JPH07217773A - Method of detecting underground buried article - Google Patents

Abstract

PURPOSE:To detect an article buried underground, which is irrespective of a magnetic or nonmagnetic one, without digging up. CONSTITUTION:A sheet 10 to be detected incorporating a band-like flexible magnet which is unidirectionally magnetized, is buried in the vicinity of an underground buried article 14, and is detected by a magnetic detector 32 on the ground. Accordingly, the underground buried article can be detected conveniently at a low cost on the ground without digging up its. Further, this method does not limit the material of the underground buried article to a specific one, and accordingly, is variously usable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting underground buried objects such as water pipes and gas pipes buried in the ground from the ground.

[0002]

2. Description of the Related Art Conventionally, various buried objects such as gas pipes, water and sewer pipes, power lines, and communication lines buried underground are repaired,
Alternatively, when burying a new buried object near the existing buried object, it is necessary to dig up the ground again. In such excavation work, the buried object may be damaged or damaged by an excavator such as a power shovel. Therefore, in order to inform the existence of the buried object in the ground above the buried object, a buried object sign indicating a warning or the like is buried together with the buried object, and the operator is alerted to damage or damage the buried object. Was prevented. Examples of such buried object markers include those described in JP-A-61-59084. However, this method was inconvenient because it was possible to confirm the existence of the buried object only after the ground was dug up because the buried object sign was simply buried in the ground. Therefore, various detecting means have been devised to obtain information on the buried object from the ground without digging up the ground.

[0003]

For example, a conductor such as a conductive foil or a conductive wire is used as an underground buried object mark as shown in FIG.
As shown in Fig. 1, a non-conductive or non-magnetic buried object 1
4 is embedded together with the conductor 4 and the conductor 2 is used for detection.
2 has a means for transmitting a signal from a transmitter 24 and detecting it from the ground by an electromagnetic detector 26 using electromagnetic induction. However, with this means, if a part of the conductor 22 is broken by re-excavation or the like, it can be detected only between the transmitter 24 and the cut portion. Also,
There is also a method in which an element that resonates at a specific frequency is buried in the vicinity of the underground buried object together with the underground buried object, and the element is detected from the ground by a detector using electromagnetic induction. With this method, there is no risk of functional deterioration due to accidents such as breakage of conductive wires, but if the depth of the buried object is deep, detection is difficult and it is very expensive and inconvenient. When the underground buried object is a magnetic material such as a steel pipe or cast iron pipe, as shown in FIG.
By using, it is possible to detect a change in the geomagnetism and detect the presence of the underground buried object 28, but this means has a shallow detection depth and cannot be detected when the buried object is deeply embedded. It cannot be applied to buried underground of non-magnetic material such as polyethylene pipe.

The present invention has been made to solve the above-mentioned problems, and it does not matter whether the buried object buried in the ground is magnetic or non-magnetic, and without excavating the ground,
The present invention also provides a method for detecting an underground buried object that can detect even a partial breakage.

[0005]

According to the method of detecting an underground buried object of the present invention, a sheet to be detected having a strip-shaped flexible magnet magnetized in a single direction is buried near the underground buried object. Aside
It is characterized in that the sheet to be detected is detected from the ground by a magnetic detector.

At this time, it is preferable that the flexible magnet is magnetized along the thickness direction of the sheet to be detected. Moreover,
It is more preferable to embed the sheet to be detected so that the S pole is located above. Furthermore, it is preferable that a flexible magnet is attached to the support.

[0007]

According to the present invention, since the magnetic force of the sheet to be detected buried in the ground together with the underground buried object is detected from the ground by the magnetic detector, a simple structure causes a significant cost increase. It is possible to detect underground buried objects without digging up the ground. Further, it is possible to detect whether or not the underground buried object is a non-magnetic material, regardless of its material. In addition, it is not necessary to connect the detected sheet to a transmitter, etc., so that not only defects such as breakage do not occur, but it is also possible to bury it intentionally in a separated state, and it is easy to carry and work when burying It is also possible to increase the ease of

Further, since the flexible magnet is magnetized along its thickness direction, it is not affected by the reversal of the magnetic force,
The detection by the magnetic detector can be made easier.
Furthermore, when using in the Northern Hemisphere like in Japan, S
By embedding the detection target sheet so that the poles are located above, the influence of geomagnetism can be reduced. Furthermore, by mounting the flexible magnet on the support to form the detection target sheet, it is possible to protect the flexible magnet and facilitate the burying work.

[0009]

EXAMPLE An example of the present invention will be described below. The method for detecting an underground buried object of the present embodiment is particularly suitable for detecting a pipe such as a water pipe, and as shown in FIG. 1, the detection target sheet 10 is placed in the vicinity of the underground buried object 14 in advance. Underground object 1
It is buried in the ground together with 4. Here, the detected sheet 10 is composed of a strip-shaped flexible magnet magnetized in a single direction. A so-called plastic magnet, ferrite rubber, or the like can be applied to the flexible magnet. Since it has flexibility like a plastic magnet or ferrite rubber, it can be easily carried into the work site, transported and buried. In addition, if it has flexibility, it has high durability against the occurrence of ground subsidence and vibration. Further, the flexible magnet needs to be magnetized in a single direction. The magnetization direction is
The strip-shaped flexible magnet may be in the width direction, the length direction, or the thickness direction, but is preferably in the thickness direction. Since the magnetic polarity weakens in the middle part between the two poles of the magnet, it is easily affected by the reversal of the magnetic force in the width direction and the length direction, making it difficult to detect. This is because no serious trouble occurs.

When the magnetizing direction is the thickness direction, it is preferable to bury the magnet in the ground so that the S pole is located above. This is because, due to the influence of the vertical distribution of the earth's magnetism, in a place located in the northern hemisphere like Japan, when the N pole is located above, there is a place where the magnetic force direction is reversed, which makes the detection work complicated. When used in the Southern Hemisphere, it is preferable to bury the N pole upward.

The sheet to be detected is, as shown in FIG.
It is preferable that the flexible magnet 16 is mounted on the support 18 to be configured. The support 18 is in the form of a long film, and the flexible magnet 16 is attached by adhesion or the like. The material of the support 18 is not particularly limited, but polyolefins, particularly polyethylene and polypropylene, polyethylene terephthalate, polyamide, ethylene-vinyl alcohol copolymer resin (EVOH: saponified ethylene-vinyl acetate copolymer), Vinylidene chloride resin (PVDC)
Can be applied. Further, instead of using such a synthetic resin alone, a plurality of types can be used.

The support 18 preferably has overlapping portions 12, 12, ... As shown in FIG. Each overlapping portion 12 is fixed by spot welding. Welding part 20 by this spot welding
Can permeate moisture in the ground and prevent weakening of the ground. The overlapping portion 12 may be fixed by sewing using a sewing machine or the like. The fixing by sewing has a higher production speed than that by welding, and the cost can be reduced. When the flexible magnet 16 is attached to the support 18 to form a sheet to be detected, twisting of the flexible magnet 16 can be prevented during burying, and the burying work becomes easy. Further, in the marginal portion of the support 18, for example, the name of the management company of the buried object, the purpose of the buried object (water supply, sewer, gas pipe, communication cable, power cable, etc.), material (steel pipe, cast iron pipe, polyethylene pipe, fume) It is also possible to display information such as pipes), size, burial depth, burial time, control number, and construction company name. Further, the flexible magnet may be attached to the support so that the support surrounds the flexible magnet. By doing so, the flexible magnet can be protected.

The underground buried object can be detected easily by detecting the sheet to be detected as described above with a magnetic detector. As the magnetic detector, a commercially available magnetic detector that is generally commonly used can be used. If it is expected that detection will be difficult due to the depth of the underground buried object or the sheet to be detected, etc., increase the thickness or width of the flexible magnet, or use the flexible magnet. This can be dealt with by using magnetic anisotropy. For example, according to the research by the present inventor, the thickness is 0.5 mm,
The detection depth limit of the detection sheet with a width of 50 mm and a length of 2 m (the plastic magnet used is isotropic) is 2.0.
Although it was m, the detection depth limit was 2.5 m with only the width changed to 100 mm, and the detection depth limit could be increased.

In the method of detecting an underground buried object according to this embodiment, since the magnetic force is detected, the underground buried object can be detected from the ground without digging up the ground.
In addition, regardless of the material of the underground buried object (for example, even a non-magnetic buried object such as a polyethylene pipe), any underground buried object can be detected. Further, it is not necessary to connect the detected sheet to a transmitter or the like, and there is no problem of function stop due to disconnection or the like. Further, it is also possible to divide the sheet to be detected into strips and embed a large number of sheets to be detected at arbitrary intervals, which makes it possible to further facilitate the embedding work. Further, since the flexible magnet is a permanent magnet, it does not require a battery or the like, requires less maintenance, and can be buried in the ground for a long time with a sense of security.

The detection method of the present invention can be used in combination with other detection methods. For example, two types of multifaceted detection means can be implemented by mounting a conductive wire connected to a transmitter together with a flexible magnet on the support of the present invention to form a detected sheet.

[0016]

According to the method of detecting an underground buried object according to the first aspect of the present invention, a sheet to be detected having a strip-shaped flexible magnet magnetized in a single direction is buried near the underground buried object. The detection sheet is detected from the ground by a magnetic detector.

A method for detecting an underground buried object according to claim 2 is:
The flexible magnet is magnetized along the thickness direction of the sheet to be detected. The method for detecting an underground buried object according to a third aspect is characterized in that the detection target sheet is buried so that the S pole is located above. A method of detecting an underground buried object according to a fourth aspect is characterized in that a flexible magnet is mounted on a support.

According to the present invention, it is possible to detect an underground buried object from the ground without digging up the ground while being simple and low in cost. Further, since it can be applied without being limited to the material of the underground buried object, it is used for detecting various underground buried objects such as steel pipes and polyethylene pipes, and has high versatility. Further, since the sheet to be detected is not connected to a transmitter or the like, a defect such as breakage does not occur. In addition, since it is possible to intentionally divide and bury it, it is possible to enhance the ease of transportation and workability when burying. Further, since the flexible magnet is magnetized along the thickness direction, it is possible to make the detection by the magnetic detector easier. Further, by embedding the detected sheet so that the S pole is located above, it is possible to reduce the influence of geomagnetism when used in the northern hemisphere as in Japan. Furthermore, by mounting the flexible magnet on the support to form the detection target sheet,
The burying work can be facilitated together with the protection of the flexible magnet.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining a detection method according to an embodiment of the present invention.

FIG. 2 is a perspective view of a detection target sheet according to an embodiment of the present invention.

FIG. 3 is a schematic diagram for explaining a conventional detection method.

FIG. 4 is a schematic diagram for explaining a detection method of a conventional example.

[Explanation of symbols]

 10 Detected Sheet 14 Underground Object 16 Flexible Magnet 18 Support 28 Underground Object 32 Magnetic Detector

Claims (4)

[Claims] 1. A detection target sheet comprising a strip-shaped flexible magnet magnetized in a single direction is embedded near an underground buried object, and the detection target sheet is detected from the ground by a magnetic detector. A method for detecting an underground buried object, which is characterized by the above. 2. The method for detecting an underground buried object according to claim 1, wherein the flexible magnet is magnetized along the thickness direction of the sheet to be detected. 3. The method for detecting an underground buried object according to claim 2, wherein the sheet to be detected is embedded so that the S pole is located above it. 4. The method for detecting an underground buried object according to claim 1, wherein a flexible magnet is attached to the support.