JPH0221289A - Detection of buried pipe - Google Patents
Detection of buried pipeInfo
- Publication number
- JPH0221289A JPH0221289A JP63171200A JP17120088A JPH0221289A JP H0221289 A JPH0221289 A JP H0221289A JP 63171200 A JP63171200 A JP 63171200A JP 17120088 A JP17120088 A JP 17120088A JP H0221289 A JPH0221289 A JP H0221289A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic field
- buried pipe
- distribution
- alternating current
- frequencies
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000001514 detection method Methods 0.000 title claims description 16
- 238000009826 distribution Methods 0.000 claims abstract description 66
- 238000000034 method Methods 0.000 claims description 39
- 239000006185 dispersion Substances 0.000 claims description 3
- 238000005259 measurement Methods 0.000 abstract description 10
- 238000010586 diagram Methods 0.000 description 5
- 238000009933 burial Methods 0.000 description 3
- 238000009412 basement excavation Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 230000005674 electromagnetic induction Effects 0.000 description 1
- 238000007619 statistical method Methods 0.000 description 1
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- Geophysics And Detection Of Objects (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明はガス管、水道管、電カケープルまたは電話ケー
ブル等の、地中に埋設された電気伝導性を有する埋設管
を磁気的に検知するための方法に関するものである。[Detailed Description of the Invention] (Industrial Application Field) The present invention magnetically detects electrically conductive underground pipes such as gas pipes, water pipes, electric cables, or telephone cables. It concerns a method for
（従来の技術）
地中に埋設された電気伝導性を有する埋設管や埋設ケー
ブル等（以後、埋設管として総称する）の位置、即ちそ
の直上位置と埋設深さを検知するための従来の方法とし
ては、通常は、手軽で比較的検知精度が良く、しかもい
ろいろな場所に適用が可能であることから磁気的検知方
法が多く使用されている。そしてかかる磁気的検知方法
では、埋設管に交流電流を流し、この交流電流が地表上
に作る磁場の分布から検知する方法が最も多く採用され
ており、この場合、埋設管に交流電流を流す方法として
は、直接に交流電流源を接続して流す直接法と、電磁誘
導を利用して埋設管に誘導電流を発生させる間接法とが
ある。(Prior art) A conventional method for detecting the position of electrically conductive buried pipes, cables, etc. buried underground (hereinafter collectively referred to as buried pipes), that is, the position immediately above them and the buried depth. Generally, magnetic detection methods are often used because they are simple, have relatively high detection accuracy, and can be applied to a variety of locations. The most commonly used magnetic detection method is to flow an alternating current through a buried pipe and detect from the distribution of the magnetic field created by this alternating current on the ground surface. There are two methods: a direct method in which an alternating current source is connected directly and an indirect method in which an induced current is generated in a buried pipe using electromagnetic induction.
かかる従来の方法を添付図面を参照して簡単に説明する
と、まず第５図に示す方法は、同様の磁気検知特性を有
する一対の磁気センサＳ１．Ｂ２を、その検知方向が平
行になるようにして、一定の距離ｄを隔てて一体に構成
した検知器りを用いる方法である。この方法は、検知器
りを地表面Ｅに沿って移動させながら磁気センサＳｔ、
Ｓ２によって水平方向の磁場成分を検知し、検知磁場が
極大になった位置を埋設管Ｐの直上位置であると判断し
、次いで磁気センサＳｌ、Ｓ２の出力Ｂｌ。Such a conventional method will be briefly explained with reference to the accompanying drawings. First, the method shown in FIG. 5 involves a pair of magnetic sensors S1. This is a method using a detector that is integrally configured with B2 separated by a certain distance d so that the detection directions thereof are parallel to each other. In this method, while moving the detector along the ground surface E, the magnetic sensor St,
The magnetic field component in the horizontal direction is detected by S2, and the position where the detected magnetic field becomes maximum is determined to be the position directly above the buried pipe P, and then the magnetic sensor Sl and the output Bl of S2 are detected.
Ｂ２から下式により埋設深さｒｌを算出するものである
。The burial depth rl is calculated from B2 using the following formula.
ｒｌ：＝ｄＸＢ２／ （Ｂｌ−８２）次に、第す図に
示す方法は、単一の磁気センサＳを設けた検知器Ｌ′を
用いる方法で、この方法は、前述の方法と同様に検知器
Ｌ′を地表面Ｅに沿って移動させながら磁気センサＳに
よって水平方向の磁場成分を検知し、検知磁場が極大に
なった位置を埋設管Ｐの直上位置であると判断した後。rl:=dXB2/ (Bl-82) Next, the method shown in FIG. While moving the container L' along the ground surface E, the horizontal magnetic field component is detected by the magnetic sensor S, and the position where the detected magnetic field becomes maximum is determined to be the position directly above the buried pipe P.
磁気センサＳの出力が前記極大検知出力の半分になるま
で検知器Ｌ′を更に移動し、その移動距離を埋設深さｒ
ｌとして検知するものである。直上位置から埋設深さｒ
ｌだけ水平方向に離れた点に於ける水平方向の磁場成分
Ｂ３が、直上位置に於ける極大検知磁場Ｂ１の半分にな
ることは次式により示される。The detector L' is further moved until the output of the magnetic sensor S becomes half of the maximum detection output, and the moving distance is expressed as the burial depth r.
It is detected as l. Burying depth r from directly above position
The following equation shows that the horizontal magnetic field component B3 at a point horizontally separated by l is half of the maximum detected magnetic field B1 at the position directly above.
Ｂ ３ ＝ ＣＸ １ ／ （”Ｘ ｒ ｌ Ｘ ｌ
／ （Ｍ＝ＣＸ１／２ｒｌ
＝８１／２
後者の方法は、単一の磁気センサを用いるので、前者の
方法のように一対の磁気センサの特性の違いによる誤差
を生じないという利点を有するものの、埋設深さを得る
ために、極大磁場を検知した後に再度センサを移動しな
ければならず、測定操作が煩雑であるという欠点を有し
ている。B 3 = CX 1 / ("X r l
/ (M=CX1/2rl =81/2 The latter method uses a single magnetic sensor, so unlike the former method, it has the advantage of not causing errors due to differences in the characteristics of the pair of magnetic sensors. In order to obtain the burial depth, the sensor must be moved again after detecting the maximum magnetic field, which has the disadvantage that the measurement operation is complicated.
（発明が解決しようとする問題点）
以上説明した方法等の、磁気的検知方法に於いて高精度
に埋設管を検知するためには、埋設管に流れる信号電流
の作る磁場のみを磁気センサが高精度に検知することが
必要である。しかしながら。(Problems to be Solved by the Invention) In order to detect buried pipes with high precision using magnetic detection methods such as the method described above, it is necessary for the magnetic sensor to detect only the magnetic field created by the signal current flowing through the buried pipes. It is necessary to detect with high precision. however.
現実に於いては、埋設管を流れる電流が作る磁場以外に
、多くの外来磁場、即ちノイズ磁場や、埋設管から漏洩
して地中に流れる電流、即ち地中電流が作る磁場が存在
し、これらが埋設管を流れる信号電流の作る磁場を歪め
、精度低下の原因になっている。これらのうち、前者の
外来のノイズ磁場は、信号電流が作る磁場との、周波数
の違いや位相の違いを利用して除去することが従来から
行われており、効果を上げているが、後者の地中電流が
作る磁場は、信号電流が作る磁場と周波数、位相ともに
同一であるため、これらによっては区別することができ
ず、除去が困難である。しかも、かかる地中電流の分布
は、地中の土壌の状態によって、または埋設管の電気的
特性によって大きく変化し、−律でないので測定した磁
場から、地中電流が作る磁場の影響を除く補正も困難で
ある。In reality, in addition to the magnetic field created by the current flowing through buried pipes, there are many external magnetic fields, such as noise magnetic fields, and magnetic fields created by currents that leak from buried pipes and flow into the ground, that is, underground currents. These distort the magnetic field created by the signal current flowing through the buried pipe, causing a drop in accuracy. Of these, the former type of external noise magnetic field has traditionally been removed by utilizing the difference in frequency and phase with the magnetic field created by the signal current, and this has been effective. The magnetic field created by the underground current has the same frequency and phase as the magnetic field created by the signal current, so it cannot be distinguished and is difficult to remove. Moreover, the distribution of such underground currents varies greatly depending on the condition of the underground soil or the electrical characteristics of the buried pipes, and is not constant, so the measured magnetic field is corrected to remove the influence of the magnetic field created by the underground currents. is also difficult.
こうして、地中電流が作る磁場の存在は、埋設管に直接
または間接的に交流電流を流し、それが地表上に作る磁
場により、該埋設管を検知する方法の原理上の誤差要因
となっており、また誤差の程度を操作者が知ることがで
きないという問題点がある。In this way, the existence of a magnetic field created by an underground current is a principle error factor in the method of detecting a buried pipe by passing an alternating current directly or indirectly through the underground pipe and using the magnetic field created by this on the ground surface. Furthermore, there is a problem in that the operator cannot know the extent of the error.
本発明は、以上の問題点を解決することを目的とするも
のである。The present invention aims to solve the above problems.
（問題点を解決するための手段）
本発明の構成を実施例に対応する第１図〜第６図を参照
して説明すると、まず特許請求の範囲第１項記載の方法
は、地中に埋設された電気伝導性を有する埋設管に直接
または間接的に交流電流を流し、それが地表上に作る磁
場により、該埋設管を検知する方法に於いて、該埋設管
には、異なった周波数の複数の交流電流を、同時または
時分割に流して、それらが地表上に作る複数の周波数の
交流磁場の分布を、同時または時分割に測定し。(Means for Solving the Problems) The structure of the present invention will be explained with reference to FIGS. In this method, an alternating current is passed directly or indirectly through a buried underground pipe having electrical conductivity, and the underground pipe is detected by a magnetic field created on the ground surface. Multiple alternating currents are passed simultaneously or in a time-division manner, and the distribution of alternating current magnetic fields of multiple frequencies that they create on the earth's surface is measured simultaneously or in a time-division manner.
それらの磁場分布を比較することにより、夫々の磁場分
布に基づいて算出した埋設管の位置の信頼性を判断する
ものである。By comparing these magnetic field distributions, the reliability of the position of the buried pipe calculated based on the respective magnetic field distributions is determined.
次に第２項記載の方法は、地中に埋設された電気伝導性
を有する埋設管に直接または間接的に交流電流を流し、
それが地表上に作る磁場により、該埋設管を検知する方
法に於いて、該埋設管には、異なった周波数の複数の交
流電流を、同時または時分割に流して、それらが地表上
に作る複数の周波数の交流磁場の分布を、同時または時
分割に測定し、それらの磁場分布を比較して、最も円筒
状磁場分布に近い磁場分布から埋設管の位置を算出する
ものである。Next, the method described in item 2 involves passing an alternating current directly or indirectly through a buried underground pipe having electrical conductivity.
In the method of detecting the buried pipe by the magnetic field it creates on the ground surface, multiple alternating currents of different frequencies are passed through the underground pipe simultaneously or in time division, and the magnetic field they create on the ground surface is The distribution of alternating current magnetic fields of multiple frequencies is measured simultaneously or time-divisionally, the magnetic field distributions are compared, and the position of the buried pipe is calculated from the magnetic field distribution closest to the cylindrical magnetic field distribution.
次に第３項記載の方法は、第１項または第２項記載の方
法に於いて、複数の周波数の交流磁場の分布の比較は、
磁場の最大値が一致するように正規化して行うものであ
る。Next, in the method described in item 3, in the method described in item 1 or 2, the comparison of the distribution of alternating magnetic fields of multiple frequencies is
This is done by normalizing so that the maximum values of the magnetic fields match.
次に第４項記載の方法は、第２項記載の方法に於いて、
測定した磁場分布の円筒状磁場分布からのずれは、地表
上の複数の位置で測定した磁場の方向を法線とする複数
の面が互いに交差する線のバラツキ具合により判断する
ものである。Next, in the method described in Section 4, in the method described in Section 2,
The deviation of the measured magnetic field distribution from the cylindrical magnetic field distribution is determined by the degree of dispersion in the lines where a plurality of planes whose normals are the direction of the magnetic field measured at a plurality of positions on the earth's surface intersect with each other.
次に第５項記載の方法は、第２項記載の方法に於いて、
測定した磁場分布の円筒状磁場分布からのずれは、水平
方向の各位置に於ける水平方向磁場成分と垂直方向磁場
成分の比が１位置に対して直線的に変化するかどうかを
測定して判断するものである。Next, in the method described in Section 5, in the method described in Section 2,
The deviation of the measured magnetic field distribution from the cylindrical magnetic field distribution is determined by measuring whether the ratio of the horizontal magnetic field component to the vertical magnetic field component at each horizontal position changes linearly with respect to one position. It is something to judge.
次に第６項記載の方法は、測定した磁場分布の円筒状磁
場分布からのずれは、水平方向の各位置に於ける水平方
向または垂直方向の磁場成分の絶対値が、ある位置に対
して線対称であるかどうかを測定して判断するものであ
る。Next, in the method described in Section 6, the deviation of the measured magnetic field distribution from the cylindrical magnetic field distribution is determined by the absolute value of the horizontal or vertical magnetic field component at each horizontal position relative to a certain position. This is to measure and determine whether or not there is line symmetry.
（作用及び実施例）
以上の本発明の作用を実施例に対応する図面に基づいて
説明すると次の通りである。(Operations and Examples) The operations of the present invention described above will be explained as follows based on the drawings corresponding to the examples.
まず第１図は、地中電流が作る磁場の影響を知るために
、該地中電流の分布及びその周波数特性を実際の配管系
に於いて測定した測定系を模式的に表わしたものである
。符号１は送信器で、これは深度Ｄ＝１．２ｍの埋設管
２の、地表３上の露出部４と、アース捧５間に接続して
該埋設管２に信号交流電流を供給する構成としている。First of all, Figure 1 schematically represents the measurement system used to measure the distribution of underground current and its frequency characteristics in an actual piping system in order to understand the influence of the magnetic field created by underground current. . Reference numeral 1 denotes a transmitter, which is connected between an exposed part 4 on the ground surface 3 of a buried pipe 2 at a depth of D = 1.2 m and a ground support 5 to supply a signal alternating current to the buried pipe 2. It is said that
該埋設管２を流れる信号交流電流の一部は、埋設管２か
ら漏洩して図中実線矢印で示す地中電流６となって地中
を流れ、やがてアース捧５に吸収される。A part of the signal alternating current flowing through the buried pipe 2 leaks from the buried pipe 2, becomes an underground current 6 shown by a solid line arrow in the figure, flows underground, and is eventually absorbed by the earthing shaft 5.
かかる地中電流６の分布は１例えば地電位分布により測
定することができる。即ち、地中の導電率が一様である
とするならば、地電位と地中電流の関係は定数倍になり
、それらの分布が一致するからである。かかる地電位分
布は、先端部のみで地中に接触するように構成した、一
対の地電位測定棒７，７′間の電位差を交流電圧計８で
測定して求め、該地電位測定棒７，７′の先端の深度Ｚ
を変化させることによって地電位の深度方向の分布を測
定することができる。The distribution of the underground current 6 can be measured, for example, by the earth potential distribution. That is, if the underground conductivity is uniform, the relationship between the earth potential and the underground current will be multiplied by a constant, and their distributions will match. This earth potential distribution is determined by measuring the potential difference between a pair of earth potential measuring rods 7 and 7' with an AC voltmeter 8, which are configured so that only their tips come into contact with the earth. , 7′ tip depth Z
By changing the , the depth distribution of the earth potential can be measured.
以上の構成に於いて、送信器１から１０２５Ｈｚ、１０
ｋＨｚ、５０ｋｌ（ｚ及びＬｏｏｋ）Ｉｚ（７）夫々ノ
周波数につき、８００ｍＡｒｍｓの信号電流を供給して
前述した測定を行った結果を第２図に示す。第２図に於
いて、縦軸は地電位測定棒７，７′の先端の深度Ｚ、そ
して横軸は埋設管２方向の地電位差を示すものである。In the above configuration, transmitter 1 transmits 1025Hz, 10
FIG. 2 shows the results of the measurements described above while supplying a signal current of 800 mArms at frequencies of kHz and 50 kl (z and Look) Iz (7), respectively. In FIG. 2, the vertical axis represents the depth Z at the tips of the earth potential measuring rods 7, 7', and the horizontal axis represents the earth potential difference in two directions of the buried pipe.
かかる結果から、次のことがわかる。From these results, the following can be understood.
まず、各周波数共に、埋設管２の深度に相当するＺ＝−
１，２ｍに於いて大きな地電位差となっており、これは
埋設管２から漏洩した電流の多くは、該埋設管２の近傍
を通ってアース捧５に向かって流れていることを示して
いる。かかる地中電流は埋設管２を中心にして対称な分
布であるので、埋設管２を流れる電流と同様に、該埋設
管２を中心軸とする円筒状磁場を作る。従って、かかる
地中電流は所定の円筒状磁場を歪ませず、埋設管２の検
知誤差の要因とはならない。First, for each frequency, Z = - which corresponds to the depth of the buried pipe 2.
There is a large ground potential difference between 1 and 2 meters, which indicates that most of the current leaking from the buried pipe 2 is flowing toward the ground beam 5 through the vicinity of the buried pipe 2. . Since this underground current has a symmetrical distribution around the buried pipe 2, it creates a cylindrical magnetic field with the buried pipe 2 as the central axis, similar to the current flowing through the buried pipe 2. Therefore, such underground current does not distort the predetermined cylindrical magnetic field and does not become a cause of detection error of the buried pipe 2.
以上に対して、地表付近の地電位分布は１周波数によっ
て大きな違いがあり、高周波になるほど地表付近の地電
位差が大きくなっており、これは高周波になるほど地中
電流は地表付近を多く流れることを示している。かかる
地表付近を流れる地中電流は、埋設管２を中心とした対
称分布を形成しないので、前記円筒状磁場を歪ませるも
のであり、また地表に近いことから歪ませる磁場も大き
くなり、検知誤差の大きな要因となる。そして、このよ
うに歪ませる磁場の大きさは周波数によって異なる。In contrast to the above, the earth potential distribution near the ground surface varies greatly depending on the frequency, and the higher the frequency, the larger the earth potential difference near the ground surface, which means that the higher the frequency, the more underground current flows near the ground surface. It shows. Such underground current flowing near the ground surface does not form a symmetrical distribution around the buried pipe 2, so it distorts the cylindrical magnetic field, and since it is close to the ground surface, the distorting magnetic field becomes large, resulting in detection error. This is a major factor. The magnitude of the magnetic field that distorts in this way varies depending on the frequency.
以上の特性は単なる一例であり、地中の土壌の状態や埋
設管２の電気特性または埋設管２の近傍の他の埋設物の
状態等によっては、磁場をより大きく歪ませる周波数も
異なってくるし、逆に周波数により磁場分布が変化しな
い場合もある。後者に於いては、測定した磁場分布は周
波数によって変化せず、このような場合には、地中電流
の影響による磁場の歪は小さい。The above characteristics are just examples; the frequency that distorts the magnetic field to a greater extent may vary depending on the condition of the underground soil, the electrical characteristics of the buried pipe 2, the condition of other buried objects near the buried pipe 2, etc. Conversely, there are cases where the magnetic field distribution does not change depending on the frequency. In the latter case, the measured magnetic field distribution does not change with frequency, and in such a case, the distortion of the magnetic field due to the influence of underground currents is small.
以上のことから、埋設管に異なった周波数の複数の交流
電流を、同時または時分割に流して、それらが地表上に
作る複数の周波数の交流磁場の分布を、同時または時分
割に測定し、それらの磁場分布を比較することにより、
夫々の磁場分布に基づいて算出した埋設管の位置の信頼
性を判断することができるのである。Based on the above, multiple alternating currents of different frequencies are passed through the underground pipes simultaneously or in a time-division manner, and the distribution of alternating current magnetic fields of multiple frequencies that they create on the ground surface is measured simultaneously or in a time-division manner. By comparing their magnetic field distributions,
It is possible to judge the reliability of the position of the buried pipe calculated based on each magnetic field distribution.
第３図は、前述した測定時に、磁気センサにより地表上
に於いて測定した交流磁場の分布を示すものであり、（
ａ）は水平方向、（ｂ）は垂直方向の磁場成分を示すも
のである。この測定例に於いては、磁場成分の分布は周
波数によって大きく異なり、前述したように地中電流の
影響が非常に太きいと判断でき、これらの周波数のいず
れかに対応する磁場分布により算出した埋設管２の位置
の信頼性も低いと判断することができる。Figure 3 shows the distribution of the alternating current magnetic field measured on the earth's surface by the magnetic sensor during the measurement described above.
(a) shows the magnetic field component in the horizontal direction, and (b) shows the magnetic field component in the vertical direction. In this measurement example, the distribution of the magnetic field component varies greatly depending on the frequency, and as mentioned above, it can be determined that the influence of the underground current is very large. It can also be determined that the reliability of the position of the buried pipe 2 is low.
しかしながら、これらの周波数のうち、例えば１０２５
１（ｚ、１ｏｋＨｚの磁場分布は、略円筒状磁場分布に
近く、最も近い１０２５Ｈｚの磁場分布により埋設管２
の位置を算出し、これを検知結果として採用することも
できる。However, among these frequencies, e.g.
The magnetic field distribution of 1(z, 1 kHz is close to a substantially cylindrical magnetic field distribution, and the closest magnetic field distribution of 1025 Hz causes the buried pipe 2
It is also possible to calculate the position of and use this as the detection result.
以上の方法に於いて、複数の周波数の交流磁場の分布の
比較は、磁場の最大値が一致するように正規化し、それ
以外の適所に於ける差等により比較するようにすれば、
周波数に対しての変化を定量化することができ、信頼性
判断に於ける合否判断の基準の設定も可能となるばかり
でなく、適宜の処理装置による自動処理も可能となる。In the above method, when comparing the distributions of alternating magnetic fields of multiple frequencies, normalize them so that the maximum values of the magnetic fields match, and compare based on the differences at other appropriate locations.
Changes with respect to frequency can be quantified, and it is not only possible to set criteria for pass/fail judgment in reliability judgment, but also automatic processing by an appropriate processing device is possible.
次に、 ？Ｉ＋＋定した磁場分布の円筒状磁場分布から
のずれは、以下に示すような各種の方法を適用して行う
ことができる。第４図はその一例を模式的に表わしたも
ので、この方法は、地表上の複数の位置で測定した磁場
の方向を法線とする複数の面が互いに交差する線のバラ
ツキ具合により判断するもので、かかるバラツキ具合は
適宜の統計学的手法により定量化することができる。即
ち、この方法では、バラツキ具合が小さい程、円筒状磁
場分布に近いと判断するもので、例えばバラツキの偏差
を数値で表現して定量的な指標にしたり、平均値を中心
とした、ある範囲に交線が全体の何％存在しているかを
もって指標とすることができる。next, ? The deviation of the I++ fixed magnetic field distribution from the cylindrical magnetic field distribution can be achieved by applying various methods as shown below. Figure 4 schematically shows an example of this. This method is determined based on the degree of dispersion in the lines where multiple planes intersect with each other with the direction of the magnetic field measured at multiple locations on the earth's surface as their normal. The degree of such variation can be quantified using an appropriate statistical method. In other words, in this method, the smaller the degree of variation, the closer it is to a cylindrical magnetic field distribution. The percentage of the total number of intersecting lines can be used as an index.
この他の方法としては、例えば昭和６２年特許願第２８
０７４０号の願書に添付した明細書及び図面に開示され
ているように、■・・・測定した磁場分布の水平方向の
各位置に於ける水平方向磁場成分と垂直方向磁場成分の
比が、位置に対して直線的に変化するかどうかを測定し
て判断する方法。Other methods include, for example, Patent Application No. 28 of 1988.
As disclosed in the specification and drawings attached to application No. 0740, ■...The ratio of the horizontal magnetic field component to the vertical magnetic field component at each horizontal position of the measured magnetic field distribution is A method to measure and determine whether there is a linear change in .
■・・・測定した磁場分布の水平方向の各位置に於けろ
水平方向または垂直方向の磁場成分の絶対値が、ある位
置に対して線対称であるかどうかを測定して判断する方
法等を適用し得ることは勿論である。■...A method of measuring and determining whether the absolute value of the horizontal or vertical magnetic field component at each horizontal position of the measured magnetic field distribution is line symmetrical with respect to a certain position. Of course, it can be applied.
（発明の効果）
本発明は以上の通り、地中に埋設された電気伝導性を有
する埋設管に直接または間接的に交流電流を流し、それ
が地表上に作る磁場により、該埋設管を検知する方法に
於いて、該埋設管には、異なった周波数の複数の交流電
流を、同時または時分割に流して、それらが地表上に作
る複数の周波数の交流磁場の分布を、同時または時分割
に測定し、それらの磁場分布を比較するので、地中電流
による影響の程度を知り、夫々の磁場分布に基づいて算
出した埋設管の位置の信頼性を判断することができると
共に、それらの周波数の磁場分布に於いて、最も円筒状
磁場分布に近いものから埋設管の位置を算出することに
より、結果として埋設管の検知を高精度に信頼性高く行
えるという高かがある。かくして、本発明は、ガス管や
水道管等の埋設管の掘削工事の効率化が可能になると同
時に、誤掘削による埋設管の損傷による事故の発生を未
然に防ぐことができるようになり、安全面並びに経済面
に於いて多大なる効果を奏する。(Effects of the Invention) As described above, the present invention allows an alternating current to be passed directly or indirectly to a buried underground pipe having electrical conductivity, and the underground pipe is detected by the magnetic field created by the alternating current on the ground surface. In the method of Since the magnetic field distributions are compared, it is possible to know the extent of the influence of underground currents, judge the reliability of the position of the buried pipe calculated based on the respective magnetic field distributions, and also check the frequency By calculating the position of the buried pipe from the magnetic field distribution closest to the cylindrical magnetic field distribution, it is possible to detect the buried pipe with high accuracy and reliability. Thus, the present invention makes it possible to improve the efficiency of excavation work for buried pipes such as gas pipes and water pipes, and at the same time to prevent accidents caused by damage to buried pipes due to incorrect excavation, thereby improving safety. It has great effects both in terms of economics and economics.
第１図は、地中電流の分布及びその周波数特性を測定す
るための測定系の模式的説明図、第２図は第１図の測定
結果を示す説明図、第３図（ａ）、（ｂ）は第１図の測
定時に於ける地表上の交流磁場分布の測定結果を示す説
明図、第４図は測定した磁場分布の、円筒状磁場分布か
らのずれを判断する方法の一例を示す説明図である。第
５図（ａ）（ｂ）及び第６図（ａ）、（ｂ）は従来構成
の系統説明図である。
符号１・・・送信器、２・・・埋設管、３・・・地表、
４・・・露出部、５・・・アース捧、６・・地中電流、
７，７′・・・地電位測定棒、８・・・交流電圧計。Fig. 1 is a schematic explanatory diagram of a measurement system for measuring the distribution of underground current and its frequency characteristics, Fig. 2 is an explanatory diagram showing the measurement results of Fig. 1, and Fig. 3 (a), ( b) is an explanatory diagram showing the measurement results of the alternating current magnetic field distribution on the earth's surface during the measurement of Fig. 1, and Fig. 4 shows an example of a method for determining the deviation of the measured magnetic field distribution from the cylindrical magnetic field distribution. It is an explanatory diagram. FIGS. 5(a) and 6(b) and FIGS. 6(a) and 6(b) are system explanatory diagrams of conventional configurations. Code 1... Transmitter, 2... Buried pipe, 3... Ground surface,
4...Exposed part, 5...Earth connection, 6...Underground current,
7, 7'...Earth potential measuring rod, 8...AC voltmeter.
Claims (6)
接または間接的に交流電流を流し、それが地表上に作る
磁場により、該埋設管を検知する方法に於いて、該埋設
管には、異なった周波数の複数の交流電流を、同時また
は時分割に流して、それらが地表上に作る複数の周波数
の交流磁場の分布を、同時または時分割に測定し、それ
らの磁場分布を比較することにより、夫々の磁場分布に
基づいて算出した埋設管の位置の信頼性を判断すること
を特徴とする埋設管の検知方法(1) In the method of detecting the underground pipe by directly or indirectly passing an alternating current through the electrically conductive underground pipe and detecting the underground pipe by the magnetic field created by the alternating current on the ground surface, In this method, multiple alternating currents of different frequencies are passed simultaneously or in a time-division manner, and the distribution of alternating current magnetic fields of multiple frequencies that they create on the earth's surface is measured simultaneously or in a time-division manner. A buried pipe detection method characterized by determining the reliability of the positions of buried pipes calculated based on respective magnetic field distributions by comparing them.
接または間接的に交流電流を流し、それが地表上に作る
磁場により、該埋設管を検知する方法に於いて、該埋設
管には、異なった周波数の複数の交流電流を、同時また
は時分割に流して、それらが地表上に作る複数の周波数
の交流磁場の分布を、同時または時分割に測定し、それ
らの磁場分布を比較して、最も円筒状磁場分布に近い磁
場分布から埋設管の位置を算出することを特徴とする埋
設管の検知方法(2) In the method of detecting the underground pipe by directly or indirectly passing an alternating current through the electrically conductive underground pipe and detecting the underground pipe by the magnetic field created by the alternating current on the ground surface, In this method, multiple alternating currents of different frequencies are passed simultaneously or in a time-division manner, and the distribution of alternating current magnetic fields of multiple frequencies that they create on the earth's surface is measured simultaneously or in a time-division manner. A buried pipe detection method characterized by calculating the position of the buried pipe from a magnetic field distribution that is closest to a cylindrical magnetic field distribution by comparison.
周波数の交流磁場の分布の比較は、磁場の最大値が一致
するように正規化して行うことを特徴とする埋設管の検
知方法(3) In the method described in item 1 or 2, the comparison of the distribution of alternating current magnetic fields of multiple frequencies is performed by normalizing the magnetic fields so that the maximum values match. Detection method
円筒状磁場分布からのずれは、地表上の複数の位置で測
定した磁場の方向を法線とする複数の面が互いに交差す
る線のバラツキ具合により判断することを特徴とする埋
設管の検知方法(4) In the method described in paragraph 2, the deviation of the measured magnetic field distribution from the cylindrical magnetic field distribution means that multiple planes whose normals are the direction of the magnetic field measured at multiple positions on the earth's surface intersect with each other. A buried pipe detection method characterized by determining based on the degree of dispersion of the line.
円筒状磁場分布からのずれは、水平方向の各位置に於け
る水平方向磁場成分と垂直方向磁場成分の比が、位置に
対して直線的に変化するかどうかを測定して判断するこ
とを特徴とする埋設管の検知方法(5) In the method described in item 2, the deviation of the measured magnetic field distribution from the cylindrical magnetic field distribution means that the ratio of the horizontal magnetic field component to the vertical magnetic field component at each horizontal position is A buried pipe detection method characterized by measuring and determining whether or not there is a linear change in the
円筒状磁場分布からのずれは、水平方向の各位置に於け
る水平方向または垂直方向の磁場成分の絶対値が、ある
位置に対して線対称であるかどうかを測定して判断する
ことを特徴とする埋設管の検知方法(6) In the method described in item 2, the deviation of the measured magnetic field distribution from the cylindrical magnetic field distribution means that the absolute value of the horizontal or vertical magnetic field component at each horizontal position is A buried pipe detection method characterized by measuring and determining whether or not it is symmetrical with respect to a line.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63171200A JPH0221289A (en) | 1988-07-09 | 1988-07-09 | Detection of buried pipe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63171200A JPH0221289A (en) | 1988-07-09 | 1988-07-09 | Detection of buried pipe |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0221289A true JPH0221289A (en) | 1990-01-24 |
| JPH0555833B2 JPH0555833B2 (en) | 1993-08-18 |
Family
ID=15918875
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63171200A Granted JPH0221289A (en) | 1988-07-09 | 1988-07-09 | Detection of buried pipe |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0221289A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05192314A (en) * | 1991-09-03 | 1993-08-03 | General Electric Co <Ge> | Tracking system for pursuing position and direction of apparatus in radio frequency electromagnetic field |
| JPH05245129A (en) * | 1991-12-30 | 1993-09-24 | Hamamatsu Photonics Kk | Diagnostic device |
| JPH06214043A (en) * | 1993-01-13 | 1994-08-05 | Kyushu Denki Kensetsu Koji Kk | Method for detecting underground buried circuit position |
| US8729901B2 (en) | 2009-07-06 | 2014-05-20 | Merlin Technology, Inc. | Measurement device and associated method for use in frequency selection for inground transmission |
| JP2016191627A (en) * | 2015-03-31 | 2016-11-10 | 大阪瓦斯株式会社 | Transmission signal setting method for detecting buried metal and detection device using setting method |
| US9739140B2 (en) | 2014-09-05 | 2017-08-22 | Merlin Technology, Inc. | Communication protocol in directional drilling system, apparatus and method utilizing multi-bit data symbol transmission |
| US10378338B2 (en) | 2017-06-28 | 2019-08-13 | Merlin Technology, Inc. | Advanced passive interference management in directional drilling system, apparatus and methods |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS629286A (en) * | 1985-07-05 | 1987-01-17 | Tokyo Gas Co Ltd | Method and device for detecting underground installation |
| JPS62297776A (en) * | 1986-06-17 | 1987-12-24 | Nec Corp | Position detecting method for buried conductor |
| JPS6335978U (en) * | 1986-08-26 | 1988-03-08 | ||
| JPH01123185A (en) * | 1987-11-06 | 1989-05-16 | Tokyo Gas Co Ltd | Method for magnetically detecting position of ground embedded object |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3123608C2 (en) * | 1981-06-13 | 1985-01-10 | Standard Elektrik Lorenz Ag, 7000 Stuttgart | Electrophotographic recording material |
-
1988
- 1988-07-09 JP JP63171200A patent/JPH0221289A/en active Granted
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS629286A (en) * | 1985-07-05 | 1987-01-17 | Tokyo Gas Co Ltd | Method and device for detecting underground installation |
| JPS62297776A (en) * | 1986-06-17 | 1987-12-24 | Nec Corp | Position detecting method for buried conductor |
| JPS6335978U (en) * | 1986-08-26 | 1988-03-08 | ||
| JPH01123185A (en) * | 1987-11-06 | 1989-05-16 | Tokyo Gas Co Ltd | Method for magnetically detecting position of ground embedded object |
Cited By (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05192314A (en) * | 1991-09-03 | 1993-08-03 | General Electric Co <Ge> | Tracking system for pursuing position and direction of apparatus in radio frequency electromagnetic field |
| JP2735747B2 (en) * | 1991-09-03 | 1998-04-02 | ゼネラル・エレクトリック・カンパニイ | Tracking and imaging system |
| JPH05245129A (en) * | 1991-12-30 | 1993-09-24 | Hamamatsu Photonics Kk | Diagnostic device |
| JPH06214043A (en) * | 1993-01-13 | 1994-08-05 | Kyushu Denki Kensetsu Koji Kk | Method for detecting underground buried circuit position |
| US10520536B2 (en) | 2009-07-06 | 2019-12-31 | Merlin Technology Inc. | Apparatus for predicting a maximum operational depth for an underground drilling procedure and method |
| US20170350930A1 (en) | 2009-07-06 | 2017-12-07 | Merlin Technology Inc. | Measurement device and associated method for use in frequency selection for inground transmission |
| US8729901B2 (en) | 2009-07-06 | 2014-05-20 | Merlin Technology, Inc. | Measurement device and associated method for use in frequency selection for inground transmission |
| US11802900B2 (en) | 2009-07-06 | 2023-10-31 | Merlin Technology Inc. | Portable device with removably attachable measuring leg |
| US10598712B2 (en) | 2009-07-06 | 2020-03-24 | Merlin Technology Inc. | Portable device with electromagnetic noise measurement for inground transmitter frequency selection |
| US11320474B2 (en) | 2009-07-06 | 2022-05-03 | Merlin Technology Inc. | Portable device for noise measurement at locations along a path to determine one or more indications |
| US11047896B2 (en) | 2009-07-06 | 2021-06-29 | Merlin Technology Inc. | Portable device with electromagnetic noise measurement at multiple frequencies |
| US9739140B2 (en) | 2014-09-05 | 2017-08-22 | Merlin Technology, Inc. | Communication protocol in directional drilling system, apparatus and method utilizing multi-bit data symbol transmission |
| US11230921B2 (en) | 2014-09-05 | 2022-01-25 | Merlin Technology, Inc. | Communication protocol in directional drilling system, apparatus and method utilizing multi-bit data symbol transmission |
| JP2016191627A (en) * | 2015-03-31 | 2016-11-10 | 大阪瓦斯株式会社 | Transmission signal setting method for detecting buried metal and detection device using setting method |
| US10378338B2 (en) | 2017-06-28 | 2019-08-13 | Merlin Technology, Inc. | Advanced passive interference management in directional drilling system, apparatus and methods |
| US11008856B2 (en) | 2017-06-28 | 2021-05-18 | Merlin Technology, Inc. | Advanced passive interference management in directional drilling system, apparatus and methods |
| US11352876B2 (en) | 2017-06-28 | 2022-06-07 | Merlin Technology, Inc. | Advanced passive interference management in directional drilling system, apparatus and methods |
| US11613990B2 (en) | 2017-06-28 | 2023-03-28 | Merlin Technology, Inc. | Advanced passive interference management in directional drilling system, apparatus and methods |
| US10598007B2 (en) | 2017-06-28 | 2020-03-24 | Merlin Technology, Inc. | Advanced passive interference management in directional drilling system, apparatus and methods |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0555833B2 (en) | 1993-08-18 |
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