portion of a telephone pole, there is a method using an ultrasonic thickness gauge. In this method, as shown in FIG.
The ultrasonic sensor portion 13 connected to the measuring device main body 11 via the lead wire 12 is inserted into the pipe from the scaffold mounting hole 15 of the hollow steel pipe telephone pole 14 whose lower end portion is buried in the ground 16, and the iron rust is formed. Ultrasonic waves are generated by contacting the inner surface of the part where no noise is generated. Further, the ultrasonic wave reflected by the ultrasonic wave is received by the ultrasonic wave sensor unit 13, and the thickness of the pipe wall is measured by measuring this with the measuring device main body 11, and the value is stored as an initial thickness in a memory (not shown). And display it on a display (not shown). Then, the ultrasonic sensor unit 13 is lowered to the vicinity of the lowermost portion of the steel pipe telephone pole 14, the thickness of the pipe wall is measured in the same manner as above, and the value is recorded and displayed in the same manner as above. Furthermore, the ultrasonic sensor unit 13 is
The same measurement and recording are performed multiple times by pulling up by 0 cm, and the minimum value of the wall thickness of the pipe is selected from these, and this is subtracted from the initial thickness to obtain the corrosion thickness, and this is used for quality deterioration. The diagnostic criteria for

[0005]

However, each of the branch line anchor and the utility pole deterioration measuring method has the following problems to be solved. In the above-mentioned percussion vibration method, since the branch line is divided into a rod, a connecting portion, a guide plate, and the like and has a plurality of fulcrums, the vibration mode is complicated and vibration analysis cannot be performed with high accuracy. In the ultrasonic flaw detection method described above, since the rod, the connecting portion, and the guide plate are independent at a plurality of fulcrums, the ultrasonic wave is greatly attenuated, and as a result, the measurement sensitivity of the reflected wave and the measurement result vary. There was a problem. Further, since ultrasonic waves are incident from a branch rod that is buried obliquely in the ground, there is a problem that attenuation is large and it is difficult to detect reflected waves on the ground.

[0006] In the soil resistivity method, there is no clear correspondence between the soil resistivity and the corrosion rate of the branch line anchor, and it is difficult to determine whether or not the environment is corrosive. . In the polarization resistance measuring method, there is a problem that the shape of the branch line anchor cannot be accurately reflected because the corrosion measurement cannot be directly performed on the branch line anchor.

On the other hand, in the method of diagnosing the deterioration of the quality of the steel pipe telephone pole by utilizing ultrasonic waves, the ultrasonic sensor portion is inserted into the pipe for measurement, so that the workability of measurement is poor and the diagnosis requires a long time. There was a problem that the cost was high. As described above, it is difficult to reliably determine the life by the above-mentioned method of determining the life, and in order to ensure the safety and reliability of the equipment, it is unavoidable to replace it at regular intervals regardless of the life. As a result, there was a problem that economic efficiency deteriorated.

The present invention solves the above-mentioned problems, and automatically diagnoses the corrosion deterioration state according to the use environment and the number of years of installation for each steel underground buried object to be measured,
The purpose is to enable estimation of the remaining life of steel underground buried objects and determination of the number of years for renewal.

[0009]

[Means for Solving the Problems] To achieve the above object,
The method of the present invention includes, for example, a step of classifying and corroding a corrosion state of a steel underground buried object for each buried environmental condition, and a usable life of the underground buried object for each classified environmental condition. Determining the time of burial of the underground buried object to be judged, the environmental conditions, and the determined number of usable years to determine the renewal time of the underground buried object to be judged. And a process. Further, the above-mentioned corrosion state is characterized in that it is judged by a reduction amount of an outer diameter dimension per unit time due to corrosion of a buried object. Further, the environmental conditions include a highly corrosive environment including a buried land that contacts seawater or acidic water, a corrosive environment including a buried land that contacts moisture except seawater and acidic water, and a drainage that is difficult to contact with water including seawater and acidic water. It is characterized by being categorized into four types: low-corrosion environment including well-filled land, high-corrosion environment, corrosion environment, and soil environment other than low-corrosion environment. Further, a part of the underground buried object is buried in the ground, is supported by the buried part, and the other part exists above the surface of the ground. Further, the underground buried object is characterized in that it is entirely buried in the ground. With this method, it is possible to easily and quickly estimate the remaining life without directly touching the steel underground buried object which is the measurement object with the sensor or the like.

Further, the program of the present invention includes a process of inputting an installation environment and an installation year of an underground buried object to be diagnosed,
Based on the input installation environment and installation years, reference is made to the corrosion deterioration degree determination reference data, and a process of determining the corrosion deterioration degree of the underground buried object, and the process based on the determined corrosion deterioration degree And a process for estimating the remaining life of the medium buried object. This allows the computer to access the information on the recording medium,
Quickly diagnose the remaining life of underground buried objects anytime, anywhere
It can be done easily.

Further, the recording medium of the present invention is provided with a process for inputting the installation environment and the installation years of the underground buried object to be diagnosed, and based on the input installation environment and the installation years, the corrosion deterioration degree judgment reference data. With reference to the above, it is characterized by comprising a process of determining a corrosion deterioration degree of the underground buried object and a process of estimating a remaining life of the underground buried object based on the determined corrosion deterioration degree. . Similarly, when the information on the recording medium is accessed by the computer,
The remaining life of underground buried objects can be quickly and easily diagnosed anywhere.

The diagnostic device of the present invention is a device for diagnosing corrosion of an underground buried object, and an information input means for inputting the installation environment and the number of years of installation of the steel underground buried object to be diagnosed as input information. A corrosion deterioration degree judging means for judging the corrosion deterioration degree of the underground buried object by referring to the corrosion deterioration degree judgment reference data based on the installation environment and the installation years inputted from the information input means; And a remaining life estimating means for estimating the remaining life of the underground buried object based on the corrosion deterioration degree judged by the deterioration degree judging means. As a result, it is possible to estimate the remaining life of the underground buried object in which the progress of corrosion deterioration cannot be quantified easily and at low cost.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. First, the general tendency of corrosion of buried objects in the ground will be described with reference to FIG. The horizontal axis of Fig. 3 shows the number of years that have passed since it was buried in the ground, and the vertical axis shows the maximum corrosion depth caused by corrosion (the maximum value of the outer diameter dimension of each sample that was reduced by the corrosion). Most of the samples have a decrease of 0 to 2 mm (mostly 1 mm or less) over the past 20 to 30 years. Further, when the frequency distribution of the maximum corrosion depth is examined from the above data, as shown in FIG. 4, most of the samples have a corrosion depth of 1 mm or less.

Further, the corrosion depth (mm) generated in a certain sample is divided by the years of use (yr) to obtain the corrosion rate (mm /
yr) as an index, corrosive environment (soil that is judged to be corroded easily by detecting specific resistance below a certain level), seawater environment, water-affected environment such as gutters and waterways, former paddy field (formerly paddy field) Fig. 5 shows the frequency distribution by classifying the samples into each environment, that is, wet environment due to damage, landfill (wet environment due to landfill), and paddy field (wet environment such as paddy field except for ridges). On the street. That is, the frequency distribution of the corrosion rate depending on the nature of water (whether there is an acidic component or salt having a strong corrosive force) that causes corrosion is obtained. Further, using the corrosion rate as an index, a corrosive environment (soil which is determined to be susceptible to humus by detecting a specific resistance not higher than a predetermined value),
FIG. 6 shows the frequency distribution obtained by classifying the samples into the environments of constant humidity, high humidity, and good daily conditions. That is, the frequency distribution of the corrosion rate depending on the amount of water that causes corrosion is obtained. Furthermore, when the corrosion rate is used as an index, samples are classified into reclaimed land, tidal land, delta, wetland, land reclamation area, electrolytic corrosion area, paleo soil, and ordinary soil to summarize the frequency distribution. On the street. That is, the classification of the above-mentioned buried land is classified according to the cause of its formation, for example, a reclaimed land or a tidal land having a high salt content, or an environment where the water content is high due to poor drainage. These soil environments can be statistically classified because they are classified and the land is classified as a well-drained environment.

From the analysis of the frequency distributions in FIGS. 5 to 7 based on the measured values of the corrosion rate of the sample, the degree of corrosion of the underground buried object should be classified as shown in Table 1 below. You can

[Table 1] The corrosive environment classification was obtained by analyzing the data of the above samples, and excludes high corrosive environment pavement roads such as places affected by seawater in tidal areas and coastal lowlands, and areas wet in acidic hot springs. In a paddy field, a place affected by water in or near a gutter canal, a fallow field or landfill that is a field or a wasteland, etc. Good, low-corrosion environment corresponding to well-drained place It can be classified into four general environments which are soil environments other than the above-mentioned high-corrosion environment, corrosive environment and low-corrosion environment. Deterioration A> Degradation B> Degradation C
> Deterioration decreases in the order of deterioration D. It is expected that the expected function can be maintained with a probability of approximately 95% by determining the number of years of renewal for each environment based on the amount of corrosion obtained experimentally. The effect on the strength of branch line anchors when a certain amount of corrosion occurs tends to decrease as the size of the branch line anchors increases.Therefore, it is also possible to lengthen the renewal period as the size of the branch line anchors increases. Is. In addition, regarding branch line anchors, according to experiments, the number of years of renewal is 25 years in a highly corrosive environment and 4 years in a corrosive environment.
0 years, 100 years in low corrosion environment, 70 years in general environment.

By using Table 1 created as described above as a database, it is possible to determine whether the buried environment is classified according to the property of the buried object, the date and time of the buried object (when buried), and the environment in which it is buried. It is possible to know the life of the buried object, or the number of renewal years determined based on the life of the buried object in consideration of a predetermined safety factor.

FIG. 1 is a block diagram showing a corrosion diagnosing device for a steel underground buried object used for carrying out the above corrosion diagnosing method. Reference numeral 21 is a computer for diagnosing corrosion of underground steel products.
And are provided. Further, in the processing unit 22, through the interface 24, the information input means 25 for taking in input information such as the installation environment and the years of installation of the steel underground buried object to be diagnosed, and the steel taken in the information input means 25. Corrosion deterioration degree judgment for judging the corrosion deterioration degree of the steel underground buried object according to the corrosion deterioration degree judgment standard 29 stored in the storage unit 23 based on each information of the underground buried object, the installation environment and the installation years Means 26 and this corrosion deterioration degree judging means 2
Remaining life estimating means 27 for estimating the remaining life of the steel underground buried object based on the corrosion deterioration degree information determined in 6.
And a renewal year determination means 28 for determining the renewal year of the steel underground buried object from the estimated life.

In addition to the corrosion deterioration level determination standard, the storage unit 23 also stores a remaining service life determination standard 30, which is a standard for determining the remaining service life, and installation environment information 31 mainly about soil. Among these, the corrosion deterioration degree determination standard 29 is, for example, in the case of a branch line anchor, the earth and sand attached to the buried branch line anchor are removed, and the diameter of the minimum diameter portion in the rod portion is determined by the guide plate portion. Then, set the thickness of the minimum cross-section multiple times using calipers (for example, 3 times).
The average minimum diameter and the average minimum plate thickness obtained by measuring and averaging these are obtained, and the corrosion deterioration degree and the installation environment and the number of installation years are statistically arranged, and a table such as Table 1 is formed into a storage unit. It is stored in 22. In addition, the remaining life judgment standard 30 uses the remaining life against the degree of corrosion deterioration, for example, the result of actually performing an electric resistance test or a proof stress test by applying an electrical or mechanical load to a steel underground buried object. Is set.

Here, the steel underground buried object to be diagnosed is a steel pipe telephone pole 14, a branch line anchor for the steel pipe telephone pole 14, a metal pole for signal or display, a foundation for construction or civil engineering. Widely includes steel materials such as steel materials. In addition, the installation environment as an environmental classification means, for example, tidal areas where steel underground buried objects are installed, coastal lowland areas, acidic hot spring areas, paddy fields, near ditch canals, fields, landfill sites, good sunlight, and good drainage. A place etc.

Next, a procedure for performing corrosion diagnosis and estimation of the remaining life by using such a corrosion diagnosis device for a steel underground buried object will be described. First, identify whether the steel underground buried object to be diagnosed is a steel pipe telephone pole or a branch line anchor (step ST), and further determine what soil corrosion environment (installation environment) this steel underground buried object is. Then, the number of years of use is sequentially input to the information input means 25 through the interface 24 using a keyboard or the like (steps S2 and S3). This information input means organizes these input information into information and inputs it to the corrosion deterioration degree determination means 26. The corrosion deterioration degree judging means 26 judges to what extent the specified steel underground buried object is corroded and deteriorated according to the corrosion deterioration degree judgment standard 29 stored in the storage unit 23 (step S4).
In the case where the steel underground buried object is the branch line anchor, for example, the criteria for determining whether the diameter of the rod or the minimum remaining area of the guide plate has decreased to a predetermined ratio (for example, 80%) or less with respect to the original dimension. And

Further, the result of the defect determination as the corrosion level made by the corrosion deterioration degree determining means 26 is the remaining life estimating means 2
Input to 7. The remaining life estimating means 27 checks how much the corrosion level of the steel underground buried object is higher or lower than the corrosion deterioration reference level of the memory section 23 based on the result of the defect determination, and the steel is evaluated. The remaining life of the buried object is estimated and calculated (step S5). In addition, in response to the estimation result of such remaining life, the renewal year determination means 28 newly updates the steel underground buried object according to the corrosive environment (installation environment) classification which is the installation environmental information of the steel underground buried object. The number of years to be exchanged (renewed) with another one is determined (step S6). It should be noted that the determination of the number of years of renewal can be made artificially according to the actual use condition without using the means for determining the number of years of renewal 28. Note that steps S1 to S
The information processing of No. 6 is executed in the procedure according to the program stored in the program storage unit 32.

The corrosion diagnosis program may be transmitted from a computer system having the program stored in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the "transmission medium" for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The corrosion diagnosis program may be for realizing some of the functions described above. Further, it may be a so-called difference file (difference program) that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

The information on the number of renewal years and the remaining life obtained in this way can be displayed on a display (not shown) via the interface 24 or can be printed out by a printer (not shown). Further, each environmental factor of the corrosion, from the cumulative frequency of corrosion rate obtained by dividing the decrease of the maximum cross-sectional area at this time corrosion of the underground steel buried object from galvanization to steel, at this time You can look it up.

The processes of measuring the remaining life of the steel underground buried object and determining the number of years of renewal in steps S1 to S6 are performed by a program stored in a program storage unit 32 such as a hard disk under the control of the computer 21. It is done according to the execution procedure, and therefore, the remaining life and the number of renewal years can be promptly determined. Further, by recording the program in a recording medium, for example, the hard disk described above, or a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM (not shown), the program can be used to record a location (such as a burial site). In (), it is possible to quickly and easily determine the life of the steel underground buried object by using a computer.

[0025]

As described above, according to the present invention, it is possible to quickly calculate and estimate the remaining life of an underground buried object made of steel, for example. In addition, the conventional vibration mode is a complicated vibration method, the ultrasonic deep scratch method has poor measurement sensitivity of reflected waves,
With a specific resistance higher than a predetermined level, it is difficult to classify the corrosive environment, and without using the soil resistivity method, the simple and low-cost configuration makes it possible to quantify the progress of corrosion deterioration. Can be accurately estimated. In addition, without touching human hands, measuring instruments, sensors, etc. with the steel underground buried object to be measured for measurement work, the information collected experimentally remains automatically by computer processing. The life can be estimated, and the result can be output and displayed or printed out as needed.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a corrosion diagnosis device for a steel underground buried object according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a procedure of executing a corrosion diagnosis by a corrosion diagnosis program for a steel underground buried object of the present invention.

FIG. 3 is a diagram showing the relationship between the maximum cross-sectional reduction of buried objects and the number of years elapsed.

FIG. 4 is a diagram showing a frequency distribution of maximum cross-section reduction of buried objects.

FIG. 5 is a diagram showing the cumulative frequency of corrosion rates of buried objects for each environment.

FIG. 6 is a diagram showing the cumulative frequency of corrosion rates of buried objects for each environment.

FIG. 7 is a diagram showing the cumulative frequency of the deficiency rate of buried objects for each environment.

FIG. 8 is an explanatory view of a conventional example of a branch line anchor.

9 is a detailed view of the underground portion of FIG.

FIG. 10 is an explanatory diagram showing a conventional method for diagnosing corrosion deterioration of a steel pipe telephone pole.

[Explanation of symbols]

21 computer 25 Information input means 26 Corrosion Degradation Determining Means 27 Remaining life estimation means 29 Corrosion Degradation Criteria

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Noriaki Takamatsu             3-19-2 Nishishinjuku, Shinjuku-ku, Tokyo Tohnichi             Inside Telegraph and Telephone Corporation F-term (reference) 2G050 AA01 AA06 BA02 BA20 EB10

Claims (8)

[Claims] 1. A step of classifying and corroding the corrosion state of an underground buried object for each buried environmental condition, and a step of determining the usable years of the underground buried object for each of the classified environmental conditions. Determining the number of renewal years of the underground buried object to be judged, from the time of burying the underground buried object to be judged, the environmental condition, and the determined usable years. A method for diagnosing corrosion of underground buried objects, which is characterized by the following. 2. The method for diagnosing corrosion of an underground buried object according to claim 1, wherein the corrosion status is determined by a reduction amount of an outer diameter dimension per unit time due to corrosion of the underground buried object. . 3. The environmental conditions include a highly corrosive environment including a buried land in contact with seawater or acid water, a corrosive environment including a buried land in contact with water except seawater and acidic water, and water containing seawater and acidic water. 3. The land according to claim 1 or 2, characterized by being classified into four types of low-corrosion environment including a well-drained land that is hard to contact, high-corrosion environment, corrosive environment, and soil environment other than low-corrosion environment. Corrosion diagnosis method for medium buried objects. 4. The underground buried object is partially buried in the ground, supported by the buried portion, and the other portion is above the surface of the ground. The method for diagnosing corrosion of an underground buried object according to any one of the above. 5. The corrosion diagnosis method for an underground buried object according to claim 1, wherein the entire underground buried object is buried in the ground. 6. A process for inputting an installation environment and an installation year of an underground buried object to be diagnosed, and referring to corrosion deterioration degree determination standard data based on the input installation environment and installation year, the above-mentioned site A corrosion diagnosis program for an underground buried object, comprising: a process for determining the corrosion deterioration degree of the intermediate buried object; and a process for estimating the remaining life of the underground buried object based on the determined corrosion deterioration degree. 7. A process of inputting an installation environment and an installation year of an underground buried object to be diagnosed, and referring to the corrosion deterioration degree determination standard data based on the input installation environment and installation year, the above-mentioned site A corrosion diagnosis program for underground buried objects, which is composed of processing for determining the degree of corrosion deterioration of medium buried objects and processing for estimating the remaining life of the underground buried objects based on the determined degree of corrosion deterioration, is recorded. Recording medium. 8. An apparatus for diagnosing corrosion of an underground buried object, comprising: an information input means for inputting an installation environment and an installation year of the underground buried object to be diagnosed as input information; and an information input means for inputting the information. Based on the installed environment and the number of years of installation, the corrosion deterioration degree judgment means for judging the corrosion deterioration degree of the underground buried object by referring to the corrosion deterioration degree judgment reference data, and the corrosion judged by the corrosion deterioration degree judgment means A corrosion diagnosing device for an underground buried object, comprising: a remaining life estimating means for estimating a remaining life of the steel underground buried object based on a degree of deterioration.