JP2011059064A - State evaluation method for structure using ultra-low frequency sound measurement - Google Patents
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Abstract
Description
本発明は超低周波音測定による構造体の状況評価方法に係り、特に自然圏において発生し、地盤やコンクリート構造物等の構造体を伝播する超低周波音パルスの検知および解析を行うことで、自然圏における自然現象、伝播する構造体の地盤の状況等を、簡易に把握し、評価できる超低周波音測定による構造体の状況評価方法に関する。 The present invention relates to a method for evaluating the state of a structure by measuring ultra-low frequency sound, particularly by detecting and analyzing ultra-low frequency sound pulses that occur in the natural zone and propagate through structures such as the ground and concrete structures. Further, the present invention relates to a method for evaluating the state of a structure by means of ultra-low frequency sound measurement capable of easily grasping and evaluating a natural phenomenon in the natural sphere, a ground state of a propagating structure, and the like.
従来、生活圏で生じている各種の低周波音の問題については、その発生源の特定方法、対象騒音の測定方法、防止技術、及び対策技術が確立されている（非特許文献１，２）。 また、低周波音の場合に適用可能な音圧レベルの測定方法とその装置（特許文献１）が提案されている。
Conventionally, for various low-frequency sound problems occurring in the living area, a method for identifying the source, a method for measuring the target noise, a prevention technique, and a countermeasure technique have been established (Non-Patent
これに対して、出願人は、自然圏において生じるいわゆる自然現象に起因して発生する、２０Hz以下の超低周波音パルスについて、各種の事例観測と研究とを進めてきた。たとえば、火山活動の観測、土砂崩壊前兆現象の観測、河川掃流砂量等の自然外力の観測を例にその研究を行ってきた。また、構造体の劣化状態等の状況観察に着目した観測も行ってきた。たとえば橋梁等の土木構造物や、風力発電施設の基礎地盤に問題がある場合は、列車荷重列、車両走行、風荷重等によって、自然外力と同様の低周波音がこれら構造体において発生し、伝播することを見出している。これらの構造体での反応は、自然現象の観測のような連続的線形的な反応ではなく、間欠的なパルス反応であった。 On the other hand, the applicant has advanced various case observations and researches on ultra-low frequency sound pulses of 20 Hz or less, which are caused by so-called natural phenomena occurring in the natural sphere. For example, we have been conducting research on volcanic activity, observations of landslide precursors, and observations of natural external forces such as river stream sand. We have also made observations focusing on the observation of the state of deterioration of structures. For example, when there is a problem with civil engineering structures such as bridges and the foundation ground of wind power generation facilities, low frequency sound similar to natural external force is generated in these structures due to train load train, vehicle travel, wind load, etc. It is found to propagate. The reaction in these structures was not a continuous linear reaction as observed in natural phenomena, but an intermittent pulse reaction.
上述したように、出願人は、超低周波音が周辺環境に及ぼす影響の調査、研究を行ってきた経験から、対象としている超低周波音は、連続する発生音ではなく、パルスとしての間欠的な発生音であり、その超低周波音パルスの特性として、以下の点を考慮した計測を行うことが重要であることを知見として得た。
（1）パルスとしての発生音の継続時間は１秒以内である。
（2）音圧強度は場所により異なり、当然大きな幅を持っており、100〜200,000μPaの範囲のデータが出現する。
（3）バックグラウンド音圧値（当該地点の暗騒音）の平均値＋３.５×偏差よりも値の大きい計測値をパルス音とする。
（4）卓越周波数は数Hz〜８０Hzである。
（5）パルス音が連続的に発生しても、その発生周期は１０〜１５secである。また、その場合の連続時間は自然現象の観測の経験上、数分以内が多い。
As described above, from the experience of investigating and researching the influence of ultra-low frequency sound on the surrounding environment, the applicant has identified that the target ultra-low frequency sound is not a continuous generated sound but an intermittent pulse. As the characteristics of the ultra-low frequency sound pulse, it was learned that it was important to perform measurement in consideration of the following points.
(1) The duration of the sound generated as a pulse is within 1 second.
(2) The sound pressure intensity varies from place to place and naturally has a large width, and data in the range of 100 to 200,000 μPa appears.
(3) The average value of the background sound pressure value (background noise at the relevant point) + 3.5 × the measured value greater than the deviation is the pulse sound.
(4) The dominant frequency is several Hz to 80 Hz.
(5) Even if the pulse sound is continuously generated, the generation period is 10 to 15 seconds. In addition, the continuous time in that case is often within a few minutes based on experience in observing natural phenomena.
本発明は、これら超低周波音のパルス反応についての知見をもとにするものである。なお、本明細書では、これを「超低周波音パルス」と呼ぶ。 The present invention is based on the knowledge about the pulse response of these ultra-low frequency sounds. In the present specification, this is referred to as “ultra-low frequency sound pulse”.
これらの超低周波パルスの特性を考慮した場合、非特許文献１に開示されたような低周波音圧レベル計によるＧ特性音圧レベルでの測定、１／３オクターブバンドでの音圧レベル測定では、卓越的なデータとしてのパルスの収集が出来ないという問題がある。
In consideration of the characteristics of these ultra-low frequency pulses, measurement at a G characteristic sound pressure level by a low frequency sound pressure level meter as disclosed in
また、出願人（発明者）は、本願発明を完成させるために、自然の観測において計測対象を、音響エネルギー量（W/m2）で求め、dBへの表記を求められる場合は、自然圏での現象をとらえるのに、水中を基準とした方が解析に有効であると考えて、１μPaを０dBとして表記し、周波数特性については、実験等を参考に２０Hzを０dBとして、４０dB/octへ減衰係数を乗じている。そのため、特許文献１に開示された音圧データの量子化におけるロジックとはまったく異なるものとなっている。
In addition, in order to complete the invention of the present application, the applicant (inventor) obtains the measurement object in the natural observation by the amount of acoustic energy (W / m 2 ), and when the notation to dB is required, In order to capture the phenomenon in the water, it is considered that the analysis based on water is more effective for analysis, and 1 μPa is expressed as 0 dB, and the frequency characteristics are set to 40 dB / oct with 20 Hz as 0 dB with reference to experiments. Multiply by the attenuation coefficient. Therefore, the logic in the quantization of sound pressure data disclosed in
そこで、本発明の目的は上述した従来の技術が有する問題点を解消し、計測対象から発生し超低周波音パルスのうち、対象とした超低周波音パルスの卓越周波数と、その音圧エネルギーとに着目し、自然圏での現象観測、パルス音が伝播する構造体の劣化状態等の評価を簡易に行うことができるようにした超低周波音測定による構造体の状況評価方法を提供することにある。 Therefore, the object of the present invention is to solve the above-mentioned problems of the prior art, and among the ultra-low frequency sound pulses generated from the measurement object, the dominant frequency of the targeted ultra-low frequency sound pulse and its sound pressure energy We provide a method for evaluating the state of structures by measuring ultra-low frequency sound, which makes it possible to easily observe phenomena in the natural sphere and evaluate the deterioration state of structures where pulse sound propagates. There is.
上記目的を達成するために、本発明の超低周波音測定による構造体の状況評価方法は、観測対象の構造体で発生あるいは伝播する超低周波音響エネルギーを測定し、該超低周波音響エネルギーの音圧強度と卓越周波数との関係を求め、その数値評価結果をもとに前記観測対象の状況、評価を行うことを特徴とする。 In order to achieve the above object, the method of evaluating the state of a structure by measuring ultra-low frequency sound according to the present invention measures ultra-low frequency acoustic energy generated or propagated in the structure to be observed, and The relationship between the sound pressure intensity and the dominant frequency is obtained, and the condition and evaluation of the observation target are performed based on the numerical evaluation result.
このとき、前記超低周波音響エネルギーはパルス値であり、該パルス値を所定計測間隔で連続計測して、前記観測対象のモニタリングを行うことが好ましい。 At this time, the ultra-low frequency acoustic energy is a pulse value, and it is preferable to monitor the observation target by continuously measuring the pulse value at a predetermined measurement interval.
また、測定点での暗騒音平均音圧強度＋偏差×３．５より大きい測定値を、超低周波音のパルス値とすることが好ましい。 Moreover, it is preferable that a measured value larger than the average sound pressure intensity of the background noise + deviation × 3.5 at the measurement point is a pulse value of the very low frequency sound.
前記超低周波音周波数は、１６Hz以下とすることが好ましい。 The ultra-low frequency sound frequency is preferably 16 Hz or less.
前記観測対象で得られた複数データの超低周波周波数（Hz）-1と、ピーク超低周波音圧強度ピーク低周波音音圧強度（×１０-8W/m2）1/2との相関関係を図示し、その状況評価を行うことが好ましい。 The ultra-low frequency (Hz) −1 of multiple data obtained from the observation object and the peak ultra-low frequency sound pressure intensity peak low-frequency sound pressure intensity (× 10 −8 W / m 2 ) 1/2 It is preferable to illustrate the correlation and evaluate the situation.
本発明によれば、自然圏において発生し、地盤やコンクリート構造物等の構造体を伝播する超低周波音パルスの測定および、そのピーク音圧強度、卓越周波数からの解析を行うことで、自然圏における自然現象、伝播する構造体の地盤の状況等を簡易に把握し、評価することができるという効果を奏する。 According to the present invention, the measurement of ultra-low frequency sound pulses that occur in the natural zone and propagate through structures such as the ground and concrete structures, and the analysis from the peak sound pressure intensity and dominant frequency, There is an effect that it is possible to easily grasp and evaluate a natural phenomenon in a sphere, a ground state of a propagating structure, and the like.
以下、本発明の超低周波音測定による構造体の状況評価方法の実施するための形態として、以下の実施例について添付図面を参照して説明する。 Hereinafter, the following examples will be described with reference to the accompanying drawings as a mode for carrying out the structure state evaluation method according to the ultra-low frequency sound measurement of the present invention.
図１は、本発明の超低周波音測定による構造体の状況評価方法に用いる計測出力器、解析装置の概略構成を示したブロック構成図である。同図に示したように、計測出力器１０は、地中に埋設可能な防水タイプのマイクロホン１からの信号を受信可能な、ボックスタイプの形態から構成されている。その内部構成は、図１のブロック図に示したように、マイクロホン１で、所定の計測時間間隔で得られた超低周波音パルス信号を増幅する増幅回路１１、周波数帯域別音を計測するバンドパスフィルタ１２及びＡ／Ｄ変換器１３と、搭載されたソフトウエア（アプリケーション）に基づき計測時のパルス信号を６種類の測定データとして出力するように、データ処理可能な周波数・音圧データ解析部１４と、パソコン２０などの解析表示のための周辺機器と接続し、外部へデータ出力するための出力端子１５と、操作手順、解析結果、システム情報等をユーザに伝える表示部１６とから構成されている。周波数・音圧データ解析部１４は、具体的には制御用ＣＰＵ、演算ＲＯＭが装着された制御ボードを備えている。なお、解析、評価には、外部のパソコン２０を用いてもよいし、この解析部１４で測定データ処理に加えて、計測結果の周波数評価まで行えるようにしてもよい。図１に示したノートパソコン２０とのデータ通信にはRS232C,有線、無線の各種LAN方式、携帯電話、ＰＨＳによるパケット通信、メモリー媒体（各種規格カード）接続によるデータ回収等各種のデータ出力手段を採用することができる。
FIG. 1 is a block configuration diagram showing a schematic configuration of a measurement output device and an analysis device used in a structure state evaluation method by ultra-low frequency sound measurement according to the present invention. As shown in the figure, the
［超低周波音パルスの測定］
以下、本発明による超低周波音測定による構造体の状況評価方法の一実施例について、そのパルス測定からモニタリング結果出力までの手順を、図２を参照して説明する。
超低周波音パルスは、計測対象の地盤等の内部に埋設されたマイクロホンを用いて、１５秒を周期に１パルスごとに測定する。具体的には、１Hz〜１000Hzの周波数音をフラット入力可能な圧電素子式の水中マイクロホン１（図１）を利用し、計測時定数（時間重み付け）特性として、５Hzパルスを１波として計測する。このとき、マイクロホンと媒質としての地盤等との間に十分な密着度が得られない場合がある。その点を考慮し、音響エネルギーとして、各測定地点ごとにおいて、その場の暗騒音相対値との比較を行い、音響エネルギー量（W/m2）を計測単位として計測する（図２：ステップ１００、以下Ｓ１００と略記する。）。
[Measurement of ultra-low frequency sound pulses]
Hereinafter, the procedure from the pulse measurement to the monitoring result output will be described with reference to FIG. 2 for one embodiment of the structure evaluation method by the ultra-low frequency sound measurement according to the present invention.
The ultra-low frequency sound pulse is measured for each pulse with a period of 15 seconds using a microphone embedded in the ground or the like to be measured. Specifically, a piezoelectric element type underwater microphone 1 (FIG. 1) capable of flat input of frequency sound of 1 Hz to 1000 Hz is used, and a 5 Hz pulse is measured as one wave as a measurement time constant (time weighting) characteristic. At this time, there may be a case where sufficient adhesion cannot be obtained between the microphone and the ground as a medium. Considering this point, the acoustic energy is compared with the relative background noise relative value at each measurement point, and the amount of acoustic energy (W / m 2 ) is measured as a unit of measurement (FIG. 2: Step 100). Hereinafter abbreviated as S100).
マイクロホンを介して１５秒ごとに測定されたデータのうち、直接計測されるのは、ピーク超低周波音音圧強度Lp（×１０-8W/m2）と、卓越周波数（Hz）である。これら卓越周波数、音圧強度は、出願人が開示した特開２００４−２１９１６８号公報による方法を用いることができる。なお、計測間隔を１５秒としたため、長期のモニタリングが可能になる。その際、Lp＞L（平均）＋偏差×３．５の場合を、超低周波音パルスとして取り扱うことで、測定データ精度向上を図ることができる。 Of the data measured every 15 seconds through the microphone, the peak ultra-low frequency sound pressure intensity Lp (× 10 −8 W / m 2 ) and the dominant frequency (Hz) are measured directly. . The method according to Japanese Patent Application Laid-Open No. 2004-219168 disclosed by the applicant can be used for the dominant frequency and the sound pressure intensity. Since the measurement interval is 15 seconds, long-term monitoring is possible. At that time, the accuracy of measurement data can be improved by treating the case of Lp> L (average) + deviation × 3.5 as an ultra-low frequency sound pulse.
このときの測定周波数帯域のＡ／Ｄ値としては、周波数３Hz（fO）：音圧PO（平均）SDO（偏差）POm（最大値），１０Hz（f1）：P1（平均）SD1（偏差）Plm（最大値），１００Hz（f2）：P2（平均）SD2（偏差）P2m（最大値），３００Hz（f3）：P3（平均）SD3（偏差）P3m（最大値），１０００Hz（f4）：P4（平均）SD4（偏差）P4m（最大値）が求められる。なお、P0m〜P4mは、１０HzのＡ／Ｄ値が最大の時の値とする。 As the A / D value of the measurement frequency band at this time, frequency 3 Hz (fO): sound pressure PO (average) SDO (deviation) POm (maximum value), 10 Hz (f1): P1 (average) SD1 (deviation) Plm (Maximum value), 100 Hz (f2): P2 (average) SD2 (deviation) P2m (maximum value), 300 Hz (f3): P3 (average) SD3 (deviation) P3m (maximum value), 1000 Hz (f4): P4 ( Average) SD4 (deviation) P4m (maximum value) is obtained. Note that P0m to P4m are values when the 10 Hz A / D value is maximum.
さらに、これら以外に周波数・音圧解析部でのデータ処理、解析により、以下の６種類の音圧、周波数を計測し、出力することができる（Ｓ１１０）。
EL：平均低周波音圧強度（×１０-8W/m2）
FL：平均低周波周波数（Hz）
ELm：ピーク低周波音音圧強度（×１０-8W/m2）
FLm：ピーク低周波周波数（Hz）
EH：平均可聴音音圧強度（×１０-8W/m2）
FH：平均可聴音周波数（Hz）
In addition to these, the following six types of sound pressure and frequency can be measured and output by data processing and analysis in the frequency / sound pressure analysis unit (S110).
EL: Average low frequency sound pressure intensity (× 10 -8 W / m 2 )
FL: Average low frequency (Hz)
ELm: Peak low frequency sound pressure intensity (× 10 -8 W / m 2 )
FLm: Peak low frequency frequency (Hz)
EH: Average audible sound pressure intensity (× 10 -8 W / m 2 )
FH: Average audible sound frequency (Hz)
さらに、１０Hz（f1）:P1（平均）,１００Hz（f2）:P2（平均）,３００Hz（f3）:P3（平均）,１０００Hz（f4）:P4（平均）をもとに、計測された超低周波音については、その評価は出力信号値として、
R1：作動
R2：振動音発生
R3：可聴音発生
R4：低周波ピーク特性
の４種の信号として処理される（Ｓ１２０）。なお、R1は作動状態を表示するデータであり、状況を評価（識別）する出力信号としてはR2〜R4が該当する。さらに、これらの信号は、出力器１０から外部のパソコン２０等にデータ転送され、その画面上でその発生状況の定性評価結果が確認できるようになっている（Ｓ１３０〜Ｓ１４０）。このときの評価結果は、以下の表１の算定式を用いて行っている。この算定式のアルゴリズムに適用される各定数及び係数は、計測出力器固有の工場出荷時を基本としているが、ユーザ使用時にコマンド操作により適宜値に設定可能である。表１の算定式において、定数α、β、γは測定対象地盤に応じて設定された地盤特性係数である。現場での地盤試験や経験値から得られた値を採用することができる。係数M00,M01,M02,M03は使用した計測出力器における固有の周波数補正係数であり、製品出荷時に決定し、その後の利用時におけるキャリブレーション結果に応じて適宜調整することができる係数である。
Furthermore, the measured values are based on 10Hz (f1): P1 (average), 100Hz (f2): P2 (average), 300Hz (f3): P3 (average), 1000Hz (f4): P4 (average) For low frequency sound, the evaluation is the output signal value,
R1: Activate
R2: Vibration sound generation
R3: Audible sound generated
R4: Processed as four types of signals having low frequency peak characteristics (S120). Note that R1 is data indicating an operating state, and R2 to R4 correspond to output signals for evaluating (identifying) the situation. Further, these signals are transferred from the
［超低周波音パルス計測の現場適用例］
地盤層、水中などの自然圏とそれに組み込まれるように構築された各種構造体を伝播する超低周波音パルスの発生と伝播については、以下のように、発生原因や発生音の性質を推測し、測定器を設置して超低周波音パルスの効率的な測定を行うことが好ましい。
すなわち、測定対象となる地盤、コンクリート構造物、鋼構造物は複合構造体であり、超低周波音は騒音（空気伝播音）と振動（固体音）との混合中間的なものとして発生することが知られている。また、超低周波音が、車走行荷重、列車移動荷重列、風活荷重、動水圧、自然（地震）等によって発生する場合は、連続線形的ではなく、パルスとして発生するため、パルス音のみを長期計測で収集することで測定精度が向上する。
[Application example of ultra-low frequency sound pulse measurement]
Regarding the generation and propagation of ultra-low frequency sound pulses propagating in the natural zone such as the ground layer and underwater and various structures constructed to be incorporated in it, the cause and nature of the generated sound are estimated as follows. It is preferable to install a measuring instrument and perform efficient measurement of ultra-low frequency sound pulses.
In other words, the ground, concrete structure, and steel structure to be measured are composite structures, and ultra-low frequency sound is generated as an intermediate mixture of noise (air propagation sound) and vibration (solid sound). It has been known. In addition, when ultra-low frequency sound is generated due to vehicle running load, train moving load train, wind-driven load, dynamic water pressure, natural (earthquake), etc., it is not continuous linear, but as a pulse, so only the pulse sound Measurement accuracy is improved by collecting long-term measurements.
[測定結果の判定・評価]
図３は、モニタリング結果出力として、上記測定結果を用いて、超低周波周波数（Hz）-1と、ピーク超低周波音圧強度ピーク低周波音音圧強度（×１０-8W/m2）1/2との相関関係を示し、その相関関係の強度に応じた注意レベルの傾向を直観的に把握できるようにした関係グラフである。この判定・評価のために、同図のグラフ領域を、ピーク超低周波音圧強度、周波数がともに低い［通常レベル１］と、ピーク超低周波音圧強度が高く、周波数が低い［通常レベル２］と、ピーク超低周波音圧強度が低く、周波数が高い［注意レベル］と、ピーク超低周波音圧強度と周波数がともに高い、［警戒レベル］に領域分けしている。［通常レベル１］、［通常レベル２］を設定したのは、同じ周波数でも音圧強度が大きい方が高い注意度を要することを意味している。測定されたデータ群の傾向により、測定点での状況をおおよそ判定、評価することができる。これらの評価結果はパソコン２０等で画像表示、あるいはプリンタ（図示せず）出力することが好ましい。これにより、対象構造体の状況評価を直観的に行うことができる。
[Judgment and evaluation of measurement results]
FIG. 3 shows the result of the above measurement as an output of the monitoring result, using the ultra low frequency frequency (Hz) −1 and the peak ultra low frequency sound pressure intensity peak low frequency sound pressure intensity (× 10 −8 W / m 2). ) This is a relationship graph that shows the correlation with 1/2, and enables intuitive grasp of the tendency of attention level according to the strength of the correlation. For this judgment / evaluation, the graph area of the figure is divided into the peak ultra-low frequency sound pressure intensity and frequency [normal level 1], the peak ultra-low frequency sound pressure intensity is high, and the frequency is low [normal level]. 2], the peak ultra-low frequency sound pressure intensity is low and the frequency is high [attention level], and the peak ultra-low frequency sound pressure intensity and frequency are both high and the alarm level is divided. The setting of [normal level 1] and [normal level 2] means that a higher degree of attention is required when the sound pressure intensity is large even at the same frequency. The situation at the measurement point can be roughly determined and evaluated based on the tendency of the measured data group. These evaluation results are preferably displayed on the
本発明の特徴、効果を明確にするために、以上に述べた状況評価方法を、実際の構造体に適用した例について、簡単に説明する。
（超低周波音の発生原因と状況評価）
超低周波音の状況評価の前提として、出願人は、超低周波音の発生原因について、以下の点を認識している。たとえば、構造体としてのコンクリート構造物と地盤との間の緩みがある場合、１０Hz程度の超低周波音が発生し、音圧エネルギーが上昇する。このため、測定結果を適正に引き出すことで、その緩み状態や進行の傾向を把握できる。たとえば、橋梁において下部基礎の支持力が不十分な場合や、河川構造物の底板下や堤体の抜け上がりで生じた空隙でパイピング現象が生じた場合、新しいマグマの貫入により既存の溶岩ドームが破損して火山ガス放出がなされる揚合、断層（アスペリティ）が剥がれ滑り始める時などに、超低周波音パルスが顕著に計測される。よって、このような現場に本発明を適用することで、その現場の構造体（地盤、構造物など）の状況評価を確実に行うことができる。
In order to clarify the features and effects of the present invention, an example in which the situation evaluation method described above is applied to an actual structure will be briefly described.
(Evaluation of the cause of ultra-low frequency sound and evaluation of the situation)
As a premise for evaluating the situation of ultra-low frequency sound, the applicant has recognized the following points regarding the cause of the occurrence of ultra-low frequency sound. For example, when there is a looseness between a concrete structure as a structure and the ground, an extremely low frequency sound of about 10 Hz is generated, and sound pressure energy increases. For this reason, it is possible to grasp the loose state and the tendency of progress by properly drawing out the measurement result. For example, if the bearing capacity of the lower foundation is insufficient in a bridge, or if piping occurs due to a gap created by the bottom plate of a river structure or the rise of a levee, the existing lava dome is replaced by the penetration of new magma. Ultra-low frequency sound pulses are prominently measured when ruptures occur and volcanic gas is released, or when faults (asperities) come off and begin to slip. Therefore, by applying the present invention to such a site, it is possible to reliably evaluate the situation of the structure (ground, structure, etc.) at that site.
（現場適用例：下水管路の劣化状態）
劣化した構造物に自動車等の移動荷重列等が加わることで、超低周波音が発生することから、道路に沿って埋設された下水管路の健全箇所と、要工事箇所とで劣化状態の対比モニタリングを行った。要工事箇所である地点Ｘと複数対比点（健全箇所）とで超低周波音パルスの計測を行った。その結果、地点Ｘでは、各対比点に比較し、大きな音圧エネルギーが発生しており、中間測定点において、さらに低い低周波領域の音圧エネルギーが観測された。また、健全箇所では、ほとんど超低周波音圧は測定されなかった。
(Application example: Degraded state of sewage pipes)
When a moving load train such as an automobile is added to a deteriorated structure, an ultra-low frequency sound is generated. Therefore, the soundness of the sewage pipes buried along the road and the necessary construction points are deteriorated. Contrast monitoring was performed. Ultra-low frequency sound pulses were measured at point X, which is a construction point requiring construction, and a plurality of contrast points (sound points). As a result, at point X, a larger sound pressure energy was generated than at each contrast point, and a lower sound frequency energy in the low frequency region was observed at the intermediate measurement point. Moreover, very low frequency sound pressure was hardly measured in the healthy place.
このように、要工事箇所とは異なる理由で、超低周波音の発生が認められたのは管路のジョイント部であり、ジョイント部にズレ等の何らかの問題が生じている可能性を示唆している。超低周波音が計測されない点は、路盤面に工事跡等もなく一様に状態が良好な箇所や、信号の無い計測区間であった。後者では車輌が速度一定に通過するため、劣化程度はほとんどない。これらのことから、地中埋設物の構造状況、劣化状況とともに地盤自体の健全度の度合いが合わせて反映可能なことが明らかになった。 In this way, it is the joint part of the pipeline that generated ultra-low frequency sound for reasons that are different from the construction work required, suggesting that there may be some problem such as misalignment in the joint part. ing. The point where the ultra-low frequency sound is not measured is a place where there is no work mark on the roadbed surface and the state is uniformly good or a measurement section where there is no signal. In the latter, the vehicle passes at a constant speed, so there is almost no deterioration. From these, it became clear that the degree of soundness of the ground itself can be reflected together with the structural status and deterioration status of the buried objects.
このように、超低周波音圧と周波数をモニタリングし、周波数解析することにより、下水道施設等の要精密点検や要補修判断等の状態監視を簡易・安価で行うことができる。
モニタリングを行う施設等の詳細としては、下水管路の破損やジョイント部の変位の他に、地盤改良工事における薬液注入工程の診断等への活用が望める。
In this way, by monitoring the ultra-low frequency sound pressure and frequency and analyzing the frequency, it is possible to easily and inexpensively monitor the state of a sewerage facility or the like, such as a precise inspection or determination of repair required.
As for the details of facilities to be monitored, in addition to breakage of sewer pipes and displacement of joints, it can be used for diagnosis of chemical injection process in ground improvement work.
なお、本発明は上述した実施例に限定されるものではなく、各請求項に示した範囲内での種々の変更が可能である。すなわち、請求項に示した範囲内で適宜変更した技術的手段を組み合わせて得られる実施形態も、本発明の技術的範囲に含まれる。 In addition, this invention is not limited to the Example mentioned above, A various change within the range shown to each claim is possible. In other words, embodiments obtained by combining technical means appropriately changed within the scope of the claims are also included in the technical scope of the present invention.
１ マイクロホン
１０ 計測出力器
２０ パソコン
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| JP2015025702A (en) * | 2013-07-25 | 2015-02-05 | 株式会社東京建設コンサルタント | Measuring apparatus |
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