JP3803470B2 - Ground fracture prediction method - Google Patents
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- JP3803470B2 JP3803470B2 JP25140697A JP25140697A JP3803470B2 JP 3803470 B2 JP3803470 B2 JP 3803470B2 JP 25140697 A JP25140697 A JP 25140697A JP 25140697 A JP25140697 A JP 25140697A JP 3803470 B2 JP3803470 B2 JP 3803470B2
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Description
【０００１】
【発明の属する技術分野】
本発明は、盛土や切土等による斜面工事やトンネル掘削等の各種土木工事により不安定になると予想される地盤、あるいは風化等により成層が不安定になっていると予想される地盤において、地すべりや土砂崩れ、トンネル切羽の破壊といった地盤破壊現象の発生を予知するための技術に関するものである。
【０００２】
【従来の技術】
地盤組織の安定した自然斜面でも、土や岩を削り取ったり盛土したりして土木工事を行った場合には、施工中、あるいは施工後の経時変化によって表層部が不安定になり、地すべりや土砂崩れ、土石流等の斜面崩壊を発生する恐れがある。またトンネル掘削工事においては、覆工により支保したトンネル空間と掘削予定部分との境界である切羽及びその上側の地盤が最も不安定であるため、この切羽においてトンネルを押し潰すような崩壊が発生しやすい。
【０００３】
したがって従来、切土や盛土等による法面や斜面の工事あるいはトンネル掘削等、各種土木工事においては、施工中あるいは施工後において上述のような地滑りや切羽破壊等による危険を回避するため、工事によって地盤が不安定になると予想される地盤領域（以下、予知対象地盤領域という）に、地滑り計や傾斜計等のように地盤の変位を計測可能なセンサを設置し、これによって計測される前記予知対象地盤領域内の地盤変位量の大きさから地盤破壊が発生する危険性の有無を判断していた。
【０００４】
【発明が解決しようとする課題】
しかし、上記従来の技術においては、地盤変位センサの設置箇所を的確に決定することが困難であり、また、工事によって地盤に生じる歪応力による土塊の変位量や傾斜量は、地質や計測位置によって大きく異なるため、地盤破壊の発生時期を予想することも困難である。
【０００５】
また、担当官庁や市町村においては、土石流災害危険地域や急斜面崩壊危険地域として比較的広範囲の領域が指定されているが、このような広範囲の指定領域のうち、どの領域で実際に災害が発生する危険性が高いかを判定することは現状では非常に困難である。例えば台風等に伴う集中豪雨や比較的長時間に及ぶ地雨性降水等による斜面崩壊の発生位置及び発生時間を予知することは殆ど不可能であった。
【０００６】
本発明は、上記のような事情のもとになされたもので、その技術的課題とするところは、斜面工事やトンネル掘削等による人工改変地盤の破壊の予知を容易に行うことができ、かつその予知の信頼性を高めることにある。
【０００７】
【課題を解決するための手段】
本発明に係る地盤の破壊予知方法は、鉱物などに圧縮力、張力あるいは剪断力等による歪を与えたときの地電位差（地電流）の変化を利用して、土木工事等による人工改変地盤の破壊の予知を行うもので、地震予知のための有効な手段であると言われているＶＡＮ法を応用したものである。すなわち、予め特定可能な、不安定又は不安定になると予想される予知対象地盤領域における地盤の破壊予知方法であって、前記予知対象地盤領域を通る任意の方向に一以上の主測線を設定し、この主測線の両端となる位置で地中に電極を埋設して両電極間で発生する地盤の歪による地電位差を経時的に計測し、前記予知対象地盤領域から離れた安定地盤領域に一以上のノイズ測線を設定してその両端となる位置で地中に電極を埋設し、このノイズ測線で計測される信号をすべてノイズとみなして、主測線で計測される信号から除去することにより前記予知対象地盤領域の歪応力に対応した地盤歪信号を得て、この地盤歪信号の変化から、前記予知対象地盤領域の破壊前兆現象を把握する。なお本発明でいう「地盤」とは、土層や礫層からなる地盤のほか、岩石が主体の岩盤も含めて総称するものである。
【０００８】
ＶＡＮ法による地震予知は、よく知られているように、地震の発生に先行して地下数十ｋｍといった深さの地殻内部で歪応力の増大による岩石の微小破壊に伴う地電位差の変化を計測することによって、地震の発生時期や震源を予測しようとするもので、例えば、ある計測点でしか有意な地電流変化が計測されなかった場合、地震はこの計測点の近傍を震源として発生するものと予測される。これに対して本発明では、例えば斜面・法面工事やトンネル掘削工事等により不安定となる予知対象地盤領域は工事の種類によって予め特定でき、また風化等によって不安定になっていると予想される予知対象地盤領域も予め特定できるので、この予知対象地盤領域での地電位差の変化から、斜面崩壊や切羽の崩壊といった地盤破壊につながる前兆現象が発生しているか否かを、実際の地盤破壊の発生する前に検知し、これによって人的被害を未然に防ぐための有効な対策を早期に講じることを目的としている。
【０００９】
また、地電位差の計測信号には、工場や家庭の電気機器あるいは電車等からの漏洩電気や電磁波等のように、人間の活動に起因するノイズや、地磁気あるいは地下水の変化等に伴う地電流の変化によるノイズが含まれており、このような場合は、ノイズをほぼ完全に除去しないと予知対象地盤領域の歪応力に対応した地電位差（地盤歪信号）の変化を的確に判別することが困難である。したがって、本発明では、予知対象地盤領域から離れた安定地盤領域に一以上のノイズ測線を設定してその両端となる位置で地中に電極を埋設し、このノイズ測線で計測される信号をすべてノイズとみなして、主測線で計測される信号から除去することにより、前記地盤歪信号を得る。
【００１０】
すなわち、予知対象地盤領域の歪応力による地盤歪信号の変化は局地的であるのに対し、例えば地磁気の変化等によるノイズは主測線の電極間での計測信号及びノイズ測線の電極間での計測信号の双方に同時に現れる、というようないくつかの特徴があるため、これらの計測信号の比較によってノイズを識別・除去することができる。
【００１１】
【発明の実施の形態】
図１及び図２は、本発明に係る地盤の破壊予知方法を切土斜面の滑り破壊の予知に適用した第一の実施形態を示すもので、まず図１において、参照符号Ｓは図中一点鎖線で示す自然斜面を有する地盤Ｇを切土することによって施工した切土斜面、ＧＷＬは前記地盤Ｇ中の地下水位である。このような切土斜面Ｓは、安定とされる斜面角度が施工前に予め計算により決定され、アンカーや植栽による適切な斜面補強手段が施されるが、地震加速度等の外力や、長期降雨による含水率の上昇、寒冷地における霜柱の発生や地下水の凍結とその融解の繰り返しによる風化作用等、種々の要因によって、施工中あるいは施工後に地盤が不安定になることがあり、このような場合は、切土斜面Ｓの法肩ＳH から法尻ＳL にかけての地盤内部に円弧面状の滑り面ＬＳを形成するような大規模な表層滑り破壊や、大規模落石等が発生しやすくなる。
【００１２】
したがってこの実施形態においては、切土斜面Ｓと、想定される滑り面ＬＳとの間の地盤を予知対象地盤領域ＧA として、図２に示すように、この予知対象地盤領域ＧA を法肩ＳH 及び法尻ＳL とほぼ直交する方向に横断する複数の主測線Ｌ1 を適当な間隔で設定し、法肩ＳH 及び法尻ＳL のうち、前記予知対象地盤領域ＧA の両側に位置する各主測線Ｌ1 の両端に相当する部分に、図１に示すように電極１，２を埋設し、この電極１，２に導線３及び図示されていない増幅器を介して電流計（例えば高精度のテスタ）４を接続して前記電極１，２間の地電位差を計測する。
【００１３】
一方、滑り破壊等が発生する可能性が全くない安定地盤領域ＧB には、除去対象のノイズの波長等を考慮した、長さの互いに異なるノイズ測線Ｌ2 を一組として、それぞれ複数箇所に、互いに異なる方向に設定し、各ノイズ測線Ｌ2 の両端に相当する地盤表層部には電極５，６を埋設し、主測線Ｌ1 と同様にして地電位差を計測する。各主測線Ｌ1 の電極１，２間において計測される地電位差の信号は、予知対象地盤領域ＧA の歪応力に対応した地盤歪信号と、地磁気の変化や市街地からの電磁波等によるノイズが混在したものであるのに対し、各ノイズ測線Ｌ2 の電極５，６間では予知対象地盤領域ＧA の歪応力による地盤歪信号は殆ど計測されないから、ここでの計測信号は、その全てをノイズとみなすことができる。したがってこのノイズ計測信号を用いて主測線Ｌ1 での計測信号をフィルタリングすることにより、精度の良い地盤歪信号を取り出すことができる。
【００１４】
このようにして計測される地盤歪信号は、通常は振幅が数ｍＶ〜数十ｍＶのオーダーの緩やかな変化を示すが、地盤内部の滑り面ＬＳに作用する剪断応力が増大して、この滑り面ＬＳに沿った土組織の微小破壊を生じると、前記地盤歪信号の振幅は数十〜数百ｍＶのオーダーで変化するようになる。そして予知対象地盤領域ＧA の崩壊（滑り面ＬＳでの表層滑り破壊）は、このような大振幅の地盤歪信号パターン（地盤破壊前兆信号）が一定時間継続して計測された後に発生するものと推定される。
【００１５】
したがって、切土斜面Ｓの着工前に、予知対象地盤領域ＧA となる地盤から予めボーリングによって円柱コア状の地盤サンプルを採取し、室内試験によって、この地盤サンプルに含水率を変える等の種々の条件のもとで圧縮力、張力あるいは剪断力等による歪を与えて、前記予知対象地盤領域ＧA における歪量と地盤歪信号との相関関係を把握しておけば、破壊の規模や時期を推定するのに有効である。また、振幅の大きな地盤破壊前兆信号が、複数の主測線Ｌ1 のうちの一部でのみ計測された場合は、その主測線の近傍で予知対象地盤領域ＧA の崩落が最も発生しやすくなっているものと推定される。
【００１６】
次に図３は、本発明に係る地盤の破壊予知方法をトンネルの切羽破壊の予知に適用した第二の実施形態を示すもので、参照符号Ｔはトンネルであり、ＴA はトンネル内壁を支保するためのトンネル覆工体、ＴB はトンネル先端の掘削面（切羽という）で、このトンネルＴは、更に図中一点鎖線で示すように掘進されて行くものである。トンネルＴの掘削においては切羽ＴB 及びその近傍の上部地盤が最も不安定であり、しかも丘ＧＨのように地表が局部的に高くなっている部分の地下を掘進する過程では、切羽ＴB に作用する土圧が大きくなって、前記切羽ＴB 及びその近傍の上部地盤の不安定度が増大することになる。
【００１７】
したがってこの実施形態においては、丘ＧH の真下にさしかかった切羽ＴB 及びその近傍の上部地盤を予知対象地盤領域ＧC とし、この予知対象地盤領域ＧC の前後方向に延びる一乃至複数の主測線を設定し、その両端であって丘ＧＨの両側の麓に相当する地盤表層部に電極１，２を埋設し、この電極１，２に導線３及び図示されていない増幅器を介して電流計（例えば高精度のテスタ）４を接続して前記電極１，２間の地電位差を計測する。また、トンネルＴの上部地盤領域から離れた安定地盤領域（図示省略）にノイズ測線を先の第一の実施形態と同様に設定し、ここでの計測信号をノイズとみなしてフィルタリングすることにより、前記電極１，２間での計測信号から地盤歪信号を取り出す。
【００１８】
上述した第一及び第二の実施形態においては、防災の観点から、地盤歪信号の振幅が所定の閾値を超えて増大して地盤破壊の前兆を示した場合に警報を発する警報装置を設けることが一層好ましい。
【００１９】
なお、本発明の地盤の破壊予知方法は、上述した切土斜面の滑り破壊やトンネルの切羽破壊の予知以外にも、盛土による堤体の破壊予知等、種々の人工改変地盤の破壊予知方法として適用可能である。
【００２０】
また、担当官庁や市町村において比較的広範囲に指定された土石流災害危険地域や急斜面崩壊危険地域でも、例えば斜面の低位側と高位側に電極を埋設した複数の主測線及び安定領域でのノイズ測線を設定し、上述と同様にして地電位差による地盤歪信号を計測することによって、例えば台風等に伴う集中豪雨や比較的長時間に及ぶ地雨性降水等による斜面崩壊の発生位置及び発生時間をある程度特定することが可能になる。また、これによって市町村長が住民に対して避難の勧告を行ったり、避難地域を指定するためのデータを提供することができる。
【００２１】
【発明の効果】
本発明によると、次のような効果が実現される。
(1) 地中の電極間で計測される地電位差によって地盤の歪応力の変化による地盤破壊を予知できるので、低コストで実施可能である。
(2) ノイズの除去が容易であるため、地盤歪信号により地盤破壊の前兆現象を把握して精度の高い地盤破壊予知を行うことができる。
(3) 複数の主測線における計測データの比較によって、危険性の最も高い場所を特定することができ、データの蓄積によって地盤崩壊の発生時期もある程度予測可能になる。
【図面の簡単な説明】
【図１】本発明に係る地盤の破壊予知方法を切土斜面の滑り破壊の予知に適用した第一の実施形態を示す説明図である。
【図２】上記第一の実施形態における測線の平面配置を示す説明図である。
【図３】本発明に係る地盤の破壊予知方法をトンネルの切羽破壊の予知に適用した第二の実施形態を示す説明図である。
【符号の説明】
１，２，５，６ 電極
４ 電流計
ＧA ，ＧC 予知対象地盤領域
ＧB 安定地盤領域[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a landslide that is expected to become unstable due to various civil works such as slope construction or tunnel excavation due to embankment or cutting, or where stratification is expected to be unstable due to weathering or the like. The present invention relates to technology for predicting the occurrence of ground destruction phenomena such as landslides, landslides, and destruction of tunnel faces.
[0002]
[Prior art]
Even when a natural slope with a stable ground structure is used, when civil engineering work is carried out by cutting or embankment of soil or rock, the surface layer becomes unstable due to changes over time during or after construction, resulting in landslides and landslides. There is a risk of slope failure such as debris flow. Also, in tunnel excavation work, the face that is the boundary between the tunnel space supported by the lining and the planned excavation part and the ground above it are the most unstable. Cheap.
[0003]
Therefore, conventionally, in various civil engineering work such as slope or slope construction by cutting or embankment, tunnel excavation, etc., in order to avoid danger due to landslide or face destruction as described above during or after construction, The prediction that is measured by installing a sensor that can measure the displacement of the ground, such as a landslide meter or inclinometer, in the ground area where the ground is expected to become unstable (hereinafter referred to as the ground area to be predicted). The presence or absence of the risk of ground failure was judged from the amount of ground displacement in the target ground area.
[0004]
[Problems to be solved by the invention]
However, in the above conventional technology, it is difficult to accurately determine the installation location of the ground displacement sensor, and the amount of displacement and inclination of the soil block due to the strain stress generated in the ground due to the construction depends on the geology and measurement position. Because of the large differences, it is difficult to predict when the ground will break down.
[0005]
In addition, in the government offices and municipalities, a relatively wide area is designated as a debris flow disaster risk area or a steep slope failure risk area, but in such a wide range of specified areas, disasters actually occur. It is very difficult to determine whether the risk is high at present. For example, it has been almost impossible to predict the occurrence location and time of slope failure due to torrential rain caused by typhoons or the like, or relatively long-term terrestrial rainfall.
[0006]
The present invention has been made under the circumstances as described above, and the technical problem is that it is possible to easily predict the destruction of artificially modified ground due to slope construction or tunnel excavation, and the like. The purpose is to increase the reliability of the prediction.
[0007]
[Means for Solving the Problems]
The ground failure prediction method according to the present invention uses a change in the ground potential difference (ground current) when a mineral, etc., is distorted by compressive force, tension, shear force, etc. It predicts destruction and applies the VAN method, which is said to be an effective means for earthquake prediction. That is, a method for predicting ground destruction in a ground area to be predicted that can be specified in advance and that is expected to be unstable or unstable, wherein one or more main survey lines are set in an arbitrary direction passing through the ground area to be predicted. Electrodes are buried in the ground at both ends of the main survey line, and the ground potential difference due to the ground strain generated between the two electrodes is measured over time, and it is applied to the stable ground area away from the predicted ground area. By setting the above noise survey line and embedding electrodes in the ground at the positions at both ends thereof, all the signals measured by this noise survey line are regarded as noise and removed from the signal measured by the main survey line. A ground strain signal corresponding to the strain stress in the prediction target ground region is obtained, and a failure phenomenon phenomenon in the prediction target ground region is grasped from a change in the ground strain signal . The term “ground” as used in the present invention is a general term including the ground composed of soil layers and gravel layers as well as rocks mainly composed of rocks.
[0008]
As is well known, earthquake prediction by the VAN method measures changes in the geopotential difference associated with microfractures of rocks due to increased strain stress inside the crust at a depth of several tens of kilometers prior to the occurrence of the earthquake. For example, if a significant change in ground current is measured only at a certain measurement point, the earthquake will occur in the vicinity of this measurement point. It is predicted. On the other hand, in the present invention, for example, a ground area to be predicted that becomes unstable due to, for example, slope / slope work or tunnel excavation work can be specified in advance depending on the type of construction, and is expected to be unstable due to weathering or the like. Therefore, it is possible to determine whether or not there is a precursor phenomenon that leads to ground destruction such as slope failure or face collapse from the change in the ground potential difference in this prediction target ground area. The purpose of this is to detect before the occurrence of this, and to take effective measures to prevent human damage in advance.
[0009]
In addition, the ground potential difference measurement signal includes noise caused by human activities, such as leakage electricity and electromagnetic waves from factories and household electric appliances, trains, etc., and earth currents caused by changes in geomagnetism or groundwater. In such a case, it is difficult to accurately determine the change in the ground potential difference (ground strain signal) corresponding to the strain stress in the ground area to be predicted unless the noise is almost completely removed. It is. Therefore, in the present invention, one or more noise survey lines are set in a stable ground region away from the prediction target ground region, and electrodes are embedded in the ground at positions at both ends thereof, and all signals measured by this noise survey line are The ground strain signal is obtained by considering it as noise and removing it from the signal measured on the main survey line.
[0010]
That is, the change in the ground strain signal due to the strain stress in the ground area to be predicted is local, whereas for example, the noise due to the change in geomagnetism is the measurement signal between the electrodes of the main line and the noise line between the electrodes of the noise line. Since there are some features that appear simultaneously in both measurement signals, noise can be identified and removed by comparing these measurement signals.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 show a first embodiment in which the ground failure prediction method according to the present invention is applied to prediction of sliding failure of a cut slope. First, in FIG. 1, reference numeral S is one point in the figure. A cut slope, GWL, constructed by cutting a ground G having a natural slope indicated by a chain line is a groundwater level in the ground G. For such a cut slope S, a stable slope angle is determined in advance by calculation before construction, and appropriate slope reinforcement means such as anchoring or planting is applied. In some cases, the ground may become unstable during or after construction due to various factors such as increased moisture content due to water, generation of frost columns in cold regions, and weathering caused by repeated freezing and thawing of groundwater. is large and extensive surface slip destruction so as to form a Hokata S H from Hoshiri S sliding surface LS internal arc surface shape of the ground in toward L of Cut slope S, becomes large rock falls, etc. easily occur .
[0012]
Accordingly, in this embodiment, Hokata the Cut slope S, as ground predictive target ground area G A between the sliding surface LS contemplated, as shown in FIG. 2, the prediction target ground area G A a plurality of main survey line L 1 which crosses a direction substantially perpendicular to the S H and Hoshiri S L set at appropriate intervals, of Hokata S H and Hoshiri S L, both sides of the prediction target ground area G a As shown in FIG. 1,
[0013]
On the other hand, the possibility is no stable ground area G B slip destruction occurs, considering the wavelength of noise or the like to be removed, as a set different noise measuring line L 2 from each other in length, respectively a plurality of locations , set in different directions, the ground surface layer portion corresponding to both ends of each noise measuring line L 2 are embedded
[0014]
The ground strain signal measured in this way usually shows a gradual change in the order of several mV to several tens of mV, but the shear stress acting on the sliding surface LS inside the ground increases, and this slip When microfracture of the soil structure along the plane LS occurs, the amplitude of the ground strain signal changes on the order of several tens to several hundreds mV. The collapse of the prediction target ground area G A (surface layer slip destruction in sliding surface LS) are those that occur after such a large amplitude of ground distortion signal pattern (ground breaking aura signal) is measured continuously fixed time It is estimated to be.
[0015]
Therefore, before starting the cut slope S, a cylindrical core-shaped ground sample is collected in advance from the ground to be the ground area G A to be predicted by boring, and the moisture content is changed to this ground sample by laboratory tests. under the compression force conditions, giving strain by tensile or shearing force or the like, if grasp the correlation between the strain amount and the soil distortion signal in the prediction target ground area G a, the size and timing of destruction It is effective to estimate. Further, it large ground breaking omen signal amplitude, when only measured in part of the plurality of main measuring line L 1, the collapse is generated most easily in the main survey line prediction target ground area G A in the vicinity of It is estimated that
[0016]
Next, FIG. 3, the breakdown prediction method of the ground according to the present invention show a second embodiment applied to a prediction of tunnel Face destruction, reference symbol T denotes a tunnel, T A is支保the tunnel inner wall A tunnel lining body, T B, is an excavation surface (referred to as a face) at the tip of the tunnel, and this tunnel T is further excavated as shown by a one-dot chain line in the figure. In tunnel excavation T is the most unstable upper ground of Face T B and the vicinity thereof, yet in the process of excavating the underground portion of the surface becomes locally high as a hill GH, the working face T B increased soil pressure acting, the working face T B and the degree of instability of the upper ground in the vicinity thereof will increase.
[0017]
Accordingly, in this embodiment, the cutting face T B and the upper ground in the vicinity were approaching just below the hill G H a prediction target ground region G C, one or a plurality of main extending in the longitudinal direction of the prediction target ground region G C A survey line is set, and
[0018]
In the first and second embodiments described above, from the viewpoint of disaster prevention, an alarm device is provided that issues an alarm when the amplitude of the ground strain signal increases beyond a predetermined threshold and indicates a sign of ground failure. Is more preferable.
[0019]
Note that the ground failure prediction method of the present invention is not limited to the above-described slip slope failure of the cut slope and the face failure of the tunnel, but also as a failure prediction method of various artificially modified grounds such as the prediction of the breakage of the embankment due to embankment. Applicable.
[0020]
Also, in debris flow disaster risk areas and steep slope failure risk areas designated by the responsible government offices and municipalities, for example, noise measurement lines in multiple main survey lines and stable areas where electrodes are embedded on the low and high slopes, for example, By setting and measuring the ground strain signal due to the difference in geopotential in the same manner as described above, the location and time of occurrence of slope failure due to, for example, torrential rain caused by typhoons or relatively long-term terrestrial rain, etc. It becomes possible to specify. This also allows the municipal mayor to provide evacuation recommendations to residents and to provide data for designating evacuation areas.
[0021]
【The invention's effect】
According to the present invention, the following effects are realized.
(1) Since the ground potential difference caused by changes in the strain stress of the ground can be predicted by the ground potential difference measured between the electrodes in the ground, it can be implemented at low cost.
(2) Since it is easy to remove noise, it is possible to predict ground failure with a ground strain signal and to predict ground failure with high accuracy.
(3) By comparing the measurement data on multiple main survey lines, the place with the highest risk can be identified, and the time of occurrence of ground collapse can be predicted to some extent by the accumulation of data.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a first embodiment in which a ground failure prediction method according to the present invention is applied to prediction of slip failure on a cut slope.
FIG. 2 is an explanatory diagram showing a planar arrangement of survey lines in the first embodiment.
FIG. 3 is an explanatory view showing a second embodiment in which the ground destruction prediction method according to the present invention is applied to prediction of tunnel face breaking.
[Explanation of symbols]
1, 2, 5, 6 Electrode 4 Ammeter G A , G C Predicted ground area G B Stable ground area
Claims (1)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25140697A JP3803470B2 (en) | 1997-09-02 | 1997-09-02 | Ground fracture prediction method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25140697A JP3803470B2 (en) | 1997-09-02 | 1997-09-02 | Ground fracture prediction method |
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| Publication Number | Publication Date |
|---|---|
| JPH1183558A JPH1183558A (en) | 1999-03-26 |
| JP3803470B2 true JP3803470B2 (en) | 2006-08-02 |
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| JP25140697A Expired - Fee Related JP3803470B2 (en) | 1997-09-02 | 1997-09-02 | Ground fracture prediction method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP5198825B2 (en) * | 2007-10-12 | 2013-05-15 | 株式会社間組 | Disaster prevention monitoring system and disaster prevention monitoring method |
| JP5408908B2 (en) * | 2008-06-03 | 2014-02-05 | 東日本高速道路株式会社 | Landslide prediction system |
| JP4900615B2 (en) * | 2008-12-26 | 2012-03-21 | 独立行政法人土木研究所 | Ground failure / collapse prediction method |
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