JPH0523719B2 - - Google Patents
Info
- Publication number
- JPH0523719B2 JPH0523719B2 JP62197929A JP19792987A JPH0523719B2 JP H0523719 B2 JPH0523719 B2 JP H0523719B2 JP 62197929 A JP62197929 A JP 62197929A JP 19792987 A JP19792987 A JP 19792987A JP H0523719 B2 JPH0523719 B2 JP H0523719B2
- Authority
- JP
- Japan
- Prior art keywords
- displacement
- wave
- waves
- ground
- signal
- 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 - Fee Related
Links
- 238000006073 displacement reaction Methods 0.000 claims description 47
- 238000000034 method Methods 0.000 claims description 16
- 230000001186 cumulative effect Effects 0.000 claims description 14
- 238000005259 measurement Methods 0.000 claims description 14
- 239000003365 glass fiber Substances 0.000 claims description 11
- RSWGJHLUYNHPMX-UHFFFAOYSA-N Abietic-Saeure Natural products C12CCC(C(C)C)=CC2=CCC2C1(C)CCCC2(C)C(O)=O RSWGJHLUYNHPMX-UHFFFAOYSA-N 0.000 claims description 10
- KHPCPRHQVVSZAH-HUOMCSJISA-N Rosin Natural products O(C/C=C/c1ccccc1)[C@H]1[C@H](O)[C@@H](O)[C@@H](O)[C@@H](CO)O1 KHPCPRHQVVSZAH-HUOMCSJISA-N 0.000 claims description 10
- KHPCPRHQVVSZAH-UHFFFAOYSA-N trans-cinnamyl beta-D-glucopyranoside Natural products OC1C(O)C(O)C(CO)OC1OCC=CC1=CC=CC=C1 KHPCPRHQVVSZAH-UHFFFAOYSA-N 0.000 claims description 10
- 239000002131 composite material Substances 0.000 claims description 9
- 238000004458 analytical method Methods 0.000 claims description 7
- 238000000691 measurement method Methods 0.000 claims description 4
- 238000012545 processing Methods 0.000 claims description 4
- 239000000025 natural resin Substances 0.000 claims 1
- 239000012791 sliding layer Substances 0.000 description 7
- 238000012360 testing method Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 238000013001 point bending Methods 0.000 description 5
- 239000002689 soil Substances 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 229920005615 natural polymer Polymers 0.000 description 2
- 239000002952 polymeric resin Substances 0.000 description 2
- 230000002265 prevention Effects 0.000 description 2
- 238000003672 processing method Methods 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 238000010008 shearing Methods 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 235000008331 Pinus X rigitaeda Nutrition 0.000 description 1
- 235000011613 Pinus brutia Nutrition 0.000 description 1
- 241000018646 Pinus brutia Species 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000000805 composite resin Substances 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 239000003673 groundwater Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000009940 knitting Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 238000010583 slow cooling Methods 0.000 description 1
- 239000011343 solid material Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Geophysics And Detection Of Objects (AREA)
- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明はアコーステイツクミツシヨン法を用い
る地盤内変位の測定方法および装置に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for measuring displacement in the ground using the acoustic compression method.
一般に、地盤内の変位測定においては伸縮計、
傾斜計、地中ひずみ計等による方法が用いられて
いるが、多大の労力と経費を必要とするわりに地
中の変位挙動を敏感に表示する調査資料は得られ
難い。たとえば、地すべり調査においては抑止工
法の検討に当たつて、地すべりの発生誘因を明ら
かにする上で、地下水位の変化など滑動条件に関
するパラメータと滑動速度の関係を求める必要が
あり、地すべりの挙動を従来よりも高感度で検出
できるような計測方法が求められている。
In general, extensometers are used to measure displacement within the ground.
Methods using inclinometers, underground strain meters, etc. are used, but they require a great deal of effort and expense, and it is difficult to obtain survey materials that sensitively display underground displacement behavior. For example, in landslide investigation, when considering prevention methods, it is necessary to determine the relationship between parameters related to sliding conditions such as changes in groundwater level and sliding speed in order to clarify the triggers of landslide occurrence. There is a need for a measurement method that allows detection with higher sensitivity than conventional methods.
最近、固体材料の変形や破壊に際して微小弾性
波（AE波）が放出される現象をとらえ亀裂の発
生を計測する手段として注目されている応用技術
にAE法と呼ばれる計測方法がある。 Recently, a measurement method called the AE method has been attracting attention as a means of measuring the occurrence of cracks by capturing the phenomenon in which minute elastic waves (AE waves) are emitted when solid materials deform or break.
第５図にかかるAE法による計測システム概要
を示す。すなわち、AEトランジスジユーサTR
によつて検出されたAE信号をプリアンプAMPで
増幅した後、磁気テープMTに収録する一方、バ
ンドパス・フイルターFTにより雑音を除去し、
AE分析装置ANLに入力する。AE分析装置ANL
では、一定の閾値をこえた信号波形についてリン
グダウン方式のデジタルパルスに変換し、かつ一
定の不換時間を経て受信される各群のAE信号を
１イベントとして１つのデジタルパルスに変換
し、それによつて単位時間当たりの各々の計数値
をAEカウント・レイトおよびAEイベント・レイ
トとして夫々出力し、かつそれらの累積値につい
ても実時間で出力する。 Figure 5 shows an overview of the measurement system using the AE method. That is, AE Transis Yusa TR
After amplifying the AE signal detected by the preamplifier AMP, it is recorded on a magnetic tape MT, while noise is removed using a bandpass filter FT.
Input to AE analyzer ANL. AE analyzer ANL
Then, the signal waveform exceeding a certain threshold is converted into a ring-down digital pulse, and each group of AE signals received after a certain inconversion time is converted into one digital pulse as one event. Therefore, each count value per unit time is output as an AE count rate and an AE event rate, and their cumulative value is also output in real time.
この方法を用いて地盤内の土の挙動を音によつ
て敏感にとらえる方法が検討されており、従来に
おいても地表から打設した金属棒をウエーブガイ
ドとして土塊内部に発生したとみられるAEを検
出したことが報告されている。しかし、一般にレ
オロジー的な変形性を有する含水した粒状媒質か
らはAE波の発生は少なくかつAE波の伝播減衰も
大きい事などを考慮すると、土塊から直接的に
AE波を検出するウエーブガイド方式では、地す
べり計測におけるAEの発生頻度と地すべり挙動
の間に対応関係を見い出すことが困難であると考
えられる。 Using this method, a method to sensitively detect the behavior of soil in the ground using sound has been studied, and in the past, metal rods driven from the ground surface were used as wave guides to detect AE that appears to have occurred inside the soil mass. It has been reported that. However, considering that AE waves are generally generated less from water-containing granular media with rheological deformability and the propagation attenuation of AE waves is large,
With the waveguide method that detects AE waves, it is considered difficult to find a relationship between the frequency of AE occurrence and landslide behavior in landslide measurements.
本発明者等は、前記の問題点を解決するため
の、土塊から発生するAE波それ自体ではなく地
中に埋設したAE波発生体が土塊の変位によつて
変形する際に発生するAE波を検出することによ
つて、地盤内における土塊のの変位挙動を間接的
にとらえることに着目し、AE法の技術の地盤内
変位の計測、地すべり計測への応用に実用化の方
途を見出した。 In order to solve the above-mentioned problems, the present inventors have proposed an AE wave generated when an AE wave generating body buried underground is deformed by the displacement of the earth clod, rather than the AE wave itself generated from the earth clod. By detecting this, we focused on indirectly capturing the displacement behavior of soil clods within the ground, and found a way to put the AE method into practical use in measuring displacement within the ground and measuring landslides. .
すなわち前記従来技術の問題点は、地盤内に埋
設した計測棒により変形する対応する微小端正波
（アコーステイツクエミツシヨン：以下AE波と略
称する）を発生させ、前記AE波を前記計測棒の
上下部に夫々設けた一対のトランスジユーサによ
つて感知してAE波に対応する電気的なAE信号波
に変換し、前記AE信号波の解析に基いて前記一
対のトランスジユーサからの信号到達時間差によ
る地盤中の変位の発生位置、変位の発生位置の分
布による変位の発生範囲、ならびにAE信号波の
生起率（イベント・レイト）により変位速度およ
び累積生起数（累積イベント数）により変位量を
求めることを特徴とするアコーステイツクミツシ
ヨン法により地盤内変位の測定方法によつて解決
される。
In other words, the problem with the prior art is that a measuring rod buried in the ground generates a corresponding minute positive wave (acoustic emission: hereinafter abbreviated as AE wave) that is deformed, and the AE wave is transmitted to the measuring rod. A pair of transducers installed at the top and bottom respectively detect the AE wave and convert it into an electrical AE signal wave corresponding to the AE wave, and based on the analysis of the AE signal wave, a signal from the pair of transducers is detected. The location of displacement in the ground due to the arrival time difference, the range of occurrence of displacement based on the distribution of the location of displacement, and the amount of displacement based on the displacement speed and cumulative number of occurrences (cumulative number of events) based on the rate of occurrence of AE signal waves (event rate). This problem can be solved by measuring the displacement in the ground using the acoustic measurement method, which is characterized by finding the following.
さらに本発明者は前記AE法による地盤内変位
を測定する際に計測棒から得られるAE波を解析
して地すべりの発生と密接に関連するパラメータ
としての地盤内の流動層の位置（深さ）、範囲
（厚さ）ならびに流動速度および流動量等を迅速
に求め、実際の地すべり対策に有効な測定装置の
開発を試みた。 Furthermore, the present inventor analyzed the AE waves obtained from the measurement rod when measuring the displacement in the ground using the AE method, and determined the position (depth) of the fluidized layer in the ground as a parameter closely related to the occurrence of landslides. , range (thickness), flow velocity, flow volume, etc., and attempted to develop a measuring device that is effective for actual landslide countermeasures.
前記測定装置は、グラスフアイバおよび高分子
天然樹脂（レンジ）の複合体からなり変位に比例
しかつ伝播減衰の少ないAE波を一定に発生する
計測棒と、前記計測棒の上下端に設けられ該計測
棒から発生されるAE波を感知してこれに対応す
る電気的なAE信号波を発生する一対のトランス
ジユーサならびに前記トランスジユーサから出力
されるAE信号波を解析して地盤中の変位の発生
位置、発生範囲、変位速度および変位量を求める
処理システムを備えていることを特徴とする地盤
内変位の測定装置によつて与えられる。 The measuring device includes a measuring rod that is made of a composite of glass fiber and a natural polymer resin (range) and that constantly generates an AE wave that is proportional to displacement and has little propagation attenuation, and a measuring rod that is installed at the upper and lower ends of the measuring rod to A pair of transducers detect the AE waves generated from the measuring rod and generate corresponding electrical AE signal waves, and the AE signal waves output from the transducers are analyzed to determine the displacement in the ground. This is provided by an in-ground displacement measuring device characterized by being equipped with a processing system for determining the occurrence position, occurrence range, displacement speed, and displacement amount.
（作用）
本発明によれば地盤内の変位によつて地中に埋
設された計測棒が変形する際にこの変形に応じて
前記AE波が発生され、一対のトランスジユーサ
によつて電気的なAE信号波に変換されて処理シ
ステムに出力される。これらのAE信号波の中、
所定の関値を越えるものがリングダウン方式のデ
ジタルパルスに変形され、前記一対のトランスジ
ユーサへのAE信号波を到達時間差に基いて地盤
内の変位の位置さらにはその範囲が与えらえる。
一方一定の不感時間を経て受信されるAE波形毎
に１イベントとしての一つのデジタルパルスが出
力され、単位時間当りのかゝるパルスの計数値に
よるAEイベント・レイトに基く変位速度ならび
にその累積値としてのAEイベントの累積数に基
く変位量が夫々与えられる。かゝる波形解析の結
果はたとえばパーソナルコンピユータのメモリに
記憶され、具体的なデータの計算、表示、記録お
よび警報の発生等に用いられる。(Function) According to the present invention, when a measurement rod buried underground is deformed due to displacement in the ground, the AE wave is generated in response to this deformation, and the pair of transducers generates an electrical wave. The signal is converted into an AE signal wave and output to the processing system. Among these AE signal waves,
Those exceeding a predetermined value are transformed into ring-down digital pulses, and the position and range of displacement within the ground is given based on the difference in arrival time of the AE signal waves to the pair of transducers.
On the other hand, one digital pulse as one event is output for each AE waveform received after a certain dead time, and the displacement velocity based on the AE event rate and its cumulative value are calculated by the count value of such pulses per unit time. The displacement amount based on the cumulative number of AE events is given respectively. The results of such waveform analysis are stored in the memory of a personal computer, for example, and used for calculating, displaying, recording, and issuing alarms.
（計測棒）
本発明においては地盤内変位を間接的に検知す
る手段としての計測棒がその重要な構成要素をな
す。このような計測棒の材料に求められる特性と
しては、材料の変位に比例して高感度でAE波を
発生すること、発生AE波が伝播減衰の少ない周
波数成分からなることおよび変形の初期から一定
して継続的にAE波を発生すること等であるが、
実用上かゝる要件を充分に満足する材料は従来全
く知られていなかつた。(Measuring rod) In the present invention, a measuring rod is an important component as a means for indirectly detecting displacement in the ground. The characteristics required of the material for such a measuring rod are that it should generate AE waves with high sensitivity in proportion to the displacement of the material, that the generated AE waves should consist of frequency components with little propagation attenuation, and that they should be constant from the beginning of deformation. and continuously generate AE waves, etc.
No material has hitherto been known that fully satisfies these requirements in practical terms.
本発明者等は種々の材料についてそれらの材質
および加工方法等に関して実験、研究を重ねた結
果、天然高分子樹脂の一種としてのロジン（松
脂）とグラスフアイバとの組合せによる複合体が
本発明の目的のために最適であることを見出し
た。 As a result of repeated experiments and research regarding the quality and processing methods of various materials, the present inventors have discovered that the present invention is a composite material made of a combination of rosin (pine resin), which is a type of natural polymer resin, and glass fiber. found to be optimal for the purpose.
すなわちたとえば溶融したロジンをグラスフア
イバで編成したケージを包埋するようにロツド状
に流し込み、常温まで徐冷固化して得られるロジ
ン−松脂の複合体が前記諸条件を充分に満足する
AE発生媒体となり得ることを発見した。 That is, for example, a rosin-pine resin composite obtained by pouring molten rosin into a rod shape so as to embed it in a cage made of glass fibers and slowly cooling it to room temperature to solidify it fully satisfies the above conditions.
We discovered that it can be a medium for AE generation.
このような優れた特性は主としてロジン自体の
性質に基くものであると共に、変形の際にロジン
中に発生する亀裂の進展がガラスフアイバによつ
て遮断され、変形の初期から終期までの全過程を
通して微妙な弾性波（AE波）が常に継続して均
一に発生されることによるものであると推定され
る。 These excellent properties are mainly due to the properties of the rosin itself, and the growth of cracks that occur in the rosin during deformation is blocked by the glass fibers, and the growth of cracks that occur in the rosin during deformation is blocked by the glass fibers, and they are maintained throughout the entire process from the beginning to the end of deformation. It is presumed that this is due to the constant and uniform generation of subtle elastic waves (AE waves).
かゝるリジン−グラスフアイバ複合体のAE特
性を実験的に求めるために第１図にその概要を示
す三点曲げ試験を行なつた。 In order to experimentally determine the AE characteristics of such a lysine-glass fiber composite, a three-point bending test, the outline of which is shown in Figure 1, was conducted.
インストロンテスタ１によつてロジン−グラス
フアイバ複合体２に、100mmスパンで剪断応力を
加え、トランスジユーサ３から出力されるその
AE信号波をプリアンプ４により増幅し、信号処
理装置５によつて解析して横軸のたわみ変形量に
対する縦軸のAEイベントレートおよび累積AEイ
ベント数との関係をPENレコーダ６もしくはＸ
−Ｙレコーダ７による表示によつて求めた（その
他図中８はオシログラフ、９はダイアルゲージで
ある）。 The Instron tester 1 applies shear stress to the rosin-glass fiber composite 2 over a span of 100 mm, and the shear stress is output from the transducer 3.
The AE signal wave is amplified by a preamplifier 4, analyzed by a signal processing device 5, and the relationship between the deflection deformation amount on the horizontal axis and the AE event rate and cumulative number of AE events on the vertical axis is measured using a PEN recorder 6 or X.
- Determined by the display on the Y recorder 7 (in addition, 8 in the figure is an oscillograph and 9 is a dial gauge).
この結果複合体の加工方法等にもよるが、少な
くとも1.4mmのたわみ量まで、そして多くの場合
ではさらに10mmのたわみ量まで、たわみ変形量と
累積イベント数とが比例関係にあることが判明し
た。 As a result, although it depends on the processing method of the composite, it was found that the amount of deflection deformation and the cumulative number of events are proportional to the amount of deflection up to at least 1.4 mm, and in many cases even up to 10 mm. .
このような計測棒はたとえば具体的に第２図に
示すようにモルタル１１で固定された塩ビパイプ
１２およびスチールパイプ１３からなる二重構造
管中にグラスフアイパーロジン複合体１４を固定
して構成され、スチールパイプ１３の上下端部に
はマグネツト１５，１６を介してAEトランスジ
ユーサ１７，１８が着脱可能に取付けられてい
る。図中１９，２０は信号リード線である。 For example, as shown in FIG. 2, such a measuring rod is constructed by fixing a glass fiber rosin composite 14 in a double-structured pipe consisting of a PVC pipe 12 and a steel pipe 13 fixed with mortar 11. AE transducers 17 and 18 are removably attached to the upper and lower ends of the steel pipe 13 via magnets 15 and 16. In the figure, 19 and 20 are signal lead wires.
このような計測棒を用いた地盤内変位の測定装
置による地盤中のAE発生位置（変位発生位置）、
範囲、変位量および変位速度を求める波形解析の
具体的な方法を以下説明する。
The AE occurrence position in the ground (displacement occurrence position) using a measuring device for measuring displacement in the ground using such a measuring rod,
A specific method of waveform analysis for determining the range, displacement amount, and displacement speed will be described below.
変位発生位置の推定
地盤内で発生する変位挙動は、地中のAE計測
棒の変形の伴い、その過程で発生するAE波は、
計測棒の両端に固定された一対のトランスデユー
サーによつて検出されるが、この時、AE波の発
生位置に応じてAE信号波の到達時間に差が生じ
る。この時間差をデユアル・デジタル・オシロス
コープ等によつて求めれば、次式によつてAE波
の発生位置を計測棒上に標定することができる。
即ち、第２図中、AE波の発生位置は、
Ｌ＝（L0＋Vp・ΔT）／２ ……＜１＞
Vp：AE計測棒のＰ波伝播速度
△Ｔ：AE波の到達時間差
L0：トランスジユーサ曲の距離
また、AE波の発生位置の分布から、地盤内で
変位を生じた範囲（幅）を次式で表わされる：
ｔ＝Lmax−Lmin ……＜２＞
ただしLmax＝（L0＋Vp・△Tmax）／２
Lmin＝（L0＋Vp・△Tmin）／２
△Tmaxと△Tminはそれぞれ到達時間差の最
大値と最小値である
これを地すべり計測の場合に適用すると、AE
波の発生装置における頻度分布との範囲は、それ
ぞれ滑動層の挙動と層厚（幅）を指示する。Estimating the position of displacement The displacement behavior that occurs in the ground is accompanied by the deformation of the AE measurement rod underground, and the AE waves generated in the process are
It is detected by a pair of transducers fixed at both ends of the measuring rod, but at this time, there is a difference in the arrival time of the AE signal wave depending on the position where the AE wave is generated. If this time difference is determined using a dual digital oscilloscope or the like, the generation position of the AE wave can be located on the measuring rod using the following equation.
That is, in Fig. 2, the generation position of the AE wave is L = (L 0 +Vp・ΔT)/2 ...<1> Vp: P wave propagation velocity of the AE measuring rod △T: Arrival time difference of the AE wave L 0 : Distance of transducer curve Also, from the distribution of the AE wave generation position, the range (width) where displacement occurs in the ground can be expressed by the following formula: t = Lmax - Lmin ...<2> However, Lmax = ( L 0 +Vp・△Tmax)/2 Lmin=(L 0 +Vp・△Tmin)/2 △Tmax and △Tmin are the maximum and minimum values of the arrival time difference, respectively. If this is applied to landslide measurement, the AE
The range of the frequency distribution in the wave generator dictates the behavior and layer thickness (width) of the sliding layer, respectively.
次に、地層間のずれによつて起こるAE計測棒
の変形を第３図に示すように両端固定の梁に剪段
力が作用したとこの問題として考える（地すべり
計測の場合）と、滑動量Ｓおよび滑動速度ｕは次
式であらわすことができる。 Next, if we consider the deformation of the AE measuring rod caused by the displacement between the strata as shown in Figure 3, when a shearing force is applied to a beam fixed at both ends (in the case of landslide measurement), we can calculate the amount of sliding. S and sliding speed u can be expressed by the following equation.
Ｓ＝Ｌ／（2t）・△（AE）・ΣN（AE）
……＜３＞
ｕ＝Ｌ／（2t）・△（AE）・Ｒ（AE）
……＜４＞
ただし、
△（AE）：３点曲げ試験における１イベント当り
のたわみ量
ΣN（AE）：AEの累積イベント数
Ｒ（AE）：AEイベント・レイト
Ｌ：３て曲げ試験におけるスパン
ｔ：滑動層の厚さ
なお、上式において、Ｌ／（2t）は３点曲げ試
験の変形係数Δ（AE）を第３図の場合の変形係数
にするための補正係数で、次の考えに基づいて求
めたものである。すなわち、前記実験の結果は、
AEの累積イベント数がたわみだけでなく、応力
分布の面積にも比例することを示している。従つ
て、第３図の場合と３点曲げ試験の変形において
たわみを等しくおいた場合の応力分布の面積比は
AE発生頻度の比になり、この比で△（AE）を補
正した値は第３図の場合の変形係数になる。つま
り、AE計測棒の変形を第３図に示すように両端
固定の梁に剪断力が作用したときの問題として考
えた場合、この応力分布の面積比はＬ／（2t）に
なる。 S=L/(2t)・△(AE)・ΣN(AE)
...<3> u=L/(2t)・△(AE)・R(AE)
...<4> However, △ (AE): Deflection amount per event in 3-point bending test ΣN (AE): Cumulative number of AE events R (AE): AE event rate L: Span in 3-point bending test t: Thickness of the sliding layer In the above equation, L/(2t) is a correction coefficient to change the deformation coefficient Δ(AE) of the three-point bending test to the deformation coefficient in the case of Figure 3. This was determined based on the following. That is, the results of the experiment are as follows:
It is shown that the cumulative number of AE events is proportional not only to the deflection but also to the area of the stress distribution. Therefore, the area ratio of the stress distribution in the case of Figure 3 and when the deflection in the three-point bending test is kept the same is
This is the ratio of the AE occurrence frequency, and the value obtained by correcting △(AE) using this ratio becomes the deformation coefficient in the case of Fig. 3. In other words, when considering the deformation of the AE measurement rod as a problem when shearing force acts on a beam fixed at both ends as shown in Figure 3, the area ratio of this stress distribution is L/(2t).
以上、計測現場においてAEのイベント・レイ
ト、累積イベント数および到達時間差の計測値が
得られれば、＜１＞、＜２＞、＜３＞、＜４＞式から
変位箇所（滑動層の位置）、変位の範囲（滑動層
の厚さ）、変位量（滑動量）および変位速度（滑
動速度）などの地すべりについての計測資料が得
られる。 As described above, if the measured values of the AE event rate, cumulative number of events, and arrival time difference are obtained at the measurement site, the displacement point (position of the sliding layer) can be determined from equations <1>, <2>, <3>, and <4>. , measurement data about landslides such as the range of displacement (thickness of the sliding layer), amount of displacement (amount of sliding), and displacement speed (sliding speed) can be obtained.
実施例
第２図に示す計測棒を用いそのAE波を第４図
に示すシステムで波形解析して実際の計測現場で
地すべりの要因となる種々のパラメータを測定し
た。Example Using the measuring rod shown in Fig. 2, the AE waves were analyzed by the system shown in Fig. 4 to measure various parameters that are factors of landslides at the actual measurement site.
計測対象地に穿孔した径約120mm、深さ約10ｍ
のボーリング孔に前記二重構造管を埋設し、管中
に計測棒を取付けた。この計測棒はグラフアイバ
を編成してつくつたケージの周囲に100℃で溶融
したロジンを流し込み同温度で静置し空気抜きし
た後、室温（20℃）まで80℃／24時間の割り合い
で歪みが生じないように徐冷固化して調製した。 A hole drilled in the measurement target area with a diameter of approximately 120 mm and a depth of approximately 10 m
The double-structured pipe was buried in the borehole, and a measuring rod was installed inside the pipe. This measuring rod is made by pouring rosin melted at 100℃ around a cage made by knitting graph fibers, leaving it at the same temperature to remove air, and then straining at a rate of 80℃/24 hours until it reaches room temperature (20℃). It was prepared by slow cooling and solidification to prevent the formation of
計測棒の上下端にはAEトランスジユーサとし
てチヤージアンプを内蔵した圧電型加速度センサ
（M568：丸文社製 φ35×65mm）を前記計測棒を
収容するステンレスパイプに夫々マグネツトで離
脱可能に取付け、両センサからの出力を第４図示
のシステムに夫々ケーブルで接続した（下端側の
センサケーブルは使用後のセンサ回収にも用い
る）。 At the upper and lower ends of the measuring rod, piezoelectric acceleration sensors (M568: φ35 x 65 mm, manufactured by Marubunsha) with built-in charge amplifiers as AE transducers are removably attached to the stainless steel pipe that houses the measuring rods using magnets, and both sensors The outputs from each were connected to the system shown in Figure 4 by cables (the sensor cable at the lower end is also used for collecting the sensor after use).
第４図に示す波形解析システムにおいては前記
トランスジユーサからのAE信号波をプリアンプ
１１で増幅し、基準電位を安定化させるためのア
イソレーシヨンモジユール１２およびノイズ除去
のためのフイルタ１３を介してシグナルコンデデ
イシヨナ１４に入力する。こゝで所定の閾値を越
える波形のみをリングダウン計数方式のパルスに
変換しカウンタで係数してAEカウント数のアナ
ログ量としてプロツタ等に出力する。 In the waveform analysis system shown in FIG. 4, the AE signal wave from the transducer is amplified by a preamplifier 11, and then passed through an isolation module 12 for stabilizing the reference potential and a filter 13 for removing noise. and input it to the signal conditioner 14. Here, only the waveforms exceeding a predetermined threshold are converted into pulses of the ring-down counting method, which are coefficiented by a counter and output to a plotter or the like as an analog value of the AE count number.
一方デイジタルエンベローププロセツサ１５に
送つたパルスについては所定の不感時間の経過毎
に生じる単位パルス列を１イベントに対応する１
パルスとカウンタ１６から出力させる。 On the other hand, regarding the pulses sent to the digital envelope processor 15, a unit pulse train generated every time a predetermined dead time elapses is divided into one pulse train corresponding to one event.
A pulse is output from the counter 16.
尚これらのカウンタ出力はAEカウントおよび
イベントの累積数であるがリセツトクロツク１７
から所定の単位時間間隔で指令パルスを入れるこ
とにより単位時間当りの値としてのカウントレイ
トおよびイベントレートを得ることができ、これ
らは前記式＜３＞および＜４＞によつて夫々滑動
層の滑動量および滑動速度を示すためのデータと
なる。 Note that these counter outputs are the AE count and the cumulative number of events, but the reset clock 17
By inputting command pulses at predetermined unit time intervals, the count rate and event rate can be obtained as values per unit time, and these are calculated by the above equations <3> and <4>, respectively. This data is used to indicate the amount and sliding speed.
さらに前記アナログ信号をアナライザ１８で分
析して到着時間差および伝播速度に基いて流動層
の位置および幅を前記式＜１＞、＜２＞によつて
求めた。 Further, the analog signal was analyzed by the analyzer 18, and the position and width of the fluidized bed were determined based on the arrival time difference and the propagation velocity using the equations <1> and <2>.
これらの計測値から測定対象地において5.5〜
6.5ｍの間にすべり面が存在し、厚さ約2.0ｍの滑
動層について滑動量が約18mm、滑動速度が5.04
mm／日であることが測定された。 From these measured values, 5.5 ~
There is a sliding surface between 6.5 m and the sliding layer is approximately 2.0 m thick, the amount of sliding is approximately 18 mm, and the sliding speed is 5.04
mm/day.
以上のように本発明によれば、AE波の計測棒
の上下方に設けた一対のAEトランスジユーサか
らの信号波形を解析してAEイベントの累積値、
イベントレイトおよび到着時間差等を求めること
により地すべり挙動に関するパラメータである滑
動層の位置、厚さ、滑動量および滑動速度を短時
間で正確に決定することができ、それによつて地
すべり抑止工事の効果を有効に判定することがで
きる。
As described above, according to the present invention, the cumulative value of AE events is calculated by analyzing the signal waveform from the pair of AE transducers installed above and below the AE wave measuring rod.
By determining the event rate, arrival time difference, etc., it is possible to accurately determine the position, thickness, amount of sliding layer, and sliding speed of the sliding layer, which are parameters related to landslide behavior, in a short time, thereby improving the effectiveness of landslide prevention works. It can be determined effectively.
第１図は本発明に用いるAE計測棒の特性試験
システムの概要を示す図、第２図は前記計測棒の
説明図、第３図は前記計測棒の変形特性を示す
図。第４図は本発明装置に用いるシステムのブロ
ツク図、第５図はAE波測定の一般原理を示す図
である。
２，１４……AE計測棒（グラスフアイバーロ
ジン複合体）、３，１７，１８……AEトランスジ
ユーサ、１２……塩ビ管、１３……ステインレス
スチール管、１５，１６……マグネツト、１１〜
１８……AE波形解析回路。
FIG. 1 is a diagram showing an outline of a characteristic testing system for an AE measuring rod used in the present invention, FIG. 2 is an explanatory diagram of the measuring rod, and FIG. 3 is a diagram showing deformation characteristics of the measuring rod. FIG. 4 is a block diagram of a system used in the apparatus of the present invention, and FIG. 5 is a diagram showing the general principle of AE wave measurement. 2, 14... AE measuring rod (glass fiber rosin composite), 3, 17, 18... AE transducer, 12... PVC pipe, 13... Stainless steel pipe, 15, 16... Magnet, 11 ~
18...AE waveform analysis circuit.
Claims (1)
る微小弾性波（アコーステイツクエミツシヨン：
以下AE波と略称する）を発生させ、前記AE波を
前記計測棒の上下端部に夫々設けた一対のトラン
ジスジユーサによつて感知してAE波に対応する
電気的なAE信号波に変換し、前記AE信号波の解
析に基いて前記一対のトランジユーサへの信号到
達時間差による地盤中の変位の発生位置、変位の
発生位置の分布による変位の発生範囲、ならびに
AE信号波の生起率（イベントレート）による変
位速度および累積生起数（累積イベント数）によ
る変位量等を求めることを特徴とするアコーステ
イツクミツシヨン法により地盤内変位の測定方
法。 ２ グラスフアイバおよび高分子天然樹脂（ロジ
ン）の複合体からなり変位に比例しかつ伝播減衰
の少ないAE波を発生する計測棒と、前記計測棒
の上下端に設けられ該計測棒から発生されるAE
波を感知してこれに対応する電気的なAE信号波
を発生する一対のトランスジユーサならびに前記
トランスジユーサから出力されるAE信号波を解
析して地盤中の変位の発生位置、発生範囲、変位
速度および変位量を与える処理システムとを備え
ていることを特徴とする地盤内変位の測定装置。 ３ 前記計測棒がグラスフアイバとこれを包埋し
て溶融状態で流し込まれ徐冷固化されたロジンと
の複合体からなる前記特許請求の範囲第２項記載
の測定装置。[Claims] 1. Acoustic waves that correspond to deformation using measurement rods buried in the ground.
(hereinafter abbreviated as AE wave), the AE wave is sensed by a pair of transistors installed at the upper and lower ends of the measuring rod, and converted into an electrical AE signal wave corresponding to the AE wave. Based on the analysis of the AE signal wave, the position of occurrence of displacement in the ground due to the difference in arrival time of the signal to the pair of transducers, the range of occurrence of displacement according to the distribution of the position of displacement, and
A method for measuring displacement in the ground using the acoustic measurement method, which is characterized by determining the displacement velocity based on the rate of occurrence (event rate) of AE signal waves and the amount of displacement based on the cumulative number of occurrences (cumulative number of events). 2. A measuring rod made of a composite of glass fiber and polymeric natural resin (rosin) that generates AE waves that are proportional to displacement and have little propagation attenuation; A.E.
A pair of transducers detect waves and generate corresponding electrical AE signal waves, and the AE signal waves output from the transducers are analyzed to determine the location and range of displacement in the ground. A measuring device for measuring displacement in the ground, comprising a processing system that provides a displacement speed and a displacement amount. 3. The measuring device according to claim 2, wherein the measuring rod comprises a composite of a glass fiber and rosin embedded therein and poured in a molten state and slowly cooled and solidified.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62197929A JPS6439580A (en) | 1987-08-06 | 1987-08-06 | Measuring method for in-ground displacement by acoustic emission method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62197929A JPS6439580A (en) | 1987-08-06 | 1987-08-06 | Measuring method for in-ground displacement by acoustic emission method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6439580A JPS6439580A (en) | 1989-02-09 |
| JPH0523719B2 true JPH0523719B2 (en) | 1993-04-05 |
Family
ID=16382629
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62197929A Granted JPS6439580A (en) | 1987-08-06 | 1987-08-06 | Measuring method for in-ground displacement by acoustic emission method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6439580A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0862337A (en) * | 1994-08-25 | 1996-03-08 | Iwao Nakajima | Measuring device for ae wave |
| WO2009008515A1 (en) * | 2007-07-12 | 2009-01-15 | National Institute Of Advanced Industrial Science And Technology | High-pressure tank damage detecting method and device therefor |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB0901443D0 (en) | 2009-01-29 | 2009-03-11 | Univ Loughborough | Acoustic emission soil slope displacement rate sensor |
| CN113108732B (en) * | 2021-04-13 | 2023-04-07 | 江西理工大学 | Guided wave monitoring method for slope landslide early warning |
| CN115342760B (en) * | 2022-07-22 | 2023-05-16 | 江西理工大学 | Landslide early warning method, system, terminal and storage medium for dumping site |
-
1987
- 1987-08-06 JP JP62197929A patent/JPS6439580A/en active Granted
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0862337A (en) * | 1994-08-25 | 1996-03-08 | Iwao Nakajima | Measuring device for ae wave |
| WO2009008515A1 (en) * | 2007-07-12 | 2009-01-15 | National Institute Of Advanced Industrial Science And Technology | High-pressure tank damage detecting method and device therefor |
| US8240209B2 (en) | 2007-07-12 | 2012-08-14 | National Institute Of Advanced Industrial Science And Technology | Method and apparatus for detecting damage to high-pressure tank |
| JP5158723B2 (en) * | 2007-07-12 | 2013-03-06 | 独立行政法人産業技術総合研究所 | Damage detection method for high-pressure tank and apparatus therefor |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6439580A (en) | 1989-02-09 |
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