JP6262640B2 - Lower branch rod deterioration measuring instrument and lower branch rod deterioration measuring method - Google Patents

Lower branch rod deterioration measuring instrument and lower branch rod deterioration measuring method Download PDF

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JP6262640B2
JP6262640B2 JP2014245774A JP2014245774A JP6262640B2 JP 6262640 B2 JP6262640 B2 JP 6262640B2 JP 2014245774 A JP2014245774 A JP 2014245774A JP 2014245774 A JP2014245774 A JP 2014245774A JP 6262640 B2 JP6262640 B2 JP 6262640B2
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lower branch
branch rod
iron core
deterioration
electromagnetic coil
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JP2016109510A (en
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水沼　守
守 水沼
香織 根岸
香織 根岸
孝 澤田
孝 澤田
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Nippon Telegraph and Telephone Corp
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Description

本発明は、下部支線ロッドの劣化測定器、および、下部支線ロッドの劣化測定方法に関する。   The present invention relates to a degradation measuring device for a lower branch rod and a degradation measuring method for a lower branch rod.

電柱等の構造物を補助的に支持するための鋼鉄製の支線を地中に埋設する方法がある。支線は、地上部の上部支線と、地中部の下部支線に分けることができる。そして、この下部支線には、地中に埋設された打込アンカーと接続するためのロッド（下部支線ロッド）が用いられることが多い。この下部支線ロッドの下方部分は、地中に埋設されていることから、目視で劣化状況を把握するのが困難であった。   There is a method of burying a steel branch line for supporting a structure such as a utility pole in the ground. The branch line can be divided into an upper branch line in the ground part and a lower branch line in the underground part. And the rod (lower branch rod) for connecting with the driving anchor embed | buried under the ground is often used for this lower branch line. Since the lower part of the lower branch rod is buried in the ground, it is difficult to visually grasp the deterioration state.

これまでは、下部支線ロッドの劣化状況を知りたい場合、下部支線ロッド付近の埋設土を掘削して点検する必要があり、設備を使用しながらの点検は困難であった。さらに、掘削には道路の使用許可や掘削作業等が必要であり、大がかりな作業が必要であった。そこで、超音波等により、下部支線ロッド付近を掘削せずに劣化状況を把握する方法も試みられている。   In the past, when it was desired to know the deterioration status of the lower branch rod, it was necessary to excavate and inspect the buried soil near the lower branch rod, which was difficult to check while using the equipment. Furthermore, excavation requires permission for use of the road, excavation work, etc., and extensive work is required. Then, the method of grasping | ascertaining a deterioration condition without excavating the lower branch rod vicinity by an ultrasonic wave etc. is also tried.

庄司他、「地中埋設の円柱形ロッドにおけるガイド波の減衰特性」、第20回超音波による非破壊評価シンポジウム（2013.1.28〜29）講演論文集、日本非破壊検査協会、2013年Shoji et al., “Attenuation characteristics of guide waves in underground cylindrical rods”, Proc. Of the 20th Symposium on Nondestructive Evaluation by Ultrasound (2013.1.28-29), Japan Nondestructive Inspection Association, 2013 Agilent Technologies、インピーダンス測定ハンドブック（2003年11月版）、[online]、[平成26年11月26日検索]、インターネット<URL：http://literature.cdn.keysight.com/litweb/pdf/5950-3000JA.pdf>Agilent Technologies, Impedance Measurement Handbook (November 2003 edition), [online], [Search on November 26, 2014], Internet <URL: http://literature.cdn.keysight.com/litweb/pdf/5950 -3000JA.pdf>

しかし、超音波を用いる方法は、地中部における超音波の減衰が大きく、下部支線ロッドの劣化状況を正確に把握できない。また、下部支線ロッドの劣化状況の把握のためには、下部支線ロッドの減肉等についても定量的な把握が必要となる場合もあるが、上記のような超音波の減衰の問題もあり、定量的な把握が難しい。そこで、本発明は、前記した問題を解決し、下部支線ロッド付近の埋設土を掘削することなく、地中部の下部支線ロッドの減肉による劣化状況を定量的に把握することを課題とする。   However, in the method using ultrasonic waves, the attenuation of ultrasonic waves in the underground part is large, and the deterioration state of the lower branch rod cannot be accurately grasped. In addition, in order to grasp the deterioration status of the lower branch rod, it may be necessary to quantitatively grasp the thinning of the lower branch rod, etc., but there is a problem of attenuation of the ultrasonic wave as described above, Difficult to grasp quantitatively. Then, this invention solves the above-mentioned problem and makes it a subject to grasp | ascertain quantitatively the deterioration condition by the thinning of the lower branch rod of an underground part without excavating the buried soil near a lower branch rod.

前記した課題を解決するため、本発明は、構造物を支持するために地中に埋設して固定する鋼鉄製の下部支線ロッドの劣化測定器であって、前記下部支線ロッドの側面に密着させて地中に打設貫入したときに、地上部分に位置する場所に電磁コイルが巻き付けられた鉄芯で、前記鉄芯の前記下部支線ロッドに接する側の面のうち、前記鉄芯の両端に位置する領域以外に樹脂板が形成された前記鉄芯を備えることを特徴とする。   In order to solve the above-described problems, the present invention provides a deterioration measuring instrument for a steel lower branch rod that is buried and fixed in the ground to support a structure, and is closely attached to a side surface of the lower branch rod. When the iron core is wound into the ground, an electromagnetic core is wound around a location located on the ground portion, and the surface of the iron core on the side in contact with the lower branch rod is attached to both ends of the iron core. It has the said iron core in which the resin board was formed in the area | region other than the area | region located.

本発明によれば、下部支線ロッドの付近の埋設土を掘削することなく、地中部の下部支線ロッドの減肉による劣化状況を定量的に把握することができる。   According to the present invention, it is possible to quantitatively grasp the deterioration state due to the thinning of the lower branch rod in the underground without excavating the buried soil near the lower branch rod.

図１は、鉄芯の打設状態を説明する図である。FIG. 1 is a diagram for explaining the iron core placing state. 図２は、下部支線ロッドの劣化状況の測定手順を示すフローチャートである。FIG. 2 is a flowchart showing a procedure for measuring the deterioration state of the lower branch rod. 図３は、鉄芯を含む劣化測定システムの構成例を示す図である。FIG. 3 is a diagram illustrating a configuration example of a deterioration measurement system including an iron core. 図４は、第１の実施形態の鉄芯の上面図、側面図および断面図を示す図である。FIG. 4 is a diagram illustrating a top view, a side view, and a cross-sectional view of the iron core according to the first embodiment. 図５は、第２の実施形態の鉄芯の上面図、側面図および断面図を示す図である。FIG. 5 is a diagram illustrating a top view, a side view, and a cross-sectional view of the iron core according to the second embodiment. 図６は、鉄芯のインダクタンスの測定結果を示すグラフである。FIG. 6 is a graph showing measurement results of the iron core inductance.

以下、図面を参照しながら、本発明を実施するための形態（実施形態）を第１の実施形態および第２の実施形態に分けて説明する。なお、本発明は、本実施形態に限定されない。   DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments (embodiments) for carrying out the present invention will be described by dividing them into a first embodiment and a second embodiment with reference to the drawings. Note that the present invention is not limited to this embodiment.

（第１の実施形態）
まず、図１および図２を参照して、本発明の第１の実施形態の鉄芯２０を用いた電柱の下部支線ロッド１０の劣化状況の測定手順について説明する。ここでは下部支線ロッド１０の外径を測定することで、下部支線ロッド１０の劣化状況を測定する場合を例に説明する。 (First embodiment)
First, with reference to FIG. 1 and FIG. 2, the measurement procedure of the deterioration condition of the lower branch rod 10 of the utility pole using the iron core 20 of the 1st Embodiment of this invention is demonstrated. Here, the case where the deterioration condition of the lower branch rod 10 is measured by measuring the outer diameter of the lower branch rod 10 will be described as an example.

下部支線ロッド１０は、電柱等の構造物を補助的に支持するために地中に埋設して固定される鋼鉄製のロッドである。例えば、図１に示すように、電柱には支線がつながれ、この支線は下部支線ロッド１０により地中の打込アンカーにつながれる。この下部支線ロッド１０の材料は、例えば、ＳＳ４００等である。この下部支線ロッド１０は、ループ部と、このループ部に取り付けられたリングとを備える。リングには、電柱の支線が巻きつけられており、これにより下部支線ロッド１０のループ部経由で地中の打込アンカーと繋がれ、電柱が支持されることになる。   The lower branch rod 10 is a steel rod that is buried and fixed in the ground in order to support a structure such as a utility pole in an auxiliary manner. For example, as shown in FIG. 1, a branch line is connected to the utility pole, and this branch line is connected to a driving anchor in the ground by a lower branch line rod 10. The material of the lower branch rod 10 is, for example, SS400. The lower branch rod 10 includes a loop portion and a ring attached to the loop portion. A branch line of a utility pole is wound around the ring, and this connects to the driving anchor in the ground via the loop portion of the lower branch rod 10 to support the utility pole.

このような状態において、下部支線ロッド１０の外径は以下のようにして測定される。まず、下部支線ロッド１０の外径センサとして用いる鉄芯２０（詳細は後記）を、下部支線ロッド１０に沿わせて、ハンマ等で地中に打設する（図２のＳ１）。このとき、鉄芯２０は、下部支線ロッド１０のループ部およびリングから離れないように打設する。そして、鉄芯２０の上端部が下部支線ロッド１０のループ部の直下の位置に来た段階で打設を終了する。そして、鉄芯２０に巻きつけられた電磁コイル２１に電流を流し、インダクタンスの値を測定する（Ｓ２：インダクタンス測定）。そして、測定されたインダクタンスの値に基づき下部支線ロッド１０の断面積Ｓを計算し（Ｓ３）、計算された断面積Ｓの値をもとに下部支線ロッド１０の外径２ｒを計算する（Ｓ４）。このようにすることで、下部支線ロッド１０の外径が劣化によりどの程度細くなっているかを測定することができる。なお、ここでの下部支線ロッド１０の断面積Ｓおよび外径２ｒの計算の詳細については後記する。   In such a state, the outer diameter of the lower branch rod 10 is measured as follows. First, an iron core 20 (described later in detail) used as an outer diameter sensor of the lower branch rod 10 is placed in the ground with a hammer or the like along the lower branch rod 10 (S1 in FIG. 2). At this time, the iron core 20 is placed so as not to leave the loop portion and the ring of the lower branch rod 10. Then, when the upper end portion of the iron core 20 comes to a position immediately below the loop portion of the lower branch rod 10, the placement is finished. And an electric current is sent through the electromagnetic coil 21 wound around the iron core 20, and the value of an inductance is measured (S2: inductance measurement). Then, the sectional area S of the lower branch rod 10 is calculated based on the measured inductance value (S3), and the outer diameter 2r of the lower branch rod 10 is calculated based on the calculated sectional area S (S4). ). By doing in this way, it is possible to measure how thin the outer diameter of the lower branch rod 10 is due to deterioration. Details of calculation of the cross-sectional area S and the outer diameter 2r of the lower branch rod 10 will be described later.

次に、鉄芯２０について、図３および図４を参照しながら詳細に説明する。図３は、鉄芯２０を含む測定システム（劣化測定器）の構成例を示す図である。なお、図３において、鉄芯２０は地中への打設が完了した状態を示す。鉄芯２０による下部支線ロッド１０の外径の測定範囲は、下部支線ロッド１０のループ部の下から、鉄芯２０の全長（５００ｍｍ程度）分である。   Next, the iron core 20 will be described in detail with reference to FIGS. 3 and 4. FIG. 3 is a diagram illustrating a configuration example of a measurement system (deterioration measuring device) including the iron core 20. In addition, in FIG. 3, the iron core 20 shows the state which has been placed in the ground. The measurement range of the outer diameter of the lower branch rod 10 by the iron core 20 is the entire length (about 500 mm) of the iron core 20 from below the loop portion of the lower branch rod 10.

図３に示すように、鉄芯２０には、当該鉄芯２０が地中に打設されたときの地上部分となる位置に電磁コイル２１が巻きつけられている。電磁コイル２１の位置は、例えば、鉄芯２０の上端部から５０〜１００ｍｍ程度の位置であり、電磁コイル２１の長さは、例えば、５０ｍｍ程度である。なお、電磁コイル２１の巻線は、直径０．１５ｍｍの銅線を用いたとして、素線は７ｍ程度である。電磁コイル２１のコイル巻数は、例えば、２７５Ｔ程度である。   As shown in FIG. 3, an electromagnetic coil 21 is wound around the iron core 20 at a position that becomes a ground portion when the iron core 20 is driven into the ground. The position of the electromagnetic coil 21 is, for example, about 50 to 100 mm from the upper end of the iron core 20, and the length of the electromagnetic coil 21 is, for example, about 50 mm. In addition, the winding of the electromagnetic coil 21 is about 7 m, if the copper wire with a diameter of 0.15 mm is used. The number of coil turns of the electromagnetic coil 21 is, for example, about 275T.

また、この鉄芯２０には、当該鉄芯２０の両端が下部支線ロッド１０に接するように下部支線ロッド１０との接触面に樹脂板２２が形成されている。つまり、鉄芯２０の下部支線ロッド１０側の面のうち両端（上端部と下端部）に位置する領域は下部支線ロッド１０に接するが、それ以外の領域は下部支線ロッド１０に接しないよう樹脂板２２が貼り付けられている。   In addition, a resin plate 22 is formed on the contact surface with the lower branch rod 10 so that both ends of the iron core 20 are in contact with the lower branch rod 10. That is, the region located at both ends (upper end and lower end) of the surface of the iron core 20 on the lower branch rod 10 side is in contact with the lower branch rod 10, but the other regions are not in contact with the lower branch rod 10. A plate 22 is affixed.

図４の（ａ）は鉄芯２０の上面図を示し、（ｂ）は鉄芯２０の側面図を示し、（ｃ）は鉄芯２０のＸ−Ｘ´で切断した断面図を示す。なお、鉄芯２０の全長は、例えば、５００ｍｍ程度であり、太さは、例えば、１０ｍｍ×１０ｍｍ程度である。   4A shows a top view of the iron core 20, FIG. 4B shows a side view of the iron core 20, and FIG. 4C shows a cross-sectional view taken along the line XX ′ of the iron core 20. The total length of the iron core 20 is, for example, about 500 mm, and the thickness is, for example, about 10 mm × 10 mm.

図４の（ｂ）に示すように、鉄芯２０の下部支線ロッド１０側の面の上端部（符号２３）と下端部（符号２４）は下部支線ロッド１０に接するが、上端部と下端部以外の部分は接しないように樹脂板２２が貼り付けられている。なお、この上端部と下端部の長さは、それぞれ、８〜１０ｍｍ程度が好ましい。また、樹脂板２２の素材は、例えば、ポリ塩化ビニル（ＰＶＣ）等である。なお、このポリ塩化ビニルの比透磁率は、１．０である。また、鉄芯２０の下端部（符号２４）は地中への打設をしやすいよう、図４の（ｂ）に示すようなくさび状の形状が好ましい。さらに、鉄芯２０の両端の下部支線ロッド１０に接する面は、下部支線ロッド１０に密接するよう、例えば、図４（ｃ）や図３の符号２０１に示すように、下部支線ロッド１０の表面の形に合わせた形状とするのが好ましい。   As shown in FIG. 4B, the upper end (reference numeral 23) and the lower end (reference numeral 24) of the surface of the iron core 20 on the lower branch rod 10 side are in contact with the lower branch rod 10, but the upper end and the lower end. A resin plate 22 is affixed so as not to contact other portions. In addition, as for the length of this upper end part and a lower end part, about 8-10 mm is respectively preferable. The material of the resin plate 22 is, for example, polyvinyl chloride (PVC). The relative permeability of this polyvinyl chloride is 1.0. Further, the lower end portion (reference numeral 24) of the iron core 20 preferably has a wedge shape as shown in FIG. 4B so that it can be easily placed in the ground. Further, the surfaces of the iron core 20 that are in contact with the lower branch rod 10 are in close contact with the lower branch rod 10, for example, as shown by reference numeral 201 in FIG. 4C and FIG. 3, the surface of the lower branch rod 10. It is preferable to adopt a shape that matches the shape.

図３の説明に戻る。鉄芯２０の両端は下部支線ロッド１０に接し、その他の部分は樹脂板２２が挟まれているので下部支線ロッド１０に直接接しない。そのため、鉄芯２０の電磁コイル２１に通電すると、図３に示すような磁束が生じることになる。つまり、鉄芯２０と下部支線ロッド１０とをつなぐループ状の磁気回路が生じる。ここで、鉄芯２０と下部支線ロッド１０との間には磁力が働き、間隙（磁気回路）が閉じるように動作するので、鉄芯２０は下部支線ロッド１０に密着することになる。   Returning to the description of FIG. Both ends of the iron core 20 are in contact with the lower branch rod 10 and the other portions are not in direct contact with the lower branch rod 10 because the resin plate 22 is sandwiched. Therefore, when the electromagnetic coil 21 of the iron core 20 is energized, a magnetic flux as shown in FIG. 3 is generated. That is, a loop-shaped magnetic circuit connecting the iron core 20 and the lower branch rod 10 is generated. Here, a magnetic force acts between the iron core 20 and the lower branch rod 10 and operates so as to close the gap (magnetic circuit), so that the iron core 20 comes into close contact with the lower branch rod 10.

このような状態で、電磁コイル２１のインダクタンスの値を測定する。例えば、図３に示すように、電磁コイル２１にコモングラウンド、電源、アンプ、Ａ／Ｄ（アナログデジタル）コンバータ等を接続し、インピーダンスアナライザ３０等を用いてインダクタンスの値を測定する。なお、ここでのインダクタンスの測定には、例えば、自動平衡ブリッジ法等（非特許文献２参照）を用いる。そして、インピーダンスアナライザ３０により測定されたインダクタンスの値はコンピュータ４０に出力される。   In such a state, the inductance value of the electromagnetic coil 21 is measured. For example, as shown in FIG. 3, a common ground, a power source, an amplifier, an A / D (analog / digital) converter or the like is connected to the electromagnetic coil 21, and an inductance value is measured using an impedance analyzer 30 or the like. For example, the automatic balance bridge method (see Non-Patent Document 2) is used for the inductance measurement here. Then, the inductance value measured by the impedance analyzer 30 is output to the computer 40.

ここで、無限長ソレノイドにおけるインダクタンスＬは、鉄芯（この場合、下部支線ロッド１０）の透磁率μ、断面積Ｓ、電磁コイル２１のコイル巻数Ｎの二乗に比例し、以下の式（１）のように表される。   Here, the inductance L in the infinite length solenoid is proportional to the magnetic permeability μ of the iron core (in this case, the lower branch rod 10), the cross-sectional area S, and the square of the number of coil turns N of the electromagnetic coil 21, and the following equation (1) It is expressed as

Ｌ＝μＮ２Ｓ…式（１） L = μN 2 S (1)

なお、断面積Ｓは、下部支線ロッド１０の断面のうち最も細い部分（つまり、下部支線ロッド１０の劣化等により、最も細くくびれた部分）が反映される。したがって、コンピュータ４０は、上記の式（１）により、測定対象の下部支線ロッド１０の断面積Ｓを計算することで、下部支線ロッド１０の劣化等により最も細くなっている部分の太さを推測することができる。例えば、上記の式（１）により下部支線ロッド１０の断面積Ｓを計算し、下部支線ロッド１０の断面を円形と見なせば、下部支線ロッド１０の最も細くなっている部分の外径２ｒの値を推測することができる。   The cross-sectional area S reflects the narrowest portion of the cross section of the lower branch rod 10 (that is, the narrowest portion due to deterioration of the lower branch rod 10 or the like). Therefore, the computer 40 estimates the thickness of the thinnest part due to deterioration of the lower branch rod 10 or the like by calculating the cross-sectional area S of the lower branch rod 10 to be measured by the above equation (1). can do. For example, if the sectional area S of the lower branch rod 10 is calculated by the above formula (1) and the section of the lower branch rod 10 is regarded as a circle, the outer diameter 2r of the thinnest portion of the lower branch rod 10 is The value can be inferred.

このようにすることで、下部支線ロッド１０の付近の埋設土を掘削することなく、下部支線ロッド１０の劣化状況を定量的に把握することができる。   By doing in this way, the deterioration condition of the lower branch rod 10 can be grasped | ascertained quantitatively, without excavating the buried soil near the lower branch rod 10.

（第２の実施形態）
なお、上記の鉄芯２０の中心に送水管を設け、鉄芯２０ａの端部から高圧水を噴射させ、下端部に入り込んだ土砂を吹き飛ばすようにしてもよい。この場合の鉄芯２０ａの形状の例を図５に示す。図５の（ａ）は鉄芯２０ａの上面図を示し、（ｂ）は鉄芯２０ａの側面図を示し、（ｃ）は鉄芯２０ａをＡ−Ａ´で切断した断面図を示す。 (Second Embodiment)
In addition, a water pipe may be provided in the center of the iron core 20 so that high-pressure water is jetted from the end of the iron core 20a, and the earth and sand entering the lower end may be blown off. An example of the shape of the iron core 20a in this case is shown in FIG. 5A shows a top view of the iron core 20a, FIG. 5B shows a side view of the iron core 20a, and FIG. 5C shows a cross-sectional view of the iron core 20a cut along AA ′.

例えば、鉄芯２０ａは中心部に送水管２６を備え、鉄芯２０ａの下端部に排水口２７を備える。そして、鉄芯２０ａの上端部側から送水管２６経由で高圧水を通し、下端部の排水口２７から高圧水を噴射させることで、下端部に入り込んだ土砂を吹き飛ばす。このようにすることで、鉄芯２０ａと下部支線ロッド１０との間隙に土砂が入り込んでしまった場合でも、これを吹き飛ばし、鉄芯２０ａと下部支線ロッド１０と密着させることができる。その結果、鉄芯２０ａの電磁コイル２１の正確なインダクタンスの値を得ることができる。   For example, the iron core 20a includes a water pipe 26 at the center, and a drain port 27 at the lower end of the iron core 20a. And high pressure water is passed through the water pipe 26 from the upper end side of the iron core 20a, and the high pressure water is jetted from the drain port 27 at the lower end portion, thereby blowing away the earth and sand entering the lower end portion. By doing in this way, even when earth and sand have entered into the gap between the iron core 20a and the lower branch rod 10, this can be blown away and brought into close contact with the iron core 20a and the lower branch rod 10. As a result, an accurate inductance value of the electromagnetic coil 21 of the iron core 20a can be obtained.

（その他の実施形態）
また、コンピュータ４０は、鉄芯２０，２０ａの電磁コイル２１のインダクタンスの測定値を複数回取得し、これに基づき、インダクタンスの値を補正して、下部支線ロッド１０の外径を計算してもよい。例えば、事前に、下部支線ロッド１０の周囲の環境（例えば、下部支線ロッド１０の埋設場所付近の土壌や大気の湿度、土壌の含水率、粒度、粘度、硬度等）や、境界条件（例えば、土壌の種類等による物性値、下部支線ロッド１０の表面の腐食状態等）、鉄芯２０，２０ａと下部支線ロッド１０の密着状態等、様々な条件下での電磁コイル２１のインダクタンスの値の実験値のデータベースを用意しておく。そして、コンピュータ４０は、インピーダンスアナライザ３０により複数のインダクタンスの値を得ると、上記のデータベースに基づき、インダクタンスの値を修正し、この修正した値をもとに、上記の式（１）により、下部支線ロッド１０の外径２ｒを計算する。 (Other embodiments)
Further, the computer 40 obtains the measured value of the inductance of the electromagnetic coil 21 of the iron cores 20 and 20a a plurality of times, and corrects the inductance value based on this value to calculate the outer diameter of the lower branch rod 10. Good. For example, in advance, the environment around the lower branch rod 10 (for example, the soil and atmospheric humidity near the burial site of the lower branch rod 10, moisture content of the soil, particle size, viscosity, hardness, etc.) and boundary conditions (for example, Experiments on the inductance value of the electromagnetic coil 21 under various conditions such as the physical property value depending on the type of soil, the corrosion state of the surface of the lower branch rod 10), the contact state between the iron cores 20, 20 a and the lower branch rod 10 Prepare a database of values. When the computer 40 obtains a plurality of inductance values by the impedance analyzer 30, the computer 40 corrects the inductance values based on the database, and based on the corrected values, The outer diameter 2r of the branch rod 10 is calculated.

このようにすることで、下部支線ロッド１０の周囲の環境や、境界条件の相違、鉄芯２０，２０ａと下部支線ロッド１０の密着状態の違い等が原因となって生じるインダクタンスの測定値のばらつきを補正することができる。その結果、下部支線ロッド１０の外径について、より正確に計算することができる。   By doing in this way, the dispersion | variation in the measured value of the inductance produced by the surrounding environment of the lower branch rod 10, the difference in boundary conditions, the difference in the contact | adherence state of the iron cores 20 and 20a, and the lower branch rod 10 etc. Can be corrected. As a result, the outer diameter of the lower branch rod 10 can be calculated more accurately.

（実験結果）
以下に、本実施形態の鉄芯２０のインダクタンスの値の測定結果と、測定されたインダクタンスを用いた下部支線ロッド１０の外径の計算結果とを示す。 (Experimental result)
Below, the measurement result of the value of the inductance of the iron core 20 of this embodiment and the calculation result of the outer diameter of the lower branch rod 10 using the measured inductance are shown.

ここでの鉄芯２０の材料は、下部支線ロッド１０の材料と同じＳＳ４００を使用した。鉄芯２０の透磁率μｓは、μｓ＝０．４３ｍＨ／ｍ（比透磁率μは、μ＝３４１。真空の透磁率μ０＝４π×１０−７Ｈ／ｍ＝１．２６×１０−６Ｈ／ｍを掛けて、μ＝μ０μｓ＝１．２６３４１×１０−６Ｈ／ｍ×３４１＝０．４３ｍＨ／ｍ）。鉄芯２０の電磁コイル２１のコイル巻数Ｎは２７５Ｔであった。このような条件下において、インピーダンスアナライザ３０で、鉄芯２０のインピーダンスＺを測定したところ、図６のグラフに示す値が測定された。 The material of the iron core 20 here was the same SS400 as the material of the lower branch rod 10. The permeability μ s of the iron core 20 is μ s = 0.43 mH / m (the relative permeability μ is μ = 341. The vacuum permeability μ 0 = 4π × 10 −7 H / m = 1.26 × 10 Multiply by −6 H / m, μ = μ 0 μs = 1.263341 × 10 −6 H / m × 341 = 0.43 mH / m). The coil winding number N of the electromagnetic coil 21 of the iron core 20 was 275T. Under such conditions, when the impedance Z of the iron core 20 was measured by the impedance analyzer 30, the values shown in the graph of FIG. 6 were measured.

ここでインピーダンスＺは、Ｚ＝２πｆＬなので、インダクタンスＬの値は、図６のグラフの低周波部分（１０〜１０００Ｈｚ）のグラフの傾き＝２πＬから求めることができる。   Here, since the impedance Z is Z = 2πfL, the value of the inductance L can be obtained from the slope = 2πL of the graph of the low frequency portion (10 to 1000 Hz) of the graph of FIG.

つまり、図６の低周波部分（１０〜１０００Ｈｚ）のグラフの傾き（２πＬ）＝０．０１ｋΩ／１０００Ｈｚなので、インダクタンスＬ＝１．５９×１０−３［Ω・ｓ］＝１．５９［ｍＨ］≒２[ｍＨ]となる。 That is, since the slope (2πL) of the graph of the low frequency portion (10 to 1000 Hz) in FIG. 6 is 0.01 kΩ / 1000 Hz, the inductance L = 1.59 × 10 −3 [Ω · s] = 1.59 [mH]. ≒ 2 [mH].

そして、このインダクタンスＬの値を、前記した式（１）に代入すると、Ｓ＝Ｌ／（μＮ２）＝２ｍＨ／（０．４３ｍＨ×２５０×２５０）＝７．４４×１０−５となる。よって、下部支線ロッド１０の外径（半径ｒ）は、ｒ＝√（Ｓ／π）＝０．００４９ｍ＝４．９ｍｍとなる。 Then, when the value of the inductance L is substituted into the above equation (1), S = L / (μN 2 ) = 2 mH / (0.43 mH × 250 × 250) = 7.44 × 10 −5 . Therefore, the outer diameter (radius r) of the lower branch rod 10 is r = √ (S / π) = 0.499m = 4.9 mm.

１０ 下部支線ロッド
２０，２０ａ 鉄芯
２１ 電磁コイル
２２ 樹脂板
２６ 送水管
２７ 排水口
３０ インピーダンスアナライザ
４０ コンピュータ DESCRIPTION OF SYMBOLS 10 Lower branch rod 20, 20a Iron core 21 Electromagnetic coil 22 Resin board 26 Water pipe 27 Drain outlet 30 Impedance analyzer 40 Computer

Claims (5)

構造物を支持するために地中に埋設して固定する鋼鉄製の下部支線ロッドの劣化測定器であって、
前記下部支線ロッドの側面に密着させて地中に打設貫入したときに、地上部分に位置する場所に電磁コイルが巻き付けられた鉄芯で、前記鉄芯の前記下部支線ロッドに接する側の面のうち、前記鉄芯の両端に位置する領域以外に樹脂板が形成された前記鉄芯を備えることを特徴とする下部支線ロッドの劣化測定器。 A deterioration measuring instrument for a steel lower branch rod that is buried and fixed in the ground to support a structure,
An iron core in which an electromagnetic coil is wound around a place located on the ground portion when it is placed in close contact with the side surface of the lower branch rod, and the surface of the iron core on the side in contact with the lower branch rod Among these, the deterioration measuring instrument for a lower branch rod, comprising the iron core on which a resin plate is formed in a region other than regions located at both ends of the iron core. 前記下部支線ロッドの劣化測定器は、さらに、
通電状態となった前記電磁コイルを通じて、前記鉄芯と前記下部支線ロッドとからなるループ状の磁気回路のインダクタンスの値を測定する手段を備えることを特徴とする請求項１に記載の下部支線ロッドの劣化測定器。 The deterioration measuring instrument for the lower branch rod is further,
2. The lower branch rod according to claim 1, further comprising means for measuring an inductance value of a loop-shaped magnetic circuit composed of the iron core and the lower branch rod through the energized electromagnetic coil. Degradation measuring instrument. 前記鉄芯は、さらに、
前記鉄芯の内部に送水管と、前記鉄芯が打設貫入されたときに地中に埋没する方の端に前記送水管の排水口とを備えることを特徴とする請求項１または２に記載の下部支線ロッドの劣化測定器。 The iron core is further
The water supply pipe is provided inside the iron core, and a drain outlet of the water supply pipe is provided at an end of the iron core that is buried in the ground when the iron core is inserted and penetrated. Deterioration measuring instrument for lower branch rod as described. 構造物を支持するために地中に埋設して固定する鋼鉄製の下部支線ロッドの劣化測定方法であって、
前記下部支線ロッドの側面に密着させて地中に打設貫入したときに、地上部分に位置する場所に電磁コイルが巻き付けられた鉄芯で、前記鉄芯の前記下部支線ロッドに接する側の面のうち、前記鉄芯の両端に位置する領域以外に樹脂板が形成された前記鉄芯を、前記下部支線ロッドの側面に密着させて地中に打設貫入するステップと、
前記電磁コイルを通電状態にするステップと、
通電状態となった前記電磁コイルを通じて、前記鉄芯と前記下部支線ロッドとからなるループ状の磁気回路のインダクタンスの値を測定するステップと、
前記測定したインダクタンスの値をもとに、前記下部支線ロッドの断面積を計算するステップと、
を含んだことを特徴とする下部支線ロッドの劣化測定方法。 A method for measuring deterioration of a steel lower branch rod that is buried and fixed in the ground to support a structure,
An iron core in which an electromagnetic coil is wound around a place located on the ground portion when it is placed in close contact with the side surface of the lower branch rod, and the surface of the iron core on the side in contact with the lower branch rod Among them, the step of placing and penetrating the iron core formed with a resin plate other than the regions located at both ends of the iron core in close contact with the side surface of the lower branch rod,
Bringing the electromagnetic coil into an energized state;
Measuring the value of the inductance of a loop-shaped magnetic circuit composed of the iron core and the lower branch rod through the electromagnetic coil that is energized;
Based on the measured inductance value, calculating a cross-sectional area of the lower branch rod;
The deterioration measuring method of the lower branch rod characterized by including. 前記測定されたインダクタンスの値を、既存の実験値をもとに補正するステップ
をさらに含んだことを特徴とする請求項４に記載の下部支線ロッドの劣化測定方法。 The method for measuring deterioration of a lower branch rod according to claim 4, further comprising a step of correcting the measured inductance value based on an existing experimental value.
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