JPH0551850B2 - - Google Patents
Info
- Publication number
- JPH0551850B2 JPH0551850B2 JP58070234A JP7023483A JPH0551850B2 JP H0551850 B2 JPH0551850 B2 JP H0551850B2 JP 58070234 A JP58070234 A JP 58070234A JP 7023483 A JP7023483 A JP 7023483A JP H0551850 B2 JPH0551850 B2 JP H0551850B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- amount
- probe
- ground
- subsidence
- 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.)
- Expired - Lifetime
Links
- 238000005259 measurement Methods 0.000 claims description 29
- 239000000523 sample Substances 0.000 claims description 24
- 238000001514 detection method Methods 0.000 claims description 23
- 238000000034 method Methods 0.000 claims description 20
- 239000004020 conductor Substances 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 230000005284 excitation Effects 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 230000008602 contraction Effects 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 229920003002 synthetic resin Polymers 0.000 description 2
- 239000000057 synthetic resin Substances 0.000 description 2
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007596 consolidation process Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000005674 electromagnetic induction Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000002513 implantation Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 230000005389 magnetism Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
Landscapes
- Testing Or Calibration Of Command Recording Devices (AREA)
Description
【発明の詳細な説明】
〔産業上の利用分野〕
この発明は、磁気を利用して地盤の深度別沈下
量を測定する方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of measuring the amount of subsidence of the ground at different depths using magnetism.
一般に、埋立て地盤や厚い盛土層においては、
地層の圧密や圧縮による沈下が生ずることは避け
難い現象であり、このために地表または地中の構
造物に大きな被害が生ずる事例は極めて多い。従
来、地盤の沈下現象を、単に地表面の沈下として
観測する方法が採用されていた。なるほど、地盤
の沈下現象の総量は結果的に地上に表れるのであ
るから、この総量を知る必要があるのであれば、
上記の方法は正しい。しかし、地下を構成してい
る各層の収縮量は、各層の土質特性や深度によつ
て一様ではない。したがつて、地下の各層におけ
る変形量を知ることは地盤沈下に対する予測や対
策を立てる上において非常に重要である。ところ
が、このような地盤の深度別沈下量測定は、上記
従来法ではできない。そこで、深度別沈下量測定
を可能とする方法として、二重管方式やアイソト
ープ方式が考案されたが、測定密度や精度等に関
して問題があつた。
Generally, in reclaimed ground or thick embankment layer,
Subsidence due to consolidation and compression of strata is an unavoidable phenomenon, and there are many cases in which this causes great damage to structures on the ground surface or underground. Conventionally, the method of observing ground subsidence phenomena was simply as the subsidence of the ground surface. I see, the total amount of ground subsidence appears on the ground, so if you need to know the total amount,
The above method is correct. However, the amount of contraction of each layer that makes up the underground is not uniform depending on the soil characteristics and depth of each layer. Therefore, knowing the amount of deformation in each underground layer is very important in predicting and taking countermeasures against ground subsidence. However, such measurement of ground subsidence by depth cannot be performed using the conventional method described above. Therefore, the double tube method and the isotope method were devised as methods to make it possible to measure the amount of subsidence at different depths, but there were problems with measurement density, accuracy, etc.
この発明者は、そのような問題を解消するた
め、電磁誘導現象を利用する方法を先に公表し
た。すなわち、次のような方法である。測定地点
に、不動点となる地層まで達するボーリング孔を
穿ち、不動点となる地層および所望の各深度にお
けるボーリング孔側壁面に金属製のリングを圧着
させる。測定時には、互いに逆接続された一対の
励磁コイルと電圧検出コイルとを、後者を前二者
の間に位置させるようして巻きつけた棒状のプロ
ーブを目盛付きのスチールテープでボーリング孔
内に垂下させる。この時、電圧検出コイルは地上
の電圧計と接続している。前記プローブがボーリ
ング孔内にあるリング内を通過するとき、電圧計
は、最初の励磁コイルと次の励磁コイルが通過す
る際に最大電圧値を検出し、２回の極大値の中間
点で最小電圧値を検出する。それは、逆接続され
た一対の励磁コイルが作り出す磁界が両コイルの
中間点で打ち消されているからである。このよう
にして、電圧計が最小値を示す時のスチールテー
プの目盛と不動点におけるスチールテープの目盛
との差を求めることによつて、不動点の上方に位
置する各リングの変位を測定するのである。しか
し、この方法によれば、ボーリング孔側壁面への
リングの取付けに手間がかるという問題があつ
た。 The inventor previously disclosed a method using electromagnetic induction phenomena to solve such problems. That is, the method is as follows. At the measurement point, a borehole is drilled that reaches the stratum that will be the fixed point, and a metal ring is crimped to the side wall of the borehole at each desired depth and the stratum that will be the fixed point. During measurement, a rod-shaped probe is wrapped around a pair of excitation coils and voltage detection coils that are connected in opposite directions, with the latter positioned between the former two, and is suspended in a borehole using a graduated steel tape. let At this time, the voltage detection coil is connected to the voltmeter on the ground. When the probe passes through the ring in the borehole, the voltmeter detects the maximum voltage value when the first excitation coil and the next excitation coil pass, and the minimum value at the midpoint between the two maximum values. Detect voltage value. This is because the magnetic fields produced by a pair of reversely connected excitation coils are canceled out at the midpoint between the two coils. In this way, the displacement of each ring located above the fixed point is measured by finding the difference between the steel tape scale when the voltmeter shows the minimum value and the steel tape scale at the fixed point. It is. However, this method has a problem in that it takes time and effort to attach the ring to the side wall surface of the borehole.
そこで、この発明は、測定が極めて簡単かつ容
易であり、測定結果の信頼性が高く、測定点を増
やす（多くする）ことも容易な地盤の深度別沈下
量測定方法を提供することを課題とする。
Therefore, an object of this invention is to provide a method for measuring the amount of ground subsidence by depth, which is extremely simple and easy to measure, has high reliability of measurement results, and can easily increase the number of measurement points. do.
前記課題を解決するため、この発明の地盤の深
度別沈下量測定方法では、沈下量を測定すべき地
盤に穿たれたボーリング孔における側壁面の深度
の異なる位置ごとに個々にマグネツト弾を打ち込
んでおいて、各マグネツト弾が作る磁界を、前記
ボーリング孔内に降下させた磁気測定用プローブ
により検出されて前記各マグネツト弾の基準レベ
ルからの位置を測定する操作を時間を隔てて行い
前記各マグネツト弾の位置変動量を調べることに
より、地盤中の前記各深度における沈下量を計測
するようにしている。
In order to solve the above problem, in the method of measuring the amount of subsidence by depth of the ground according to the present invention, magnetic bullets are individually fired at different depths of the side wall surface of a borehole drilled in the ground where the amount of subsidence is to be measured. Then, the magnetic field generated by each magnetic bullet is detected by a magnetic measurement probe lowered into the borehole, and the position of each magnetic bullet from a reference level is measured at intervals. By examining the amount of positional variation of the bullet, the amount of subsidence at each of the depths in the ground is measured.
そして、各マグネツト弾が作る磁界の検出は、
請求孔２にみるように、ブリツジ型磁気抵抗素子
２個を有してボーリング孔内に降ろされる磁界測
定用プローブと、バランス回路およびその出力を
検出する検流計を有する測定器と、前記ブリツジ
型磁気検出抵抗素子２個の出力をバランス回路に
伝える導線が内蔵されたケーブルとをそれぞれ備
え、前記ブリツジ型磁気抵抗素子２個は、それぞ
れの出力端子を共通とし、かつ磁界測定用プロー
ブがボーリング孔内を昇降するとき前記各マグネ
ツト弾のうちのひとつが作る同じ磁界に入る時期
が少しばかりずれ、しかも同一磁界内において逆
方向の出力が得られるようにプローブ内に配置さ
れている磁気検出装置を用いて行うことができ
る。 The detection of the magnetic field created by each magnetic bullet is
As shown in hole 2, a magnetic field measuring probe having two bridge-type magnetoresistive elements is lowered into the borehole, a measuring instrument having a balance circuit and a galvanometer for detecting its output, and the bridge The two bridge-type magnetoresistive elements each have a common output terminal, and the magnetic field measurement probe is connected to a boring cable. a magnetic detection device disposed within the probe so that when moving up and down in the hole, the timing at which one of the magnetic bullets enters the same magnetic field generated by one of the bullets is slightly different, and outputs in opposite directions are obtained within the same magnetic field; This can be done using
以下、この発明の実施例を、図面を参照しなが
ら詳しく説明する。
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
第１図はこの発明にかかる地盤の深度別沈下量
測定方法の一実施例を説明する図、第２図はこの
発明にかかる地盤の深度別沈下量測定方法に用い
られる磁気検出装置の先端部とマグネツト弾をあ
らわす斜視図、第３図は磁気検出装置の回路図で
ある。この発明にかかる地盤の深度別沈下量測定
方法に基づき測定を行うためには、第１図イにみ
るように、まず、測定地点において、地表から不
動点となる基盤１まで到達するボーリング孔２を
穿ち、さらに塩化ビニール等の絶縁物よりなる保
孔管３をボーリング孔２内に埋設してボーリング
孔２を保孔する。つづいて、第１図ロにみるよう
に、小型油圧ジヤツキを用いたマグネツト弾挿入
装置４を保孔管３内に降下させ、このマグネツト
弾挿入装置４を使つて、弾丸状のマグネツト弾５
を、保孔管３を貫かせて各深度の地盤に打ち込
む。マグネツト弾の挿入が完了すると、測定の準
備が整う。 FIG. 1 is a diagram illustrating an embodiment of the method for measuring the amount of subsidence according to depth of the ground according to the present invention, and FIG. 2 shows the tip of a magnetic detection device used in the method for measuring the amount of subsidence according to the depth of the ground according to the present invention. FIG. 3 is a perspective view showing a magnetic bullet, and FIG. 3 is a circuit diagram of a magnetic detection device. In order to perform measurements based on the method for measuring the amount of ground subsidence by depth according to the present invention, as shown in Figure 1A, first, at the measurement point, a bore hole 2 that reaches from the ground surface to the base 1, which is a fixed point. A hole storage pipe 3 made of an insulating material such as vinyl chloride is further buried in the borehole 2 to maintain the borehole 2. Next, as shown in FIG.
are driven into the ground at various depths through the hole storage pipe 3. Once the magnetic bullet has been inserted, it is ready for measurement.
測定段階では、第２図および第３図の実施例に
みるような磁気検出装置が使用される。この磁気
検出装置は、２個のブリツジ型磁気抵抗素子８
ａ，８ｂを合成樹脂製円柱７内に埋設してなる磁
界測定用プローブ６と、バランス回路（差動増幅
器ともいう１３およびその出力を検出する検流計
１４を備える測定器１２と、プローブ６内の出力
をバランス回路１３に伝える導線１０が内蔵され
たケーブル９とを備えている。磁界測定用プロー
ブ６は、第３図にみられるように、合成樹脂円柱
７内に２個のブリツジ型磁気抵抗素子８ａ，８ｂ
を、中心部の上下位置で数cmの間隔を置きながら
互いに極性が逆方向になるように（それぞれの出
力端子で逆方向の出力が得られるように）配置さ
せている。ブリツジ型磁気抵抗素子は、四つの抵
抗素子R1〜R4がブリツジ状につながれて形成さ
れているもので、この発明においては、第４図の
等価回路にみるように、電源電池に接続されてい
る入力端子Ａと、その対向位置にあるアース端子
Ｃと、両端子Ａ，Ｃ直列に配置された抵抗素子
R1，R2の中間点およびR3，R4の中間点に位置す
る出力端子Ｂ，Ｄを備えている。各ブリヅジ型磁
気抵抗素子８ａ，８ｂは磁界の中に入るとその出
力端子Ｂ，Ｄから磁界の極性および強さに対応し
た出力を発するが、極性が逆方向になつているた
め、それぞれの出力は逆方向となる。測定器１２
内にあるバランス回路１３は、第３図にみるよう
に、プローブ６内の磁気抵抗素子８ａ，８ｂの共
通出力端子Ｂ，Ｂ，Ｄ，Ｄと接続されており、両
磁気抵抗素子８ａ，８ｂからの出力の和を増幅し
て検流計１４へと伝える。バランス回路１３は、
オフセツト用の可変抵抗器１６を通して接地され
ている。バランス回路１３の出力端子と検流計１
４との間には感度切換スイツチ１７が設けらてい
る。電源電池１５は、バランス回路１３を駆動す
るための電源でもある。 In the measurement phase, a magnetic detection device as seen in the embodiments of FIGS. 2 and 3 is used. This magnetic detection device consists of two bridge type magnetoresistive elements 8
a, 8b embedded in a synthetic resin cylinder 7, a measuring instrument 12 comprising a balance circuit (also called a differential amplifier 13 and a galvanometer 14 for detecting its output), and the probe 6. The cable 9 has a built-in conducting wire 10 that transmits the output from the inside to the balance circuit 13.The magnetic field measurement probe 6 is comprised of two bridge-shaped wires inside a synthetic resin cylinder 7, as shown in FIG. Magnetoresistive elements 8a, 8b
are arranged above and below the center, with an interval of several centimeters, so that their polarities are in opposite directions (so that outputs in opposite directions can be obtained from their output terminals). A bridge type magnetoresistive element is formed by connecting four resistance elements R 1 to R 4 in a bridge shape, and in this invention, as shown in the equivalent circuit of Fig. 4, the bridge type magnetoresistive element is connected to a power supply battery. Input terminal A, located opposite to it, and ground terminal C, and a resistive element placed in series with both terminals A and C.
It has output terminals B and D located at the midpoint between R 1 and R 2 and between R 3 and R 4 . When each bridge type magnetoresistive element 8a, 8b enters a magnetic field, it emits an output corresponding to the polarity and strength of the magnetic field from its output terminals B, D, but since the polarity is in the opposite direction, each output is in the opposite direction. Measuring device 12
As shown in FIG. 3, the balance circuit 13 located inside the probe 6 is connected to common output terminals B, B, D, and D of the magnetoresistive elements 8a and 8b inside the probe 6, and both magnetoresistive elements 8a and 8b are connected to each other. The sum of the outputs from the galvanometer 14 is amplified and transmitted to the galvanometer 14. The balance circuit 13 is
It is grounded through a variable resistor 16 for offset. Output terminal of balance circuit 13 and galvanometer 1
4, a sensitivity changeover switch 17 is provided. The power battery 15 is also a power source for driving the balance circuit 13.
一端がプローブ６に連結され、他端が測定器１
２に連結されているケーブル９内蔵の導線１０に
は、第２図にみられるように、プローブ６内の２
個の磁気抵抗素子８ａ，８ｂの中間点Ｏからの距
離を示す目盛11が付されている。 One end is connected to the probe 6, and the other end is connected to the measuring instrument 1.
As shown in FIG.
A scale 11 indicating the distance from the midpoint O between the magnetoresistive elements 8a and 8b is provided.
地盤の沈下量を測定する際には、第１図ハにみ
るように、プローブ６をボーリング孔２内に降下
させ、マグネツト弾５……の各位置を測定器１２
によつて探知させる。そして、例えば保孔管３の
上端もしくは不動点となる基盤１を基準レベルと
して、その時のマグネツト弾５……の各深度をケ
ーブル９上の目盛１１で読み取る。各マグネツト
弾５は、第１図ニに破線で示すように、地盤の収
縮沈下につれて深度が変化する。そこで、時期を
隔てて各マグネツト弾５……の深度を測定し、そ
れぞれの初期計測値との変位量を地層の収縮量す
なわち沈下量として観測するのである。 When measuring the amount of ground subsidence, as shown in FIG.
be detected by. Then, for example, the upper end of the hole storage pipe 3 or the base 1 serving as a fixed point is set as a reference level, and the respective depths of the magnetic bullets 5 . . . at that time are read on the scale 11 on the cable 9. The depth of each magnetic bullet 5 changes as the ground shrinks and sinks, as shown by the broken line in FIG. 1D. Therefore, the depth of each magnetic bullet 5 is measured at different times, and the amount of displacement from each initial measurement value is observed as the amount of contraction of the strata, that is, the amount of subsidence.
つぎに、磁気検出装置によるマグネツト弾の探
知システムについて、第３図に基づいて説明す
る。プローブ６がボーリング孔２内を降下し、地
盤に挿入されたマグネツト弾５の磁界を通過する
とき、まずプローブ内の下側の磁気抵抗素子８ｂ
が磁界に入り、端子Ｂ，Ｄより出力を始める。そ
の出力は次第に強くなり、磁界の中心（マグネツ
ト弾５に最近接近した位置）でもつとも強く、そ
こから離れるに従い弱くなる。つぎに、これより
少し遅れて、上側の磁気抵抗素子８ａが磁界に入
るため、これの出力端子Ｂ，Ｄからも同様の傾向
の出力が得られる。しかし、それぞれの方向（極
性）が逆であるため、両者の共通端子からは両者
の出力の互いに相殺されたものが和となつて出力
され、バランス回路１３を径て検流計１４により
読みとられる。したがつて、検流計１４にみるバ
ランス回路１３とからの出力とマグネツト弾から
の垂直距離との関係は、第５図に一例としてみる
ような実線の軌跡を描く。図中、両側の破線は各
素子８ａ，８ｂからの個々の出力を示す軌跡であ
る。２個の磁気抵抗素子８ａ，８ｂの中間点Ｏが
マグネツト弾５に最接近したとき、両素子８ａ，
８ｂからの出力が１：１で相殺され、検流計の指
針が零を示す。したがつて、この時のケーブルの
目盛１１を読み取れば、マグネツト弾の正確な深
度が求められるのである。なお、バランス回路内
の可変抵抗器１６は、測定開始時、検流計１４の
針の零位置を調整する働きをする。 Next, a magnetic bullet detection system using a magnetic detection device will be explained based on FIG. When the probe 6 descends into the borehole 2 and passes through the magnetic field of the magnetic bullet 5 inserted into the ground, the lower magnetoresistive element 8b inside the probe first
enters the magnetic field, and output begins from terminals B and D. The output gradually becomes stronger, being stronger at the center of the magnetic field (the position closest to the magnet bullet 5) and weakening as it moves away from there. Next, a little later than this, the upper magnetoresistive element 8a enters the magnetic field, so outputs with a similar tendency are obtained from its output terminals B and D. However, since their respective directions (polarity) are opposite, the mutually canceled outputs of both are outputted as a sum from their common terminal, and the output is passed through the balance circuit 13 and read by the galvanometer 14. It will be done. Therefore, the relationship between the output from the balance circuit 13 seen by the galvanometer 14 and the vertical distance from the magnetic bullet draws a solid line locus as shown in FIG. 5 as an example. In the figure, the broken lines on both sides are loci showing the individual outputs from each element 8a, 8b. When the intermediate point O between the two magnetoresistive elements 8a, 8b approaches the magnetic bullet 5, both elements 8a,
The outputs from 8b are canceled out in a 1:1 ratio, and the galvanometer pointer shows zero. Therefore, by reading the scale 11 on the cable at this time, the accurate depth of the magnetic bullet can be determined. Note that the variable resistor 16 in the balance circuit functions to adjust the zero position of the needle of the galvanometer 14 at the start of measurement.
マグネツト弾の挿入に際し、実施例において
は、小型油圧ジヤツキを利用したマグネツト弾挿
入装置を使用していたが、これに限られるもので
はなく、タツカーや爆薬を用いてマグネツト弾を
打ち込むようにしても良く、その挿入方法に制限
はない。マグネツト弾の形状、構造も図示のもの
に限定されない。 When inserting a magnetic bullet, in the embodiment, a magnetic bullet insertion device using a small hydraulic jack is used, but the invention is not limited to this, and it is also possible to insert a magnetic bullet using a tackifier or explosives. Well, there are no restrictions on how to insert it. The shape and structure of the magnetic bullet are not limited to those shown in the drawings.
磁気測定用プローブには、実施例においては、
ブリツジ型磁気抵抗素子が使用されていたが、こ
れに限られるものではなく、ホール素子等他の感
磁性素子を用いても構わない。検出装置の電気回
路構成も実施例のものに限定されることはなく、
様々のものが採用される。 In an embodiment, the magnetic measurement probe includes:
Although a bridge type magnetoresistive element has been used, the present invention is not limited to this, and other magnetically sensitive elements such as a Hall element may also be used. The electric circuit configuration of the detection device is not limited to that of the example,
Various things are adopted.
深度の計測に際して、前記実施例では、ケーブ
ルに付した目盛を用いたが、他の手段によつても
よいことは言うまでもない。 Although the scale attached to the cable was used in the above embodiment to measure the depth, it goes without saying that other means may be used.
以上に詳しくみたように、請求項１、２記載の
発明にかかる方法は、下記のような優れた効果を
奏することができる。
As described above in detail, the method according to the invention according to claims 1 and 2 can produce the following excellent effects.
効果 地盤の深度別沈下量が極めて簡単かつ容
易に測れる。これは、準備作業や測定作業が簡
単かつ容易であることに起因している。Effect: The amount of subsidence at different depths of the ground can be measured very simply and easily. This is because the preparation work and measurement work are simple and easy.
準備作業は、磁気検出装置とは全く別体の各
マグネツト弾をボーリング孔側壁面の各測定位
置に一度だけ打ち込むだけで済み、測定作業
は、マグネツト弾とは別体の磁気測定用プロー
ブを上げ下げして磁気検出する程度のことを一
定時間ごとに行うだけ済む。 Preparation work only requires firing each magnetic bullet, which is completely separate from the magnetic detection device, into each measurement position on the side wall of the borehole once, and the measurement work involves raising and lowering the magnetic measurement probe, which is separate from the magnetic bullet. All you need to do is to detect the magnetic field at regular intervals.
効果 測定結果の信頼性が高い。これは、測定
系に外部環境変動に伴う誤差が殆どないからで
ある。Effect: High reliability of measurement results. This is because the measurement system has almost no errors due to changes in the external environment.
間歇的に行なう測定作業そのものは短時間で
あるが、その間に長いブランク期間があつてボ
ーリング孔周りでは様々な外部環境変動が起こ
る。しかし、ブランク期間中、この発明では、
プローブはボーリング孔から引き上げ、別体の
各マグネツト弾を残しておくだけである。した
がつて、放置状態にあるマグネツト弾には打ち
込み位置の沈下に応じた測定上必要な移動が生
じるが、ボーリング孔内にプローブを放置しな
い測定系が外部環境変動による影響を受け難
い。 Although the measurement work itself is performed intermittently for a short time, there is a long blank period in between, and various external environmental changes occur around the borehole. However, during the blank period, this invention
Simply pull the probe out of the borehole, leaving each magnetic projectile in its separate pieces. Therefore, although the magnetic projectile left in the standing state undergoes movement necessary for measurement in accordance with the sinking of the implantation position, a measurement system in which the probe is not left in the borehole is less susceptible to external environmental changes.
効果 測定点を増やす（多くする）ことが容易
である。これは、単に打ち込むマグネツト弾の
数のみ増やすだけであるからである。Effects It is easy to increase (increase) the number of measurement points. This is because only the number of magnetic bullets to be fired is increased.
請求項２記載の発明の方法は、加えて、磁気
検出装置の構成が簡単であるとともに零位法に
よることが容易に実現され、しかも、零位近傍
での精度がよいため、非常に精密な測定結果が
もたらされるという利点がある。 In addition, the method of the invention described in claim 2 has a simple configuration of the magnetic detection device, can easily implement the zero position method, and has good accuracy near the zero position, so it can be used for very precise detection. This has the advantage of providing measurement results.
第１図はこの発明にかかる地盤の深度別沈下量
測定方法の一実施例を説明する説明図、第２図は
この発明の実施に用いられる磁気検出装置のプロ
ーブ部分とマグネツト弾をあらわす斜視図、第３
図は磁気検出装置の回路図、第４図は磁気検出装
置を構成するブリツジ型磁気抵抗素子の等価回路
図、第５図は磁気検出検出装置を構成する検流計
が表示する値の軌跡をあらわす図である。
１……基盤、２……ボーリング孔、５……マグ
ネツト弾、６……磁気測定用プローブ、８ａ，８
ｂ……ブリツジ型磁気抵抗素子、９……ケーブ
ル、１０……導線、１２……測定器、１３……バ
ランス回路、１４……検流計。
FIG. 1 is an explanatory diagram illustrating an embodiment of the method for measuring ground subsidence by depth according to the present invention, and FIG. 2 is a perspective view showing a probe portion and a magnetic bullet of a magnetic detection device used in carrying out the present invention. , 3rd
The figure shows the circuit diagram of the magnetic detection device, Figure 4 shows the equivalent circuit diagram of the bridge-type magnetoresistive element that makes up the magnetic detection device, and Figure 5 shows the trajectory of the values displayed by the galvanometer that makes up the magnetic detection device. This is a diagram showing this. 1... Base, 2... Borehole, 5... Magnetic bullet, 6... Magnetic measurement probe, 8a, 8
b... Bridge type magnetic resistance element, 9... Cable, 10... Conductor, 12... Measuring device, 13... Balance circuit, 14... Galvanometer.
Claims (1)
グ孔における側壁面の深度の異なる位置ごとに
個々にマグネツト弾を打ち込んでおいて、各マグ
ネツト弾が作る磁界を、前記ボーリング孔内に降
下させた取出し自在の時期測定用プローブを含む
磁気検出装置により検出されて前記各マグネツト
弾の基準レベルからの位置を測定する操作を時間
を隔てて行い前記各マグネツト弾の位置変動量を
調べることにより、地盤中の前記各深度における
沈下量を測定するようにすることを特徴とする地
盤の深度別沈下量測定方法。 ２ 磁気検出装置として、ブリツジ型磁気抵抗素
子２個を有してボーリング孔内に降ろされる磁界
測定用プローブと、バランス回路およびその出力
を検出する検流計を有する測定器と、前記ブリツ
ジ型磁気検出抵抗素子２個の出力をバランス回路
に伝える導線が内蔵されたケーブルとをそれぞれ
備え、前記ブリツシ型磁気抵抗素子２個は、それ
ぞれの出力端子を共通とし、かつ磁界測定用プロ
ーブがボーリング孔内を昇降するとき前記各マグ
ネツト弾のうちのひとつが作る同じ磁界に入る時
期が少しばかりずれ、しかも同一磁界内において
逆方向の出力が得られるようにプローブ内に配置
されている磁気検出装置を用いる特許請求の範囲
第１項記載の地盤の深度別沈下量測定方法。[Scope of Claims] 1 Magnetic bullets are individually driven into different positions of the side wall surface in a borehole drilled in the ground where the amount of subsidence is to be measured, and the magnetic field generated by each magnetic bullet is applied to the borehole. The amount of positional variation of each magnetic bullet is detected by a magnetic detection device including a removable timing measuring probe lowered into the hole and measures the position of each magnetic bullet from a reference level at intervals of time. A method for measuring the amount of subsidence by depth of the ground, characterized in that the amount of subsidence at each of the depths in the ground is measured by examining: 2. As a magnetic detection device, a magnetic field measuring probe having two bridge-type magnetoresistive elements and lowered into the borehole, a measuring instrument having a balance circuit and a galvanometer for detecting its output, and the bridge-type magnetic Each of the two detection resistance elements has a built-in cable with a conductor wire that transmits the outputs of the two detection resistance elements to a balance circuit, and the two bullet type magnetoresistive elements have a common output terminal, and the magnetic field measurement probe is connected to the borehole. When the probe is moved up and down, the timing of entering the same magnetic field created by one of the magnetic bullets is slightly different, and a magnetic detection device is placed inside the probe so that outputs in opposite directions can be obtained within the same magnetic field. A method for measuring the amount of subsidence by depth of the ground according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7023483A JPS59195122A (en) | 1983-04-20 | 1983-04-20 | Measuring method of land subsidence according to depth and magnetic detector to be used for measurement |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7023483A JPS59195122A (en) | 1983-04-20 | 1983-04-20 | Measuring method of land subsidence according to depth and magnetic detector to be used for measurement |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59195122A JPS59195122A (en) | 1984-11-06 |
| JPH0551850B2 true JPH0551850B2 (en) | 1993-08-03 |
Family
ID=13425668
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7023483A Granted JPS59195122A (en) | 1983-04-20 | 1983-04-20 | Measuring method of land subsidence according to depth and magnetic detector to be used for measurement |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59195122A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0769195B2 (en) * | 1989-11-10 | 1995-07-26 | 機動建設工業株式会社 | Ground fluctuation measuring device |
| KR20020039276A (en) * | 2002-02-19 | 2002-05-25 | 김윤상 | Settlement Measurement Method for the Compulsory Replacement Method in Soft Clay |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4957610A (en) * | 1972-10-03 | 1974-06-04 | ||
| JPS52142807A (en) * | 1976-05-24 | 1977-11-29 | Keisoku Risaachi Konsarutanto | Multiipurpose investigating and measuring tube and range checking apparatus for subsoil deformation |
| JPS56141514A (en) * | 1980-04-04 | 1981-11-05 | Nec Corp | Length measuring device |
-
1983
- 1983-04-20 JP JP7023483A patent/JPS59195122A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4957610A (en) * | 1972-10-03 | 1974-06-04 | ||
| JPS52142807A (en) * | 1976-05-24 | 1977-11-29 | Keisoku Risaachi Konsarutanto | Multiipurpose investigating and measuring tube and range checking apparatus for subsoil deformation |
| JPS56141514A (en) * | 1980-04-04 | 1981-11-05 | Nec Corp | Length measuring device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59195122A (en) | 1984-11-06 |
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