JP5114104B2 - Inspection method for inspecting the curing state of fiber reinforced plastic materials with buried pipes - Google Patents

Description

  The present invention relates to an inspection method for inspecting the cured state of a fiber-reinforced plastic material lined with an embedded pipe.

  As a typical method for repairing buried pipes such as sewage pipes, there is a construction method in which a fiber reinforced plastic material is repaired by sticking to the inner peripheral surface of the buried pipe. This method draws a tube-shaped fiber reinforced plastic material into the buried pipe, expands it by heating at the site, sticks it to the inner peripheral surface of the buried pipe, and further heat cures with heat, hot water, etc. Or by light curing to form an inner layer of fiber reinforced plastic material on the inner peripheral surface of the buried pipe (hereinafter referred to as fiber reinforced plastic material or other plastic material) Forming the inner layer on the peripheral surface is also called lining.)

  This method cures uncured fiber reinforced plastic material by chemically reacting it with heat or light in the field, so that the curing reaction is suppressed by insufficient heat or light irradiation or water that has entered the tube. As a result, there is a problem that the fiber-reinforced plastic material is not sufficiently cured.

  When such insufficient curing occurs, the strength of the buried pipe is insufficient, the resistance to external pressure is reduced, or the buried pipe is blocked by deformation of the fiber reinforced plastic material itself. There was a risk of adverse effects.

  Therefore, after repairing the buried pipe with fiber reinforced plastic, in order to inspect whether the fiber reinforced plastic is completely cured, a TV camera or the like is inserted into the buried pipe, and the lined buried pipe is The inside was imaged and the cured state of the fiber reinforced plastic material was confirmed.

  However, in such a conventional method, although the state of the surface of the fiber reinforced plastic material can be inspected, it has not been possible to confirm the internal cured state. Therefore, there has been a demand for a method that can reliably inspect the cured state of the fiber-reinforced plastic material.

  Therefore, as a method for inspecting the degree of curing of such a fiber-reinforced plastic material, for example, it is conceivable to apply the technique described in Patent Document 1.

The technique according to Patent Document 1 examines the degree of cure by examining the color tone based on the correlation graph between the color tone and the hardness on the surface of the cured resin. According to the present technology, it is considered that the degree of cure can be inspected by measuring the color tone of the fiber reinforced plastic material.
JP 06-041312 A

  However, when the technique described in Patent Document 1 is applied to a large cured product such as a fiber reinforced plastic material that lines the entire inner peripheral surface of the buried pipe, the fiber reinforced plastic material is sufficiently cured as a whole. In order to confirm whether or not it is necessary, it is necessary to inspect the color tone at a number of locations, which takes time.

This invention is made | formed in view of such a condition, and it aims at providing the inspection method which can test | inspect easily the hardening state of resin which lined the internal peripheral surface of the buried pipe.

  The inspection method for inspecting the cured state of the fiber reinforced plastic material lining the buried pipe according to the present invention is a method for inspecting the cured state of the fiber reinforced plastic material lining the inner surface of the buried pipe, and is a standard used as an inspection standard. For each pipe of the buried pipe and the inspection target buried pipe to be inspected, the impact position to which impact is applied is determined, impact is applied to these impact positions, and vibration due to impact is measured at a measurement position separated from each impact position by a predetermined distance. Then, for the frequency spectrum obtained from this vibration, the ratio of the area of the predetermined high frequency range and the area of the range including the predetermined low frequency range is calculated as a cured value, and by comparing these cured values, the inspection object The hardened state of the buried pipe is determined.

  According to the present invention, since the vibration based on the elastic wave propagating through the entire buried pipe is measured, the state of the entire fiber reinforced plastic material lining the buried pipe can be grasped, so that the fiber reinforced plastic material can be obtained in a short time. The entire cured state can be evaluated.

In addition, since the ratio of the area of the predetermined high frequency range and the area of the range including the predetermined low frequency range in the frequency spectrum is calculated and set as the cured value, the cured state can be grasped as a numerical value, and embedded It is possible to quantitatively grasp the cured state of the fiber reinforced plastic material whose inner peripheral surface is lined.

  In addition, the hardening value calculated based on the elastic wave (vibration) due to impact is a value reflecting the internal state of the fiber reinforced plastic material lining the buried pipe, so that the fiber reinforced plastic material lining the buried pipe is Not only the appearance state but also the uncured state inside the fiber reinforced plastic material can be grasped.

  Further, in the inspection method for inspecting the cured state of the fiber reinforced plastic material lined with the buried pipe according to the present invention, the impact applied to the reference buried pipe and the buried pipe to be inspected is an impact formed of iron, stainless steel or plastic It is good also as generating by the striking instrument provided with the part.

  In this case, a significant frequency spectrum can be generated in a frequency range where the difference in the cured state of the plastic material can be noticed by using a striking instrument having a striking portion formed of a material such as iron, stainless steel or plastic. Therefore, the cured state of the plastic material can be grasped more reliably.

  According to the inspection method for inspecting the cured state of the fiber reinforced plastic material lined with the buried pipe according to the present invention, the vibration based on the elastic wave propagating through the entire buried pipe is measured, and therefore the fiber reinforced plastic with the buried pipe lined. Since the state of the whole material can be grasped, the hardening state of the whole fiber reinforced plastic material can be evaluated in a short time.

  In addition, since the ratio of the area of the predetermined high frequency range and the area of the range including the predetermined low frequency range in the frequency spectrum is calculated and set as the cured value, the cured state can be grasped as a numerical value, and embedded It is possible to quantitatively grasp the cured state of the fiber reinforced plastic material whose inner peripheral surface is lined.

  In addition, the hardening value calculated based on the elastic wave (vibration) due to impact is a value reflecting the internal state of the fiber reinforced plastic material lining the buried pipe, so that the fiber reinforced plastic material lining the buried pipe is Not only the appearance state but also the uncured state inside the fiber reinforced plastic material can be grasped.

  Further, according to the inspection method for inspecting the cured state of the fiber reinforced plastic material lined with the buried pipe according to the present invention, the plastic material can be obtained by using a striking instrument having a striking portion formed of iron, stainless steel or plastic. Since a significant frequency spectrum can be generated in a frequency range in which the difference in the cured state can be noticeable, the cured state of the plastic material can be grasped more reliably.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The inspection method for inspecting the cured state of the fiber reinforced plastic material lined with the buried pipe according to the present invention is applied to, for example, a reinforced concrete buried pipe used for a sewer pipe or an agricultural water pipe. When inspecting an embedded pipe by this inspection method, first, a reference embedded pipe as an inspection standard and an inspection target embedded pipe to be inspected are prepared.

  Next, with respect to the reference buried pipe used as the inspection standard, the cured value indicating the cured state of the fiber-reinforced plastic material lined with the buried pipe is measured by the following cured value measuring method. The hardening value of the reference buried pipe is a reference value for determining the hardening state of the fiber reinforced plastic material lined with the inspection target buried pipe to be inspected. Here, as the reference buried pipe, a normal pipe in which the fiber reinforced plastic material is completely cured is selected, which is the same kind, shape, and size of the buried pipe to be inspected.

  Next, the hardening value is measured by the hardening value measuring method for the inspection object buried pipe to be inspected.

  Next, the cured state of the fiber reinforced plastic material lining the inspection target buried pipe is determined by comparing the cured values of the two. If the hardening value of the buried pipe to be inspected is comparable to the hardening value of the reference buried pipe, it is judged that the hardening is sufficient, and if there is a difference in the hardening value, it is judged as uncured. Is done.

  The above-mentioned cured value measuring method is a method for obtaining a cured value indicating the cured state of the fiber reinforced plastic material lining the buried pipe. First, a striking position that gives impact to the buried pipe is determined, and a striking instrument is provided at this striking position. The vibration caused by the impact is measured at a measurement position separated by a predetermined distance from the striking position, a frequency spectrum is obtained from the vibration, and a predetermined high frequency range area and a predetermined low frequency range are obtained for this frequency spectrum. This is a method for obtaining a cured value by calculating a ratio with the area of the included range as a cured value.

  Next, the Example which measured the buried pipe | tube by the hardening value measuring method and computed the hardening value is demonstrated concretely.

  FIG. 1 is an explanatory diagram illustrating a state when an embedded pipe is measured by applying an inspection method for inspecting a cured state of a fiber-reinforced plastic material lined with an embedded pipe according to an embodiment of the present invention.

  First, the buried pipe 1 related to the measurement of the hardening value is laid down on the earth and sand 14 laid flat on the ground 15. The earth and sand 14 stably holds the buried pipe 1 and plays a role of confining the buried pipe 1 in the buried pipe 1 itself without propagating the impact applied to the buried pipe 1 to the ground 15. Thereby, when an impact is applied to the buried pipe 1, the influence of the reflected wave from the ground 15 can be eliminated, and a frequency spectrum based on the buried pipe 1 itself can be obtained.

  Next, a geophone for receiving an elastic wave is disposed at a measurement position spaced a predetermined distance from a striking position that gives an impact to the buried pipe 1. For example, when a position at a predetermined distance from the tube port 2 of the buried pipe 1 is set as the striking position, the geophone is arranged at a measurement position that is spaced a predetermined distance from the striking position in the extending direction of the buried pipe 1. FIG. 2 specifically illustrates the striking position and the placement position of the geophone.

  FIG. 2 is an explanatory view for explaining the striking position and the position of the geophone in the inspection method for inspecting the cured state of the fiber-reinforced plastic material lined with the buried pipe according to the embodiment of the present invention.

  In the present embodiment, an impact is applied to the inner peripheral surface 3 of the buried pipe 1 at a predetermined distance from the pipe port 2, and the elastic wave is received by disposing the geophone 22 at a predetermined distance from the impact position where the impact is applied. I am going to do that. On the inner peripheral surface 3 of the buried pipe 1, a cart 20 that can be remotely controlled was prepared for the placement of a shock absorber 22 that receives an impact and an elastic wave due to the impact. The carriage 20 has a vehicle width that can pass through the buried pipe 1, and an impact device 21 that can give an impact to the buried pipe 1 and an elastic wave due to the impact can be received on the back of the carriage 20. A geophone 22 is provided.

  The striking instrument 21 includes a main body portion and a striking portion that can emit light from the main body portion. The striking instrument 21 is supported by an arm that can be moved up and down on the back of the carriage 20 and can be fixed at a predetermined distance from the inner peripheral surface 3 of the buried pipe 1. An impact is given to the buried pipe 1 by causing the striking portion to collide with the inner peripheral surface 3 by a signal.

  As the striking portion, it is preferable to use one formed of a material such as iron, stainless steel or plastic.

  In this case, by using the striking instrument 21 having a striking portion formed of iron, stainless steel, or plastic, a significant frequency spectrum is generated in a frequency range in which the difference in the cured state of the plastic material can be noticed. Therefore, the cured state of the plastic material can be grasped more reliably. For example, a frequency spectrum can be obtained in a frequency range of 0 to 5 kHz by using a striking portion formed of iron, stainless steel, or plastic.

  As the geophone 22, for example, a vibration sensor such as an acceleration sensor or an AE sensor (Acoustic Emission Sensor) is used.

Further, the geophone 22 is supported by an arm that can move up and down on the back of the carriage 20 and can be arranged at a measurement position that is spaced a predetermined distance from a striking position that strikes. In FIG. 2, by using the carriage 20, the five hitting positions (a, b, c, d, and e in the figure) that are 200 mm apart from the pipe port 2 are positioned 750 mm away from the respective hitting positions. The state which arrange | positions the geophone 22 is shown.

In the present embodiment, a configuration is shown in which a shock is applied to the buried pipe 1 by a remotely-controllable carriage 20 and vibration received by the shock is received by the geophone 22. However, this is a method of giving impact and a method of receiving vibration. It is not limited to.

For example, the method of giving an impact is not limited to the method of giving a hit with the remotely controlled hitting instrument 21 as shown in FIG. 2, but the impact may be given to the buried pipe 1 by dropping a steel ball or hitting with a hammer. Further, the striking position may be the outer peripheral surface of the buried pipe 1 or an impact may be applied from the outside of the buried pipe 1.

  For example, as a method of applying an impact, when an impact is applied by dropping a steel ball, the impact force is set to a constant value by dropping the steel ball from a predetermined height. In addition, when impact is applied by a hammer, the hammer is supported by an elastic body such as a spring, and the elastic body is stretched or stretched by a certain length to release the stored elastic force, thereby reducing the impact force to a constant value. As shock. Further, the impact force actually applied to the buried pipe 1 may be acquired as numerical data by using a commercially available impulse hammer. According to the impulse hammer, the impact force can be measured as numerical data, and the value can be reflected at the time of analysis.

  As a method of receiving vibration, the vibration receiver 22 may be fixed to the buried pipe 1 with a tape or an adhesive. In addition, when fixing to a place where a pressing jig or the like cannot be used because it cannot be fixed with a tape or an adhesive, it may be simply pressed by hand. The geophone 22 is not limited to being fixed to the inner peripheral surface 3 of the embedded pipe 1, and may be fixed to the outer peripheral surface of the embedded pipe 1.

  In addition, when inspecting the hardening state of the buried pipe 1 that is actually used, since it may come into contact with water, acidic water, basic water, etc., the striking instrument 21 has excellent corrosion resistance such as stainless steel. It is desirable to use a material that is formed of a new material, and as the geophone 22, it is desirable to use a material in which a housing or the like is formed of a material having excellent corrosion resistance such as stainless steel and the internal circuit is protected. .

  Next, the elastic wave due to the impact is measured by the geophone 22. The elastic wave is measured by acquiring it as a vibration signature by the geophone 22 until a predetermined time elapses from the moment the impact is applied. If the vibration signature is weak, it may be amplified by an amplifier or the like.

  Next, the frequency spectrum of the buried pipe 1 to be measured is calculated from the vibration signature obtained by the geophone 22. Specifically, the vibration signature obtained by the geophone 22 is subjected to FFT (Fast Fourier Transform) processing to obtain a frequency spectrum.

  FIG. 3 is a spectrum diagram showing a frequency spectrum acquired by an inspection method for inspecting a cured state of a fiber-reinforced plastic material lined with an embedded pipe according to an embodiment of the present invention.

  The obtained frequency spectrum is divided into a frequency spectrum in a predetermined high frequency range and a frequency spectrum in a range including a predetermined low frequency range for analysis. Specifically, as shown in FIG. 3, when the frequency spectrum is obtained in the frequency range 0 to 5 kHz, the region R1 of 0.02 to 3 kHz as the frequency spectrum in the range including the low frequency range, and the frequency spectrum in the high frequency range As 1 to 3 kHz region R2. Here, the range of 0 to 0.02 Hz and the range of 3 to 5 kHz are excluded because the noise occurs in the elastic wave measurement in the 0 to 0.02 Hz region. This is because there is a possibility that an accurate analysis cannot be performed when it is included in the analysis, and since there is almost no intensity in the region of 3 to 5 kHz, the analysis is not affected even if not considered.

  Next, the hardening value of the buried pipe 1 related to the measurement is calculated from the frequency spectrum obtained by the geophone 22.

  In the present embodiment, the curing value is obtained as a ratio between the area for the frequency spectrum of the predetermined high frequency range R2 and the area for the frequency spectrum of the range R1 including the predetermined low frequency range. The calculation method is shown as equation (1) below.

Curing value = (Area for frequency spectrum of high frequency range R2)
/ (Area about frequency spectrum of range R1 including low frequency range) ... (1)
Since the frequency spectrum is based on the elastic wave propagating through the buried tube 1, when the elastic wave is affected by the cured state of the fiber reinforced plastic material 4 lining the buried tube 1, the frequency spectrum has an elastic wave. It is considered that the fiber-reinforced plastic material 4 lining the buried pipe 1 is affected by the cured state. That is, since the vibration state of the molecules constituting the fiber reinforced plastic material 4 differs depending on the cured state of the fiber reinforced plastic material, it is considered that the frequency region that is easily absorbed is different. Therefore, the frequency spectrum depends on the cured state of the fiber reinforced plastic material 4. It is thought that the intensity distributions of

  According to the experimental example shown below, the frequency intensity of the reference buried pipe having the sufficiently hardened fiber reinforced plastic material 4 appears smaller in the high frequency range than in the low frequency range. On the other hand, the spectral frequency of the buried pipe to be inspected having the fiber reinforced plastic material 4 that is not sufficiently cured appears much smaller in the high frequency range than in the low frequency range (FIGS. 6 and 7). reference). That is, the ratio between the spectral intensity in the low frequency range and the frequency spectral intensity in the high frequency range varies depending on the state of curing.

  Since the above equation (1) is to obtain the ratio between the area for the frequency spectrum in the predetermined high frequency range R2 and the area for the frequency spectrum in the range including the predetermined low frequency range R1, the equation (1) The value (high-frequency component ratio) calculated by is an index for evaluating the waveform of the frequency spectrum obtained by measurement.

  Therefore, by comparing the high-frequency component ratio calculated for the inspection target buried pipe with the high-frequency component ratio calculated for the reference buried pipe, the cured state of the fiber-reinforced plastic material 4 lining the inspection target buried pipe can be evaluated. Moreover, since a hardening state can be grasped | ascertained by making a hardening state into a numerical value (hardening value), the hardening state of the fiber reinforced plastic material 4 which lined the internal peripheral surface of the buried pipe can be grasped | ascertained quantitatively.

The method for calculating the hardening value is limited to obtaining the ratio of the area for the frequency spectrum of the predetermined high frequency range R2 and the area for the frequency spectrum of the range including the predetermined low frequency range R1 as described above. Not. That is, as a method for calculating the hardening value, a function that can evaluate the difference in intensity between the frequency spectrum in a predetermined high frequency range and the frequency spectrum in a range including a predetermined low frequency range may be used. It may be a value.

  As described above, according to the inspection method for inspecting the cured state of the fiber reinforced plastic material lined with the buried pipe according to the present invention, the vibration based on the elastic wave propagating throughout the buried pipe 1 is measured. Since the state of the entire lined fiber reinforced plastic material 4 can be grasped, the cured state of the entire fiber reinforced plastic material 4 can be evaluated in a short time.

  Moreover, since the hardening value calculated based on the elastic wave (vibration) due to the impact reflects the internal state of the fiber reinforced plastic material 4 lining the buried pipe 1, the fiber reinforcement lining the buried pipe 1 is used. Not only the appearance state of the plastic material 4 but also the uncured state inside the fiber reinforced plastic material 4 can be grasped.

<Experimental example>
Hereinafter, specific experimental examples will be described.

[Measurement target]
FIG. 4 is a cross-sectional view of a buried pipe to be measured in this experimental example, cut along a plane including an axis in the extension direction.

  As a buried pipe 1 to be measured, a fiber reinforced plastic material 4 is applied to the inner peripheral surface 3 of a reinforced concrete fume buried pipe having a nominal diameter (inner diameter) of 300 mm and a length of 2 m based on a type B standard of JIS A5373. A lining with a thickness of 6 mm was used.

FIG. 5 is a partially enlarged view in which the cross section of the pipe wall is enlarged in the part A shown in FIG. 4, and FIG. 5 (A) shows a reference buried pipe by completely curing the fiber reinforced plastic material whose inner peripheral surface is lined. FIG. 5 (B) is a partially enlarged view of a fiber reinforced plastic material whose inner peripheral surface is lined to be uncured and used as an inspection target buried pipe.
In order to obtain a correlation diagram between the high-frequency component ratio and the degree of cure of the lined fiber-reinforced plastic material, four levels of cure were prepared. In other words, the case is completely cured (curing degree 100%), the case where 20% uncured exists for the entire thickness (curing degree 80%), and the case where 40% uncured exists for the entire thickness Case (curing degree 60%), case where 60% uncured exists for the entire thickness (curing degree 60%).

  As a reference buried pipe, an outer surface film (for example, a laminated film of polyamide synthetic fiber film and polyethylene film) 6 is attached to the inner peripheral surface 3 of the buried pipe 1, and a fiber reinforced plastic material having a thickness of 7.5 mm is lined. A completely cured product was prepared.

As an embedded pipe to be inspected, an outer surface film 6 is attached to the inner peripheral surface 3 of the embedded pipe 1, and a fiber reinforced plastic material having a thickness corresponding to the uncured thickness is lined and the inner peripheral surface thereof is uncured. A boundary film 7 was affixed to the inner peripheral surface, and a fiber reinforced plastic material having a thickness corresponding to the uncured thickness was lined on the inner peripheral surface of the boundary film 7 and completely cured.
FIG. 5C shows the thicknesses of the cured part and the uncured part.

[Impact on buried pipes]
As described above, the shock is applied to the reference buried pipe or the inspection target buried pipe by moving the remotely controllable carriage 20 into the buried pipe 1 and placing it at a predetermined position. This was carried out by applying an impact to the inner peripheral surface 3 of the buried pipe 1 with an impulse hammer.

  Further, in this experimental example, hitting was performed at five locations (a, b, c, d, and e in FIG. 2) spaced 200 mm apart from the tube port 2, and measurement was performed at each position.

[Acoustic wave receiving method]
An acceleration sensor was used as the geophone 22 for receiving the elastic wave. Data acquired by the acceleration sensor was processed by a control unit mounted on the carriage 20 and transmitted to a personal computer arranged outside via a communication cable.

  In addition, as shown in FIG. 2, with respect to each hitting position, a geophone was placed at a position 750 mm apart, and vibration was measured at five locations.

[Measurement result]
6 is a frequency spectrum obtained by applying the hardening value measuring method according to the present invention to the reference buried pipe, and (A) to (E) are frequency spectra obtained for the hitting positions a to e in FIG. is there. FIG. 7 is a frequency spectrum obtained by applying the hardening value measuring method according to the present invention to the buried pipe to be inspected, and (A) to (E) are the frequencies obtained for the hit positions a to e in FIG. It is a spectrum.

FIG. 6 shows a frequency spectrum obtained by applying the hardening value measurement method to the reference buried pipe, and FIG. 7 shows a frequency spectrum obtained by applying the hardening value measurement method to the inspection target buried pipe. It is shown. The frequency spectrum shown in FIGS. 6 and 7 is obtained by FFT processing from the vibration signal measured by the geophone 22.

  (A)-(E) of each figure has shown each of the frequency spectrum obtained by the geophone about the impact position ae shown in FIG. 2, and measured 3 times about each impact position ae The frequency spectrum which shows the median value among three hardening values obtained as a result of performing is shown.

[Analysis result]
FIG. 8 is a table showing high-frequency component ratios of the reference buried pipe and the inspection target buried pipe obtained for each of the measurements for the hitting positions a to e shown in FIG. FIG. 9 is a graph showing the high frequency component ratios of the reference buried pipe and the inspection target buried pipe obtained for each of the measurements for the hitting positions a to e shown in FIG.

  The table of FIG. 8 shows the median value obtained as a result of measuring three times at each hitting position a to e for the reference buried pipe and the inspection target buried pipe. The graph of FIG. 9 is a graph created based on the median value of the high-frequency component ratio obtained as a result of measuring three times for each hitting position a to e.

  According to FIG. 9, the high frequency component ratio of the inspection target buried pipe in which the fiber reinforced plastic material 4 whose inner peripheral surface is lined is uncured is larger than that of the completely hardened reference buried pipe. Further, if the value of the high frequency component ratio is defined as shown in FIG. 10, the degree of curing can be inspected. That is, the cured state of the fiber reinforced plastic material 4 whose inner peripheral surface is lined can be grasped by comparing the cured value measured for the buried pipe to be inspected with the cured value of the reference buried pipe.

  Therefore, when inspecting the buried pipe 1 that is actually buried, the inner peripheral surface of the buried pipe to be inspected is lined by obtaining the hardening value of the reference buried pipe as a reference in advance. The cured state of the fiber-reinforced plastic material 4 can be determined.

It is explanatory drawing explaining the state when applying the test | inspection method which test | inspects the hardening state of the fiber reinforced plastic material which lined the buried pipe which concerns on embodiment of this invention, and measures a buried pipe. It is explanatory drawing explaining the striking position and the arrangement position of a geophone in the test | inspection method which test | inspects the hardening state of the fiber reinforced plastic material which lined the buried pipe which concerns on embodiment of this invention. It is a spectrum figure which shows the frequency spectrum acquired by the test | inspection method which test | inspects the hardening state of the fiber reinforced plastic material which lined the buried pipe which concerns on embodiment of this invention. It is sectional drawing which cut | disconnected the underground pipe | tube used as the object of a measurement in this experiment example by the surface containing the axis | shaft of the expansion | extension direction. FIG. 5A is a partially enlarged view in which a pipe wall cross section is enlarged in a portion A shown in FIG. 4, and FIG. 5A is a portion of a fiber reinforced plastic material whose inner peripheral surface is lined to be completely cured to form a reference buried pipe. FIG. 5 (B) is a partially enlarged view of a fiber reinforced plastic material whose inner peripheral surface is lined and uncured to obtain a buried pipe to be inspected. FIG. 5C describes the cured and uncured thickness. It is the frequency spectrum obtained by applying the hardening value measuring method according to the present invention to the reference buried pipe, and (A) to (E) are the frequency spectra obtained for the striking positions a to e in FIG. It is a frequency spectrum obtained by applying the hardening value measuring method according to the present invention to the inspection target buried pipe, and (A) to (E) are frequency spectra obtained for the hit positions a to e in FIG. It is the table | surface which showed the hardening value of the reference | standard embedment pipe | tube obtained about each of the measurement with respect to the impact positions ae shown in FIG. It is the graph which showed the hardening value of the reference | standard embedment pipe | tube obtained about each of the measurement with respect to the impact positions ae shown in FIG. It is the table | surface which showed the reference value for determining a hardening degree.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Buried pipe 2 Pipe port 3 Inner peripheral surface 4 Fiber reinforced plastic material 14 Earth and sand 15 Ground 21 Impact tool 22 Vibration receiving device

Claims (3)

In order to repair the buried pipe, it is a method for inspecting the cured state of the fiber-reinforced plastic material that is affixed to the inner surface of the buried pipe and cured by heat or light and lining the inner surface of the buried pipe. And
An impact is applied to each of the buried pipe lined with the fiber-reinforced plastic material and the reference buried pipe , the fiber-reinforced plastic material lined on the inner surface, which is completely cured, as an inspection standard. Determine the striking position, respectively, impact the striking position from the inner surface side where the fiber reinforced plastic material is lined ,
Measuring the vibrations caused by impact with a predetermined distance spaced measurement position from the respective striking position, the frequency spectrum obtained from the vibration, the area of the high-frequency range of the region of 1～3KHz, areas of 0.02~3kHz low Calculate the ratio with the area of the range including the frequency range as the curing value,
Inspecting a hardened condition of the fiber-reinforced plastic material of the buried pipe lined, characterized in that to determine the cured state of the fiber-reinforced plastic material which is lined on the inner surface of the front Kiuma設管by comparing these curing values between Inspection method to do. Shock given to the reference buried pipe and before Kiuma設管the fiber-reinforced plastic material which is lined on the inner surface of the is characterized by generating by striking instrument with iron, a striking part formed by stainless steel or plastic The inspection method which test | inspects the hardening state of the fiber reinforced plastic material which lined the buried pipe of Claim 1. Regarding the inspection of the cured state, calculate the ratio between the area of the high frequency range of the 1 to 3 kHz region and the area of the range including the low frequency range of the 0.02 to 3 kHz region and obtain the correlation with the degree of curing. The inspection method for inspecting the hardening state of the fiber-reinforced plastic material lined with the buried pipe according to claim 1, wherein the degree of hardening is estimated from the area ratio of the obtained frequency.

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