| 講演要旨(和文) | | 近年,地球温暖化などの影響により,ゲリラ豪雨と呼ばれる予測困難な集中豪雨が多発して,日本各地で土石流・地すべり・崖崩れなどの土砂災害が多く発生している.このような自然災害は,道路や鉄道などの交通機関だけではなく,家屋および人命にも被害を及ぼしているのが現状である.斜面崩壊との因果関係のある岩盤の不連続面の形状や水理特性などを精度よく評価できる手法の確立が望まれている. 本研究では,対象となる斜面にある水位観測孔へ注水し,注水の前後で比抵抗3次元探査を実施し,変化率を算出した.変化率から亀裂が卓越している脆弱部の検出,および脆弱部の走向傾斜の推定を行った.また,比抵抗の変化率にArchieの式を適用させることで,ボーリング孔への注水前の飽和度の分布状況の推定を試みた.さらに,比抵抗とRQDの相関関係から,比抵抗3次元探査で得られた比抵抗分布からRQDへの変換を試みた. |
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| | 講演要旨(英文) | | Recently, a lot of difficult localized torrential rains to forecast of calling a guerrilla downpour has been generated by the influence of global warming. Sediment disasters such as the mud flow, landslides have been generated by the guerrilla downpour in various places of Japan. In these natural damages, they are not only the transportation such as roads and railways but also it is current states to have done the house and the life damage. The establishment of the technique that can do the accuracy evaluation of shape and hydraulic characteristics of the discontinuity in the bedrock with the causal relation with the slope failure is hoped for. In this report, 3-D electric survey was executed before and after pouring water in the water level observation hole in the slope. The change rate of the resistivity was calculated by repeated survey. Position and strike and dip of weak parts were presumed from the change rate. Next, the saturation was presumed by applying the expression of Archie to the change rate of the electric resistivity. In addition, conversion from the electric resistivity that had been obtained because of 3-D electric survey to RQD was tried from the correlation of the resistivity and RQD. For the reasons stated above, 3-D electric survey is very useful for detail investigation for a slope. |
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