JP6273650B2 - PC sleeper deterioration determination system and PC sleeper deterioration determination method - Google Patents

Description

The present invention relates to a PC sleeper degradation determining system and PC sleeper deterioration determination how.

  The sleeper has a function of supporting the rails, maintaining a gap, and distributing and transmitting a load (action) transmitted from the rails to a roadbed laid under the sleepers. There are several types of roadbeds, and in particular, ballast such as stone cutting is often used. In addition, concrete sleepers that have a longer life than wooden sleepers are often used as sleepers.

When passing through the train, a tensile force due to the bending moment acts on the sleeper. Concrete is weak in tensile force in comparison with compressive force, and the tensile force may cause cracks in the concrete sleeper.
PC (Prestressed Concrete) sleepers are often used as countermeasures against cracks due to such tensile forces. The PC sleeper is configured by embedding a steel material (steel wire or steel bar) in concrete, and compressive force is introduced into the concrete by the steel material.

Thus, PC sleepers are strong in tensile force and have a relatively long life. However, even PC sleepers deteriorate with use and aging.
In particular, in the case of a PC sleeper laid on a ballast track, relative motion occurs between the PC sleeper and the ballast particles due to a dynamic load when passing through the train. The bottom surface of the PC sleeper is worn due to the sliding, rolling and impacting action of the ballast particles on the PC sleeper.

In addition, an excessive impact force may be generated between the wheel and the rail due to a factor due to the state of the wheel such as a flat wheel or a factor due to the state of the rail top such as a rail welded joint or rail joint. When such an impact force is transmitted to the PC sleeper, the PC sleeper may be cracked.
Note that Non-Patent Document 1 shows the results of investigation of the damage status of PC sleepers, and studies on repair and functional improvement of sleepers are being conducted.

Hitoshi Hasegawa and two others, "Causes and Countermeasures for PC Sleeper Damage", Proceedings of the 59th Annual Conference of Japan Society of Civil Engineers, 2004, Vol.59, 4-071, p.141-142

In order to properly manage PC sleepers, it is important to grasp the deterioration status of PC sleepers at the time of inspection. However, in the ballast track, since the PC sleeper can only see the upper surface and is mostly buried in the ballast, it is impossible to visually check the crack or wear of the bottom surface of the PC sleeper. If the ballast is scraped, it is possible to visually check the bottom surface of the PC sleeper, but the sectional height of the PC sleeper is usually 150 millimeters (mm) or more, and a large amount of labor is required for scraping the ballast.
Furthermore, it is not easy to visually check the cracks on the top surface that are not buried in the ballast because they are clogged or dirty with dust, and the cracks are opened only when loaded. The same applies to the visual confirmation of the bottom surface of the PC sleeper when the ballast is scraped.

The present invention provides a PC sleeper deterioration determination system and PC sleeper deterioration determination how can be more easily grasp the deterioration condition of the PC sleepers.

A PC sleeper deterioration determination system according to a first aspect of the present invention includes a microphone that acquires sound generated by vibration of a PC sleeper, a strap that can hang the microphone from a person, and a sound that the microphone acquires. And a natural frequency detecting unit for detecting the natural frequency of the third-order bending mode of the PC sleeper, and a natural frequency of the third-order bending mode detected by the natural frequency detecting unit is lower than a predetermined condition. A deterioration determining unit that determines that the PC sleeper has deteriorated when it is determined that the frequency is a frequency.

  The deterioration determining unit is configured to detect the third-order deflection detected by the first-order frequency detection unit using a predetermined ratio of the first-order natural frequency as a threshold value among the natural frequencies of the third-order bending mode of a plurality of PC sleepers. If it is determined that the natural frequency of the mode is lower than the threshold value, it may be determined that the PC sleeper to be determined is deteriorated.

  The deterioration determination unit is configured such that the natural frequency of the deflection tertiary mode detected by the natural frequency detection unit is lower than a threshold set based on the natural frequency of the deflection third mode of healthy PC sleeper. If it is determined that the PC sleeper is to be determined, it may be determined that the PC sleeper to be determined has deteriorated.

In the PC sleeper deterioration judging method according to the second aspect of the present invention, a sound collecting step of acquiring a sound generated by vibration of the PC sleeper with a microphone suspended from a person by a strap, and the sound collecting step A natural frequency detecting step for detecting the natural frequency of the third-order bending mode of the PC sleeper based on the sound acquired in step 3, and a natural vibration of the third-order bending mode detected in the natural frequency detecting step. A deterioration determining step that determines that the PC sleeper has deteriorated when the number is determined to be lower than a predetermined condition.

  According to the present invention, the deterioration state of PC sleepers can be grasped more easily.

It is a schematic external view which shows the example of the external shape of the PC sleeper deterioration determination system in one Embodiment of this invention. It is a schematic block diagram which shows the function structure of the PC sleeper deterioration determination system 1 in the embodiment. It is explanatory drawing shown in the figure which looked at the vibration position by the hammer 210 in the same embodiment from the top. It is explanatory drawing which shows the vibration position by the hammer 210 in the same embodiment in the figure which looked at the PC sleeper from the side. It is a graph which shows the example of the change of the natural frequency by deterioration of PC sleeper. It is explanatory drawing which shows the example of the magnitude | size of the vibration in each position of PC sleeper by the bending 3rd mode natural vibration. It is a graph which shows the example of the change of the natural frequency by the change of the supporting force of a ballast roadbed or a roadbed. It is a graph which shows the example of the change of the natural frequency by the change of the both-ends support force with respect to PC sleeper. It is a flowchart which shows the example of the procedure of the process which the PC sleeper deterioration determination system 1 in the embodiment performs. It is a flowchart which shows the example of the process sequence in which the natural frequency detection part 191 in the embodiment detects a bending | flexion tertiary mode natural frequency. It is explanatory drawing which shows the 1st example of the process sequence which the deterioration determination part 192 in the embodiment performs deterioration determination of PC sleeper. It is explanatory drawing which shows the 2nd example of the process sequence which the deterioration determination part 192 in the embodiment performs deterioration determination of PC sleeper. It is a graph which shows the example of a detection of the bending | flexion 3rd mode natural frequency of the pretension PC sleeper by the analysis of the sound in the same embodiment. It is explanatory drawing which shows the load position in the loading test in the same embodiment. In the figure, a line CL indicates the center position of the PC sleeper. It is a graph which shows the measurement result of the 3rd mode natural frequency in the loading test in the embodiment. It is a schematic external view which shows the example of the external shape of the PC sleeper deterioration determination system which has an acceleration sensor. It is explanatory drawing which shows the example of the installation position of the acceleration sensor 320. FIG. It is explanatory drawing which shows the vibration position in the comparative test of the embodiment. It is a graph which shows the detection success rate of the 3rd mode natural frequency in the embodiment. It is a graph which shows the 3rd mode natural frequency obtained by vibrating near the center of PC sleeper in the embodiment.

Hereinafter, although embodiment of this invention is described, the following embodiment does not limit the invention concerning a claim. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.
FIG. 1 is a schematic outline view showing an example of the external shape of a PC sleeper deterioration determination system according to an embodiment of the present invention. In FIG. 1, the PC sleeper deterioration determination system 1 includes a main body device 10, a strap 11, and a hammer 210. The main device 10 includes a recording diagnostic device 100 and a microphone 220. The hammer 210 and the recording diagnostic device 100 are connected by a signal line such as a BNC coaxial cable.

The hammer 210 vibrates the PC sleeper. Further, the hammer 210 includes an acceleration sensor, and transmits an excitation force (particularly, a signal indicating the excitation timing and the intensity of the excitation) to the recording diagnostic device 100.
As the hammer 210, it is preferable to use an impulse hammer for vibration test that can stably excite 200 hertz (Hz) or more, but not limited to this, various hammers that can excite the natural vibration of the third-order mode of the PC sleeper. Can be used. For example, an inspection hammer for a concrete structure may be used as the hammer 210. The reason for using the tertiary mode will be described later.
The microphone 220 acquires ambient sounds. In particular, the microphone 220 acquires sound generated when the hammer 210 vibrates the PC sleeper. The microphone 220 transmits the acquired sound to the recording diagnostic device 100 as audio data.

The recording diagnostic device 100 records the sound acquired by the microphone 220. Then, the recording diagnostic device 100 analyzes the recorded sound to detect the third-order mode natural frequency of the PC sleeper, and determines the deterioration of the PC sleeper. The deterioration determination here is determination of presence or absence of deterioration. Further, the detection of the third-order mode natural frequency here means obtaining an estimated value of the third-order mode natural frequency.
Note that the recording diagnostic device 100 may determine the degree of PC sleeper deterioration instead of or in addition to the presence or absence of PC sleeper deterioration.
The recording diagnostic device 100 is configured using, for example, a portable computer. Since the recording diagnostic device 100 is configured to be portable, a track maintenance and inspection worker can easily check sleepers using the recording diagnostic device 100 on site.

The strap 11 is provided so that the microphone 220 can be suspended from a person. Specifically, a maintenance inspection worker hangs the strap 11 around the neck and suspends the main body device 10 including the microphone 220 to the front of the body. Thereby, the maintenance / inspection worker can perform the deterioration determination using the PC sleeper deterioration determination system 1 without the need to perform the installation work of the main body device 10.
However, the position of the microphone 220 is not limited to the position suspended from the neck of the maintenance / inspection worker, and is generated when the hammer 210 vibrates to the PC sleeper, for example, within 1 meter (m) from the PC sleeper. Any position where sound can be acquired may be used. For example, the main body device 10 including the microphone 220 may be fixed by a belt at the waist position of the maintenance inspection worker.

The hammer 210 and the recording diagnostic device 100 may perform wireless communication.
Further, the recording diagnostic device 100 and the microphone 220 may not be integrated. For example, the recording diagnostic device 100, the hammer 210, and the microphone 220 may be configured as separate devices, and each of the hammer 210 and the microphone 220 may perform wireless communication with the recording diagnostic device 100. In this case, it is not necessary for a maintenance inspection worker to wear the recording diagnostic device 100. For example, a program may be installed in a general-purpose notebook computer (Laptop Computer) so as to function as the recording diagnostic device 100 and placed near the track to be inspected.

FIG. 2 is a schematic block diagram showing a functional configuration of the PC sleeper deterioration determination system 1. In the figure, the main body device 10 and the hammer 210 of the PC sleeper deterioration determination system 1 are shown. The main device 10 includes a recording diagnostic device 100 and a microphone 220. The recording diagnostic device 100 includes a display unit 110, a storage unit 180, and a control unit 190. The control unit 190 includes a natural frequency detection unit 191 and a deterioration determination unit 192.
2, parts having the same functions corresponding to the respective parts in FIG. 1 are denoted by the same reference numerals (1, 10, 100, 210, 220), and description thereof is omitted.

The display unit 110 has a display screen such as a liquid crystal panel, and displays various images. In particular, the display unit 110 displays the PC sleeper deterioration determination result.
The storage unit 180 is configured using a storage device included in the recording diagnostic device 100 and stores various data. In particular, the storage unit 180 stores audio data transmitted by the microphone 220 and a threshold value that serves as a criterion for deterioration determination.

The control unit 190 controls each unit of the recording diagnostic device 100 to execute various functions. The control unit 190 is realized by, for example, a CPU (Central Processing Unit) included in the recording diagnostic device 100 reading out a program from the storage unit 180 and executing it.
The natural frequency detection unit 191 analyzes the sound acquired by the microphone 220 and detects the natural frequency of the third-order bending mode of the PC sleeper. Specifically, the natural frequency detection unit 191 calculates an acceleration obtained by dividing the Fourier spectrum of the sound acquired by the microphone 220 by the excitation force measured by the acceleration sensor of the hammer 210. Then, the natural frequency detection unit 191 detects the natural frequency of the deflection tertiary mode from the obtained acceleration.
Note that the natural frequency detection unit 191 may detect the natural frequency of the bending third-order mode from the Fourier spectrum of sound instead of the acceleration. In this case, the hammer 210 does not need to measure the excitation force, and therefore may not have an acceleration sensor.

The deterioration determination unit 192 determines whether or not the PC sleeper has deteriorated based on whether or not the natural frequency of the deflection tertiary mode detected by the natural frequency detection unit 191 is lower than a predetermined condition. . More specifically, when determining that the natural frequency is lower than the predetermined condition, the deterioration determining unit 192 determines that the PC sleeper has deteriorated.
For example, the deterioration determination unit 192 performs determination using a natural frequency of a predetermined ratio (for example, 5 percent (%)) from the low frequency side as a threshold value among the natural frequencies of the plurality of PC sleeper deflection third modes. When the deterioration determination unit 192 determines that the natural frequency of the deflection tertiary mode detected by the natural frequency detection unit 191 is lower than the threshold value, the deterioration determination unit 192 determines that the PC sleeper to be determined is deteriorated. To do.

Next, an example of the excitation position value by the hammer 210 will be described with reference to FIGS.
FIG. 3 is an explanatory diagram showing the vibration position of the hammer 210 in a view of the PC sleeper as viewed from above. In the example of the figure, the hammer 210 struck and vibrates near the center of the PC sleeper. This is because it has been found by experiments that it is easy to excite the natural vibration of the third-order mode of the PC sleeper by applying vibration near the center of the PC sleeper as in the example of FIG.

FIG. 4 is an explanatory diagram showing the excitation position by the hammer 210 in a view of the PC sleeper from the side. In FIG. 4, the position described with reference to FIG. 3 is shown from another angle. As described with reference to FIG. 3, the hammer 210 struck and vibrates near the center of the PC sleeper.
The vibration position by the hammer 210 does not have to be exactly in the center of the PC sleeper, and may be in the vicinity of the center of the PC sleeper.

Further, the vibration position by the hammer 210 may be a position other than the vicinity of the center of the PC sleeper shown in FIGS. 3 and 4. For example, the hammer 210 may vibrate the PC sleeper outside the rail and in the vicinity of the rail.
Depending on the excitation position, the detection accuracy of the natural frequency of the tertiary mode may be lowered. In this case, for example, the presence or absence of PC sleeper deterioration may be determined for each excitation, and the final determination result of the presence or absence of PC sleeper deterioration may be determined by majority vote.

Next, with reference to FIGS. 5 to 8, the natural frequency of the bending tertiary mode detected by the natural frequency detection unit 191 will be described.
FIG. 5 is a graph showing an example of a change in natural frequency due to deterioration of PC sleepers. In the figure, the horizontal axis indicates the bending rigidity, and the vertical axis indicates the natural frequency. In FIG. 5, the natural frequency when the bending stiffness is 1 (reference value) when the fluctuation rate of each natural frequency in the vertical direction as the rigid body, the rotation as the rigid body, and the first-order bending to fifth-order bending mode is 1. It is shown.
The elastic modulus (Young's modulus) is E, the second moment of section is I, and the bending rigidity is EI.

  Among the natural frequencies shown in FIG. 5, the natural frequencies of the second-order bending mode to the fifth-order bending mode greatly change according to the change in bending rigidity. Therefore, when a deterioration such as cracking or wear occurs in a PC sleeper, a change in bending stiffness due to the deterioration can be detected by measuring one of the natural frequencies of the second-order bending mode to the fifth-order bending mode. Can be considered.

FIG. 6 is an explanatory diagram showing an example of the magnitude of vibration at each position of the PC sleeper due to the bending third mode natural vibration.
In the same figure, line L11 is explanatory drawing which shows the example of the waveform of a bending | flexion tertiary mode natural vibration. As indicated by line L11, the vicinity of the PC sleeper rail portion (position where the rail is laid) and the vicinity of the center are antinode positions in the deflection third-order mode natural vibration.

Regions A11 and A12 are regions where cracks are likely to occur.
The region A11 is a region on the bottom surface of the rail portion, and the region A12 is a region on the center upper surface. As the railcar passes on the rail, a load is applied to the rail portion. As a result, the region A11 may bend upward (convex downward) and cracks may occur due to positive bending (downward convex bending).

In addition, since both the left and right regions A11 bend upward, the region A12 located in the middle may bend downward (convex upward), and cracking may occur due to negative bending (convex upward bending).
It is conceivable that the frequency of the vibration changes due to deformation such as cracks in the vicinity of the vibration waveform. In this respect, it is considered that the natural frequency of the third mode is suitable for detecting deterioration of the PC sleeper due to the railcar passing through the rail.

FIG. 7 is a graph showing an example of changes in the natural frequency due to changes in the support force of the ballast roadbed or the roadbed. The horizontal axis of the figure shows the support force for PC sleepers by the ballast roadbed and the roadbed. The vertical axis represents the natural frequency. In FIG. 7, the natural frequency when the support force is 1 (reference value) is 1 when the fluctuation rate of each natural frequency in the vertical direction as the rigid body, the rotation as the rigid body, and the first-order deflection to fifth-order deflection mode is 1. It is shown.
Moreover, area | region A21 shows the range normally assumed as a support force with respect to PC sleeper by a ballast roadbed and a roadbed.

  In FIG. 7, the variation of the flexural third-order mode natural frequency is −0.9% to 1.5% in the range of the region A21. As described above, the influence of the change in the supporting force with respect to the PC sleeper by the ballast roadbed and the roadbed has a small influence on the fluctuation of the deflection third-order mode natural frequency. Accordingly, the deterioration determination unit 192 may perform a deterioration determination using the deflection third-order mode natural frequency, so that a change in the supporting force with respect to the PC sleeper caused by the ballast roadbed and the roadbed may be erroneously determined as the deterioration of the PC sleeper. Can be lowered.

  FIG. 8 is a graph showing an example of a change in natural frequency due to a change in both-end support force with respect to a PC sleeper. The horizontal axis of the figure shows the both-end support force for PC sleepers. The vertical axis represents the natural frequency. In FIG. 8, the fluctuation rate of each natural frequency in the vertical direction as a rigid body, the rotation as a rigid body, and the first-order deflection to fifth-order deflection mode is characteristic when the both-end support force for PC sleepers is 1 (reference value). The frequency is shown as 1.

  As shown in the figure, the influence of the both-end support force on the PC sleeper has little influence on the fluctuation of the deflection third-order mode natural frequency. Therefore, the deterioration determination unit 192 performs the deterioration determination using the deflection tertiary mode natural frequency, thereby reducing the possibility that the fluctuation of the both-end support force with respect to the PC sleeper is erroneously determined as the deterioration of the PC sleeper. be able to.

Next, the operation of the PC sleeper deterioration determination system 1 will be described with reference to FIGS.
FIG. 9 is a flowchart illustrating an example of a procedure of processing performed by the PC sleeper deterioration determination system 1. In the process of FIG. 9, the hammer 210 vibrates the PC sleeper, and the microphone 220 acquires the sound generated by the vibration (step S101). Specifically, a user (for example, a track maintenance / inspection worker) uses a hammer 210 to hit a PC sleeper, and the microphone 220 acquires a sound for a predetermined time including a timing of hitting the PC sleeper.
The microphone 220 transmits the acquired sound to the recording diagnostic device 100 as audio data. Further, the hammer 210 transmits the excitation force to the recording diagnostic device 100. In the recording diagnostic device 100, the storage unit 180 stores voice data from the microphone 220 and excitation force data from the hammer 210.

Next, the natural frequency detection unit 191 detects the third-order mode natural frequency of the PC sleeper based on the sound acquired by the microphone 220 (step S102).
FIG. 10 is a flowchart illustrating an example of a processing procedure in which the natural frequency detection unit 191 detects a deflection tertiary mode natural frequency. The natural frequency detection unit 191 performs the process of FIG. 10 in step S102 of FIG.

In the process of FIG. 10, the natural frequency detection unit 191 cuts out a certain amount of time including sound due to vibration from the voice data stored in the storage unit 180 (step S <b> 201). For example, the natural frequency detection unit 191 includes the sound data acquired by the microphone 220 and the excitation force measured by the hammer 210 for 0.2 seconds from the time when the excitation force measured by the hammer 210 records the maximum amplitude. Cut out the data.
Hereinafter, the excitation force measured by the hammer 210 is simply referred to as “excitation force”.

Next, the natural frequency detection unit 191 calculates the Fourier spectrum of each of the excitation force and the sound cut out in step S201 (step S202). Then, the natural frequency detection unit 191 determines the acceleration by dividing the Fourier spectrum of the sound by the Fourier spectrum of the excitation force (step S203).
Further, the natural frequency detection unit 191 cuts out a frequency band in which the natural frequency of the third-order bending mode of the PC sleeper is excited from the obtained acceleration (step S204). Specifically, the natural frequency detection unit 191 cuts out data in the range from 600 Hz to 1000 Hz in the tolerance.

Then, the natural frequency detection unit 191 renders the cut-out acceleration data dimensionless (step S205). Specifically, the natural frequency detection unit 191 performs normalization by dividing the cut-out data by the maximum value of the data.
Then, the natural frequency detection unit 191 detects the frequency (frequency) at which the acceleration is 1 (maximum value) as the natural frequency of the deflection tertiary mode (step S206).
Thereafter, the processing of FIG. 10 is terminated and the processing returns to FIG.

  Note that the natural frequency detection unit 191 may detect the natural frequency of the bending third-order mode from the Fourier spectrum of the sound instead of the acceleration. In this case, the process for the excitation force in steps S201 and S202 and the process in step S203 are unnecessary. In steps S204 to S206, “acceleration” is read as “Fourier spectrum of sound”.

Returning to FIG. 9, after step S102, the natural frequency detection unit 191 determines whether or not the processes of steps S101 and S102 have been repeated a predetermined number of times (step S103). For example, the natural frequency detection unit 191 determines whether or not the processes of steps S101 and S102 have been executed twice.
When it is determined that the predetermined number of repetitions of the processes of steps S101 and S102 have not been completed (step S103: NO), the process returns to step S101 and repeats.

On the other hand, when it is determined that the repetition is completed (step S103: YES), the natural frequency detection unit 191 calculates an average value of a plurality of natural frequencies obtained by the repetition and identifies the PC sleeper. The identification information (ID) is stored in the storage unit 180 (step S104). For example, kilometer or sleeper number can be used as PC sleeper identification information.
And the deterioration determination part 192 performs deterioration determination of PC sleeper based on the obtained natural frequency (step S105).

FIG. 11 is an explanatory diagram illustrating a first example of a processing procedure in which the deterioration determination unit 192 performs PC sleep deterioration determination. The degradation determination unit 192 performs the process of FIG. 11 in step S105 of FIG.
In the process of FIG. 11, the deterioration determination unit 192 determines whether or not the average value calculated by the natural frequency detection unit 191 is smaller than a predetermined threshold (step S301).

  When the PC sleeper deterioration diagnosis database is constructed, the threshold value is determined based on the natural frequency of other PC sleepers. For example, in step S301, the deterioration determination unit 192 determines whether or not it is included in the lower five percents in the database. This 5 percent is a value based on an empirical rule that the proportion of PC sleepers that have deteriorated is about 5 percent.

When it determines with an average value being more than a threshold value (step S301: NO), the process of FIG. 11 is complete | finished and the process of FIG. 9 is also complete | finished.
On the other hand, when it determines with an average value being smaller than a threshold value (step S301: YES), the display part 110 displays an important monitoring alarm (step S302). The important monitoring alarm here is an alarm indicating that there is a possibility that the target PC sleeper has deteriorated and monitoring is necessary.
After step S302, the process in FIG. 11 is terminated, and the process in FIG. 9 is also terminated.

In addition, it is good also considering not only one PC sleeper but a group of PC sleepers as an important monitoring object. Specifically, a group of PC sleepers on the same route as a PC sleeper for which an important monitoring alarm has been issued, or a group of PC sleepers of the same manufacturing patch is set as an important monitoring target.
When targeting routes, understand the impact of environmental factors such as the ground, passing tonnage, and rainfall. In addition, when manufacturing patches are targeted, the influence of the concrete material at the time of manufacturing is grasped. Similar PC sleepers are set as important monitoring targets.
This is based on an empirical rule that there is a relatively high possibility that a similar abnormality will occur at a location similar to a PC sleeper in which an abnormality has been confirmed in the past.
The PC sleeper deterioration diagnosis database may be shared by a plurality of PC sleeper deterioration determination systems, or may be provided for each PC sleeper deterioration determination system.

  When the deterioration diagnosis database for PC sleepers has not been constructed, it is conceivable that the deterioration determination unit 192 performs determination using a threshold value set based on the natural frequency of the sound third-order bending mode of PC sleepers. In this case, if the deterioration determination unit 192 determines that the natural frequency of the deflection tertiary mode detected by the natural frequency detection unit 191 is lower than the threshold, the PC sleeper to be determined is deteriorated. It is determined that

FIG. 12 is an explanatory diagram illustrating a second example of a processing procedure in which the deterioration determination unit 192 performs PC sleep deterioration determination. The degradation determination unit 192 performs the process of FIG. 12 instead of the process of FIG. 11 in step S105 of FIG.
In the process of FIG. 12, the deterioration determination unit 192 determines whether or not the average value calculated by the natural frequency detection unit 191 is smaller than a predetermined first threshold value (step S401). The first threshold is set to 85% of the natural frequency of a healthy PC sleeper, for example.

When it is determined that the average value is smaller than the first threshold value (step S401: YES), the display unit 110 displays a serious deterioration alarm (step S402). Thereafter, the process of FIG. 12 is terminated, and the process of FIG. 9 is also terminated.
The alarm of occurrence of serious deterioration is an alarm indicating the possibility of occurrence of serious deterioration, for example, a crack may reach the reinforcing bar.

  On the other hand, when it is determined in step S401 that the average value is greater than or equal to the first threshold value (step S401: NO), the deterioration determination unit 192 determines whether or not the average value is smaller than a predetermined second threshold value (step S403). ). The second threshold is a threshold larger than the first threshold, and is set to 95% of the natural frequency of a healthy PC sleeper, for example.

When it is determined that the average value is smaller than the second threshold (step S403: YES), the display unit 110 displays an alarm indicating the occurrence of deterioration (step S404). The deterioration occurrence alarm is an alarm indicating that there is a possibility that a slight deterioration has occurred rather than a serious deterioration occurrence alarm.
After step S404, the process in FIG. 12 is terminated, and the process in FIG. 9 is also terminated.
On the other hand, when it determines with an average value being more than a 2nd threshold value in step S403 (step S403: NO), the process of FIG. 12 is complete | finished and the process of FIG. 9 is also complete | finished.
At the end of the regular walking inspection of the track, the average values of the natural frequencies of all the PC sleepers recorded in the inspection may be sorted in descending order and output as the ranking of the deterioration state.

As described above, the microphone 220 acquires the sound generated by the excitation to the PC sleeper. Then, the natural frequency detection unit 191 detects the natural frequency of the third-order bending mode of the PC sleeper based on the sound acquired by the microphone 220. If the deterioration determining unit 192 determines that the natural frequency of the deflection tertiary mode detected by the natural frequency detecting unit 191 is lower than the predetermined condition, the PC sleeper to be determined is deteriorated. judge.
Thereby, in the PC sleeper deterioration determination system 1, it is possible to determine the deterioration of the PC sleeper without relying on visual inspection, and in this respect, it is possible to more easily grasp the deterioration state of the PC sleeper.
In addition, in the PC sleeper deterioration determination system 1, since the microphone 220 acquires non-contact data acquisition of sound, preparation for placing the sensor in contact with the PC sleeper is unnecessary. In this respect, the burden on the user can be reduced, and determination can be performed in a short time. Moreover, the process of removing the sensor from the PC sleeper is unnecessary even after the diagnosis is completed. In this respect as well, the burden on the user can be reduced and the working time can be shortened.

In addition, the deterioration determination unit 192 uses the natural frequency of the plurality of PC sleeper deflection third-order modes as a threshold from the low frequency side, and the deflection 3 detected by the natural frequency detection unit 191. If it is determined that the natural frequency of the next mode is lower than the threshold, it is determined that the PC sleeper to be determined has deteriorated.
As a result, the PC sleeper deterioration determination system 1 can use a threshold value according to the performance in the maintenance check of the PC sleeper, such as performing deterioration determination using a threshold value corresponding to the ratio of the deteriorated PC sleeper. Thereby, it is possible to determine the deterioration of the PC sleeper more accurately.

In addition, the deterioration determination unit 192 has a lower natural frequency of the deflection tertiary mode detected by the natural frequency detection unit 191 than the threshold set based on the natural frequency of the deflection of the third order mode of the healthy PC sleeper. If it is determined that the frequency is a frequency, it is determined that the PC sleeper to be determined is deteriorated.
Thereby, in the PC sleeper deterioration determination system 1, the user can set the threshold value relatively easily with reference to sound PC sleepers.

Moreover, the strap 11 which can hang the microphone 220 from a person is provided.
A user who checks a PC sleeper can place the microphone 220 near the PC sleeper by using the PC sleeper deterioration determination system 1 while the microphone 220 is suspended using the strap. In this respect, the user can easily use the PC sleeper deterioration determination system 1. Further, since the microphone 220 is positioned near the PC sleeper, the determination accuracy of the PC sleeper deterioration determination system 1 can be increased.

Next, an example of PC sleeper deterioration diagnosis by the method of the present embodiment will be described with reference to FIGS. First, with reference to FIG. 13, a comparative example between the third-order mode natural frequency of a cracked sleeper and the third-order mode natural frequency of a sound sleeper will be described.
FIG. 13 is a graph showing a detection example of the deflection third-order mode natural frequency of the pretension PC sleeper by sound analysis. In the figure, the sleeper 1 and the sleeper 2 are both PC sleepers having cracks on the lower surface of the rail portion. A rail part here is a part in which a rail is installed.
On the other hand, sleepers 3 to 5 are all healthy sleepers. A healthy sleeper here is a sleeper that has not deteriorated such as cracks.

  FIG. 13 shows the result of measuring the natural frequency of the third-order deflection mode for each sleeper three times. The third-order mode natural frequency of the PC sleeper having cracks on the lower surface of the rail portion is about 50 hertz (Hz) smaller than the third-order mode natural frequency of a sound PC sleeper.

Next, with reference to FIGS. 14-15, the example of the change of the 3rd mode natural frequency in a loading test is demonstrated.
FIG. 14 is an explanatory diagram showing a load position in the loading test. In the figure, a line CL indicates the center position of the PC sleeper.
As shown in FIG. 14, a pad 901 is placed on the rail portion on the upper surface of the PC sleeper, a loading plate 902 is placed on the pad 901, and a load receiver 903 is placed on the loading plate 902. Further, on the lower surface of the PC sleeper, the PC sleeper is supported at a load position (a position where the pad 901 is placed) at a position 350 mm (mm) away from each of the end side and the center side of the PC sleeper.

In this state, load loading, unloading, and measurement from the upper side of the load receiver 903 were repeated, and changes in the three-dimensional natural frequency were observed while gradually damaging the PC sleeper. In the measurement, the three-dimensional natural frequency of the PC sleeper was obtained from the spectrum.
The test was conducted according to JIS E 1201 and JIS E 1202.

FIG. 15 is a graph showing measurement results of the third-order mode natural frequency in the loading test. In the figure, the horizontal axis represents the loaded load, and the vertical axis represents the third-order mode natural frequency obtained by performing measurement in the unloaded state.
At 150 kilonewtons (kN) or more, large cracks are observed in the cross section of the rail portion, and the third-order mode natural frequency also decreases as the loading load increases. The third-order mode natural frequency is reduced by about 50 Hz at the maximum, which is consistent with the data shown in FIG.

Next, a comparison result between the deterioration determination using the microphone and the deterioration determination using the acceleration sensor will be described with reference to FIGS.
FIG. 16 is a schematic external view showing an example of the external shape of a PC sleeper deterioration determination system having an acceleration sensor.
In the figure, a hammer 210, a main body device 300, and an acceleration sensor 320 of the PC sleeper deterioration determination system 2 are shown. When the hammer 210 vibrates the PC sleeper with the acceleration sensor 320 installed in the PC sleeper, the main body device 300 determines the third-order mode natural frequency of the PC sleeper from the frequency spectrum of the acceleration detected by the acceleration sensor 320. Ask for.

FIG. 17 is an explanatory diagram illustrating an example of an installation position of the acceleration sensor 320. As shown in the figure, for example, the acceleration sensor 320 is installed near the rail portion closer to the center of the PC sleeper than the rail portion.
The installation of the acceleration sensor 320 may be performed, for example, by applying an adhesive between the acceleration sensor 320 and the PC sleeper or by applying silicon grease.

  When using an adhesive, it is necessary to wait for the adhesive to harden, whereas when using silicon grease, there is no need to wait for it to harden. In the case of using silicon grease, the time required for installing the acceleration sensor can be shortened in this respect. Furthermore, when using silicon grease, the acceleration sensor 320 can be removed from the PC sleeper more easily than when using an adhesive. When silicon grease is used, the time required for removing the acceleration sensor after the measurement can be shortened in this respect, and the burden on the operator can be reduced.

  However, in the method using a microphone in the present embodiment, it is not necessary to install an acceleration sensor or the like on the PC sleeper, and neither installation time nor removal time is required. In the method using the microphone in the present embodiment, the time required for determining the deterioration of the PC sleeper and the burden on the operator can be reduced in this respect.

FIG. 18 is an explanatory diagram showing an excitation position in a comparative test. The third-order mode natural frequency was measured several times for each of the case where the acceleration sensor was used and the case where the microphone was used when the outside of the rail portion of the PC sleeper was vibrated as in the vibration position 1 in FIG. . Similarly, the third-order mode natural frequency is measured several times for each of the case where the acceleration sensor is used and the case where the microphone is used. It was. The third-order mode natural frequency was measured several times for each of the case where the acceleration sensor was used and the case where the microphone was used.
In order to examine the degree of variation of the obtained third-order mode natural frequency for each excitation position, the average value of the obtained third-order mode natural frequency was obtained for each excitation position. The success rate was calculated with success within the average value ± 50 hertz and failure when the variation was larger than the average value ± 50 hertz.

FIG. 19 is a graph showing the detection success rate of the third-order mode natural frequency. When the acceleration sensor is used for each of the excitation positions 1, 2, and 3, the success rate is shown for each of the cases where the microphone is used. In the figure, A shows a case where an acceleration sensor is used, and B shows a case where a microphone is used.
In the vibration positions 2 and 3, when the acceleration sensor is used, a high success rate is obtained in both cases where the microphone is used. In particular, the vibration position 3 has a success rate of 100%. From this test result, it is considered that the variation in the natural frequency of the third-order mode obtained can be reduced by exciting the vicinity of the center of the PC sleeper (striking with the hammer 210).

FIG. 20 is a graph showing the third-order mode natural frequency obtained by exciting the vicinity of the center of the PC sleeper. Each of the 16 PC sleepers 1 to 16 is measured three times when using an acceleration sensor and when using a microphone, and the obtained natural frequency is shown in the graph.
As shown in the figure, in any measurement, the same result was obtained when the acceleration sensor was used and when the microphone was used. As described above, in the method using the microphone in the present embodiment, the third-order mode natural frequency can be obtained with high accuracy as in the case of using the acceleration sensor. By obtaining the tertiary mode natural frequency with high accuracy, the presence or absence of deterioration of the PC sleeper can be determined with high accuracy by the method using the microphone in the present embodiment.

It should be noted that a program for realizing all or part of the functions of the control unit 190 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed. You may perform the process of. Here, the “computer system” includes an OS and hardware such as peripheral devices.
Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.
The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 PC sleeper deterioration determination system 100 Recording diagnostic device 110 Display part 180 Memory | storage part 190 Control part 191 Natural frequency detection part 192 Deterioration determination part 210 Hammer 220 Microphone

Claims (4)

A microphone that obtains the sound generated by the vibration of the PC sleeper;
A strap capable of hanging the microphone from a person;
A natural frequency detector for detecting a natural frequency of the third-order bending mode of the PC sleeper based on the sound acquired by the microphone;
A deterioration determination unit that determines that the PC sleeper has deteriorated when it is determined that the natural frequency of the deflection tertiary mode detected by the natural frequency detection unit is lower than a predetermined condition;
PC sleeper deterioration judgment system.   The deterioration determining unit is configured to detect the third-order deflection detected by the first-order frequency detection unit using a predetermined ratio of the first-order natural frequency as a threshold value among the natural frequencies of the third-order bending mode of a plurality of PC sleepers. The PC sleeper deterioration determination system according to claim 1, wherein if the natural frequency of the mode is determined to be lower than the threshold value, it is determined that the PC sleeper to be determined is deteriorated.   The deterioration determination unit is configured such that the natural frequency of the deflection tertiary mode detected by the natural frequency detection unit is lower than a threshold set based on the natural frequency of the deflection third mode of healthy PC sleeper. The PC sleeper deterioration determination system according to claim 1, wherein it is determined that the PC sleeper to be determined is deteriorated. A sound collection step for acquiring sound generated by vibration to the PC sleeper with a microphone suspended from a person by a strap ;
A natural frequency detecting step of detecting a natural frequency of the third-order bending mode of the PC sleeper based on the sound acquired in the sound collecting step;
A deterioration determination step for determining that the PC sleeper has deteriorated when it is determined that the natural frequency of the deflection tertiary mode detected in the natural frequency detection step is lower than a predetermined condition;
PC sleeper deterioration determination method.