すべり面粘土の物理的・力学的特性
スポンサーリンク
概要
- 論文の詳細を見る
Abstract Observation on sliding surfaces in situ in several landslide areas has led to the recognition that sliding surface consists of a zonal structure. The zonal structure is composed of a fine clay seam of 3-8 cm of thickness and a conglomerate clay zone from top to bottom. In the fine clay seam, a piling of thin clay slices of 1-5 mm of thickness and many micro-cracks due to displacement shears are observed. These displacement shears are more dominant in the fine clay seam than are in conglomerate clay zone, to be well attributed to the principal displacement shears as has been defined so by Skempton, A. W.<BR>Soil samples of fine clay seam and conglomerate clay zone were taken in collecter wells and put to soil tests. The characteristics thus found are summerized as follows:<BR>(1) Fine clay seams are 0.5-16% higher in water content and 5-15% higher in clay fraction (<5μ) as compared with conglomerate clay zones.<BR>(2) The sheared surface made with ring-shear-apparatus test had a zonal structure, the thickness being 0.5-1.5mm, and the water content being 0-20% higher than the upper and lower parts.<BR>(3) The shear strength of fine clay seam was 1-7 degree smaller in the angle of shearing resistance than that of conglomerate clay zone. To note here is that, though the displacement be greatest in the fine clay seam, the displacement reaches to a certain height above (or below) the principal displacement shears, and that the displacement relative to the principal shear gets smaller as the height increases.