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未固結堆積物を定方位で連続的に採取する方法として独自に考案・開発した地層抜き取り装置と, 建設現場ですでに確立している鋼矢板打ち込み工法を組み合わせた定方位連続地層採取方法を提唱する. 本方法の原理は, 2つに分割したサンプラーを2段階に分けて地層中に差し込んで地盤中で閉合した断面を完成させ, それを同時に地盤から引き抜くことにより, その間に挟まれた地層を定方位で採取する方法である.本方法は, 活断層調査の現状における様々な問題点を克服するために開発されたもので, 2つの事例 (糸魚川-静岡構造線活断層系・神城断層と東京都旧江戸川) を示す. 糸魚川-静岡構造線活断層系・神城断層では幅35cm, 厚さ12cm, 深さ約11mの連続する定方位地層断面を2本採取し, 急傾斜する地層を切る小断層がとらえられた. 東京都旧江戸川では水深5mの川底から深さ約9mにわたって完新世の軟弱な未固結堆積層を幅30cmの地層断面として採取し, 縦ずれ量約25cmの連続する正断層状の地割れを含む地層断面を採取した. これらの採取結果から本方法が, 軟弱な未固結堆積物の定方位連続地層採取方法として広範に有効であることが明らかとなった.

The enormous earthquake on 17th January caused the calamity mainly in Kobe district and northern part of Awajisima-Island. More than five thousand people was killed and many houses were destroyed. Big fault (Nojima-earthquake-fault) caused to this earthquake. This fault has 14 kilometers in length from Ezaki lighthouse to Ikunami on the island and has right-lateral horizontal displacement. The maximum horizontal and vertical displacement are 1.7 m and 1.2 m respectively at Nojima-Hirabayashi in Awajishima-Island. This is the first report on the distribution and movement of the fault and disasters of houses, embankments and a transmission tower based on the site investigation and aerophotograph interpretation.

Alteration, which weakens rock mass and reduces the dry density, is one of the essential subjects in the foundation engineering. Case study has been carried out in which the alteration zone was to be grasped by the estimation of the density with the mean of geostatistics. The distribution of the dry density in whole mass was estimated from measured data of limited numbers of cores bored vertically and compared with the data measured horizontally. The result shows that the shape of histogram of estimated density was very similar to the measured one, while the density itself was not estimated precisely. Therefore, the geostatistics is able to be applyed to estimate many properties of rock mass other than alteration.