JP3848948B2 - Pipeline fluid leakage exploration system and exploration method - Google Patents

Description

  The present invention relates to a pipeline fluid leakage exploration system and a method for exploring the same, and more particularly, to a pipeline fluid leakage exploration system for exploring the position of water leakage occurring in a large-diameter underground pipeline such as an agricultural water utilization facility and the like. It relates to exploration methods.

  Agricultural waterways began to be pipelined in the 1960s, and in 1990, approximately 200,000 ha of water, 16% of the developed paddy fields, was pipelined. Since then, state-owned projects alone have increased the number of pipelines installed at a rate of 100 to 150 km per year. Pipelines buried in the early stages of maintenance have become obsolete and water leakage has become a problem in some areas. In addition, since the early pipeline design did not have enough countermeasures against earthquakes, there are places where there is a risk of water leakage due to deformation due to earthquake motion. Pipeline diameters used range from 150 mm to 300 mm. Up to now, there is no statistical data on the amount of water leakage from agricultural pipelines, but it is estimated that about 10% of water leakage occurs in consideration of examples such as waterworks. At the design stage, a 5% transport loss is expected, so if a loss of 5% or more occurs due to water leakage, the plan will be hindered. However, since the actual usage at the end cannot be grasped accurately, the measurement of water leakage cannot be evaluated by the water balance. When a leak location is discovered, a method is used to calculate from the scale, but the fact that the leak location cannot be detected is the reason why the actual leak location cannot be determined.

  Conventionally, as a method of exploring water leakage, in water leakage investigation of underground pipes for water supply (many diameters are 100 mm to 250 mm), a sounding rod connected to a water leakage detector is applied to the ground on the piping, and from the water leakage point to the ground There is known a method for detecting a water leak location by a transmitted water leak sound. Leakage sound is the sound that accompanies water that erupts vigorously from underground water pipes due to water pressure. (1) Flowing sound, (2) Impact sound, (3) Friction sound with pipe, (4) Pipe vibration It is a complex sound with four elements of sound. Since the water leaking sound combines conditions such as the occurrence of water leakage, soil quality, pipe type, water pressure, depth and the four elements, the water leaking sound does not have a constant frequency distribution. Therefore, the survey is conducted at midnight with little noise, and the investigator is required to have a skilled listening technology. Recently, there have been methods that do not rely on experience or intuition to combine the leaked sound with a combination of high and low frequency filters, or to determine the distance of the leaked position from the slight difference in arrival time of the leaked sound detected by the two leak detectors. It has been broken. However, it is a fact that the pseudo sound of water leakage due to car noise makes it difficult to identify the water leakage sound, and the final judgment must rely on many years of experience and intuition.

For this reason, conventionally, the following five methods are known for water leakage exploration of large-diameter pipelines. (1) Method of enclosing high-pressure gas and detecting leakage to the outside of the pipe, (2) Method of enclosing high-pressure air and detecting a pressure drop section, (3) Method of detecting leakage sound of water or encapsulated air (4) A method for measuring a potential difference between a pipe and the ground, and (5) a method for visualizing a dielectric constant distribution by an underground radar (for example, see Non-Patent Document 1).
Hiromasa Shima, Kazuhiko Sakuma, Hideki Kamiya, “Resistivity Imaging,” Kokon Shoin, March 3, 1995, p189-190

  However, the methods (1) and (2) are difficult to apply to a large-capacity large-diameter pipeline, and the resolution is low even if it is forcibly adopted. The method (3) can be applied in principle, but the hit rate is remarkably low in an actually implemented example. The method (4) is a principle that can be applied to damage of a coated pipe, but in reality, satisfactory results are rarely obtained by interference with artificial noise. The method (5) can be applied only when the ground is hollowed in the shallow area, and there is a limit to detecting the water leaking point of a large-diameter pipeline with a pipe diameter of 400 mm or more. In addition, when a large-diameter pipeline leaks water and a person enters the pipe and conducts a visual inspection, a fatal accident may occur due to a tunnel survey or inspection of sewers, manholes, old wells, water storage tanks, etc. As can be seen, there is a concern about an oxygen deficiency accident. In addition, when a water leak location is specified by an agricultural water supply pipeline with a pipe diameter of 400 mm to 900 mm, for example, humans cannot enter the pipe. For example, a small camera or fiberscope is introduced into the drained pipeline. , Workers can check visually on an external monitor. However, it is not possible to immediately identify a water leak point due to a flaw inside the pipeline, and it takes a lot of work time based on the experience and intuition of the worker whether the flaw leads to water leak. In addition, when water leaks due to minute scratches that cannot be grasped visually, there is a possibility of overlooking the water leak point.

  The present invention has been made to solve the above-described problems, and provides a pipeline fluid leak search system and a search method thereof that can easily and reliably find a fluid leak location in a pipeline with a simple configuration. It is intended to do.

The pipeline fluid leakage exploration system according to the present invention is a pipeline fluid leakage exploration system embedded in the underground and in which a fluid circulates. The traveling means is disposed in the pipeline from which the fluid is discharged, and the traveling means is radioactive. Thermal neutron measurement means for measuring thermal neutrons emitted from the radiation source and respectively passing through the soil above and below the pipeline are provided, and the travel of the travel means is controlled to control the thermal neutron measurement positions on the pipeline and the corresponding positions. It is equipped with a central processing unit that calculates thermal neutron measurement data and identifies the fluid leak position in the pipeline , and the thermal neutron measurement means is installed in the upper center of the vehicle body so that it can be displaced vertically and passes through the soil above the pipeline. A neutron moisture meter for detecting upper moisture that measures thermal neutrons in the background, a pipeline inner surface and a predetermined And a pair of lower moisture detection neutron moisture meters, each of which is provided at a distance and measures thermal neutrons that have passed through the soil below the pipeline. An increase / decrease pattern detection means for obtaining an increase / decrease pattern based on each measured value and the same increase / decrease pattern by comparing the increase / decrease pattern for the neutron moisture meter for detecting both lower moisture detected by the increase / decrease pattern detection means for each measurement time The same pattern extraction means for extracting the measurement times of the same pattern, and the measurement times of the same pattern extracted by the same pattern extraction means to further extract the measurement times in which the same pattern continuously appears a predetermined number of times. The position on the pipeline corresponding to the measurement round is identified, and the identified position is regarded as an increase in moisture and is determined to be a leak point. The filtering means and a judging means is provided, in which so as to remove the noise component of the background according to the specifications of the pipeline.

In the pipeline fluid leakage exploration system according to the present invention, in the pipeline fluid leakage exploration system embedded in the underground and through which the fluid flows, traveling means is disposed in the pipeline from which the fluid has been discharged, and the traveling means is radioactive. Thermal neutron measurement means for measuring thermal neutrons emitted from the radiation source and respectively passing through the soil above and below the pipeline are provided, and the travel of the travel means is controlled to control the thermal neutron measurement positions on the pipeline and the corresponding positions. It is equipped with a central processing unit that calculates thermal neutron measurement data and identifies the fluid leak position in the pipeline, and the thermal neutron measurement means is installed in the upper center of the vehicle body so that it can be displaced vertically and passes through the soil above the pipeline. Neutron moisture meter for upper moisture detection to measure thermal neutrons in the background, pipeline inner surface and predetermined A pair of neutron moisture meters for detecting lower moisture that are respectively provided at intervals and measure thermal neutrons that have passed through the soil below the pipeline, and the central processing unit includes a neutron moisture meter for detecting lower moisture. An increase / decrease pattern detection means for obtaining an increase / decrease pattern based on each measured value and the same increase / decrease pattern by comparing the increase / decrease pattern for the neutron moisture meter for detecting both lower moisture detected by the increase / decrease pattern detection means for each measurement time The same pattern extraction means for extracting the measurement times of the same pattern, and the measurement times of the same pattern extracted by the same pattern extraction means to further extract the measurement times in which the same pattern continuously appears a predetermined number of times. Identifies the position on the pipeline corresponding to the measurement round, and regards the specified position as a water increase part and determines that it is a leak point That the filtering means and a judging means is provided, by which is adapted to remove the noise component of the background according to the specifications of the pipeline, the thermal neutron measuring means disposed in the pipeline, yet the traveling means Since the measurement is performed while traveling in the pipeline, the thermal neutron measurement means continuously measures the thermal neutrons that have passed through the soil above and below the pipeline while traveling at a predetermined speed. Then, the thermal neutron measurement position on the pipeline and the measurement data of each thermal neutron corresponding to the position are determined from the traveling speed and the traveling distance. For this reason, the position where the fluid component change increases is read from the combined value of the radioactivity variation and the fluid component change that occur randomly based on the determined data, and the fluid leakage position of the pipeline is specified. The neutron moisture meter for detecting the upper moisture is provided on the center of the upper part of the vehicle so that it can be displaced vertically, and the neutron moisture meter for detecting the lower moisture is provided at a predetermined distance from the inner surface of the pipeline. In addition, it is possible to suppress the generation of noise components due to friction without contacting the inner wall of the pipeline. Further, since the neutron moisture meter for detecting the upper moisture is provided on the center of the upper part of the vehicle body so as to be vertically displaceable, it can be used for pipelines having different pipe diameters. Furthermore, the pair of neutron moisture meters for detecting the lower moisture is provided on both the left and right sides of the lower part of the vehicle body, so even if sand mud is deposited on the bottom of the pipeline, it can be avoided. Also, the height of the background during burial differs depending on the pipeline specifications, that is, the pipe diameter, pipe thickness, and pipe material, even if the measured value of thermal neutrons captured by the neutron moisture meter for lower moisture detection is the upper moisture detection Even if it is hidden in the background captured by the neutron moisture meter for the neutron, the fluctuation of the radioactivity that occurs at random is also the random pattern of the neutron moisture meter for detecting both lower moisture, so the same part more than the number of times the variation pattern Is regarded as a variation portion of moisture change, and by performing a filtering process, a background noise component can be removed, and the location of water leakage can be accurately determined.

The pipeline fluid leakage exploration system according to claim 2 is a pipeline fluid leakage exploration system embedded in the underground and in which the fluid flows, and is disposed inside the pipeline from which the fluid is discharged, and receives a command signal from the outside. The traveling means whose drive is controlled based on the above and the thermal neutrons that are provided in the traveling means, have a radioactive radiation source, are emitted from the radiation source, and pass through the soil above and below the pipeline, are measured every predetermined time. Thermal neutron measurement means that outputs to the outside, travel distance measurement means that is provided in the travel means, measures the travel distance of the travel means and outputs to the outside, and is disposed on the ground, and the travel means is connected to the input means via the monitor. Thermal neutron measurement values and travel distances output from thermal neutron measurement means and travel distance measurement means, respectively, while operating freely at a constant travel speed Constant values and travel speed data of the travel means are input, these data are stored in the memory and processed, and the measurement position on the pipeline is determined from the travel speed and travel distance for each measurement of thermal neutrons. It is equipped with a central processing unit that obtains data on the thermal neutrons above and below the pipeline at the measurement position and identifies the fluid leakage position of the pipeline , and the thermal neutron measurement means can be displaced vertically in the center of the upper part of the vehicle body The upper moisture detection neutron moisture meter that measures the background thermal neutrons that have passed through the soil above the pipeline, and the pipeline inner surface with a predetermined distance on the left and right sides of the lower part of the vehicle body, respectively. And a pair of lower moisture detection neutron moisture meters that measure thermal neutrons that have passed through the soil below. The increase / decrease pattern detection means for obtaining the increase / decrease pattern based on the measurement values respectively measured by the neutron moisture meter for the measurement, and the increase / decrease pattern for the neutron moisture meter for detecting both lower moisture detected by the increase / decrease pattern detection means for each measurement time The same pattern extraction means for comparing and extracting the same increase / decrease pattern measurement times, and further extracting the measurement times for which the same pattern appears continuously a predetermined number of times from the same pattern extraction times extracted by the same pattern extraction means, these A filter processing means is provided that includes a determination means that identifies a position on the pipeline corresponding to the extracted continuous measurement times, and regards the identified position as a water increase portion and determines a water leak location. The background noise component is removed according to the specification .

In the pipeline fluid leakage exploration system according to claim 2, in the pipeline fluid leakage exploration system embedded in the underground and through which the fluid flows, the pipeline is disposed inside the pipeline from which the fluid is discharged, and is based on a command signal from the outside. A traveling means whose drive is controlled, and a thermal neutron provided in the traveling means, having a radioactive radiation source, emitted from the radiation source and passed through the soil above and below the pipeline, respectively, and measured outside at predetermined intervals. Thermal neutron measuring means for outputting, traveling distance measuring means provided on the traveling means for measuring the traveling distance of the traveling means and outputting to the outside, arranged on the ground, and freely allowing the traveling means through the monitor by the input means Operate and drive at a constant traveling speed, and measure thermal neutron values and mileage output from thermal neutron measurement means and mileage measurement means, respectively And travel speed data of the travel means are input, these data are stored in a memory and processed, and the measurement position on the pipeline is determined from the travel speed and travel distance for each measurement of thermal neutrons, and the measurement is performed. It has a central processing unit that obtains thermal neutron data above and below the pipeline at the location and identifies the fluid leakage position of the pipeline, and the thermal neutron measurement means is provided to be vertically displaceable in the center of the upper part of the vehicle body The upper moisture detection neutron moisture meter that measures the background thermal neutrons that have passed through the soil above the pipeline, and the pipeline inner surface with a predetermined distance on the left and right sides of the lower part of the vehicle body, respectively. And a pair of lower moisture detection neutron moisture meters that measure thermal neutrons that have passed through the soil. The increase / decrease pattern detection means for obtaining the increase / decrease pattern based on the measurement values measured by the sexual moisture meter, and the increase / decrease pattern for the neutron moisture meter for detecting both lower moisture detected by the increase / decrease pattern detection means are compared for each measurement. The same pattern extracting means for extracting measurement times of the same increase / decrease pattern and the measurement times where the same pattern appears continuously a predetermined number of times are extracted from the measurement times of the same pattern extracted by the same pattern extraction means, and these are extracted. The pipeline specification is provided with a filter processing means having a determination means for identifying a position on the pipeline corresponding to the consecutive measurement times and determining the identified position as a water leakage portion by regarding the identified position as an increased portion of moisture. The background noise component is removed according to the While continuously running in the inn, the thermal neutron measurement means continuously measures the thermal neutrons that have passed through the soil above and below the pipeline, and the travel distance measurement means measures the travel distance required for the thermal neutron measurement. These thermal neutron measurement data and travel distance measurement data are output to the central processing unit. When the travel speed and travel distance data are input to the central processing unit in addition to the input data, the measurement position on the pipeline for each measurement of thermal neutrons is determined. Based on the data of thermal neutrons above and below the pipeline at the measurement position, the position where the fluid component change increases is read from the combined value of the radioactivity fluctuation and fluid component change that occur at random. The fluid leakage position is identified. For this reason, a fluid leak location is specified reliably in real time. The neutron moisture meter for detecting the upper moisture is provided on the center of the upper part of the vehicle so that it can be displaced vertically, and the neutron moisture meter for detecting the lower moisture is provided at a predetermined distance from the inner surface of the pipeline. In addition, it is possible to suppress the generation of noise components due to friction without contacting the inner wall of the pipeline. Further, since the neutron moisture meter for detecting the upper moisture is provided on the center of the upper part of the vehicle body so as to be vertically displaceable, it can be used for pipelines having different pipe diameters. Furthermore, the pair of neutron moisture meters for detecting the lower moisture is provided on both the left and right sides of the lower part of the vehicle body, so even if sand mud is deposited on the bottom of the pipeline, it can be avoided. Also, the height of the background during burial differs depending on the pipeline specifications, that is, the pipe diameter, pipe thickness, and pipe material, even if the measured value of thermal neutrons captured by the neutron moisture meter for lower moisture detection is the upper moisture detection Even if it is hidden in the background captured by the neutron moisture meter for the neutron, the fluctuation of the radioactivity that occurs at random is also the random pattern of the neutron moisture meter for detecting both lower moisture, so the same part more than the number of times the variation pattern Is regarded as a variation portion of moisture change, and by performing a filtering process, a background noise component can be removed, and the location of water leakage can be accurately determined.

  Further, in the pipeline fluid leakage exploration system according to claim 3, the traveling means includes a vehicle body in which a plurality of chassis are connected to each other so as to be able to be bent, and is allowed to travel along substantially the center line of the pipeline. It is.

  In the pipeline fluid leakage search system according to the third aspect, the vehicle body bends even if the pipeline is bent. Therefore, the leakage location can be searched without being restricted by the installation shape of the pipeline.

In the pipeline fluid leakage exploration system according to claim 4 , the neutron moisture meter includes a radiation source that emits fast neutrons and a neutron counter that detects thermal neutrons in the casing, and the casing. In addition, an absorber that suppresses interference from other radiation sources and reduces neutron rays as noise components is provided.

In the pipeline fluid leakage exploration system according to the fourth aspect of the present invention, interference from other radiation sources can be suppressed by the absorber, and the neutron rays of noise components can be reduced, so that the accuracy is improved.

The pipeline fluid leakage exploration system according to claim 5 is characterized in that the filtering means detects moisture at both lower portions at each measurement time for the measurement times in which the same pattern extracted by the same pattern extraction means appears continuously a predetermined number of times. The measured values of the neutron moisture meter for use are totaled and statistically processed.

In the pipeline fluid leakage exploration system according to claim 5 , the statistically processed data includes the total of the measured values of the neutron moisture meters for detecting moisture at both lower portions. As the area with the highest possibility of water leakage is visually emphasized, the total measurement value is relatively lower compared to the area with high possibility of water leakage even though the presence of water components is recognized in the surrounding area. In addition, it is possible to pinpoint a portion having a high possibility of water leakage very accurately.

In the pipeline fluid leakage exploration system according to a sixth aspect of the present invention, the traveling means is provided with a photographing device that captures the state inside the pipeline and wirelessly transmits an image to an external monitor.

In the pipeline fluid leakage exploration system according to the sixth aspect , since the measurement can be performed while observing the inside of the pipeline with an external monitor, it is also possible to investigate a damaged portion that does not reach the water leakage.

In the pipeline fluid leakage exploration system according to claim 7 , the traveling means outputs the video signal from the imaging device and the data from the thermal neutron measurement means and the travel distance measurement means to the outside via radio, and externally. Is provided with a wireless communication section for sending a command signal from the traveling means to the control section of the traveling means, and this wireless communication section communicates with the outside through a transfer means disposed inside the pipeline.

In the pipeline fluid leakage exploration system according to the seventh aspect , the traveling means can be controlled on the ground through the image of the photographing apparatus, so that the work is made efficient. Further, since communication is made with the outside through the transfer means in the pipeline, the travel means can be traveled to a long distance and measurement can be performed, and a large amount of data can be obtained in a short time.

In the pipeline fluid leakage exploration method according to the present invention, a traveling means is disposed inside a pipeline buried in the underground and through which the fluid flows, and the pipeline is discharged from the radioactive ray source to the traveling means. Thermal neutron measurement means is provided to measure thermal neutrons that have passed through the upper and lower soils. The thermal neutron measurement means measures the thermal neutrons above and below the pipeline while the traveling means is traveling at a predetermined speed, and the traveling speed and traveling distance are measured. A pipeline fluid leakage exploration method for determining a fluid leakage position of a pipeline after determining a thermal neutron measurement position on the pipeline and data of each thermal neutron corresponding to the position from The thermal neutrons at the bottom of the pipeline are measured by the neutron moisture meter for detecting moisture at the left and right sides, respectively. After measuring the thermal neutrons at the top and bottom of the pipeline, obtain the increase / decrease pattern of the measurement value measured by each lower moisture detection neutron moisture meter, and measure the increase / decrease pattern for both lower moisture detection neutron moisture meters Compared to, extract the measurement times of the same increase / decrease pattern, further extract the measurement times that the same pattern appears continuously for a predetermined number of times from the extracted same pattern, and correspond to these extracted consecutive measurement times The position on the pipeline to be identified is identified, and the identified position is regarded as a portion where moisture has increased, and is determined to be a water leak location .

In the pipeline fluid leakage exploration method according to the present invention, a traveling means is disposed inside a pipeline buried in the underground and through which the fluid flows, and the pipeline is discharged from the radioactive ray source to the traveling means. Thermal neutron measurement means is provided to measure thermal neutrons that have passed through the upper and lower soils. The thermal neutron measurement means measures the thermal neutrons above and below the pipeline while the traveling means is traveling at a predetermined speed, and the traveling speed and traveling distance are measured. A pipeline fluid leakage exploration method for determining a fluid leakage position of a pipeline after determining a thermal neutron measurement position on the pipeline and data of each thermal neutron corresponding to the position from The thermal neutrons below the pipeline are measured by the lower moisture detection neutron moisture meters provided on the left and right sides of the direction, respectively. Next, after measuring the thermal neutrons above and below the pipeline, obtain the increase / decrease pattern of the measured values measured by each lower moisture detection neutron moisture meter, and measure the increase / decrease pattern for both lower moisture detection neutron moisture meters. Compared every time, extract the same increase / decrease pattern measurement times, and further extract the measurement times that the same pattern appears continuously a predetermined number of times from the extracted same pattern measurement times, to these extracted consecutive measurement times The corresponding position on the pipeline is identified, and the identified position is regarded as a water increase part and is determined as a leak point, so that the traveling means travels at a predetermined speed in the pipeline from which the fluid is discharged. While measuring the thermal neutrons that passed through the soil above and below the pipeline continuously and repeatedly using the thermal neutron measurement means, the measurement times, travel speed, and travel distance Thermal neutron measurement position on the pipeline and the respective thermal neutron data corresponding to the position is determined. After the data is determined, the position where the fluid component change increases is read from the combined value of the radioactivity fluctuation and the fluid component change which randomly occur based on the determined data, and the fluid leakage position of the pipeline is specified. Also, the height of the background during burial differs depending on the pipeline specifications, that is, the pipe diameter, pipe thickness, and pipe material, even if the measured value of thermal neutrons captured by the neutron moisture meter for lower moisture detection is the upper moisture detection Even if it is hidden in the background captured by the neutron moisture meter for the neutron, the fluctuation of the radioactivity that occurs at random is also the random pattern of the neutron moisture meter for detecting both lower moisture, so the same part more than the number of times the variation pattern Can be regarded as a fluctuation part of moisture change, background noise components can be removed, and the location of water leakage can be accurately determined.

Furthermore, in the pipeline fluid leakage exploration method according to claim 9 , the measured values of the neutron moisture meters for detecting moisture at both lower portions are measured at each measurement time for the measurement times in which the extracted same pattern appears continuously a predetermined number of times. After summing up, statistical processing is performed.

In the pipeline fluid leakage exploration method according to claim 9 , since the statistically processed data on the chart is the sum of the measured values of the neutron moisture meters for detecting moisture at both lower portions, In the surrounding area, the part with high possibility of water leakage is visually emphasized, and the surrounding area has a relatively total measurement value compared with the part with high possibility of water leakage even though the presence of water component is recognized. Because it is low, the location with high possibility of water leakage is pinpointed very accurately just by looking at the statistically processed chart.

In the pipeline fluid leakage exploration system according to the present invention, in the pipeline fluid leakage exploration system embedded in the underground and through which the fluid flows, traveling means is disposed in the pipeline from which the fluid has been discharged, and the traveling means is radioactive. Thermal neutron measurement means for measuring thermal neutrons emitted from the radiation source and respectively passing through the soil above and below the pipeline are provided, and the travel of the travel means is controlled to control the thermal neutron measurement positions on the pipeline and the corresponding positions. It is equipped with a central processing unit that calculates thermal neutron measurement data and identifies the fluid leak position in the pipeline , and the thermal neutron measurement means is installed in the upper center of the vehicle body so that it can be displaced vertically and passes through the soil above the pipeline. Neutron moisture meter for upper moisture detection to measure thermal neutrons in the background, pipeline inner surface and predetermined A pair of neutron moisture meters for detecting lower moisture that are respectively provided at intervals and measure thermal neutrons that have passed through the soil below the pipeline, and the central processing unit includes a neutron moisture meter for detecting lower moisture. An increase / decrease pattern detection means for obtaining an increase / decrease pattern based on each measured value and the same increase / decrease pattern by comparing the increase / decrease pattern for the neutron moisture meter for detecting both lower moisture detected by the increase / decrease pattern detection means for each measurement time The same pattern extraction means for extracting the measurement times of the same pattern, and the measurement times of the same pattern extracted by the same pattern extraction means to further extract the measurement times in which the same pattern continuously appears a predetermined number of times. Identifies the position on the pipeline corresponding to the measurement round, and regards the specified position as a water increase part and determines that it is a leak point The filtering means and a determining means is provided that, because according to the specifications of the pipeline followed by removal of noise components of the background, the leakage location of the fluid in the pipeline easily and reliably with a simple structure Can be found. In addition, since the traveling means travels in the pipeline and performs measurement, the work efficiency is improved.

Further, in the pipeline fluid leakage exploration method according to the present invention, the traveling means is disposed inside the pipeline where the fluid is circulated underground and the fluid flows, and the traveling means is discharged from the radioactive radiation source. Thermal neutron measurement means is provided for measuring thermal neutrons that have passed through the soil above and below the pipeline, and the thermal neutron measurement means is used to measure the thermal neutrons above and below the pipeline while running the traveling means at a predetermined speed. A pipeline fluid leakage exploration method for identifying a fluid leakage position of a pipeline after determining a thermal neutron measurement position on the pipeline and data of each thermal neutron corresponding to the position from a traveling distance , The thermal neutrons at the bottom of the pipeline are measured by the neutron moisture meter for lower moisture detection provided on the left and right sides of the traveling direction of the pipeline. After measuring the thermal neutrons at the top and bottom of the pipeline, obtain the increase / decrease pattern of the measured value measured by each lower moisture detection neutron moisture meter. Compared every measurement time, extract the measurement times of the same increase / decrease pattern, further extract the measurement times where the same pattern appears continuously for a predetermined number of times, and extract these consecutive measurements Since the position on the pipeline corresponding to the time is identified, and the identified position is regarded as a water increase portion and determined as a water leakage location, a fluid leakage location can be found efficiently.

  Thermal neutron measurement means for measuring the thermal neutrons emitted from radioactive sources and passed through the soil above and below the pipeline in the pipeline from which the fluid was discharged, for the purpose of quickly and accurately identifying the leak location of the pipeline The thermal neutron was measured while the thermal neutron measuring means was run by the running means, and the measurement data was made to correspond to the position data on the pipeline.

  The present invention will be described below with reference to embodiments shown in the drawings. FIG. 1 is an overall view of an exploration system according to an embodiment of the present invention. As shown in FIG. 1, the exploration system 2 according to the present embodiment is disposed on the ground with a exploration device 4 that is taken in and out of a pipeline 3 having a pipe diameter of 400 mm to 900 mm embedded in an agricultural water utilization facility. This exploration device 4 and a computer (central processing unit) 5 for exchanging control signals and data via radio are configured.

  As shown in FIGS. 2A and 2B, the exploration device 4 is installed in a traveling vehicle (traveling means) 10 in which front and rear chassis 11A, 11C are connected via a support base 11B, and the traveling vehicle 10. The neutron moisture meter (thermal neutron measuring means) 20 is provided. Each chassis 11A, 11C and support base 11C are connected by connecting pins 12A, 12B, respectively, and these three chassis 11A-11C bend in the traveling direction. Wheels 13A and 13B are provided on the front chassis 11A and the rear chassis 11C, respectively. A battery unit 14 is attached to the rear side of the front chassis 11A. Below the front chassis 11A, a drive motor 15 electrically connected to the battery unit 14 and drive wheels 16 connected to the drive motor 15 via a drive transmission member 18 are arranged.

  A high-sensitivity wireless camera 17 is provided on the front side of the front chassis 11A so as to transmit a video signal to the outside wirelessly. A neutron moisture meter 20 and an odometer 21 are provided on the support base 11B. The neutron moisture meter 20 measures the scattering of thermal neutrons in which fast neutrons emitted from a radiation source such as Cf-252 are decelerated by soil moisture (hydrogen), and sends the measured values to the outside. The source is 3.7 MBq or less exempted from the Radiation Hazard Prevention Law. The odometer 21 measures the travel distances D1, D2,..., Dn by rotation of the measurement disk that is rotated by traveling while the measurement disk is rotatably contacted with the inner surface of the pipeline, and sends the measured values to the outside. It is like that.

  As shown in FIG. 2B and FIG. 3, the neutron moisture meter 20 includes lower detection units (lower moisture detection neutron moisture meter) 20A, 20B and upper detection unit (upper moisture detection neutron moisture meter) 20C. It has. Each of the detection units 20A to 20C has a radiation source RS that emits fast neutrons and two neutron counters 32A and 32B that detect thermal neutrons in a long cylindrical housing 31. An absorbing material (heavy metal plate) 33 that supplements noise component neutrons is attached to the inside of the casing 32 in order to suppress interference from other radiation sources RS and reduce neutron rays of noise components. The support base 11B is provided with a gantry 34 composed of a pair of plates. A plurality of attachment holes 37 are formed in the upper portion of the gantry 34 depending on the pipe diameter type. The support arm 35 is attached to the attachment holes 37. The upper detection unit 20 </ b> C and the odometer 21 are connected to the support arm 35 via a pin 36. The upper detection unit 20C and the odometer 21 are arranged along the center line L1 of the support base 11B. The support arm 35 can be attached by appropriately selecting the upper and lower attachment holes 37 according to the pipe diameter type. Depending on the mounting position of the support arm 35, the upper detection portion 20C is opposed to the highest portion 3A on the upper surface of the pipeline 3 with a predetermined narrow gap SP1 therebetween, and the measurement disk of the odometer 21 is applied to the upper surface 3A of the pipeline. It comes to contact. The attachment hole 37 corresponds to, for example, a type having a pipe diameter of 400 mm or 600 mm.

  The upper detection unit 20 </ b> C measures background thermal neutrons that have passed through the soil above the pipeline 3. The pair of lower detection units 20A and 20B are provided on both the left and right sides of the lower part of the support base 11B with a lower inner surface of the pipeline 3 and a predetermined narrow gap SP2, respectively, and measure thermal neutrons that have passed through the soil below the pipeline. It is supposed to be. The pair of lower detection units 20A and 20B is provided by being shifted to both the right and left sides from directly below the center line L1 of the support base 11B when sand mud containing moisture is accumulated on the bottom of the pipeline 3 This is to eliminate the influence of. In addition, since water flows through the closed space in the pipeline, the sediment does not accumulate so as to hinder travel like an open channel.

  As shown in FIGS. 2A and 2B, the rear chassis 11C is electrically connected to the drive motor 15 and the high-sensitivity wireless camera 17 and controls them based on a command signal from the outside. A control unit 22 and a wireless communication unit 23 that transmits measurement values from the neutron moisture meter 20 and the odometer 21 to the outside and transmits an external command signal to the control unit 22 are provided. As shown in FIG. 1, the exploration device 4 drains the pipeline 3, and then enters and exits the air valve 6 of the pipeline 3. The air valves 6 are usually arranged at intervals of 100 m to 300 m. A radio repeater (transfer means) 40 is suspended inside the air valve 6 so as to face the space of the pipeline 3. The wireless repeater 40 is electrically connected to the computer 5 via a ground interface 41. The computer 5 controls the traveling vehicle 10 and the high-sensitivity wireless camera 17 of the exploration device 4 through the monitor unit 42 by input means (not shown), and captures measurement data from the neutron moisture meter 20 and measurement data from the odometer 21. The data is stored and processed. The high-sensitivity wireless camera 17 may be provided with a dedicated monitor device 43 on the ground as shown in FIG.

  As shown in FIG. 5, the computer 5 determines an increase / decrease pattern detection unit (determining an increase / decrease pattern) based on the measurement values respectively measured by the lower detection units 20 </ b> A and 20 </ b> B and determining an increase / decrease pattern. (Increase / decrease pattern detection means) 51 and the same pattern extractor for comparing the increase / decrease patterns of both lower detection units 20A, 30B detected by the increase / decrease pattern detector 51 for each measurement time and extracting the measurement times of the same increase / decrease pattern ( The same pattern extracting means) 52 and the same number of times of measurement of the same pattern extracted by the same pattern extraction unit 52 are further extracted as the number of times of the same pattern continuously appearing a predetermined number of times (in this embodiment, for example, 4 times). Then, the position on the pipeline corresponding to the extracted consecutive measurement times is identified, and the identified position is regarded as an increased portion of the water leakage. And a filter processing unit (filter processing unit) 50 including a determination unit (determination unit) 53 that determines that the location is determined according to the specifications of the pipeline, that is, the pipe diameter, the pipe thickness, and the pipe material (structure). The background noise component is removed. Then, as shown in FIG. 6, the filter processing unit 50 measures the number of measurement times in which the same pattern extracted by the same pattern extraction unit 52 continuously appears a predetermined number of times (in the table of FIG. For the ninth), the measured values of the lower detection units 20A and 20B are totaled for each measurement time, and statistical processing is performed.

  That is, the measured values of the lower detection units 20A and 20B that are simultaneously measured are combined values of randomly occurring radioactivity fluctuations and moisture change fluctuations. It is considered that the variation in the radioactivity that occurs randomly also causes the increase / decrease pattern of each of the lower detection units 20A and 20B to be random. The increase / decrease pattern here means whether it is increasing or decreasing with respect to the immediately preceding measurement value. Therefore, as shown in FIG. 5, for each of the lower detection units 20 </ b> A and 20 </ b> B, regardless of the background measurement value, as shown in FIG. 6th to 9th) is regarded as a variation portion of moisture change. Then, since the portion regarded as the fluctuation portion should represent the true moisture value, the measurement values of the lower detection units 20A and 20B are the same for the measurement times where the increase / decrease pattern is the same for a certain number of times. Is also considered to represent the true moisture value. Thus, in the filtering process, finally, the measured values of the respective lower detection units 20A and 20B are added, and as shown in FIG. 6, the peak of the water component is displayed through the statistical process, and the location of the water leakage is specified. I am doing so. As shown in FIG. 10, the pipeline 3 is installed on the base floor below the excavated groove 70, and around it, sand or high-quality earth and sand are used as a compactor (rammer) and a rammer. Filled with compaction.

  Next, a search method by the search system of the present invention will be described based on the operation of the search system according to the above embodiment. First, a section of the pipeline 3 where there is likely to be a water leakage point is specified in advance from a section of the pipeline to which the flow meter is attached. When the pipeline 3 to be searched is specified, the inflow of water into the pipeline 3 is stopped, and the water in the pipeline 3 is discharged. Next, the computer 5, the interface 41, and, if necessary, the monitor device 43 are installed on the ground near the air valve 6 of the pipeline 3 to be searched, and the air valve 6 is opened. The exploration device 4 is placed in the pipeline 3 from the opened air valve 6, and then the wireless repeater 40 is suspended from the opening of the air valve 6 and placed in the pipeline 3. In the exploration device 4, the support arm 35 is attached in advance to a predetermined attachment hole 37 of the gantry 34 according to the pipe diameter of the pipeline 3, and when the exploration device 4 is arranged in the pipeline 3, The detection unit 20C is opposed to the highest portion 3A on the upper surface of the pipeline 3 with a predetermined gap SP1 therebetween, and the odometer 21 is configured such that the measurement disk comes into contact with the upper surface 3A of the pipeline. When the exploration device 4 is arranged in the pipeline 3, a travel start position P0 is determined (see step S1 in FIG. 7), and data of the travel start position P0 is input to the computer 5 (step S2 in FIG. 7). reference).

  Next, the measurement work is started. In the measurement work, the traveling vehicle 10 is driven at a predetermined traveling speed (for example, 2.5 m / min, 10.0 m / min) V1 based on a command from the computer 5 (step of FIG. 7). S3), thermal neutrons are measured for each of the detectors 20A to 20C of the neutron moisture meter 20, and the measured count is output to the computer 5 as thermal neutron measurement data, and the mileage output from the odometer 21 D1, D2,..., Dn are also sequentially output to the computer 5 (see step S4 in FIG. 7). The computer 5 includes measurement data of background thermal neutrons that have passed through the soil above the pipeline 3 from the upper detection unit 20C, and measurement data of thermal neutrons that have passed through the soil below the pipeline from the lower detection units 20A and 20B. Are input and stored. The computer 5 inputs the input thermal neutron measurement data above the pipeline, thermal neutron measurement data below the pipeline, the travel distance Dn from the travel start point P0, and the travel speed V1 of the traveling vehicle 10. Data processing was performed (see step S5 in FIG. 7), and as shown in FIGS. 4B and 4C, the measurement position (m) and count (cps) of the pipeline 3 were taken on the x-axis and y-axis, respectively. Perform statistical processing on the graph. From this statistical processing result, a position that fluctuates more than the background moisture is determined as a water leak location (see step S6 in FIG. 7).

  4A shows an experimental pipeline in which pipelines having different specifications (tube diameter, tube thickness, and tube material (structure)) are connected, and the graphs shown in FIGS. 4B and 4C. The x-axis measurement positions correspond to the pipeline positions in FIG. The experimental pipeline in FIG. 4A is a centrifugal reinforced concrete pipe C1 having a pipe diameter of φ600 mm and a pipe thickness of 50 mm from the left end to 5 m (measurement position 0-5 m). 8m (measurement position 5-13m) core type prestressed concrete pipe C2 (pipe diameter φ600mm, pipe thickness 69mm (core type prestressed concrete part thickness 44mm, mortar coat thickness 25mm) ) Is connected. The core type prestressed concrete pipe C2 has a structure in which a core type prestressed concrete pipe is mortar coated. For each pipe C1, C2, calibration boxes (see FIG. 4D) B1, B2 containing wet loam (clay) containing water from the direction perpendicular to the pipe axis are inserted below the pipeline. The results of the experiment are shown in the graphs of FIGS. 4B and 4C. The calibration boxes B1 and B2 are both 500 mm in length in the tube axis direction, and can be refilled with materials having various moisture contents. 4B, the traveling vehicle 10 travels at a traveling speed V1 of 2.5 m / min. The graph of FIG. 4C illustrates the traveling vehicle 10 at a traveling speed V2 of 10 m / minute. Each case is shown.

  Among these graphs subjected to statistical processing, from FIGS. 4A to 4C, the centrifugal reinforced concrete pipe C1 having a pipe diameter of 600 mm and a pipe thickness of 50 mm is measured from 2 m to 2 at both the traveling speeds V1 and V2. Measured values from the lower detectors 20A and 20B within 5 m (thin solid lines are measured values of the lower detector 20A, broken lines are measured values of the lower detector 20B), and measured values of the upper detector 20C serving as the background It can be seen that it is significantly higher than (thick solid line). This raised portion coincides with the position of the calibration box B1 in the centrifugal reinforced concrete pipe C1. For this reason, with respect to the centrifugal reinforced concrete pipe C1, the position where the neutron moisture meter 20 fluctuates more than the background moisture is determined as the water leakage location.

  By the way, about core type prestressed concrete pipe C2, in addition to the pipe thickness being as thick as 69 mm, water from surrounding sand gathers in the mortar coat part, and a mortar layer having a relatively high moisture content is formed. As a result, the background becomes high, and the moisture increase at the water leakage point is hidden in the background. That is, the measurement values (thin solid lines and broken lines) of the lower detection units 20A and 20B are difficult to discriminate from the measurement values (thick solid lines) of the upper detection unit 20C serving as the background. For this reason, in the present embodiment, such a phenomenon that cannot be grasped only by the measurement of thermal neutrons is considered to be a change with respect to the background by performing a filtering process, and the assumed change part is determined with respect to the background. By highlighting the difference in fluctuation, the leak point is pinpointed accurately. That is, the measured values of the lower detection units 20A and 20B measured at the same time are combined values of the fluctuation of the radioactivity that occurs at random and the fluctuation of the moisture change, and the fluctuation of the radioactivity that occurs at random is detected by each lower detection. Since the increase / decrease pattern of the parts 20A and 20B is also considered to be random, as shown in FIG. It is considered to be a part. Since the portion regarded as the fluctuation portion should represent the true moisture value, the measurement values of the lower detection portions 20A and 20B are both true for the measurement times where the increase / decrease pattern is the same for a certain number of times. In the filter processing, the measurement values in the table of FIG. 5 are added to the sixth to ninth and FIG. 6 by adding the measured values of the lower detection units 20A and 20B. As shown from the distance of 8.5m to 9m in the table, the peak of water component is displayed through statistical processing to identify the location of water leakage.

  Filtering is performed as follows. First, when measurement values respectively measured by the lower detection units 20A and 20B are input to the computer 5, an increase / decrease pattern detection unit 51 determines increase / decrease compared with the immediately preceding measurement value to obtain an increase / decrease pattern ( (See (1) and (2) in FIG. 5 and step S11 in FIG. 8). Next, the same pattern extraction unit 52 compares the increase / decrease patterns of the lower detection units 20A and 30B detected by the increase / decrease pattern detection unit 51 for each measurement time, and extracts the measurement times of the same increase / decrease pattern (FIG. 5). (See (3) and step S12 in FIG. 8). Next, the measurement times (in the present embodiment, for example, four times) in which the same pattern continuously appears among the measurement times of the same pattern extracted by the same pattern extraction unit 52 by the determination unit 53 (see FIG. 5 (6th to 9th measurement times) are further extracted (see step S13 in FIG. 8), and these secondarily extracted measurement times (6th to 9th measurement times in FIG. 5) are extracted. For each of these measurement times, the measured values of the lower detection units 20A and 20B are summed (see (4) in FIG. 5 and step S14 in FIG. 8) on the pipeline corresponding to these extracted successive measurement times. Is identified and statistically processed (see (5) in FIG. 5), and the identified position (see distances 8.5m to 9m in FIG. 6) is regarded as an increased portion of water and determined as a water leak location (FIG. 8). Step S15).

  By performing the filtering process in this manner, even when the measurement values of the lower detection units 20A and 20B are hidden in the background of the upper detection unit 20C, it is possible to easily and reliably identify the water leakage location. Note that this filter processing is not applied only when hidden in the background, and it is needless to say that the processing may be executed even if it is not clear whether it is hidden in the background.

  In the exploration method according to the present invention, thermal neutrons that have passed through the soil above and below the pipeline 3 are continuously repeated by the neutron moisture meter 20 while the traveling vehicle 10 is traveling in the drained pipeline 3 at a predetermined speed V1. After the measurement, the thermal neutron measurement position on the pipeline 3 and each thermal neutron corresponding to the position from the measurement times 1, 2,..., N, the traveling speed V1 (V2) and the traveling distances D1, D2,. The measurement data is determined. After the measurement data is determined, the position where the moisture change increases is read from the combined value of the radioactivity fluctuation and the moisture change that occur randomly based on the calculated measurement data, and the leak position of the pipeline 3 is specified.

  Based on the exploration system 2 according to the above configuration, a full-scale model facility and the exploration device 4 were actually made, and experiments were performed using the personal computer 5. The experiment and the results will be described. FIG. 9 is an explanatory view showing a full-scale model facility. FIG. 4D shows a vertical section of the model facility. As shown in FIG. 9, the model facility dug a part of the ground to a depth of 2.3 m to form a square pyramid-shaped excavation groove 60 in which a slope 61 was formed from the upper opening toward the bottom. G is the ground surface, and experimental pipelines C1 and C2 (see FIG. 4A) are arranged on one side 61A of the slope 61 at a predetermined interval. The experimental pipelines C1 and C2 were laid on a sand layer having a base floor thickness of 0.5 m. Below the experimental pipelines C1 and C2, calibration box grooves 63 and 64 for inserting and removing the calibration boxes B1 and B2 (see FIG. 4A) are formed in the bottom portion 62 where the foundation concrete is cast. The The calibration box grooves 63 and 64 are provided in a direction perpendicular to the tube axes of the experimental pipelines C1 and C2.

  As shown in FIG. 4A, the experimental pipelines C1 and C2 are centrifugal reinforced concrete pipes C1 having a diameter of 600 mm and a pipe thickness of 50 mm from the left end to 5 m. An 8 m core type prestressed concrete pipe C2 (pipe diameter φ600 mm, pipe thickness 69 mm) is connected to the right end. The calibration boxes B1 and B2 are both 500 mm in length in the tube axis direction, and can be refilled with materials having various moisture contents. The calibration box grooves 63 and 64 are respectively provided in the calibration box B1 between 2.0 m-2.5 m from the left end C1L of the centrifugal reinforced concrete pipe C1, and in the calibration box B2 of the core type prestressed concrete pipe C2. It can be disposed between the left end C2L and 3.5 m to 4.0 m (from the left end C1L of the centrifugal reinforced concrete pipe C1 to 8.5 m to 9.0 m). On one side 61A of the slope 61, one side 66 of the experimental pipelines C1 and C2 and both open end portions C1L and C2R are exposed to the outside, and a steel shaft 65 is assembled. 67 is assembled. In the space SP3 in which the shaft assembly 65 and the acrylic plate 67 are assembled, sand 68 having a natural moisture content is introduced. An observation window 69 is formed on one side 66 of the experimental pipelines C1 and C2.

  In the experimental pipelines C1 and C2, the exploration device 4 is inserted from one of the open ends C1L and C2R, and the travel start position P0 is determined. In the experiment, calibration boxes B1 and B2 each filled with wet loam containing a large amount of water component were arranged below the experimental pipelines C1 and C2 through both calibration box grooves 63 and 64 ((D in FIG. 4). )reference). As the exploration device 4, an experimental device having the same configuration as the device shown in FIGS. The total length of the experimental apparatus 4 is 1575 mm, the width is 310 mm, and the front and rear direction dimensions of the front chassis 11A, the support platform 11B, and the rear chassis 11C are 521 mm, 458 mm, and 375 mm, respectively, and the front chassis 11A and the support platform 11B. The connecting portion dimensions and the connecting portion dimensions of the support base 11B and the rear chassis 11C are both 60 mm. The experimental apparatus 4 corresponds to the pipe diameters 600 mm of the experimental pipelines C1 and C2, and attaches the support arm 35 to the upper mounting hole 37 of the gantry 34.

  The experiment was conducted by running the exploration device 4 in the experimental pipelines C1 and C2. After the traveling of the exploration device 4, the thermal detectors passing through the upper and lower soils of the experimental pipelines C1 and C2 are continuously and repeatedly measured by the upper detector 20C and the lower detectors 20A and 20B of the neutron moisture meter 20, , N, travel speed V1 (V2) and travel distances D1, D2,..., Dn, the thermal neutron measurement position on the experimental pipelines C1, C2 (the left end of the experimental pipeline C1) The part C1L is defined as a travel start position P0 (0m), a travel distance (m) from this position, and measurement data of each thermal neutron corresponding to the position (count, the count here is based on the natural water content of sand) The count deviation). FIG. 4B shows a case where the traveling speed is 2.5 m / min, and FIG. 4C shows a case where the traveling speed is 10 m / min. The vertical axis in the figure is shown as the deviation from the natural water content of the back sand.

  The results are shown in FIGS. 4A to 4C. 4B and 4C, the measured values measured by the lower detectors 20A and 20B for the experimental pipeline C1, that is, a centrifugal reinforced concrete pipe having a length of 5 m, a pipe diameter of 600 mm, and a pipe thickness of 50 mm. Compared to the background (thick solid line) measured by the upper detector 20C over the distance from the left end C1L of the experimental pipeline C1 from 2.0 m to 2.5 m. Show significant fluctuations. This position matches the position of the calibration box B1, and it can be seen that the presence of the water component below the experimental pipeline C1 is indicated.

  For the experimental pipeline C2, that is, a core type prestressed concrete pipe having a length of 8 m, a pipe diameter of φ600 mm, a pipe thickness of 69 mm (concrete pipe thickness of 44 mm, and a mortar coat of 25 mm) is shown in FIGS. As is clear from the above, the measurement values measured by the lower detection units 20A and 20B are hidden behind the background and cannot be discriminated. For this reason, as a result of performing a filter process (refer FIG. 5) about the measured value obtained about the experimental pipelines C1 and C2, the result as shown in FIG. 6 was obtained. As a result of removing background noise components as shown in FIG. 6, the distance from the starting point (C1L, P0) for the experimental pipeline C2, that is, the core type prestressed concrete pipe, is 8.5 m to 9. The position fluctuates greatly up to 0 m, and this position matches the position of the calibration box B2, which clearly indicates the presence of the water component below the experimental pipeline C2. In addition, the presence of the water component below the experimental pipeline C1 that matches the position of the calibration box B1 also appears remarkably by this filter processing. Both calibration boxes B1 and B2 can be refilled with materials with various water content ratios (sand, gravel, clay, etc.). By analyzing the above, it is possible to reliably identify the water leakage location without being influenced by the soil layer under the foundation (see FIG. 10).

  Thus, as shown in FIGS. 4B and 4C, when the measurement speed is 2.5 m / min, the count (background) of the portion other than the water leakage point is stable at ± 100. . Moreover, in the leak location of the centrifugal reinforced concrete pipe C1, the counts of the lower detection units 20A and 20B are simultaneously increased by 1000 or more, whereas the count of the upper detection unit 20C shows a value within the background fluctuation. However, at the water leakage position of the core type prestressed concrete pipe C2, the counts of the lower detection units 20A and 20B increased only to about 150, and the peak position shifted. At a measurement speed of 10 m / min, the background becomes ± 300 and the leakage of the centrifugal reinforced concrete pipe C1 can be detected as a peak, but the leakage of the core type prestressed concrete pipe C2 is hidden in the background. For this reason, filter processing is performed. Fig. 6 shows the calculation result obtained by converting the measured value per second to the average value for 6 seconds (0.25m) for the scanning speed of 2.5m / min. The water leakage portion of the seam of the core type prestressed concrete pipe C2 at a distance of 8.8 m is clearly detected.

  In the above embodiment, the water use pipeline is used for water leakage exploration. However, the present invention is not limited to this, and any other fluid (oil, liquid chemical product) can be used as long as it can be detected by a neutron moisture meter. Needless to say, the present invention can also be applied to an embedded pipeline through which water and sewage water, circulating water in a hot / cold water supply / discharge system, etc. circulate. In the above embodiment, the measurement value of the thermal neutron is made to correspond to the distance from the travel start point P0 based on the travel distance measured by the odometer 21, but it is not limited to this. The measurement value of the thermal neutron is made to correspond to the distance from the travel start point P0 based on the predetermined constant travel speed and travel time of the traveling vehicle 10, and the search for the leak point is monitored over time. Good. Furthermore, as shown in FIG. 10, the upper detection unit may be configured by two neutron moisture meters 20C1 and 20C2.

It is explanatory drawing which shows the whole fluid leak investigation system of the pipeline which concerns on one embodiment of this invention. Example 1 (A), (B) is the top view and side view which respectively show the search apparatus of the search system of FIG. It is a longitudinal cross-sectional view which shows arrangement | positioning in the pipeline in the longitudinal cross-section of the neutron moisture meter provided in the exploration apparatus of FIG. (A) is an explanatory diagram showing the positions of different pipelines (centrifugal reinforced concrete pipe C1 and core-type prestressed concrete pipe C2) and calibration boxes B1 and B2 in a model facility, (B) and (C) are The graph which shows the example of a measurement of the leak location of an experimental pipeline, respectively, (D) is sectional drawing which shows the longitudinal cross-section of a model facility. It is an explanatory view showing the method of filter processing, and a graph showing the result of statistical processing. It is a graph which shows the example of application of filter processing. It is a flowchart which shows the determination method when the measured value of a lower part detection part is not hidden in the background of an upper part detection part. It is a flowchart which shows the determination method using the filter process in case the measured value of a lower part detection part is hidden in the background of an upper part detection part. It is explanatory drawing which shows the full-scale model facility used for experiment. It is explanatory drawing which shows the measurement position of the soil layer structure of a general pipeline, and the up-and-down neutron moisture meter in a pipeline.

Explanation of symbols

2 Fluid leakage exploration system 3 Pipeline 4 Exploration device (traveling means)
20 Neutron moisture meter (thermal neutron measurement means)
20A, 20B Lower detection part 20C Upper detection part RS Radioactive radiation source

Claims (9)

In a fluid leakage exploration system for pipelines that are buried underground and in which fluid flows, traveling means are placed in the pipeline from which the fluid has been discharged, and the traveling means are discharged from radioactive sources and pass through the soil above and below the pipeline, respectively. A thermal neutron measuring means for measuring the measured thermal neutrons, controlling the travel of the traveling means to determine the thermal neutron measurement position on the pipeline and the measurement data of each thermal neutron corresponding to the position, and the fluid of the pipeline It has a central processing unit that identifies the leak location ,
The thermal neutron measurement means is provided in the upper center of the vehicle body so as to be displaceable in the vertical direction. A pair of neutron moisture meters for detecting lower moisture, each of which is provided at a predetermined interval from the inner surface of the line and measures thermal neutrons that have passed through the soil below the pipeline,
The central processing unit includes an increase / decrease pattern detection means for obtaining an increase / decrease pattern based on measurement values respectively measured by the lower moisture detection neutron moisture meters, and both lower moisture detection neutrons detected by the increase / decrease pattern detection means. The same pattern extraction means that compares the increase / decrease pattern of the moisture meter every measurement time and extracts the measurement times of the same increase / decrease pattern, and the same pattern is continuously selected from the measurement times of the same pattern extracted by the same pattern extraction means And a determination means for determining a position on the pipeline corresponding to the extracted consecutive measurement times, and determining the identified position as a water leakage portion by regarding the specified position as a moisture increase portion. filtering means having provided, and removing the noise component of the background according to the specifications of the pipeline Pipeline fluid leakage exploration system. In a fluid leakage exploration system for a pipeline that is buried underground and in which a fluid flows, a traveling unit that is disposed inside the pipeline from which the fluid is discharged and whose drive is controlled based on a command signal from the outside, and the traveling unit A thermal neutron measuring means that has a radioactive ray source, is emitted from this radiation source and passes through the soil above and below the pipeline, and outputs to the outside by measuring the thermal neutrons every predetermined time; and provided in the traveling means, Travel distance measuring means that measures the travel distance of the travel means and outputs it to the outside, and is placed on the ground, and the travel means is freely operated via the monitor by the input means to travel at a constant travel speed, and thermal neutron measurement The thermal neutron measurement value and the mileage measurement value output from the means and the mileage measurement means, respectively, and the traveling speed data of the traveling means are input, and these data are input. Is stored in the memory and processed, and the measurement position on the pipeline is calculated from the traveling speed and distance for each measurement of thermal neutrons, and the data of each thermal neutron above and below the pipeline at these measurement positions. And a central processing unit that identifies the fluid leakage position of the pipeline ,
The thermal neutron measurement means is provided at the center of the upper part of the vehicle body so as to be vertically displaceable, and an upper moisture detection neutron moisture meter for measuring background thermal neutrons that have passed through the soil above the pipeline, and pipes on the left and right sides of the lower part of the vehicle body. A pair of neutron moisture meters for detecting lower moisture, each of which is provided at a predetermined interval from the inner surface of the line and measures thermal neutrons that have passed through the soil below the pipeline,
The central processing unit includes an increase / decrease pattern detection means for obtaining an increase / decrease pattern based on measurement values respectively measured by the lower moisture detection neutron moisture meters, and both lower moisture detection neutrons detected by the increase / decrease pattern detection means. The same pattern extraction means that compares the increase / decrease pattern of the moisture meter every measurement time and extracts the measurement times of the same increase / decrease pattern, and the same pattern is continuously selected from the measurement times of the same pattern extracted by the same pattern extraction means And a determination means for determining a position on the pipeline corresponding to the extracted consecutive measurement times, and determining the identified position as a water leakage portion by regarding the specified position as a moisture increase portion. filtering means having provided, and removing the noise component of the background according to the specifications of the pipeline Pipeline fluid leakage exploration system.   3. The pipeline fluid leakage exploration system according to claim 2, wherein the traveling means includes a vehicle body in which a plurality of chassis are connected to each other so as to be bent, and travels along substantially the center line of the pipeline. The neutron moisture meter is configured with a radiation source that emits fast neutrons and a neutron counter that detects thermal neutrons in the housing, and the interference from other radiation sources is suppressed in the housing. The pipeline fluid leakage exploration system according to claim 2 or 3 , wherein an absorbing material for reducing neutron beams is provided. The filter processing means totalizes the measured values of the neutron moisture meters for detecting both lower moisture for each measurement time for which the same pattern extracted by the same pattern extraction means continuously appears a predetermined number of times, and performs statistical processing. The pipeline fluid leakage exploration system according to claim 2 .   4. The pipeline fluid leakage exploration system according to claim 2 or 3, wherein the traveling means is provided with a photographing device for copying the state inside the pipeline and transmitting the image wirelessly to an external monitor. The traveling means outputs the video signal from the imaging device and the data from the thermal neutron measuring means and the traveling distance measuring means to the outside wirelessly, and also transmits the command signal from the outside to the control unit of the traveling means. The pipeline fluid leakage exploration system according to claim 6 , wherein a communication unit is provided, and the wireless communication unit communicates with the outside through transfer means arranged inside the pipeline. Heat is measured by measuring the thermal neutrons that are buried in the underground and where the fluid flows, inside the pipeline where the fluid is discharged, and are emitted from the radioactive source and passed through the soil above and below the pipeline. A neutron measurement means is provided, and thermal neutrons above and below the pipeline are measured by the thermal neutron measurement means while the traveling means is traveling at a predetermined speed, and the thermal neutron measurement position on the pipeline and its position are determined from the traveling speed and traveling distance. After determining the data of each corresponding thermal neutron, it is a pipeline fluid leakage exploration method for specifying the fluid leakage position of the pipeline,
Measure the thermal neutrons on the lower side of the pipeline with the lower moisture detection neutron moisture meters respectively provided on the left and right sides of the traveling direction of the traveling means, and after measuring the thermal neutrons above and below the pipeline according to the specifications of the pipeline, Find the increase / decrease pattern of the measured values measured by each lower moisture detection neutron moisture meter, extract the same increase / decrease pattern measurement times by comparing the increase / decrease pattern for both lower moisture detection neutron moisture meters for each measurement time, Of the extracted measurement times of the same pattern, the measurement times in which the same pattern appears continuously a predetermined number of times are further extracted, and the positions on the pipeline corresponding to the extracted consecutive measurement times are specified and specified. A method for searching for a fluid leak in a pipeline, characterized in that the position is regarded as a water increase part and is determined as a water leak location . Extracted the same pattern is continuously for a predetermined number of times appears measurement times, after the sum of the measured values of the two lower moisture detecting neutron moisture meter per their measurement times, to claim 8, characterized in that the statistical processing The method for exploring fluid leaks in pipelines as described.

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