JPH0753973B2 - Ground liquefaction prevention method - Google Patents
Ground liquefaction prevention methodInfo
- Publication number
- JPH0753973B2 JPH0753973B2 JP2144453A JP14445390A JPH0753973B2 JP H0753973 B2 JPH0753973 B2 JP H0753973B2 JP 2144453 A JP2144453 A JP 2144453A JP 14445390 A JP14445390 A JP 14445390A JP H0753973 B2 JPH0753973 B2 JP H0753973B2
- Authority
- JP
- Japan
- Prior art keywords
- ground
- liquefaction
- pumping
- groundwater level
- sensor
- 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
Landscapes
- 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)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は例えば護岸部周辺地盤の如き、地下水位の高い
砂質地盤よりなる液状化の可能性のある地盤の地震時に
おける液状化防止方法に係るものである。DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a method for preventing liquefaction of a ground, such as the ground around a revetment, which is composed of sandy ground with a high groundwater level and is likely to be liquefied during an earthquake. It is related to.
（従来の技術） 従来、地震時に地盤の液状化の発生を適確に判定する計
測装置がなかったため、同地盤の周辺域内に設置した揚
水設備で地下水位の低下を図るとともに、所定の水位を
維持するために長期間に亘って揚水設備を稼動させてお
く必要があった。(Prior art) Conventionally, since there was no measuring device that accurately determines the occurrence of liquefaction of the ground at the time of an earthquake, the pumping equipment installed in the surrounding area of the ground aimed to lower the groundwater level and to maintain a predetermined water level. In order to maintain it, it was necessary to keep the pumping equipment operating for a long time.
（発明が解決しようとする問題） 前記従来の方法によれば、揚水設備を長期間に亘って運
転し、維持管理をしなければならず、コストが高くな
る。(Problems to be Solved by the Invention) According to the above-mentioned conventional method, the pumping equipment must be operated for a long period of time to be maintained and managed, resulting in high cost.
また低下させた地下水位を長期間維持させておくので、
地盤沈下等による公害の惧れが生じる。そのため、場所
によっては適用不可能となる。Also, because the lowered groundwater level is maintained for a long time,
There is a risk of pollution due to land subsidence. Therefore, it is not applicable in some places.
本発明は前記従来技術の有する問題点に鑑みて提案され
たもので、その目的とする処は、地震時に、地盤におけ
る液状化の発生個所を早期に把握して揚水装置を連動せ
しめ、地盤の液状化を未然に防止する方法を提供する点
にある。The present invention has been proposed in view of the problems of the prior art, the purpose of the purpose is to grasp the location of liquefaction in the ground early in the event of an earthquake to make the pumping device interlock, The point is to provide a method for preventing liquefaction.
（課題を解決するための手段） 前記の目的を達成するため、本発明に係る地盤の液状化
防止方法によれば、液状化の可能性のある地盤内に、２
個所にAEセンサーが配設された金属棒を配置し、同両AE
センサーによって地盤内のAE現象を検出して地盤内の液
状化を検出し、同検出信号に連動して前記地盤周辺域に
設置した揚水装置を作動させて地下水位を低下せしめる
ものである。(Means for Solving the Problem) In order to achieve the above-mentioned object, according to the method for preventing liquefaction of ground according to the present invention, the
Place a metal rod with an AE sensor at each location
The sensor detects the AE phenomenon in the ground to detect the liquefaction in the ground, and operates the pumping device installed in the surrounding area of the ground in conjunction with the detection signal to lower the groundwater level.
（作用） 地震時に地盤に作用している土圧と間隙水圧とが等しく
なった場合、土粒子はその土圧と水圧とがバランスして
いるために浮いている状態、即ち液状化状態となる。(Operation) When the soil pressure acting on the ground at the time of an earthquake and the pore water pressure become equal, the soil particles are in a floating state, that is, in a liquefied state because the soil pressure and the water pressure are balanced. .
この場合、土粒子と水の動きが生起して、これに伴って
音のエネルギーが放出されるAE現象（アコーステイツク
エミツシヨンAcoustic Emission）が生起する。In this case, the movement of soil particles and water occurs, accompanied by the emission of sound energy AE phenomenon (Acoustic Emission Acoustic Emission) occurs.
これに伴って前記地盤内に設置された金属棒を介して前
記各AEセンサーでAE現象を検出し、地盤の液状化を検出
し、この検出信号に連動して前記地盤周辺域に設置され
た揚水装置を作動して地下水位を低下せしめる。Accompanying this, the AE phenomenon is detected by each AE sensor through the metal rod installed in the ground, the liquefaction of the ground is detected, and the liquefaction of the ground is detected. Activate the pumping system to lower the groundwater level.
このように本発明によればAE現象を利用して地盤の液状
化の初期段階を検出し、直ちに液状化対策を施すことに
よって、液状化の進行を早期に食い止めることが可能と
なる。As described above, according to the present invention, by utilizing the AE phenomenon to detect the initial stage of liquefaction of the ground and immediately take countermeasures against liquefaction, it is possible to quickly stop the progress of liquefaction.
（実施例） 以下本発明を図示の実施例について説明する。(Examples) The present invention will be described below with reference to illustrated examples.
（Ａ）は護岸部（Ｂ）周辺における地下水位が高く、液
状化現象の生起する可能性の高い砂質地盤、（Ｃ）は液
体貯蔵タンク、（Ｄ）は水域で、前記砂質地盤（Ａ）
に、上下方向に間隔を存してAEセンサー（１）が配設さ
れた金属棒（２）（ウエーブガイド）が設置されてい
る。前記各AEセンサー（１）は夫々ケーブル（３）を介
してAE処理装置（４）に接続され、更に同AE処理装置
（４）はケーブル（３）を介してコンピユータ（５）に
接続され、かくして液状化判定装置（Ｉ）が構成されて
いる。(A) is a sandy ground where the groundwater level around the revetment (B) is high and liquefaction is likely to occur, (C) is a liquid storage tank, (D) is a water area, and the sandy ground ( A)
A metal rod (2) (wave guide) on which an AE sensor (1) is arranged at intervals in the vertical direction is installed. Each of the AE sensors (1) is connected to an AE processing device (4) via a cable (3), and the AE processing device (4) is connected to a computer (5) via a cable (3). Thus, the liquefaction determination device (I) is constructed.
前記コンピユータ（５）はケーブル（３）を介して前記
地盤（Ａ）の周辺に設けられた揚水設備（II）における
制御装置（６）に接続され、同制御装置（６）はケーブ
ル（３）を介して揚水ポンプ（７）に接続されている。The computer (5) is connected via a cable (3) to a control device (6) in a pumping facility (II) provided around the ground (A), and the control device (6) is connected to the cable (3). Is connected to the pumping pump (7).
同揚水ポンプ（７）の吸込管（８）は地盤（Ａ）に埋設
された集水管（９）に接続され、吐出管（10）は河川等
に導かれている。The suction pipe (8) of the pumping pump (7) is connected to the water collection pipe (9) buried in the ground (A), and the discharge pipe (10) is led to a river or the like.
而して地震時において前記地盤（Ａ）が液状化し、土粒
子と水の動きが生じてAE現象が生起すると、前記AEセン
サー（１）によってこれを検出し、同AEセンサー（１）
による検出信号をAE信号かノイズかを判別して、AE信号
のみを取出してAE処理装置（４）に入力し、同AE処理装
置（４）によって前記両AEセンサー（１）からのAE信号
到達時間差や金属棒（２）を伝わる音速、AE信号を検出
したときの音の波形パラメーターを計測し、前記AE処理
装置（４）の計測データをコンピユータ（５）に入力、
演算し、地盤（Ａ）の液状化を判定する。When the ground (A) is liquefied during the earthquake and the movement of soil particles and water occurs to cause the AE phenomenon, the AE sensor (1) detects this and the AE sensor (1)
The detection signal by AE signal or noise is discriminated, only the AE signal is extracted and input to the AE processor (4), and the AE processor (4) arrives at the AE signal from both AE sensors (1). The time difference, the speed of sound transmitted through the metal rod (2), the waveform parameters of the sound when the AE signal is detected are measured, and the measurement data of the AE processing device (4) is input to the computer (5).
The calculation is performed to determine the liquefaction of the ground (A).
而して前記AEセンサー（１）は土粒子と水との微小な動
きによる音を検出することができるので、地盤（Ａ）の
液状化の初期段階を適確に捕えることができる。Since the AE sensor (1) can detect the sound caused by the minute movement between the soil particles and the water, the initial stage of the liquefaction of the ground (A) can be accurately captured.
かくして前記地盤（Ａ）の液状化が判定されると、周辺
域に配置された揚水設備（II）における制御装置（６）
に前記コンピユータ（５）より起動指令を発して、同制
御装置（６）によって前記揚水ポンプ（７）を一定時間
作動せしめ、地下水位の低下を図り、液状化の進行を早
期に食い止める液状化防止策が可能となる。Thus, when the liquefaction of the ground (A) is determined, the control device (6) in the pumping facility (II) arranged in the surrounding area.
A start command is issued from the computer (5), and the pump (7) is operated by the control device (6) for a certain period of time to lower the groundwater level and prevent the progress of liquefaction early. Measures are possible.
前記揚水ポンプ（７）は一定時間起動後に停止するが、
その際、前記液状化判定装置（Ｉ）が液状化を判定して
いる場合には、再び一定時間揚水が行なわれる。The pumping pump (7) stops after starting for a certain time,
At this time, when the liquefaction determination device (I) determines liquefaction, the water is pumped again for a fixed time.
なお前記実施例においては、地盤の液状化防止のため、
土の有効応力の増大を図る手段として揚水し、地下水位
を低下せしめるものであるが、第２図に示すように、砕
石、砂利等の柱を地中に設けたグラベルドレーン（11）
による排水によって、間隙水圧の消散を図って液状化を
防止する場合にも本発明は適用されるので、グラベルド
レーン（11）層内に集水された水を、吸込管（８）を介
して揚水ポンプ（７）によって強制排水することによっ
て、従来よりも、間隙水圧の消散効果を図ることができ
る。In the above examples, to prevent liquefaction of the ground,
The groundwater level is lowered by pumping up as a means to increase the effective stress of soil. As shown in Fig. 2, gravel drains (11) with pillars of crushed stone, gravel, etc.
Since the present invention is also applied to the case where the pore water pressure is dissipated and the liquefaction is prevented by the drainage by, the water collected in the gravel drain (11) layer is collected through the suction pipe (8). The forced drainage by the pumping pump (7) can dissipate the pore water pressure more than before.
（発明の効果） 本発明によれば前記したように、液状化の可能性のある
地盤内に、２個所にAEセンサーが配設された金属棒を配
設し、前記両AEセンサーによって地盤内のAE現象を検出
して地盤内の液状化発生の初期を捕えることができ、こ
の検出信号に連動して前記地盤周辺域に設置した揚水装
置を作動させて地下水位を低下せしめるようにしたの
で、液状化発生の初期段階で敏速に対応し、液状化防止
効果を挙げることができる。(Effects of the Invention) According to the present invention, as described above, a metal rod having an AE sensor is provided at two locations in the ground that is likely to be liquefied, and the inside of the ground is protected by both the AE sensors. It is possible to detect the AE phenomenon of the above and detect the initial stage of liquefaction occurrence in the ground, and in conjunction with this detection signal, the pumping equipment installed in the surrounding area of the ground is operated to lower the groundwater level. The liquefaction prevention effect can be achieved by promptly responding to the liquefaction at the initial stage.
また前記揚水装置は液状化が判定されたときだけ一時的
に作動するので、効率的な運転、維持管理が行なわれる
と同時に、地下水位低下に伴う地盤沈下等に公害が発生
する惧れがない。In addition, since the pumping system operates temporarily only when liquefaction is determined, efficient operation and maintenance can be performed, and at the same time, there is no risk of pollution such as ground subsidence due to lowering of groundwater level. .
第１図は本発明に係る地盤の液状化防止方法の一実施例
の実施状況を示す縦断面図、第２図は本発明をグラベル
ドレーンによる排水方法に適用した実施例の実施状況を
示す縦断面図である。 （Ｉ）…液状化判定装置、（II）…揚水設備、（Ａ）…
砂質地盤、（１）…AEセンサー、（２）…金属棒、
（３）…ケーブル、（４）…AE処理装置、（５）…コン
ピユータ、（６）…制御装置、（７）…揚水ポンプ、
（８）…吸込管、（９）…集水管、（10）…吐出管。FIG. 1 is a vertical sectional view showing an embodiment of an embodiment of a method for preventing liquefaction of ground according to the present invention, and FIG. 2 is a longitudinal section showing an embodiment of an embodiment in which the present invention is applied to a drainage method using a gravel drain. It is a side view. (I) ... Liquefaction determination device, (II) ... Pumping equipment, (A) ...
Sandy ground, (1) ... AE sensor, (2) ... Metal rod,
(3) ... Cable, (4) ... AE processing device, (5) ... Computer, (6) ... Control device, (7) ... Pumping pump,
(8) ... Suction pipe, (9) ... Water collection pipe, (10) ... Discharge pipe.
Claims (1)
AEセンサーが配設された金属棒を設置し、同両AEセンサ
ーによって地盤内のAE現象を検出して地盤内の液状化を
検出し、同検出信号に連動して前記地盤周辺域に設置し
た揚水装置を作動させて地下水位を低下せしめることを
特徴とする地盤の液状化防止方法。1. At two locations in the ground where liquefaction is possible
A metal rod equipped with an AE sensor is installed, and both AE sensors detect the AE phenomenon in the ground to detect liquefaction in the ground, and install it in the surrounding area of the ground in conjunction with the detection signal. A method for preventing liquefaction of ground, comprising operating a pumping device to lower the groundwater level.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2144453A JPH0753973B2 (en) | 1990-06-04 | 1990-06-04 | Ground liquefaction prevention method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2144453A JPH0753973B2 (en) | 1990-06-04 | 1990-06-04 | Ground liquefaction prevention method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0438319A JPH0438319A (en) | 1992-02-07 |
| JPH0753973B2 true JPH0753973B2 (en) | 1995-06-07 |
Family
ID=15362600
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2144453A Expired - Fee Related JPH0753973B2 (en) | 1990-06-04 | 1990-06-04 | Ground liquefaction prevention method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0753973B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2528743B2 (en) * | 1991-02-07 | 1996-08-28 | 株式会社奥村組 | Ground improvement method and drain device |
| CN102926393A (en) * | 2012-11-22 | 2013-02-13 | 河海大学 | Vacuum water pumping device for treating liquefaction of building foundation and construction method |
| CN103061324A (en) * | 2013-01-28 | 2013-04-24 | 河海大学 | Underground-inflated liquefied foundation treating device and construction method |
| JP6365979B2 (en) * | 2014-09-24 | 2018-08-01 | 五洋建設株式会社 | How to prevent ground liquefaction |
-
1990
- 1990-06-04 JP JP2144453A patent/JPH0753973B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0438319A (en) | 1992-02-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |